Munidopsis bairdii ( Smith, 1884 )

Macpherson, Enrique & Segonzac, Michel, 2005, Species of the genus Munidopsis (Crustacea, Decapoda, Galatheidae) from the deep Atlantic Ocean, including cold-seep and hydrothermal vent areas, Zootaxa 1095 (1), pp. 1-60 : 17-19

Munidopsis bairdii ( Smith, 1884) ( Fig. 4 )

Galacantha bairdii Smith, 1884: 356 .

Munidopsis bairdii .— Baba, 2005: 285 (complete synonymy and references).

Material examined. NE Atlantic, NORATLANTE, Stn 16­B01, 55º07.7’N, 15º11.2’W, 2220 m, 10.08.1969: 2 males 10.2–20.0 mm. N Atlantic, BIACORES, Stn 252, 47º35.5’N, 08º47’W, 2640 m, 18.11.1971: 1 male 22.2 mm. Bay of Biscay, BIOGAS 6, Stn CP 10, 47º30’N, 09º04’W, 2878 m, 21.10.1974: 1 male, 1 juv. 8.7 mm. Off Ireland , INCAL, Stn CP 04, 56º33.2’N, 11º11.3’W, 2483 m, 17.07.1976: 3 males 10.9–23.8 mm, 1 female 11.9 mm.— Stn CP 08, 50º14.7’N, 13º13.5’W, 2644 m, 27.07.1976: 2 males 18.6–20.9 mm. NW Atlantic, MAR­ECO, Stn 72 (Lstn 386), 53º10’N, 35º53’W, 2534 m, 27.07.2004: 3 males 23.7–26.0 mm, 1 ovig. female 31.5 mm, 6 females 10.5–31.4 mm .

Diagnosis. Body covered with fine. stiff setae. Carapace moderately granulose on anterior half, bearing short granulate ridges on posterior half. Gastric region rather well defined, convex, bearing 3 pairs of spines: median pair of spines smaller than other pairs. Cervical groove distinct. Cardiac region with anterior ridge preceded by distinct groove, bearing pair of spines followed by 1­2 spines in midline. Posterior margin with 4–10 spines and elevated ridge. Front margin strongly oblique; antennal spine absent. Lateral margins slightly convex, each with 4 spines: first slender, present at anterolateral angle, directed anterolaterad, second strong, directed more laterad than first, third and forth short. Rostrum curving dorsad, dorsally moderately carinate, bearing 2–4 lateral teeth. Abdomen unarmed; segment 6 having well­developed posterolateral lobes distinctly overreaching nearly transverse posteromedian margin. Telson divided into 8 plates. Ocular peduncles slender, slightly movable, with well­produced, anterolaterally directed eye­spine. Antennular basal article with strong distolateral and distodorsal spines and 2 small disto­ mesial spines. Article 1 of antennal peduncle with distomesial and distolateral spines, both short, somewhat depressed, article 2 with strong distolateral and small distomesial spines, article 3 with small distolateral, distomesial and distodorsal spines. Mxp 3 merus with 2–4 spines on flexor margin and 1 distinct spine on extensor distal margin. Pereopods covered with short setae nearly perpendicular to surface. P1 merus with dorsal and lateral marginal rows of spines, and some acute terminal spines; carpus with several terminal and mesial marginal spines; palm barely as long as fingers, mesial margin with 2 or 3 spines; fingers distally fitting each other with few intermeshing teeth, distolateral margin of fixed finger smooth, not serrate. P2–4 subcylindrical; meri spinose along dorsal and ventral margins; carpi with spines on dorsal margin; each dactylus two­thirds as long as propodus, gently curving, flexor margin with 9–11 distinct teeth, each supporting stiff seta, ultimate tooth more remote from end of article than from penultimate tooth. First walking leg overreaching end of chelipeds. Epipod absent from pereiopods.

Remarks. Munidopsis bairdii belongs to the group of species having the carapace with a longitudinal row of submedian spines, the posterior­most transverse ridge with spines, the rostrum with lateral spines, the abdomen unarmed, the ocular peduncle movable and short relative to length, the eye­spine directed straight forward, the fixed finger of the chelipeds without a denticulate carina on the distolateral margin, the first walking leg overreaching the cheliped, the dactylus of the first walking leg three­quarters as long as the propodus, and no epipods on the pereiopods.

Distribution. Northwest Atlantic, off Delaware Bay, 2738 m (type locality, Smith 1884), Gulf of Panama, 3243 m ( Faxon 1895), Ecuador, 2150 m (Khodkina 1975), Baja California, 1986–2008 m ( Luke 1977), (off Oregon, 2377­2940 m ( Ambler 1980), off New England, Middle Atlantic Bight, 2125–2933 m ( Wenner 1982), Bay of Biscay, 3992–4260 m (de Saint­Laurent 1985). The present material was collected from the northeastern Atlantic (off British Isles, 55º07’N) to Bay of Biscay (47º30’S) between 2220 and 2878 m.

Figures

FIGURE 4. Munidopsis bairdii (Smith, 1884), male (20.0 mm), NE Atlantic, NORATLANTE, Stn 16­B01. A, carapace, dorsal. B, posterior part of sixth abdominal segment and telson. C, anterior part of sternal plastron. D, endopod of right third maxilliped, lateral. E, right cheliped, lateral. F, right second pereiopod, lateral. Scale: A–E, F = 4 mm, B–D = 2 mm.