Pachygrapsus minutus A. Milne­Edwards, 1873, A. Milne-Edwards, 1873

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: 31-34

publication ID

http://doi.org/ 10.11646/zootaxa.1015.1.1

publication LSID

lsid:zoobank.org:pub:67DBD7AA-FA11-4F32-811B-0A9EFF4C668F

persistent identifier

http://treatment.plazi.org/id/6C3D8794-ED59-FFD9-6C1C-FC90FD0FFC18

treatment provided by

Felipe

scientific name

Pachygrapsus minutus A. Milne­Edwards, 1873
status

 

Pachygrapsus minutus A. Milne­Edwards, 1873   ( Figures 9a–d View FIGURE 9 , 14c View FIGURE 14 , 15c View FIGURE 15 )

Pachygrapsus minutus A. Milne­Edwards, 1873a: 292   , pl. 14, fig. 2 [type locality: New Caledonia]. — Cano, 1889: 240 (Hawaiian Is.). — Alcock, 1900: 399 (Mergui Archipelago). — Rathbun, 1906: 840 (Hawaiian Is.); 1907: 30 (Tuamotu Archip.; Caroline Is.); 1911: 242 ( Seychelles). — Tesch, 1918: 77 (Celebes; synonymy). — Balss, 1934a: 229 (Christmas I.; synonymy). — Boone, 1934: 180, pl. 91 ( Samoa). — Tweedie, 1936: 46 (Christmas I.); 1950a: 94 ( Malaysia). — Schmitt, 1939: 22 ( Clipperton). — Holthuis, 1953: 31 ( Kiribati); 1977: 158 (Red Sea). — Hertlein & Emerson, 1957: 5 ( Clipperton). —Edmonson, 1959: 171 ( Fiji, Samoa, Line Is., Hawaiian Is.). — Forest & Guinot, 1961: 155 (Society Is., Tuamotu Archip.). — Crosnier, 1965: 26, fig. 23, 29–30 ( Madagascar). — Garth, 1965: 27, fig. 14 ( Clipperton); 1992: 4 (Revillagigedo Is.). — Chace, 1966: 644, fig. 11e (Caroline Is.; synonymy). — Sakai, 1976: 635, fig. 347a–c ( Japan). — Monteforte, 1984: 172, annex 1, tab. a (Society Is., Tuamotu Archip.); 1987: 9 (Society Is.). — Peyrot­Clausade, 1985: 462 (Society Is.); 1989: 113 (Tuamotu Archip.). — Dai & Yang, 1991: 510 ( China sea). — Ng et al., 2001: 41 ( Taiwan; references). — Davie, 2002: 218 (Christmas I., Ashmore and Cartier Is., Middleton and Elizabeth reefs). — Ng & Davie, 2002: 379 ( Thailand). — Paulay et al., 2003: 495 (Mariana Is.). — Yeo et al., 2004: 88 (Anambas Is., South China Sea).

Sesarma murrayi Calman, 1909: 708   (Christmas I.).

Pachygrapsus murrayi   — Ward, 1934: 25 (Christmas I.).

Type material

Five males syntypes, 5.9 x 8.0–7.6 x 10.4 mm, poor condition ( MNHN B3582 View Materials ). Male 7.6 x 10.4 mm is herein designated as lectotype, the remaining four specimens as paralectotypes   .

Material Examined

New Caledonia: Types specimens, coll. M. Balansa, 5 M 5.9 x 8.0–7.6 x 10.4 mm (poor condition) (dry collection, MNHN B3582 View Materials )   .

Caroline Is. Palau: landward from Ngchesau reef, supra­tidal karst, exposure on top of reef, coll. G. Paulay, 7 March 2003, 1 ov. F 7.2 x 10.3 mm ( UF 3882)   . — Yap: Maap I., high intertidal, under rocks and plant debris, coll. G. Paulay, 1 April 2000, 1 M 3.6 x 5.1 mm ( UF 8000)   .

Mariana Is. Saipan: Garapan pier, reef flat, under rocks 1 m, coll. J. Stammer, 15 November 1997, 1 M 6.6 x 9.4 mm, 4 F 5.2 x 7.4–6.1 x 8.7 mm ( UF 590)   . — Guam: 13°26.74’N, 144°39.54’E, Apra Harbor on mooring buoy 16, 0–10 m, coll. G. Paulay, 23 August 2000, 1 M 6.4 x 8.7 mm ( UF 3173) GoogleMaps   ; Tagachang reef flat, intertidal, under rocks, coll. G. Paulay, 6 July 1997, 2 M 4.4 x 6.3, 5.9 x 8.5 mm ( UF 123)   .

Niue: Alofi, Utuko reef flat, exposed on reef surface, coll. B. Holthuis & G. Paulay, 13 September 1991, 1 M 3.5 x 5.4 mm ( UF 2246), 1 F 4.4 x 6.6 mm ( UF 2250)   .

French Polynesia. Gambier Is.: Aukena I., intertidal, RV Marara   campaign, coll. J. Poupin, April 1995, 1 ov. F 5.7 x 8.0 mm MNHN ( B29270 View Materials )   . — Society Is.: Tahiti , intertidal, RV Marara   campaign, coll. J. Poupin, November 1995, 1 M 4.2 x 5.4 mm ( MNHN B29271 View Materials )   . — Marquesas Is.: Nuku Hiva I., Taiohae Bay , intertidal, RV Marara   campaign, coll. J. Poupin, 9 February 1996, 1 ov. F 3.2 x 5.0 mm ( MNHN B29272 View Materials )   . — Tuamotu Archip.: Moruroa Atoll , lagoon, intertidal in rubbles, RV Marara   campaign, coll. J. Poupin, October 1995, 8 M 4.0 x 5.6–5.2 x 7.0 mm, 6 ov. F 3.3 x 4.7–5.7 x 8.0 mm, 5 F 3.3 x 4.8–4.9 x 7.0 mm ( MNHN B29273 View Materials )   .

