Synonymies are limited to key citations and illustrations. All illustrated specimens are shown at the same scale. Many species descriptions are based on the P1 element only. All figured specimens are located and stored in the Paleontological Institute and Museum of the University of Zurich (PIMUZ), Karl-Schmid-Strasse 4, 8006 Zürich, Switzerland. Suprageneric classification is following mostly Donoghue et al. (2008) and Orchard (2005). The terminology for the orientation of the element is the traditional one based on the orientation and curvature of the cusp. It only refers to the element itself and not its natural orientation within the animal (Purnell et al., 2000). ‘Lower’ refers to the side of the element from which the basal cavity opens. ‘Upper’ refers to the opposite side. The term ‘cusp’ refers only to the cusp sensu stricto (Klapper & Philip, 1972). For the figures, the orientation is standardized with the anterior side to the top, and the denticles tips to the left in ‘lateral’ views. For each element, the order of views from left to right is ‘lateral’, ‘oral’ and ‘aboral’ views, unless otherwise specified.
Class CONODONTA Eichenberg, 1930
Division PRIONIODONTIDA Dzik, 1976
Order OZARKODINIDA Dzik, 1976
Superfamily GONDOLELLOIDAE (Lindström, 1970)
Family GONDOLELLIDEA Lindström, 1970
Subfamily GLADIGONDOLELLINAE Hirsch, 1994
Genus GLADIGONDOLELLA Müller, 1962
1968 Dichodella Mosher, p. 923
Type species. Polygnathus tethydis Huckriede, 1958, p. 157–158, pl. 2, fig. 38a–b.
Type stratum and locality. Trachyceras austriacum bed (Julian), Feuerkogel near Röthelstein, Austria.
Remarks. This genus was first introduced by Müller (1962) for a Middle Triassic carminiplanate P1 element with a relatively short posterior process and corresponding keel posteriorly of the pit, a narrow platform and a low carina. As the type species may have been significantly different from some Spathian forms, the phylogenetic relationships of Gladigondolella are uncertain but the rootstock might lie within the evolution from Borinella (Orchard, 2007).
Gladigondolella laii Chen et al. morphotype A
Fig. 13B, C, G?
2013 Neogondolella sp.; Yan et al., fig. 6, nr. X.
2015 Neogondolella? n. sp. A; Chen et al., figs. 9.5–9.8.
2019 Neogondolella? n. sp. A; Chen et al., figs. 6.8, 6.9.
2021 Gladigondolella laii sp. nov.; Chen et al., figs. 4.20, 4.21 (only).
Material. ca. 15 specimens.
Diagnosis. Segminiplanate P1 element. Platform is arched, thickened and the platform margins are oriented orally. Denticles slightly fused at mid-length, larger and more discrete towards the anterior end.
Description. The element is arched in lateral view. In oral view, the margins of the thickened platform are subparallel at mid-length, and taper anteriorly. The platform is V-shaped, and the margin is directed orally. The cusp may be conspicuous in well preserved specimens. A posterior process may be present, which bears additional posterior denticles, otherwise the posterior margin is rounded. The carina denticles are partly fused at mid-length, taller and more discrete towards the anterior end.
Remarks. Gladigondolella laii differs from Borinella by having a more fused carina and an arched and thick platform whose margin are oriented orally. In comparison with the type species of Gladigondolella, a Middle Triassic species, the posterior process is much less developed and less arcuated in the carinal axis. Chen et al. (2015) rejected the assignment of their Ng. n. sp. A to Gladigondolella on the basis that posterior denticles are never present behind the cusp. In our material (e.g. Fig. 13C) small denticles are present occasionally. With the exception of these additional posterior denticles, our specimens resemble those of Chen et al. (2015) very closely, hence they are synonymized here. Implicitly we assume there is variation within the species, a small posterior process being present or not. This taxon is thought to be intermediary between Borinella and Gladigondolella, but through the shared derived characteristic of the posterior cusp we determine it as the former genus. Chen et al., (2019; figs. 6.8, 6.9) illustrated similar and coeval (associated with Ic. collinsoni) elements from Oman, which they assigned to Neogondolella n. sp. A. Their illustrated specimens more closely resemble Gladigondolella tethydis (Huckriede) and were later assigned to a new species of Gladigondolella: Gladigondolella laii (Chen et al., 2021). To date Gladigondolella is mostly known from the Middle Triassic (e.g. Goudemand et al., 2012a; Orchard et al., 2007a, 2007b). If, as it seems, the here illustrated specimens and/or those from Chen et al., (2019, 2021) do indeed belong to Gladigondolella, then they represent their oldest known representatives of this genus so far. A few unpublished specimens from middle Smithian rocks of Oman may also belong to this genus (Leu et al., submitted; L. Dudit, pers. comm.), which further question the origin and age of Gladigondolella. Its preference for deeper, colder habitats (Trotter et al., 2015) may then explain its spotty occurrences within the Early Triassic, preferably during relatively colder intervals and/or in deeper, colder refuge areas like Oman.
Occurrence. South China; Ic. collinsoni and Tr. homeri zone, Jiarong (Chen et al., 2015). Bed 54, Luolou formation, Ic. collinsoni and Tr. homeri zone, Bianyang section, Guizhou (Yan et al., 2013).
Gladigondolella laii Chen morphotype B
Fig. 13E, F, H, I
2015 Neogondolella? n. sp. B; Chen et al., figs. 9.9–9.10.
2019 Neogondolella? n. sp. A Chen; Liu et al., p. 14, pl. 4, fig. 19 (only).
2019 Neogondolella? n. sp. B Chen; Liu et al., p. 14, pl. 4, fig. 9.
2021 Gladigondolella laii sp. nov.; Chen et al., figs. 4.5, 4.22, 4.25, 4.26 (only).
Material. ca. 20 specimens.
Diagnosis. Segminiplanate P1 element, narrow platform tapers towards the anterior, denticles moderately discrete. Very large, distinct, terminal, strongly reclined cusp.
Description. The platform is narrow, subparallel, slightly upturned and tapers towards the anterior end. The posterior margin is rounded in a narrow platform brim around the large terminal cusp. The cusp is massive and inclined posteriorly. The carina is moderately high with pointed denticles which are almost uniform in height.
Remarks. The large terminal cusp differs from Borinella whose denticles are also higher and more discrete, but resembles that of Scythogondolella. Yet, Gl. laii morphotype B lacks a prominent rounded basal loop surrounding a small pit, a distinctive feature of Scythogondolella. Chen et al. (2015) suggests that their Ng. n. sp. B could be a juvenile stage of Ng. n. sp. A (reassigned here and in Chen et al. (2021) to Gladigondolella laii see above) based on size considerations and the fact that they are both found in the same interval. Yet, they were not found in the same samples and the small forms (Gl. laii morphotype B) lack a posterior process, although the juvenile forms of ‘true’ gladigondolellids usually bear a posterior process. Hence, we tentatively keep them as separate morphotypes. Nevertheless, in Chen et al. (2021), both forms are found in the same sample (e.g. figs. 4.23 and 4.24) and can therefore be considered as different growth stages.
Occurrence. Ic. collinsoni and Tr. homeri zone, Luolou formation, Jiarong, Guizhou, South China (Chen et al., 2015).
Subfamily NEOGONDOLELLINAE Hirsch, 1994
Genus BORINELLA Budurov & Sudar 1994
1988 Pseudogondolella Kozur, p. 244.
1993 Kozurella Budurov & Sudar, p. 24.
*1994 (June) Borinella Budurov & Sudar, p. 30.
1994 (September) Chengyuania Kozur, pp. 529–530.
Type species. Neogondolella buurensis Dagis, 1984.
Type stratum and locality. Buur River Basin, Northern middle Siberia, Early Triassic Hedenstroemia Zone, Russia.
Remarks. The multi-element apparatus of this genus appears to be essentially the same as that of Neogondolella (Orchard, 2008). The P1 elements of the species of this genus all have in common discrete blade-carinal denticles that lengthen towards the anterior.
Borinella buurensis (Dagis, 1984)
Fig. 13A
1978 Neogondolella jubata Sweet; Weitschat & Lehmann, p. 98, pl. 13, figs. 1–6.
*1984 Neogondolella buurensis n. sp.; Dagis, p. 12, pl. 2, figs. 6–15, pl. 3, fig. 1–2, pl. 11, figs. 1–4, pl. 12, figs. 1, 2, pl. 16, figs. 1–4.
1984 Neogondolella elongata Sweet; Hatleberg & Clark, Pl. 1, fig. 14 (only).
2005 Neogondolella aff. sweeti Kozur & Mostler; Zhao, p. 131, pl. 13, fig. 1.
2007 Borinella buurensis (Dagis); Orchard, p. 113, pl. 1, nr. 7, 15, 27.
2008 Borinella buurensis (Dagis); Nakrem et al., p. 528, fig. 4.19.
2008 Borinella aff. buurensis (Dagis); Nakrem et al., p. 528, fig. 4.17–4.18.
2008 Borinella buurensis (Dagis); Orchard, p. 400, figs. 5.9–5.13.
2012a Borinella aff. buurensis (Dagis); Goudemand & Orchard in Goudemand et al., p. 1032, figs. 2AA.
2015 Borinella aff. buurensis (Dagis); Chen et al., fig. 9.11.
2018 Borinella aff. buurensis (Dagis); Maekawa in Maekawa et al., p. 45, fig. 29.27.
2019 Neogondolella ex. gr. jakutensis Dagis; Chen et al., figs. 4.3, 4.5 (only).
2019 Borinella aff. buurensis (Dagis); Liu et al., p. 13, pl. 3, fig. 10 (only).
2021 Borinella aff. buurensis (Dagys); Chen et al., fig. 5.9 (only).
Number of specimens. 5
Description. Subsymmetrical segminiplanate P1 element whose platform extends as a brim around the posterior edge, but not to the anteriormost quarter of the unit. In the posterior half, the platform margins are subparallel in oral view. The cusp varies in height and may be conspicuous. A smaller posterior denticle may be present in some specimens, in which case, it tends to be offset from the main axis. As in any Borinella species, the denticles become gradually more discrete and taller towards the anterior end. As illustrated by the figured specimen, whose denticles at mid-length are almost as high as the anteriormost ones, this denticulation gradient may be variable.
Remarks. Orchard (2007) suggested that the cusp of the P1 of B. buurensis is typically weak, contrary to that of B. sweeti. Our collections suggest instead it is variable, as illustrated here. In our view it is difficult to differentiate B. sweeti and B. buurensis.
Occurrence. South China; Nv. pingdingshanensis Zone, Tsoteng section (Goudemand et al., 2012b), Jiarong section, Guizhou (Chen et al., 2015): Southwest Japan (Maekawa et al., 2018): Boreal region; Hedenstroemia zone, Siberia (Dagis, 1984), Tardus zone, Canadian Arctic (Orchard, 2008), Spitsbergen (Nakrem et al., 2008; Weitschat & Lehmann, 1978).
Genus NEOSPATHODUS Mosher, 1968
Type species and holotype. Spathognathodus cristagalli Huckriede, 1958, pp. 161–162, pl. 10, fig. 15.
Type stratum and locality. Lower Ceratite Limestone (LCL), Mittiwali near Chhidru, Salt Range, Pakistan.
Neospathodus dieneri Sweet, 1970
Fig. 14H
*1970 Neospathodus dieneri n. sp.; Sweet, pp. 249–251, pl. 1, figs. 1, 4.
1982 Neospathodus dieneri Sweet; Matsuda 1982, p. 90, pl. 2, figs. 1–11.
1982 Neospathodus dieneri Sweet; Koike, p. 37, pl. 6, figs. 15–21.
1984 Neospathodus dieneri Sweet; Dagis, p. 27, pl. 6, figs. 4–7.
1991 Neospathodus dieneri Sweet; Beyers & Orchard, pl. 5, fig. 4.
2007 Neospathodus dieneri Sweet; Orchard & Krystyn, p. 33, figs. 3, 6, 7.
2007 Neospathodus dieneri Sweet; Zhao & Orchard in Zhao et al., p. 35, pl. 1, figs. 9A–C, 12A–B.
2009 Neospathodus dieneri Sweet; Igo in Shigeta et al., p. 186, figs. 151.6–151.16, 152.8 (only).
2009 Neospathodus dieneri Sweet; Orchard & Zonneveld., pp. 782–784, fig. 14, parts 1–4.
2016 Neospathodus dieneri Sweet; Maekawa et al., p. 199, figs. 4.8–4.10.
2018 Neospathodus dieneri Sweet; Maekawa in Maekawa et al., pp. 25–28, figs. 15.8–15.9, 15.12–15.14, 15.18–15.19, 15.21–15.28 (only).
Material. ca. 40 specimens.
Diagnosis. See Sweet (1970), pp. 249–251. The basal cavity is symmetrically rounded with a circular outline. The posterior margin is upturned. The denticles are round (subcircular in cross-section) with a pointy end, discrete and slightly recurved posteriorly. Basal groove runs from the basal pit to the anterior end.
Remarks. Zhao et al. (2007) distinguished three morphotypes of Neospathodus dieneri on the basis of the length of the terminal cusp relative to the other denticles. Their illustrated morphotype 3 (Zhao et al., 2007, Fig. 11A–C) however does not, in our opinion, belongs to N. ex gr. dieneri but is more closely related to N. cristagalli on the basis of its laterally flattened denticles and S-shaped posterior margin. Maekawa and Igo (2014, in Shigeta et al., 2014) assigned specimens to N. dieneri which is laterally flattened, blade-shaped denticles look very different from the holotype. They may instead belong to another species or even to another genus (possibly to Discretella?).
Occurrence. This species has been reported worldwide from the Dienerian and early Smithian. This includes South China (Zhao et al., 2007 and this study), Malaysia (Koike, 1982), the Northern Indian margin (Matsuda, 1982; Sweet, 1970), South Primorye in Russia (Shigeta et al., 2009), Canada (Beyers & Orchard, 1991) and Japan (Maekawa et al., 2018).
