Ophidiaster guildingi Gray, 1840

Cunha, Rosana, Martins, Luciana, Menegola, Carla & Souto, Camilla, 2021, Taxonomy of the sea stars (Echinodermata: Asteroidea) from Bahia State, including ontogenetic variation and an illustrated key to the Brazilian species, Zootaxa 4955 (1), pp. 1-78 : 48-51

Ophidiaster guildingi Gray, 1840

Figures 26–27

Ophidiaster guildingii Gray, 1840: 284 .

Ophidiaster guildingii — Tommasi & Aron 1988: 3; Hendler et al. 1995: 79, fig. 22; Madeira et al. 2019: 93–94.

Ophidiaster guildingi — Clark & Downey 1992: 281, fig. 44c, d, pl. 69A, B; Benavides-Serrato et al. 2011: 176; Sandino et al. 2017: S294; Borrero-Peìrez et al. 2019: 5; Cunha et al. 2020: 41 , fig. 6; Mah 2020b: 238 , fig. 18A–D.

Material examined (3 specs, 7–22 mm R). BRAZIL. Bahia, Abrolhos, Minerva Seamount (17°03’S, 37°37’W)— 69 m, 18.viii.2012, 3 specs, R 7–22 mm ( MZUSP 2102 ) .

Comparative material. BRAZIL. Espírito Santo: Trindade Island (20°29’– 20°32’S; 29°19’– 29°20’W)— Enseada dos Portugueses, 12 m, 15.vii.2013, 1 spec, R 9 mm ( MZUSP 1563 ); Enseada do Príncipe, Pedra da Garoupa , 10.4 m, 16.vii.2013, 1 spec, R 25 mm ( MZUSP 1576 ); Enseada das Orelhas , 8.9 m, 8.i.2015, 1 spec, R 62 mm ( MZUSP 1570 ) .

Description of largest specimens (R 17–22 mm). Disc small; average R/r 4.9 ( Fig. 26A–B ). Five long, cylindrical, constricted at base. Madreporite subcircular ( Fig. 26D ), evident in interradial area. Anus conspicuous in center of disc, surrounded by 10 spines. Terminal plate round, smaller than arm diameter, with about 8 tubercles ( Fig. 26G ). Abactinal plates ( Fig. 26C ) cruciform, imbricated, covered by flattened granules, and arranged in seven regular rows. Papular areas forming regular rows parallel to abactinal plates; with 4–8 pores proximally ( Fig. 26C ) and 3–5 pores distally. Marginal plates similar to abactinal plates. One row of imbricate actinal plates; actinal papular areas with 4–6 papular pores ( Fig. 26H ). Each inferomarginal plate connected to two adjacent actinal plates via a rod-like plate. One row of adambulacral spines, two subequal spines per plate ( Fig. 26F ). One subambulacral spine per plate; spine flattened, tapering, twice as large as adambulacral spine. Space between adambulacral and subambulacral spines ( Fig. 26E ). Oral spines ( Fig. 26E ) similar to adambulacral spines. Tube feet in two rows, sucking disc with perforated plates. Pedicellariae absent.

Ontogenetic variation (R 7 mm). Average R/r 2.3. The specimen has short and wide arms, not constricted at the base ( Fig. 27A–B ), and a relatively large terminal plate forming the tip of the arm ( Fig. 27G ). The number of spines, tubercles, and papular areas are reduced in some areas, the anus is surrounded by 7–9 spines, terminal plates have 4–5 tubercles, papular areas have 1–3 pores in the abactinal region, and 1–2 pores in the actinal region. Also, abactinal plates are round and not imbricated ( Fig. 27C ), and adambulacral spines equal ( Fig. 27E ).

Coloration. No record of coloration of in vivo specimens from this region, but specimens from Trindade Island are dark brown ( Cunha et al. 2020). Juveniles from the Caribbean are purple ( Hendler et al. 1995). Specimens in ethanol are pale brown.

Distribution. Eastern Atlantic: Cape Verde, Gulf of Guinea, Ascension Island. Western Atlantic: U.S.A. (FL, GA, TX), Bermuda, The Bahamas, Mexico, Cuba, Belize, Turks and Caicos, Anguilla, Dominican Republic, Puerto Rico, Virgin Islands, Trinidad and Tobago, Antilles, Nicaragua, Panama, Colombia ( Pawson 1978; Clark & Downey 1992; Entrambasaguas 2003; Sandino et al. 2017; Borrero-Peìrez et al. 2019; Mah 2020b). BRAZIL: Bahia, Trindade Island, Rio Grande do Sul ( Tommasi 1970; Carrera-Rodriguez & Tommasi 1977; Tommasi & Aron 1988; Cunha et al. 2020). Depth. 0–445 m ( Mah 2020b).

Biological notes. In Bahia, this species is found in rubble and coral reef ecosystems, calcareous rocks and gravel ( Tommasi & Aron 1988). Although O. guildingi is not widely distributed, it is generally abundant locally. Ophidiaster guildingi is a slow-moving species ( Hendler et al. 1995) and can reproduce asexually and regenerate a new individual from a single arm ( Haeckel 1878). The specimens from Bahia did not show signs of asexual reproduction.

Holotype. The type specimen of O. guildingi has not been found ( Clark & Downey 1992).

Type locality. St Thomas, Virgin Islands ( Clark & Downey 1992).

Remarks. This species is generally small, growing only up to R 62 mm; according to H.L. Clark (1933), O. guildingi reaches maturity at R 45 mm. As noted above, the number of pores per papular area varies with ontogeny. Specimens from Trindade Island with R 9 mm have 1–2 pores, with R 25 mm have 3–6 pores and with R 62 mm have 5–12 pores. At R 33 mm, specimens have 5–12 pores ( Downey 1973), and the maximum number of pores is 15 ( Clark & Downey 1992). Clark & Downey (1992) also noted the rare occurrence of pedicellariae in large specimens, but Cunha et al. (2020) did not find pedicellariae in the specimens from Trindade Island.

Ophidiaster guildingi differs from O. alexandri , O. bullisi and O. reyssi by having only one row of actinal plates (vs. 3–5 rows in O. alexandri ; two rows in O. bullisi ; and four rows in O. reyssi ); from O. bayeri by having only one row of subambulacral spines (vs. two rows); from O. ophidianus by having up to 15 pores per papular area (vs. more than 20 pores) and flat and tapering spines subambulacral spines (vs. cylindrical and blunt) ( Clark 1921; Clark & Downey 1992; Madeira et al. 2019).

Figures

FIGURE 26. Specimen (R 22 mm) of Ophidiaster guildingi Gray, 1840 (MZUSP 2102): (A) abactinal and (B) actinal view of body; (C) abactinal plates and papular pores; (D) madreporite; (E) oral region; (F) ambulacral furrow (proximal region on the right); (G) terminal region of the arm with ocular plate; and (H) actinal papulae. Scale bars: A–B, 10 mm; C–H, 1 mm.

FIGURE 27. Specimen (R 7 mm) of Ophidiaster guildingi Gray, 1840 (MZUSP 2102): (A) abactinal and (B) actinal view of body; (C) abactinal plates and papular pores; (D) madreporite; (E) ambulacral furrow (proximal region on the right); (F) oral region; and (G) terminal region of the arm with ocular plate. Scale bars: A–B, 2 mm; C–G, 1 mm.