Stylocidaris efflens Mortensen 1827

Family: Cidaridae

Order: Cidaroida

Locality: Philippines, Aliguay Island, deep water, 2006

Dimensions: ca. 35mm Ø (test)
longest spine ab. 70 mm


I got this specimen from a friend as Stylocidaris effluens Mortensen. Trying to prove this taxon, I remarked, that Mortensen in his Monograph of the Echinoidea I, Cidaroida, p. 368, gave only a very short description of 7 lines without any plate. Nevertheless, following this description, 9-10 rather coarsely serrate, sharp, longitudinal ridges on the primary spines should be present. As one may see in the left lower corner there are less than 9-10 ridges. What is your opinion?