Echinaster (Othilia) brasiliensis Mueller & Troschel, 1842

Gondim, Anne Isabelley, Christoffersen, Martin Lindsey & Pereira Dias, Thelma Lucia, 2014, Taxonomic guide and historical review of starfishes in northeastern Brazil (Echinodermata, Asteroidea), ZooKeys 449, pp. 1-56 : 15-16

Echinaster (Othilia) brasiliensis Mueller & Troschel, 1842 Figure 11a-e

Echinaster brasiliensis Müller & Troschel, 1842: 22. Tommasi 1958: 22-23, pl. 4, fig. 3; 1970: 17, figs 44-45. Brito 1962: 3; 1968: 13-14, pl. 6, fig. 6. Carrera-Rodriguez and Tommasi 1977: 103-104. Tommasi and Aron 1987: 3. Tommasi et al. 1988: 6. Ávila-Pires 1983: 440-442, figs 8-9. Fernandes et al. 2002: 422. Netto 2006: 30-32, pl. 5a. Alves et al. 2010: 758. Miranda et al. 2012: 144.

Echinaster braziliensis Verrill, 1915: 41-42, pl. 26, fig. 1.

Echinaster antonioensis Bernasconi, 1955: 72-73, pl. 6, figs 1-2. Tommasi 1958: 22, pl. 4, fig. 2. Brito 1968: 15.

Echinaster sentus Bernasconi, 1956: 136-137, pl. 4, fig. 3. Tommasi 1958: 23-24, pl. 4, fig. 4; 1970: 17-18, fig. 46 a 48. Brito 1968: 14, pl. 6, figs 3-4.

Echinaster spinulosus Bernasconi, 1956: 138-139, pl. 4, fig.4. Tommasi 1958: 21-22, pl. 4, fig. 1. Brito 1968: 14, pl. 6, fig. 1-2.

Echinaster densispinulosus Tommasi, 1970: 18-19, figs 49-51.

Echinaster nudus Tommasi, 1970: 18-19, figs 52-54. Gondim et al. 2008: 154.

Echinaster (Othilia) brasiliensis Clark & Downey, 1992: 21-22, pl. 4a. Hopkins et al. 2003: 98-100. Machado et al. 2008: 182-183. Lima and Fernandes 2009: 59. Xavier 2010: 75.

Material examined.

Rio Grande do Norte: Macau, Diogo Lopes, 1spec., UFPB/ECH.869, 09.XI.2007, 1spec., UFPB/ECH.872, 09.XI.2008, 1spec., UFPB/ECH.1426, 09.XI.2007. Paraíba: 7°01'02"S; 34°47'55"W, 1spec., UFPB/ECH.571, 03.VI.2003; 7°03'50"S; 34°47'19"W, 1spec., UFPB/ECH.569, 21.III.2006; Cabedelo, Farol de Cabedelo reef, 1spec., UFPB/ECH.729, 26.X.1980; Cabedelo, Areia Vermelha reef, 1spec., UFPB/ECH.1465, 22.II.2008; João Pessoa, Cabo Branco Beach, 2spec., UFPB/ECH.138, 04.XI.2006; João Pessoa, Seixas reef, 1spec., UFPB/ECH.1183, 22.XII.2007. Bahia: Santo Amaro, Cabuçu Beach, 3spec., UFPB/ECH.718, 19.IX.1987.

Type-locality.

Ubatuta, São Paulo, Brazil ( Walenkamp 1976).

Description.

Disk small (Fig. 11a). Body concave on abactinal surface, plane on actinal surface. Five long-narrow to short-thick arms (usually decreasing rapidly in thickness towards tips) (Fig. 11a, b). Abactinal figs flattened or slightly mammiform (Fig. 11e), forming a reticulum and bearing a short, conical spine (Fig. 11c). Abactinal figs separated by small, elongated, secondary figs. Anus normally placed within the central pentagon of the disk and surrounded by 4-6 spines. Madreporite circular, with numerous small granules and irregular sulci. Superomarginal figs more granulose than inferomarginal figs. Papular areas more numerous on dorsal and lateral regions of arms (Fig. 11c). Adambulacral figs with three spines, the inner one being rudimentary (Fig. 11d). The two outer spines are subequal and larger than the remaining spine.

