Tubuca coarctata (H. Milne Edwards, 1852 )

Jimenez, Pedro Julião, Chang, Kai, Shih, Hsi-Te & Yasuhara, Moriaki, 2024, Confirming the occurrence of two fiddler crabs, Tubuca dussumieri (H. Milne Edwards, 1852) and T. coarctata (H. Milne Edwards, 1852) (Crustacea: Decapoda: Ocypodidae), in Hong Kong by DNA barcoding and morphology, Zootaxa 5476 (1), pp. 177-191 : 182

Tubuca coarctata (H. Milne Edwards, 1852)

( Figs. 3A, B , 4A, B , 5 )

Material examined. 1 male (CW 19.5 × CL 11.9 mm), NCHUZOOL 17189, Tai Tam Bay (22.24665°N, 114.22510°E), Hong Kong, coll. P. J. Jimenez, 29 Jun. 2022 .

Remarks. Tubuca coarctata is widely distributed in the West Pacific, from Indonesia (including Sumatra) to the Ryukyus and Fiji ( Crane 1975; Shih et al. 2015). The type locality is listed as “ Odessa ” (H. Milne Edwards 1852: 156), which likely to be an error as the only familiar locality by that name is the port city of Odessa in Ukraine and, as such, the actual type locality is unknown (viz. Crane 1975). The male specimen collected from Hong Kong has the following important characters: carapace strongly trapezoid in outline, anterolateral angle acute, directed anterolaterally, anterolateral margin very short, dorsolateral margin moderately long ( Fig. 5A ); major cheliped with both outer dactylus and outer pollex with 1 groove ( Fig. 5B ); G1 moderately long, slightly tapering distally; thumb extending beyond base of tube; pore wide, at end of a short chitinous tube, flanges absent; inner process spinous, close to tubular end of shaft ( Fig. 5C–F ); fresh-preserved color on anterior carapace pale and dark on posterior, cheliped orange ( Figs. 3A, B , 4A, B ). The above characters agree with specimens of T. coarctata from Taiwan ( Shih et al. 2015) and can be confirmed as T. coarctata by morphology. The COI analysis also supports the species identity ( Fig. 7A ; see DNA analysis). This is a new record to the fiddler crab fauna of Hong Kong.

Figures

FIGURE 3. Color in life, Tai Tam Bay, Hong Kong SAR:(A, B) male Tubuca coarctata (H. Milne Edwards, 1852), NCHUZOOL 17189; (C–E) male and (F–H) female T. dussumieri (H. Milne Edwards, 1852). Specimens not collected.

FIGURE 4. Male specimen (A, B) of Tubuca coarctata (H. Milne Edwards, 1852) (19.5 × 11.9 mm; NCHUZOOL 17189); male (C, D) (21.9 × 13.5 mm; NCHUZOOL 17191) and female specimens (E, F) (21.6 × 14.2 mm; NCHUZOOL 17190) of T. dussumieri (H. Milne Edwards, 1852). (A, C, E) dorsal view; (B, D, F) ventral view. Scale bar = 10 mm.

FIGURE 5. Tubuca coarctata (H. Milne Edwards, 1852), male (19.5 × 11.9 mm), NCHUZOOL 17189, Tai Tam Bay, Hong Kong, NCHUZOOL 17189: (A) carapace; (B) major cheliped; (C) right G1 mesial view; (D) right G1 mesial view of distal part; (E) right G1 lateral view; (F) right G1 lateral view of distal part.

FIGURE 7. Genealogical network for the COI haplotypes observed within the clades of Tubuca coarctata (H. Milne Edwards, 1852) (A), and T. dussumieri (H. Milne Edwards, 1852) (B). Unlabelled hatches indicate inferred haplotypes not found in the sampled population. Gray circle indicates the haplotype found in Hong Kong. For haplotype names, see Table 1. AU:Australia; FJ: Fiji, HK: Hong Kong; ID: Indonesia; ML: Malaysia; PH: Philippines; RK: Ryukyus; TW: Taiwan.