Endoxocrinus gastaldii ( Michelotti, 1847 )

Roux, Michel & Philippe, Michel, 2021, Early Miocene stalked crinoids (Echinodermata) from the southern Rhodanian basin (southeastern France). Paleoenvironments and taxonomy, Zootaxa 5052 (3), pp. 301-331 : 315-317

? Endoxocrinus gastaldii ( Michelotti, 1847)

Figs. 3 , 5 (morphotype A), 7, Table 4

Synonymy. Pentacrinus gastaldii Michelotti, 1847: 59 , pl. 16, fig. 2; Pentacrinus gastaldi Locard, 1877: 207–209 ; Pentacrinus miocenicus de Loriol, 1897: 127–129 , figs. 17–18; Pentacrinus gastaldii Manzoni, 1878: 1–2 , fig. 1; Noelli, 1900: 24–28, figs. 1–32 pars; Albus, 1931: 283–285, pl. 10 (fig. 7); Isocrinus gastaldii Sieverts-Doreck, 1933:165 ; Biese and Sieverts- Doreck, 1939: 37–38; Sandor, 1983: 171–173, figs. 1–3; Neocrinus aff. gastaldii Roux and Montenat, 1977: 408–409 , pl. 16 (figs. 1–2); Metacrinus gastaldii Klikushin, 1982: 305 ; 1992: 128 pars; Pentacrinus gastaldii Manni, 2015: 59 , fig. 22 pars.

Material examined. Avignon (2 Plc including 1 infraN, 3 isolated IN), Picabrier (14 Plc, 36 isolated IN, 17 isolated N), Entrechaux Ferme Pie (1 Plc + 1 IN), Entrechaux Pont Saint-Michel (1 IN), Notre-Dame du Château (3 Plc).

Emended diagnosis. Large species with a columnal diameter that can exceed 9 mm, columnals usually strongly star-shaped, tending to be more pentagonal in certain distal nodotaxes; maximum number of successive internodals observed 11; symplexies with open petaloid zones even in large distal nodotaxes, ligamentary areas fusiform and narrow, always at least four times longer than wide, number of crenulae per petaloid zone usually greater than 16 (mode 18), up to 21, median crenulae longer than the others and may form chevrons with those of adjacent petaloid zones in distal columnals, no furrow separating the petaloid zones except in the most proximal columnals; nodal with cirral insertions substantially wider than high and always intersecting the distal facet border, sometimes also proximal one, cryptosymplexies with more marked symmorphy in the interpetaloid zones, presence of fine interpetaloid grooves and marginal crenulations of variable extension; lateral faces of columnals smooth and convex, without ornamentation. Crown unknown.

Description. Columnals markedly star-shaped, side faces convex; symplexies of open ZP with the areola usually narrow up to 7 times longer than wide, Cr/PZ usually from 17 to 19 and reaching 21 in largest Co, inner crenularium poorly differentiated or flat. Proximal Co highly starred ( Fig. 7A, D–E ), symplexy with regularly arranged short Cr leaving free most of IPZ ( Fig. 7D–E ). More distal Co less starry ( Fig. 7B ) rarely subpentagonal ( Fig. 7C ) with Cr of median crenularium entirely covering IPZ and forming chevrons ( Fig. 7B, F ). Ndx with Co of highly variable thickness even distally ( Fig. 7C ); N markedly thicker than IN, especially in young individuals ( Fig. 7G ), this difference decreasing with growth ( Fig. 5 right), distal facet (cryptosymplexy) more or less regularly concave, about 8 small marginal cr per IPZ ( Fig. 7 I ); cirrus socket well-developed at least twice as wide as high and usually intersecting distal facet border ( Fig. 7H–I ), sometimes also on the proximal one ( Fig. 7J ), low fulcral ridge limited by two triangular culminae often moderately developed. At Picabrier (see Table 4 for quantitative characters): symplexies with 18 to 20 Cr/PZ (60%), 14 or 15 for smallest Co; distal nodal facets and symplexial ligament areas often excessively concave because of pyrite oxidation corrosion; cryptosymplexies rarely well preserved, IPZ usually in relief with a more or less marked axial groove, stalk canal inconspicuous probably obstructed by a dense secondary stereom ( Fig. 7I ). In other sites, only a small number of specimens, but often with Plc less fragmented ( Fig. 7A–C ) than in Picabrier. One of them, from Notre-Dame du Château (de Loriol 1897, Fig. 18) is composed of 10 IN without infraN indicating Ndx of at least 11 IN ( Fig. 7A ).

