A diverse crinoid fauna (Echinodermata, Crinoidea) from the Lower Eocene of the Gulf of Languedoc (Corbières, Aude, southern France)
Author
Roux, Michel
Muséum national d’Histoire naturelle, UMR 7205 ISYEB MNHN-CNRS-UPMC-EPHE, Département Systématique et Évolution, CP 51, 57 rue Cuvier, 75231 Paris Cedex 05, France
Author
Martinez, Alain
Chemin de Saint Estève, 11200 Lézignan-Corbières. France
Author
Vizcaïno, Daniel
7 rue J. - B. Chardin Maquens, 11000 Carcassonne, France
text
Zootaxa
2021
2021-04-19
4963
2
201
242
journal article
7139
10.11646/zootaxa.4963.2.1
049b6936-13d8-42d6-9468-2019ddf78d14
1175-5326
4700704
ACEC045B-AEE7-43FB-A074-D2AD6CB40F1D
Genus
Pseudoconocrinus
Roux, Eléaume and Améziane, 2019
Type
species.
Conocrinus doncieuxi
Roux, 1978a
,
lower Ypresian
.
Emended diagnosis.
Aboral cup shape highly variable but never inverted conical, except in some juveniles; sutures between aboral cup ossicles often conspicuous. Distal face of radial circlet with small central depression (ratio to radial circlet diameter 0.20–0.30), long conspicuous interradial crests separating large subtrapezoidal muscular synarthries, arm sockets about as wide as radials, muscular areas moderately concave with inner side slightly erect or not at all. Arms divided at IBr2ax, synostosial symmorphy at IBr1+2 without trifascial pattern, IBr1 short and substantially wider than high, IBr2ax regularly pentagonal, occasionally two kinds of axillaries found in association with aboral cups: a large one which is wider than tall, and a smaller one which is substantially taller than wide, suggesting change during growth ontogeny or possible additional branching, free arms with frequent brachial pairs (two IIBr united by flat synostosis). Occasionally proxistele well differentiated with thick discoidal columnals, progressive transition from mesistele to dististele with numerous columnals bearing thin rhizoids.
Remarks.
Pseudoconocrinus
differs mainly from other Eocene and Recent rhizocrinid genera in having arms dividing at IBr2ax.
Stratigraphical distribution.
Danian–Ypresian.