Remark. Taxonomy and terminology, including references to authors, after Hess and Messing (2011)
-
Order Isocrinida Sieverts-Doreck, 1952
-
Suborder Pentacrinitina Gray, 1842
-
Family Pentacrinitidae Gray, 1842
-
Pentacrinites Blumenbach, 1804
-
Pentacrinites
ausichi n. sp., Fig. 3
Material. 6 columnals (one nodal), 5 cirrals, 3 brachials from Pont des Étoiles.
Holotype. Nodal, Fig. 3a, M10921.
Paratype. Internodal, Fig. 3b, M10922.
Etymology. In honour of William I. Ausich, foremost authority on fossil crinoids.
Type locality and horizon. Pont des Étoiles, La Voulte-sur-Rhône (Ardèche, France), Late Bajocian/Early Bathonian Parkinsoni/Zigzag Zones.
Diagnosis. Nodals and internodals of similar outline, but nodals higher than internodals; cirrus sockets centrally placed on latus, not displaced interradially; symplectial areolae narrow, elevated, straight-sided to elliptical.
Description. The columnals are pentagonal, with slightly concave latus. The only known nodal is slightly weathered, robust, rather high and has two similar facets with elevated, nearly straight-sided areolae. The large cirrus sockets occupy most of the latus; they are centrally placed and the cirral scar has a low transverse ridge slightly thickened at the ends. The large internodal (Fig. 3c) is low (height 2.2 mm), the areolae are straight-sided and have distinct crenulae on the elevated margins, the radial areas are nearly smooth but have a few tubercles towards the margin, and the latera are smooth. The smaller internodal (Fig. 3b) has elliptical areolae and radial areas with tubercles towards the latera that are ornamented by tubercles. In both internodals, the small lumen is surrounded by a small elevated perilumen. The three internodals not figured have diameter/height ratios of 9.5/2.6, 8.0/2.0 and 6.0/2.4 mm. The five cirrals are circular to slightly oval, and the ligament pits are nearly equal (Fig. 3e). One cirral ossicle (Fig. 3d) has one facet with a transverse ridge that matches a corresponding depression on the other facet. Similar cirrals are known from the proximal part of cirri of Pentacrinites dargniesi. A nearly circular, thin epizygal brachial has a proximal cryptosyzygial facet (Fig. 3f), while the other side is muscular with a pinnule socket. The cryptosyzygial facet resembles facets of P. dargniesi, supporting the assignment to a species of Pentacrinites. The two other brachials are similar in outline, but both facets are muscular, the distal one with pinnule socket.
Remarks. This species differs from the coeval Pentacrinites dargniesi Terquem & Jourdy by the presence of well-developed internodals whose size is similar to that of the corresponding nodal. Small internodals were not detected, but pluricolumnals would have to be available to verify this. De Loriol (1888) described three additional Bajocian species of Pentacrinites. Two of them, Extracrinus (=Pentacrinites) lorteti and Extracrinus (=Pentacrinites) sorlinensis, are from the Bajocian of Saint-Sorlin (Ain); they differ from P. dargniesi mainly by smooth brachials and cylindrical cirrals; the two species may well be conspecific. The columns from Saint-Sorlin are densely cirrated and, thus, seem to be devoid of larger internodals. The third species, Extracrinus (=Pentacrinites) babeaui, occurs at numerous locations in France, but is known only from columnals; the large nodals and the small internodals are quite similar to those of P. dargniesi.
-
Suborder Isocrinina Sieverts-Doreck, 1952
-
Family Isocrinidae Gislén, 1924
-
Subfamily Isocrininae Roux, 1981
-
Isocrinus
von Meyer in Agassiz, 1836
-
Isocrinus
nicoleti (Thurmann in Thurmann & Étallon, 1861), Fig. 4
1845 Pentacrinus Nicoleti, Desor, p. 5 (without description).
1861 Pentacrinus Nicoleti Desor; Thurmann & Étallon, p. 351 (first short description).
1879 Pentacrinus Nicoleti Desor; de Loriol, p. 139, pl. 15, figs. 34–36.
1887 Pentacrinus Nicoleti Desor; de Loriol, p. 165, pl. 154–161.
1972 Isocrinus
nicoleti (Thurmann); Hess, p. 65, pl. 21, figs. 1, 2, 4.
1975 Isocrinus
nicoleti (Thurmann); Hess, p. 55, pl. 7, fig. 4; pl. 11, 16.
Material. The bulk of the material consists of pluricolumnals from Pont des Étoiles where the species forms a crinoidal limestone. At La Pouza, the species is rare, and the columnals are smaller: one pluricolumnal of 6, one pluricolumnal of 5, one pluricolumnal of 4 (with nodal), one pluricolumnal of 3 (with infranodal), 7 pluricolumnals of 2 (2 with infranodal, 1 with nodal), 3 internodals, 2 nodals and 2 infranodals.
Diagnosis (column). Columnals are stellate to angular pentagonal, low, nodals slightly higher than internodals, cirrus sockets large, as high as nodal; latera of internodals are somewhat inflated between the margins, and inflated columnals may alternate with hardly inflated ones; noditaxis of 8 columnals.
Description. The material from Pont des Étoiles is largely composed of partly abraded pluricolumnals, but a number of well-preserved specimens are also available. They include complete noditaxes (Fig. 4a), incomplete noditaxes (Fig. 4b) and single columnals. The stellate columnals are low, and they alternate slightly in height and diameter. The latera are somewhat inflated between the margins; inflated columnals may alternate with hardly inflated ones (Fig. 4a2). The interradii are acute in smaller individuals (Fig. 4b), but become more rounded in larger specimens (Fig. 4a). The nodals are somewhat higher than the internodals, with cirrus sockets of equal height (Fig. 4a). Proximal nodals (Fig. 4c) are more strongly stellate than more distal nodals (Fig. 4d). The infranodals (top columnal of Fig. 4a) are slightly lower than the following internodals, and the proximal facet is cryptosymplectial (Fig. 4a1). All other columnal articulations are symplectial. The arrangement of the crenulae is typical of the genus, with similar radial and interradial crenulae.
Remarks. The figured specimens are from the Pont des Étoiles site; the few columnals from La Pouza have the same characters, but are smaller.
1865 Pentacrinus dumortieri Oppel, p. 317
1887 Pentacrinus dumortieri Oppel; de Loriol, p. 174, 182, pl. 162, figs. 1–8
Material. Pont des Étoiles. Pluricolumnals: one of 11 (with nodal and infranodal = noditaxis), one of 9 (with nodal and infranodal = noditaxis), one of 8 (with nodal and infranodal = noditaxis), two of 7 (one with nodal and with infranodal = noditaxis), one of 6 (with infranodal). La Pouza. Pluricolumnals: one of 8 (with nodal), two of 5 (one with infranodal), five of 3 (one with nodal), 14 of 2 (8 with nodal and 3 with infranodal, smallest has a diameter of 1 mm); 29 nodals, 73 infranodals, 173 internodals (smallest diameter = 0.8 mm), 1 topmost columnal.
Diagnosis. Columnals mostly low, stellate to pentagonal or pentalobate, with slightly concave latus, or circular; articular facets of large internodals with elliptical petals and adradial crenulae that may converge towards the lumen; adradial crenulae of smaller, circular internodals reduced to bands towards lumen; nodals with large cirrus sockets, not sunken, directed slightly upwards and surrounded by rim; width of cirral scar 50 % of nodal diameter, cirral scar with tubercle at each end; latera of internodals with median ridge that may be jagged or interrupted into segments or reduced to tubercles or knobs.
Description. The material from La Pouza includes columnals of all sizes and excellent preservation (Fig. 5). Among them are small, more or less circular nodals and internodals with adradial crenulae reduced to V-shaped element (Fig. 5d, f, g). The median ridge on the latera may be sharp and continuous (Fig. 5c, i, j), or interrupted with prominent processes (Fig. 5b), or the ridge may be modified into granules or knobs (Fig. 5a, d–h). The pluricolumnal figured combines these features (Fig. 5a2); the top columnal has a continuous ridge, the middle one a ridge interrupted and the lower one a band of tubercles.
