The Echinoid Directory

Paronaster Airaghi, 1906, p. 107

Diagnostic Features	Test large, cordiform in outline and peaked in profile. Lower surface rather flat (only known specimen appears somewhat crushed). Apical disc at apex; poorly preserved. Structure unknown. Broad and distinct frontal groove at the ambitus and continuing to the peristome. Petals well developed; pore-pairs conjugate, with outer pore elongate, but with no strong difference between anterior and posterior columns. Pore-pairs in anterior ambulacrum similar to rest. Plastron weakly keeled - plating unknown. Periproct on short vertical posterior face. Peristome semilunate and associated with a broad and rather shallow frontal groove but without being sunken. Small, scattered tubercles set in a dense groundmass of granules. No fascioles.
Distribution	Late Cretaceous (Scaglia - i.e. Coniacian-Campanian), Italy.
Name gender	masculine
Type	Paronaster cupuliformis Airaghi 1906, p. 108, by original designation.
Species Included	Only the type species.
Classification and/or Status	Spatangoida or Holasteroida; family unknown. Monotypic.
Remarks	Lack of knowledge of plastron plating makes it impossible to place this genus with any certainty. It differs from all other holasteroids in its strongly conical aboral surface and by the subpetaloid nature of the frontal ambulacrum. Possibly a spatangoid, since the apical disc structure is unknown. C. Airaghi 1906. Un nuovo genere della sottofamiglia delle Echinocorynae. Atti della Societa Italiana di Scienze naturali e del Museo Civico di Storia Naturale in Milano 45, 107-110.