The Echinoid Directory

• Test ovate with narrow and well-defined anterior sulcus with sharp carina.
• Apical disc with four gonopores. Hydropores scattered over all four genital plates and the anterior three ocular plates.
• Paired ambulacra rather strongly flexed and with columns markedly unequal. Pore-pairs in posterior columns conjugate and elongate; those in the anterior column small or rudimentary especially adapically.
• Frontal groove continuous from apex to peristome; mouth largely covered by labral plate in oral view.
• Plastron plating protosternous with labral plate extending to touch second sternal plate. May become uniserial adorally in some individuals/species.
• Paired posterior interambulacra meridoplacous.
• Periproct inframarginal, clearly visible in oral view. Two subanal protuberances.
• Aboral tuberculation fine and homogeneous.
• No fascioles present.

Upper Cretaceous (Campanian-Maastrichtian), Europe, North Africa, Middle East, India.

Spatangus striato-radiatus Leske, 1778, p. 104, by original designation.

• H. striatoradiatus (Leske, 1778); Maastrichtian of western Europe.
• H. delettrei Peron & Gauthier; Late Campanian, Algeria.
• H. pyrenaicus Hebert, 1875; Maastrichtian, Pyrenees, Middle East, North Africa, India.
• H. compressus Noetling, 1897; Maastrichtian, North Africa, Middle East, India.
• H. arabicus Ali, 1989; Maastrichtian, United Arab Emirates.
• H. oculatus Cotteau, 1892; Maastrichtian, Belgium.
• H. persicus Cotteau & Gauthier, 1895; Campanian-Maastrichtian, Iran and Arabian Peninsula.
• H. cotteaui Lambert in Peron, 1887; Campanian, France.

Holasteroida, Hemipneustidae.

Possibly paraphyletic, by exclusion of Toxopatagus.

Differs from Pseudholaster and Cardiaster in its more high-domed profile, in having the periproct opening distinctly inframarginal and in having much more strongly flexed and differentiated anterior and posterior columns of pore-pairs in the paired ambulacra aborally. It further differs in having hydropores scattered over all anterior plates of the apical disc, rather than confined to just plate G2. It differs from the very similar Opisopneustes in having the inframarginal periproct and in lacking larger primary tubercles on adapical interambulacral plates. It has a more rounded profile and less well developed anterior sulcus than Toxopatagus.

Agassiz, L. 1836. Prodrome d'une monographie des Radiaires ou Échinodermes. Mémoires de la Société des Sciences naturelles de Neuchâtel, 1, 168-199.

Smith, A. B. 1995. Late Campanian-Maastrichtian echinoids from the United Arab Emirates-Oman border region. Bulletin of the Natural History Museum London (Geology Series) 51, 121-240.