Colour. Quite variable, being light brown, reddish-brown, dark red or even yellowish red ( Gray et al. 1968; Benavides-Serrato et al. 2011).

Distribution.

Florida, Cuba, Honduras, Panama, Colombia, Brazil, and Argentina ( Tommasi 1958, Alvarado et al. 2008, Benavides-Serrato et al. 2011). In Brazil: PB, PE, AL, BA, ES, SP, RJ, SC, and RS ( Verrill 1915, Tommasi 1958, Carrera-Rodriguez and Tommasi 1977, Fernandes et al. 2002, Magalhães et al. 2005, Gondim et al. 2008, Xavier 2010, Miranda et al. 2012). This paper provides the first record for the State of Rio Grande do Norte. From 1 to 360 m in depth ( Benavides-Serrato et al. 2011).

Remarks.

Many characters of Echinaster (Othilia) brasiliensis and other species of the genus present great plasticity, with the consequence that the taxonomy of the genus cannot be considered well resolved. Echinaster (Othilia) brasiliensis differs from Echinaster (Othilia) echinophorus for presenting a larger number of rows of dorsal longitudinal spines (9-15) and actinal figs not mammiform. Echinaster (Othilia) sentus differs for having more numerous and shorter dorsal spines and for having mammiform abactinal figs. Walenkamp (1976) pointed out some variations observed in specimens from Suriname, such as: number of adambulacral spines (from 2 to 5), number of spines per dorsal longitudinal row (from 1 to 15), and size of the dorsal papular areas. In our study, as well as the large plasticity in the number of dorsal longitudinal spines (from 7 to 13), a character used as diagnotic for the genus, the number of spines surrounding the anus and the shape of the arms also proved to be quite variable. However, these morphological variations do not seem to be related to ontogenetic stages. Despite both adults and juveniles being present in our material, these variations occurred among specimens of a same size class. According to Machado et al. (2008), the most common shape of Echinaster (Othilia) brasiliensis presents narrow and elongate arms, while a smaller proportion of individuals have short and thick arms and less numerous spines. Tommasi (1970) synonymized Echinaster (Othilia) antonioensis De Loriol, 1904 with Echinaster (Othilia) brasiliensis , though without providing further details. According to him (Tommasi op. cit.) the characters used by De Loriol to distinguish the two species are all dependent on fixation mode or represent highly variable characters. An excelent discussion on the synonyms of the several species of Echinaster (Othilia) brasiliensis is found in Clark and Downey (1992). Avila-Pires (1983) proposed the presence of only two species of Echinaster for the Brazilian littoral, Echinaster (Othilia) echinophorus being restricted to the northeastern coast and Echinaster (Othilia) brasiliensis to the south and southeastern coast. We disagree with this opinion, suggesting that Echinaster (Othilia) brasiliensis also occurs in northeastern Brazil. More taxonomic studies are clearly needed in order to better establish the interspecific limits between these two species.

Ecological notes.

This species lives in sand, substrates of sand with mud, and consolidated substrates, often associated with the bivalves Mytillus sp. and Lithophaga sp. ( Penchaszadeh 1973), having also been observed in banks of Thalassia sp. ( Benavides-Serrato et al. 2011). Echinaster (Othilia) brasiliensis is frequently found in intertidal regions or shallow waters, and may be strongly influenced by water salinity ( Machado et al. 2008). In this study, the species was found mainly in reef environments and hypersaline mangrove areas, always together with Echinaster (Othilia) echinophorus . According to Machado et al. (2008), this species is common along the coast of Rio de Janeiro, being intensively collected by aquarists without futher control on their extraction and commercialization. Alves and Dias (2010) recorded its use for medical purposes (treatment of asthma). Echinaster (Othilia) brasiliensis is listed among the species vulnerable to extinction ( Machado et al. 2008).