The Echinoid Directory

Desorella Cotteau, 1855, p. 713

[=Desoria Cotteau, 1855, p. 221 non Nicolet, 1842 ]

Diagnostic Features	Test ovate; depressed to subconical in profile, ambitus rounded and below mid-height; shallow notch at posterior. Apical disc central, tetrabasal with 4 gonopores; elongate with small auxilliary plates incorporated between paired oculars and posterior genital plates. Periproct supra-ambital in shallow anal sulcus, separated from apical disc by numerous interambulacral plates. Periproct tear-drop shaped, pointed adapically. Ambulacra non-petaloid aborally; pore-pairs simple. Ambulacra narrow on oral surface; plating remains simple to peristome with pore-pairs arranged uniserially. No buccal pores. Peristome small, oblique with long axis from interambulacrum 3 to ambulacrum I; sunken with wel-developed well; slightly anterior of centre; interambulacra not swollen around peristome. No buccal notches. tuberculation fine and uniform.
Distribution	Upper Jurassic (Bajocian?, Oxfordian-Kimmeridgian), France, UK.
Name gender	feminine
Type	Hyboclypus elatus Desor, in Agassiz & Desor, 1847, p. 152, by subsequent designation of Cotteau, 1873, p. 333.
Species Included	D. elata (Desor, in Agassiz & Desor, 1847); Bajocian?, Oxfordian-Kimmeridgian, western Europe.
Classification and/or Status	Stem group Irregular; Desorellidae Monotypic.
Remarks	Distinguished from Galeropygus by the widely separated periproct / apical disc and by the complete absence of pore crowding adorally. Often preserved as an internal mould in chert. Barras, C. 2006. British Jurassic irregular echinoids. Monograph of the Palaeontographical Society, 1-168, pls 1-14 (publication number 625). Cotteau, G. 1855. Note sur un nouveau genre d’échinide fossile: Genre Desorella. Bulletin de la Société géologique de France, (2) 12, 710-716.