The Echinoid Directory

• Test ovate with deep anterior sulcus; slightly pointed to rear and carinate.
• Apical disc ethmolytic, with two large posterior gonopores and two smaller anterior gonopores.
• Anterior ambulacrum deeply sunken adapically, becoming less pronounced towards the ambitus; pore-pairs in single column series, specialized for funnel-building tube-feet.
• Other ambulacra also deeply sunken, anterior petals much longer and more flexed than posterior petals.
• Periproct small and marginal, on near-vertical truncate face.
• Peristome weakly labiate; wider than long.
• Labral plate short and wide; in broad contact with sternal plates; not reaching start of ambulacral plate 2 at rear.
• Plastron wide and ovate, episternal plates not paired and opposite and not forming significant part of plastronal area.
• Aboral tuberculation fine, uniform and dense.
• Well-developed peripetalous and latero-anal fascioles.

Miocene, circum-Mediterranean.

Schizaster eurynotus Sismonda, 1842, p. 20. Specimen (not topotype material) illustrated in Sismonda 1844, pl. 2, figs 2, 3.

• Lambert & Thiery (1924, p. 527) included a large number of species in this genus.

Spatangoida, Paleopneustina, Schizasteridae

Subjective junior synonym of Schizaster Agassiz, 1836

Since the type species of Agassiz\'s Schizaster has four, not two gonopores, with the anterior genital plates perforated by small gonopores, there is no substantial difference between it and Aplospatangus. Brachybrissus Pomel, 1883 has an unknown number of gonopores and may eventually prove to be a senior subjective synonym of this genus.

Lambert, J. 1907. Description des echinides fossiles de la province de Barcelone. Part 2. Memoires de la Societe geologique de France, Paleontologie 14∫, 59-128, 5 pls. [for 1906]

Sismonda, E. 1842. Monografia degli Echinidi fossili del Piedmonte. Memorie della Reale Accademia della Scienze di Torino Serie Seconda IV, 1-53.

Sismonda, E. 1844. Memoria geo-zoologica sugli echinidi fossili del Contado di Nizza. Memorie della Reale Accademia della Scienze di Torino Serie Seconda VI, p. 371, pl. 2, figs 2, 3.