Thranita coeruleipes (Hombron & Jacquinot, 1846)

Huang, Yu-Hsuan & Shih, Hsi-Te, 2021, Chthonius rhodochelatus Hadzi 1933, Zoological Studies 60 (60), pp. 1-45 : 31-33

Thranita coeruleipes (Hombron & Jacquinot, 1846) ( Figs. 4F , 18 )

Thalamita coeruleipes Hombron & Jacquinot, 1846: 53 , pl. 5(6–10) (type locality: Mangareva I., French Polynesia); Forest and Guinot 1961: 32 ( French Polynesia: Tahiti; Mangareva I. (lectotype )); Shen and Dai 1964: 61, 1 unnumb. fig. (upper) (Xisha Is.); Stephenson and Rees 1967: 64 ( French Polynesia; Samoa; E Australia; Mariana Is.; Philippines); Minei 1971: 64, pl. 3C ( Japan: Ryukyus); Sakai 1976: 371, pl. 132(2) ( Japan: Ryukyus); Cariaso and Garcia 1986: 219, fig. 30 ( Philippines); Dai et al. 1986: 227, fig. 135(1), pl. 30(6) (Xisha Is.); Dai and Yang 1991: 247, fig. 135(1), pl. 30(5) (Xisha Is.); Ng et al. 2008: 154 (list); Yang et al. 2008: 790 (list; Nansha Is.; Xisha Is.); Yang et al. 2012: 265, fig. 98, pl. 11(5) (Nansha Is.; Xisha Is.).

Thalamita spinimana – Huang and Yu 1997: 148, 1 unnumb. fig. ( Taiwan: Keelung: Heping I.; Pingtung: Siaoliouciou and Wanlitong); Chen and Lo 2014: 85, 3 unnumb. figs. ( Taiwan: Pingtung: Siaoliouciou). (not Thalamita spinimana Dana, 1852 ).

Thranita coeruleipes – Evans 2018: 4, fig. 2I ( Samoa); Sasaki 2019: 9282 (list).

Thranita cf. coeruleipes – Shih et al. 2020b: 36 ( Taiwan: Dongsha I.).

Material examined: Taiwan: 1 male (59.7 × 40.5 mm) (NCHUZOOL 16507), Wanlitong, Kenting, Pingtung (21°59'43.0"N 120°42'19.4"E), coll. YH Huang et al., 10 Apr. 2020; 1 male (48.5 × 33.4 mm) (NCHUZOOL 16512), shallow subtidal zone in Bitou Fishing Port, Kenting, Pingtung (21°54'17.4"N 120°50'55.5"E), coll. YH Huang et al., 8 Apr. 2020; 1 ovig. female (57.3 × 38.9 mm) (NCHUZOOL 16513), Cichihmen, Dongyupingyu, Penghu (23°15'21.1"N 119°30'47.2"E), coll. YH Huang et al., 9 May 2020; 1 female (35.8 × 25.0 mm) (NCHUZOOL 16514), Cichihmen, Dongyupingyu, Penghu (23°15'20.3"N 119°30'51.9"E), coll. YH Huang et al., 10 May 2020; 1 male (26.0 × 18.3 mm), 1 female (28.9 × 19.9 mm) (NCHUZOOL 16515), Sihzihjiao, Dongyupingyu, Penghu (23°15'19.3"N 119°30'38.3"E), coll. YH Huang et al., 11 May 2020; 1 male (40.4 × 27.4 mm) (NCHUZOOL 16516), Dongsha I. (20°42'4.5"N 116 ° 43 ' 5.9 "E), 20 Jul. 2012; 1 male (41.4 × 28.0 mm) (NCHUZOOL 16517), Dongyupingyu, Penghu (23°15'22.2"N 119°30'40.8"E), coll. YH Huang et al., 10 May 2020; 2 males (36.7–37.2 × 25.2–25.3 mm) (NCHUZOOL 16518), Dongyupingyu, Penghu (23°15'27.0"N 119°30'46.2"E), coll. YH Huang et al., 1 Aug. 2020; 1 male (38.4 × 26.4 mm) (NCHUZOOL 16519), Dongjiyu, Penghu (23°15'12.2"N 119°40'3.7"E), coll. YH Huang et al., 2 Aug. 2020; 1 male (46.1 × 31.8 mm) (NCHUZOOL 16524), Wanlitong, Kenting, Pingtung, coll. HT Hung, 13 Feb. 2003; 1 male (46.5 × 31.2 mm), 1 ovig. female (40.0 × 28.3 mm) (NCHUZOOL 16525), Dongsha I. (20°41'53.6"N 116°43'29.8"E), coll. YH Huang and K Chang, 6 Nov. 2019; 1 male (11.9 × 8.4 mm) (NCHUZOOL 16592), Dongsha I. (20°42'21.6"N 116°42'39.0"E), coll. YH Huang and K Chang, 5 Nov. 2019.

Diagnosis: Carapace subhexagonal, 1.4–1.5 times broader than long, with broadest between anterolateral tooth 3, surface densely pilose. Frontal, protogastric and epibranchial regions each with a pair of ridges; mesogastric and metagastric ridges unbroken; mesobranchial and cardiac ridges absent ( Fig. 18A ). Front with 6 lobes. Supraorbital margins with 2 notches, inner lobe arched ( Fig. 18A ). Inner infraorbital lobes ending in spine. Anterolateral margins with 5 teeth, last 2 subequal, smaller than first 3 teeth ( Fig. 18A ). Basal antennal segment with 2–3 sharp spines. Chelipeds slightly unequal, with surface granulated, merus with 3 sharp spines on inner margin, a spinule each on distal end of dorsal and ventral surfaces near articulation of carpus; carpus with 1 strong spine on inner margin, 3 spines on outer margin; palm with 5 sharp spines on dorsal surface, outer surface with 3 granulated ridges, inner surface with 1 ridge. P5 with merus having strong spine on inner margin, distal end with small spine; propodus with inner margin serrated. G1 stout, with distal part gradually curved ( Fig. 18B–E ).

