Paraleptuca crassipes (White, 1847)

Michie, Laura A., Barnes, R. S. K., Clark, Paul F., Bennett, Wayne A. & Cragg, Simon M., 2021, Distinguishing ten sympatric species of fiddler crab (Decapoda: Ocypodidae) using a suite of phenotypic characteristics, Zootaxa 5026 (4), pp. 480-506 : 493-496

Paraleptuca crassipes (White, 1847)

( Figure 9a–j )

Material examined. 10 ♀, 10 ♂, Kaledupa , Indonesia, 5º 29’ 50’’S, 123º 45’ 20’’E, mud flat in front of mangroves, coll. L. Michie, 26.08.2014 . 10 ♀, 10 ♂, Kaledupa , Indonesia, 5º 29’ 51’’S, 123º 45’ 20’’E, on the mangrove perimeter, coll. L. Michie, 29.08.2014 .

Diagnosis. Carapace: broader than long; smooth; front broad; anterolateral angles marginally acute; anterolateral margins short; dorsolateral margins distinct. Major cheliped: manus similar length to dactyl and pollex; outer manus with small round, almost triangular, depression near pollex base.

Colouration ( Figure 9a–d ). Colour variation is one of highest at this site, but that of major cheliped remains constant.

Adult male. Carapace: generally red, sometimes with black or blue markings and occasionally all black with blue and red markings, anterior ventral surface often black, sometimes red. Third maxilliped: normally blue. Major cheliped: dactyl and pollex pale pink/red, manus pink/red and remainder red. Minor cheliped & ambulatory legs: generally black or red.

Adult female. Carapace: varies greatly, sometimes entirely red, often red with blue and white markings, can be black with white/blue transverse markings. Ambulatory legs: similar to those of males.

Juvenile male. Carapace: similar to adults, usually red or black, often has white and blue markings. Major cheliped: light brown or pink and, becoming darker with maturation.

Juvenile female. Similar colour patterns to juvenile males.

Gonopod morphology ( Figure 9e–h ). G1 strongly curved in dorso-lateral direction; distal end long, strongly curved in lateral direction, tapers before bulging slightly at tip, termination rounded; margins folded causing a twisting longitudinal groove visible on posterior surface; pore of sperm channel in midline; distal protuberance short.

Gastric mill ( Figure 9i, j ). Urocardiac ossicles moderately complex, with 6 transverse ridges of median teeth, different in shape, 1 and 2 strongly arched, 1–4 decreasing in size distally, 5 and 6 are sometimes fused and appear almost as one; stem region has just 1 pair of cusps. Lateral tooth plate with 22 comb-shaped teeth.

Biology. Paraleptuca crassipes is a relatively small-size species (largest male CL = 10.5 mm, CB = 16.2 mm, largest female CL = 11.3 mm, CB = 17.1 mm); one of most abundant species on shore, present in mid and high intertidal zones, often in mangroves and under stilted houses.

Distribution. China, Japan, Philippines, Thailand, Indonesia, Papua New Guinea, Melanesia, Micronesia.

Remarks. Paraleptuca crassipes can be distinguished by the strong curve of the G1, the depression on the manus of the major cheliped and the striking red colouration. The specimens examined compare well with the original description, but this is the first description of the gastric mill for P. crassipes and the moderately complex morphology is similar to that of A. perplexa .

Figures

FIGURE 9. Paraleptuca crassipes (White, 1847): a–d Sulawesi Tenggara, Indonesia. Adult male colouration; a, large chela; b, carapace dorsal view. Adult female colouration; c, frontal view; d, carapace dorsal view. Photos credit L. Michie. Line drawing of right G1; e, mesial view; f, lateral view; CLSM images of apical part G1; g, mesial view; h, lateral view; SEM images of male gastric mill; i, median tooth plate, ventral view; j, left lateral tooth plate, mesial view.