Pteraster personatus Sladen 1891

Pteraster personatus Sladen

Pteraster personatus Sladen, 1891:694, pl. 27: figs. 1–5.–Bell, 1893:94.–Koehler, 1896a:447; 1896b:49; 1907:24.–Nichols, 1903:251.–H. L. Clark, 1908:285 [in key].–Fisher, 1911a:369 [in key].—Farran, 1913:23.

Pteraster reductus Koehler, 1907:25; 1909b:96, pl. 3: figs. 8, 9, pl. 20: fig. 10.–Grieg, 1932:28, pl. 5: figs. 6, 7.

This substellate species has a broad disc and five broad-based arms which taper to an acute point. The dorsal membrane is fine and lacy, with many small spiraculae. The abactinal plates are cruciform, with the lateral extensions flattened and broadly truncate; they are not as long as the tall pedicel, which is expanded at the top, like a tall, attenuate, inverted cone. The pedicels bear 10–25 fine, hairlike, glassy spines which are not quite as long as the pedicel. These spines cross over and mingle with the spines of adjacent plates, so the whole abactinal surface appears to be covered with dense, matted fur.

The valves of the moderate-sized osculum are supported on five large fan-shaped pedicels and consist of a great number of fine long spines. There is a narrow but distinct lateral fringe visible from the abactinal side. The actinal membrane is supported by 18–25 long actinolateral spines which meet in midinterradius. There is frequently a smaller, finer supplementary spine embedded in the membrane beside the actinolateral spine. The adambulacral furrow spines are 3–7 (usually five), webbed together in a curved series; these spines are long, acute, and subequal. The high, plowshare-shaped mouth plates bear a marginal series of 5 or 6 long webbed spines similar to but longer than the adambulacral furrow spines; there are no suboral spines, the face of the mouth plate being quite bare.

Sladen and others have reported this species off the coast of Ireland; I am convinced, although I have not examined his types, that Koehler’s Pteraster reductus, from the Azores, is a juvenile of this species; he based his species on the smaller size and longer spines (correlative characters in asteroids), and on the presence of six, instead of five, adambulacral spines. As noted above, the number of adambulacral spines is variable.

MATERIAL EXAMINED.—Alaminos Station 87/69-A-11 (1) [R=70 mm, r=28 mm, Rr=1:2.5].