Oncopagurus bicristatus (A. Milne-Edwards, 1880 )

Lemaitre, Rafael, 2014, A worldwide taxonomic and distributional synthesis of the genus Oncopagurus Lemaitre, 1996 (Crustacea: Decapoda: Anomura: Parapaguridae), with descriptions of nine new species, Raffles Bulletin of Zoology 62, pp. 210-301 : 217

Oncopagurus bicristatus (A. Milne-Edwards, 1880)

Figs. 1J–T , 51

Eupagurus bicristatus A. Milne-Edwards, 1880: 43 (in part; type locality: off Fredericksted [sic.], USCGS Blake, sta 136, 17°43.10'N, 64°55.50'S).

Parapagurus bicristatus bicristatus – de Saint Laurent, 1972: 112.

Parapagurus bicristatus – Williams et al., 1989: 32.

Sympagurus bicristatus – Lemaitre, 1989: 58, figs 28–32, 40A, B; Melo, 1999: 152, figs 91, 92.

Oncopagurus bicristatus – Lemaitre, 1996: 194; McLaughlin et al., 2005: 246; Coelho et al., 2007: 10 (Table 1); Felder et al., 2009: 1071; McLaughlin et al., 2010: 38.

(For complete synonymy see Lemaitre, 1989)

Type material. Holotype, off Frederiksted [ U.S. Virgin Islands], Caribbean Sea, USCGS Blake, sta 136, 17°43.10'N, 64°55.50'S: M 3.2 mm ( MCZ 4039 ).

Additional material. See Lemaitre (1989).

Diagnosis. Shield ( Fig. 1J ) about as broad as long; rostrum broadly rounded, weakly produced to obsolete, with short mid-dorsal ridge; lateral projections subtriangular, slightly in advance of rostrum, often terminating in small spine. Ocular peduncles usually more than half length of shield, each with dorsal row of setae; corneas weakly dilated. Ocular acicles subtriangular, terminating in strong spine. Antennular peduncle exceeding distal margin of cornea by entire length of ultimate segment. Antennal peduncle not exceeding distal margin of cornea; fourth segment with dorsodistal spine; second segment terminating in strong, simple or multifid spine, mesial margin with spine on dorsodistal angle; first segment with 1 or 2 small spines on lateral face; acicle nearly straight (in dorsal view), usually not exceeding distal margin of cornea, terminating in strong spine, mesial margin armed with row of 10–14 spines; flagellum exceeding extended right cheliped, articles with numerous setae <1–3 flagellar articles in length. Third maxilliped with crista dentata of about 10 teeth, proximal teeth only slightly larger than distal. Right cheliped ( Fig. 1K–M ) with moderately dense, simple or plumose setae, proportions and armature of chela strongly influenced by size and sexual dimorphism [see Variations in Lemaitre (1989), as Sympagurus bicristatus ], chela operculate; dactyl set at strongly oblique angle to longitudinal axis of palm; palm about as long as broad or slightly broader than long, dorsal face with scattered small tubercles or spines, dorsolateral, dorsomesial and ventromesial margins well delimited by row of blunt to sharp spines, mesial face strongly concave and expanded distomesially (more so in large males (sl> 4.0 mm), ventral surface smooth; carpus with dorsolateral margin rounded or sometimes well delimited distally by row of spines, dorsal face with numerous, well-spaced small spines or tubercles. Left cheliped usually weakly calcified on dorsolateral face of carpus; palm unarmed except for scattered setae on dorsal face and long setae on dorsomesial margin; carpus with strong dorsodistal spine and long setae dorsally. Ambulatory legs with dactyls ( Fig. 1N ) each with ventromesial row of about 7–8 slender corneous spines; carpus with small dorsodistal spine. Anterior lobe of sternite XII (between second ambulatory legs) rounded, setose, with subterminal spine. Fourth pereopod propodal rasp ( Fig. 1O ) with 1 row of rounded scales at least distally. Fifth pereopod propodal rasp extending to or beyond mid-length of segment. Uropods and telson markedly asymmetrical; telson ( Fig. 1P ) lacking transverse suture, posterior lobes separated by shallow cleft, terminal margin of lobes armed with often strongly curved corneous spines. Male with paired first and second gonopods ( Fig. 1Q–T ); first gonopods poorly developed, at most consisting of short buds; second gonopods weakly developed, symmetrical (2-segmented) or asymmetrical with left 2-segmented and right 1-segmented. Female with vestigial second right pleopod.

Variations. See Lemaitre (1989, as Sympagurus bicristatus )

Colouration. Unknown.

Habitat. Gastropod shells frequently with one or more anthozoan polyps (actinians or zoanthids) attached.

Distribution. Western Atlantic, from Straits of Florida and Gulf of Mexico, to off the coast of Maranhao, Brazil; eastern Atlantic, from Canary Islands and Cape Verde Islands. Depth: 270–1,070 m.

Remarks. (See Oncopagurus africanus and O. gracilis ).

Figures

Fig. 1. A–I, Oncopagurus africanus (de Saint Laurent, 1972), paratype, male 5.2 mm, Angola (MNHN Pg 2689): A, shield and cephalic appendages, dorsal; B, carpus and chela of right cheliped, mesial; C, D, chela of same, dorsal (C) and lateral (D); E, dactyl of first left ambulatory leg, mesial; F, propodus and dactyl of right fourth pereopod, lateral; G, telson, dorsal; H, male sternite XIV, coxae of fifth pereopods, and first gonopods, ventral; I, male left second pleopod, posteromesial. J–T, Oncopagurus bicristatus (A. Milne-Edwards, 1880), J, L, M, P, male 3.1 mm, Straits of Florida (USNM 1100616); K, female 1.9 mm, Straits of Florida (USNM 1100616); N, O, R, S, male 3.0 mm, Caribbean Sea (UMML 32:4607); Q, male 4.4 mm Straits of Florida (UMML 32:4610); T, male 2.6 mm, Straits of Florida (USNM 1100615): J, shield and cephalic appendages, dorsal; K, carpus and chela of right cheliped of female, dorsal; L, carpus and chela of right cheliped of male, dorsal; M, right chela of same, lateral; N, dactyl of first left ambulatory leg, mesial; O, propodus and dactyl of left fourth pereopod, lateral; P, telson, dorsal; Q, male sternite XIV, coxae of fifth pereopods, and anterior portion of pleon with first and second gonopods, ventral. Scale bars = 2 mm (A, E); 3 mm (B–D); 1 mm (F, G, I); 2 mm (H); 1 mm (J, O, P); 2 mm (K–N); 2 mm (Q); 0.5 mm (R–T). [Adapted from Lemaitre (1989, 1990)].

Fig. 51. Bathymetric distribution of Oncopagurus species from the world, with maximum and minimum depths (meters) indicated for each.