Remarks. Manni (2015: 59, fig. 22) considered the single specimen (Plc of 3 IN) from the Middle Miocene near Turin used by Michelotti (1847) to describe Pentacrinus gastaldii as lost. He proposed that four internodals belonging to the Michelotti’s collection (Paleontological Museum of “Sapienza” in University of Rome) constitute the type series. Three of these internodals are star-shaped and correspond well to the original figure. The fourth rounded pentagonal with wide and closed petaloid zone is different. The type-series must be reduced to three columnals which could have the value of neo-syntypes if accompanied by a precise description. The best preserved specimen of? E. gastaldii is a markedly star-shaped stalk, 150 mm long, with the basal circlet at proximal end, that was described by Manzoni (1878). This remarkable specimen comes from Montese molasse (Middle Miocene) near Modena.

Among the four syntypes of Pentacrinus miocenicus from Notre-Dame du Château, two belong to? E. gastaldii ( Loriol 1897, figs. 17 and 18). Locard (1877) reported one star-shaped pluricolumnal of? E. gastaldii , D 9 mm, from Bonifacio (South Corsica). This specimen, housed in the Péron’s collection (MNHN.S.11062), most probably comes from the Lower Langhian ( André et al. 2011). Cooke (1896) identified? E. gastaldii in the Miocene Globigerine marls of Malta. We have examined several columnals from Malta (MNHN.F.B.33193) belonging to the d’Orbigny’s collection (no. 11215):? E. gastaldii is associated with M. berthei , the two species having morphologies similar to those observed at Picabrier. Since de Loriol (1897) and Noelli (1900), many authors (including Klikushin 1992) have confused the species berthei , gastaldii and miocenicus .

Occurrence in southeastern France. Avignon(Palais des Papes), Caumont-sur-Durance(Picabrier), Entrechaux (Pont Saint-Michel), Entrechaux (Ferme Pie), Saint-Etienne du Grès (Notre-Dame du Château). Late Burdigalian- Early Langhian.

Figures

FIGURE 3. Variation in the general shape and size of isocrinid columnals from Picabrier (Caumont-sur-Durance). D: diameter, H: height, IN: internodal, Nd: nodal. Morphotype A is attributed to?Endoxocrinus gastaldii and morphotype B to Metacrinus berthei (see text). Values in mm, except ratios and number of columnals (Nd and IN).

FIGURE 5. Variation in the general shape and size of isocrinid columnals of the two main isocrinid species from the different sites in the Rhône-Provence Bay. Entr.: Entrechaux, IN: internodals, N: nodals. The envelopes of points corresponding to the sites Picabrier and Avignon (Palais des Papes) are only figured (see Figs. 3 and 4), except for E. gastaldii from Avignon. Values in mm, except for ratios H/D.

FIGURE 7. Columnals and pluricolumùnals of?Endoxocrinus gastaldii. A–B: from Notre-Dame du Château, A: proximal pluricolumnal (cotype of Pentacrinus miocenicus de Loriol, 1897, fig. 18) (MASRP 2020.5012), B: more distal subpentagonal pluricolumnal (MASRP 2020.5022); C–D: from Palais des Papes in Avignon (MHNL 20.062709), C: distal pluricolumnal, D: nodal from proximalmost stalk, proximal symplexial facet; E–J: from Picabrier (MHNL 20.062711), E: internodal from proximal middle stalk, F: internodal from distal middle stalk, G–H: nodal from a young individual, G: oblique proximal view, H: side view showing cirrus sockets, I–J: nodals from large specimens, I: oblique distal view showing the cryptosymplexial facet, J: oblique proximal view showing a cirrus socket. Scale bar equals 1 mm.