Coloration: Carapace with brown and white stripes; chelipeds with orange and yellow granules; ambulatory legs brownish green with white stripes, dactylus orange with white stripes ( Fig. 4F ).

Distribution: Hawaii (suspect, see Castro 2011); French Polynesia; Samoa; Fiji; Australia; New Guinea; Indonesia; Guam; Palau; Philippines; Nansha Is.; Taiwan (incl. Dongsha I.; Fig. 1 : no. 17); Japan (Ryukyus); Xisha Is.; India; Madagascar; Mauritius ( Huang and Yu 1997; Chen and Lo 2014; Sasaki 2019; this study).

Ecological notes: This species inhabits the shallow subtidal zones in coral reefs and seagrass beds. Juveniles were often found on seagrass beds.

Remarks: In the genus Thranita Evans, 2018 , there are six species having spines on basal antennal segment, viz. Thr. cerasma ( Wee & Ng, 1995) , Thr. coeruleipes (Hombron & Jacquinot, 1846) , Thr. pelsarti ( Montgomery, 1931) , Thr. pseudopelsarti (Crosnier, 2002) , Thr. rubridens ( Apel & Spiridonov, 1998) and Thr. spinimana ( Dana, 1852) (Hombron and Jacquinot 1846; Wee and Ng 1995; Apel and Spiridonov 1998; Crosnier 2002). Among them, Thr. spinimana and Thr. pelsarti were reported previously from Taiwan ( Ng et al. 2017); and Thr. cerasma and Thr. coeruleipes are added in this study.

Thranita coeruleipes has been sometimes misidentified under the name “ Thr. spinimana ” in Taiwan (e.g., Huang and Yu 1997; Chen and Lo 2014). They can be distinguished by the following characters: (1) chelipedal carpus with granules on dorsal surface in Thr. coeruleipes ( Fig. 4F ; Hombron and Jacquinot 1846: pl. 5(6)) (vs. armed with 2–3 spines in Thr. spinimana ; Wee and Ng 1995: fig. 67D; Yang et al. 2012: fig. 129b); (2) palm with 5 spines on dorsal surface in Thr. coeruleipes (Hombron and Jacquinot 1846: pl. 5(6); Yang et al. 2012: fig. 98d) (vs. 7–9 spines in Thr. spinimana ; Dana 1852: pl. 17(8b); Wee and Ng 1995: fig. 67D; Yang et al. 2012: fig. 129b); (3) G1 stout, distal part bent laterally in Thr. coeruleipes ( Fig. 18B–E ; Dai et al. 1986: fig. 135(1); Yang et al. 2012: fig. 98g) (vs. slender, slightly bent laterally in Thr. spinimana ; Dai et al. 1986: fig. 135(2); Wee and Ng 1995: fig. 67K– M; Yang et al. 2012: fig. 129f).

Thranita coeruleipes can be distinguished from Thr. pelsarti by the following characters: (1) anterolateral teeth 4 and 5 subequal in Thr. coeruleipes ( Fig. 18A ; Hombron and Jacquinot 1846: pl. 5(6)) (vs. tooth 4 smaller than tooth 5 in Thr. pelsarti ( Fig. 22A ; Montgomery 1931: pl. 28(3)); (2) front lobes blunt in Thr. coeruleipes ( Fig. 18A ; Hombron and Jacquinot 1846: pl. 5(6)) (vs. straight in Thr. pelsarti ; Fig. 22C ; Montgomery 1931: pl. 28(3)).

Figures

Fig. 4. Species of the family Portunidae. A, Thalamita gatavakensis Nobili, 1906, male (16.5 × 9.3 mm) (NTOU), Mao-ao, New Taipei City; B, Thalamita spinifera Borradaile, 1902, female (12.6 × 9.0 mm) (NCHUZOOL 16531), Erzihliao Fishing Port, Kaohsiung; C, Thalamitoides quadridens A. Milne-Edwards, 1869, male (25.4 × 13.3 mm) (NTOU), Sansiantai, Taitung; D, Thalamitoides tridens A. Milne-Edwards, 1869, female (16.1 × 8.2 mm) (NCHUZOOL 16520), Dongsha I.; E, Thranita cerasma (Wee & Ng, 1995), female (66.4 × 42.6 mm) (NCHUZOOL 16537), Dongsha I.; F, Thranita coeruleipes (Hombron & Jacquinot, 1846), male (59.7 × 40.5 mm) (NCHUZOOL 16507), Wanlitong, Kenting, Pingtung.

Fig. 18. Thranita coeruleipes (Hombron & Jacquinot, 1846), male (46.5 × 31.2 mm) (NCHUZOOL 16525). A, carapace; B–E, right G1; B, C, dorsal view; D, E, ventral view.

Fig. 1. Taiwan main island and adjacent islets, with the collection localities shown in gray circles (see Table 1).

Fig. 22. Thranita pelsarti (Montgomery, 1931), male (43.6 × 27.5 mm) (NCHUZOOL 16568). A, carapace; B, basal antennal segment; C, frontal lobes; D–G, right G1; D, E, dorsal view; F, G, ventral view.