Calymne, THOMSON, 1877

Saucede, Thomas, Mironov, Alexander N., Mooi, Rich & David, Bruno, 2009, The morphology, ontogeny, and inferred behaviour of the deep-sea echinoid Calymne relicta (Holasteroida), Zoological Journal of the Linnean Society 155 (3), pp. 630-648 : 632

GENUS CALYMNE THOMSON, 1877

Diagnosis

Test of adults very high, ovoid in aboral view, and compressed laterally with low ambitus; anterior end rounded without frontal groove; posterior end almost vertically truncated. Large spoon-shaped spines present on plastronal area; frills of large paddleshaped spines around periproct and aborally on the posterior end; subanal tuft of large pointed spines.

Other significant features are important in identification of the genus but are present in other holasteroids and therefore not diagnostic for Calymne alone. These are as follows. Orthosternous plastron with small labrum in contact with sternal plate; interambulacra 1 and 4 meridoplacous, interambulacra 2 and 3 amphiplacous in adults; anterior and posterior pairs of genital plates separated by pair of ocular plates; two gonopores on genital plates 2 and 3. Uniporous ambulacra. Peristome flush with test; periproct supramarginal, located at top of posterior face. Marginal orthofasciole crossing plates 5.a.4 and 5.b.5. Rostrate pedicellariae of three types; ophicephalous pedicellariae umbrella-shaped; triphyllous pedicellariae present; tridentate and globiferous pedicellariae absent.

Genotype and only known species: Calymne relicta .