Neospathodus ex gr. cristagalli Huckriede, 1958
Fig. 14E
1970 Neospathodus cristagalli Huckriede; Sweet, p. 346, pl. 1, figs. 14, 15.
1982 Neospathodus cristagalli Huckriede; Matsuda p. 92, pl. 3, figs. 1–12.
2005 Neospathodus cf. cristagalli Sweet; Orchard, p. 89, text-fig. 14.
2014 Neospathodus cristagalli Huckriede; Maekawa & Igo in Shigeta et al., p. 223, figs. 161.10–161.12.
2015 Neospathodus cristagalli Huckriede; Maekawa in Maekawa et al., p. 315, figs. 5.4–5.6.
Material. ca. 30 specimens.
Remarks. In comparison with the holotype of N. cristagalli (Huckriede, 1958, Pl. 10, fig. 15), this element is much shorter, the basal cavity is oval, posteriorly rounded and only partly inverted, and the posterior triangular cusp is not conspicuously separated from the other denticles. Sweet still included such forms within N. cristagalli, but excluded similar forms with a rounded basal cavity and rounded, pointy denticles and assigned them to the then new species N. dieneri. In our opinion, such short elements where the cusp is not separated from the other denticles would deserve to be differentiated as a new species.
Occurrence. N. cristagalli is known worldwide in the Dienerian and earliest Smithian. It is not clear yet whether the present form is younger than N. cristagalli sensu stricto and occurs only close to the Dienerian–Smithian (Induan–Olenekian) boundary: Toad Formation, British Columbia (Orchard, 2005). Salt Range, Pakistan (Sweet, 1970). Guryul Ravine, Kashmir (Matsuda, 1982). Nanpanjiang basin; north-eastern Vietnam Flemingites beds within the Novispathodus ex. gr. waageni Zone (Maekawa et al., 2015; Shigeta et al., 2014). Luolou Formation, Flemingites limestone (this study).
Neospathodus bevelledi n. sp.
Figs. 15A, D, 16P–R.
1990 Neospathodus pamirensis n. sp.; Dagis, p. 79–80, pl. 4, fig. 8, pl. 6, fig. 9 (only).
2007 Neospathodus n. sp. V Orchard; Orchard, p. 96, fig. 2.
2013 Neospathodus cristagalli Huckriede; Yan et al., p. 516, fig. 6, I–L.
2014 Neospathodus spitiensis Goel; Maekawa & Igo in Shigeta et al., p. 233–236, figs. 167.17–167.30, 168.7–168.9, 168.16–168.27, 168.34–168.36, 169.4–169.9, 169.21–169.32, 170.1–3.
2014 Neospathodus sp. indet A Maekawa & Igo; Shigeta et al., p. 179, fig. 170.10–170.33.
2014 Novispathodus ex gr. waageni Sweet; Maekawa & Igo in Shigeta et al., p. 244, figs. 179.4–179.6, 179.13–179.15.
2015 Neospathodus cristagalli Huckriede; Chen et al., p. 112, fig. 8.12–13, 8.15.
2016 Neospathodus sp. indet A; Maekawa et al. p. 200, figs. 5.2–5.7.
2018 Neospathodus cristagalli Huckriede; Maekawa in Maekawa et al., p.22, fig. 14.24 (only).
?2019a Novispathodus pingdingshanensis Zhao & Orchard; Wu et al. figs. 32–34.
2021 Novispathodus waageni (Sweet); Sun et al., fig. 5.22 (only).
Etymology: named after the Latin (and British English) word ‘bevelled’, which refers to the wedge-like cessation of the denticles of the P1 element.
Holotype: specimen illustrated in Fig. 15A
Paratype: specimen illustrated in Fig. 15D
Type locality: Shanggang road cut, Luolou formation, Guangxi Province, China.
Type level: Luolou Formation, within the early-to-middle Smithian limestones (Owenites beds), 2–3 m above Flemingites limestone.
Material. > 10 specimens.
Diagnosis. A species with a segminate-to-carminate P1 element with distinctively wedge-shaped, bevelled denticle tips. Cusp is either terminal or in front of one or two posterior denticles. The shallow basal cavity is posteriorly elongated and tapered. In lateral view the lower margin is straight or upturned anteriorly, conspicuously upturned at mid-length, in front of the cusp, and straight or upturned posteriorly. The denticle directly in front of the cusp and above the kick in the lower margin may get broader towards its wedge-shaped tip and is usually conspicuously broader than the other denticles.
Description. The P1 element is segminate to carminate (the posterior process bearing one or two denticles) and has a rigid cockscomb-like form. In lateral view, the lower margin is conspicuously bent or upturned at mid-length, the anterior and posterior parts of the lower margin making an angle of 15° to 40° and being often offset. The anterior lower margin is straight or slightly upturned, the posterior lower margin is usually more upturned. The upper margin is arcuate, with a peak in height slightly behind mid-length. The length-to-height ratio of the element is about 1–1.2:1. The moderately fused and laterally flattened denticles seem to radiate from a point that is located below the element, slightly anterior of the lower margin kick. The denticles are usually slightly recurved posteriorly. The cusp is located directly behind the lower margin kick and is as high as, or smaller than the up to 2 posterior denticles. The denticle directly in front of the cusp is usually conspicuously larger and broader than the other denticles. It may get broader towards its characteristically wedge-shaped tip. In lower/aboral view, the shallow basal cavity is subtriangular, being elongated and tapered posteriorly. The posterior end of the basal cavity can be either pointy or sub-rounded (as in the holotype). A groove runs from the basal cavity pit to the anterior end.
Remarks. Orchard (2007) was the first to differentiate such forms on the basis of their wedge-shaped denticle tips (his Neospathodus n. sp. V). The holotype of Neospathodus pamirensis Dagis (1990) appears to fall within the scope of Ns. bevelledi n. sp. but Dagis differentiated Ns. pamirensis on the basis of a “sharply angular lower margin” of the P1 element and “cut-off ends” of the denticles (our rough translation from Russian), which based on his illustrations seem to correspond to sharply broken denticles, not to the wedge-shaped natural end that we use as a diagnostic feature of Ns. bevelledi n. sp., a feature that cannot be observed in his holotype of Ns. pamirensis. Moreover, the “sharply angular lower margin” does not differentiate his elements from those of Ns. spitiensis. Ns. bevelledi n. sp. compares most to Ns. cristagalli and Ns. spitiensis but none of the latter display the mid-length located, broad, large and bevelled denticle that is characteristic of Ns. bevelledi n. sp. Furthermore, Ns. spitiensis, as defined and illustrated by Goel (1977) has a similarly extended basal cavity and hence a similar lower margin but a much larger length-to-height ratio of about 1.8:1, its denticles being essentially smaller and more reclined posteriorly than in Ns. bevelledi n. sp. Maekawa and Igo (in Shigeta et al., 2014) assigned similar elements from Vietnam either to Ns. spitiensis or to their ‘Ns. sp. indet. A’. They differentiated ‘Ns. sp. indet. A’ on the basis that the P1 elements are higher and display fewer denticles. In our view, most of the elements they assigned to Ns. spitiensis are already too high to belong to Ns. spitiensis and most of them display the characteristic bevelled denticles that none of the original Ns. spitiensis possessed. Hence, they probably belong to Ns. bevelledi n. sp. instead. Their material, however, shows a possible somewhat continuous transition between Ns. spitiensis Goel and Ns. bevelledi n. sp., suggesting a close relationship between both taxa. In comparison with Ns. cristagalli, the P1 elements of Ns. bevelledi n. sp. are shorter and higher and although some elements display a posteriormost denticle that is triangular, it is neither smaller nor separated from the other denticles as is characteristic of Ns. cristagalli.
Occurrence. China: Bianyang and Jiarong sections, Nanpanjiang basin, Guizhou province (Chen et al., 2015; Yan et al., 2013); Japan: Taho Formation (Maekawa et al., 2018); Vietnam: Bac Thuy Formation, Smithian Flemingites to Owenites beds (Shigeta et al., 2014); Oman: Smithian age (Orchard, 2007).
Subfamily NOVISPATHODINAE Orchard, 2005
Genus NOVISPATHODUS Orchard, 2005
Type species and holotype. Neospathodus abruptus Orchard, 1995, pp. 118–119, figs. 3.23–24.
Type stratum and locality. Jabral Safra, Oman.
Remarks. The genus Novispathodus was introduced as a new genus with a 15-element apparatus by Orchard (2005) and revised by Goudemand et al. (2012b) based on the swapping of the S1 and S2 positions. Additional to the type species (Nv. abruptus) and other species whose multi-element apparatus has been reconstructed (e.g. Nv. pingdingshanensis (Goudemand et al., 2012b), Nv. waageni (unpublished)), we tentatively assign also the following species to Novispathodus on the basis that they co-occur with S and M elements that are reminiscent of Novispathodus.
Novispathodus pingdingshanensis (Zhao & Orchard, 2007)
Fig. 17D–F; M–P, R, S, U, X, AA, AB, AD, AF
*2007 Neospathodus pingdingshanensis n. sp.; Zhao & Orchard, Zhao et al., p.36, pl. 1, fig. 4A–C.
2012a Novispathodus pingdingshanensis (Zhao & Orchard); Goudemand & Orchard in Goudemand et al., p. 1030–1031, figs. 2B, F, G, I–J, M, P, Q, AD, 3T-U, 6.
2013 Neospathodus pingdingshanensis Zhao & Orchard; Chen et al., p 825, fig. 3.10, 3.12.
2013 Neospathodus waageni subsp. nov. A; Metcalfe et al., p. 1144, figs. 9.1–9.5, 9.7, 9.8, 9.10.
2014 Novispathodus pingdingshanensis (Zhao & Orchard); Maekawa & Igo in Shigeta, p. 239–240, figs. 171.13–171.31.
2015 Novispathodus pingdingshanensis (Zhao & Orchard); Chen et al., p. 111, 112, figs. 7.1–7.4, 8.5, 8.6.
2016 Novispathodus ex. gr. pingdingshanensis (Zhao & Orchard); Komatsu et al., p. 69, figs. 5.4a–5.5c.
2016 Neospathodus robustus Koike; Chen & Kolar-Jurkovšek in Chen et al., p. 93, fig. 9.5 (only).
2018 Novispathodus pingdingshanensis (Zhao & Orchard); Maekawa in Maekawa et al., p. 36–37, figs. 20.2–20.18, 21.1–21.13.
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Chen et al., fig. 3, nr. 8.
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Liu et al., p. 13, pl. 3 fig. 5 (only).
Material. > 100 specimens.
Diagnosis (Zhao and Orchard, in Zhao et al., 2007; emended by Goudemand, in Goudemand et al., 2012b). Small segminate P1 elements characterized by a length/height ratio in the range of 1.32–2.34, and about 4–9 robust, wide, mostly fused, and distinctively posteriorly recurved denticles. In lateral view, the basal margin is usually straight. A large, broadly expanded oval to sub-rounded basal cavity is upturned on the inner margin and flat to downturned on the outer margin.
Remarks. Goudemand (in Goudemand et al., 2012b) revised the original diagnosis by noticing that the basal margin is not necessarily straight and therefore, the most strikingly difference to Nv. waageni is the denticulation: the denticles axes are distinctively recurved posteriorly whereas in Nv. waageni and Nv. abruptus, the denticles are straight, inclined or radiating. The two or three denticles anterior of the cusp are often clearly asymmetrical and the posterior edge of the element is much shorter than the anterior one. In most sections worldwide, Nv. pingdingshanensis first occurs within the positive δ13Ccarb excursion of the latest Smithian and may extend to the earliest Spathian (Goudemand et al., 2019; Leu et al., 2019; Zhang et al., 2019). Some elements within our rich material resemble Ns. Pingdingshanensis, but appear to have a relatively small basal cavity, more posteriorly recurved denticles or more numerous denticles that what was previously described for this species. These elements (Figs. 17C, J, K, T; 18E, I–K; 19O, Q; 20H, N–O, S; here assigned to N. ex gr. pingdingshanensis) may deserve differentiation in the future. Two elements illustrated by Metcalfe et al., (2013, figs. 9.6, 9.9, p. 1144) as ‘Neospathodus waageni subsp. nov. A’ display a higher anterior end and more recurved denticles than the other elements they included in ‘Neospathodus waageni subsp. nov. A’, which we synonymized with Ns. pingdingshanensis: elements like these two elements do not seem to fit in Ns. pingdingshanensis and may deserve assignment to a new species. Some further elements resembling Ns. pingdingshanensis but distinctively shorter than Ns. pingdingshanensis are herein assigned to a new species (Nv. gryphus n. sp. see below).
Occurrence. Worldwide occurrence. China: Jinya/Waili area, Guangxi (Goudemand et al., 2012b) Jiarong, southern Guizhou (Chen et al., 2013, 2015). Anshun Fm., Qingyan section, Guizhou (Ji et al., 2011). Chaohu (Zhao et al., 2007, 2008). Daxiakou, Hubei (Zhao et al., 2013). Vietnam: Bac Thuy Fm., Xenoceltites variocostatus and Tirolites beds, (Komatsu et al., 2016; Shigeta et al., 2014). Canada: Scythogondolella mosheri zone, Wapiti Lake (Orchard & Zonneveld, 2009). Australia: Hovea Member of Kockatea Shale, upper part of Neospathodus waageni Zone, Smithian substage (Metcalfe et al., 2013).
Novispathodus gryphus n. sp.
Fig. 17G–I, K?, L
Etymology: from the Greek root ‘gryph’ referring to the hooked shape of the P1 element.
Holotype: specimen illustrated in Fig. 17H.
Paratype: specimen illustrated in Fig. 17L.
