Coronaster briareus (Verrill 1882)

Coronaster briareus (Verrill)

Asterias briareus Verrill, 1882:220; 1884:659; 1895:209. cf. “Asterias volsellata”.–Nutting, 1895:168, fig. 3.

Coronaster briareus Verrill, 1915:31, pl. 1: figs. 1, 2, pl. 9: figs. 4–4c.–Gray, Downey, and Cerame-Vivas, 1968:158, fig. 37.

This species has a small disc and eleven (9–12) long, slender arms. The disc is well covered with large, irregularly shaped and arranged plates, most of them bearing one or two long aciculate spines encircled by a dense wreath of small, crossed pedicellariae.

Elsewhere on the disc are large, isolated, straight, spatulate unguiculate pedicellariae. The madreporite is small, round, smoothly convex, and covered with deep gyri. The arms are high and inflated near the base, and the skeleton is reduced to a carinal row of lobate plates connected by long, slender, transverse ossicles to similar superomarginals, which in turn are connected by elongate lobes to trilobate inferomarginals. The inferomarginal plates are connected to one another by imbricate secondary plates. Most of the carinals, superomarginals, and inferomarginals, and a few of the secondary connective plates bear a long, slender, aciculate spine with a dense wreath of small, crossed pedicellariae encircling it. Between the narrow plates, the meshes are large, square, and contain a few papulae. The adambulacral plates bear two long, slender, divergent spines without pedicellariae. Within the groove, and also elsewhere on the surface, are large, solitary, straight unguiculate pedicellariae, expanded and spatulate near the tip, like little clasped hands. Smaller straight pedicellariae are also present. The large tube feet are in two rows. The mouth plates bear a large acicular oral spine and a smaller marginal spine, as well as a number of small, straight pedicellariae. Behind the mouth plates, two or three adambulacral plates are united across the interradius.

The peristome is wide open, and there is a rather broad peristomial membrane. Within the peristome of the specimen before me were two tiny crabs of the family Calapidae.

The known distribution of this species is from New Jersey to the Florida Keys, in 31–373 fathoms.

MATERIAL EXAMINED.–Alaminos Station 20/65-A-9 (1) [R=125 mm, r=7 mm, Rr=1:1.3].

In this order, the disc is more or less domed, with a regular arrangement of enlarged primary plates. There is a prominent median carina on the arms, and all arm plates are in compact and imbricating longitudinal and transverse series. The mouth frame is deeply sunken in the actinostome. The adambulacral plates are alternating carinate and noncarinate, and at least some of the tube feet are large and conical, with a tiny suckered disc. There is but one living family in the order.

The disc is small, and the five arms are long, slender, and tapering. The dorsal disc plates are enlarged, in a regular arrangement of primary radials, interradials, centrodorsal, and sometimes additional plates. There is a prominent row of carinal plates along the midarm, and the other arm plates are in regular longitudinal and transverse series; in most specimens, the number of rows decreases from base to arm tip. The adambulacral plates are alternately carinate and noncarinate. Superambulacral plates are present in all zoroasterids, although they may be present only proximally in most genera, and in Zoroaster they are greatly reduced. Large, duck-billed pedicellariae are present in most genera, but may be absent in Mammaster. Small, straight pedicellariae are numerous.

The tube feet are in four rows proximally, two distally; within the peristomial cavity, they are straight, with a large suckered disc, but on the arms they become stout and conical, with a very small suckered disc.

Coronaster briareus is a species of starfish in the family Asteriidae. It is fast moving and grows to nearly 30 cm. As a defense mechanism it can shed its legs, which later regenerate. This species has an established population in the Maltese waters.

Known from seamounts and knolls