Calyptraster personatus (Perrier 1885)

Calyptraster personatus (Perrier)

Cryptaster personatus Perrier, 1894:191, pl. 14: fig. 3.

Calyptraster personatus.–Madsen, 1947:3, figs. 1–2.

The depressed form of this species is broadly stellate and the abactinal surface is plane. There is a sharp ambital demarcation between the actinal and abactinal surfaces. The supradorsal membrane is strong, muscular, and gelatinous, and spiraculae are of moderate size and numerous. The dorsal paxillar columns are short and robust and bear a crown of 4–6 short, blunt, divergent spines which support the membrane but neither protrude through it nor raise it in peaks. The central osculum is surrounded by a ring of short spines, and the five large triangular valves consist each of 11 or 12 spines webbed together, the shortest at either end and the longest in the middle. The actinal membrane is supported by eighteen or more sturdy, slightly flattened actinolateral spines with blunt (or even expanded) tips, the sixth or seventh being the longest. The actinolateral spines do not meet in the interradius. There are four short, slender, acute adambulacral furrow spines in oblique series, partially webbed by a delicate membrane; the webbing does not extend to the actinolateral spine, and there is a distinct hiatus between the furrow spines and the actinolateral spine.

The mouth plates are small and nearly concealed by 3 or 4 pairs of huge, clavate, thorny-tipped sub oral spines (Sladen and Madsen were inclined to consider the anterior pair as epioral, but I believe that, because their character and position are the same as the two or three pairs behind them, they must be considered suborals). Well within the mouth and on the side margin of each mouth plate is a single small acute spine (sometimes two).

This specimen establishes beyond a doubt that, despite Madsen’s speculations, C. personatus and C. coa are separate and distinct species. Madsen calls C. coa the “western Atlantic species” and C. personatus the “eastern Atlantic species”; this species has hitherto been reported only from the Azores and the Madeira Islands, from 2,150–2,995 meters.

MATERIAL EXAMINED.—Oregon Station 2567 (1) [R=20 mm, r=10 mm, Rr=1:2].

This family is characterized as having small mouth plates, not spade shaped or plowshare shaped. The ambulacral grooves are narrow, and the marginal plates are large and blocklike. The abactinal skeleton is reticulate or imbricate, and the actinal plates are in regular transverse rows, with one or two large spines or a group of small spinelets.

Only one species, of the monotypic genus Leilaster, is represented in the Caribbean; all other members of the family are confined to the polar regions.

Leilaster A. H. Clark

Leilaster A. H. Clark, 1938:1–7. [Type, by original designation, Korethraster radians Perrier.]