Type locality: Qiakong, Luolou formation, Guizhou Province, China.
Type level: Luolou Formation, within latest Smithian black shales.
Number of specimens. ca. 10 specimens.
Diagnosis. A species with a short segminate-to-segminiscaphate P1 element with 3 to 5 highly recurved denticles and a relatively large, sub-rounded basal cavity.
Description. The P1 element is segminate to segminiscaphate, the sub-rounded basal cavity extending to most of the length of the element with a tapering at the anterior end. The denticles are mostly fused and highly recurved posteriorly: although the denticles get larger from the anterior to the posterior, except for the posteriormost one, the height of the carina looks sub-uniform because of the way the denticles are recurved. The length-to-height ratio is about 1:1.
Remarks. These elements resemble strongly the homologous ones of Nv. pingdingshanensis, except that they are much shorter and bear less denticles, which are usually more recurved. Still, some may be confused with broken elements of Nv. pingdingshanensis whose anteriormost end is missing (Fig. 17G). Hence the anterior end must be inspected for traces of breakage. Although the specimens we have seen do not show obvious, surfacial traces of breakage, it is not excluded that some of these elements were broken and were subsequently repaired, thus covering such traces at the surface of the crown. Goudemand and Orchard (in Goudemand et al., 2012b) differentiated similar but longer elements as Nv. aff. pingdingshanensis (Goudemand et al., 2012b, figs. 2K, 2L) because they are lower and their denticles more recurved than in elements of Nv. pingdingshanensis: their denticles are so recurved that their upper profile appears straight; as such they are reminiscent of the present species, with whom they may be closely related. In comparison with Nv. soleiformis (Zhao & Orchard, 2008) Nv. gryphus n. sp. has a higher carina with less numerous but more posteriorly recurved denticles. Furthermore, the basal cavity of Nv. gryphus n. sp. does not extend as a wide deep groove anteriorly like in Nv. soleiformis.
Occurrence. Luolou Formation, within the latest Smithian black shales, Guangxi and Guizhou, South China (this study).
Novispathodus ex gr. abruptus (Orchard, 1995)
Figs. 16E; 17W, Y, Z, AE; 18H; 20A–G, K, L, M, Q, X
1981 Neospathodus homeri Bender; Koike, pl. 1, fig. 5.
1984 Neospathodus sp. A; Hatleberg & Clark, pl. 3, fig. 8, 21.
*1995 Neospathodus abruptus n. sp.; Orchard, p. 118, 119, figs. 3.16–3.19, 3.23–3.26.
2005 Novispathodus abruptus (Orchard); Orchard, p. 90, text-fig. 16.
2009 Novispathodus abruptus (Orchard); Orchard & Zonneveld, p. 784, fig. 15 parts 34–37.
2012a Novispathodus sp. nov. A; Goudemand & Orchard in Goudemand et al., p. 1031, figs. 2A, R?, Z?.
2012a Novispathodus sp. nov. B; Goudemand & Orchard in Goudemand et al., p. 1031, fig. 3V.
2018 Novispathodus abruptus (Orchard); Maekawa in Maekawa et al., p. 33, figs., 18.1–18.3, 18.20, 18.23, 18.24, 18.26, 18.27 (only).
Material. > 50 specimens.
Diagnosis. As in Orchard, 1995.
Remarks. Here we consider Nv. abruptus in a broad sense, including elements that correspond to Nv. abruptus sensu stricto together with forms that have been suggested to deserve assignment to separate species, such as Nv. sp. nov. A and Nv. sp. nov. B Goudemand and Orchard (in Goudemand et al., 2012b). We consider the most diagnostic feature of Nv. ex gr. abruptus is the terminal 1–3 progressively smaller denticles at the posterior end.
The P1 element of this species is less robust, more rectangular with more fused denticles than that of Ic. crassatus. Its morphology also recalls that of the homologous element in Nv. pingdingshanensis, but its basal cavity is relatively smaller and its denticles are not as posteriorly recurved nor usually as broad as in the latter. The P1 element of Tr. symmetricus has more posteriorly reclined denticles, it may have a small terminal denticle but not several of increasingly smaller size. Yet, the distinction between Tr. symmetricus and Nv. abruptus may be confusing. The P1 element of Tr. homeri has a more elongated basal cavity and a more developed, posteriorly reclined and laterally deflected process than in both Tr. symmetricus and Nv. abruptus. Goudemand and Orchard (in Goudemand et al., 2012b) implicitly suggested that elements like those of their Nv. sp. nov. B, where the small terminal denticles are not increasingly smaller but of equal (small) height instead, may be transitional between Nv. abruptus and Tr. homeri (compare the elements illustrated in figs. 2.9 and 3.17 of Orchard 1995, assigned to Tr. homeri and Nv. Abruptus, respectively). Note further that, based on the material from Tsoteng, it is likely that such P1 elements were still associated with a Novispathodus apparatus. This suggests that P1 elements like that of Tr. homeri may have evolved before the more substantial modifications of the rest of the apparatus implied by the difference between Novispathodus and Triassospathodus.
Occurrence. Worldwide occurrence in latest Smithian and early Spathian rocks. Xenoceltites and Tirolites beds within Nv. pingdingshanensis and Nv. brevissimus zones, Japan (Koike, 1981; Maekawa et al., 2018). Oman (Orchard, 1995). British Columbia (Orchard & Zonneveld, 2009), South China; Goudemand et al., 2012b; this study).
Novispathodus n. sp. Z Orchard, 2007
Fig. 20, I, J, P, AA
*2007 Ns. n. sp. Z; Orchard, p. 96, fig. 2.
2016 Novispathodus ex gr. abruptus (Orchard); Komatsu et al., p. 77, figs. 5.6a–c.
2018 Novispathodus abruptus (Orchard); Maekawa et al., p. 33, fig. 18.8.
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Liu et al., p. 13, pl. 3, figs. 3, 6 (only).
2019 Triassospathodus symmetricus? (Orchard); Chen et al., fig. 4.15.
Material. ca. 15 specimens.
Remarks. One small terminal denticle behind the cusp is present. The denticles are mostly fused, with subtriangular tips and increasingly reclined towards the posterior end. A moderately deep, conical, subcircular shaped basal cavity is present. The overall shape of the segminate P1 element is reminiscent of that of the sub-coeval Nv. pingdingshanensis or Nv. abruptus except that, contrary to Nv. pingdingshanensis, the denticles are reclined not recurved, and contrary to Nv. abruptus, there is only one small denticle behind the cusp, the latter being also conspicuously broader than adjacent denticles. Our specimens from China resemble the specimens from Panthalassa California (Darwin material), suggesting that this species may be important for worldwide correlations. Orchard (2007) mentioned, that Neospathodus kedahensis (Koike 1973) might be an available name for his Ns. n. sp. Z (Orchard 2007). However, Neospathodus kedahensis (Koike 1973) a Middle-to-Late Triassic species, lacks a conspicuous cusp and its posterior part is composed of slightly inclined and subequal denticles.
Occurrence. Taho Formation, Japan (Maekawa et al., 2018). North America (Orchard 2007, Goudemand et al., in prep.). Oman: Radio Tower section, UAZ5 (Chen et al., 2019), South China; Nanpanjiang basin: Bac Thuy Formation, Nv. pingdingshanensis zone (Komatsu et al., 2016); Qinglong Formation, Nv. pingdingshanensis Zone, Jiangsu Province (Liu et al., 2019) Luolou Formation, Qiakong section, Southern Gouizhou, China (this study).
Novispathodus brevissimus (Orchard, 1995)
Figs. 19A, B, D, F; 21A–J, L, M; 22B, C, E, F?
1981 Neospathodus triangularis Bender; Koike, pl. 1, fig. 6.
*1995 Neospathodus brevissimus n. sp., Orchard, pp. 117, pl. 3, figs. 14–15, 20–22.
2011 Neospathodus brevissimus Orchard; Ji et al., p. 219, fig. 3, nr. 7.
2014 Novispathodus triangularis (Bender); Maekawa and Igo in Shigeta et al., p. 241–243, figs. 172.1–9, 172.13–27, 173.1–3, 173.6–12, 173.16–21, 173.28–44, 174.1–174.24.
2015 Triassospathodus brevissimus (Orchard); Yan et al., p. 240, fig. 3.4.
2016 Novispathodus triangularis (Bender); Komatsu et al., p. 69, fig. 5.8.
2018 Novispathodus brevissimus (Orchard); Maekawa in Maekawa et al., p. 34, figs. 19.4, 19.5, 19.7.
2019 Neospathodus curtatus Orchard; Chen et al., fig. 6 nr. 13, 14.
2019 Neospathodus brevissimus Orchard; Chen et al., fig. 6 nr. 15.
2019a Triassospathodus brevissimimus [sic.] (Orchard); Wu et al., fig. 4, nr. 36.
2019 Novispathodus brevissimus (Orchard); Liu et al., p. 14, pl. 4, figs. 15, 18
Number of specimens. > 50.
Original diagnosis. “Species characterized by small, short, and high segminate elements with a length:height ratio of 1:1, about 8–12 largely fused, generally upright denticles atop a deep blade, and a large basal cavity with a subcircular basal outline that occupies most of the lower side” (Orchard, 1995).
Remarks. Characteristic of this species is the posterior lateral margin which is slightly to strongly curved. Subcircular to subtriangular outline of the large basal cavity in the lower view. The denticles are fused and compressed with an erect to radial outline (bouquet-like). The carina is relatively high. In lateral view, the upper edge is usually straight to slightly arched. Cusp is usually undistinguishable from other denticles.
The here illustrated adult specimens are a bit larger with more denticles than the holotype (Orchard, 1995; pp. 117, Pl. 3, fig. 22), but the denticulation and the convex posterior edge of the process is very distinct in this species. Therefore, the holotype (Orchard 1995) might represent a younger, juvenile morphotype of this taxon. Novispathodus eotriangularis (Zhao & Orchard in Zhao et al., 2007) has a more triangle-shaped basal cavity and the anterior half of the carina is gradually declining in height, whereas Novispathodus brevissimus shows a more abrupt decline at the posterior end. Compared to Novispathodus clinatus (Orchard 1995), this species shows more numerous, short and upright denticles. Novispathodus brevissimus shares most similarities with Novispathodus curtatus (Orchard, 1995), but the latter has a relatively smaller basal cavity, is longer and bears larger and more reclined denticles. Some specimens (e.g. Fig. 19F) bear the postero-lateral pinching that is usually considered diagnostic of Nv. triangularis (Bender), as revised by Orchard (1995). Chen et al. (2015) illustrated very similar specimens from a higher horizon (their figs. 7.9, 7.10). Contrary to ‘true’ Nv. triangularis, our specimens have more rounded denticles tips and the pinching is less conspicuous, suggesting they can still be retained within Nv. brevissimus sensu lato.
Occurrence. Oman, Jabal Safra, lower Spathian (Orchard, 1995); Japan, Taho Limestone, occurs with Nv. pingdingshanensis, Tahogawa Member (Koike, 1981; Maekawa et al., 2018); Nanpanjiang basin, South China and North Vietnam, together with Tirolites sp. nov. and Icriospathodus collinsoni (Komatsu et al., 2016; Liu et al., 2019; Shigeta et al., 2014; Yan et al., 2015).
Novispathodus expansus (Zhao & Orchard 2008)
Fig. 20U
2008 *Neospathodus expansus n. sp.; Zhao & Orchard in Zhao et al., p. 211, pl. 1, figs, 2a, 2b, 2c.
Submitted Novispathodus expansus (Zhao & Orchard); Leu et al., fig. 12Q.
Number of specimens. 5.
Remarks. Short robust denticles, a large basal cavity and a midlateral thickening are diagnostic for Nv. expansus. Some specimens of Nv. praebrevissimus n. sp. (Fig. 18O, P, T) feature a lateral, knob-like bulging on the flanks of the basal pit, but not a flange-like thickening along the mid-part of the carina as in Nv. expansus. Furthermore, in the latter the carina is lower than in Nv. praebrevissimus n. sp.
Occurrence. Columbites–Tirolites Zone, Nanlinghu Formation, Lower Triassic, Chaohu, Anhui Province, China (Zhao et al., 2008) Luolou Fm. Qiakong (this study); sample, JA15C, Jebel Aweri, Batain, early Spathian age, Oman (Leu et al., submitted).
Novispathodus clinatus (Orchard 1995)
Fig. 21K
*1995 Neospathodus clinatus n. sp. Orchard & Sweet in Orchard, p. 119, figs. 3.5–3.7
Number of specimens. 8
Remarks. This segminate element is relatively short and small. The basal cavity is subtriangular in outline. The posterior and anterior margins are abrupt and show both a bowed outline. The seven denticles are uniformly reclined. Other specimens assigned to Novispathodus clinatus sensu lato (e.g. Nv. aff. clinatus in Chen et al., 2015, fig. 5 or Nv. aff. clinatus in Maekawa et al., 2018, figs. 19.9–19.13) usually show a more elliptical basal cavity and a blade with a higher length: height ratio with more gradually declining denticles in the anterior part. This species resembles Nv. brevissimus with a subtriangular shaped basal cavity but the denticles in the latter species are less uniformly reclined and more numerous.
Occurrence. Top of Narmia Member of the Mianwali Formation at Narmia Pakistan (Orchard 1995); Laren section, Luolou Fm., Spathian, Guangxi, South China (this study).
Novispathodus praebrevissimus n. sp.
Figs. 17V; 18A–D, F, J–N, O?, P?, Q, S, T; 19R
1984 Neospathodus sp. aff. triangularis Bender; Hatleberg & Clark, pl. 3, fig. 16
2014 Icriospathodus? zaksi (Buryi); Maekawa & Igo in Shigeta et al., fig. 192, nr. 10–13 (only).
2015 Novispathodus brevissimus (Orchard); Chen et al., p. 111, fig. 7.8.
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Chen et al., fig. 3 nr. 5, 9 (only) fig. 5, nr. 6 (only).
