Pachygrapsus loveridgei Chace, 1966

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: 23-25

publication ID

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

publication LSID

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

DOI

http://doi.org/10.5281/zenodo.5049292

persistent identifier

http://treatment.plazi.org/id/6C3D8794-ED51-FFE0-6C1C-FDE8FD4FFB30

treatment provided by

Felipe

scientific name

Pachygrapsus loveridgei Chace, 1966
status

 

Pachygrapsus loveridgei Chace, 1966   ( Figures 6a–e View FIGURE 6 , 14i View FIGURE 14 , 15i View FIGURE 15 )

Pachygrapsus loveridgei Chace, 1966: 640   , fig. 9–10 [type locality: St. Helena I.]. — Manning & Chace, 1990: 66 ( Ascension I.).

Pachygrapsus transversus   — Miers, 1881: 432 ( Ascension I.) [Not Pachygrapsus transversus ( Gibbes, 1850)   ].

Type material Male holotype 10.3 x 13.1 mm ( USNM 112457 View Materials ) and 6 paratypes ( USNM 112467 View Materials )   .

Material Examined

Central Atlantic. St. Helena I.: Rupert’s Bay , on buoy cable, coll. A. Loveridge, 18 March 1960, 1 M 10.3 x 13.1 mm (Holotype USNM 112457 View Materials )   ; 11 February 1963, 3 M 5.5 x 6.8–7.7 x 9.5 mm, 1 F 6.2 x 7.9 mm, 2 ov. F. 5.0 x 6.7, 7.2 x 8.6 mm (Paratype USNM 112467 View Materials )   ; 1 M 8.1 x 10.0 mm ( MNHN B17836 View Materials )   .

Diagnosis

Carapace dorsal surface markedly convex; with glabrous striae on protogastric, hepatic, branchial region; mesogastric, cardiac, intestinal region smooth or with only few short striae ( Fig. 6a View FIGURE 6 ). Lateral margins convergent posteriorly, with only one tooth behind exorbital angle. Anterior margin of front sinuous, 0.5 times exorbital width ( Fig. 6b View FIGURE 6 ). Infraorbital margin minutely denticulate, with shallow outer notch ( Fig. 14i View FIGURE 14 ).

Outer face of chelae regularly convex, smooth except for conspicuous longitudinal line near lower margin, running nearly entire length of palm to tip of fixed finger ( Fig. 6c View FIGURE 6 ). Cutting edges of fingers narrowly gaping, with several triangular teeth. Tip of fingers corneous, spoon­like, glabrous.

Ambulatory legs with several scattered long bristles. P2 propodi with plumose setae on anterodorsal surface, forming light brush of setae. Lower margin of P5 with 1–3 submedian tubercles; distoventral angle with 2–3 spines ( Fig. 6d View FIGURE 6 ).

Abdominal tergites smooth; sixth somite of male broadly subrectangular, not triangular with telson ( Fig. 6e View FIGURE 6 ). Distal process of G1 stout, sickle­like tip ( Fig. 15i View FIGURE 15 ).

Colour: Live coloration unknown. Chace (1966: 643) indicated the colour of freshly preserved specimens as “the carapace is mottled grayish brown with all transverse striae dark brown; chelipeds dark reddish brown dorsally, fading to light tan on outer surface of palm and to nearly white near tip of fingers; ambulatory legs mottled with brown, gray, and tan, proximal and distal ends of propodus and proximal end of dactyl nearly white, giving banded appearance to legs.”

Measurements. Medium size; carapace of specimens examined ranging from 5.0 x 6.7–10.3 x 13.1 mm. Chace (1966) and Manning & Chace (1990) indicated that cl varies between 1.9–12.4 mm, with 3.2 mm for the smallest ovigerous females.

Distribution Central Atlantic: Ascension and St. Helena islands.

Habitat

Intertidal, but also on buoys, associated with barnacles, from near the surface to 7 meters.

Remarks

Pachygrapsus loveridgei   is morphologically close to P. transversus ( Gibbes, 1850)   . Both species have only one tooth on the lateral margins of the carapace behind exorbital angle, a conspicuous line on the outer face of the chelae near the lower margin, a brush of setae on the P2 propodi, and a male abdomen that is not apically triangular. P. loveridgei   is smaller in size, the carapace is more convex, and the chitinous terminal portion of the G1 is broadly sickle shaped, rather than obliquely T­shaped as in P. transversus   ( Fig. 15i, l View FIGURE 15 ).

Chace (1966: 644) indicated that 85 of the 211 specimens examined from St. Helena I. were found living near the surface on a buoy. This sporadic semi­pelagic way of life, along with its small size and markedly convex carapace, suggest affinities with species of Planes Bowdich   , especially Planes marinus Rathbun, 1911   , a species at one time included Pachygrapsus   (see Chace, 1951).

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Grapsidae

Genus

Pachygrapsus

Loc

Pachygrapsus loveridgei Chace, 1966

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

Pachygrapsus loveridgei

Manning, R. B. & Chace, F. A. 1990: 66
Chace, F. A. 1966: 640
1966
Loc

Pachygrapsus transversus

Miers, E. J. 1881: 432
1881