The Echinoid Directory

Gymnopatagus Doderlein, 1901, p. 22

Diagnostic Features	Test ovate with distinct anterior sulcus; posterior face truncate. Depressed in profile with flat oral surface. Apical disc ethmolytic with four gonopores; central. Gonopores on inner part of genital plates. Anterior ambulacrum depressed - sulcus deepening to the ambitus. Pore-pairs small and uniserially arranged; tube-feet simple. Paired ambulacra petaloid; anterior and posterior pairs subequal in length. Petals bowed and closing distally. Slightly smaller pore-pairs adapically in the anterior column of the anterior petals. Peristome D-shaped and downward-facing; without anterior sulcus. Labral plate elongate; extending to third ambulacral plate. Sternal plates triangular; fully tuberculate. Episternal plates almost as large as the sternal plate. Sternal-episternal plate boundary V-shaped (V pointing posteriorly). Periproct on posterior truncate face. Subanal fasciole present; shield-shaped; three ambulacral plates enter it on either side. Peripetalous fasciole present; not indented behind anterior petals. Aboral tuberculation heterogeneous; large primary tubercles in anterior and lateral paired interambulacra; tubercles crenulate and not sunken.
Distribution	Recent; Indo-West Pacific.
Name gender	masculine
Type	Gymnopatagus valdiviae, Doderlein, 1901, p. 23, by original designation.
Species Included	Gymnopatagus valdiviae Doderlein, 1901; Recent, Indian Ocean. G. magnus Agassiz & Clark, 1907; Indo-West Pacific.
Classification and/or Status	Spatangoida, Micrasterina, Maretiidae. Presumed monophyletic.
Remarks	Differs from Maretia in having a well-marked frontal groove and peripetalous fasciole. Doderlein, L. 1901. Zoologischer Anzeiger 23, p. 22. Doderlein, L. 1906. Die Echinoiden der deutschen Tiefsee-Expedition. Deutsche Tiefsee-Expedition 1898-1899 5, 63-290, pls 9-50.