Enoplometopus gracilipes (de Saint Laurent, 1988 )

Poupin, Joseph, 2003, Reef lobsters Enoplometopus A. Milne Edwards, 1862 from French Polynesia, with a brief revision of the genus (Crustacea, Decapoda, Enoplometopidae), Zoosystema 25 (4), pp. 643-664 : 646-652

Enoplometopus gracilipes (de Saint Laurent, 1988)

( Figs 4 ; 5 )

Hoplometopus gracilipes de Saint Laurent, 1988: 62 (type locality: Moruroa atoll, Tuamotu; paratype from Loyalty Islands).

Hoplometopus gracilipes – Poupin et al. 1990: 16 ( French Polynesia). — Poupin & Richer de Forges 1991: 211 ( French Polynesia). — Poupin 1996a: 14 ( French Polynesia); 1996b: 95 (checklist).

Enoplometopus gracilipes – Chan 1998: 998 (western Pacific). — Chan & Yu 1998: 190 (key).

? Enoplometopus gracilipes (provisional determination according to illustration only; see Remarks) – Anonymous 1973: unnumbered plate ( Japan). — Miyake 1983: 106 ( Japan).

MATERIAL EXAMINED. — French Polynesia. Australs Islands , Rurutu, Frv Marara , stn 147, 22°27.3’S, 151°23.1’W, trap 280 m, 9.III.1989, 5 ♂♂ cl 52- 60 mm, bl 161-182 mm, 2 ♀♀ cl 50-54 mm, bl 154-160 mm ( MNHN As 548, in two vials) ; stn 423, 22°29.3’S, 151°21.6’W, trap 80 m, 10.VIII.1991, 1 ♂ cl 40 mm, bl 117 mm, 1 ♀ cl 42 mm, bl 121 mm ( MNHN As 626). — Tuamotu Islands , Moruroa, Frv Marara , stn unknown, trap 250-300 m, 1987, 1 ♂ holotype cl 53 mm, bl 160 mm ( MNHN As 544) ; Frv Marara , stn 210, 21°46.9’S, 138°55.4’W, trap 210 m, 30.XI.1989, 3 ♂♂ cl 46-53 mm, bl 139-159 mm ( MNHN As 622) ; stn 207, 21°46.8’S, 138°52.1’W, trap 200 m, 28.XI.1989, 1 ♂ cl 43 mm, bl 134 mm ( MNHN As 623) .

New Caledonia. Loyalty Islands, stn PR1-R3, trap 200 m, VI.1977, coll. A. Intès, 1 ♂ paratype cl 44 mm, bl 133 mm ( MNHN As 531).

DISTRIBUTION. — West and central Pacific:? Japan, New Caledonia (Loyalty Islands), French Polynesia ( Austral Islands : Rimatara , Rurutu , Tubai ; Society Islands : Bora Bora , Tahiti , Tupaï ; Tuamotu Islands : Fangataufa , Moruroa ). Depths : 80-300 m, usually deeper than 100 m. On hard bottoms.

DESCRIPTION

Rostrum slightly overreaching spine of scaphocerite, triangular in dorsal view, dorsally depressed, with four spines on lateral margin. Carapace bearing fine tomentum on gastric area, armed with five median, two postcervical, one intermediate, one supraocular, and three lateral spines; lateral face with one branchiostegal plus two to four additional small spines ( Fig. 5A ).

Antennular peduncle with basal segment as long as median and distal segments together; distal segment with two terminal flagella, inner longer than outer. Basal segment of antennal peduncle with antennal gland on ventral face and seven or eight spines on anterior margin, inner and outer ones large; second segment with one distolateral spine; third segment with rounded distal process armed with one subdistal spine (occasionally missing); fourth and fifth segments subequal and unarmed; flagellum long, overreaching tip of chelipeds. Outer margin of antennal scaphocerite straight with one strong distal spine; inner margin distally curved, furnished with plumose setae; upper face with deep groove, parallel to outer margin.