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Liu et al., p. 13, pl. 3, fig. 7 (only).
Etymology: According to its presumed relationship as a predecessor of Nv. brevissimus.
Holotype: specimen illustrated in fig. 24R
Paratype: specimen illustrated in fig. 24Q
Type locality: Lilong cliff, Luolou formation, Guangxi Province, China.
Type level: Luolou Formation, within latest Smithian black shales. Present in UAZ5 which corresponds to the peak of the positive δ13Ccarb excursion and the Xenoceltites/Glyptophiceras beds.
Number of specimens. > 40.
Diagnosis. Short robust segminate P1 element. Large rounded-to-sub-rounded basal cavity. Posterior margin often slightly concave. Small, largely fused denticles. Groove from basal pit to anterior end.
Description. The segminate P1 element shows a very large rounded to sub-rounded basal cavity in the posterior half of the element. A very deep basal groove is present from the basal pit to the anterior end of the lower margin. The carina is relatively high with numerous small, fused denticles. The cusp is undistinguishable. The posterior lateral margin (posteriormost edge between basal cavity and last denticle) is slightly to strongly curved. Sometimes, the height of the posteriormost denticles is gradually but rapidly decreasing. In lateral view, the denticles tend to be radiating or recurved.
Remarks. This species is thought to be intermediate between Nv. pingdingshanensis and Nv. brevissimus. The P1 element of this species is very similar to that of Nv. pingdingshanensis, but the basal cavity is much larger and rounded. In comparison to Nv. brevissimus, this species is usually smaller and has a relatively bigger and more rounded basal cavity. Furthermore, the carina is lower, with less numerous denticles. The new species is distinguished from the similar Novispathodus shirokawai (Maekawa et al., 2018) by reclined and less pointy denticles, a larger, rounded basal cavity and a less triangular shape in lateral view. Compared to Ic. zaksi, the P1 element of this species is less robust and has a relatively higher carina. Ns. expansus (Zhao & Orchard) has a very similar morphology to Nv. praebrevissimus n. sp., but it has a distinct conspicuous thickening in the middle part of its unit. Some specimens of Nv. praebrevissimus n. sp. (Fig. 18L, O and P) show a bulbous thickening in the posterior part of the carina but never as pronounced as in Ns. expansus.
Occurrence. Spitsbergen, Botneheia Formation (Hatleberg & Clark, 1984). South China, Nanpanjiang basin: Jiarong, southern Guizhou (Chen et al., 2015). Luolou Formation, within latest Smithian black shales. Present in UAZ5 which corresponds to the peak of the positive δ13Ccarb excursion and the Xenoceltites/Glyptophiceras beds, Guangxi, South China (this study). Oman (Leu et al., submitted).
Novispathodus ex gr. waageni (Sweet, 1970)
Fig. 14C, D, F, G
*1970 Neospathodus waageni n. sp.; Sweet, pp. 260–261, pl. 1, figs. 11, 12.
1977 Neospathodus waageni Sweet; Goel, p. 1094, pl. 2, figs. 1–4.
1978 Neospathodus waageni Sweet; Weitschat & Lehmann, pl. 14, figs. 11–12.
1979 Neospathodus waageni Sweet; Solien, p. 292, pl. 3, fig. 9.
1980 Neospathodus waageni Sweet; Chhabra & Sahni, pl. 1, figs. 9–10, 14?, 16, 20?.
1982 Neospathodus waageni Sweet; Koike, p. 39, pl. 6, figs. 24–27.
1983 Neospathodus waageni Sweet; Matsuda, p. 88–91, pl. 1, figs. 6–10.
1984 Neospathodus waageni Sweet; Berry et al., p. 133, pl. 1, figs. 1–4.
1984 Neospathodus waageni Sweet; Dagis, p. 24, pl. 7, figs. 2–5, 7–10, pl. 8. fig. 7 (only).
2004 Neospathodus waageni Sweet; Zhao et al., figs. 1, 3.
2007 Neospathodus waageni Sweet; Zhao & Orchard in Zhao et al., pp. 36–37, pl. 1, figs. 5A, B, 10A, B.
2007 Neospathodus ex gr. waageni Sweet; Orchard & Krystyn, plate, figs. 8–18.
2008 Neospathodus waageni Sweet; Nakrem et al., figs. 5.7, 5.8, 5.11, 5.14.
2008 Neospathodus waageni Sweet; Orchard, p. 406, pl. 8, figs. 8.1, 8.2, 8.8, 8.9.
2009 Novispathodus waageni (Sweet); Orchard & Zonneveld, p. 785, figs. 13.1–13.10, 14, 15.
2009 Neospathodus ex gr. waageni Sweet; Igo in Shigeta et al., p. 194, figs. 152.1, 152.3, 152.14–15?, 152.1618, 152.19?, 153.8–9, 156.9, 156.14–19.
2010 Novispathodus waageni (Sweet); Beranek et al., figs. 6.22–23.
2012a Novispathodus waageni (Sweet); Goudemand & Orchard in Goudemand et al., p. 1031, figs. 3C?, D, E, H, N, S.
2013 Novispathodus waageni (Sweet); Zhao et al., figs. 9CC, 10A-H, 11F?, 11P-R?.
2014 Novispathodus waageni n. subsp. A; Goudemand, figs. 1A–1D
2014 Novispathodus ex gr. waageni (Sweet); Maekawa & Igo in Shigeta et al., p. 244, figs. 174.31–174.57, 175–178, 179.1–179.3, 179.7–179.12, 179.16–179.30, 180, 181.1–181.27.
2015 Novispathodus waageni (Sweet); Chen et al., figs. 6.23, 7.11, 8.3, 8.8, 8.9, 8.11, 8.14.
2016 Novispathodus waageni (Sweet); Liang et al., fig. 4.8.
2018 Novispathodus ex gr. waageni (Sweet); Maekawa in Maekawa et al., figs. 22.3, 22.10–11, 22.13?, 23.14–15, 23.18?.
2018 Novispathodus waageni (Sweet); Lyu et al., figs. 5, 6.
2019 Novispathodus waageni (Sweet); Lyu et al., figs. 7.8–10.
2019 Novispathodus waageni (Sweet); Souquet & Goudemand, figs. 3, 4a, 4g-4t.
2019 Novispathodus aff. waageni (Sweet); Souquet & Goudemand, figs. 4b–4f.
Number of specimens. > 50.
Diagnosis. See Sweet (1970).
Remarks. Despite the exclusion of several former morphotypes which have been formally described as separate species, this common species still encompasses a lot of variation in the P1 element and may deserve further differentiation in the future. Up to six morphotypes have been recognized by distinct authors, e.g. Zhao et al. (2004) or Orchard and Krystyn (2007), and several others later by Goudemand (unpublished Ph.D. thesis, 2011). It is not yet clear whether these various morphotypes may be of any utility and hence whether some of those may deserve assignment to separate species (see for instance Lyu et al., 2018 for a discussion on the value of N. waageni eowaageni).
Occurrence. N. waageni is a very common species in Smithian rocks worldwide. Its FAD has been proposed as a proxy for defining the base of the Olenekian (see discussions in e.g. Goudemand 2014; Lyu et al., 2018; Orchard, 2007, 2010; Orchard & Krystyn, 2007; Zhao et al., 2007; Shigeta, 2009).
Novispathodus n. sp. A
Figs. 19G, K, O, P, Q; 20T, Y, Z
2015 Novispathodus aff. Clinatus Orchard & Sweet; Chen et al., p. 111, fig. 7, nr. 6 (only).
Number of specimens. > 10.
Description. Segminate P1 element. 6–10 denticles present. The cusp is terminal and distinctly conical and often more reclined than anterior denticles. Anteriorly, the denticles are almost as high as the cusp and decline gradually towards the anterior end. The denticles are mostly fused and the cusp is conical or sometimes swollen at mid-height. The lower margin is straight to slightly upturned in the posterior half. Basal cavity rounded at posterior margin and tapers towards the anterior end. Basal groove runs from the basal pit to the anterior end.
Remarks. Similar to Nv. ex gr. pingdingshanensis in size and in its overall morphological outline, but differs by having a conical and terminal cusp. The denticles are straight, upright to slightly reclined, not recurved as in Nv. pingdingshanensis. In Nv. abruptus, the posteriormost denticles show a gradual decline that is not observed here. One of the elements illustrated by Chen et al. (2015) as Nv. aff. clinatus seems to fall within the variation of this species although it has more inclined posterior denticles.
Occurrence. In the late Smithian UAZ7 in Qiakong, Lilong, Guangxi, South China (this study).
Genus TRIASSOSPATHODUS Kozur et al., 1998
Type species and holotype. Spathognathodus homeri Bender, 1970, pp. 528–529, pl. 5, fig. 16a–c.
Type stratum and locality. Marmarotrapeza Formation, Marathovuno, Chios, Greece.
F23;F24
Triassospathodus symmetricus (Orchard, 1995)
Figs. 19H, I–M; 23A, B, D, E, H, I; 24C, I–Q
1970 Neospathodus homeri Bender; p.245, pl. 1, figs. 2, 3, 9, 10.
1970 Neospathodus triangularis Bender; Sweet, pp. 253–254, pl. 1, figs. 7, 8.
1973 Neospathodus homeri Bender; Mosher, p. 171, pl. 20, fig. 14.
1977 Neospathodus homeri Bender; Goel, p. 1097, pl. 2, figs. 10, 11.
1986 Neospathodus homeri Bender; Durkoop et al., pl. 20, figs. 9–10.
*1995 Neospathodus symmetricus n. sp.; Orchard, p. 120, 121, figs. 2.6, 2.10–2.13, 2.18.
2004 Neospathodus symmetricus Orchard; Koike, p. 137, figs. 35–38.
2007b Triassospathodus ex. gr. homeri (Bender); Orchard et al., p. 345, fig. 5.5, 5.6.
2009 Triassospathodus ex. gr. homeri (Bender); Orchard & Zonneveld, p. 788, fig. 15, parts 38–40.
2011 Neospathodus symmetricus Orchard; Ji et al., p. 219, figs. 3.5a, b, c.
2014 Triassospathodus symmetricus (Orchard); Maekawa & Igo in Shigeta et al., p. 254, figs. 182–185, 186.1–186.3
2015 Triassospathodus symmetricus (Orchard); Chen et al., figs. 7.16–7.17, 8.19, 9.15.
2015 Novispathodus abruptus (Orchard); Chen et al., figs. 8.2, 9.13.
2018 Novispathodus abruptus (Orchard); Maekawa in Maekawa et al., p. 33, figs. 17.22, 17.24, 17.25, 18.4–18.12, 18.14–18.22, 18.25, 18.28 (only).
2019 Triassospathodus symmetricus (Orchard); Chen et al., fig. 4, nr. 8, 1–13, fig. 5, nr. 4 (only)
Number of specimens. >50
Description. Segminate P1 element with length/height ratio of 2.0–2.5:1 and usually 10–13 subequal, variably fused denticles that become increasingly reclined posteriorly. Straight or arcuate upper margin, subtriangular denticles edges. The cusp is indistinct, it has as high or slightly higher than the other denticles. The basal margin is straight anteriorly and may be downcurved posteriorly. The margin of variably shaped basal cavity is expanded laterally and downturned posteriorly. A basal groove extends from the basal pit to the anterior end. Some specimens develop a midlateral rib.
Remarks. The elements are similar to Tr. homeri but usually shorter and they lack a ‘true’ denticulate posterior process: in Tr. symmetricus, the basal cavity is more or less rounded posteriorly, whereas in Tr. homeri it tapers posteriorly below the inturned posterior edge of the carina (Orchard, 1995). Some elements (Fig. 23B, E, H) may deserve differentiation in the future as they bear strongly reclined and gradually smaller, posteriormost denticles, as opposed to typical elements of this species.
Occurrence. Almost worldwide distribution. Nanpanjiang basin: North-eastern Vietnam, Bac Thuy Formation, Tirolites cf. cassianus beds (Shigeta et al., 2014). South China, Luolou Formation (several sections in this paper), Qingyan section, (Neospathodus homeri Zone, Ji et al., 2011); Northern Indian margin: Salt Range, Pakistan (Zone 9, Sweet, 1970). Spiti India (Goel, 1977), Oman, Jabal Safra (Orchard, 1995). Japan: Taho limestone (Koike, 2004). British Columbia: Canada (Keyserlingites subrobustus Zone, Mosher, 1973).
Triassospathodus aff. symmetricus (Orchard, 1995)
Figs. 18G; 24B, E, F
2004 Neospathodus sp. aff. N. symmetricus Orchard; Koike, p. 133, figs. 2.4–2.5.
2015 Triassospathodus symmetricus (Orchard); Chen et al., fig. 8.1.
Number of specimens. > 20.
Remarks. The biostratigraphical range of these specimens is usually slightly older than that of Tr. symmetricus. The P1 element of Tr. aff. symmetricus resembles that of Tr. symmetricus, but is shorter with fewer denticles and a more circular and larger outline of the basal cavity. The denticles are less inclined posteriorly compared to Tr. symmetricus and often have one additional small posteriormost denticle. Its denticles are not posteriorly arched as in Nv. pingdingshanensis. It differs from the very similar Nv. abruptus by having a downturned posterior part and posteriorly reclined denticles. This species might represent a transitional form between Novispathodus abruptus and Triassospathodus symmetricus but a multi-element apparatus reconstruction is currently lacking.
Occurrence. Taho Formation, Southwest Japan, Spathian age (Koike, 2004); South China, Luolou Formation, at the top of the black shales and the base of the nodular limestone in the earliest Spathian (this study).
