Astropecten antillensis Lu ̈tken, 1860

Figures 2–3

Astropecten antillensis Lu ̈tken, 1860: 47.

Astropecten antillensis — Clark & Downey 1992: 29–30, figs. 9c, 11c, d, pls 9C, D; Benavides-Serrato et al. 2011: 114; Williams et al. 2013: 456; Nisperuza et al. 2016: 115; Soaréz 2016: 78; Borrero-Peìrez et al. 2019: 4; Cunha et al. 2020: 47, fig. 9.

Material examined (3 specs, 20–43 mm R). BRAZIL. Bahia (12°52’– 12°56’S; 38°12’– 38°30’W)— Busca Vida beach, Guarajuba, 45 m, ii.2008, 1 spec, R 20 mm (UFBA 949). Salvador: Plataforma beach, 16 m, 27.ix.2010, 1 spec, R 21 mm (UFBA 1183); Porto beach, 13 m, vi.2012, 1 spec, R 43 mm (UFBA 1620) .

Comparative material. VIRGIN ISLAND. St. Thomas, 4 specs, R 10–56 mm (NHMD 76172, syntypes) .

Description (R 43 mm). Disc half size of arms; R/r 2.5; 22 SM plates; R/SM# 1.95. Arms long and narrow (Fig. 2A–C). Abactinal region covered by paxillae with 1–5 central and 10–12 peripheral spinelets (Fig. 2D). Number of paxillae spinelets increases toward center of disc. Madreporite small, partially hidden among paxillae (Fig. 2D). Superomarginal and inferomarginal plates organized in one row each; inferomarginal plates not projected beyond superomarginal plates. Superomarginal plates covered by spines, fine granules and spinelets. First superomarginal plate with one spine, others with two spines (Fig. 2E). Spine on first plate twice as large as spines from other plates. In plates with two spines, inner spine smaller than outer spine. Inferomarginal plates separated by a gap. Fringe with two layers of flattened and pointed spines, oblique, top layer with two large spines of equal size and another thinner and smaller spine (Fig. 2F), bottom layer with three small spines. Actinal surface of inferomarginal plates lacks squamules (short, flat, scalelike spines; from Cobb et al. 2019); central region naked, sometimes with long spines similar to lateral fringe spines (Fig. 2H). Three equal-sized adambulacral spines forming a single row. Subambulacral row with three spines, central spine larger than adjacent ones (Fig. 2I); sometimes a second row with 1–3 spines present. Oral spines with broad, blunt tip (Fig. 2G). Pedicellariae absent.

Ontogenetic variation (R 20–21 mm). Average R/r 4.1; 19 SM plates (R 20 mm); R/SM# 1.0. Paxillae with 1–3 central and 5–9 peripheral spines (Fig. 3D). Inferomarginal plates project beyond superomarginal plates (Fig. 3E). Superomarginal plates with only one spine; spine on first superomarginal plate relatively larger than that of larger specimen (Fig. 3A, F). Actinal region of inferomarginal plates with fewer squamules than those of larger specimens.

Coloration. Yellowish body with white inferomarginal fringe; Caribbean specimens are yellowish, reddish and orange in situ (Clark & Downey 1992; Benavides-Serrato et al. 2005); white or pale brown in ethanol.

Distribution. Gulf of Mexico, Cuba, Antilles, Puerto Rico, Colombia (Sladen 1889; Bayer et al. 1970; Clark & Downey 1992; Abreu-Pérez et al. 2005; Williams et al. 2013; Nisperuza et al. 2016; Soaréz 2016; Borrero-Peìrez et al. 2019). BRAZIL: Bahia and possibly Trindade Island (John 1948; Cunha et al. 2020). Depth. 3–278 m (Clark & Downey 1992).

Biological notes. In Bahia, Astropecten antillensis lives in nutrient-poor regions with sandy and muddy bottoms. This species can also be found in rubble bottoms (Zoppi de Roa 1967; Alvarado & Solís-Marín 2013).

Syntype. NHMD 76172 [previously as ZMUC AST 4], 76371 (Tom Schiøtte, per. comm) .

Type locality. St. Thomas, Virgin Islands.

Remarks. John (1948) noticed that some of the specimens identified as A. brasiliensis by Sladen (1889) were actually A. antillensis; John’s publication was the first record of this species in Brazil. H.L. Clark (1901) most likely misidentified the Astropecten specimens collected in Puerto Rico because in his identification key, he reported that specimens of A. antillensis do not have spines on marginal plates (given that Clark mentioned in the description following the key that the specimens had inferomarginal spines, “marginal” probably referred to the superomarginal plates).