Oncopagurus cidaris Lemaitre, 1996

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 : 229-231

Oncopagurus cidaris Lemaitre, 1996

Figs. 10A–J , 51

Oncopagurus cidaris Lemaitre, 1996: 204 , figs 22, 23 (type locality: off Tully, Queensland, Australia, CIDARIS I, sta 1–3, 18°07.9'S, 147°35.7'E); Zhadan, 1997: 63 (table); Davie, 2002: 88; Poore, 2004: 282, fig. 81a; McLaughlin et al., 2010: 39.

Type material. Holotype, off Tully , Queensland, Australia, CIDARIS I sta 1–3, 18°07.9'S, 147°35.7'E, 956–969 m, 6 May 1986: M 2.6 mm ( QM W16596).

Paratypes: see Lemaitre (1996).

Additional material. Philippines: MUSORSTOM 3: sta CP 88, 14°00'S, 120°17'E, 183–187 m, 31 May 1985: 1 M 2.5 mm, 1 ov F 2.3 mm ( MNHN Pg.); sta CP 91, 14°00'S, 120°18'E, 190–203 m, 31 May 1985: 1 M 1.9 mm ( MNHN Pg.); sta CP 100, 14°00'S, 120°18'E, 189–199 m, 1 June 1985: 1 M 2.3 mm ( MNHN Pg.) .

Diagnosis. Shield ( Fig. 10A ) as broad as long; rostrum broadly rounded, weakly produced, with short mid-dorsal ridge; lateral projections subtriangular, terminating bluntly. Ocular peduncles more than half length of shield, with dorsal row of long setae; corneas weakly dilated. Ocular acicles subtriangular, terminating in strong spine. Antennular peduncle ( Fig. 10A ) exceeding distal margin of cornea by entire length of ultimate segment. Antennal peduncle ( Fig. 10A ) reaching distal margin of cornea; fourth segment with strong dorsodistal spine; second segment with terminating in strong, simple spine, mesial margin with spine on dorsodistal angle; first segment with 1 small spine on lateral face; acicle slightly curved outward (in dorsal view), at most slightly exceeding distal margin of cornea, terminating in strong spine, mesial margin armed with row of 5–9 spines; flagellum exceeding extended right cheliped, articles with numerous setae <1–3 flagellar articles in length. Third maxilliped with crista dentata of about 8 teeth, proximal 2 or 3 teeth distinctly larger than distal teeth. Right cheliped ( Fig. 10B, C ) with chela operculate, having moderately dense, plumose setae on distal half of chela; dactyl set at strongly oblique angle to longitudinal axis of palm; palm longer than broad, dorsal surface smooth except for scattered small tubercles, lateral margin well delimited by row of blunt to sharp spines, mesial face rounded, dorsomesial margin delimited by row of small blunt or sharp spines, ventral surface smooth; carpus with dorsolateral margin rounded or sometimes well delimited distally by row of spines, dorsal face with numerous, wellspaced small spines or tubercles. Left cheliped usually weakly calcified on dorsolateral surfaces of merus and 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 dactyl ( Fig. 10D ) each having ventromesial row of 7–9 slender corneous spines; carpus with small, blunt or sharp dorsodistal spine. Anterior lobe of sternite XII (between second ambulatory legs) rounded, setose, unarmed. Fourth pereopod with dactyl sexually dimorphic, longer, slenderer and more strongly curved in females than in males ( Fig. 10E, F ); propodal rasp with 1 row of rounded scales at least distally. Fifth pereopod propodal rasp extending to mid-length of segment. Uropods and telson markedly asymmetrical; telson ( Fig. 10J ) lacking transverse suture, posterior lobes separated by shallow cleft, terminal margin of lobes armed with long, often strongly curved corneous spines. Male lacking first gonopods; second pair of gonopods ( Fig. 10G–I ) weakly developed, asymmetrical, left usually 1-segmented or occasionally 2-segmented with short distal segment, right 1-segmented, rudimentary or absent. Female with vestigial second right pleopod.

Colouration. Unknown.

Habitat. Gastropod shells.

Distribution. Western Pacific, on the eastern coast of Australia, and the Philippines. Depth: 189–1150 m.