Remarks. The species name, dumortieri, was by Oppel (1865) and without description. The species was first characterized by de Loriol (1877), who mentioned noditaxes varying between 9 and 13. In the material from Pont des Étoiles, the noditaxis varies between 7 and 11. The material from La Pouza is more disarticulated and has not furnished a pluricolumnnal consisting of a noditaxis. Isocrinus dumortieri is easily distinguished from I. nicoleti by the prominent median ridge on the latus of most columnals, including juveniles.
-
Subfamily Balanocrininae Roux, 1981
-
Balanocrinus Agassiz in Desor, 1845
-
Balanocrinus dumortieri
de Loriol
1877, Fig. 6
1871 Pentacrinus pentagonalis (Goldfuss); Dumortier, p. 46, pl. 5, figs. 1–3.
1887 Balanocrinus dumortieri
de Loriol, p. 324, pl. 187, figs. 3–8.
1996
Balanocrinus dumortieri
de Loriol; Klikushin, p. 117, pl. 8, figs. 1–2.
2007 Balanocrinus dumortieri
de Loriol; Charbonnier et al., figs. 10e–f.
Material. Pont des Étoiles: one pluricolumnal of 3. La Clapouze: 4 internodals. Chénier Ravine: 3 internodals. La Pouza (collected by the author): 8 pluricolumnals: one of 8 (with nodal in the middle), two of 6 (one with infranodal), one of 4, two of 3 (one with infranodal), two of 2 (one with nodal) and 10 internodals. La Pouza (Beds 1–3): 2326 internodals, 231 nodals (the smallest with a diameter of 0.7 mm), 259 infranodals; and the following pluricolumnals: one of 6 (with nodal), two of 5 (one with nodal), 9 of 4 (4 with nodal), 15 of 3 (2 with infranodal), 100 of 2 (15 with nodal, 7 with infranodal).
Diagnosis. Facets of internodal columnals circular to subcircular to weakly pentalobate or rounded pentagonal, with rather long marginal crenulae; crenulae commonly V-shaped adradially, where size of crenulae decreases towards the lumen, or crenulae are modified into elevated bands; latera concave and smooth in circular columnals, while in pentalobate columnals commonly a tubercle in each radius; latus separated from facet by sharp ridge; nodals somewhat higher than internodals, with large cirrus sockets nearly as high as nodal, separated by tubercle.
Description. The columnals are mostly circular, tending to slighly pentalobate or rounded pentagonal. The facets of internodals have rather pronounced marginal crenulae that are commonly V-shaped adradially (Fig. 6a1, b). The radial bands of crenulae may be flat (Fig. 6a1, b) or elevated (Fig. 6d, e1). The distinct marginal ridges are thickened in rare cases (Fig. 6f). Distal facets of nodals and proximal facets of infranodals are cryptosymplectial; Fig. 6g shows the lower (distal) facet of a tetramerous nodal with stereomic growth sealing the axial canal, possibly at the end of the column. Tetramerous columnals occur occasionally (Fig. 6h). Juvenile columns are essentially similar to adult ones (Fig. 6e). The smallest nodal has a diameter of 0.8 mm, and the smallest internodal of 0.5 mm. The latera of circular columnals are smooth, but those of pentalobate outline commonly have a rounded tubercle at each radius. This is the commonest isocrinid at La Pouza, by far represented by numerous pluricolumnals and columnals. No intact noditaxis has been found by the author, but can be estimated from the number of nodals or infranodals and internodals at approximately 11 columnals. De Loriol (1887, p. 325) mentions a noditaxis of 9 columnals.
Remarks. The species is easily recognized by the concave latera of the internodals, separated from the facets by a sharp ridge. Brachials assigned to this species include distinctive syzygies (Fig. 9b–d). Syzygies are not uncommon in secundibrachials of Balanocrinus species (Hess 2006, pl. 25, figs. 10, 12–14). The present brachials also resemble brachials from the Albian of England (Hess & Gale 2010, fig. 6x) that were unassigned, but may have belonged to Balanocrinus smithi Hess.
1887 Balanocrinus Pacomei
de Loriol, p. 318, pl. 186, figs. 1–6.
Material. Pont des Étoiles. 22 pluricolumnals: one of 15 (without nodal or infranodal), two of 8, two of 7, four of 6 (one with nodal), two of 5, three of 4, four of 3, four of 2 (one with nodal); one nodal and 11 internodals. At La Pouza, the species is rare: one pluricolumnal of 2 (without nodal or infranodal), a single internodal and a single nodal.
Diagnosis. Columnals circular, with slightly convex, smooth latera, facets with short marginal crenulae and narrow elevated granular radial bands; nodals with large cirrus socket nearly as high as nodal, cirral scar with narrow transverse ridge interrupted by pore.
Description. The columnals are all similar. A pluricolumnal of 9 has a nodal distally, and the facet of the proximalmost internodal is symplectial. This indicates a noditaxis of more than 10 columnals, which is confirmed by a pluricolumnal of 15 internodals with an infranodal on top (Fig. 7d). Tetramerous columnals occur occasionally (Fig. 7d).
Remarks. The species is easily distinguished from the other species of the genus by the more or less convex latera and the adradial crenulae developed into elevated bands.
1850 Pentacrinus inornatus
d’Orbigny, p. 891.
1887 Balanocrinus inornatus
d’Orbigny, de Loriol, p.311, pl. 184, figs. 3–9.
1911 Balanocrinus inornatus
d’Orbigny, Boule, p. 111 (pl. 22, fig. 12, published 1911).
1912 Balanocrinus inornatus
d’Orbigny, Lissajous, p. 173, pl. 18, fig. 32
1927 Balanocrinus inornatuss (d’Orbigny), Valette, p. 27.
Material. Pont des Étoiles: one pluricolumnal of 2 with nodal (Fig. 7b), one pluricolumnal of 3 (Fig. 7a), four pluricolumnals of 2 (Fig. 7c). La Pouza: one internodal. Chénier Ravine: three internodals.
Diagnosis. Large species, columnals high, cylindrical, with smooth latus; facets with short marginal crenulae and weak radial ridges, so that internodal articular surface may resemble cryptosymplexy; cirrus sockets hardly sunken, half as high as nodal, width of cirral scar approximately 40 % of nodal diameter, transverse ridge modified into two isolated weak tubercles.
Description. The columnals are all similar. The ratio of height to diameter varies from approximately half in adult specimens to one in the juvenile specimen (Fig. 7c).
Remarks. The species was first mentioned by d’Orbigny (1850), and described and figured in some detail by de Loriol (1877) on the basis of material from the Oolithe blanche (now considered lower Bathonian) of Normandy, Creuse and Orne. D’Orbigny’s type, a pluricolumnal of 6 without a nodal, is from Guéret (Sarthe), and it was figured by Boule (1911) in the Types du Prodrome. According to de Loriol (1877), the column seems to be pentagonal near the cup; more distally, it is cylindrical with circular facets. The species was mentioned or described from several locations of France and Spain. Lissajous (Lissajous 1912, pl. 18, fig. 32) figured a small pluricolumnal from the Bajocian Parkinsoni Zone of Mâcon. The species was described, but not figured, by Valette (1927) from the upper Bajocian of Catalogne (Tivenys). Balanocrinus inornatus is easily distinguished from the two other species of Balanocrinus occurring at Pont des Étoiles by the smooth, compact nature of the cylindrical columnals. Valette mentioned that the articular facets are commonly indistinct (“la facette articulaire de cette espèce est assez souvent peu accentuée, et semble parfois disparaître”). Smooth circular columnals are distinctive for B. subteres (Münster in Goldfuss), the type species of the genus from the Oxfordian, but the radial ridges are more prominent and have larger crenulae; the cirral scars are more pronounced.
