Histocidaris species

Family: Histocidaridae

Order: Cidaroida

Locality: Philippines, off Balicasag Island, 208

Dimensions: ab. 82 mm Ø
longest spine ab. 140 mm


The shown test is broken and because of missing parts only partly re-glued (backside). Single spines and lantern are from this specimen.

Primary tubercles perforate and crenulate. Oral primaries curved and strongly serrated, the lower ones ending tapering in a non serrate point, the upper ones sometimes ending with a concavity. Cylindrical ambital primaries cut off or ending in a conspicuous, mostly flattened crown. Length of ambital spines up to 1.5 to 1.6 x the horizontal diameter. Upper primaries shorter and tapering . Colour of primaries witish with a brown collar with increasing diameter towards the ring. Primaries between oral part and ambitus sometimes with coarse serration in the outer part.

Studying "A Monograph of the Echinoidea, I, Cidaroida, 1928, Th. Mortensen" I found no one species combining all the mentioned features. For example: Primary spines of Histocidaris elegans are very long (2,5-3,0 h.d.). The only species, for which a crown has been mentioned, is Histocidaris nuttingi, but unfortunately pictures of the test and the spines, respectively, are missing.

It has surely to be taken into account, that Mortensen had for some species only very few specimens or only the description of other authors. Thus it could easily be, that the one or other feature is subject to variations, not to mention the possibility of new species or hybrids.

Is there anyone, who has more information?