Thalamita quadrilobata Miers, 1884

Shaga, I Bevin, Priya, K, Ramar, Selvakumar, Srinidhi, S, Mohan, G Chandra, Ranganathan, Sukanya, Moulvi, S M M & Mani, Bhuvaneswari, 2023, A Small Collection of Subtidal Crabs (Crustacea: Decapoda: Brachyura) from the Palau Islands Collected by Dredging, Bulletin of the National Museum of Nature and Science. Series A, Zoology 49 (1), pp. 7-42 : 19-21

Thalamita quadrilobata Miers, 1884

( Fig. 7A–B )

Thalamita quadrilobata Miers, 1884, p. 539 , pl. 48 fig. B.─Alcock, 1899, p. 84.─ Stephenson and Hudson, 1957, p. 349, figs. 2G, 3G, pl. 4 fig. 4, pl. 8 fig. M, pl. 9 fig. F.─ Stephenson, 1972a, p. 151; 1972b, pp. 18 (in key), 51; 1976, p. 24.─Apel and Spiridonov, 1998, p. 260, figs. 77, 86.

Thalamita admeta var. intermedia Borradaile, 1903a, p. 203 (in key).

Thalamita Admete var. intermedia Borradaile : De Man, 1926, p. 203 (in discussion), fig. 2.

Thalamita borradailei Wee and Ng, 1995, p. 62 (in discussion).

Material examined. Inside of Gesodokkuru Reef off Arumonogui, Babelthuap I., Palau Is., dredged at ca. 20 m in depth; 1 ♀ (cb 10.8×cl 7.4 mm), NSMT-Cr 30974; July 13, 1980, K. Baba leg.

Remarks. De Man (1926) examined one of the syntypes of Thalamita admeta var. intermedia Borradaile, 1903 , to ascertain the taxonomic validity of his new species, Thalamita bilobata , and mentioned that both are different from each other most remarkably in the number of the teeth on the antennal basal segment. Wee and Ng (1995) discussed the taxonomic identity of some varieties of T. admete (Herbst, 1803) defined by Borradaile (1903a), and concluded that one of them, var. intermedia , is specifically distinct from T. admete . However, the corrected specific name, T. intermedia , was preoccupied by T. intermedia Miers, 1886 , and thus the new name, T. borradailei was proposed by Wee and Ng (1995). Later, Apel and Spiridonov (1998), who examined the syntypes of T. admeta var. intermedia and many specimens from the Indian Ocean and the West Pacific, concluded that T. borradailei falls into the size/age-related variation, accepting the tentative synonymisation of T. admete var. intermedia as proposed by Stephenson and Hudson (1957).

Thalamita quadrilobata is, otherwise, close to T. bilobata De Man, 1926 , with which T. miyakei Takeda, 1972 known by Takeda (1972) and Takeda and Hayashi (1973) was synonymized as shortly mentioned by Takeda (1989b). In T. quadrilobata , the front is two-lobed, each lobe is shallowly concave near the obtusely angulated lateral end, and the carapace anterolateral margin is armed with the remarkably sharp teeth, with a small fourth teeth ( Fig. 7A ). As clearly shown by De Man (1926: figs. 1a–b, 2), the antennal basal segment is armed with three spiniform teeth in T. quadrilobata , but only one in T. bilobata . Three sharp spines of the antennal basal segment are shown in the present paper (fig. 7B), and also seen in the line drawing given by Apel and Spiridonov (1998: fig. 77a–c).

Distribution. Widely distributed in the Indian Ocean, and also known from Indonesia, the Philippines, the Palau Islands, Australia, and French Polynesia in the Pacific, 5–25 m in depth.

Figures

Fig. 7. A–B: Thalamita quadrilobata Miers, ♀ (NSMT-Cr 30974; cb 10.8×cl 7.4mm). C–D: Thalamonyx gracilipes A. Milne-Edwards, ♂(NSMT-Cr 30976; cb 7.6×cl 5.9mm). E–F: Thalamita chaptalii (Audouin), ♂ (NSMT-Cr 30970; cb 12.6×cl 8.2mm) (E); ♂ (NSMT-Cr 30971; cb 8.6×cl 6.0mm) (F). G: Xiphonectes longispinosus (Dana) sensu Sakai (1939), ♂ (NSMT-Cr 30978; cb 17.6mm including epibranchial tubercles×cl 7.1 mm). H: Thalamita sexlobata Miers, ovig.♀ (NSMT-Cr 30975; cb 9.0×cl 6.3mm).