The Echinoid Directory

Stirechinus Desor, 1856, p. 131

[= Styrechinus Desor, 1856, p. 131; nomen null.]

Diagnostic Features	Apical disc plating absent from all known specimens of the type species. Ambulacral plates trigeminate; plate compounding in echinid style; pore-pairs forming a near vertical arc. One primary tubercle to each ambulacral plate. Primary interambulacral tubercles linked into vertical columns by pronounced ridges from the ambitus aborally: small secondary tubercles occur on interambulacral plates but leave the interradius largely naked. Sutures deeply incised. Peristome relatively small and with indistinct buccal notches.
Distribution	Upper Miocene to Pleistocene of the Mediterranean, Recent in the Atlantic.
Name gender	masculine
Type	Stirechinus scillae Desor, 1856, p. 131, by monotypy.
Species Included	S. scillae Desor, 1856, Late Miocene to Plio-Pleistocene of France, Sicily and Malta. Echinus tyloides Clark, 1912; Recent, West Atlantic.
Classification and/or Status	Camarodonta; Echinoida; Echinidae.
Remarks	Differs from the closely related Gracilechinus Fell & Pawson, in having more nodulose plate surfaces, with interambulacral tubercles linked by a vertical ridge. Mortensen (1943) thought that the type species (a fossil) was probably either synonymous or very closely related to Echinus tyloides Clark, 1912. As both show a similar pattern of vertical ridges linking tubercles they are here treated as congeneric. Mortensen, T. 1943. A monograph of the Echinoidea Part III, 3. Camarodonta II. C. A. Retzel, Copenhagen.