Order Cyrtocrinida Sieverts-Doreck 1952.
Suborder Holopodina Arendt 1974.
Family Cotyledermatidae Wright 1876.
Cotylederma Quenstedt 1852.
Cotylederma docens Deslongchamps in Deslongchamps and Deslongchamps 1858, Figs. 4, 5, 6, 7.
Material MHNLM 2015.1.39–2015.1.49 and 2015.1.51–2015.1.54. This species ranges from the upper Pliensbachian to upper Toarcian (Hess and Thuy 2016) and is represented by numerous disarticulated basal elements, radials, first and second primibrachials, and secundibrachials. Only in two specimens are radial circlets still attached to the basal element. Remains are especially common in the upper Pliensbachian (sample 355) and lower Toarcian (Tenuicostatum Chronozone, samples 267, 268, 354, 356–358, 425; and Serpentinum Chronozone, sample 350). Height of elements with similar diameter varies, and the largest basal elements reach a diameter of nearly 15 mm (samples 355–357). The species was thoroughly described by Loriol (1882) who noted the distinctive swollen first primibrachials. The present material includes primibrachials with peculiar concentric traces.
Diagnosis Aboral element thin-walled, hollow, of variable height and shape; upper margin with five weak depressions for radial circlet. Radial cavity wide and deep, extending into basal element. Radials symmetric, widening upward from narrow lower margin, joined by synostosis; articular facet with pair of small, deep, inward-sloping muscle fossae separated by a notch; ligament areas indistinct. First primibrachials trapezoidal in outline, often somewhat asymmetric; bulge on aboral side, leading to triangular profile in proximal or distal view; bulbous apex smooth and directed proximally; proximal and distal facets muscular, similar. Second primibrachials thick, trapezoidal. Secundibrachials thin, outline rectangular to skewed trapezoidal, food groove deep, articular facets muscular, no pinnule sockets.
Description The present material includes an aboral element with misformed cup of just one radial; the specimen’s first primibrachial (Fig. 6a) is in the body cavity, and on one side two budding extensions are visible that seem to be juvenile basal elements. Such elements were described by Rasmussen (1961, pl. 35, figs. 3, 4; as thecae) and Donovan and Jakobsen (2004, fig. 3a, c) from cups growing inside older cups of Cyathidium holopus from the Danian. Radials are narrow and vary in height (Fig. 5b, c, e); articular facets to first primibrachials have small aboral ligament fossae, flat interarticular ligament areas and small, circular and deep muscle fossae separated by a notch; and muscle fossae extend onto the adoral side and are rimmed. This morphology is mirrored in the proximal facet of the first primibrachials (Fig. 6d) that have muscular facets proximally and distally. First primibrachials are trapezoidal in outline, and food groove is narrow (Figs. 5c–e, 6d). A considerable number of first primibrachials have concentric furrows and folds around the bulge (Fig. 5c–e), and some have also scratch marks (Fig. 5d, e), see above. Second primibrachials are trapezoidal (Fig. 5b) to nearly triangular (Figs. 5a, 7a) and are slightly convex; some carry ichnological traces as discussed above. Second primibrachials are thin and rectangular (Fig. 7c) to skewed trapezoidal in outline (Fig. 7b, d, e) with muscular facets at both ends. The aboral surface is finely granular; an ossicle has distinct marginal crenulae (Fig. 7c).
Remarks The upper Pliensbachian C. inaequalis Hess (2006) differs from C. docens by having mostly asymmetric radials; primibrachials are highly variable in outline, and first primibrachials lack a bulge. Cotylederma ambiguum Manni and Nicosia (1990) from the lower Toarcian (Serpentinum Chronozone) of Italy seems to be conspecific with C. docens. C. docens is morphologically similar to upper Cretaceous to extant Cyathidium (see Heinzeller et al. 1996; Donovan and Jakobsen 2004; Hess in Hess and Messing 2011). In contrast to Cyathidium species, Cotylederma docens has unfused primibrachials, and the brachials lack cirri. Nevertheless, it appears to be a precursor to Cyathidium. Early growth stages of Cyathidium foresti have two primibrachials that fuse in later stages into a single element, and early stages lack pinnules that develop on first secundibrachials only in juveniles larger than 6 mm in diameter (Heinzeller et al. 1997). In the extant form, brachials close the gap left by the fused primibrachials and, thus, seal the body cavity (Heinzeller et al. 1997, fig. 2e); such sealing can be assumed for fossil Cotylederma. According to the diagnosis of Améziane et al. (1999), extant Holopodidae (including fossil Cyathidium) have a cup comprised of five fused radials attached directly to the substrate. In contrast, Cotylederma has a hollow, variable aboral element attached to the substrate; its narrow upper edge articulates to the radial circlet, forming a thin-walled bowl.