Triassospathodus homeri (Bender, 1970)
Figs. 19C; 23C, F, G; 24A, D, G, H
*1970 Spathognathodus homeri n. sp.; Bender, p. 528, pl. 5, figs. 16a–c.
1970 Neospathodus homeri (Bender); Sweet, p.245, pl. 1, figs. 2, 3, 9, 10.
1980 Neospathodus homeri (Bender); Chhabra & Sahni, pl. 1, figs. 28 (only).
1983 Neospathodus homeri (Bender); Matsuda, p. 94–95, pl. 4, figs. 3, 4, 5.
1986 Neospathodus homeri (Bender); Durkoop et al., pl. 20, figs. 8a–d.
1995 Neospathodus homeri (Bender); Orchard, p. 115, figs. 2.1–2.3, 2.7–2.9, 2.14–2.17, 2.20, 2.21.
2005 Triassospathodus homeri (Bender); Orchard, p. 93, figs. 19.
2007 Triassospathodus ex. gr. homeri (Bender); Lucas & Orchard, p. 123, figs. 7.8, 7.9.
2007b Triassospathodus ex. gr. homeri (Bender); Orchard et al., p. 353, figs. 6, nr. 10–12.
2011 Neospathodus homeri (Bender); Ji et al., p. 220, figs. 3.9a, b, c.
2014 Triassospathodus homeri (Bender); Maekawa & Igo in Shigeta et al., p. 253, figs. 181.43–181.48.
2015 Triassospathodus homeri (Bender); Chen et al., figs. 7.13, 8.18, 9.14, 9.19.
2015 Novispathodus abruptus (Orchard); Chen et al., figs. 7.16–7.17, 9.16.
2019 Triassospathodus homeri (Bender); Chen et al., fig. 7, nr. 1.
2019 Triassospathodus symmetrucis [sic.] (Orchard); Liu et al., p. 12, pl. 2, fig. 11.
2021 Novispathodus abruptus (Orchard); Chen et al., fig. 4.3.
2021 Triassospathodus homeri (Bender); Chen et al., fig. 4.15, 4.16 (only).
Number of specimens: >30
Diagnosis. “Species with segminate elements that have a length:height ratio of 2.5–3:1, and commonly 15–18 subequal, moderately fused denticles that are increasingly reclined toward the posterior end where 3–5 small, low denticles occur on a short, variably inturned process. The posterior edge of the blade is moderately reclined. In basal outline, the basal cavity is elliptical, tapers in both anterior and posterior directions, and is strongly asymmetrical in specimens with an inturned posterior process.” (Orchard, 1995).
Remarks. This species may be slightly younger than the closely related Tr. symmetricus.
Occurrence. Worldwide distribution. Nanpanjiang basin: North-eastern Vietnam, Bac Thuy Formation, Tirolites beds (Shigeta et al., 2014). South China, (Orchard et al., 2007b, this study). Northern Indian margin: Kashmir (Matsuda, 1983). Jabal Safra, Oman (Orchard, 1995). Salt Range, Pakistan (Sweet, 1970). Western USA: Lower Spathian interval of Thaynes Group (Tirolites beds, Lucas & Orchard, 2007).
Genus ICRIOSPATHODUS Krahl et al., 1983
Type species and holotype. Neospathodus collinsoni Solien, 1979.
Type stratum and locality. Unit D, Thaynes Formation, near Salt Lake City, Utah, USA.
Remarks. Originally, the basis for establishing this genus was the characteristic ridge-like denticulation of the P1 element of Ic. collinsoni. Orchard (2005) reconstructed the multi-element apparatus of Ic. collinsoni, showing a smaller degree of denticulation of the P2, M and S elements in comparison to Novispathodus. Because their S elements (especially the S1) are significantly different from those of the subfamily Novispathodinae, he regarded their subfamily assignment as uncertain. Pending future multi-element reconstructions of the herein included taxa, we tentatively retain Icriospathodus within the Novispathodinae. The affinity of Ic. collinsoni, Ic. crassatus and Ic. zaksi was recognized in several studies (Koike, 1992; Orchard, 2007; Maekawa & Igo in Shigeta et al., 2014; Maekawa in Maekawa et al., 2018), and we follow these authors.
Icriospathodus collinsoni (Solien, 1979)
Fig. 25M, O, P
1964 Icriodus; Clark et al., p. 376, pl. 60, fig. 1.
1970 Neospathodus n. sp. G; Haselmüller, p. 45–47, pl. 2, fig. 12a–b.
1971 Neospathodus n. sp. G; Sweet et al., p. 453, pl. 1, figs. 12, 13
*1979 Neospathodus collinsoni n. sp.; Solien, p.302, pl. 3, figs. 10, 12–20
1981 Neospathodus? collinsoni (Solien); Koike, pl. 1, figs. 42–44.
1987 Neospathodus collinsoni (Solien); Zakharov & Rybalka, p. 43–44, pl. 5, figs. 4, 5.
1990 Neospathodus collinsoni (Solien); Metcalfe, p. 136, pl. 1, figs. 6, 7, 17.
1992 Spathoicriodus collinsoni (Solien); Koike, p. 357–361, figs. 11, 12.13–12.42, 12.44, 12.47–12.50, 13.8–13.37.
1995 Icriospathodus collinsoni (Solien); Orchard, p. 113, fig. 2.22–2.24.
2005 Icriospathodus collinsoni (Solien); Orchard, p.96, fig. 22A
2007 Icriospathodus collinsoni (Solien); Orchard p.96, fig. 2
2007 Icriospathodus collinsoni (Solien); Lucas & Orchard, p. 123, figs. 7.4–7.7, 7.13–7.15.
2011 Icriospathodus collinsoni (Solien); Ji et al., p. 221, figs. 5a–5c.
2014 Icriospathodus collinsoni (Solien); Maekawa & Igo in Shigeta et al., p. 260, figs. 186.10–186.22, 187–191, 192.1–192.6.
2015 Icriospathodus collinsoni (Solien); Chen et al., p.113, figs. 9.1–9.4.
2015 Icriospathodus collinsoni (Solien); Yan et al., p. 240, figs. 3.5, 3.6.
2016 Icriospathodus collinsoni (Solien); Komatsu et al., p. 69, fig. 5.9.
2018 Icriospathodus collinsoni (Solien); Maekawa in Maekawa et al., p. 49–51, figs. 28.5–28.10, 29.1–29.7.
2019 Icriospathodus collinsoni (Solien); Chen et al., fig. 6, nr. 10–12.
2019 Icriospathodus collinsoni (Solien); Liu et al., p. 14, pl. 4, figs. 6–8.
2021 Icriospathodus collinsoni (Solien); Chen et al., figs. 4.9–11.
Number of specimens: >40
Description. A robust segminate P1 element. The upper edge bears biserial or/and ridge-like denticles. The width of the denticles is usually longest in the middle part to the posterior third. The basal cavity shows a lot of variation, but is mostly asymmetrical.
Remarks. Koike (1992) showed a wide range of intraspecific variation within this species (see below). The two rows of nodes on the upper margin and the pairs of nodes connected by a ridge are diagnostic features that are easy to determine and miss-identification of even broken elements is unlikely. P1 elements of Eurygnathodus are superficially similar but they are scaphate, not segminate.
Occurrence. I. collinsoni indicates the early Spathian worldwide and generally co-occurs with the Tirolites and Columbites beds. USA: Idaho, (Zone 11, Sweet et al., 1971), Utah (Thaynes formation, Solien, 1979), Nevada (Lucas & Orchard, 2007), South China (Chen et al., 2015; Ji et al., 2011), Vietnam (Bac Thuy formation, Komatsu et al., 2016; Shigeta et al., 2014), Oman (Orchard, 1995), Primorye (Zakharov & Rybalka, 1987), Japan (Maekawa et al., 2018), Malay Peninsula (Metcalfe, 1990).
Icriospathodus aff. crassatus (Orchard, 1995)
Figs. 22A?, D?; 25G–L, N
2019 Icriospathodus crassatus (Orchard); Liu et al., pl. 4, figs. 10, 14.
Number of specimens: >30
Diagnosis. In lateral view, the segminate P1 element is subrectangular. Moderately fused carina. Denticles increasingly lower at both anterior and posterior ends. Posteriormost denticles often bent inwards. Basal cavity generally symmetrical and subquadrate to subtriangular in shape. Lateral margins and basal cup often relatively thick and sometimes accessory nodes on the latter.
Description. In oral view, the rather symmetrical large basal cavity looks bulbous. Laterally, the thick node-like, irregular denticles are lower and more bent inwards towards the posterior end. The basal cavity is symmetrical. The subterminal cusp is situated near the posterior end, up to two more reclined denticles being sometimes present behind it. The lower margin is downturned posteriorly.
Remarks. Orchard (1995) created Ic. crassatus for Ic. collinsoni-like elements that lack the ridge-like or paired platform nodes. Our specimens share the attributes of Ic. crassatus but their basal cavities are subsymmetrical, which is uncommon for Ic. crassatus. The elements of N. symmetricus have a similar outline in lateral view but have relatively higher and more uniform denticles with a pointy tip, and a relatively larger basal cavity. In our material, Ic. zaksi and Ic. aff. crassatus are morphologically similar, but Ic. aff. crassatus is longer, bears more denticles, has a relatively smaller basal cavity and is usually found in younger strata. Ic. zaksi may be a forerunner of Ic. aff. crassatus. In the material studied from South China, no “true” Ic. crassatus was found. In addition, all illustrated specimens from South China determined as Ic. crassatus from the literature can neither be determined as Ic. crassatus sensu stricto in the authors view. The specimen illustrated in Lehrmann et al. (2015) (fig. 5.16, 5.17), resembles more Tr. homeri (see Additional files). The studies from West and North Pingdingshan do either not provide any illustrations (Liang et al., 2011; Zhao et al., 2007, 2008) or the specimens cannot be determined as Ic. crassatus with certitude because the specimens are broken and resembles more Ic. cf. zaksi (Pl. 6 fig. 2) or Ic. cf. aff. crassatus (Pl. 12 fig. 11) in Zhao (2005). In Ji et al. (2011) the illustrated specimen from Qingyan consists of a large subsymmetrical basal cavity and resembles more Ic. aff. crassatus. The specimen determined as Ic. crassatus in Liu et al. (2019) is in the synonymy list of Ic. aff. crassatus (see above). Furthermore, the specimen illustrated in Yan et al. (fig. 6GG, 2013) resembles more Tr. homeri with an inturned posterior end. Therefore, it has to questioned if Ic. aff. crassatus is provincialistic of South China and is worth of defining a new species formally in the future.
Occurrence. South China, Nanpanjiang basin, Luolou Fm., Laren, Lilong, Shanggang top of black shales to nodular limestone, SSB and early Spathian, (this study).
Icriospathodus zaksi (Buryi, 1979)
Fig. 25A–F
*1979 Neospathodus zaksi Buryi, p. 60 pl. 18 figs. 3a, b.
2007 Icriospathodus? zaksi (Buryi); Orchard, fig. 2.
2013 Neospathodus novaelhollandiae McTavish; Yan et al., p. 516, fig. 6BB–DD.
2014 Icriospathodus? zaksi (Buryi); Maekawa & Igo in Shigeta et al., fig. 192, nr. 14–29.
2015 Novispathodus pingdingshanensis (Zhao & Orchard); Chen et al., p.111, figs. 7.1–7.2.
2016 Neospathodus planus sp. nov. Chen & Kolar-Jurkovšek; Chen et al., p.92, fig. 7.9a–c, 8.10.
2016 Neospathodus robustus Koike; Chen & Kolar-Jurkovšek in Chen et al., p.92, figs. 8.7–8.9.
2016 Icriospathodus? zaksi (Buryi); Komatsu et al., p. 69, fig. 5, nr. 2–3.
2018 Icriospathodus zaksi (Buryi); Henderson et al., p.18 pl. 1, figs. 18–19.
2018 Icriospathodus zaksi (Buryi); Maekawa in Maekawa et al., p. 51, figs. 29.20–29.26.
2018 Icriospathodus? sp. 1; Maekawa in Maekawa et al., p. 54, figs. 30.1–30.2.
2019 Triassospathodus symmetricus (Orchard); Chen et al., fig. 5, nr. 8 (only).
2019 Neospathodus ex. gr. planus Chen & Kolar-Jurkovšek; Chen et al., fig. 6, nr. 2.
2019 Icriospathodus zaksi (Buryi); Chen et al., fig. 6, nr. 4, fig. 7, nr. 9, 10.
2019 Novispathodus pingdingshanensis (Zhao & Orchard); Liu et al., p. 13, pl. 3, fig. 4 (only).
Number of specimens: >30
Revised diagnosis. Low, robust segminate P1 elements usually with 8–9 wide denticles. 2–3 small denticles may be located behind the variably conspicuous cusp. Denticles are node-like in form. The lower margin is straight. Deep, wide basal cavity. One or two variably shaped, lateral processes are occasionally present.
Description. Robust segminate P1 element with 7–12 short, robust, erect to uniformly recurved, mostly fused, triangular-shaped denticles. Rectangular to subrectangular outline of the element. In most elements, the cusp is distinct. Unit lowest at the posteriormost end. Big sub-rounded, bulbous, slightly concave basal cavity. The basal cavity occupies the entire posterior half of the element. The posterior margin coincides with the edge of the cavity.
Remarks. The holotype (Buryi, 1979) has postero-lateral processes, which, in the original diagnosis were considered “complex in form” and characteristic of this species. Because the holotype is broken and the original diagnosis was based only on that specimen, we revise here the diagnosis on the basis of more than 30 specimens that show broader morphological variation in the platform: as illustrated by others (e.g. Chen et al., 2019), a lateral process may or may not be present. Koike (1992) reported a similar morphological variation within Ic. crassatus and Ic. collinsoni, suggesting it is a generic property of Icriospathodus. The P1 element of Ic. zaksi resembles that of Ic. crassatus but it is smaller, has a shorter carina and a much larger basal cavity relatively to its length.
