Astropecten marginatus 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 : 15-18

Astropecten marginatus Gray, 1840

Figures 6–7

Astropecten marginatus Gray, 1840: 181 .

Astropecten marginatus — Brito 1962: 3; 1968: 7, pl. 4, fig. 1; Nomura & Fausto Filho 1966: 19; Lima-Verde 1969: 11; Carrera- Rodriguez & Tommasi 1977: 88–89; Tommasi et al. 1988: 5; Clark & Downey 1992: 41–42, fig. 10e, pl. 11A–B; Gondim et al. 2008: 155; Ventura et al. 2008: 177–178; Lima & Fernandes 2009: 58; Magris & Deìstro 2010: 59; Xavier 2010: 75; Gondim et al. 2014: 22–24 , figs. 6a–e, 12b; Guilherme & Rosa 2014; Fernandez et al. 2017; Bueno et al. 2018: 177, fig. 6; Gurjão & Lotufo 2018: 10; Miranda 2018: 14; Patrizzi & Dobrovolski 2018: 182; Torres & Torres 2019: 412; Turra et al. 2019.

Astropecten richardi — Perrier 1875: 372.

Material examined (21 specs, 10–50 mm R). BRAZIL. Bahia, Santa Cruz de Cabrália (16°14’– 16°15’S; 38°00’– 38°58’W)— 7 m, 16.xi.2010, 5 specs, R 11–25 mm ( MZUSP 2100 ); 6 m, 16.xi.2010, 6 specs, R 10–28 mm ( MZUSP 2101 ); 7 m, 16.xi.2010, 5 specs, R 30–50 mm ( MZUSP 2100 ); 6 m, 16.xi.2010, 5 specs, R 30–40 mm ( MZUSP 2101 ) .

Description (R 30–50 mm). Disc broad and flattened, arms short and flattened ( Fig. 6A–C ); R/r 3.3; 39 SM plates (R 50 mm); R/SM# 1.3. Abactinal region covered by paxillae as follows: proximal region of arms and disc with 10–12 central and 15 peripheral spinelets ( Fig. 6D ), midline region of arms with 5–8 central and nine peripheral spinelets, and distal region of arms with 1–3 central and seven peripheral spinelets. Madreporite large, not hidden by paxillae ( Fig. 6E ). Marginal plates horizontal and elongated. Superomarginal plates without spines and covered by granules: central granules robust, peripheral granules elongated, hyaline and thin. Inferomarginal plates projected beyond superomarginal plates. Fringe with two layers of spines, parallel, top layer with two spines of equal size, and a third proximal 3x smaller and thinner ( Fig. 6G ); bottom layer with 4–5 small spines, proximal spine smaller and thinner ( Fig. 6I ). Actinal region of inferomarginal plates lacking squamules; central region naked, sometimes with long spines similar to lateral fringe spines ( Fig. 6J ). Three adambulacral spines forming single line, central spine longer than adjacent ones ( Fig. 6K ). One large subambulacral spine in center of plate, largest spine in adambulacral plate, surrounded by acicular spinelets; spinelets between large spine and furrow spines. Oral spines flattened with blunt tip ( Fig. 6F ). Pedicellariae absent.

Ontogenetic variation (R 10–28 mm). Average R/r 3.0; 22 SM plates (R 20 mm); R/SM# 1.1. Proximal paxillae with 3–5 central and 8–10 peripheral spinelets ( Fig. 7C ), distal paxillae with 0–1 central and 4–5 peripheral spinelets. Inferomarginal fringe with two layers as in larger specimen, but proximal spine in top layer 5x smaller than adjacent spines, and bottom layer with 3–4 small spines, proximal spine smallest ( Fig. 7F ). Three adambulacral spines forming single line, central spine largest in adambulacral plate ( Fig. 7E ). Second subambulacral row as in larger specimen, with central spine largest than adjacent spines, but not largest in adambulacral plate; third row with 2–4 sub-equal spines.

Coloration. Abactinal surface greyish in center of disc and arms, margins orangish to creamy; inferomarginal spines fade from a bluish-grey base to creamy tips. Specimens in ethanol are pale brown.

Distribution. Gulf of Mexico, Mexico, Dominican Republic, Puerto Rico, Costa Rica, Colombia, Venezuela, Guyana, Suriname, French Guyana ( Walenkamp 1976; Clark & Downey 1992; Alvarado et al. 2008; Benavides- Serrato et al. 2005, 2011; Pawson et al. 2009, Alvarado & Solís-Marín 2013). BRAZIL: Amapá, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Bahia, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, Rio Grande do Sul ( Bernasconi 1955; Tommasi 1958; Brito 1962; Lima-Verde 1969; Netto 2006; Gondim et al. 2008; Pelaes 2008; Lima & Fernandes 2009; Xavier 2010; Gondim et al. 2014; Bueno et al. 2018; Miranda 2018; Torres & Torres 2019; Turra et al. 2019). Depth. 1–130 m ( Clark & Downey 1992).

Biological notes. This species lives in muddy, sandy and rubble bottoms ( Alvarado & Solís-Marín 2013) and most likely feeds during the day, preferably on gastropods, bivalves and crustaceans ( Bitter 1984; Zoldan 2005; Guilherme & Rosa 2014; Fernandez et al. 2017). In Caraguatatuba Bay, São Paulo, A. marginatus lives in sympatry with L. senegalensis , where they partition food resources ( Fernandez et al. 2017). The reproductive cycle of A. marginatus in this region is annual and spawning happens mainly during the rainy season ( Turra et al. 2019). Netto (2006) found many specimens gathered in shallow pools at night with 2–5 arms facing upwards, possibly engaged in gas exchange as the exposure of the tube feet into the water column should increase its breathing surface ( Farmanfarmaian 1966).

Astropecten marginatus is classified as “Vulnerable” (baseline data indicate a reduction in population by at least 30% over the next 100 years) by the Ministry of the Environment ( MMA 2018). According to Gurjão & Lotufo (2018), its harvesting in Brazil is currently prohibited.

Holotype. Gray (1840, p. 178) mentioned that the specimens he described were deposited in the collections of the Zoological Society of London (especially South American specimens collected by Mr. Hugh Cuming) and of the British Museum, where he worked. However, Andrew Cabrinovic told us that the type has not been found at the NHM-UK (pers. comm. on 20 Feb 20).

Type locality. Not reported by Gray (1840).

Figures

FIGURE 6. Astropecten marginatus Gray, 1840. (A) Specimen in situ (not collected; photo credit: Cláudio Sampaio). Specimen (R 50 mm) (MZUSP 2100): (B) abactinal and (C) actinal view of body; (D) proximal paxillae; (E) madreporite; (F) oral region; (G) abactinal view of inferomarginal fringe spines (proximal region to the right); (H) terminal region of the arm showing terminal plate; (I) second row of inferomarginal spines, actinal view (proximal region to the right); (J) actinal view of inferomarginal plates; and (K) ambulacral furrow (proximal region on the right). Scale bars: B–C, 20 mm; D–J, 1 mm; K, 2 mm.

FIGURE 7. Specimen (R 20 mm) of Astropecten marginatus Gray, 1840 (MZUSP 2100): (A) abactinal and (B) actinal view of body; (C) proximal paxillae; (D) madreporite; (E) ambulacral furrow (proximal region on the right); (F) actinal view of inferomarginal plates (proximal region to the left); (G) terminal region of the arm showing terminal plate; and (H) oral region. Scale bars: A–B, 10 mm; C–H, 1 mm.