Cotederma miliaris Deslongchamps, 1858, Fig. 6f.
Material MHNLM 2015.1.50. One first primibrachial.
Description The ossicle is wide and narrow, and food groove is strongly displaced to one side making this part only half as wide as the other; the narrow part is raised distally at an angle of 10° and is indented at the outer margin, presumably for articulation with adjoining ossicle. Aboral surface is covered by coarse granules. Aboral ligament pit and axial canal are elliptical and separated by thin ridge. Muscle fossae are small and deep, and they are separated from the adoral notch by a small peak. Interarticular ligament areas are large and flat and on the proximal side are with scratch marks.
Remarks The ossicle differs from first primibrachials of C. docens in lacking an aboral bulge and in having a surface with coarse granules. Loriol (1882, pl. 19, fig. 18) described a similar ossicle from the site of May-sur-Orne and ascribed it to C. miliaris Deslongchamps. Loriol’s material included two such ossicles assumed to be first primibrachials; his material contained neither radials nor axillary second primibrachials. The present ossicle differs from the one described by Loriol by its asymmetric profile and wider food groove. It is possible that Loriol’s specimen represents a secundibrachial. Granular basal elements were also described by Loriol; they differ not only by their granulation but also by their vase-like profile from those of C. docens. In summary, ossicles of C. miliaris fall outside the range of C. docens, so that two species of the genus are represented at May-sur-Orne and Feuguerolles.
Family Eudesicrinidae Bather 1899.
Eudesicrinus Loriol, 1882 in Loriol 1882–1889.
Eudesicrinus mayalis Deslongchamps in Deslongchamps and Deslongchamps, 1858, Fig. 8.
Material MHNLM 2015.1.55–2015.1.60. Remains of this species include basal elements, mostly with attached radial circlet, cups (radial circlets), isolated radials, and secundibrachials. The best and most complete specimens are from the Tenuicostatum Chronozone (samples 357, 358, 425).
Description Our material of this well-known species is of interest, because it includes a juvenile cup less than 1 mm in diameter and height (Fig. 8a). In this specimen, radials are comparatively high and have identical size and facets; the basal element to which the radial circlet is fused is low. Cups with a diameter exceeding 1 mm have one radial enlarged (Fig. 8b, c), and such differentiation continues with growth to create the distinctive, inclined profile of the cup (Fig. 8d, e). The smallest specimen of the species from the Pliensbachian of Sulzkirchen (Jäger 1991, fig. 6) has a diameter of approximately 1 mm, with one radial enlarged and cup inclined, demonstrating that tilting of the cup may start in juveniles of similar ages. Articulation with the basal element is by radial ridges and depressions (Fig. 8, e2; see also Jäger 1991, figs. 1–4). However, the lower side of a large cup is concave and lacks ridges (Fig. 8, f2). Thus, the facet is similar to specimens figured by Loriol from the site of May-sur-Orne (1882; pl. 8, figs. 1d and 5b). However, the radial in pl.8, fig. 2b seems to have ridges on the lower side. The lower surface of basal elements commonly is concave and wider than the upper part that connects to the radial circlet (Fig. 8, d2). A number of radial circlets are fused with the basal element. Primibrachials and secundibrachials correspond to those figured by Loriol (1882) and Hess (2006, pl. 29, figs. 5–7), and their surface is granulated.
Remarks Radial circlets are fused to basal element or are provided with ridges and depressions, indicating rather strong articulation. This is in contrast to the specimens of Cotylederma docens, where the aboral element is thin-walled and often preserved isolated.
Suborder Cyrtocrinina Sieverts-Doreck 1952.
Superfamily Plicatocrinoidea Zittel 1879.
Diagnosis Cup consisting of fused basal circlet and circlet of 3–8 radials, commonly 4–6; radials may be partly or completely fused. Primibrachials 1 and 2 fused to axillary that carries unbranched arms, or joined by synostosis in lower Jurassic Plicatocrinus sulzkirchenensis, Sacariacrinus amadei n. sp., Praetetracrinus inornatus and P. doreckae, or muscular in Praetetracrinus kutscheri. Pinnules comprised of pinnulars that may be fused to form long spines or slightly curved rods. Column never fused to cup, columnals cylindrical or barrel-shaped to lenticular, facets with radiating marginal crenulae commonly arranged in groups or with irregular granules. Attachment by disk. (Modified from Hess in Hess and Messing 2011.)
