Celleporaria atlantica

Celleporaria atlantica (Busk, 1884)

( Figs 2G–H, 7D)

Cellepora mamillata var. atlantica Busk, 1884: 199, pl. 35, fig. 4;

Holoporella atlantica: Marcus, 1955: 310, figs 85–90;

Celleporaria albirostris: Ramalho, 2006: 162, fig. 38; Reis et al., 2016: supplementary table;

Celleporaria atlantica: Winston et al., 2014: 191, figs 33A–D, 34, 35; Almeida et al., 2015a: 4; Almeida et al., 2017: 296, figs 38–41; Bastos et al., 2018: table 1 (non

supplementary material fig. 1C).

Material examined. Abrolhos Bank, Bahia State, Brazil: MNRJ-Bry1340, Parcel dos Abrolhos, 4 m depth, February 2014, col. R. Moura, G. Amado-Filho & A. Bastos; MNRJ-Bry1355, Parcel dos Abrolhos, 15 m depth, February 2014, col. R. Moura, G. Amado-Filho & A. Bastos.

Description. Encrusting colonies, growing irregularly to form multiple layers by frontal budding; colony surface rough and thorny due to elongate suboral umbos; orange to light brown in colour with white umbos when alive (Fig. 7D); frontal wall smooth in young zooids and rough in older ones, imperforate except for some scattered tiny areolar pores (Fig. 2G, H). Primary orifice almost circular (104–113–119 µm long x 116–126–133 µm wide) with a smooth poster and with or without a very shallow sinus proximally; orifice frequently hidden by an elevated suboral umbo bearing an avicularium (Fig. 2G, H). Suboral avicularia located on umbos usually small with rostrum serrated, upwardly directed, sometimes enlarged, occupying almost the entire umbo (Fig. 2H); crossbar complete. Interzooidal avicularia of variable size (183–310–648 µm long), triangular or elongated, rounded distally; crossbar complete. Small (53–85 µm long), leaf-shaped avicularia present at the margins of some zooids, replacing an areolar pore, directed proximally, or randomly scattered (Fig. 2G). Ovicell hyperstomial, cap-shaped, not closed by the operculum of the maternal zooid.

Geographic distribution. Endemic to Brazil: Rio de Janeiro, Espírito Santo and Bahia states (Busk 1884; Marcus 1955; Ramalho 2006; Winston et al. 2014; Almeida et al. 2017; Bastos et al. 2018; present study).

Remarks. Celleporaria atlantica is very similar to C. albirostris (Smitt, 1873), described from the North Atlantic (Cape Hatteras to Florida, Caribbean and Gulf of Mexico), sharing with this species a suboral umbo containing a small avicularium at its tip. Nonetheless, C. albirostris has a subcircular orifice without condyles or sinus, and the peristome is undeveloped; at the tip of the suboral umbo there is an adventitious avicularium (not enlarged as in C. atlantica). Celleporaria albirostris lacks the leaf-shaped avicularia associated with the small marginal areolar pores of C. atlantica. Winston et al. (2014) described the lectotype (NHMUK 1887.12.9.769) of C. atlantica from Hassler’s material collected from Bahia State, while Busk (1884) and Marcus (1955) also described colonies from Bahia and Espírito Santo states, respectively. The Abrolhos specimens are very similar in the size and shape of the autozooids and avicularia, but differ by the absence of avicularia or narrow spines on the ooecial surface (see Marcus 1955, fig. 85). However, the lack of these structures on the ooecial surface is considered insufficient to erect a new species given the few ovicells observed in the Abrolhos sample.