Henricia antillarum Perrier 1881

Henricia antillarum (Perrier)

Cribrella antillarum Perrier, 1881a:8; 1884:207, pl. 3: fig. 3.

Henricia antillarum.–Verrill, 1914:210; 1915:46.–H. L. Clark, 1941:56.

Henricia microspina Verrill, 1915:48.-H. L. Clark, 1941:57.

This species has a small disc and five long, slender, emaciated-looking arms. The arms are broad at the base, but beyond the basal one fourth or one fifth portion they are extremely attenuate. The abactinal plates are mostly C-, Y-, or X-shaped, with many small round plates scattered among them. They are covered with minute, glassy-tipped spinules, mostly in irregular rows on the plates. The papular pores are large and the papulae are single. Superomarginal plates are smaller than the nearly square inferomarginals, but distally the two series tend to become more equal. They bear spinules like those of the abactinal plates. A single row of actinals may extend a short distance beyond the disc; the interradial actinals are few, crowded, and small. Papular pores occur to the adambulacral plates. Actinal spinules are smaller than those of the abactinal surface.

The adambulacral plates have a sharply carinate furrow face bearing 2–5 small furrow spines, one above the other. On the furrow margin are 4–6 long, stout, blunt spines, and the actinal face of the plate bears up to twenty short, stout, aciculate spinules, becoming increasingly similar to those of the inferomarginals. The long narrow mouth plates bear one or two stout, blunt preoral spines at the apex and 2 or 3 minute spines on the side margin, well within the mouth. Behind the preoral spines are 2–5 similar spines, not quite so stout. The rest of the plate is covered with short, stout, aciculate spinules. The single madreporite is rounded, raised, and covered with spinules.

I believe Verrill’s Henricia microspina is the same as H. antillarum, despite H. L. Clark’s assertion that the two species were distinguishable on the basis of length of spinules and size of skeletal meshes. I have examined the types of both species and can find no specific differences. Allowing for the difference in size of the two specimens (H. antillarum, R=54 mm, vs H. microspina, R=20 mm), there is no essential difference in the length of spinules or size of mesh of the skeleton. The number, size, type, and arrangement of the adambulacral spines, and the general form of the starfish seem to be more reliable characters for distinguishing the species of Henricia.

However, there is a third species of Henricia in the Caribbean. Because the types of so many species are not available, or are in very poor condition as regards essential features, it is probably not desirable to add still another name to this already overcrowded genus without more material.

Henricia antillarum probably does not occur south of about 15° N. Its depth range is 175–390 fathoms.

MATERIAL EXAMINED.—Alaminos Station 25/70–A–10 (1) [R=55 mm, r=10 mm, Rr=1:5.5], Oregon Stations: 489 (1) [R=26 mm, r=4 mm, Rr=1:6]; 491 (1) [R=28 mm, r=5 mm, Rr=1:5.5].

Henricia species

This species has a small disc and five long, tapering, cylindrical arms, thick at the base, and slightly constricted. The abactinal plates are thick, elongate, and imbricate. There are also some small irregularly rounded plates. All bear numerous small, divergent, thorny-headed spinules. The meshes of the skeleton are large, as are the papulae, and the papulae are usually single, but there may be up to four per mesh. The superomarginal plates are small and triangular, and proximally they may be separated from the inferomarginals by a few small rounded plates. The inferomarginals are broader than long, and about twice the size of the superomarginals. The spinulation is like that of the abactinals. The adambulacral plates are about twice as broad as long. On the broadly carinate furrow surface, they bear, deep within the furrow, about six short, stumpy spines, roughly in two vertical rows of three each. Above them, on the outer furrow margin of the adambulacrals, are about 6–10 long, thick, blunt spines; owing to the sloping face of the furrow margin, they do not reach much beyond the height of the short, thick, thorny spinules on the actinal face of the plate, which are numerous but spaced. The spines on the apical margin of the mouth plates are thick, blunt, and crowded.

The plates themselves are long, narrow, and triangular, and the actinal face is evenly covered with short, thick, thorny, spaced spinules. The madreporite is small, round, raised, and covered with radiating gyri; the smaller of the two specimens below had three madreporites.

MATERIAL EXAMINED.—Oregon Stations: 35 (1) [R=30 mm, r=6 mm, Rr=1:5]; 2644 (1) [R=62 mm, r=12 mm, Rr=1:5].

Echinaster Muller and Troschel

Echinaster Muller and Troschel, 1840:102. [Type, by subsequent designation, Asterias seposita Lamarck (non Retzius) (=Asterias sagena Retzius, 1805) (Fisher, 1913:195).]

Othilia Gray, 1840:281. [Type, by original designation, Asterias spinosa Retzius (=Pentadactylosaster spinosus Linck).]

Rhopia Gray, 1840:282. [Type, by original designation. Asterias seposita Retzius (=Pentadactylosaster reticulatus Linck).]

Henricides Verrill, 1914:210. [Type, by original designation, Henricia heteractis H. L. Clark, 1909.]

Thyraster Ives, 1890:329. [Type, by original designation, Echinaster serpentarius Muller and Troschel.]

Disc small, five arms long, more or less cylindrical; spines on plates isolated, never in groups or bundles; patch of glassy tubercles on most principal plates; skeleton an open meshwork of plates connected by secondary plates.

This genus is perhaps the most confusing one occurring in the tropical and subtropical Atlantic. Not only are the species ill-defined, but the genus itself has undergone various taxonomic changes. Fisher (1919), in attempting to define the status of the genus, compounded the confusion by making several unwarranted assumptions and overlooking important references. His arguments for separating the American species from the European ones and placing them in another genus, Othilia, are so involved and seem to me so feeble that it would be preferable to retain Echinaster for these very common Gulf and Caribbean species, a name well known and firmly established in the literature.

In examining the Echinasters in this collection, I found it relatively easy to distinguish what seem to be eight species. Echinaster braziliensis, E. sentus, E. echinophorus, E. modestus, and E. serpentarius could be identified definitely. Rather than add what are probably quite unnecessary names to the genus, the other three species I have distinguished have here been given letters in the hope that this will simplify matters for some future reviser. Of the three species I have been unable to identify, none seem to fit Tommasi’s (1970) new species. E. densispinus or E. nudus.