Cherbonniericrinus requiensis, Roux & Martinez & Vizcaïno, 2021

Roux, Michel, Martinez, Alain & Vizcaïno, Daniel, 2021, A diverse crinoid fauna (Echinodermata, Crinoidea) from the Lower Eocene of the Gulf of Languedoc (Corbières, Aude, southern France), Zootaxa 4963 (2), pp. 201-242 : 230-232

Cherbonniericrinus requiensis n. sp.

Fig. 16A–G

Type material. 5 aboral cups, the best-preserved of which is designated holotype ( MNHN.F. A82013 ) ( Fig. 16E–G ), the others are paratypes 1 to 4 .

Etymology. From the type locality Réqui near Montlaur (Val de Dagne, Aude).

Type stratum. Base of the blue marls of the middle Ilerdian, above the Solenomeris limestones, late NP10, but maybe already NP11.

Type locality. Réqui near Montlaur (Val de Dagne, Aude) .

Diagnosis. Small species; aboral cup an inverted truncated cone in shape, external surface slightly concave to convex; sutures between plates variable, weakly marked between basals; aboral end diameter equal to or slightly less than 0.5 Dc; adoral face of radial circlet with discrete interradial crests, muscular synarthries as wide as radials, broad central cavity.

Description of type series ( Fig. 16 ). Quantitative characters of aboral cups of type series given in Table 16. Holotype ( Fig. 16E–G ) with aboral cup almost twice as high as wide, slightly swollen in upper half of basal circlet, lower part of basal circlet moderately inverted conical, slight constriction at basal-radial transition, basals about three times higher than radials, sutures between basals discrete or inconspicuous, marked sutures between basal and radial circlets and between radials. Aboral end diameter half of the maximum diameter of cup (Dp’/Dc 0.49). Adoral face of radial circlet with slight marginal interradial tips but without conspicuous interradial ridges, muscular synarthries with reduced aboral ligament fossa and well-developed muscular fossae with lateral edges erected ( Fig. 16G ), broad central cavity (Dd/Dc 0.49); pattern similar to that of extant specimen ( Fig. 16H ). Paratypes with aboral cup of variable flare and height, lateral profile slightly convex ( Fig. 16A ) to markedly concave ( Fig. 16D ); sutures between basals conspicuous ( Fig. 16A ) to absent ( Fig. 16B ); distal face of radial circlet imperfectly preserved in largest paratype ( Fig. 16C ).

Remarks. The aboral cup of the holotype of C. requiensis ( Fig. 16E–G ) is the closest to those of the extant species C. cherbonnieri (Roux, 1976) ( Fig. 16H ), both lacking sutures between basals. The paratypes ( Fig. 16A–D ) have an aboral cup general shape that is similar to those from the Danian of Denmark, attributed to? Cherbionniericrinus sp. ( Roux et al. 2019), which differ, however, by a larger adoral cavity like in the extant species. Columnals are unknown. The extant species C. cherbonnieri is anchored to the substratum by rhizoids penetrating into the sediment ( Roux 1977).

Occurrence. Early Ypresian (middle Ilerdian) of Corbières; species known only from Réqui near Montlaur (Val de Dagne, Aude).

Figures

FIGURE 16. Aboral cups of type series of Cherbonniericrinus requiensis n. sp. A–D: paratypes (MNHN.F.A82014); E–G: holotype (MNHN.F.A82013), G: detail of muscular synarthry of distal face; H: aboral cup of C. cherbonnieri, Recent, Bay of Biscay, (MNHN.IE.2016.748). Scale bar equals 0.5 mm (A–F, H) and 0.25 mm (G).