Remains of isocrinids that cannot be assigned to a given species
Isocrinid cirrals
La Pouza (1-3): 136, 1 pluricirral of four. The cirrals are elliptical to nearly circular in section and vary from short to long, with concave body. Facets are similar and synarthrial. The cirrals are mostly smooth, but short, circular cirrals have fringed borders. Assignment to a given species is not possible, although the ornamented ossicles may have belonged to Isocrinus dumortieri.
Isocrinid brachials (Figs. 8, 9)
The material isolated from the from the La Pouza samples yielded a considerable number of isocrinid cup plates and brachials with distinctive characters. Among them are a few radials and primibrachials, but mainly secundibrachials with different types of articulation facets. Two major groups may be distinguished.
Ossicles with smooth latus, and brachials more or less circular in outline, except elongate distal secundibrachuials which are elliptical
Most of the ossicles may be tentatively assigned to Balanocrinus dumortieri
de Loriol. Not only is this species the prominent isocrinid at La Pouza, but the shape of the secundibrachials with muscular facets resembles those of other species of the genus (Hess, research in progress). In addition, symmorphies and especially syzygies also occur in Balanocrinus.
Radials: 12 (Fig. 8a), the facet to the basals (Fig. 8a1) indicates that the basals were in contact, a character typical of Balanocrinus. The aboral surface is smooth in most cases, but verrucose in two radials.
First primibrachials: 35. The distal facet is synarthrial or cryptosynarthrial.
Axillaries: Sixty-one rather high axillaries with a proximal synostosial or symmorphial facet appear to be second primibrachials (Fig. 8g); two low axillaries with proximal synarthry certainly are second primibrachials, matching the first primibrachials in Fig. 8c; 118 axillaries with muscular proximal facet are secondary axillaries (secundibrachials). True isocrinids have primibrachials articulated by synarthries as in Fig. 8c. The rather numerous high axillaries with smooth ligamentary proximal facet (Fig. 8g) cannot be classified with certainty at present.
Secundibrachials. (1) The large majority of secundibrachials, 3,872 in number, have two muscular facets, the distal with pinnule socket (Fig. 8h). Most of these ossicles are thought to belong to Balanocrinus dumortieri. (2) Secundibrachials with syzygy: 149, 49 of which are hypozygal (proximal facet muscular, distal facet syzygial) and 100 are epizygal (proximal facet syzygial, distal facet muscular with pinnule socket (Fig. 9b–d). Syzygial brachials generally are low. Syzygies are common in comatulids, but remains of those are so rare that such assignment can be ruled out. Syzygies are not known from Isocrinus, but may occur in Balanocrinus, the common isocrinid at La Pouza. (3) Secundibrachials with cryptosyzgy or synostosis developed as symmorphy: hyposymmorphial (proximal musculer facet, distal cryptosyzygy), 82; episymmorphial (proximal cryptosyzygial, distal muscular with pinnule socket), 105 (Fig. 8b). Symmorphies (Fig. 8b) are characteristic of Isocrinus, and weak symmorphies or cryptosyzygies (Fig. 9e) are found in Balanocrinus. (4) Mostly rather high secundibrachials, with flat cryptosyzygy or synostosis that may approach symmorphy (the distinction is not sharp in some cases): muscular facet (proximal) without pinnule socket, 116 (Fig. 9e); muscular facet (distal) with pinnule socket, 190. Ossicles of this group may be assigned to Balanocrinus. (5) Secundibrachials with both facets synostosial or cryptosyzygial (Fig. 9f): 2. Ossicles in group 5 seem to belong to the same species as those in group 4.
Pinnulars: 27. The pinnulars are of different length, laterally compressed and triangular in section. They cannot be assigned to a specific isocrinid.
Ossicles with verrucose or granular latus
Secundibrachials belonging here are mostly verrucose or have a jagged edge, but some are also smooth. They are generally low and wide, while some are more or less rectangular (Fig. 8f), orally prolonged (Fig. 8e, j) or trapezoidal (Fig. 8i, k). Their assignment is doubtful, but they may belong to Isocrinus dumortieri
de Loriol, a species characterized by ornamented columnals.
Radials: 2.
First primibrachials: 5 (Fig. 8c, d)
Second primibrachials: 6 (low)
Secundibrachials with proximal cryptosyzygy and distal muscular facet with pinnule socket: 11 (Fig. 8e); secundibrachials with proximal muscular facet and distal cryptosyzygy or syzygy without pinnule socket: 15; secundibrachials with two cryptosyzygial or synostosial facets: 1; secundibrachials with two muscular facets, the distal one with pinnule socket: 300 (Fig. 8f, i, k).
-
Order Comatulida A. H. Clark, 1908
-
Suborder Comatulidina A. H. Clark, 1908
-
?Superfamily Paracomatuloidea Hess, 1951
-
?Family Paracomatulidae Hess, 1951
-
Singillatimetra n. g.
Etymology. From singillatim (latin, single) and metra, the suffix commonly used for comatulids; the centrodorsal is composed of a single, disc-like element.
Diagnosis. Centrodorsal low, asymmetrical in outline; 5 bulging cirrus sockets arranged irregularly; no radial cavity or axial canal; aboral and adoral sides similar, weakly sculptured, on aboral side irregular tubercles and weak radial impressions without crenulae, on adoral side narrow interradial bands with short crenulae for articulation to basals.
Type species. Singillatimetra inordinata n. sp.
Remarks. This peculiar centrodorsal has properties of the Paracomatuloidea, but consists of only one piece. The lack of an axial canal indicates that it was not part of a centrodorsal composed of several pieces. The arrangement of the cirrus sockets, offset to either side of the radial midline, and the sign of crenulae on the adoral side suggest a paracomatuloid relationship. The form is tentatively assigned to this superfamily.
Material. Only the holotype is available.
Holotype. Centrodorsal, diameter 2.6 × 3 mm, height 0.9 mm, M10838.
Etymology. After the irregular arrangement of the cirrus sockets on the centrodorsal.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. See genus (monotypic).
Description. The centrodorsal is asymmetrical in outline, with five bulging cirrus sockets offset from the radial midlines. The cirral scar is unsculptured, except for a weak transverse ridge in the upper part separating an upper third at an angle of 120° from a lower two-thirds. Both facets are similar and weakly sculptured, without radial cavity or axial canal. The presumed aboral side has some irregular impressions and tubercles, the presumed adoral side shows five rather regular narrow bands flanked by short crenulae or tubercles This structure is thought to have been articulated to basals.
-
Superfamily Solanocrinitoidea Jaekel, 1918
-
Family Solanocrinitidae Jaekel, 1918
-
Solanocrinites Goldfuss, 1829
-
Solanocrinites
voultensis n. sp., Fig. 11c
Material. Only the holotype is available.
Holotype. Centrodorsal, diameter 4.2 × 4.6 mm, height 2.4 mm, M10844.
Etymology. After the area of the type locality.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Centrodorsal columnar, aboral apex flattened, with narrow central depression and interradial ridges; cirrus sockets arranged in somewhat irregular 15 vertical columns of two to three rows, the five columns of each side separated by interradial ridges; narrow ridges for basal rods on the adoral side separated by weak irregular furrows, and the centrodorsal cavity a tenth of centrodorsal diameter.
Description. The centrodorsal is columnar and weakly pentagonal. Aboral and adoral sides are similar, but narrow bands for articulation to the basal rods and a moderately deep, narrow centrodorsal cavity (Fig. 11c3) leave no doubt about the nature of the upper facet. In contrast, the aboral side has five narrow interradial bands with slightly concave profile, three of the interradial sections are raised in folds with sockets at the end alternating with irregular furrows (Fig. 11c1). The five sides are covered by more or less circular cirrus sockets separated by interradial ridges. On each side, the sockets are arranged in five columns of mostly two to three rows; the sockets are displaced against each other, so that some protrude onto the aboral side, causing an irregular relief. The scars are unsculptured, but for a faint transverse ridge. The adoral side is dominated by the ridges for the narrow basal rods; between the ridges are shallow furrows, but also somewhat elevated areas, corresponding to slightly protruding cirrus sockets. The radial cavity is narrow.
