The Echinoid Directory

• Test small and globular in outline and profile; no anterior sulcus.
• Apical disc ethmophract with four gonopores; central.
• Anterior ambulacrum weakly sunken adapically; pore-pairs enlarged and presumably associated with funnel-building tube-feet. Sulcus fades towards ambitus and disappears.
• Paired ambulacra subpetaloid; petals cruciform, with anterior pair longer than posterior pair. Petals straight, weakly depressed and with narrow, smooth interporal zone. Pore-pairs small with both pores rounded.
• Peristome small, D-shaped, with strong lip.
• Labral plate flask-shaped, widening to posterior and extending to third ambulacral plate. Sternal plates asymmetric with oblique midline suture; episternal plates and subsequent plating biserial.
• Periproct small and circular, near top of posterior face.
• Peripetalous fasciole present; not indented interradially.
• Aboral tuberculation fine and uniform.

Upper Cretaceous; Europe.

Peroniaster cotteaui Gauthier, 1887, p. 246, by original designation.

• P. cottteaui Gauthier, 1887; Campanian, France.
• P. nasutulus Sorignet, 1850; Turonian, western Europe.

Spatangoida, Hemiasterina, Hemiasteridae.

Subjective junior synonym of Hemiaster.

Lambert & Thiery (1924, p. 507) included just two species in this genus. One of these, Hemiaster nasutulus, has been recently redescribed. The genus is not based on juveniles, as Mortensen (1950) suspected, since the species occurs in large numbers and never reaches more than about 20 mm in length. Gonopores are already present by 10 mm.

Peroniaster resembles Bolbaster in shape and in its rudimentary petal development. However, it differs from that genus and more closely resembles Hemiaster in having the labral plate extending to ambulacral plate 3 and its sternal plates asymmetrical.

Gauthier, A. 1887. Description des especes de la Craie de Reims et de quelques especes nouvelles de l'Aube et de l'Yonne. Bulletin de la Societe des Sciences de l'Yonne 41, 367-399, pls 4-8.

Smith, A.B., Paul, C.R.C., Gale, A.S. & Donovan, S. K. 1988. Cenomanian and Lower Turonian echinoderms from Wilmington, south-east Devon, England. Bulletin of the British Museum (Natural History) Geology Series 42, 1-245.