The Echinoid Directory

• 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.

Upper Miocene to Pleistocene of the Mediterranean, Recent in the Atlantic.

Stirechinus scillae Desor, 1856, p. 131, by monotypy.

• S. scillae Desor, 1856, Late Miocene to Plio-Pleistocene of France, Sicily and Malta.
• Echinus tyloides Clark, 1912; Recent, West Atlantic.

Camarodonta; Echinoida; Echinidae.

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.