Red Cushion Sea Star

Oreaster reticulatus (Linnaeus)

Asterias gigas Linnaeus, 1753:114, pl. 9: fig. 1.

Asterias reticulata Linnaeus, 1758:661.–Retzius, 1783: 1805; pl. 14.–Lamarck, 1816:556.

Pentaceros reticulatus.–Gray, 1840:276; 1866:6.–A. Agassiz, 1877:108–112, pl. 16: figs. 6–11.–Perrier, 1878:21, 52, 83.–Viguier, 1879:193, pl. 11: figs. 4–6, pl. 12: figs. 3, 4.–Sladen, 1889:344, 762.–Ives, 1891:339.–Nutting, 1895:52, 187, 202, 212.–Leipoldt, 1895:634.–(incl. P. lapidarius Grube).–Sluiter, 1895:56.–H. L. Clark, 1898a:5, 6; 1901:237.–Ihering, 1898:155.–Conant, 1900.–Duerden, 1900:613, 620.–Tennent and Keiller, 1914.

Oreaster gigas.–Verrill, 1867:278–279; 1868:367.–Lutken, 1859: 64–75.–Rathbun, 1879:149.

Oreaster reticulatus.–Muller and Troschel, 1842:45, pl. 3: fig. 2.–Field, 1893:84.–Doderlein and Hartmeyer, 1910:151–152.–H. L. Clark, 1919:53–55, 71; 1933:22–23.–Boone, 1933:80–82, pls. 41–42.–Doderlein, 1936:319–320, pl. 31: figs. 3–3a.–Engel, 1939:3, 7.–A. H. Clark, I939:442.–Caso, 1944: 248–253, 2 figs.; 1961:59–62, figs. 20–21.–Fontaine, 1953:182, fig.–Breder, 1955: pl. 1: fig. 4.–Bernasconi, 1958b:135–136. pl. 4: figs. 1–2; 1960:25.–Tommasi, 1958:16–17, 32–33, pl. 3: fig. 2.–Madsen, 1959:163, fig. 1.–Brito, 1960:5–6, pl. 1: fig. 3.–Stanek, 1960:49, figs.–Thomas, 1960:167–168.–A. M. Clark, 1962: pl. 2: figs. a-d.–Ummels, 1963:73–81, pls. 3–6.–Gray, Downey, and Cerame-Vivas, 1968:146, figs. 19a-b.

Oreaster lepidosus Grube, 1857.

Asterias sebae Blainville, 1834:240.

Oreaster aculeatus Gray, 1866.

Oreaster reticulate.–Duerden, 1896:285.

Oreaster reticulatus var. bermudensis H. L. Clark, 1944:372–374, figs. 1–2.

This very massive starfish normally has five arms, but may have from four to seven. Linck’s De Stellis Marinis (1733) has a woodcut of Linck in his laboratory examining a four-armed specimen; as he based most of his classification on the number of arms, he described this specimen as belonging to a separate group. The disc is broad and high. The arms are short to moderately long, becoming proportionately shorter with increased size. The primary dorsal plates are thick and irregularly shaped; there is a conspicuous circle of plates in the center of the disc and three irregular rows of plates on each arm. The numerous other primary plates are not in any particular pattern. All the primary plates are connected in a reticulate pattern by small, irregular, or rod-shaped secondary plates. Most primaries bear a large, heavy tubercle or stout spine. Spaces between the reticulations are papular areas, with numerous tiny papular pores. The entire surface, dorsal and ventral, with the exception of the spines themselves, is covered with a moderately thick membrane closely set with small granules. The large tumid superomarginal plates define the ambitus and each bears a very stout, blunt spine. The inferomarginal plates are confined to the ventral surface; they are large and rounded and sometimes bear a short, stout, central spine, but usually the center of the plate bears instead a few enlarged granules. The actinal interradial areas are large, the plates (concealed by granules somewhat larger than those of the dorsum) are tessellate, and many of the proximal ones bear one or more short, stout, central tubercles or spines. One series of actinolaterals continues nearly to the end of the arm. Valvate pedicellariae, set into small cup-shaped plates or granules, are numerous, especially proximally, and small pedicellariae also occur on the dorsal surface. The small, square adambulacral plates bear a furrow series of about five short, flat, subequal spines and the actinal face of the plate bears a large, flat lanceolate spine with, usually, a small spine beside it. The mouth plates are small and armed with heavy blunt spines. The madreporite is of moderate size, flat, smooth, plane, and covered with fine shallow gyri. The young Oreaster reticulatus is not inflated, and the marginals are relatively larger and more conspicuous than in the adult. The variation in shape, from pentagonal to stellate, the differing degrees of inflation of the disc, and the variety of colors, from dark green, brown, dark red, orange and red, and yellow to light tan, make this an extremely variable species.

The species is common in shallow-water grass-and-sand flats from Florida to Brazil; it has also been taken in the Cape Verde Islands, Bermuda, and occasionally occurs as far north as Cape Hatteras.

MATERIAL EXAMINED.–Oregon Stations: 5390 (2) [R=91 mm, r=40 mm, Rr=1:2.3 (height of disc=34 mm)]; 1937 (1) [R=71 mm, r=34 mm, Rr=1:2.2 (height of disc=34 mm)]; 1934 (1) [R=47 mm, r=22 mm, Rr=1:2 (height of disc=22 mm)]; 1938 (1) [R=69 mm, r=30 mm, Rr=1:2.3 (height of disc=29 mm)]; 3603 (1) [R=15 mm, r=7 mm, Rr=1:2 (height of disc=5 mm)]; 5456 (1) [R=15 mm, r=8 mm, Rr=1:2 (height of disc=5 mm)]. Note that all of the above specimens are rather small; this species commonly reaches a size of R=200 mm, r=100 mm, and height of disc=80 mm.

In this family, the disc is small and the arms are usually long and cylindrical. The actinal interradial areas are generally small, as are the marginal plates. The skeleton is tessellate and covered with a granular skin (smooth in Leiaster). The tube feet are in two rows, with well-developed suckers. The ambulacral furrow is narrow.

Among the best understood, taxonomically, of the families of starfishes are the Ophidiasteridae. The genera are clearly defined, and the characteristics used to separate species within the genera are stable and valid. The present comfortable status of this family is due largely to H. L. Clark (1921), whose careful analysis of the group was done with such simple clarity as to make his keys intelligible and useful to all.

It is, therefore, surprising to find A. H. Clark in 1954 confusing Tamaria floridae (he called it Ophidiaster floridae), Ophidiaster alexandri, Ophidiaster pinguis, and Hacelia superba, which he apparently thought all one species, and synonymized under the name Hacelia floridae! I have examined the types of all of these species, and there is no doubt in my mind that they are all valid and distinct.

H. L. Clark himself did not, apparently, examine in any comparative way Linckia bouvieri and Linckia nodosa; he considered L. nodosa a junior synonym of L. bouvieri. The two species are, of course, quite distinct, as I pointed out in 1968.