The Echinoid Directory

Aliaster Valdinucci, 1975, p. 453

Diagnostic Features
  • Test ovate with shallow anterior sulcus; posterior face truncate. Test wedge-shaped in profile.
  • Apical disc ethmolytic with four gonopores; a little posterior of centre.
  • Ambulacrum III in sulcus aborally which shallows close to the ambitus. Pore-pairs with enlarged periporal node; closely spaced and presumably associated with funnel-building tube-feet.
  • Paired ambulacra petaloid; petals long, flexed and sunken. Anterior petals widely diverging; posterior pair about half as long as anterior pair.
  • Peristome a little removed from anterior border; kidney-shaped and largely hidden in oral view by labral plate.
  • Labral plate short and quadrate, not extending beyond first ambulacral plate. Sternal plates large and triangular; symmetric; forming most of oral surface. Episternal plates biserially offset.
  • Periproct towards top of posterior truncate face. Posterior face undercut in type species.
  • Peripetalous fasciole present, indented by two interambulacral plates behind the anterior petals. No other fascioles reported.
Miocene-Pliocene, circum-Mediterranean.
Name gender masculine
Opissaster lovisatoi Cotteau, 1895, p. 48, by original designation.
Species Included
Valdinucci (1975) included the following species:
  • A. lovisatoi (Cotteau, 1895); Upper Miocene (Tortonian), Sardinia
  • A. insignis (Pomel, 1887); Upper Miocene, Morocco
  • A. cotteaui (Wright, 1855); Upper Miocene, Malta, North Africa
  • A. jourdyi (Peron & Gauthier, 1891); Pliocene, Algeria
  • A. almerai (Lambert, 1906); Miocene, Sardinia
  • A. aichinoi (Checchia Rispoli, 1927); Middle Miocene, Lybia.
Classification and/or Status

Spatangoida, Paleopneustina, Schizasteridae.

Subjective junior synonym of Opissaster Pomel, 1883.


Supposedly differs from Opissaster  by its frontal groove which indents the ambitus. However no good test architectural features appear to distinguish Opissaster from Aliaster.

Valdinucci, A. 1975. "Aliaster" nuovo genere di echinide istituito per un piccolo gruppo di specie tratte dai generi Trachyaster ed Opissaster (Famiglia Hemiasteridaea Clark). Bollettino del Servizio Geologico d'Italia 94, 453-488.