The Echinoid Directory

Plesiopatagus Pomel, 1883, p. 32

[=Plesiospatangus Cotteau, 1886, p.129 (nom. van.) ]

Diagnostic Features	Test ovate with shallow but distinct anterior sulcus; posterior face truncate. Test flattened in profile. Apical disc ethmolytic with two gonopores (no gonopores on right-hand genital plates); a little anterior of centre. Anterior ambulacrum sunken from apex to peristome; narrow; pore-pairs small and rudimentary. Paired ambulacra petaloid aborally; sunken; weakly bowed and closing distally. Anterior and posterior petals similar in length, the anterior quite widely divergent. No reduction of pore-pairs in anterior column of anterior petals adapically. Peristome D-shaped and slightly inclined towards anterior. Labral plate elongate; extending to third ambulacral plate. Sternal plates large and triangular. Episternal plates not much tapering posteriorly. Periproct on posterior truncate face; just visible in aboral view. Subanal fasciole present; bilobed. Peripetalous fasciole present; not indented behind anterior petals. Larger tubercles developed inside peripetalous fasciole; tubercles crenulate but not sunken.
Distribution	Eocene, Egypt and Middle East.
Name gender	masculine
Type	Eupatagus cotteaui de Loriol, 1880, p. 611, by original designation.
Species Included	P. cotteaui (de Loriol, 1880); Thebes Formation, Lower Eocene, Egypt.
Classification and/or Status	Spatangoida, Micrasterina, unnamed family.
Remarks	Differs from all other Micrasterina in having two gonopores, the two right-hand genital plates having no openings. Otherwise close to Brissopatagus in appearance. Pomel, A. 1883. Classification méthodique et genera des Échinides vivante et fossiles. Thèses présentées a la Faculté des Sciences de Paris pour obtenir le Grade de Docteur ès Sciences Naturelles, 503, 131 pp. Aldolphe Jourdan, Alger. Roman, J. & Struogo, A. 1994. Echinoides du Libyen (Eocene inferieur) d\'Egypt. Revue de paleobiologie 13, 29-57.