Remarks. Assignment of the centrodorsal to Solanocrinites is unproblematic. In the similar genus Palaeocomaster, the cirrus sockets are arranged in irregular marginal circles without being separated by interradial ridges. This character also separates S.
voultensis n. sp. from Palaeocomaster cf. guirandi (described below). Palaeocomaster
schlumbergeri (de Loriol 1888, Bigot 1938) from the Bathonian of Calvados has a low, conical centrodorsal that may have variable interradial ridges (atypical of the genus), and there are only two columns of sockets in irregular rows of one to three. In addition, P.
schlumbergeri has distinct impressions on the adoral side for the basals, which protrude on the outside and are united centrally, giving a star-like appearance. Palaeocomaster stellatus Gislén (1924) from the Bathonian of England is similar to P.
schlumbergeri, but has a flat aboral side with a stellate impression.
-
Palaeocomaster Gislén, 1924
-
Palaeocomaster cf. guirandi (de Loriol, 1889), Fig. 10c
Material. One centrodorsal. M10837.
Description. The centrodorsal is flattened, nearly circular, with a diameter of 4.0 mm and a height of 1.5 mm. The circular, prominent cirrus sockets are alternating and arranged in two irregular rows not interrupted by interradial ridges. The aboral side is somewhat weathered, cirrus free, irregular and has a central cavity of similar diameter (0.5 mm) as the centrodorsal cavity on the adoral side; smaller pits are due to weathering. The adoral side shows some flat interradial ridges for the basals.
Remarks. De Loriol (1888, p. 467; pl. 216, fig. 5) described a single centrodorsal from the Oxfordian of Le Pontet near Saint-Claude (France) under the name of Antedon guirandi. He also described a centrodorsal with cup from the same locality as Actinometra guirandi (de Loriol 1888, p. 535; pl. 227, fig. 2) without making reference to the earlier. Gislén (1924, p. 142) chose the latter specimen as type of guirandi, type species of Palaeocomaster Gislén, obviously considering the two specimens conspecific. The single centrodorsal has a diameter of 9 mm, whereas the centrodorsal with cup has one of only 3 mm. Both specimens have a low, flat centrodorsal, sculptured on the aboral side of Antedon guirandi, but smooth in Actinometra guirandi. Cirrus sockets of the latter are circular and surrounded by a rim, whereas they are more elliptical with a transverse ridge on the larger centrodorsal. Number and arrangement of sockets are similar in the two specimens. The present centrodorsal differs from that described by de Loriol (1889, pl. 216, fig. 5) by smooth cirrus sockets and a wide centrodorsal cavity on the adoral surface (narrow in de Loriol’s specimen). However, this difference and also different sculpturing may be due to weathering of the present specimen.
Material. Cup with centrodorsal (holotype), centrodorsal with attached basals (paratype).
Holotype. Cup with centrodorsal; largest diameter 5 mm, height 5 mm, height of centrodorsal 1.5 mm; M10842, Fig. 11b.
Paratype. Centrodorsal with basals; diameter 3 mm, height approximately 2 mm; M10840, Fig. 11a.
Etymology. In honour of Charles G. Messing for his work on living comatulids.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Centrodorsal low discoidal, irregular in shape, aboral apex smooth, interradial angles not produced; cirrus sockets crowded, in irregular on to four marginal cycles; five narrow basals hardly visible from outside, united centrally around narrow centrodorsal cavity; surface of radials not exposed, overhanging; radials with wide, steep facets, interarticular ligament fossae triangular and distinct, adoral muscle fossae high, separated by median notch; radial cavity moderately large.
Description. The centrodorsals of the two specimens vary in size; the centrodorsal of the holotype is reduced in diameter and height in comparison with the paratype. The centrodorsal is of irregular shape. Seen aborally, radial pairs of sockets with their base are fused and raised in folds, interrupted by more or less pronounced radial furrows, but this arrangement is somewhat irregular. The cirrus sockets vary in size and are unsculptured. The basals are narrow and united centrally, resembling the spokes of a wheel. They are visible from the outside as small knobs. The radial circlet is higher than the centrodorsal and does not display a free surface, which, thus, is overhanging. The steep radial articular facets are divided into three parts of roughly equal size, (1) an aboral ligament area with rather shallow fossa, (2) a middle part around the wide elliptical axial canal with transverse ridge below and lateral ridges containing triangular interarticular ligament fossae and (3) an upper part dominated by the muscle fossae separated by a deep notch. The radial cavity is moderately large.
Remarks. Palaeocomaster
messingi n. sp. differs from P.
schlumbergeri (de Loriol) by a much higher radial circlet with large axial canal and a centrodorsal of irregular shape with smooth aboral apex. In addition to the holotype of P.
schlumbergeri from Calvados, numerous remains have become available from a site in the same department described by Bigot (1938). Bigot figured centrodorsals of more conical shape, with rather narrow aboral apex and cirrus sockets extending to near the apex, especially in smaller individuals. As in de Loriol’s holotype, the radial circlet is low compared with the present material, and the free surface of the radials is visible band-like above the centrodorsal. Topotype specimens in the Basel Museum, among them a well-preserved centrodorsal with cup and base of arms (M11034), display the same characters and are easily distinguished from the present specimen. The present material invites comparison with the Lower Jurassic (Hettangian) Palaeocomaster
styriacus Kristan-Tollmann, the oldest comatulid with a centrodorsal composed of a single element. This species and the Pliensbachian P. morierei
de Loriol (see Hess 2006) have centrodorsals composed of partly fused but distinct tubes that widen outwards to the cirrus socket. In P. messingi n. sp. such tubes are still visible, but fusion is more pronounced, and this is also true of the Upper Jurassic P. guirandi. Such morphology of the centrodorsal differs from that of Paracomatula species with rather compact centrodorsal, fused from a number of disc-like columnals. Singillatimetra inordinata n. g., n. sp., which may be a paracomatulid, also has a disc-like compact centrodorsal, without discrete “cirrus tubes”. Such differences suggest that morphology of centrodorsals in early comatulids is more complex than previously thought.
Andymetra n. g.
Diagnosis. Centrodorsal hemispherical, apex with only small cirrus-free area; cirrus sockets crowded, in several irregular rows, deep and hardly sculptured; adoral side with weak impressions of basals, centrodorsal cavity narrow, a tenth or less of centrodorsal diameter.
Etymology. In honour of Andy (Andrew) S. Gale for his contributions to the study of echinoderms; and -metra, suffix commonly used for comatulids.
Type species. Andymetra galei n. sp.
Remarks. The new genus shares the narrow centrodorsal cavity with the other genera of the family, but is distinct for its convex, hemispherical centrodorsal and the crowded cirrus sockets. These are arranged in irregular rows, not forming columns, as in Palaeocomaster, a genus with more or less flat aboral apex.
Other species. Antedon ladoixensis
de Loriol (1888, p. 450; pl. 211, fig. 1) from the Bathonian of Côte-d’Or, France) and also reported from Calvados under the genus name Glenotremites (Bigot 1938).
Material. Only the holotype is available.
Holotype. Centrodorsal, diameter 3.7 mm, height 2 mm, M10841.
Etymology. Named after A. S. Gale who collected the material.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Centrodorsal nearly hemispherical, cirrus sockets crowded, in as many as four irregular rows.
Description. The centrodorsal is nearly hemispherical in profile and only the apex is devoid of cirrus sockets. These are crowded, deep and hardly sculptured; they occur in several, irregular rows, and columns cannot be distinguished. The adoral surface shows five weak flat ridges, some with faint crenulae; their shape and arrangement suggest that they served for reception of basal rods. The centrodorsal cavity is narrow.