Occurrence. Worldwide occurrence. India: Unit H3, Khunamuh formation, Guryul Ravine; North-eastern Vietnam: Novispathodus pingdingshanensis Zone, Xenoceltites variocostatus beds, Bac Thuy Formation (Maekawa & Igo in Shigeta et al., 2014); Russia: upper part of Anasibirites nevolini Zone to lower part of Tirolites cassianus Zone, South Primorye (Buryi, 1979); South China: Bed 51, Luolou Formation, Bianyang Section, Guizhou province (Yan et al., 2013); Canada: British Columbia, Montney Formation; late Smithian–early Spathian (Henderson et al., 2018). Oman; Wadi Bani Khalid section, UAZ4, Nv. pingdingshanensis range Zone (Chen et al., 2019); Japan: Taho Formation, Novispathodus brevissimus Zone (Maekawa et al., 2018).
Subfamily MULLERINAE Orchard 2005
Genus DISCRETELLA Orchard 2005.
Type species. Ctenognathodus discreta Müller 1956, p. 821–822, pl. 95, fig. 28.
Type stratum and locality. Smithian ammonoid bed, Crittenden Springs, Elko County, Nevada.
Discretella discreta (Müller, 1956)
Figs. 15C, G, L; 16D, S.
*1956 Ctenognathodus discreta n. sp.; Müller, pp. 821–822, pl. 95, fig. 28.
1989 Neospathodus discreta (Müller); Thang, p. 402, pl. 30, fig. 7.
2005 Discretella sp. A; Orchard, p. 83, fig. 8.
2008 Discretella discreta (Müller); Orchard 2008, p. 402, figs. 8.18, 8.19.
2010 Discretella discreta (Müller); Beranek et al., p. 65, figs. 6.18, 6.19.
2014 Discretella discreta (Müller); Maekawa & Igo in Shigeta et al., pp. 196–202, figs. 141.13–141.33, 142–145, 146.1–146.30.
2018 Discretella discreta (Müller); Maekawa in Maekawa et al., p. 23, fig. 14.4.
Number of specimens: >20
Diagnosis. See Müller, 1956.
Description. The carminate-to-segminate P1 element has an upturned and inverted basal margin in the posterior one-third to one-half of the element. The cusp is usually larger than the other discrete and upright denticles but not conspicuously.
Remarks. Maekawa & Igo (in Shigeta et al., 2014) described two different morphotypes, A and B, for Discretella discreta. Their morphotype A would correspond to the holotype (Müller, 1956) and their morphotype B has an upturned posterior margin and a relatively broader and triangular cusp. Although Maekawa & Igo (in Shigeta et al., 2014) have recently illustrated numerous specimens, the intraspecific variation of this species remains unclear due to its general scarcity. Based on their illustrations and unpublished material, there seems to be scope for further differentiation. Both morphotypes A and B have a posterior process and hence a tapered posterior margin of the basal cavity. However, some of our specimens do not develop a posterior process and have a rounded posterior margin at the basal cavity. Those are here assigned to a different species, which for now is kept in open nomenclature (Discretella aff. discreta).
Occurrence. Wide global occurrence in the Smithian. Meekoceras beds, Nevada (Müller, 1956). Euflemingites romunderi Zone, Canadian Arctic (Orchard, 2008). Jabal Safra, Oman (Orchard, 2005). North Vietnam (Thang, 1989). Nv. ex. gr. waageni Zone, Taho Formation, Japan (Maekawa et al., 2018).
Discretella aff. discreta (Müller, 1956)
Figs. 15B, J; 16C?.
1989 Neospathodus bransoni (Müller); Thang, p. 417, pl. 29, fig. 10.
2009 Guangxidella? sp. A; Orchard & Zonneveld, p. 780, fig. 14, parts 33, 34.
2013 Discretella discreta (Müller); Yan et al., p. 516, fig. 6W.
Number of specimens: >15
Diagnosis. Segminate P1 element with rounded, upturned basal cavity at the posteriormost part. Large conspicuous cusp above basal cavity. Discrete, smaller upright denticles in the anterior part.
Description. These P1 elements have markedly discrete denticles and a large cusp. The lower margin is straight in the anterior and upturned at the posterior part. The basal cavity is drop-shaped, being rounded at the posterior edge and tapered at the anterior end. The cusp is relatively large and reclined. A small, accessory, posterior denticle is occasionally present.
Remarks. In comparison to Discretella discreta, this species has a rounded posterior margin of the basal cavity, more discrete denticles and the cusp is relatively larger and often recurved. In lateral view, the lower margin is upturned as in morphotype B of Discretella discreta (Maekawa & Igo, in Shigeta et al., 2014).
Occurrence. Luolou formation, Owenites beds Smithian age, Shanggang road cut, Guangxi, South China.
Discretella pseudodieneri n. sp.
Figs. 15F, H, K, M, P; 16G–I, K, L, N, O
2013 Neospathodus dieneri Sweet; Yan et al., p. 516, fig. 6S (only).
2014 Neospathodus dieneri Sweet; Maekawa & Igo in Shigeta et al., p. 224, fig. 162, nr. 40–42, 46–54 (only).
2014 Discretella sp. indet. A; Maekawa & Igo in Shigeta et al., p. 202–207, fig. 151.13–151.15 (only).
2015 Discretella sp.; Chen et al., p. 112, fig. 8.12.
2018 Neospathodus dieneri Sweet; Maekawa in Maekawa et al., p. 26, fig. 15.32–15.34 (only).
2021 Neospathodus cf. dieneri discreta; Sun et al., fig. 5.10.
2021 Discretella sp. A; Sun et al., fig. 6.15.
Etymology: Named after its superficial resemblance to Ns. dieneri.
Holotype: specimen illustrated in Fig. 16O.
Paratype: specimen illustrated in Fig. 16H.
Type locality: Shanggang road cut, Luolou formation, Guangxi Province, China.
Type level: Luolou Formation, within the early-to-middle Smithian limestones (Owenites beds).
Number of specimens: >30
Diagnosis. Segminate P1 element, laterally flattened. Few, discrete, large denticles. Terminal cusp. Flat to slightly posteriorly upturned basal margin. Asymmetrical basal cavity.
Description. These P1 elements have markedly discrete denticles and a relatively large cusp, sometimes slightly larger than the other denticles that is situated terminally. In early ontogenetic stages (for adult forms, see Leu et al., submitted), the elements bear 3 erect to slightly and gradually reclined denticles. The basal margin is straight to slightly upturned posteriorly. In aboral view, the basal cavity is sub-rounded to lanceolate and asymmetrical.
Remarks. The P1 element of this species shows some superficial similarities with that of Neospathodus dieneri, but differs in being laterally flattened and having much less denticles (usually 3, vs. 5 to 10 in Ns. dieneri). Moreover, N. dieneri ranges up to the early Smithian only, whereas D. pseudodieneri occurs in the middle Smithian Owenites beds. Included here are also specimens where the cusp is less discrete, more robust and broader at the base (Figs. 15M, 16L).
Occurrence. Tahogawa Member, Olenekian Nv. ex gr. waageni Zone, Japan (Maekawa et al., 2018). Jiarong, Discretella discreta Zone, Smithian age Nanpanjiang basin, southern Guizhou, South China (Chen et al., 2015).
Discretella? n. sp. B
Figs. 15N; 16B
Number of specimens: >10
Diagnosis. Segminate P1 element with subsymmetrical, posteriorly rounded and anteriorly tapered basal cavity. Large terminal, subtriangular, recurved cusp. Anterior process bearing a few denticles only.
Description. The element shows a large cusp at the posterior end. In lateral view, the large, recurved, subtriangular cusp is about as high as the whole unit is long. An anterior process with two or three small upright to reclined denticles is present. The lower margin is straight to concave. In aboral view, the subsymmetrical basal cavity is sub-rounded at the posterior margin and tapers towards the anterior end.
Remarks. These P1 elements most closely resemble Discretella aff. discreta, but differ in having a much shorter anterior process and recurved denticles. They also bear some superficial resemblance with the P1 elements of the Spathian–Anisian genus Cornudina, but differ in their conformation of the basal cavity. Urdyella unicorna n. gen. n. sp. usually has a much thinner and larger, sickle-shaped cusp and a rounded basal cavity.
Because of the absence of a posterior process, some elements, especially arched ones, resemble homologous elements of Guangxidella and could possibly be assigned to that genus, but their basal cavity do not match those of Guangxidella and resemble instead that of Discretella aff. discreta, hence we tentatively retain them within Discretella.
Occurrence. South China: Luolou, Smithian age, Laren, Guangxi.
Discretella? n. sp. C
Figs. 15O; 16A, F, M.
1989 Cratognathodus sp. A; Thang, p. 405, pl. 32, fig. 8.
2013 Neospathodus? peculiaris Sweet; Yan et al., p. 516, fig. 6M.
2014 Discretella sp. indet. A; Maekawa & Igo in Shigeta et al., p. 202–207, fig. 151.1–151.12, 151.16–151.18 (only).
2014 Genus gen. indet. D; Maekawa & Igo in Shigeta et al., p. 269, figs. 193.10–193.12.
Number of specimens: >10
Diagnosis and description. Same as Discretella? n. sp. B except that a very small posterior process without denticle is always present and the laterally twisted basal cavity tapers at both ends. The anterior process may bear up to 5 denticles.
Remarks. The P1 elements of this species are very similar to those of the coeval Discretella? n. sp. B and both species may be conspecific although the presence of the incipient posterior process and the geometry of the basal cavity suggest they correspond at least to two different morphotypes, possibly due to sexual dimorphism. They also share strong similarities with the P1 of Discretella? n. sp. D, which may be a descendant of Discretella? n. sp. B via reduction/loss of the anterior process, forms like, Fig. 16M (and figs. 193.10–193.12 of Maekawa and Igo in Shigeta et al., 2014) that bear only one or two anterior denticles being intermediary. The relationship with Discretella sp. indet. A Maekawa & Igo is unclear but the P1 of the latter is almost identical, except that the incipient posterior process bears a small triangular denticle. Maekawa & Igo noted also that the anterior process of the P1 element of Discretella sp. indet. A (Maekawa & Igo) may also have been reduced over time. Conversely, Discretella robustus (Wang & Wang, 1976), which share a similar recurved cusp and a sigmoidal profile in lower view, has more developed anterior and posterior processes and may be their forerunner.
Occurrence. South China: Luolou, Smithian age, Laren, Guangxi.
Discretella? n. sp. D
Fig. 26AB, AC.
2014 Genus gen. indet. D; Maekawa & Igo in Shigeta et al., p. 269, figs. 193.8–9.
Holotype. Specimen illustrated in Fig. 26AB.
Number of specimens: >20
Diagnosis. Same P1 element as in Discretella? n. sp. C except it bears no anterior process.
Remarks. As for Discretella? n. sp. B and C (see above) the generic assignment of these forms is uncertain and may deserve a new genus name, especially given that the present taxa bear neither posterior nor anterior denticles.
Occurrence. Laren road cut, Luolou Formation, Smithian age, Nanpanjiang basin, South China (this paper); North-eastern Vietnam, Novispathodus ex gr. waageni Zone between Flemingites rursiradiatus beds and Urdyceras tulongensis beds and within the Owenites koeneni beds, Bac Thuy Formation (Shigeta et al., 2014).
Genus GUANGXIDELLA Zhang & Yang, 1991
Type species. Neoprioniodus bransoni Müller 1956, p. 829, pl. 95, figs. 19–21.
Type stratum and locality. Smithian ammonoid bed, Crittenden Springs, Elko County, Nevada.
Guangxidella bransoni (Müller, 1956)
Figs. 15E; 16E.
*1956 Neoprioniodus bransoni n. sp.; Müller, p. 829, pl. 95, figs. 19–21.
1956 Neoprioniodus bicuspidatus n. sp.; Müller, p. 828, pl. 95, figs. 16, 17.
1979 Neospathodus bicuspidatus (Müller); Solien, p. 302, pl. 3, figs. 2, 3.
1989 Ozarkodina gigantea n. sp.; Thang, p. 409, pl. 31, figs. 10, 14.
1991 Guangxidella typica n. sp.; Zhang & Yang, p. 33, pl. 1, figs. 1a, b, 2a, b.
2009 Guangxidella bransoni (Müller); Orchard & Zonneveld, p. 780, fig. 15, parts 26–28.
2014 Guangxidella bransoni (Müller); Maekawa & Igo in Shigeta et al., p. 211, figs. 152.16–152.18, 153–159, 160.1–160.4
2018 Guangxidella bransoni (Müller); Maekawa in Maekawa et al., p. 24, figs. 14.7–14.10.
Number of specimens: >30
Description. The segminate P1 element has variably discrete, laterally compressed denticles whose height decreases to the anterior and a very large, variably reclined, terminal cusp. The basal margin is up-arched and the basal cavity is flat, cordiform and asymmetrical.
Remarks. Gu. bicuspidatus was differentiated from Gu. bransoni on the basis of its closer spaced denticles, the one in front of the cusp being almost as high as the latter (Müller, 1956). Yet, given the broad range of intraspecific variation present in large collections such as those illustrated by Shigeta et al. (2014), it is in our opinion no longer tenable to keep both species separated. Although both taxa are defined in the same paper by Müller (1956) and the definition of Gu. bicuspidatus appears before that of Gu. bransoni, we have decided to name them bransoni because the etymology of bicuspidatus refers to a 2-cusp element, which is not typical of the revised species. Furthermore, Müller’s holotype of Gu. bicuspidatus is broken, whereas his holotype of Gu. bransoni is better preserved (not broken), better illustrated (also in aboral view) and corresponds better to the revised type.
