Pachygrapsus crassipes Randall, 1840

Poupin, Joseph, Davie, Peter J. F. & Cexus, Jean-Christophe, 2005, A revision of the genus Pachygrapsus Randall, 1840 (Crustacea: Decapoda: Brachyura, Grapsidae), with special reference to the Southwest Pacific species, Zootaxa 1015 (1), pp. 1-66 : 9-12

Pachygrapsus crassipes Randall, 1840 ( Figures 2a–e , 14g , 15g , 16 )

Pachygrapsus crassipes Randall, 1840: 127 [type locality: Hawaiian Is. but according to Rathbun (1918) and Edmonson (1959) this locality must be erroneous]. — Stimpson, 1858: 48 [102] (California, Japan); 1907: 116 ( Japan). — Ortmann, 1894: 708 (California; Japan). — Rathbun, 1918: 241 (California; Galápagos Is., Japan, Korea; but not Chile, see distribution). — Tesch, 1918: 76 (Key). — Garth, 1957: 103 (invalid record in Chile; see distribution). —Edmonson, 1959: 168 (California). — Sakai, 1976: 634, pl. 218, fig. 1 ( Japan, Korea; references). — Dai & Yang, 1991: 511 ( China sea, Guangdong, Fujian, and Zhejiang). — Hendrickx, 1995: 140 (east Pacific from Oregon to Gulf of California and Rocas Alijos; references). — Cuesta & Schubart, 1998: 1501 (California). — Ng et al., 2001: 40 ( Taiwan; references).

Grapsus eydouxi H. Milne Edwards, 1853: 170 [136] ( Chile; probably an erroneous locality, see distribution).

Leptograpsus gonagrus H. Milne Edwards, 1853: 173 [139] (type locality unknown).

Type material Male preserved in alcohol ( ANSP CA 901 ) (P. Callomon, pers. comm.) .

Material Examined

East Pacific. California: Pacific Grove, 1 M 27.0 x 30.8 mm ( MNHN B12892); coll. J. E. Benedict, June 1905, 3 M 26.5 x 29.8–37.2 x 42.9 mm, 4 ov. F 27.3 x 30.1–31.9 x 36.8 mm, 2 F 25.6 x 28.4, 34.0 x 39.6 mm, plus numerous other specimens not examined ( USNM 32234 ). West Pacifi c. Japan: Enoshima, Sagami Bay , coll. M. Takeda, 15 August 1980, 1 M 31.9 x 36.6 mm ( NSMT Cr7516). — Sotobo , Chiba Prefecture, coll. T. Habe, 25 March 1975, 2 M 16.8 x 18.9, 24.9 x 29.3 mm ( NSMT Cr 6822) .

Diagnosis

Carapace with dorsal surface weakly convex, striated on gastric, hepatic, branchial regions; striae without setae. Cardiac, intestinal regions smooth or only with faint striae. Lateral margins convergent posteriorly, with single tooth behind exorbital angle ( Fig. 2a ). Front 0.6 times exorbital width, anterior margin slightly sinuous with 2 lobules distally ( Fig. 2b ). Infraorbital margin weakly dentate on inner half, deeply dentate on outer half; outer notch deep ( Fig. 14g ).

Outer face of chelae smooth with faint longitudinal line near lower margin, becoming clearly noticeable only on outer face of fixed finger; upper margin slightly carinated; tip of fingers spoon­like, glabrous ( Fig. 2c ). Ambulatory legs almost totally glabrous; carpi, propodi with several short mobile spines; dactyli with longitudal rows of long mobile spines, ending with strong, corneous claw. Lower margin of P5 merus smooth with rounded distal angle ( Fig. 2d ).

Abdominal tergites smooth; sixth somite of abdomen plus telson triangular in male ( Fig. 2e ). G1 bluntly truncated with small horn­like process distally ( Fig. 15g ).

Colour: very variable on photographs examined. Carapace green to almost totally black. Chelipeds light pink to purple or black, with a marbled pattern on the chelae. Ambulatory legs light green or purple to almost totally black.

