Pachygrapsus maurus ( Lucas, 1846 )

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: 28-31

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-ED5C-FFE6-6C1C-FAD8FC59FD78

treatment provided by

Felipe

scientific name

Pachygrapsus maurus ( Lucas, 1846 )
status

 

Pachygrapsus maurus ( Lucas, 1846)   ( Figures 8a–e View FIGURE 8 , 14k View FIGURE 14 , 15k View FIGURE 15 )

Grapsus maurus Lucas, 1846: 20   , vol. 4, pl. 2, fig. 5 [type locality: Oran, Algeria]

Leptograpsus maurus   —H. Milne Edwards, 1853: 173 ( Algeria).

Pachygrapsus simplex   — Stimpson, 1858: 48 [102] (Madeira); 1907: 116 (Madeira).

Pachygrapsus maurus   — Heller, 1863: 112 ( Algeria). — Kingsley, 1880: 199 (Key; synonymy). — Rathbun, 1918: 244 (Azores, Canary Is.; synonymy). — Bouvier, 1940: 290, fig. 180 ( Algeria, Madeira, Azores). —Zariquiez Álvarez, 1948: 291, pl. 24, fig. 1­2 ( Spain); 1968: 425, fig. 140b, 141a ( Spain). — Falciai & Minervini, 1992: 234. —d’Udekem d’Acoz, 1994: 36 ( Greece); 1999: 255, unnumbered fig. p. 52 (references, distribution, ecology); 2005 (photographs, reference, distribution). — González Pérez, 1995: 223, photo 164 (Canary Is.).

Type material

Probably not extant. According to Rathbun (1918: 244) the type was at MNHN but the first author was unable to locate it.

Material Examined

Central Atlantic. Azores: São Miguel I., coll. Collette & R. B. Manning, 13 March 1963, 1 M 9.0 x 10.4 mm ( USNM 170343 View Materials ). Terceira I., unknown coll., 1 F 6.5 x 7.7 mm ( USNM 18627 View Materials ; see remarks)   .

East Atlantic. Madeira: Funchal, J. Panousse, 1973, 2 M 8.7 x 10.0, 9.6 x 10.7 mm ( MNHN B12931 View Materials )   . Canar y Is.: Gran Canaria, Guia I., coll. U.S. Fish Commission, September 1894, and unknown coll., September 1994, 3 M 6.7 x 7.9–9.2 x 10.4 mm, 1 ov. F 7.4–8.2 mm, 4 juveniles ( USNM 44529 View Materials )   . Mediterranean Sea. France: Banyuls, coll. and det. J. Forest, 1 F 12.7 x 14.3 mm ( MNHN B12933 View Materials )   ; Spain, Cadaqués, coll. and det. J. Forest, July 1955, 4 M 6.9 x 8.4–9.4 x 10.6 mm, 1 ov. F 6.0 x 7.0 mm ( MNHN B12932 View Materials )   .

Diagnosis

Carapace with glabrous striae on gastric, hepatic, branchial regions; mesogastric, cardiac regions with shorter, fainter striae, intestinal region almost smooth; lateral margins weakly convergent posteriorly with tooth behind exorbital angle ( Fig. 8a View FIGURE 8 ). Front 0.6 times exorbital width; anterior margin sinuous ( Fig. 8b View FIGURE 8 ). Infraorbital margin slightly denticulated on inner half, almost smooth on outer half; outer notch deep, obliquely oriented ( Fig. 14k View FIGURE 14 ).

Outer face of palm regularly convex with numerous small pits; distal half with faint stria above lower margin ( Fig. 8c View FIGURE 8 ); dorsal margin of palm rounded with faint oblique lines on inner face; cutting edges of fingers with triangular teeth, tip of fingers corneous, spoonlike, glabrous ( Fig. 8c View FIGURE 8 ). P2–P3 propodi without brush of setae, at most with a denser area of stiff setae on smallest specimens. Lower margin of P5 merus smooth; distoventral angle rounded or feebly indented ( Fig. 8d View FIGURE 8 ).

Abdominal tergites smooth. Sixth somite of abdomen plus telson triangular in male ( Fig. 8e View FIGURE 8 ). G1 bluntly rounded with a low corneous gutter­like process ( Fig. 15k View FIGURE 15 ).

Colour (d’Udekem d’Acoz, pers. comm.): Large round bluish/greyish or pale yellowish spots on a black background. In some specimens the spots are confluent.

Measurements: medium size; carapace of specimens examined ranging from 6.5 x 7.7–12.7 x 14.3 mm, smallest ovigerous female 6.0 x 7.0 mm. D’Udekem d’Acoz (2005) indicates a cw of about 20 mm.

Distribution

West Atlantic and Mediterranean. Azores, Madeira, Canary Is. (common), Mediterranean. Patchy distribution as a result of the rarity of suitable habitats   .

Habitat Intertidal on rocks and cliffs with strong wave exposure (d’Udekem d’Acoz, 2005).

Remarks

Pachygrapsus maurus   appears more closely related to species of Pachygrapsus   that have no brush of setae on the P2 or P3 propodi. This brush of setae was absent on most of the specimens examined, however. It seems to be a juvenile character that disappears in adults because it was found in the three smallest specimens examined: female 6.5 x 7.7 mm, Terceira ( USNM 18627 View Materials ), and two males 6.9 x 8.4, 7.4 x 8.4 mm, Cadaqués , Spain ( MNHN B12932 View Materials )   .

Pachygrapsus maurus   and P. marmoratus   occur sympatrically in the Azores, Madeira, Canary Is., and the Mediterranean. Pachygrapsus maurus   is smaller (cw about 20 mm) than P. marmoratus   (cw about 40 mm), and it has only one tooth behind the exorbital angle instead of two in P. marmoratus   .

Pachygrapsus maurus   is morphologically close to P. transversus   . but P. transversus   is larger than P.maurus   . The G1 is clearly distinct, with a petal­like tip in P. transversus   ( Fig. 15l View FIGURE 15 ) instead of bluntly rounded with a short corneous process in P. maurus   ( Fig. 15k View FIGURE 15 ). Small females of these two species are more difficult to separate on a morphological basis. A small female of P. maurus   from the Azores (USNM 18627) showed a brush of setae on the P2 propodi, and was thus very similar to females of P. transversus   of similar size. It was identified as P. maurus   because the distoventral angles of the P5 merus are rounded, without spines, whereas P. transversus   has 3–4 spines.

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Grapsidae

Genus

Pachygrapsus

Loc

Pachygrapsus maurus ( Lucas, 1846 )

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

Pachygrapsus maurus

Gonzalez Perez, J. A. 1995: 223
Falciai, L. & Minervini, R. 1992: 234
Zariquiey Alvarez, R. 1948: 291
Bouvier E. - L. 1940: 290
Rathbun, M. J. 1918: 244
Kingsley, J. S. 1880: 199
Heller, C. 1863: 112
1863
Loc

Pachygrapsus simplex

Stimpson, W. 1858: 48
1858
Loc

Leptograpsus maurus

Milne Edwards, H. 1853: 173
1853
Loc

Grapsus maurus

Lucas, H. 1846: 20
1846