Occurrence. USA: Dinner Springs Canyon, Lower Triassic Meekoceras beds, Crittenden Ranch, Elko County, Nevada (Müller, 1956); Thaynes Formation (Parachirognathus Zone, Utah, (Solien 1979). British Columbia, Canada (Orchard & Zonneveld, 2009). Taho Formation, Novispathodus ex. gr. waageni Zone) Southwest Japan (Maekawa et al., 2018). Nanpanjiang basin: Bac Thuy Formation, Owenites beds within the Novispathodus ex. gr. waageni Zone, North-eastern Vietnam (Shigeta et al., 2014). Luolou Formation, Neospathodus waageni Zone, Guangxi, China (Zhang & Yang, 1991).
Subfamily CORNUDININAE Orchard 2005
Genus SPATHICUSPUS Orchard 2005
Type species. Neospathodus spathi Sweet, 1970, pp. 257–258, pl. 1, fig. 5.
Type stratum and locality. Mittiwali Member, Mianwali Formation, Narmia, Pakistan.
Remarks. Based on his reconstruction of the multi-element apparatus of ‘Neospathodus’ spathi Orchard (2005) considered these taxa deserved assignment not only to a new genus, but also to a new subfamily.
Spathicuspus n. sp. A
Fig. 13M, P
2005 Neospathodus spathi Sweet; Gaetani et al., p. 288, pl. 1, fig. 2
2015 Spathicuspus spathi (Sweet); Chen et al., p. 112, fig. 8.16–8.17.
2015 Spathicuspus spathi (Sweet); Lehrmann et al., p. 123, fig. 5.28.
2016 Spathicuspus spathi (Sweet); Liang et al., p. 385, fig. 4.10.
Number of specimens: >10
Description. Short segminate P1 element with large, terminal, reclined or recurved cusp. Only two anterior denticles. Basal cavity is drop-shaped.
Remarks. Very similar to Spathicuspus? n. sp. B (see below), but much shorter and with a larger basal cavity. Similar elements have been illustrated from other Chinese sections by Chen et al. (2015) and Liang et al. (2016) and hence this species may be useful as an index fossil for intrabasinal correlations.
Occurrence. South China: Luolou Formation, Spathian, Nanpanjiang basin, Mingtang section, (Liang et al., 2016) Upper Guandao section, (Lehrmann et al., 2015), Triassospathodus homeri zone, Jiarong (Chen et al., 2015).
Spathicuspus? n. sp. B
Fig. 13J–L, O (N, R juvenile forms?)
2005 Spathicuspus sp. A; Orchard, p.77, fig. 2, Nr. A.
2016 Spathicuspus spathi (Sweet); Liang et al., p. 385, fig. 4.9.
2019 Spathicuspus spathi (Sweet); Chen et al., fig. 7, nr. 6–8.
2021 Spathicuspus spathi (Sweet); Chen et al., fig. 7.8 (only).
Number of specimens: >30
Description. Slender segminate P1 element with a terminal, reclined or recurved cusp that is usually broader than adjacent denticles, a shallow, posteriorly rounded basal cavity and three to seven anterior denticles.
Remarks. Despite their overall resemblance with Spathicuspus spathi these elements are either too long and bear too many denticles or their cusp is not broad and blunt enough to be assigned to that species. Some of them may not belong to Spathicuspus at all. Similar and apparently coeval elements were illustrated by Liang et al. (2016) and Chen et al. (2019) from other sections in China and Oman. The element illustrated by Orchard (2005) has similar aspect ratio and denticulation as for instance the specimen we illustrated in Fig. 13O, but it is also much younger and may be only superficially similar.
Occurrence. South China: Luolou Formation, Spathian, Mingtang section, Nanpanjiang basin (Liang et al., 2016), Upper Guandao section (Orchard, 2005). Oman: Wadi Bani Khalid section, Spathian UAZ7 (Chen et al., 2019).
F13
Spathicuspus? n. sp. C
Fig. 13Q
2016 Spathicuspus spathi (Sweet); Liang et al., p. 385, fig. 4.11.
2021 Spathicuspus spathi (Sweet); Chen et al., fig. 7.5 (only).
Number of specimens: >5
Description. Small P1 element with a rounded basal cavity, a large, reclined and broad cusp, a small posterior denticle and a couple of declining denticles to the anterior.
Remarks. Although the relationship of this species to Spathicuspus spathi and Spathicuspus n. sp. A is unclear, its shape is intermediate. It differs in the presence of a posterior denticle.
Occurrence. South China: Luolou Formation, Spathian, Mingtang section, Nanpanjiang basin (Liang et al., 2016).
Genus URDYELLA gen. nov.
Type species. Urdyella unicorna n. sp.
Type stratum and locality. Luolou Formation, Laren road cut, Guangxi Province, China.
Etymology: Named after Severine Urdy.
Diagnosis. Short coniform-to-segminiscaphate P1 element with a long cusp, usually at least twice the length of the adjacent denticle, a very short anterior process, and a broadly excavated basal cavity.
Remarks. The relationship of this genus to Cornudina is uncertain (Orchard, 2005, 2007). P1 elements similar to the P1 element of Urdyella n. gen. are often considered as belonging to Cornudina. Yet, as explained by Orchard (2005), the holotype of Cornudina (O. breviramulus) appears to be a P2 element. Both Kozur and Mostler (1971, p. 11) and Sweet (in Clark et al., 1981, p. W155) placed Cornudina with Chirodella as a multi-element Chirodella. The holotype of Chirodella (Metalonchodina triquetra) is an S2 element. The holotypes of both Cornudina and Chirodella are from Muschelkalk (Middle Triassic) collections made by Tatge (1956), who described no elements like those described by Orchard (2005) as P1. ‘Chirodella’ sensu formo does not occur in Orchard’s nor in Koike’s Spathian collections of Cornudina. For this reason, Koike (1996) and Orchard (2005) regarded the two genera as unrelated: Koike reconstructed Cornudina as an apparatus consisting of P1 and P2 elements only (Cornudina breviramulis) or of P1 elements only (Cornudina igoi), whereas Orchard reconstructed Cornudina? as having an octomembrate apparatus whose P2 element vaguely resembles the holotype of Cornudina, but he questioned the very validity of that name for Spathian forms that might be unrelated to the ‘true’ Middle Triassic Cornudina.
‘Chirodella’ sensu formo does not occur in our Smithian collections of Urdyella n. gen. and neither does ‘Cornudina’ sensu formo. Hence we suggest that Cornudina-like P1 elements found in the Smithian, and possibly those found in the Spathian, belong to Urdyella n. gen. not to Cornudina.
Based on multi-element considerations, Orchard grouped both ‘Cornudina’ and Spathicuspus within the same subfamily Cornudininae. Because Spathicuspus seemed to occur first, he hypothesized that ‘Cornudina’ evolved from Spathicuspus near the Lower/Middle Triassic boundary through overall shortening of the P1 element. Since Urdyella occurs already in the Smithian, we suggest that Spathicuspus may have evolved from Urdyella and the Spathian forms of ‘Cornudina’ either belong to Urdyella, derived directly from Urdyella, or as assumed by Orchard, evolved from Spathicuspus, although the latter hypothesis seems less likely. Urdyella itself may have evolved from Discretella via forms like Discretella? n. sp. B. Discretella has a much shorter cusp and a larger anterior process. Furthermore, the basal cavity in Urdyella is flatter and not as broadly excavated as in Cornudina.
Urdyella unicorna n. sp.
Fig. 26A–W, AE?
1970 Neospathodus peculiaris Sweet?; Hasenmüller, p. 62, pl. 2, fig. 10
2005 Aduncodina unicosta Ding; Zhao, pl. 6, nr. 9–10.
Etymology: Named after the unicorn, a mythical creature with a single horn on its forehead, for the huge cusp of the P1 element of this species.
Holotype: specimen illustrated in Fig. 26A.
Paratypes: specimens illustrated in Fig. 26K, Q, W.
Type locality: Laren road cut, Luolou formation, Guangxi Province, China.
Type level: Luolou Formation, upper Owenites to lower Anasibirites beds, middle Smithian to early late Smithian, Olenekian, Early Triassic.
Number of specimens. > 40.
Diagnosis. P1: Short coniform-to-segminiscaphate element with a very long, needle-like, recurved cusp, sometimes one (or two in large specimens) tiny, anterior denticle, and a broadly excavated basal cavity.
Description. P1: The cusp is about 3–4 times longer than the basal cavity is broad, is usually slightly recurved, sometimes only reclined, and it makes an angle of about 40°–60° with the baseline of the lower margin in lateral view. Many specimens are coniform and may bear a tiny anterior process, some (usually larger) specimens have a very short anterior process bearing up to two anterior denticles and may be better described as segminiscaphate. The deep basal cavity is oval to drop-shaped in aboral view. In lateral view, the base of the cusp occupies the anterior half of the basal cup.
Remarks. Specimens of this species were found by Zhao et al., (2007, without illustrations; but two specimens are illustrated in Zhao’s Ph.D thesis, 2005) in coeval strata of the Chaohu section, Anhui Province but reported as Aduncodina unicosta, a possibly related form that in all our collections from China is otherwise restricted strictly to the Spathian interval.
Occurrence. India: Mud, Mikin Formation, maximal horizon 1 (Goudemand, 2011); Western USA, Parachirognathus-Furnishius zone, Thaynes Formations, Utah (Hasenmüller, 1970). South China: Chaohu section, Anhui Province (Zhao, 2005; Zhao et al., 2007); Pingtang Syncline, uppermost Daye Formation and Luolou Formation, Smithian (this paper). Upper Smithian, Khunamuh Formation, Guryul Ravine, Northern Indian Margin (Leu et al. in prep.), Oman (Leu et al. submitted).
Urdyella tridenta n. sp.
Fig. 26X-AA
Etymology: The species is named after the trident, Poseidon’s weapon in the Greek mythology.
Holotype. Specimen illustrated in Fig. 26AA.
Paratype. Specimens illustrated in Fig. 26Z.
Number of specimens. 5
Diagnosis. Coniform P1 element with three subequally long and slightly recurved denticles all attached to the basal cup. Deep, teardrop shaped basal cavity. No clear anterior process.
Remarks. The P1 element of this species is very similar to the one of Urdyella unicorna n. sp. except for the lack of an anterior process and the fact that the single large cusp of Urdyella unicorna n. sp. is replaced by three subequally long denticles in Urdyella tridenta n. sp.
Occurrence. Laren road cut, Luolou Formation, Smithian age, Nanpanjiang basin, South China (this paper).
Urdyella n. sp. A
Fig. 26AE
Number of specimens. 1
Remarks. This one specimen does look like it may belong to Urdyella and it was found within the Smithian range of Urdyella, but it differs in its posterior configuration and in having a smaller cusp.
Occurrence. Laren road cut, Luolou Formation, Smithian age, Nanpanjiang basin, South China (this paper).
Genus NEOSTRACHANOGNATHUS Koike 1998
Type species. Neostrachanognathus tahoensis Koike 1998,
Type stratum and locality. The Taho Limestone, Ehime, Japan.
Neostrachanognathus n. sp. A
Fig. 26AD?
Number of specimens. 1
Remarks. That one specimen looks like it could be a P element of Neostrachanognathus as reconstructed by Agematsu et al. (2008). Since it possesses a posterior denticle, it does not belong to Neostrachanognathus tahoensis and may instead belong to Neostrachanognathus sp. A (Agematsu et al., 2008) or to a different species. This element was found in middle Smithian strata together with representatives of Urdyella spp. If it does indeed belong to Neostrachanognathus it is its oldest representative.
Occurrence. Laren road cut, Luolou Formation, Smithian age, Nanpanjiang basin, South China.
Genus ADUNCODINA Ding, 1983
Type species. Aduncodina unicosta Ding, 1983.
Type stratum and locality. Biandanshan formation, Mountain Majiashan of Chaoxian, Anhui province, China.
Aduncodina unicosta Ding, 1983
Fig. 24R–T
*1983 Aduncodina unicosta n. sp.; Ding, p.41, pl. 6, figs. 10–14, 20(?)-21.
1983 Cornudina cf. oezdemirae Gedik; Ding, p. 42, pl. 7, figs. 25–26
1998 Aduncodina unicosta Ding; Koike, p. 126, fig. 8.4–8.26.
2007 Aduncodina unicosta Ding; Orchard, p. 96, fig. 2
2019 Aduncodina unicosta Ding; Chen et al., figs. 5.7, 5.9, 6.6.
Number of specimens. > 30.
Description. Aduncodina unicosta has been reconstructed by Koike (1998) as a quadrimembrate skeletal apparatus encompassing only Sa–c (S1–3) and M nongeniculate coniform elements. The adenticulated, subsymmetrical element is regarded by Koike as the M element, whereas the denticulated elements are interpreted as pertaining to the S series, the subsymmetrical one that bears one denticle being the Sa (S0), the asymmetric one that bears up to three antero-lateral, hook-like denticles (in Zhao’s collections, those elements may bear up to five denticles, see his Ph.D thesis, 2005) and whose basal cavity is triangular in cross-section being the Sb (S1) and the asymmetric one with a lenticular basal cavity being the Sc (S2). All elements share common characteristics such as a thin wall, a relatively large and long and laterally flattened basal cavity. The slender cusp is suberect and subcircular in cross-section. Basal margin weakly to strongly convex anteriorly.
Remarks. We agree with Orchard (2007) that the reconstruction by Koike (1998) might be incomplete. Neostrachanognathus was also reconstructed by Koike (ibid) as including only coniform elements but later revised by Agematsu et al. (2008) with convincing evidence from natural assemblages as including also complex multidenticulate (bipennate) elements in the S positions. It is to be expected that Aduncodina too may possess complex multidenticulate elements in those positions. The morphology of the illustrated elements of Aduncodina unicosta resembles that of Ordovician forms such as Strachanognathus. In common with Neostrachanognathus, Aduncodina has a suite of denticulate elements, identified as Sb and Sc by Koike (1998), with an antero-lateral denticle or process that is directed posteriorward at its base, which is a feature of the Cornudininae (Orchard, 2007).