Family Plicatocrinidae Zittel 1879.
Sacariacrinus Nicosia 1991.
Diagnosis Cup circular in section, comprised of 5–6-thick radials of variable height, with distinct sutures or fused, aboral surface smooth or weakly granulated, interradial embayments weak or absent; basal circlet compact, of variable height, may be fused with radial circlet. Radial articular facet rounded trapezoidal to elliptical, occupying full width of radial plate, inward sloping, and muscle fossae small and deep, surrounded by lip. Synostosis between primibrachials 1 and 2. First primibrachials of variable height. Secundibrachials joined by muscular articulation, proximal brachials bearing distinct pinnule sockets; distal brachials high, without pinnule sockets. Column unknown. (Modified from Hess in Hess and Messing 2011.)
Sacariacrinus amadei n. sp., Figs. 9 and 10.
Material MHNLM 2015.1.61–2015.1.80. Three basal circlets, two with five facets to radials, one with six; three radial circlets, two incomplete and attached to basal circlet, isolated radials, first and second primibrachials, secundibrachials. Samples 357, 358, 425, 540; early Toarcian (Tenuicostatum Zone).
Holotype MHNLM 2015.1.61. Radial circlet, Fig. 9a.
Paratypes MHNLM 2015.1.62 Incomplete radial circlet attached to intact basal circlet, Fig. 9b; MHNLM 2015.1.76, first primibrachial, Fig. 10h.
Etymology Species named in honour of both Wolfgang Amadeus Mozart, arguably the rock star among the composers of the Classical Era, and of Falco who paid tribute to Mozart’s subliminal rock’n’roll attitude with his song “Rock me Amadeus”.
Type locality and horizon Feuguerolles, early Toarcian (Tenuicostatum Zone).
Diagnosis Radial circlet comprised of 5–6 low compact plates that may be completely or partly fused; basal circlet low. Width of radial cavity about 30% of cup diameter. First and second primibrachials joined by synostosis, rarely weakly muscular. Proximal secundibrachials with pinnule sockets.
Description The holotype (Fig. 9a) is a rather low circlet comprised of five smooth radials with distinct sutures; the profile is circular with weak interradial embayments. Articulation to the basal circlet is by five synostosial facets that have scattered granules near the outer margin. The aboral surface is smooth. Radial articular facets are rounded trapezoidal and framed by a rim toward the radial cavity that narrows to the basal circlet. Aboral ligament fossa is wide and slightly outward-sloping; it occupies up to half the facet, and the ligament pit is elliptical. The adoral part of the facet with triangular interarticular ligament fossae is inward-sloping and separated from the aboral part by a distinct transverse ridge pierced by the axial canal. Muscle fossae are small, rimmed, and separated by a narrow notch. A strong lip separated by an interradial notch borders the facets from the radial cavity. The paratype (Fig. 9b) is an incomplete radial circlet of three tightly joined smooth pieces on top of an intact basal circlet. Radials originally numbered six, leading to hexagonal profile. Outline of the basal circlet is rounded hexagonal. A third, partly intact radial circlet (Fig. 10c) misses one radial out of five; it is rounded pentagonal in outline; and the radials are tightly fused, without interradial embayments. An isolated basal circlet (Fig. 9c) has the upper (distal) side with five facets to radials; the lower (proximal) side is concave and smooth. This ossicle demonstrates that the radial cavity is prolonged basally into the uppermost columnal. Most radials are sturdy and smooth aborally, but some are more or less granular (Figs. 9d, h, 10b). Whereas their upper facets are all similar, the lower facets to the basal circlet are somewhat variable, ranging from more or less angular (Figs. 9e, g, 10a, b) to nearly straight (Fig. 9d, f, h). Such a difference seems to indicate that articulation between basal and radial circlets varied in strength, and this is also demonstrated by preservation of radials still attached to the basal circlet. Radials are joined by smooth synostosial facets; the inner, adoral part is concave and of somewhat variable width. However, all radials are low and lack interradial extensions. A number of first primibrachials are assigned to the species. They vary considerably in height (Fig. 10g, h, k), but all have narrow food grooves, a proximal facet matching the radial facet, and a synostosial distal facet (Fig. 10g). The ossicles are weakly convex in profile, and the aboral side is smooth. Second primibrachials are lower (Fig. 10d, e); they are smooth aborally and have synostosial proximal and muscular distal facets (Fig. 10d). These extend adorally with rimmed muscle fossae, similar to those of the radials. A small second primibrachial has a weakly cryptosyzygial proximal facet (Fig. 10f). Secundibrachials vary widely in height (Fig. 10i, j, l). Their facets are muscular, and proximal brachials carry a large pinnule socket (Fig. 10i).