Remarks. The present species has a more hemispherical centrodorsal than A.
ladoixensis, which was assigned by Gislén (1924, p. 126) to the group of Glenotremites
morierei (de Loriol); this Lower Jurassic species is now placed in Palaeocomaster (see Hess 2006, p. 59). The centrodorsal of A.
ladoixensis (de Loriol 1888) is lower (diameter 4.5 mm, height 1.75 mm), with a more flattened apex. Bigot’s smaller centrodorsal (1938, pl. 4, fig. 21) is also low (diameter 2 mm, height 0.5 mm).
-
Order Millericrinida Sieverts-Doreck, 1952
-
Family Apiocrinitidae d’Orbigny, 1840
-
Apiocrinites sp., Fig. 23e
1871 Millericrinus; Dumortier, p. 46, pl. 5, figs. 4–6.
Material. La Pouza: two pluricolumnals of 4, one pluricolumnal of 2, 17 columnals (6 broken). La Clapouze: two pluricolumnals (one of 2 and one of 5 columnals).
Description. All columnals have straight latera and facets with rather strong radiating crenulae that commonly bifurcate near the margin (Fig. 23e). Most columnals have a slope between the crenularium and the lumen. The height/diameter ratio of columnals from La Pouza varies between 21 and 44 % in larger columnals, but reaches 70 % in small columnals of 1.3 and 3.8 mm in diameter. The lumen of larger columnals varies between 9 % and approximately 21 % of diameter; it reaches 40 % of the diameter in the smallest columnal (diameter 1.3 mm). The two pluricolumnals from La Clapouze with a diameter of 8.5 and 7.8 mm, respectively, are composed of low columnals with slightly convex latera; the lumen is relatively narrow at 10 % of the diameter.
Remarks. The columnals from the two sites are thought to belong to a single species despite the differences. Variable width of lumen is common in apiocrinitids. For example, width of the lumen in the Late Jurassic Apiocrinites
roissyanus (d’Orbigny) from a single locality (Hess 1975, pl. 22, fig. 15–16) varies between 17 % (column diameter 9 mm) and 38 % (column diameters 5.3 and 8 mm). Assignment to Apiocrinites is tentative and is based on the occurrence of bifurcate and somewhat coarser crenulae. Such features are less common in otherwise similar columns of Liliocrinus Rollier (see Hess 1975, pl. 22, fig. 4–6). The large pluricolumnal (diameter 12 mm) figured by Dumortier (1871, fig. 5–6) from La Clapouze has a narrow lumen and strongly bifurcate crenulae (“Les lignes rayonnantes soint fortement dichotomes…”, Dumortier 1871, p. 47), and is similar to the present material.
-
Order Cyrtocrinida Sieverts-Doreck, 1952
-
Suborder Cyrtocrinina Sieverts-Doreck, 1952
-
Superfamily Eugeniacrinitoidea Zittel, 1879
-
Family Eugeniacrinitidae Roemer, 1855
-
Lonchocrinus Jaekel, 1907
-
Lonchocrinus
dumortieri (de Loriol
1882), Fig. 12a–c
1871 Eugeniacrinus caryophyllatus (Goldfuss); Dumortier, p. 48, pl. 5, fig. 12–13 (cup).
1882 Eugeniacrinus
Dumortieri
de Loriol, p. 132, pl. 14, figs. 1–12 (cups, second primibrachials, columnals).
1891 Eugeniacrinus
Dumortieri (de Loriol); Jaekel 1891, p. 587, fig. 5 (second primibrachial); p. 647.
2007 Eugeniacrinus
dumortieri (de Loriol); Charbonnier et al., fig. 9a (cup).
2007 Lonchocrinus sp.; Charbonnier et al., fig. 9b–c (second primibrachials).
Material. Pont des Étoiles: 2 cups. La Pouza: 8 cups, 4 s primibrachials. Chénier Ravine: 4 cups. La Clapouze: 68 cups, 9 s primibrachials.
Description. The cup has a cylindrical proximal and a widened upper part and it consists of radials with distinct interradial processes. The second primibrachials are axilllary, with a prominent spine-like process separating small facets for the secundibrachials (Fig. 12b). In the material from La Pouza are two axillaries with blunted tip curved inward (Fig. 12c).
Remarks. The species is most common at La Clapouze. It is easily distinguished from Eugeniacrinites
cariophilites
von Schlotheim by the shape of the second primibrachials and the different profile of the cup.
-
Family Phyllocrinidae Jaekel, 1907
-
Phyllocrinus
d’Orbigny
1850
-
Phyllocrinus fenestratus (Dumortier
1871), Fig. 12d–e
1871 Eugeniacrinus fenestratus Dumortier, p. 49, pl. 5, fig. 14–16 (cups).
1882 Phyllocrinus fenestratus (Dumortier); de Loriol, p. 106, pl. 17, figs. 3–9 (cups).
Material. The species has been found by the author only at La Clapouze where it is even more common than Lonchocrinus dumortieri. In fact, some rock samples are literally filled with the cups of this species. There are 96 isolated cups and several rock fragments containing approximately 35 cups. Dumortier (1871) also reported the species from La Pouza and Rians (Var), and de Loriol (1882) reported it from the area of Aix.
Description. The cups are circular in the lower part, increase in diameter towards the articular facets and are prolonged interradially into high processes of triangular section (see Hess & Messing 2011, fig. 89, f). The articular facets are deeply sunken between the processes. The facet to the column is small and deeply concave in most specimens. A specimen preserved on rock has exceptionally high processes and a rather large facet to the column (Fig. 12e). Variations include a rather broad cup with bulging radials and small facet to the column (Hess & Messing 2011, fig. 89, d–f), slender cups with small column facet, the most common form at La Clapouze; one of such specimens has a juvenile cup attached (Fig. 12d) and cups with processes curved more or less outwards (Dumortier 1871, pl. 5, fig. 14; de Loriol 1882, pl. 17, fig. 4).
Remarks. In the material from La Pouza sampled by A. S. Gale, no cup of this species has been found. This is rather surprising, given the report by Dumortier. Perhaps, Dumortier’s specimens came from parts of the outcrop rich in sponge remains, similar to the Clapouze site, whereas most of the present material is from the claystone beds.
1882 Phyllocrinus colloti
de Loriol, p. 106, pl. 18, fig. 4–9.
2007 Phyllocrinus colloti
de Loriol; Charbonnier et al., fig. 10b–c.
Material. Pont des Étoiles: 3 cups. La Pouza: 1 cup, Chénier Ravine: 4 cups (one with 9 and one with 10 columnals).
Description. This is the only cyrtocrinid from the area with at least one, but commonly several, columnals attached to the cup. The majority of specimens are from the Chénier Ravine locality, and it has not been found in the residues of the La Pouza clay beds. The cup is smooth and considerably higher than wide; it is circular in section and consists of commonly fused radials. The articular facets for the primibrachials are wide for a member of the genus, the interradial processes are strong at the base, moderately high and triangular in section. There is a gradual transition to the first columnal whose facet is rather wide, but is never exposed because of fusion. The cup in Fig. 13a is attached to three fused columnals. The column may have straight latera, but columnals may be slightly convex (Charbonnier et al. 2007, fig. 10b–c). Column facets have short marginal crenulae (Fig. 13a2).
Remarks. Charbonnier et al. (2007, fig. 10b–c) figured two specimens from Chénier, one with a short column and the other with a long one, similar to the material collected by the author. The specimens figured by de Loriol (de Loriol 1882, pl. 18, figs. 4–9) are from Rians (Var) and do not differ from those of the Ardèche area.
Material. Pont des Étoiles: 3 cups, La Pouza: 14 cups.
Holotype. Cup, diameter and height 4 mm, M10854, Fig. 13b.
Etymology. After the type locality.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Cup small, pentalobate in section, with interradial furrows; facet to column sunken, with short marginal crenulae and wide axial canal; radial cavity narrow and deep; radials strongly bulging radially, with moderately high interradial projections, triangular in section; facets with small aboral ligament fossa and deep, circular muscle fossae.
