Henricia sexradiata (Perrier 1881)

Henricia sexradiata (Perrier)

Cribrella sexradiata Perrier, 1881a:8; 1884:209, pl. 4: fig. 6.

Henricia sexradiata.–Verrill, 1914:371; 1915:47, pl. 11: fig. 7. H. L. Clark, 1941:58.

This small species is the most distinctive Henricia of the Caribbean and Gulf of Mexico, quite apart from its six or more arms. The disc is small and the arms long, rounded, evenly tapering to a subacute point. The irregularly shaped abactinal plates–elongate, lobed, or rounded–imbricate upon one another to form a close reticulum. The papulae are small, and usually there are several to each pore area. The abactinal plates are covered with a dozen or more small, erect, thorny spinules. Both series of marginals are large, distinct, equal, and imbricate; they bear spinules similar to those of the abactinals and are separated from the adambulacral plates by a single row of actinals extending less than one third the length of the arm. Papular pores occur between the marginals and between the inferomarginals and the adambulacral plates. Actinal plates are few and rounded, with papular pores extending to the mouth plates; they bear spinules similar to those of the marginals and abactinals.

The adambulacral plates are broader than long, rectangular, and bear, on the strongly carinate furrow face, three short appressed furrow spines, one above the other, deep within the narrow ambulacral groove. On the outer furrow margin are three stout, thorny, subclavate spines, about twice the length of the actinal spinules, and behind them is a second series of 2 or 3 similar, slightly shorter spines. The actinal face of the plate is covered with spinules similar to those of the marginals. The mouth plates are narrow and triangular, with one or two stout, blunt, flattened preoral spines; the rest of the spinulation is like that of the adambulacral plates. There is usually more than one madreporite, raised, flattened, and bearing numerous spinules. The oculars are small, round, and covered with small thorny spinules. This is a fissiparous species.

This species ranges from the northern Gulf of Mexico to Surinam, in 75–190 fathoms.

MATERIAL EXAMINED.—Oregon Stations: 2289 (1) [R=46 mm, r=6 mm, Rr=1:8 (three long arms, four short arms)]; 36 (1) [R=49 mm, r=10 mm, Rr=1:5 (six equal arms)].

Henricia sexradiata is a species of starfish in the family Echinasteridae. It is native to the western Atlantic Ocean and the Gulf of Mexico.