Remarks. Oncopagurus cidaris is one of eight species of Oncopagurus in which males lack first gonopods; the others are: O. haigae , O. oimos , O. orientalis , O. tuamotu , and four of the new species described herein, O. elevatus , O. rossanae , O., and O. brevis . Although these eight species share that condition, they differ markedly in a number of characters, primarily from the epistome, cephalic appendages, right chela, ambulatory legs, and telson. The absence of first gonopods (presumably through loss) is a condition that appears to be the result of evolutionary convergence in the Parapaguridae , as males of eight species of another genus, Paragiopagurus Lemaitre, 1996 , also lack first gonopods: P. acutus ( de Saint Laurent, 1972) , P. bicarinatus ( de Saint Laurent, 1972) , P. hirsutus ( de Saint Laurent, 1972) , P. hobbiti ( Macpherson, 1983) , P. ruticheles A. Milne-Edwards, 1891 , P. ventilatus Lemaitre, 2004 , P. trilineatus Lemaitre, 2013 , and P. orthotenes Lemaitre, 2013 .

As documented by Lemaitre (1996), the shape of the dactyl of the fourth pereopod is sexually dimorphic in Oncopagurus cidaris , with females having distinctly longer dactyls and more strongly curved (hook-like) than in males.

Oncopagurus conicus Lemaitre, 2006 Figs. 10K–S , 51

Oncopagurus conicus Lemaitre, 2006: 519 , figs 1–4 (type locality: New Caledonia, HALIPRO 1, sta C 858, 21°42'S, 166°41'E); McLaughlin et al., 2010: 39.

Type material. Holotype, New Caledonia, HALIPRO 1, sta C 858, 21°42'S, 166°41'E, 1000–1120 m, 20 March 1994: M 2.0 mm ( MNHN Pg. 7612).

Paratypes, New Caledonia, same sta as holotype: 2 F 2.0, 2.4 mm ( MNHN Pg. 7613); BIOGEOCAL, sta CP 214, 22°43'09'S, 166°27'19'E, 1590–1665 m, 9 April 1987: 1 M 2.1 mm, 1 F 1.8 mm, 1 ov F 2.1 mm ( NMNH Pg. 7614) .

Additional material. None.

Diagnosis. Shield ( Fig. 10K ) longer than broad; rostrum broadly rounded, weakly produced, with short mid-dorsal ridge; lateral projections subtriangular, terminating in small spine. Ocular peduncles more than half length of shield, diminishing in width distally, somewhat inflated ventroproximally, with longitudinal row of long setae dorsally, corneas reduced, subconical, usually ending sharply ( Fig. 10L ). Ocular acicles subtriangular, each terminating in strong spine. Antennular peduncle ( Fig. 10K ) exceeding distal margin of cornea by at least 0.2 length of penultimate segment. Antennal peduncle ( Fig. 10K ) exceeding distal margin of cornea by about 0.2 length of fifth segment; fourth segment unarmed; second segment with dorsolateral distal angle terminating in strong, simple spine, mesial margin with spine on dorsodistal angle; first segment with lateral face unarmed or with small spine; acicle not reaching tip of acute cornea, mesial margin armed with 2–5 small spines; flagellum slightly exceeding extended right cheliped, with setae <1–3 flagellar articles in length. Third maxilliped with crista dentata armed with about 9 teeth diminishing in strength distally. Right cheliped ( Fig. 10M, N ) relatively slender, not operculate, with moderately dense setae on dorsal surfaces of carpus and chela, fingers nearly straight; dactyl set at weakly oblique angle to longitudinal axis of palm; palm longer than broad, dorsal surface with scattered small spines or tubercles, lateral face rounded or sometimes with dorsolateral margin weakly delimited by row of small spines, mesial face rounded, dorsomesial margin delimited by row of small blunt or sharp spines, ventral surface with scattered small tubercles; carpus with dorsolateral margin rounded, dorsal surface with scattered small spines or tubercles. Left cheliped sometimes weakly calcified dorsomedially on merus and carpus; palm unarmed except for dorsomesial and dorsolateral setae; carpus unarmed except for dorsodistal spine and long setae dorsally. Ambulatory legs with dactyls ( Fig. 10O ) each having ventromesial row of 4–7 slender, corneous spinules; carpi unarmed except for small dorsodistal spine, and long setae dorsally. Anterior lobe of sternite XII (between second ambulatory legs) subsemicircular, setose, with distinct spine. Fourth pereopod propodal rasp ( Fig. 10P ) with 1 row of rounded scales at least distally. Fifth pereopod propodal rasp extending to mid-length of segment. Uropods and telson ( Fig. 10S ) symmetrical or nearly so; telson lacking transverse suture, posterior margin separated by shallow or obsolete U-shaped cleft into rounded projections, each armed with about 4–7 corneous spines, some often ventrally curved. Male with paired first and second gonopods ( Fig. 10Q, R ); first gonopod with weakly concave distal lobe; second gonopod with distal segment having row of short bristles on lateral margin medially, and long setae on distomesial face. Female with short, uniramous, 1-segmented second right pleopod.

