The Echinoid Directory

Plesiocorys (Plesiocorys) Pomel, 1883, p. 45

Diagnostic Features	Test ovate with flat base, domal upper surface and weak anterior sulcus. Apical disc subcentral with four gonopores. All ambulacra with simple, rounded pore-pairs adapically. Plastron plating uniserial with 2 to 4 post labral plates arranged uniserially. Peristome small and ovate; facing downwards. Periproct on short truncate posterior face. Aboral tuberculation uniform and fine. Marginal fasciole may be present in small individuals of the type species.
Distribution	Upper Cretaceous (Turonian to Santonian).
Name gender	feminine
Type	Holaster placenta Agassiz, in Agassiz & Desor, 1847, p. 27(133), by subsequent designation of Wagner & Durham, 1966, p. U533.
Species Included	P. (P.) transiens Smith & Wright, 2003; Turonian, UK. P. (P.) placenta Agassiz, in Agassiz & Desor, 1847; Coniacian, western Europe. P. (P.) basiprocta Smith & Wright, 2003; Santonian, UK..
Classification and/or Status	Holasteroida, Cardiasteridae. Monophyletic.
Remarks	Differs from Plesiocorys (Sternotaxis) in completely lacking any frontal depression, even in small individuals. Smith, A. B. & Wright, C. W. 2003. British Cretaceous echinoids. Part 7, Atelostomata, 1. Holasteroida. Palaeontographical Society Monographs, London. Pp. 440-568, pls 139-182.