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The Echinoid Directory

Strongylocentrotus Brandt, 1835, p. 263

[=Euryechinus Verrill, 1866, p. 341 (objective); = Allocentrotus Mortensen, 1942, p. 232 (subjective), type-species Strongylocentrotus fragilis Jackson, 1912, by original designation;  ? = Mesocentrotus Tatarenko & Poltaraus, 1993, p. 70, type species Strongylocentrotus franciscanus (Agassiz, 1863) by original designation. ]

Diagnostic Features
  • Test circular in outline.
  • Apical disc hemicyclic with posterior oculars generally insert (in contact with the periproct).
  • Ambulacra polygeminate, with 5 to 10 pore-pairs to a plate. In the type species pore-pairs are arranged in an oblique row of 5-7 pore-pairs separated by a row of secondary tubercles.
  • All ambulacral plates with single large primary tubercle and smaller secondary tubercles perradially.
  • Interambulacral plates with single primary tubercle and smaller secondary tubercles forming horizontal rows.
  • Ambulacral zones uniform in width; as wide or wider than interambulacral zones around peristome.
  • Spines relatively fine and not larger than 0.5 test diameter.
  • Globiferous pedicellariae with muscular neck and tubular blade, but no lateral teeth.
Distribution
Early Miocene to Recent; Australia, North Pacific and North West Atlantic.
Name gender masculine
Type
Echinus droebachiensis Muller, 1776, by original designation.
Species Included
  • S. droebachiensis (Muller, 1776); Recent, circum-polar, 0-1150 m.
  • S. pallidus (Sars, 1871) [includes S. sachalinicus Doderlein, 1906, and S. echinoides Agassiz & Clark, 1907]; Recent, Arctic coasts (Bering Sea, North Pacific, North Atlantic).
  • S. polyacanthus Agassiz & Clark, 1907; Recent, Bering Sea.
  • S. intermedius (Agassiz, 1863); Recent, Japan.
  • S. pulchellus Agassiz & Clark, 1907; Recent, North West Pacific.
  • S. purpuratus (Stimpson, 1857); Recent, Alaska to California.
  • S. antiquus Philip, 1965; Lower Miocene, Australia.
Classification and/or Status

Camarodonta; Echinoida; Strongylocentridae.

Monophyletic.
Remarks

Resembles Paracentrotus in overall appearance but differs from that taxon in having the posterior ocular plates always broadly insert. The structure of the globiferous pedicellariae also immediately distinguishes these two, Paracentrotus having pedicellariae with an open blade, paired lateral teeth and no muscular neck. Distinguished from the very similar Mesocentrotus by its spines which are smaller and lack the large meshwork core seen in that genus

X-ray tomography of Strongylocentrotus purpuratus: http://www.digimorph.org/specimens/Strongylocentrotus_purpuratus

The oldest specimen attributable to this genus is from the Early Miocene of Australia (Philip, 1965) The genus was revised and the species described by Jensen (1974).

Brandt, 1835 (May). Prodr. Descr. Anim. Rec. actes Acad. Imp. Sci. Petersburg [1834], p. 263.


Jensen, M. 1974. The Strongylocentrotidae (Echinoidea), a morphological and systematic study. Sarsia 57, 113-148.

Philip, G. M. 1965. The Tertiary echinoids of south-eatern Australia III Stirodonta, Aulodonta and Camarodonta (1). Proc. Roy. Soc. Victoria 78, 181-196, pls 26-29.