Description. A number of small, low cups differ from other species of Phyllocrinus from the Ardèche. They have outward bulging radials, which are slightly keeled with deep interradial furrows in the smallest specimen (diameter 2 mm, height 1.6 mm; Fig. 13e), but are commonly rounded (Fig. 13b, d); the largest specimen is somewhat flattened (Fig. 13c). Sutures between the radials are distinct and sunken. The facets lie between triangular interradial projections. The facet to the unknown column is deeply sunken in the smallest specimen, larger and moderately sunken in the holotype, and nearly flush with the aboral side of the cup in the largest cup. The radial cavity is deep, extending to near the bottom.
Remarks. The present species is part of a series of small Phyllocrinus characterized by a nearly spherical cup with rather small interradial processes and bulging radials. The group includes P. gauthieri
de Loriol (1882, pl. 17, fig. 2–3) from the Bathonian of Claps (Bouches-du-Rhône), P. alpinus (d’Orbigny) described by de Loriol (1882, p. 18, fig. 2) from the Oxfordian of Chaudon (Basses-Alpes) and P. gibbosus
de Loriol (1882, pl. 18, fig. 3) from the Oxfordian of Crussol (Ardèche). Phyllocrinus
voultensis n. sp. is closest to P. alpinus, known from a unique specimen with a diameter of 2.5 mm and a similar height (a height of 3.5 mm was given by de Loriol, but the figure shows a height similar to the diameter). The radials are keeled, and the cup is nearly pentagonal in outline. De Loriol’s specimen is also distinguished from P.
voultensis n. sp. by a wider aboral ligament fossa.
Diagnosis. Cup flat, shield or dish-like, composed of thin radials without bulges, radial cavity deep and wide, radial articular facets wide, separated by low, leaf-like interradial processes; facet to column small.
Etymology. After the shield- or dish-like cup.
Type species. Scutellacrinus tenuis n. sp.
Remarks. The cup combines the wide articular facets and interradial projections of a eugeniacrinitid with the generally slender build and small columnal facet of a phyllocrinid. The wide articular facets, not typical of phyllocrinids, obviously are a consequence of the dish-like geometry of the cup. The genus is tentatively assigned to the Phyllocrinidae.
Material. Only the holotype is available.
Holotype. Cup, diameter 4.5 mm, height 2.7 mm, M10839
Etymology. After the thin radials.
Type locality and horizon. Late Bajocian/Early Bathonian (Parkinsoni/Zigzag Zones), Pont des Étoiles, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. See genus (monotypic).
Description. The cup is wide and low. The articular facets for the primibrachials occupy most of the width and extend into the cavity; the facets are almost entirely occupied by the large ellipitical muscle fossae, which are separated by a narrow notch. The aboral ligament is reduced to a small pit and interarticular ligament fossae appear to be absent. The interradial processes are leaf-like, with rounded tips; their sides are flanked by the muscle fossae. The wall of the radial cavity is evenly sloping and is nearly smooth (a larger crystal is seen in the cavity). The facet to the column is indistinct, but is small in any case.
Remarks. There is no cyrtocrinid which resembles this peculiar form.
-
Family Sclerocrinidae Jaekel, 1918
-
Cyrtocrinus Jaekel, 1891
-
Cyrtocrinus praenutans n. sp., Figs. 14, 15, 16d–e, 17–21, 24–25
1882 Eugeniacrinus nutans Goldfuss; de Loriol, p. 106, pl. 12, figs. 17–23 (cups, columnals).
1928 Eugeniacrinus voultensis Lissajous 1919, proposed by Sayn & Roman, p. 141, for large verrucose or granular cups with radials of equal size.
2007 Cyrtocrinus nutans (Goldfuss); Charbonnier et al., fig. 9d–h, (brachial, cups).
2007 Cyrtocrinus nutans var. voultensis; Charbonnier et al., fig. 9i (verrucose cup).
2007 Gammarocrinites compressus (Goldfuss); Charbonnier et al., fig. 9j (cup).
Material collected by the author from the four localities (not included in statistical analysis): 347 cups, 26 cups with pits, 28 cups with topmost columnal attached, 69 topmost columnals, 357 columnals, 13 columnals with pits, 37 attachment discs, 1 first primibrachial, 41 s primibrachials and 46 secundibrachials.
Material from La Pouza sampling (A. S. Gale, for details see Tables 2–4; Appendix 1, 2): 2,443 cups and radials (calculated as cups), 1,814 top columnals, 7,990 columnals, 1,069 attachment discs, 4,165 first primibrachials, 11,921 s (axillary) primibrachials and 58,744 secundibrachials.
Holotype. Cup, Fig. 14a, M10845.
Paratypes. Cup, Fig. 14b, M10828; secundibrachials Fig. 16d, M10990 and Fig. 17a, M10846.
Etymology. Precursor to nutans.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza near La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Cup low, smooth, rarely verrucose, circular and turban-like in most specimens, rarely somewhat higher and pentagonal with convex radials separated by furrows; cup nearly symmetric in most cases, facet to columnal not much displaced and angle between cup and column not more than approximately 20°. First and second primbrachials articulated by synostosis, exceptionally fused; first primibrachials may have lateral extension, second primibrachials not uncommonly with one or two adoral extensions, exceptionally united adorally. First pinnule on first secundibrachial. Secundibrachials never bipinnulate, the large majority with two muscular facets, rarely one facet synostosial and, exceptionally, two synostosial facets. Surface of brachials mostly smooth, but may be slightly to strongly verrucose; ornamentation increases from first to second primibrachials to secundibrachials, distal brachials more verrucose than proximal ones.
Description. Deepened analyses of some aspects are contained in the sections Ecological interactions of Cyrtocrinus praenutans n. sp., Reconstruction of Cyrtocrinus praenutans n.
sp., and Classification of
Cyrtocrinus praenutans n. sp. as influenced by ontogeny and variability.
Cups are low, circular to rounded pentagonal and rather symmetric in most specimens, with somewhat convex radials. Some large specimens are higher (Fig. 14b). Juvenile cups commonly have a pentagonal profile with notches between the radials (Fig. 14c–e). The surface is smooth and only exceptionally more or less verrucose or granular (Fig. 14k). The radials are joined by synostoses whose surfaces are ornamented by a pattern of dense crenulae (zygosynostosis) (Fig. 14f, g). The lower, proximal side of most cups is a wide and moderately deep bowl for reception of the topmost columnal. The distal, upper side has a mostly rather wide radial cavity sloping to the base of the cavity (Fig. 14f). The cavity may be sculptured into elevated interradial segments (Fig. 14a3, i, j), but in other specimens, such sculpturing is not developed (Fig. 14e, f). Radial articular facets are wide and extend to near the edge of the radials. The aboral ligament fossa is wide and shallow; the ligament pit oval and deep, and it may be small (Fig. 14a2) or wide (Fig. 14k). The transverse ridge is narrow, with a small axial canal (Fig. 14a2, k). The paired muscle fossae are circular and deep, with some structure and they are separated by a notch.
Topmost columnals vary greatly in shape, diameter and height (Fig. 19). Some specimens are preserved with a columnal still attached to the cup (Fig. 19k, m), and in such cases a small topmost columnal may be hidden in the aboral cavity of the cup. In a similar case, the topmost columnal is seen from the outside as a triangular, wedge-shaped element (Fig. 19l). Many specimens have topmost columnals contained in the cavity of the cup; they are low, nearly flat pyramids or cones seen from below (Figs. 18b, c, 19a, c1, n1) and they are articulated to the cup by irregular crenulae or ridges on the upper side (Fig. 19c2). However, the upper facet may also be flat (Fig. 19n2). A number of columnals is more or less oval; heights differ (Fig. 19e, g–i), and the decision as to which side is proximal must be based on the presence of irregular crenulae on the upper side and regular, stronger crenulae on the lower facet, articulated to the column. However, such decision is not possible with a columnal such as in Fig. 19i. Finally, a number of rather high, presumed top columnals have facets that are different at both ends and at an angle to each other (Fig. 19d, j). Again, the facet with regular, radiating crenulae at the cylindrical end is considered to be the lower.
