Chasmocarcinus longipes Garth 1940
Creators: name: Ng, Peter K. L.
name: Castro, Peter
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Chasmocarcinidae
Chasmocarcinus
Chasmocarcinus longipes

description: Chasmocarcinus longipes Garth, 1940
(Figs. 4 F; 22C; 29F; 36I, J; 50B; 57B; 65E‒H; 85A; 89G; 100A, B)
Chasmocarcinus longipes Garth, 1940: 90, pl. 26 [type localilty: Gulf of Chiriquí, Panama]; 1948: 52 [Panama, Colombia, Ecuador].—von Prahl 1986:98 [Colombia]—Lemaitre & Álvarez León 1992: 55 [in list].— Hendrickx 1995: 139 [in list].—Ng et al. 2008: 76 [in list].
Chasmocarcinus panamensis Serène, 1964a: 258, fig. 19, pl. 23, figs. A, B. [Gulf of Panama].—Ng et al. 2008: 76 [in list].
Type material. Holotype female (8.3 × 10.0 mm) (LACM-CR-1938.1), Panama, Gulf of Panama, Secas Is., Allan Hancock Expedition of 1938, Velero III, stn 865-38, 5.4 m, 0 2.03.1938.
Paratypes: ALLAN HANCOCK EXPEDITIONS: 1 male (5.5 × 6.4 mm), 1 female (5.6 × 6.8 mm) (USNM 78785), Colombia, Puerto Utría, Velero III, stn 233-34, 37 m, 14.02.1934; 3 males (4.2 × 5.7 mm, 5.0 × 6.2 mm, 5.4 × 6.9 mm) (LACM-CR-1934.1), stn 233-34, 14.02.1934.
Other material examined. Panama. MONSUNEN EXPEDITION (1933-1934) (holotype male of Chasmocarcinus panamensis Serène, 1964) (6.9 × 8.0 mm) (ZMUC CRU- 7697), Isla del Rey, Pearl Is., Gulf of Panama, 5.01.1934. —ALLAN HANCOCK EXPEDITION (1934): 1 male (5.0 × 5.9 mm), 1 female (5.0 × 5.9 mm) (MBPC 16364), Bahía Honda, stn 248-34, 46– 55 m, 22.02.1934.— ALLAN HANCOCK EXPEDITION (1938): holotype female (8.3 × 10.0 mm) (LACM), Secas Is., Velero III, stn 865-38, 5.4 m, 02.03.1938.— 5 males (largest 6.8 × 5.8 mm), 3 females (largest 8.0 × 6.1 mm) (ZRC 2013.1418), Bay of Panama, Urica, stn 2, 07°24.4’N, 80°13.7’W, 15.02.2007.
Colombia. ALLAN HANCOCK EXPEDITION (1934): 1 male (3.9 × 4.8 mm), stn 232-34, shore (MBPC 16365); 1 male (5.8 × 7.0 mm), 1 female (4.1 × 5.0 mm) (MBPC 16366), Cobita Bay, stn 230-34, 54.6 m, 14.02.1934.
Ecuador. ALLAN HANCOCK EXPEDITION (1934): 1 male (5.6 × 6.6 mm), 1 female (5.6 × 7.2 mm) (MBPC16367), Cape San Francisco, stn 216-34, 36.4 m, 11.02.1934.
Diagnosis. Carapace (Figs. 4 F; 100A, B; Garth 1940: pl. 26, fig. 1) with granular ridge along anterolateral margins. Orbits (Fig. 22 C; Garth 1940: pl. 26, fig. 5) long, eye peduncles proportionally long. Epistome (Fig. 22 C) with salient, trapezoid median lobe with median fissure, lateral margins straight to slightly curved. Antennular articles relatively short (Fig. 22 C). Third maxilliped (Fig. 29 F; Garth 1940: pl. 26, fig. 4; Serène 1964a: fig. 19c, as C. panamensis) merus ovate; ischium rectangular, longer than merus. Bulging pterygostomial region, clearly visible from dorsal view. Fingers of major chela of large males (Figs. 36 I; 100B; Garth 1940: pl. 26, figs. 2, 3) proportionally short, only slightly longer than enlarged propodus in dorsal view; pollex as long as dactylus; few large teeth, slightly larger proximally. Fingers of minor chela of both sexes (Fig. 36 J) scissor-like; with small, sharp teeth. Anterior margin of ventral surface of propodus, proximal portion of pollex of major chela of large males smooth, without tufts of long setae. Inner margin of cheliped carpus (Fig. 4 F; Garth 1940: pl. 26, fig. 1) with low, blunt tooth (smooth in small individuals). Ambulatory legs (Fig. 4 F; Garth 1940: pl. 26, fig. 1) proportionally short, folded P5 merus only reaching middle portion of anterolateral margin. Fused thoracic sternites 1, 2 (Fig. 50 B) broadly triangular, proportionally wide, short. Male pleon (Figs. 50 B, 57B) with proportionally long, narrow telson. G1 (Fig. 65 E‒G; Serène 1964a: fig. 19c, as C. panamensis) slender, long, nearly straight, not expanded distally, with only few spinules on distal end. G2 (Fig. 65 H; Serène 1964a: fig. 19c, as C. panamensis) shorter than G1, with short distal segment. Female pleon (Fig. 85 A) with lateral margins of somites strongly convex; telson proportionally short. Sterno-pleonal cavity of female (Fig. 89 G) moderately shallow, vulvae close together.
Colour. The carapace is yellowish beige in life, the chelipeds and ambulatory legs white (Fig. 100 A, B).
Remarks. Garth (1940: 53) remarked that the morphology of the chelipeds and ambulatory legs can be used to distinguish C. longipes from the often sympatric C. latipes, especially the stout legs of C. latipes and the high propodus of the major chela of large males of C. longipes. Diagnostic for C. longipes is a bulging pterygostomial region as in its Atlantic congeners and different from the gently convex region of C. latipes, and the orbits are conspicuously long (Fig. 22 C). Also characteristic of C. longipes is an epistome with slightly curved lateral margins (Fig. 22 C) similar to C. latipes, its eastern Pacific congener, but different from the straight lateral margins of all Atlantic congeners.
Garth (1948: 91, pl. 26, fig. 5) stated in the description of the species that the epistome is “diamond shaped”, but the illustration of the female holotype shows a trapezoid median lobe as in all specimens examined.
Serène (1964a) was obviously unaware of Garth’s description of C. longipes as a new species (Garth 1940). It was not listed on his list of species of Chasmocarcinus (Serène 1964a: 258) nor in differences between his new species and other species of Chasmocarcinus (detailed differences in contrast to four species, all from the Western Atlantic) nor Garth’s reference at the end of the paper.
Distribution. Tropical Eastern Pacific: Costa Rica to Ecuador. Depth: “shore”— 90 m.
description: Published as part of Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), pp. 1-182 in Zootaxa 4209 (1) on pages 23-25, DOI: 10.11646/zootaxa.4209.1.1, http://zenodo.org/record/272646