Xiphonectes A. Milne-Edwards, 1873

Huang, Yu-Hsuan & Shih, Hsi-Te, 2021, Chthonius rhodochelatus Hadzi 1933, Zoological Studies 60 (60), pp. 1-45 : 21

Genus Xiphonectes A. Milne-Edwards, 1873 Xiphonectes tuberculosus (A. Milne-Edwards, 1861)

( Figs. 3H , 12 )

Neptunus tuberculosus A. Milne-Edwards, 1861: 333 , pl. 31(5) (type locality: Hawaii).

Neptunus (Hellenus) tuberculosus – Shen 1940: 220 ( Hong Kong).

Portunus tuberculosus – Stephenson and Rees 1967: 52, fig. 18, pl. 6B ( Palau; Philippines; China); Moosa 1981: 147 ( Philippines); Dai et al. 1986: 199, fig. 116(3), pl. 26(6) ( China, incl. Hainan I.); Dai and Yang 1991: 218, fig. 116(3), pl. 26(6) ( China, incl. Hainan I.); Dai and Xu 1991: 23, fig. 18 (Nansha Is.); Yang et al. 2008: 788 (list).

Portunus (Xiphonectes) tuberculosus – Ng et al. 2008: 153 (list).

Xiphonectes tuberculosus – Sasaki 2019: 9130 (list).

not Portunus tuberculosus – Chou et al. 1999: 30 ( Taiwan: Kaohsiung). (= Neptunus trituberculatus Miers, 1876 ).

Material examined: Taiwan: 3 males (20.3–26.9 × 12.0– 15.8 mm), 2 females (23.2–23.5 × 13.2–13.7 mm) (NCHUZOOL 16530), Zuoying, Kaohsiung, Jun. 2001; 1 male (26.4 × 16.4 mm) (NCHUZOOL 16532), Dalinpu, Siaogang, Kaohsiung, 12 May 1997; 1 female (20.7 × 11.9 mm) (NCHUZOOL 16559), Erzihliao Fishing Port, Kaohsiung, coll. YH Huang, 8 Jul. 2018; 1 male (25.1 × 14.7 mm), 1 ovig. female (26.8 × 15.9 mm) (NCHUZOOL 16594), Dalinpu, Siaogang, Kaohsiung, Jun. 2001.

Diagnosis: Carapace transversely hexagonal, 1.7 times broader than long, surface densely pilose, with granular patches. All carapace ridges absent, except epibranchial regions with a pair of granulated ridges ( Fig. 12A ). Front with 4 rounded teeth, median 2 smaller and more protruding than lateral ( Fig. 12A ). Supraorbital margins with 2 notches, inner supraorbital angle tooth-like, with ventromesial ledge. Anterolateral margins with 9 teeth, tooth 9 largest ( Fig. 12A ). Junction between posterolateral and posterior margins tooth-like ( Fig. 12A ). Basal antennal segment with a lateral blunt lobe entering orbital cavity. Chelipeds granulated and pilose, merus with 3 blunt spines on inner margin, outer margin with 1 spine; carpus with spine each on inner and outer margins; palm with 2 granulated ridges and 1 spine on dorsal surface, outer surface with 3 ridges. P5 with merus granulated on inner margin. Maxillipeds 3 with merus longer than broad, anteroexternal angle strongly expanding to a prominent auriculiform structure. Male pleon with pleomere 6 trapezoidal, longer than broad. G1 smooth, distal half slender and bent laterally ( Fig. 12B–E ).

Distribution: Hawaii; Australia; Indonesia (Makassar); Guam; Palau; Philippines; Nansha Is.; Taiwan; Japan (incl. Ryukyus); China (incl. Hong Kong; Hainan I.); Vietnam; Thailand; India; Sri Lanka; Maldives; Gulf of Aden; Gulf of Oman; Seychelles; Tanzania; Madagascar ( Sasaki 2019; this study).

Ecological notes: Specimens were collected by trawling at about 30 meters deep (this study).

Remarks: Chou et al. (1999) recorded the name “ Portunus tuberculosus ” from Taiwan, but Ng et al. (2001 2017) considered it should be a typographical mistake of Portunus trituberculatus . As a result, Xiphonectes tuberculosus is the first confirmed record from Taiwan in our study.

Figures

Fig. 3. Species of the family Portunidae. A, Carupa ohashii Takeda, 1993, female (34.9 × 23.1 mm) (NCHUZOOL 16500), Dongsha I.; B, Lupocycloporus minutus (Shen, 1937), male (17.5 × 9.7 mm) (NCHUZOOL 16534), Zuoying, Kaohsiung; C, Lupocyclus inaequalis (Walker, 1887), male (21.6 × 16.3 mm) (NCHUZOOL 16551), Erzihliao Fishing Port, Kaohsiung; D, Lupocyclus tugelae Barnard, 1950, male (17.5 × 13.1 mm) (NCHUZOOL 16560), Erzihliao Fishing Port, Kaohsiung; E, Podophthalmus minabensis Sakai, 1961, male (25.2 × 14.9 mm) (NCHUZOOL 16499), Dalinpu, Siaogang, Kaohsiung; F, Monomia gladiator (Fabricius, 1798), male (53.0 × 31.2 mm) (NCHUZOOL 16506), Erzihliao Fishing Port, Kaohsiung; G, Monomia lucida Koch & Ďuriš, 2018, male (54.8 × 30.7 mm) (NCHUZOOL 16538), Erzihliao Fishing Port, Kaohsiung; H, Xiphonectes tuberculosus (A. Milne-Edwards, 1861), males (24.3 × 14.3 mm) (NCHUZOOL 16530), Zuoying, Kaohsiung.

Fig. 12. Xiphonectes tuberculosus (A. Milne-Edwards, 1861). A, carapace, male (26.9 × 15.8 mm); B–E, male (24.3 × 14.3 mm) (NCHUZOOL 16530), right G1; B, C, dorsal view; D, E, ventral view.