Attachment discs or holdfasts (Fig. 20). The majority of holdfasts are cone-shaped discs, with a concave to flat lower side. Some discs are root-like and probably anchored in soft sediment (Fig. 20g). Exceptionally, discs are attached to a foreign object such as a small oyster (Fig. 20e). Facets to the column vary in diameter and are deeply concave, with a strong rim that may show crenulae.
Columnals (Fig. 21). Pluricolumnals are exceptional in the material and consist of only two ossicles (Fig. 21b). There is great variation in size, height, diameter, shape and articular facet. Columnals have smooth latera and are mostly more or less cylindrical, but may also be slightly convex or concave. In a given columnal, the width of lumen may be narrow at one end and wide at the other, with corresponding differences in crenulation (Fig. 21f). Given the commonly wide lumen of the attachment discs, it is assumed that a narrow lumen is on the proximal facet. Low, cylindrical or lens-like columnals seem to be proximal ones (Fig. 21e, l), and higher columnals may be distal. High, thin columnals (Fig. 21j, m) may be juvenile. Given all the shapes, it is surprising that the reconstructed animal should have only four columnals (see Table 4). Some small columnals are branched (see Appendix 2). They either branch symmetrically, V-like (Fig. 23b) or a branch originates from the side (Fig. 23c). The facets of these columnals do not differ from facets of other small columnals. The riddle of axillary columns in Cyclocrinus, millericrinids and cyrtocrinids has been discussed by Hess (2008, p. 475) and the present material adds still another example.
First primibrachials (Figs. 15i–l, 24i–o). These ossicles articulate to the cup, their proximal facet matching the facet of the cup. Typically, first primibrachials have proximal facets with pronounced muscle fossae (Fig. 15k, l1) and are relatively thin, with a pronounced adoral furrow. Their outline is mostly trapezoidal, but one side may be extended (Fig. 15i). The distal facet is synostosial (Figs. 15l2, 24i–k, m–o), rarely cryptosyzygial (Fig. 24l) and crescent shaped. In some cases, first primibrachials are fused with second primibrachials. Such a fused pair may vary from high (Fig. 15j) to lower (Fig. 25g) to low (Fig. 18d–e); one fused pair has a low proximal (=first primibrachial) part (Fig. 15f).
Second primibrachials (Figs. 15a–h, 24a–h, 25). These distinctive ossicles with a proximal synostosial facet and two distal muscular facets occur in a variety of shapes. The majority are low to high trapezoidal in outline (Figs. 15g, 24a–h, 25e–f). More remarkable are sturdy ossicles with unilateral or paired adoral extensions of variable shape and thickness, and adoral furrows are mostly deep (Figs. 15a–e, 18f). Exceptionally, the processes are completely fused, leaving only a narrow passage for the food groove (Fig. 15h). The figured ossicle resembles second primibrachials of the Oxfordian Pilocrinus moussoni (Desor) (see Hess & Messing 2011, fig. 92g–h).
Secundibrachials (Figs. 16d–e, 17, 18g). Secundibrachials are by far the most common fossils in the La Pouza samples, and they occur in a large variety of sizes and shapes. Because no axillary secundibrachial with a proximal muscular facet has been found, the arms were unbranched after the axillary second primibrachial, and the animal had only ten arms. Proximal brachials are more or less rectangular and massive (Fig. 17a, b, d). They bear only one pinnule socket, situated on the thickened part. This socket is supplied with a branch of the axial food groove (Figs. 16d, 17a, f, h). A first secundibrachial still attached to the second primibrachial has a deep pinnule socket near the distal margin (Fig. 16e). The following pinnule sockets are on the lateral margin, as in the extant Neogymnocrinus richeri (Fig. 16c). No pinnulars were isolated from the washings, but it may be assumed that they were similar to the extant example. A number of secundibrachials have one side extended club-like (Fig. 17e, pinnule socket is on low part at right). The interbrachial facets have small, distinct muscle fossae below a notch for the food groove; the muscle fossae are separated by the axial canal and the transverse ridge from the narrow aboral ligament fossa with its pit. Most of the proximal secundibrachials are smooth, but distal ossicles are increasingly verrucose (Fig. 17c, g). Among the material is a certain percentage of small, thin brachials with the food groove displaced to one side (Fig. 17k). Muscle fossae are small and rather indistinct. It is assumed that such ossicles are from distal parts of the arm. An even smaller percentage of secundibrachials have one or both facets synostosial (Fig. 17i, j) (see Appendix 1). Brachials with synostoses on both facets are thin and lack a pinnule socket. Their position in the arm is unclear. Secundibrachials with synostosial facets do not normally occur in cyrtocrinids where facets are muscular, although synostosial facets of a cyrtocrinid species from the lower Jurassic have been reported by Hess (2006, pl. 6, fig. 16–17).
Remarks. This species dominates the La Pouza fauna, but also occurs in the Bajocian/Bathonian of Pont des Étoiles, the Bathonian of La Clapouze and the Lower Callovien of the Chénier Ravine. It was previously assigned to the Middle Oxfordian C. nutans. In fact, some cups closely resemble those from the Oxfordian. However, the large amount of material now available from La Pouza demonstrates that there are significant differences between the two species separated by a wide stratigraphical gap. Cyrtocrinus nutans was extensively described by Quenstedt (1876) who figured a large number of elements; unfortunately, his figures are so small that details cannot be recognized in many cases. Quenstedt figured attachment discs, each with wide lumen (1876, pl. 105, figs. 144–155), a feature comparable to the discs of C. praenutans that are, however, mostly cone- or dish-like and only rarely root-like. Branched columnals are also recognized in both species, as are columnals of variable shape and length. The cups of C. nutans are commonly more oblique and the radial articular facets may be at a right angle to the column axis. In such cases, the cup may be fused with the top columnal. Such extreme features are unknown from C. praenutans where cup variability is much less. One might say that C. praenutans has a lower degree of crookedness. Of special relevance to the establishment of a new species for the Ardèche material are descriptions of bipinnulate secundibrachials in C. nutans (Quenstedt 1876, pl. 106, figs. 62, 63; p. 434–435). The rectangular aboral profile of the brachials on a curled arm (Fig. 16b) also supports the bipinnulate condition of the Oxfordian species. Well-preserved material from the Middle Oxfordian Birmenstorf Member of northern Switzerland shows this in the necessary detail (Fig. 16a). Incidentally, de Loriol (1889, p. 560; pl. 229, figs. 10–11) described bipinnulate secundibrachials from the Oxfordian of Le Pontet near Saint-Claude (Jura), and thought that they belonged to his Gymnocrinus moeschi (=adorally enclosed second primibrachials of Pilocrinus moussoni [Desor]) (see Hess & Messing 2011, p. 189). Cyrtocrinus nutans also occurs at Saint-Claude. The arms of C. praenutans n. sp. may have resembled those of the living Neogymnocrinus richeri (Bourseau,
Améziane-Cominardi, Avocat & Roux
1991) (Fig. 16c), more or less rectangular brachials proximally, and cuneate brachials distally. Cups of the present species from the Lower Callovian of the Chénier Ravine have been figured by Charbonnier et al. (2007), in part under different names. This is discussed in a following section.
-
Superfamily Plicatocrinoidea Zittel, 1879
-
Family Tetracrinidae Nicosia, 1991
-
Praetetracrinus Jäger, 1995
-
Praetetracrinus
bathonicus n. sp., Fig. 22
Material. Basal elements: 24 (one fived sided, 23 four sided); 56 radials (37 intact, 18 partly broken), 3 columnals.
Holotype. Radial, largest width 3 mm, height 2.5 mm, M19875, Fig. 22a.
Paratype. Tetramerous basal element, diameter 2.5 mm, M10877, Fig. 22h.