Remarks The present species is distinguished from S. altineri Nicosia (1991) by lower radials and basal circlet. Nicosia mentioned the occurrence of two morphotypes with thicker and thinner radials at the late Sinemurian–early Pliensbachian-type locality, his figures relate to the thick-walled type. Thick radials, primibrachials and a basal element from the upper Pliensbachian (Domerian) of Arzo, were ascribed by Hess (2006) to Sacariacrinus altineri, whereas thinner elements were designated S. cf. altineri. The thinner variety is similar to Praetetracrinus inornatus, although the Arzo radials are taller and the adoral incision with the muscle fossae extends more strongly downward (see Hess 2006, pl. 3, fig. 1b).
Family Tetracrinidae Nicosia 1991.
Diagnosis see Hess in Hess and Messing 2011.
Tetracrinus Münster, 1839.
Tetracrinus solidus n. sp., Fig. 11.
Material Only the holotype.
Holotype MHNLM 2015.1.81. Cup, Fig. 11.
Etymology L, solidus, for the firmly joined plates making up the cup.
Type locality and horizon Feuguerolles, sample 358, early Toarcian (Tenuicostatum Zone).
Diagnosis Cup conical, squarish, comprised of four radials fused with basal circlet to single piece with smooth latus. Radial articular facets nearly horizontal, occupying most of the distal part of the cup, no interradial sutures; aboral ligament fossa narrow with elliptical pit; interarticular ligament fossae large, separated by faint ridge from muscle fossae; and muscle fossae with distinct lip to radial cavity. Width of radial cavity 20% of cup diameter. Facet to column shallow concave and smooth, width of axial canal similar to that of radial cavity.
Description See diagnosis.
Remarks At first glance, the specimen seems to be comprised of only fused radials; but the lower, slightly concave facet suggests attachment to a column. Thus, it must be the lower (proximal) facet of a basal circlet. In the upper Jurassic Tetracrinus moniliformis (Münster), the cup articulates with the topmost columnal by symplexy with grouped radial crenulae (see Hess in Hess and Messing 2011). In the early Oxfordian, T. galei Hess (2014a) articulation is symplectial with reduced crenulae. The species co-occurs at sample 358 with Sacariacrinus amadei n. sp., whose radials are superficially similar. However, the cup of S. amadei is comprised of five somewhat bulging radials with a rather narrow base; radial articular facet of S. amadei is inward-sloping and bears small deep muscle fossae surrounded by a distinct rim. Tetracrinus solidus n. sp. is distinguished from the Upper Jurassic T. moniliformis by the higher, smooth cup, and narrow radial cavity; correspondingly, facets are wider. The Oxfordian T. galei differs from the present one by a wider radial cavity. The holotype of T. galei is a smooth conical cup with basal element and radial circlet separated by a distinct constriction; interradial sutures are indistinct, and thus, it approaches the new lower Jurassic species. Tetracrinus kocyigiti Nicosia (1991) from the upper Sinemurian/lower Pliensbachian of Turkey has 4–5 distinct basals carrying an inclined circlet of five radials.
Praetetracrinus Jäger 1995.
Remarks Jäger (1995) proposed the genus Praetetracrinus for Lower Jurassic cyrtocrinoids with tetramerous symmetry, fused basal circlet, high triangular and thin-walled radials and primibrachials connected by synostosis. Included species are P. doreckae Jäger 1995 (type species, lower Aalenian), P. inornatus (Simms 1989, Domerian–Toarcian), and P. kutscheri Jäger (1995, upper Toarcian–lower Aalenian). On a visit to the type locality of inornatus (Watton Cliff, Dorset), Jäger (1995, p. 10) noted the occurrence of two separate species, one being inornatus and the other, smaller species unnamed. According to Jäger, P. doreckae is closely related to P. inornatus, the two forms being parts of a phylogenetic series characterised by an increase in size.
Diagnosis See Hess in Hess and Messing 2011.
Type species Praetetracrinus doreckae Jäger, 1995.
Praetetracrinus inornatus (Simms, 1989), Figs. 12 and 13.
Plicatocrinus inornatus Simms, 1989, p. 86.
Praetetracrinus inornatus (Simms), Jäger 1995, p. 21.
