The Echinoid Directory

Contributed by Simon Coppard, October 2006

Coelopleurus (Keraiophorus) undulatus var. polymorphus Mortensen, 1934, p.167

Diagnostic Features	The test is subcircular and has a relatively narrow naked median interambulacral regions that have undulating edges. These are purple, with an undulating lilac line that starts from each genital plate and continues to the ambitus. These naked median regions have red borders, while the test has cream/pink ambulacra and red interambulacra. Primary spines are curved and unbanded. On the dorsal surface they are red distally blending into green proximally. The spine's collar is relatively smooth either side of the dorsal ridge, while the ventral surface has many longitudinal ridges. Secondary spines are slightly club-shaped (not distinctly tapering distally). Ophicephalous pedicellariae occur in two forms. The larger form has moderately constricted valves aborally and unconstricted orally. The smaller form, which occurs primarily on the aboral surface has very constricted valves.
Distribution	Kyushu, Japan.
Classification and/or Status	Arbacioida, Arbaciidae, Coelopleurus
Remarks	This variety differs from C. (K.) undulatus in having sharply defined naked interambulacral regions, and by having two forms of ophicephalous pedicellariae. It differs from C. (K.) undulatus var. ruber by not having broad naked interambulacral regions, by having slightly club-shaped secondary spines, and by the presence of two forms of ophicephalous pedicellariae. It is likely that this is a hybrid specimen of C. (K.) undulatus x C. (K.) undulatus var. ruber. A second specimen labeled as C. (K.) undulatus var. polymorphus is held in the Zoological Museum, Copenhagen. This clearly differs from the holotype of C. (K.) undulatus var. polymorphus, and is very similar to the holotype of C. (K.) undulatus var. ruber. It differs only in that the naked interambulacral reigions are bisected adambitally along the suture line. This would appear to be within the normal limits of variation within C. (K.) undulatus var. ruber. Mortensen, T. 1934a. New Echinoidea. (Preliminary Notice.) . Videnskabelige Meddelelser fra Danks naturhistorisk Forening i Kobenhavn 98: 161-167.