Occurrence. Japan: Taho Formation, co-occurrence with Ic. collinsoni in the Spathian substage (Koike, 1998); China: Biandanshan formation, co-occurrence with Ic. collinsoni and Tr. homeri, Mountain Majiashan of Chaoxian, Anhui province (Ding, 1983). Oman: Wadi Bani Khalid section, Spathian between UA10 and UA11 (Chen et al., 2019).
Subfamily UNCERTAIN
Genus EURYGNATHODUS Staesche 1964.
Type species. Eurygnathodus costatus Staesche, 1964
Type stratum and locality. Campiller member, Skyth, South Tirol, Italy.
Description. Scaphate P1 element bearing a variably broad, oval-shaped platform with or without transverse ribs. So far, the multi-element apparatus of Eurygnathodus is unknown.
Remarks. Recent discussions for the definition of the Global Stratotype Section and Point (GSSP) for the Induan–Olenekian Boundary (IOB) emphasize that this easily identifiable and cosmopolitan genus may be a useful index for the base of the Olenekian. Yet, its phylogenetic origin is still unclear, leaving opened the question of whether its seemingly sudden appearance in equatorial and tropical localities close to the IOB may reflect an ecological signal.
Eurygnathodus costatus Staesche, 1964
Fig. 14A
*1964 Eurygnathodus costatus n. sp.; Staesche, p. 269, pl. 28, figs. 1–6.
1977 Platyvillosus costatus (Staesche); Goel, p. 1098, pl. 2, figs. 15–21.
1981 Platyvillosus costatus (Staesche); Wang & Cao, p. 371, pl. 2, figs. 1–4, 28–30, 33.
1981 Platyvillosus paracostatus n. sp.; Wang & Cao, p. 371, pl. 2, figs. 9,10.
1984 Platyvillosus costatus (Staesche); Matsuda, p. 128, pl. 6, figs. 6–10.
1988 Platyvillosus costatus (Staesche); Koike, p. 65, pl. 1, figs. 1–57, pl. 2, figs. 1–37.
1991 Platyvillosus costatus (Staesche); Beyers & Orchard, pl. 5, fig. 10.
2009 Eurygnathodus costatus Staesche; Igo in Shigeta et al., p. 183, figs. 152.23–152.24.
2010 Eurygnathodus costatus Staesche; Orchard, p. 145, fig. 5.9–5.10.
2013 Platyvillosus hamadai Koike; Zhao et al., p.535, figs. 10K, L.
2013 Platyvillosus costatus (Staesche); Zhao et al., p.535, figs. 10M, 10N, 10O.
2014 Eurygnathodus costatus Staesche; Maekawa & Igo in Shigeta et al., p. 220, figs. 161.4–161.6
2015 Eurygnathodus hamadai Staesche; Maekawa in Maekawa et al., p. 316, fig. 5.1.
2016 Eurygnathodus costatus Staesche; Chen et al., fig. 11.3, 11.6–11.7.
2018 Eurygnathodus costatus Staesche; Maekawa in Maekawa et al., pp. 45–50, figs. 25–27.
2019 Eurygnathodus costatus Staesche; Li et al., p. 6, fig. 4.22–4.36.
2019 Eurygnathodus costatus Staesche; Lyu et al., fig. 7.12.
2019a Eurygnathodus costatus Staesche; Wu et al., fig. 4.20.
Material. > 30 specimens.
Remarks. Goel (1977), Matsuda (1984), Koike (1988) and Maekawa et al. (2018) documented a large intraspecific variation of the platform morphology and its oral ornamentation. It follows that Platyvillosus paracostatus Wang and Cao (1981) likely corresponds to a variant of Eu. costatus (Form A in Koike 1988). Maekawa et al., (2018, figs. 25.1d) documented also specimens covered with microgranules.
Occurrence. This species has been reported worldwide from the early Smithian Flemingites zone. Japan: Tahogawa member within the Novispathodus ex gr. waageni Zone (Koike, 1988; Maekawa et al., 2018), Europe: South Tyrol, Slovenia, Croatia and Bosnia and Herzegovina (Aljinović et al., 2006; Chen et al., 2016; Kolar-Jurkovšek et al., 2021; Staesche, 1964), India: Spiti and Kashmir (Goel, 1977; Matsuda, 1984; Orchard, 2010; Orchard & Krystyn, 2007), Russia; South Primorye (Shigeta, 2009), Canada: British Columbia (Beyer & Orchard, 1991), South China and North-eastern Vietnam (Chen et al., 2015; Shigeta et al., 2014).
Eurygnathodus hamadai (Koike, 1982)
Fig. 14B
1981 Platyvillosus costatus (Staesche); Wang and Cao, p. 371, pl. 2, figs. 31–32.
*1982 Platyvillosus hamadai n. sp.; Koike, p.45, pl. 5, figs. 10–36.
1988 Platyvillosus hamadai Koike; Koike, p. 71, pl. 2, figs. 38–45.
2010 Eurygnathodus hamadai (Koike); Orchard, p. 145, fig. 5.11.
2015 Eurygnathodus hamadai (Koike); Maekawa in Maekawa et al., p. 317, fig. 5.2.
2018 Eurygnathodus hamadai (Koike); Maekawa in Maekawa et al., p. 50, figs. 28.1–28.4.
2019 Eurygnathodus hamadai (Koike); Li et al., p. 6, figs. 4.37–4.45.
2019a Eurygnathodus hamadai (Koike); Wu et al., fig. 4.22.
Material. > 30 specimens.
Remarks. Eurygnathodus hamadai is easily distinguished from Eurygnathodus costatus by its smooth, flat upper surface lacking ornamentation. Koike (1988) reported transitional forms between E. costatus and E. hamadai (Morphotype δ), raising the question whether both forms may be conspecific, E. hamadai representing an extreme variant of E. costatus. In our material and in that of other authors, Eu. costatus and Eu hamadai co-occur in several samples. Their relative abundance, however, does change. Eu. costatus is more common in older strata, whereas Eu. hamadai is more abundant than Eu. costatus in younger strata. Although the FO of Eu. costatus appears to predate that of Eu. hamadai in several sections around the world, it is thus still unclear whether they share the same temporal range or not.
Occurrence. early Smithian in China (Wang & Cao, 1981, this study), Malaysia (Koike, 1982), Japan (Koike, 1988; Maekawa et al., 2018, and India, Spiti (Orchard, 2010).
Suborder PRIONIODININA Donoghue et al., 2008
Family ELLISONIDAE Clark, 1972
Subfamily HADRODONTINAE Koike, 2016
Genus HADRODONTINA Staesche, 1964
Type species. Hadrodontina anceps Staesche, 1964.
Type stratum and locality. Campiller member, Skyth, South Tirol, Italy.
Remarks. There is still an ongoing debate about the phylogenetic relationships of Pachycladina, Parapachycladina and Hadrodontina. Sweet (1988) in his prioniodinid phylogeny considered Pachycladina and Hadrodontina as sister taxa. Some species of Pachycladina were assigned to a new genus Parapachycladina by Shunxin et al. (1997), but this view is not widely accepted. Orchard (2007) observed that Hadrodontina anceps, Ellisonia aff. triassica and Pachycladina peculiaris appear to constitute a natural group, although they are currently assigned to different genera. Based on their cladistics analysis, Donoghue et al. (2008) concluded that Pachycladina is either a sister taxon to Ellisonia or stays unresolved in a polytomy with Ellisonia, Hadrodontina and Furnishius. Based on his multi-element apparatus reconstructions, Koike (2016) included Hadrodontina and Pachycladina within the subfamily Hadrodontinae (Koike, 2016), supporting the original view of Sweet (1988). We follow here this suprageneric classification and include Hadrodontina and Pachycladina within the subfamily Hadrodontinae. More recently, Sun et al. (2020) published 3 natural assemblages of Hadrodontina aequabilis and confirmed the suprageneric classification of Koike (2016).
In P1 elements, what most distinguishes Pachycladina from Hadrodontina is the basal configuration: the inverted basal ‘attachment’ surface of Pachycladina occupies the entire lower side plus one lateral side of the carina, whereas in Hadrodontina, a basal cavity with a deep basal groove is usually formed on the lower side and the attachment surface rarely extends over the mid-part of the keel, if at all. The denticles of Pachycladina are also less numerous but much larger in relative size than those of Hadrodontina. Based on multi-element reconstructions however, Koike (2016) showed that Pachycladina peculiaris, as well as Ellisonia aff. triassica (Koike et al., 2004), should be synonymized with Hadrodontina aequabilis.
Hadrodontina aequabilis Staesche, 1964
P1 elements: Figs. 27F–M; 28A, C, E
P2 elements: Figs. 27B–E; 28B, D
S2 elements: Fig. 27A
P1 element:
*1964 Hadrodontina aequabilis n. sp.; Staesche, p. 275, figs. 43, 44.
1984 Sweetocristatus unicus n. sp.; Dagis, pp. 37–38, pl. X, figs. 6–9.
1990 Pachycladina peculiaris n. sp.; Shunxin (Zhang), pl. 2, fig. 4
1991 Pachycladina peculiaris n. sp.; Zhang in Zhang & Yang, p. 40, pl. 3, figs. 1, 2.
1997 Parapachycladina peculiaris Zhang; Shunxin et al., pp. 65–69, pl. 1, figs. 1–2, pl. 2, figs. 1–2, pl. 3 figs. 1–2.
2004 Ellisonia sp. aff. E. triassica Müller, 1956; Koike et al., figs. 8.7, 8.8.
2009 Ellisonia? cf. peculiaris Sweet; Igo in Shigeta et al., p. 182, fig. 152.22.
2013 Parachirognathus geiseri Clark; Yan et al., p. 516, fig. 6 FF.
2015 Parachirognathus peculiaris Zhang & Guo; Chen et al., figs. 8.20–21, 24.
2015 Sweetocristatus unicus Dagis; Chen et al., fig. 8.23.
2016 Hadrodontina aequabilis Staesche; Koike, pp. 164–167, fig. 2, nr. 1–3.
2018 Hadrodontina aequabilis Staesche; Maekawa in Maekawa et al., p. 18, figs. 13.3?–13.4 (only).
2020 Hadrodontina aequabilis Staesche; Sun et al., figs. 1–7 (natural assemblage of the Hadrodontina apparatus).
P2 element:
*1964 Hadrodontina aequabilis n. sp.; Staesche, p. 275, fig. 44.
2004 Ellisonia sp. aff. E. triassica Müller; Koike et al., p. 247, fig. 8.6
2016 Hadrodontina aequabilis Staesche; Koike, p. 165, figs. 2.4 (P2 element).
2020 Hadrodontina aequabilis Staesche; Sun et al., figs. 1–7 (natural assemblage of the Hadrodontina apparatus).
S2 element.
2004 Ellisonia sp. aff. E. triassica Müller; Koike et al., p. 247, fig. 8.4
2016 Hadrodontina aequabilis Staesche; Koike, p. 165, figs. 2.9–11.
2020 Hadrodontina aequabilis Staesche; Sun et al., figs. 1–7 (natural assemblage of the Hadrodontina apparatus).
Material. P1, more than 40; P2, more than 40; S2 more than 10.
Revised diagnosis. Robust to slender angulate P1 element. The 6–8 (usually 7) denticles are rather short, radiating, conical, with subtriangular free ends and they are increasingly reclined towards the posterior. The concave lower side is occupied by a large and wide groove.
Remarks. The observed variation in the denticulation of the P1 and P2 elements suggests there may be scope for further specific differentiation: in some elements the height of the denticles changes smoothly along the unit (Fig. 28B), whereas in others the denticles are alternatively high and low (Fig. 28D). Dagis (1984) assigned some specimens (here considered as junior synonyms of Ha. aequabilis) to Sweetocristatus unicus. Yet, the genus Sweetocristatus Szaniawski (in Szaniawski & Malkowski, 1979) was established for Upper Artinskian to Lower Guadalupian (Permian) P1 elements that, although superficially similar to homologous elements of Hadrodontina and Pachycladina, bear a more developed, higher cusp, a higher carina and have a more elongated process. The cusp in Ellisonia P1 elements is more conspicuous than in those of Hadrodontina or Pachycladina. Chen et al. (2015) illustrated coeval specimens from Jiarong they assigned to either Sweetocristatus unicus or Parachirognathus peculiaris (see their figs. 8.20 and 8.23) but we fail to distinguish them from Hadrodontina aequabilis. With three natural assemblages of Hadrodontina aequabilis from the late Smithian Helongshan Formation, South China, Sun et al. (2020) observations fits with our findings; the angulate shape and no distinct cusp in the P1 element and the distally twisting shape of the P2 element.
Occurrence. Russia; Smithian Hedenstroemia and tardus zone, Siberia (Dagis 1984), Zhitkov Formation, Smithian age, Abrek Bay area, South Primorye (Shigeta, 2009). China; Beisi Formation, Taiping, Pingguo Western Guangxi Province (Shunxin et al., 1997), Luolou Formation, Smithian age, Jiarong and Bianyang, Nanpanjiang Basin, southern Guizhou Province (Chen et al., 2015; Yan et al., 2013), Late Smithian Helongshan Formation, Chaohu, Anhui Province (Sun et al., 2020). Japan: Taho Formation, Shirokawa-cho, Higashiuwa-gun, Ehime Prefecture (below Smithian–Spathian boundary) (Koike 2016; Koike et al., 2004). Europe: Campiller member, Werfen Formation, Skyth, South Tirol, Italy (Staesche, 1964), Slovenia (Kolar-Jurkovšek & Jurkovšek, 2019).