Third maxilliped almost reaching to distal margin of carpus of cheliped. Basis with one distoventral spine. Ischium triangular in cross section, with one strong distodorsal spine; ventral outer margin furnished with long setae and armed with one or two distal spines; ventral inner margin with comblike crista dentata made of about 20 spines of irregular size; merus triangular in cross section, with one distodorsal spine; ventral outer margin with three to six spines on distal two thirds, increasing in size anteriorly; ventral inner margin with setae. Carpus with one distolateral spine. Propodus and dactyl with ventral faces flattened, bearing long setae on margins.

Cheliped much longer than ambulatory legs. Ischium compressed, with one distodorsal spine; ventral margin with five to seven spines, increasing in size anteriorly. Merus compressed; dorsal margin with main row of six or seven spines and short row of two or three outer spines, distally; anterior margin with two dorsal spines, one spine on inner and outer articular condyles, and one ventral spine; ventral face with eight or nine spines on outer margin and six or seven spines on inner margin; Carpus with four spines on dorsal face; anterior margin with four dorsal spines, one or two small outer spines, one strong inner spine and one strong ventral spine. Chela very long, 5.6-7.6 times as long as wide (average 6.5); palm ovate in cross section, smooth on upper and lower faces; outer margin with nine to 12 spines; inner margin with six to nine spines. Fingers long and slender, 0.5 times as long as chela, with sharp, inwardly curved tips; cutting edges straight, with six to eight main teeth and minute denticulation in between; outer margins unarmed, with few sparse setae ( Fig. 5C ).

Second pereopod slender, subchelate, reaching to proximal fourth of chela, rounded in cross section; upper and lower margins with few long setae. Merus with one distolateral spine. Carpus 0.4 times as long as merus, armed with one distoventral spine. Propodus as long as merus, with distoventral process bearing five to eight tiny spines on upper margin, and two mobile spines distally. Dactyl short, 0.20 times as long as propodus, terminated by strong distal claw; lower margin armed with 25-30 tiny spines plus two subdistal corneous spines; distodorsal margin with one mobile spine; distal outer face with one mobile spine ( Fig. 5D ). Third pereopod with one distoventral spine on merus. Carpus unarmed. Propodus with distoventral process reduced, bearing two or three tiny spines on dorsal margin and two mobile spines distally. Dactyl with strong terminal claw, three or four mobile spines disposed on outer and inner faces; ventral margin with 10-13 tiny spines and one corneous spine distally. Fourth pereopod similar to P3; distoventral process of propodus reduced, with three or four mobile spines distally. Pereopod 5 shortest, without terminal pincer. Merus and carpus without spines. Propodus with six to eight small spines at distoventral angle. Dactyl with five or six mobile spines disposed on inner and outer faces; proximal half with ventral process armed with row of minute spines.

Thoracic sternite V of male with two anterior and two posterior spines; lateral margin with zero or one spine. Sternite VI with two anterior and two posterior spines; anterolateral margin with three to six tubercles or spines; posterolateral margin with zero or one spine. Sternite VII as a deep V-shaped hollow, with two anterior spines or granules and two stronger posterior spines, forwardly curved; anterolateral margin with three or four spines or tubercles; posterolateral margin with one or two spines or tubercles. In female, seminal receptacle on sternite VII with median slit covered by transverse setae.

Abdomen smooth, with few long setae on tergites V-VI. Pleuron of abdominal somite I narrow, overlapped by pleuron of somite II. Pleura of somites II-V with sharp tooth, posteriorly curved ( Fig. 5B ). Pleuron of somite VI with blunt tooth. Posterior margin of tergite VI unarmed ( Fig. 5E ). Male first pleopod as an uniramous rigid blade, indented distally as illustrated on Figure 5E . Second pleopod biramous; endopod with two appendices (interna and masculina). Pleopods 3-5 biramous; endopod and exopod leaflike, furnished with long setae on margins. Female first pleopod uniramous, long and slender. Pleopods 2-5 biramous; endopod and exopod similar to male pleopods 3-5, except for rounded basal process furnished with few long setae on inner margin of endopod.

