The Echinoid Directory

• Test depressed and relatively thick.
• Apical disc about 50% test diameter; dicyclic or with narrow periproctal plate separating genital plates. All genital plates similar in size and uniformly covered in granules.
• Interambulacra with 5-8 plates; primary tubercles perforate and non-crenulate; areoles incised, circular and separated on ambital and adapical plates.
• Scrobicular tubercles differentiated; extrascrobicular zones not extensive and covered in dense, heterogeneous tuberculation.
• Ambulacra almost straight. Pore zones incised; pore-pairs sub-conjugate with interporal partition as large or slightly larger than a pore. Marginal series of contiguous primary tubercles and smaller inner series.
• Peristome slightly narrower than apical disc. Ambulacral plates uniserially arranged. Interambulacral series reaching the peristome.
• Spines long, slender and cylindrical; not tapering and sometimes widened and flattened at tip. Neck and collar short; shaft ornamented by longitudinal beaded ribs. Cortical hairs dense.
• Secondary spines flattened and somewhat adpressed.

Recent, East Pacific.

Dorocidaris panamensis Agassiz, 1898, p. 73, by original designation.

• H. panamensis (Agassiz, 1898); recent, Ecuador, Cocos Islands.
• H. dubia (Clark, 1907); Recent, Ecuador.
• H. perplexa (Clark, 1907); Recent, West American coast.
• H. houstonianus Clark, 1938; Recent, Gulf of Mexico.
• H. asteriscus Clark, 1948; Recent, Gulf of Mexico.

Cidaroida, Cidaridae, Cidarinae.

Subjective junior synonym of Tretocidaris(Stylocidaris) (Mortensen, 1909)

Very similar to Tretocidaris (Stylocidaris) differing primarily in the form of its primary spines which have dense, anastomosing cortical hairs, and in lacking a limb on the stalk of its large globiferous pedicellariae. In general test morphology the two are indistinguishable.

Mortensen, T. 1928. A monograph of the Echinoidea. 1, Cidaroidea. C. A. Reitzel, Copenhagen.

Caso, M. E. 1979. Los equinoideos del Pacifico de Mexico. Parte Primera - Ordenes Cidaroidea y Aulodonta. Publicaciones especiales Centro de Ciencias del Mar y Limnologia, Universidad Nacional Autonoma de Mexico 1, 1-103.