Measurements: large size; carapace of specimens examined ranging from 26.5 x 29.8 mm to 37.2 x 42.9 mm.

Distribution

East Pacific. Oregon and California, Mexico, Galápagos. West Pacific. China, Japan, Korea, Taiwan.

The type locality given by Randall (1840), the Hawaiian Is., is certainly erroneous as this large­size and common species has never again been recorded from the islands. The type specimen was most probably collected on the California coast. Pachygrapsus crassipes was also listed as occurring in Chile by Rathbun (1918: 241) based on the fact that this is the type locality given for Grapsus eydouxi H. Milne Edwards (1853: 170) . The type of G. eydouxi has not been found at the MNHN. Garth (1957: 105) considered the type locality of Chile for G. eydouxi to be erroneous, and thus he did not include P. crassipes as part of the Chilean fauna.

Habitat Intertidal on rocky shores.

Remarks

Pachygrapsus crassipes , together with P. gracilis , P. laevimanus , P. loveridgei , P. maurus , and P. transversus , belongs to the group of species with only one tooth behind the exorbital angle. It clearly differs from these species by the shape of its G1 ( Fig. 15 ). Of this group it is morphologically close to P. transversus , another large­size species. The two can be separated by the presence of striae on the cardiac and intestinal regions of the carapace being marked only in P. transversus ( Fig. 2a , 13a ); the longitudinal stria on the outer face of the chela is unclear in P. crassipes , but deep in P. transversus ( Fig. 2c , 13c ); the ventrodistal angle of the P5 merus is rounded in P. crassipes , but it has spines in P. transversus ( Fig. 2d , 13d ); and the male abdomen is regularly triangular at its tip only in P. crassipes ( Fig. 2e , 13e ).

Pachygrapsus crassipes is common on the Pacific coasts of North and South America from Oregon to Mexico and the Galápagos Is. Stimpson (1907: 116) was the first to record it from the west Pacific, indicating that he was “unable to find a distinguishing character, however minute, between the specimens from Japan and those from California”. Pachygrapsus crassipes was reported several times thereafter from the west Pacific, including Korea ( Rathbun, 1918), Japan ( Sakai, 1976), China (Dai & Yang, 1911), and Taiwan ( Ng et al., 2001). This amphi­Pacific distribution is rather unusual, the fauna of the east and west Pacific normally being distinct. The G1 of Asian P. crassipes appears to have never been figured or compared with the American P. crassipes . The examination of the G1 of Japanese specimens (NSMT Cr7516, Cr 6822) shows them to be very similar to the American P. crassipes . Despite this, preliminary DNA analyses by C. Schubart (pers. comm.) indicate genetic differences between the Asian and American populations and, if these are confirmed by additional data (morphology, larval development, colour pattern), the two could be considered separate species.

Figures

FIGURE 2. —Pachygrapsus crassipes Randall, 1840. a) dorsal view; b) front; c) left chela outer face, d) left P5, e) male abdomen. a) male 26.5 x 29.8 mm, California (USNM 32234); b–e, male 27.0 x 30.8 mm, California (MNHN B12892).

FIGURE 13. —Pachygrapsus transversus (Gibbes, 1850). Male 17 x 22.5 mm, French Guiana (MNHN B16013): a) dorsal view; b) front; c) left chela outer face, d) right P5, e) male abdomen.