Basal segment of uropod segment with two dorsal spines and one ventral spine on distal margin; endopod with one distolateral spine; exopod with spiny diaeresis on distal fourth; lateral edge of diaeresis with one dorsal fixed spine and one ventral mobile spine. Telson subrectangular, slightly longer than wide; lateral margin with two spines of similar size; distolateral angle with two spines, inner one longer ( Fig. 5E ).

Coloration ( Fig. 4 )

Ground color of body pale orange with tip of spines white. Carapace, abdomen, and telson with numerous dark orange patches, grouped by sets of two to four. Cheliped pale orange with faint darker bands. Ambulatory legs with alternated white and orange bands.

REMARKS

In 16 specimens examined a few unusual armaments have been observed. The lateral margin of rostrum can have three to five spines, instead of the usual four. There are two intermediate spines on the carapace, instead of one, in a female cl 42 mm ( MNHN As 626). The distoventral spine of carpus of second pereopod was absent on the smallest specimen examined (male cl 40 mm). Spines were also occasionally missing on inner and outer faces of dactyls of ambulatory legs.

Enoplometopus gracilipes is morphologically related to E. holthuisi Gordon, 1968 and E. voigtmanni Türkay, 1989 . The three species have in common the same disposition of spines on the carapace, a similar shape of pleura of abdominal somites II-V, and a similar long and slender chela, smooth on the upper and lower faces of palm, with fingers as long as the palm. Enoplometopus gracilipes is at once distinguished from the two other species by its coloration, being the only one with spots on the carapace whereas the lateral face of the carapace has a large white circle in E. holthuisi , and a network of streaks in E. voigtmanni . In the absence of coloration E. gracilipes can be distinguished by examination of the posterior margin of the sixth abdominal tergite, which has no spines, while it has two short lateral spines in the two other species (cf. Fig. 5E with Fig. 7E ). Although shape of male first pleopod is still not known in E. voigtmanni , it is also obviously different between E. gracilipes and E. holthuisi (cf. Fig. 5F with Fig. 7F ). Finally, E. gracilipes is a deep-water species, mostly collected at depths greater than 100 m, while E. holthuisi and E. voigtmanni are only known at depths less than 100 m.

Illustrations of an undetermined specimen have been published in two Japanese books ( Anonymous 1973; Miyake 1983). According to its coloration, this unique specimen could reasonably belong to E. gracilipes . However, this provisional determination must be confirmed when more specimens are available from Japan.

Figures

FIG. 4. — Enoplometopus gracilipes de Saint Laurent, 1988, Tuamotu Islands, Moruroa atoll, 200 m; A, lateral view; B, dorsal view.

FIG. 5. — Enoplometopus gracilipes de Saint Laurent, 1988, holotype ♂ cl 53 mm, Tuamotu Islands (MNHN As 544); A, carapace, dorsal view; B, abdomen, lateral view; C, left chela, dorsal view; D, dactyl and distal part of propodus of right second pereopod, outer view; E, posterior margin of tergite 6 and telson, dorsal view; F, right first pleopod, outer view (setae omitted). Scale bars: 5 mm.

FIG. 7. — Enoplometopus holthuisi Gordon, 1968, ♂ cl 28 mm, Austral Islands (MNHN As 624); A, carapace, dorsal view; B, abdomen, lateral view; C, left chela, dorsal view; D, dactyl and distal part of propodus of left second pereopod, outer view; E, posterior margin of tergite 6 and telson, dorsal view; F, right first pleopod, outer view, ♀ holotype cl 33 mm, Banda Islands (ZMA De 101.265); G, left chela dorsal view (setae omitted). Scale bars: 5 mm.