Colouration. Unknown.

Habitat. Scaphopod shells.

Distribution. So far known only from the New Caledonia region. Depth: 1000–1665 m.

Remarks. This species and three other congeners, Oncopagurus minutus , and two new species, O. elongatus and O. petilus , have reduced or subconical corneas. In O. conicus , the corneas typically are slender or acute distally and often terminate sharply ( Fig. 10K, L ), whereas in O. minutus , O. elongatus , new species, and O. petilus , new species, the corneas are rounded distally ( Figs. 20B , 27B , 31A ). Oncopagurus conicus can be readily differentiated from those three species and all others in the genus, by the symmetrical (or nearly so) uropods and telson. Also, in O. conicus the right chela is not operculate, with the lateral face rounded or at most with a weakly defined dorsolateral margin; whereas in the other three species the chela is operculate, with a lateral face sharply defined by a row of spines.

Figures

Fig. 10. A–J, Oncopagurus cidaris Lemaitre, 1996, Queensland, Australia (QM W16596):A–E, G, H, J, paratype, male 2.9 mm; F, paratype, female 2.6 mm; I, paratype, male 2.7 mm. A, shield and cephalic appendages, dorsal; B, right cheliped, dorsal; C, chela of same, mesial; D, dactyl of left first ambulatory leg, mesial; E, F, propodus and dactyl of left fourth pereopod in male (E) and female (F), lateral; G, I, male left second gonopod, lateral; H, male right second gonopod; J, telson, dorsal. K–S, Oncopagurus conicus Lemaitre, 2006, holotype, male 2.0 mm, New Caledonia, (MNHN Pg 7612): K, shield and cephalic appendages, dorsal; L, right ocular peduncle, lateral; M, right cheliped, dorsal; N, chela of same, lateral; O, dactyl of left first ambulatory leg, mesial; P, propodus and dactyl of left fourth pereopod, lateral; Q, left first gonopod, mesial; R, left second gonopod, anterior; S, uropods and telson, dorsal. Scale bars = 2 mm (A–F); 0.5 mm (G–J); 0.5 mm (K, L, S); 1 mm (M, N, O); 0.2 mm (P–R). [Adapted from Lemaitre (1996, 2006)].

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

Fig. 20. Oncopagurus elongatus, new species: A, B, D–G, holotype, female 4.0 mm, Vanuatu, MUSORSTOM 8, sta CP 1080 (MNHN- IU-2013-5497); C, H, I, paratype, male 3.0 mm, French Polynesia, BENTHAUS, sta DW 2020 (MNHN-IU-2013-5508, ex MNHN Pg 6724). A, shield and cephalic appendages, dorsal; B, right ocular peduncle, lateral; C, anterior portion of shield and cephalic appendages, dorsal; D, anterior and posterior lobes of sternite XII (between second ambulatory legs); E, sternites XIII and XIV, and coxae of fourth and fifth pereopods, ventral; F, exopod of left uropod, dorsal; G, telson, dorsal; H, left first gonopod, mesial; I, left second gonopod, anterior. Scale bars = 1 mm (A, C); 0.5 mm (D, B, E–G); 0.25 mm (H, I).

Fig. 27. Oncopagurus minutus (Henderson, 1896): male 2.5 mm, New South Wales, Australia (AM P40409). A, shield and cephalic appendages, dorsal; B, right ocular peduncle, lateral; C, right cheliped, dorsal; D, chela of same mesial; E, dactyl of first ambulatory leg, mesial; F, propodus and dactyl of left fourth pereopod, lateral; G, telson, dorsal; H, left first gonopod, mesial; I, left second gonopod, anterior. Scale bars = 1 mm (A, C–E), 0.5 mm (B, F–I)). [Adapted from Lemaitre (1996)].

Fig. 31. Oncopagurus petilus, new species: holotype, male 4.6 mm, eastern Pacific, off Ecuador SEPBOP, R/V Anton Bruun: cruise 18B, sta 770 (USNM 1207983). A, shield and cephalic appendages, dorsal; B, right antennal peduncle, lateral; C, sternum and coxae of first to fifth pereopods, and anterior portion of pleon with first gonopods, ventral; D, exopod of left uropod, dorsal; E, telson, dorsal; F, left first gonopod, mesial; G, left second gonopod, anterior. Scale bars = 1 mm (A, C); 0.5 mm (B, E, F); 0.25 mm (D).