Thandarum manoelina (Tommasi 1971) comb. nov.

(Figures 5–6)

Cucumaria manoelina Tommasi 1971: 2, figs. 3–7.

Cucumaria pulcherrima — Tommasi 1969: 141, pl. 11, fig. 13.

Type material. Neotype: designated herein, Guarajuba, Camaçari, BA, Brazil (12°47’ S; 38°08’ W): 23 m, 1 July 2007, 1 spm 0.5 cm long (UFBA 1746). [Holotype originally at the Tommasi collection at the Universidade de São Paulo; type locality: Ilha Grande – RJ, Brazil, now lost].

Other material examined. Guarajuba, Camaçari, BA, Brazil (12°47’ S; 38°08’ W): 23 m, 1 July 2007, 1 spm 0.5 cm long (UFBA 01844); 23 m, 15 August 2010, 15 spms 0.3–0.7 cm long (UFBA 1747); 23 m, 15 July 2011, 2 spms 0.5 cm long (UFBA 1748). Baía de Todos-os-Santos, Salvador, BA, Brazil (12°50’ S; 38°45’ W): 12 m, 9 March 2010, 1 spm 3 cm long (UFBA 1749).

Neotype diagnosis: Body U-shaped; tube feet arranged in two rows restricted to the ambulacral region. Ten tentacles, ventral-most pair smaller. Calcareous ring compact; radial and interradial plates joined only at their base; radials with posterior processes subdivided. Deposits: body wall with four-pillared tables and irregular buttons; introvert with rosettes; tentacles with rods; and tube feet with rods and star-shaped endplate.

Neotype description. Body U-shaped (Fig. 5 A). Tube feet arranged in double rows restricted to the ambulacra. Ten tentacles, ventral-most pair smaller. Anal region with five groups of three papillae. Calcareous ring compact and delicate, radial and interradials united only at their base (Fig. 5 B). Radials thin anteriorly and thick at the base, with thick and subdivided posterior processes (made up of 3–4 pieces) (Fig. 5 C). Interradials triangularshaped and strongly concave. Radial/interradial length ratio approximately 1:3. The internal morphology of the specimens could not be observed but, according to Tommasi (1971), this species bears one Polian vesicle. Body color yellowish in vivo and white in ethanol.

Deposits: body wall with four-pillared tables (30–60 µm) and buttons (70–120 µm). Table discs with irregular and smooth margins, and a strong central concavity bordered by numerous irregular perforations; spire high and ending in many teeth (± 20) (Fig. 6 A–C). Buttons with irregular shape and many perforations (Fig. 6 D–E). Introvert with rosettes (20–50 µm). Tentacles with typical rods (70–90 µm) (Fig. 6 F). Tube feet with typical rods (80–100 µm) (Fig. 6 G) and a star-shaped endplate entirely perforated (100–120 µm) (Fig. 6 H).

Distribution. Brazil (Bahia and Rio de Janeiro); depth: 12–50 m (Tommasi 1971; present paper).

Biological notes. This species has been found buried in silt, sand (Tommasi 1971), medium sand and gravel (present paper).

Remarks. The genus Cucumaria belongs to the family Cucumariidae and, therefore, has a simple calcareous ring, lacking posterior processes. The holotype of Cucumaria manoelina was originally described by Tommasi (1971) as possessing a calcareous ring with posterior processes, a typical ring of the Sclerodactylidae or Phyllophoridae . The morphology of the calcareous ring indicates that C. manoelina should be classified in the subfamily Sclerothyoninae (family Sclerodactylidae) since the radials are compact (i.e. without subdivisions), radials and interradials are united only at their base, and the radials are 3–4 times larger than the interradials. Three Sclerothyoninae genera have been described; among them, the diagnosis of the genus Thandarum includes the species C. manoelina . In this regard, we propose the new combination Thandarum manoelina (Tommasi 1971) .

Thandarum was recently described to the coast of Argentina (Buenos Aires, Martinez & Brogger 2012) and T. manoelina extends the distribution of this genus to the tropical Brazilian waters (up to Bahia State). Thandarum manoelina differs from Thandarum hernandezi Martinez & Brogger 2012 by the presence of smaller tables (40–60 µm vs. 260 µm—same-sized spms) with irregular discs (vs. circular margins) and numerous perforations (vs. few perforations). Thandarum manoelina differs from the other Sclerothyoninae ( Sclerothyone velligera [Ludwig & Heding 1935], Sclerothyone unicolumnus Thandar 2008 and Temparena chuni [Ludwig & Heding 1935]—all from South Africa) by the presence of four-pillared body wall tables and rosettes in the introvert.

Thandarum manoelina is the first occurrence of the subfamily Sclerothyoninae in the Brazilian coast.