FIGURE 14. —Infra–orbital margin: a) Pachygrapsus fakaravensis Rathbun (1907), ov. female 15.0 x 16.5 mm, Taiaro, French Polynesia (MNHN B25782); b) Pachygrapsus laevimanus Stimpson, 1858, neotype male 18.0 x 21.7 mm, Sydney, Australia (AM P7478); c) Pachygrapsus minutus A. Milne­Edwards, 1873, male 5.2 x 7.0 mm, Moruroa, French Polynesia (MNHN B29273); d) Pachygrapsus planifrons de Man, 1888, male 7.0 x 9.0 mm, Rangiroa, French Polynesia (UF 1490); e) Pachygrapsus plicatus (H. Milne Edwards, 1837), male 12.1 x 15.3 mm, Taiaro, French Polynesia (MNHN B29279); f) Pachygrapsus corrugatus (von Martens, 1872) ov. female 13.6 x 15.2 mm, Virgin Is. (USNM 72340); g) Pachygrapsus crassipes Randall, 1840, male 31.9 x 36.6 mm, Sagami Bay, Japan (NSMT Cr7516); h) Pachygrapsus gracilis (de Saussure, 1858), ov. female 8.5 x 11 mm, Angola (MNHN B12903); i) Pachygrapsus loveridgei Chace, 1966, male 8.1 x 10 mm, St. Helena I. (MNHN B17836); j) Pachygrapsus marmoratus (Fabricius, 1787), female 12.7 x 14.3 mm, Préfailles, France (MNHN B22654); k) Pachygrapsus maurus (Lucas, 1846), female 12.7 x 14.3 mm, Banyuls, France (MNHN B12933); l) Pachygrapsus transversus (Gibbes, 1850), male 17.0 x 22.5 mm, French Guiana (MNHN B16013). Scale bar 1 mm.

FIGURE 15. —Male gonopods: a) Pachygrapsus fakaravensis Rathbun (1907), holotype 18.0 x 19.4 mm, Fakarava, French Polynesia (USNM 32844), right G1, abdominal face (left) and detail of terminal portion, sternal face (right); b) Pachygrapsus laevimanus Stimpson, 1858, neotype 18.0 x 21.7 mm, Sydney, Australia (AM P7478), left G1, abdominal (left) and sternal face (right), setae omitted; c) Pachygrapsus minutus A. Milne­Edwards, 1873, cl 8.2 mm, Caroline Is., lateral (left) and abdominal face (right), setae omitted; d) Pachygrapsus planifrons de Man, 1888, 9.5 x 11.8 mm, Hawaiian Is. (USNM 29350), right G1, abdominal (left) and sternal face (right); e) Pachygrapsus plicatus (H. Milne Edwards, 1837), cl 11.7 mm, Hawaiian Is., lateral (left) and abdominal face (right); f) Pachygrapsus corrugatus (von Martens, 1872), cl 8.5 mm, Ascension I., left G1 abdominal face (left) and detail of terminal portion, setae omitted (right); g) Pachygrapsus crassipes Randall, 1840, cl 35.6 mm, California, lateral (left) and abdominal face (right) setae omitted; h) Pachygrapsus gracilis (de Saussure, 1858), cl 8.7 mm, Virgin Is., lateral (left) and abdominal face (right), setae omitted; i) Pachygrapsus loveridgei Chace, 1966, holotype 10.3 x 13.1 mm, St. Helena I. (USNM 112457), left G1, abdominal (left) and sternal face (right); j) Pachygrapsus marmoratus (Fabricius, 1787), cl 30.5 mm, Gibraltar, lateral (left) and abdominal face (right), setae omitted; k) Pachygrapsus maurus (Lucas, 1846), cl 8.5 mm, Canary Is., lateral (left) and abdominal face (right) setae omitted; l) Pachygrapsus transversus (Gibbes, 1850), cl 11.1 mm, Key West, Florida, lateral (left) and abdominal face (right), setae omitted. (c, e, g–l, from Chace, 1966, fig. 10–11; f, from Manning & Chace, 1990, fig. 43). Approximate magnification x 6 (x 12 for detail of terminal portion).

FIGURE 16. —Geographic distribution of: a) Pachygrapsus crassipes Randall, 1840 (Stars); b) Pachygrapsus transversus (Gibbes, 1850) (full dots); and c) P. laevimanus Stimpson, 1858 (empty dots). a–b, mostly from literature; c) from collections examined during this study. Occurrence of P. laevimanus at Easter I. uncertain (?) and must be confirmed by examination of G1 (see text).