The Echinoid Directory

• Test cordate with shallow frontal sulcus from apex to peristome. Depressed in profile with rounded ambitus.
• Apical disc ethmophract, the madreporite separating the posterior genital plates but not the posterior oculars. With 4 gonopores; subcentral.
• Anterior ambulacrum narrow and sunken adapically. Pore-pairs uniserial and enlarged adapically.
• Other ambulacra petaloid; petals long, parallel-sided and sunken. Anterior petals widely divergent, about same length as posterior petals; no occluded plates at ends of petals.
• Periproct on posterior face; oral side framed by plates 5a/b.
• Peristome D-shaped; facing downwards.
• Labral plate squat and extending to second ambulacral plate. Sternal plates large and symmetrical; episternal plates biserially offset.
• Interambulacra 1 and 4 amphiplacous.
• No primary tubercles differentiated.
• Peripetalous fasciole present. Independent marginal fasciole also present.

Upper Cretaceous (Cenomanian, Turonian) of Portugal.

Mundaster tentugalensis Soares & Devries, 1967, p. 16, 82, by original designation.

• Only the type species.

Spatangoida, Paleopneustina, stem group plesion.

Monotypic.Subjective junior synonym of Polydesmaster.

Differs from all other Paleopnuestina except Periaster in having an ethmophract apical disc. Periaster is distinguished because its marginal fasciole crosses plate 5 (not plate 4 as in Mundaster) in interambulacra 1b and 4a, and lateroanal and peripetalous branches coalesce on that plate to give rise to a single anterior fasciole.

The taxon has been described and reillustrated by Markov & Solovjev (2001).

Markov, A. V. & Solovjev, A. N. 2001. Echinoids of the family Paleopneustidae (Echinoidea, Spatangoida): morphology, taxonomy, phylogeny. Geos 2001, 1-109.