Astropecten brasiliensis brasiliensis Müller & Troschel, 1842

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 : 11-14

Astropecten brasiliensis brasiliensis Müller & Troschel, 1842

Figures 4–5

Astropecten brasiliensis Müller & Troschel, 1842: 68 .

Astropecten brasiliensis — Tommasi et al. 1988: 5; Manso 1989: 357; Clark & Downey 1992: 32, fig. 9e, pl. 12A, B; Fernandes et al. 2002: 422; Netto 2006: 25–26, pl. 2a, fig. 16a; Ventura et al. 2007: 230; Ventura et al. 2008: 174–175; Lima & Fernandes 2009: 58; Xavier 2010: 75; Miranda et al. 2012: 143–144.; Gondim et al. 2014: 19–20 ; Alitto et al. 2016: 10, figs. 7a–b; Bueno et al. 2018: 176–177, fig. 5; Gurjão & Lotufo 2018: 10; Torres & Torres 2019: 412; Cunha et al. 2020: 49 .

Astropecten braziliensis — Rathbun 1879: 150; Verrill 1915: 173; Tommasi 1970: 6; Magris & Deìstro 2010: 59; Patrizzi & Dobrovolski 2018: 182.

Astropecten armatus brasiliensis — Tommasi 1958: 12–13, pl. 2, fig. 3; 1970: 7, fig. 19; Brito 1962: 3; 1968: 7–8, pl. 4, fig. 3; Lima-Verde 1969: 10; Carrera-Rodríguez & Tommasi 1977: 81–82; Magalhães et al. 2005: 63.

Astropecten riensis — Carrera-Rodríguez & Tommasi 1977: 89; Tommasi & Aron 1988: 3; Tommasi et al. 1988: 5.

Material examined (69 specs, 3–103 mm R). BRAZIL. Bahia (12°45’– 13°56’S; 38°06’– 39°06’W)— Busca Vida beach, 25 m, vii.2003, 1 spec, R 10 mm ( UFBA 1048 ); 45 m, iii.2005, 3 specs, R 4–13 mm ( UFBA 1049 ); 22–45 m, 1.vii–viii.2007, 12 specs, R 4–18 mm ( UFBA 515–520 ); 25–45 m, vii.2008, 9 specs, R 3–19 mm ( UFBA 948 , 1046 ); 25–45 m, vi.2009, 3 specs, R 9–15 mm ( UFBA 1047 , 1073 ); 25–45 m, i.2010, 3 specs, R 6–18 mm ( UFBA 1074–1075 , 1081 ); 25–45 m, viii.2010, 3 specs, R 9–21 mm ( UFBA 1162 ); 45 m, ii.2011, 2 specs, R 12–13 mm ( UFBA 1303 ); 25–45 m, vii.2012, 3 specs R 8 mm ( UFBA 1621 , 1625 , 1721 ). Salvador: off Artista beach, 28–47 m, i.2005, 2 specs, R 3–7 mm ( UFBA 922 , 1095 ); 47–50 m, 15.viii.2005, 7 specs, R 10–18 mm ( UFBA 597 , 599 ); off Jardim de Alá beach, 45–47 m, i.2005, 2 specs, R 6 mm ( UFBA 921 ; 1044); 47 m, 15.viii.2005, 6 specs, R 4–18 mm ( UFBA 598 ); off Rio Vermelho beach, 25 m, 15.ii.2008, 1 spec, R 3 mm ( UFBA 642 ). Vera Cruz : Barra Grande beach, intertidal, 1.xi.1992, 10 specs, R 21–29 mm ( UFBA 40 , 193 ). Boipeba Island : Moreré beach, 30 m, i.2004, 2 specs, R 10–16 mm ( UFBA 940 , 1045 ). Salvador: Ribeira beach, intertidal, 1.iii.2006, 1 spec, R 103 mm ( UFBA 132 ) .

Comparative material. BRAZIL. São Paulo: São Sebastião Island . xii.1915, 4 specs, R 65–125 mm ( NMNH E529 , neotype; MZUSP 2096 ) .

Description (R 103 mm). Arms long and narrow ( Fig. 4A–B, D–E ); R/r 4.7; 41 SM plates; R/SM# 2.5. Abactinal region covered by paxillae with 6–8 central and 12–15 peripheral spinelets. Number of paxillae spinelets increases toward center of disc. Paxillae ( Fig. 4G ) irregularly arranged, being more separated in median region of arms than near or in disc, and more separated in marginal region of arms than in median region of arms. Density of paxilla spinelets decreases from disc to arm tip. Madreporite large (5 cm), not hidden by paxillae ( Fig. 4C, G ). Superomarginal and inferomarginal plates organized in one row each; inferomarginal plates not projected beyond superomarginal plates. Superomarginal plates covered by spines, granules and spinelets. First and second superomarginal plates with one spine ( Fig. 4H ), others with two spines. Spine decreases in size from first to third plate and then remains the same. In plates with two spines, inner spine larger than outer spine ( Fig. 4I ). Inferomarginal plates separated by a gap. Fringe oblique, with two layers of flattened and pointed spines, top layer with two large spines of equal size ( Fig. 4J ), bottom layer with two smaller spines. Actinal region of inferomarginal plates with squamules, and medium and long-sized spines ( Fig. 4K ). Three equal-sized adambulacral spines forming a single row. Subambulacral spines ( Fig. 4L ) in two rows: first row with two unequal spines (distal 2x as large as proximal); second row with 3–5 spines, sometimes grouped. Oral spines with broad, blunt tips. Pedicellariae absent.

