The Echinoid Directory

Amoraster McNamara & Ah Yee, 1989, p. 178

Diagnostic Features	Test ovate without anterior sulcus; inflated in profile with weakly keeled sternum. Apical disc ethmolytic with four gonopores; anterior of centre. Gonopores on inner half of genital plates. Anterior ambulacrum narrow and faintly depressed adapically; flush by ambitus; pore-pairs small and undifferentiated. Paired ambulacra petaloid and flush. Petals bowed with wide interporal area. Adapical pore-pairs rudimentary. Petals closed distally; pore-pairs conjugate and rather deeply incised. Peristome D-shaped and downward-facing. Phyllodes well-developed with about 6 enlarged tube-feet in lateral ambulacra. Labral plate elongate - extended to second ambulacral plate. Episternal plates paired and forming rear part of plastron; strongly contracted posteriorly. Periproct on posterior slightly undercut face. Subanal fasciole present; shield-shaped; enclosing about 5 pore-pairs on each side. Peripetalous fasciole present; narrow; not indented behind anterior petals, but indented in anterior interambulacra; bounding outer end of petals. Aboral tuberculation rather fine and uniform - no primary tubercles in type species [in second species assigned there are primary tubercles in posterior series of paired interambulacra].
Distribution	Miocene, Australia.
Name gender	masculine
Type	Amoraster paucituberculata McNamara & Ah Yee, 1989, p. 179, by original designation. Holotype Western Australia Museum, Perth, Australia WAM 87.303.
Species Included	A. paucituberculata McNamara & Ah Yee, 1989; Middle to Late Miocene, Australia A. tuberculata McNamara & Ah Yee, 1989; Lower Miocene, Australia
Classification and/or Status	Spatangoida, Micrasterina, Maretiidae. Subjective junior synonym of Granobrissoides Lambert, 1920.
Remarks	McNamara & Ah Yee (1989) distinguished this genus from Granobrissoides by "its larger size, anterior apex, more parallel-sided, sunken petals, wider periproct and broader bifastigate plastron, which unlike Granobrissoides is not parallel-sided". These differences seem minor and the two genera are synonymised here. McNamara, K. J. & Ah Yee, C. 1989. A new genus of brissid echinoid from the Miocene of Australia. Geological Magazine 126: 177-186.