Sacariacrinus cf. altineri Nicosia, Hess 2006, pl. 5, figs. 1, 2, 12
Material MHNLM 2015.1.82–2015.1.104. Numerous columnals, basal circlets, radials, and first and second primibrachials. The remains are common from the lower Toarcian Serpentinum Zone to the late Toarcian Variabilis Chronozone. A single radial is from the Tenuicostatum Chronozone (Fig. 13a), and a columnal is from the Aalenian (Fig. 12m).
Diagnosis Basal circlet fairly low, slightly concave, proximal facet with four groups of a few marginal crenulae, distal facet with four ridges separating slightly concave synostosial facets for articulation with the radials. Radial cavity wide; radials high, thin-walled, with interradial extensions; radial articular facet narrow, muscle fossae hardly extending downward. Columnals high to low, cylindrical or barrel-shaped; facets with crenulae in four groups or scattered, crenulae weakly developed in barrel-shaped columnals. (The diagnosis is adapted from Simms’ original description and includes the present material.)
Description The basal circlet is smooth and circular in outline, but may be rounded tetragonal in small specimens (Fig. 12c). The lower (proximal) facet is concave and has four groups of crenulae that do not reach the narrow axial canal. The upper (distal) facet has a central depression of somewhat variable width and four outward-sloping facets to radials; paired nerve canals are around the central depression (Fig. 12b, c). Thin topmost columnals have four groups of 2–3 crenulae (Fig. 12e, f); in one ossicle, the other facet is concave, suggesting connection to the basal circlet (Fig. 12f). Columnals are mostly smooth and cylindrical; facets are symplectial with short crenulae in four groups (Fig. 12g, h); and in some specimens, crenulae are reduced or scattered (Fig. 12i, m). Barrel-shaped columnals are less common, and their facets variable; some have weakly crenulated rims with areola and raised perilumen (Fig. 12k); and others have flat facets with a few scattered granules and a weak perilumen (Fig. 12j). However, facets such as those in Fig. 12j, k seem to match. Many cylindrical columnals have furrows or bite marks, discussed below. Radials are thin, aborally smooth and trapezoidal in profile; most have short interradial extensions. Facet to the basal circlet is straight in profile (Fig. 13a–f). Interradial facets are mostly narrow (Fig. 13a, b), but they may widen in part (Fig. 13c) or all of their height (Fig. 13d, f). The adoral side is concave and may have irregular sculpturing (Fig. 13d). Radial articular facet is a narrow ellipse. Aboral ligament is narrow and visible from the outside; muscle fossae are rimmed and separated by a narrow notch. They extend adorally pouch-like into the radial cavity but less so than in Sacariacrinus amadei n. sp. First primibrachials are rounded rectangular in outline and moderately high, and their surface is smooth. The food groove is narrow; it separates rimmed muscle fossae that slope inward to nearly half of ossicle height (Fig. 13g, 1). Distal facet is synostosial, with some marginal crenulae (Figs. 4, 13g). Axillary second primibrachials vary in height (Fig. 13i, h). Their proximal facets are synostosial; the distal muscular facets are separated by a process.
Remarks Nicosia (1991) compared Sacriacrinus altineri with Plicatocrinus inornatus Simms, which he ascribed to Sacariacrinus. As described by Simms, P. inornatus has thin-walled radials with interradial extensions. In our material, P. inornatus is represented in the Tenuicostatum Zone, the type horizon of Sacariacrinus amadei n. sp., by a single, thin radial (Fig. 13a) with straight lower suture and without interradial extensions; Sacariacrinus radials have more or less angled sutures for articulation to the basal circlet (Fig. 9e; see also Nicosia 1991, Fig. 13b). P. inornatus is remarkably similar to P. bathonicus Hess (2012). However, in the middle Jurassic species, the basal circlet is higher; radials are slightly keeled aborally and have a narrower base. At Feuguerolles, secundibrachials could not be assigned to this species with confidence. Such ossicles were described by Simms (1989, pl. 15, figs. 17, 20), and Jäger (1995, pl. 5) described secundibrachials of Praetetracrinus doreckae. In both cases, articulations are muscular, and the ossicles carry pinnule sockets.
Jäger reported deep furrows (“Rillen”) on columnals of Praetetracrinus doreckae (1995, pl. 1, figs. 17–20) and P. kutscheri or inornatus (pl. 6, fig. 8). In the present material, shallow scratch marks on columnals are rather common (Fig. 12g, h, k, m). On a Praetetracrinus radial (Fig. 13e) are scratch marks; similar traces also occur on columnals of Amaltheocrinus. The absence of skeletal growth around furrows or scratches suggests that the traces were made on dead ossicles lying on the sea floor.