Thyrolambrus astroides Rathbun 1894

Thyrolambrus astroides Rathbun, 1894

(Fig. 26A–D)

Trindade specimens. 1 male (MZUSP 39694), cl 4.1 mm, cw 5.9 mm, Trindade Island, Ilha da Racha, 220°30’26.5”S, 29°20’48.0”W, J.B. Mendonça coll., 30.vii.2018, 24.8 m.

Comparative material examined. Thyrolambrus astroides: Brazil: Paraíba: 1 female (MZUSP 41176), R/V “Almirante Saldanha”, stn 1649, 7°26’S, 34°59’W, 6.x.1967, calcareous algae, 51 m. Pernambuco: 1 male (MZUSP 17192), Projeto RC (Recife), stn 156, 8°19’S, 34°38’W, calcareous algae, 61– 68 m. Bahia: 1 female (MZUSP 41234), Minerva Bank, 17°03.108’S, 37°37.216’W, J. Coltro coll., 12.viii.2012, 69 m. 1 female (MZUSP 17193), ibidem, stn 1981B, 12°59’S, 38°19’W, 27.ix.1968, calcareous algae, 59 m. Espírito Santo: 1 male (MZUSP 15393), Vitória – Trindade Seamount Chain, R /V “Astro Garoupa”, REVIZEE, stn 45C, 20°57’05”S, 33°00’20”W, near Dogaressa Bank, 9.xi. 1997, 125 m. 1 female (MZUSP 15394), Vitória–Trindade Seamount Chain, R/V “ Marion Dufresne ”, TAAF MD55/ Brésil Expedition, stn 14 DC27, 20°25’S, 36°42’W, Montague Bank, 14.v.1987, calcareous sand mixed with rocks, 81 m. Rio de Janeiro: 1 male (MZUSP 42514), Bacia de Campos, 23°05’13.420”S, 41°00’37.336”W, J.B. Mendonça coll., 25.i.2022, biogenic and muddy sediments, 100 m. 1 male (MZUSP 5530), Ilha Grande, R/V “Prof. W. Besnard”, stn 177, 26.vii.1966, 35 m.

Distribution. Gulf of Mexico, Cuba, Brazil (Pará to Rio de Janeiro) (Melo 2008; Felder et al. 2009). This is the first record of Thyrolambrus astroides from Trindade and the Vitória–Trintade Seamount Chain (Montague and Dogaressa banks).

Ecological notes. This species has been reported from white coral, loose rubble bottoms and biogenic and muddy sediments, between 24 and 370 m (Rathbun 1925; Felder et al. 2009; this study). The Trindade specimen was recovered from an artificial reef.

Remarks. In the Trindade minute specimen (cl 4.1 mm, cw 5.9 mm) (Fig. 26A), the frost-like reticulation of the carapace dorsal surface is still developing and is much weaker when compared to larger specimens (Fig. 26B–D).

Thyrolambrus astroides is a rather rare western Atlantic species. Its previous records from the eastern Pacific and Indo-West Pacific (Melo 1996; Felder et al. 2009) actually refer to T. verrucibrachium and T. efflorescens, respectively.