Ontogenetic variation (R 3–50 mm). Average R/r 3.8; 19 SM plates (R 21 mm); R/SM# 1.1. Paxillae with 1–2 central and about 7–8 peripheral spinelets, more spaced than in larger specimens. Superomarginal plates without spines or with only one spine ( Fig. 5C ). Some inferomarginal plates with three spines, one 2x smaller than others and located at proximal end of plate ( Fig. 5G ). Adambulacral spines of unequal size; central spine larger than adjacent spines ( Fig. 5E ). Second row of subambulacral spines starts forming in specimens with 25 mm R.

Coloration. Specimen in vivo has lilac abactinal region, pinkish orange actinal region and light pink marginal plates. Specimens in ethanol are pale brown.

Distribution. Caribbean Sea, Venezuela, Uruguay, Falkland Islands, Tierra del Fuego ( Mah 2020a). BRAZIL: Ceará, Rio Grande do Norte, Fernando de Noronha Island, Alagoas, Bahia, Trindade Island, Rio de Janeiro, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul ( Rathbun 1879; Sladen 1889; Verrill 1915; Tommasi 1958, 1970; Brito 1962; Lima-Verde 1969; Walenkamp 1976; Carrera-Rodriguez & Tommasi 1977; Walenkamp 1979; Tommasi & Aron 1988; Fernandes et al. 2002; Netto et al. 2006; Ventura et al. 2007; Miranda et al. 2012; Alvarado & Solís-Marín 2013; Gondim et al. 2014; Alitto et al. 2016; Bueno et al. 2018; Torres & Torres 2019; Cunha et al. 2020). Depth. Intertidal to 66 m ( Alvarado & Solis-Marin 2013; present paper).

Biological notes. The specimens from Bahia were found in sandy, muddy and calcareous bottoms ( Tommasi & Aron 1988; herein). Astropecten brasiliensis brasiliensis from Porto Belo-SC feed mostly on three mollusk species: the bivalves Corbula caribaea d’Orbigny, 1853 and Transenella stimpsoni Dall, 1902 , and the gastropod Natica pusilla Gould, 1841 . Patrizzi & Dobrovolski (2018) predicted that the habitable range of the Brazilian populations of A. brasiliensis may have a 7–16-fold expansion under higher atmospheric CO 2 concentrations. The effect of this expansion on the local communities is unknown, but it is likely to cause negative trophic impact ( Kordas et al. 2011).

Astropecten brasiliensis 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.

Neotype. NMNH E529 .

Type locality. São Sebastião Island, SP, Brazil.

Remarks. Although Clark & Downey (1992) mentioned that the neotype of A. brasiliensis has a vertical fringe of inferomarginal spines, we noticed that the neotype and the specimens from this study have an oblique fringe instead.

Because of its high phenotypic variability, five subspecies of A. brasiliensis were described, three of these not currently valid and synonymized with A. brasiliensis brasiliensis : Astropecten brasiliensis armatus ( Gray, 1840) , Astropecten brasiliensis erinaceus ( Gray, 1840) and Astropecten brasiliensis riensis Döderlein, 1917 . The other valid subspecies, Astropecten peruvianus Verrill, 1867 , was designated as a subspecies of A. brasiliensis by Döderlein (1917) without any explanation. We suspect that this change was made because H.L. Clark (1910) mentioned that A. peruvianus is very similar to Astropecten ( brasiliensis ) erinaceus.

With regards to A. armatus, Clark & Downey (1992) noted that A. brasiliensis and A. armatus are different species although there was much confusion in the past because of their morphological similarity. From the examination of the neotype of A. brasiliensis and of the figures of A. armatus presented by Fisher (1911, pl. 5, figs 1–2; pl. 51, fig. 3), we agree with Clark & Downey (1992) that these species are distinct based on the shape of the subambulacral spine. Both species have two spines in the first subambulacral row, with the distal spine being much larger than the proximal spine. In A. armatus , the distal spine is flattened, truncated and almost 3x larger than the proximal spine, while in A. brasiliensis the distal spine is blunt, cylindrical and 2x greater than the proximal spine; this pattern was also observed in the specimen from Bahia. Tortonese (1956) mentioned that A. brasiliensis has prominent flat spines in the proximal and distal regions of the inferomarginal plates (actinal view), while A. armatus only has prominent flat spines in the distal region of the inferomarginal plates. However, we noticed that the neotype of A. brasiliensis (R 87 mm) has flat spines as in A. armatus and the large specimen (R 103 mm) described from Bahia follows the pattern described by Tortonese (1956).

Figures

FIGURE 4. Specimen (R 103 mm) of Astropecten brasiliensis brasiliensis Müller & Troschel, 1842 (UFBA 132): (A–C) abactinal and (D–F) actinal view of body (A, C, D, F are in vivo); (G) madreporite; (H) interradial superomarginal spines; (I) superomarginal spines; (J) inferomarginal spines; (K) actinal view of inferomarginal plates; and (L) ambulacral furrow. Scale bars: A–B, D, E, 50 mm; C, F, K, 10 mm; G–I, L, 2 mm; J, 3 mm.

FIGURE 5. Specimen (R 21 mm) of Astropecten brasiliensis brasiliensis Müller & Troschel, 1842 (UFBA 40): (A) abactinal and (B) actinal view of body; (C) disc and superomarginal plates; (D) oral region; (E) ambulacral furrow; (F) interradial superomarginal spines; and (G) inferomarginal spines. Scale bars: A–B, 10 mm; C–D, F, 2 mm; E, G, 1 mm.