Etymology. After the stratigraphic occurrence.
Type locality and horizon. Early Bathonian (Zigzag Zone), La Pouza, La Voulte-sur-Rhône (Ardèche, France).
Diagnosis. Basal element tetramerous, exceptionally pentamerous, lower side slightly concave with radial crenulae mostly in groups, upper side with moderately deep cavity and small facets to radials at the angles with paired axial canals. Radials thin walled, commonly high, with smooth, slightly keeled aboral side, rarely lower and granular aborally; base narrow, facet for primibrachial wide, leading to conical shape of cup with wide radial cavity; radial articular facet crescent shaped, raised into short process at each end, aboral ligament fossa with oval pit, transverse ridge distinct, muscle fossae wide and extending onto the adoral side with lower rim. Columnals circular and facets with four crenulae (corresponding to tetramerous symmetry).
Description. The basal elements are mostly tetramerous, with only one pentamerous specimen. Height is roughly equal to diameter. The facet to the column is circular and concave, with mostly four groups of two to three distinct crenulae. The upper facet is quadratic or pentagonal in outline (depending on the symmetry) and the rim is widened at the corners where paired nerve canals are visible. Radials vary in shape and height. Most are high, thin and aborally smooth, but some are nearly triangular with granular aboral surface (Fig. 22d, e). Most radials are slightly keeled aborally. The radial articular facets have wide, oval muscle fossae with adoral rim and separated by rimmed notch on the inner, adoral side. The muscle fossae are separated by a distinct transverse ridge from the small aboral part with an oval ligament fossa. A radial with apparently two pairs of muscle fossae is shown in Fig. 22b.
Remarks. The elements in question belong to the Plicatocrinoidea Zittel. This superfamily includes two families with a distinct element of fused basals and a variable number of commonly high radials, Plicatocrinidae Zittel and Tetracrinidae Nicosia. The present elements are assigned to the genus Praetetracrinus based on the tetramerous symmetry of the stout basal element. Praetetracrinus
bathonicus n. sp. resembles the Early Jurassic P.
inornatus (Simms
1989) but has thinner and higher radials; in addition, the basal element is higher and angular. From the Toarcian/Aalenian of Germany, Jäger (1995, pl. 6, figs. 9–12) figured several elements with characters closely resembling those of P. bathonicus: a slender, high radial (loc. cit., fig. 12), a columnal (loc. cit. fig. 9), and two basal elements (loc. cit. figs. 10–11). Jäger classified the ossicles as either P. kutscheri Jäger or P. inornatus (Simms). The radials of the Toarcian/Aalenian P. doreckae Jäger (1995) have straight to sligthly concave upper edges and are not keeled aborally. The basal circlet of the Pliensbachian Plicatocrinus sulzkirchenensis Jäger (1993) is penta- to heptamerous with high and narrow radials. In comparison with the Pliensbachian-Toarcian Quenstedticrinus deslongchampsi (de Loriol) (de Loriol 1882, pl. 10; Hess 2006, pl. 6, fig. 1), P. bathonicus n. sp. has thinner and adorally unsculptured radials. Quenstedticrinus Klikushin belongs to a separate family, Quenstedticrinidae Klikushin, 1987, characterized by a cryptic basal circlet within the radial circlet. Plicatocrinus hexagonus Münster from the Middle Oxfordian sponge facies of Germany and Switzerland is mostly hexamerous with a thin, shallow basal element; but the similarly keeled and thin radials resemble those of the present species. Unfortunately, no brachials or pinnulars can be assigned to P. bathonicus n. sp. with certainty, preventing further elaboration of relationships. In contrast to Tetracrinus, the radials of Praetetracrinus and Sacariacrinus are high, resembling those of Plicatocrinus. Jäger (1995), not considering Nicosia’s (1991) establishment of the family Tetracrinidae, placed both Tetracrinus and Praetetracrinus in the family Plicatocrinidae. Thus, Jurassic Plicatocrinoidea appear to constitute a heterogeneous, presumably paraphyletic group, with P. bathonicus n. sp. more closely related to Early Jurassic than to Late Jurassic forms.
-
Suborder Holopodina Arendt, 1974
-
Family Eudesicrinidae Bather, 1899
-
Dolichocrinus
de Loriol, 1891
-
Dolichocrinus aberrans (de Loriol
1882), Fig. 23a
1882 Eugeniacrinus aberrans
de Loriol, p. 148, pl. 15, figs. 4–5
1891 Dolichocrinus aberrans (de Loriol); de Loriol, p. 131; pl. 24, figs. 3–4
1891 Tetanocrinus
aberrans (de Loriol); Jaekel, 1891, p. 628, fig. 15
2007 Dolichocrinus aberrans (de Loriol); Charbonnier et al., fig. 10a
2011 Dolichocrinus aberrans (de Loriol); Hess & Messing, 2011, fig. 101, 3
Material. The author collected eight cups from La Pouza and one cup from Chénier Ravine. The La Pouza sampling (A. S. Gale) furnished 22 cups, all of them more or less broken. Seventeen remains have radial facets preserved, 4 are only parts of the columnal element, and 1 shows facets to basals (see Hess & Messing 2011, fig. 101, 3b). The best preserved cup is 10 mm high, with a radial circlet diameter of 4 mm at the top and a diameter of the column part of 2.3 mm. The largest cup with only a short preserved column part has a diameter of 4.3 mm at the top; the smallest cup has a diameter of 2 mm (column part diameter 1 mm).
Description. The disarticulated or partly broken specimens reveal a wide axial canal between the prolonged, column-like radials (Fig. 23a). Except for size, variability is low between the specimens; radial articular facets are perpendicular to the axis or at only low angle to the column-like part. In the material from the La Pouza claystone beds, no specimen with an occluded radial has been found (Hess & Messing 2011, fig. 101, 3c; collected at La Pouza) and such morphology seems exceptional.
Remarks. The material isolated from the La Pouza claystone beds includes two single radials, nine radial pairs and three radial triplets (see also de Loriol 1882, pl. 15, fig. 6), as opposed to nine articulated specimens (8 with radial articular facets, 1 column part with facets to 5 basals). Such preservation is similar to that of Cyrtocrinus
praenutans n. sp. where isolated radials or disarticulated parts of the cup are also common.
-
Incerti ordinis
-
Family Cyclocrinidae Sieverts-Doreck, 1953
-
Cyclocrinus
d’Orbigny
1850
-
Cyclocrinus rugosus
d’Orbigny
1850, Fig. 23d
1871 Millericrinus; Dumortier, p. 46, pl. 5, figs. 7–11.
1886 Cyclocrinus macrocephalus (Quenstedt); de Loriol, p. 18, pl. 126, figs. 4–9.
2008 Cyclocrinus rugosus
d’Orbigny; Hess, p. 465, text-figs. 1, 2; pl. 1, 2.
Material. Pont des Étoiles: 4 columnals; La Pouza; 34 columnals and 1 pluricolumnal of 2 columnals; Chénier Ravine: 4 columnals; La Clapouze: 3 columnals.
Description. The columnals are cylindrical, with smooth latera and are relatively high; the largest columnal from La Pouza has a diameter of 11 mm and a height of 6 mm; the smallest from this locality has a diameter of 2 mm with similar height. The facets are characteristic of the species. The facet in Fig. 23d1 is representative of the Ardèche material. It has rows of small tubercles radiating from the lumen; in between are larger tubercles and short crenulae or irregular tubercles along the margin.
Remarks. Dumortier (1871, pl. 5, fig. 7–11) figured a small columnal from La Pouza, a larger pluricolumnal of three and a large single columnal with a diameter of 18 mm. The facet of the small columnal (Dumortier 1871, fig. 8) has radial crenulae and tubercles; the facet of the large columnal (Fig. 11) has more or less radial and irregular, vermicose crenulae that extend from the lumen to near the margin. Such differences in ornamentation are common in this species, even in columnals from the same locality (Hess 2008).