Clipperton Atoll. Among rocks at low tide, Jean­Louis Etienne Expedition to Clipperton, coll. J. Poupin, February 2005, 13 M 4.0 x 5.5–7.5 x 9.0 mm, 1 ov. F 4.0 x 5.0 mm, 8 F 3.5 x 5.0–8.0 x 10.0 mm ( MNHN B29860 View Materials )   .

Diagnosis

Small­size species. Carapace subtriangular, lateral margins strongly convergent posteriorly with no tooth behind external orbital angle ( Fig. 9a View FIGURE 9 ). Dorsal surface weakly convex with faint transverse striae on protogastric, hepatic, branchial regions; striae without setae or only few; mesogastric region smooth or with few striae; cardiac, intestinal regions smooth. Front 0.5 times width at exorbital angles; anterior margin sinuous ( Fig. 9b View FIGURE 9 ). Infraorbital margin minutely dentate over entire length, separated from exorbital tooth by very low indentation ( Fig. 14c View FIGURE 14 ).

Chelipeds equal. Outer faces of chelae regularly convex, with faint longitudinal stria near lower margins, extending to fixed finger; tip of fingers spoon­like, without setae ( Fig. 9c View FIGURE 9 ). Dorsal margins of P2–P4 carpi, propodi with scattered long setae; woolly tomentum on P2 carpi, propodi of females, juveniles. Lower margin of P5 merus with 1–2 submedian tubercles and 2 spines of unequal size at distal angle ( Fig. 9d View FIGURE 9 ).

Abdominal tergites smooth; sixth somite of abdomen plus telson triangular in male ( Fig. 9e View FIGURE 9 ). G1 rounded at tip with short gutter­like process at tip, vertically oriented ( Fig. 15c View FIGURE 15 ).

Colour (from Clipperton specimens): carapace and legs with large and irregular patches of brown on a white to cream background. The brown patches form more or less transverse bands on the segments of the ambulatory legs.

Measurements: small size; carapace usually about 5 x 7 mm; carapace of specimens examined ranging from: males 3.5 x 5.4–6.6 x 9.4 mm; females 3.3 x 4.4–7.2 x 10.3 mm; smallest ovigerous female is 3.2 x 5.0 mm.

Distribution

Indo­West Pacific from Red Sea to Mexican oceanic islands: Madagascar, Thailand, Indonesia, Australia, China, Japan, west and east Pacific islands (Caroline Is., Mari­

ana Is., Fiji, Niue, Kiribati, Samoa, Hawaiian Is., Line Is., French Polynesia, Clipperton, Revillagigedo Is.).

Habitat Rocks and rubble in the intertidal zone.

Remarks

Pachygrapsus minutus   is conspicuous by its small size. It is morphologically close to the similar­sized P. planifrons De Man, 1888   , but the two can be easily separated. The front is straighter in P. planifrons   ( Fig. 9b View FIGURE 9 , 10b View FIGURE 10 ) than in P. minutus   , the tips of the cheliped fingers are furnished with setae in P. planifrons   but are absent in P. minutus   ( Fig. 9c View FIGURE 9 , 10c View FIGURE 10 ), the submedian tubercle on the lower margin of the P5 merus is absent in P. planifrons   ( Fig. 9d View FIGURE 9 , 10d View FIGURE 10 ), and the G1 has a rounded tip with a short vertical gutter­like process in P. minutus   ( Fig. 15c View FIGURE 15 ) instead of a petal­like tip in P. planifrons   ( Fig. 15d View FIGURE 15 ). Pachygrapsus minutus   is also morphologically close to P. propinquus De Man, 1908   . The similarities between the two are discussed under P. propinquus   .

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Grapsidae

Genus

Pachygrapsus

Loc

Pachygrapsus minutus A. Milne­Edwards, 1873

Poupin, Joseph, Davie, Peter J. F. & Cexus, Jean-Christophe 2005
2005
Loc

Pachygrapsus murrayi

Ward, M. 1934: 25
1934
Loc

Sesarma murrayi

Calman, W. T. 1909: 708
1909
Loc

Pachygrapsus minutus A. Milne­Edwards, 1873a: 292

Yeo, D. C. J. & Rahayu, D. & Ng, P. K. L. 2004: 88
Paulay, G. & Kropp, R. & Ng, P. K. L. & Eldredge, L. G. 2003: 495
Davie, P. J. F. 2002: 218
Ng, P. K. L. & Davie, P. J. F. 2002: 379
Ng, P. K. L. & Wang, C. H. & Ho, P. H. & Shih, H. T. 2001: 41
Dai, A. & Yang, S. 1991: 510
Peyrot-Clausade, M. 1985: 462
Monteforte, M. 1984: 172
Sakai, T. 1976: 635
Chace, F. A. 1966: 644
Crosnier, A. 1965: 26
Garth, J. S. 1965: 27
Forest, J. & Guinot, D. 1961: 155
Hertlein, L. G. & Emerson, W. K. 1957: 5
Holthuis, L. B. 1953: 31
Schmitt, W. L. 1939: 22
Tweedie, M. W. F. 1936: 46
Balss, H. 1934: 229
Boone, L. 1934: 180
Tesch, J. J. 1918: 77
Rathbun, M. J. 1906: 840
Alcock, A. 1900: 399
Cano, G. 1889: 240
Milne-Edwards, A. 1873: 292
1873