Munidopsis sculpo, Schnabel, Kareen E. & Ahyong, Shane T., 2015

Schnabel, Kareen E. & Ahyong, Shane T., 2015, Two new species of Munidopsis (Crustacea: Anomura: Munidopsidae) from the Kermadec and Louisville ridge systems off New Zealand, Zootaxa 3995 (1), pp. 241-251 : 246-249

Munidopsis sculpo sp. nov.

( FigS 3–4 )

Material examined. Holotype - female ( NIWA 94044), cl 12.8 mm, pcl 9.0 mm, Forde Seamount, Louisville Ridge, New Zealand, 35°22.06–28.16’S, 170°20.78–20.77’E, 8 February 2014, 1175– 1280 m, stn. TAN1402/10.

Paratype - male ( NIWA 94030) (rostrum broken), pcl 6.5 mm, Forde Seamount, Louisville Ridge, New Zealand, 35°21.20–21.30’S, 170°22.24–22.10’E, 8 February 2014, 1154– 1270 m, stn. TAN1402/8.

Diagnosis. Entire body densely tuberculate or granulate. Frontal margin transverse. Carapace gastric region with large longitudinal median process; paired postcervical processes more densely furnished with tubercles than remaining carapace; cardiac region with large process; lateral margin with two large tuberculate processes posterior to anterolateral spine; posterior margin with upturned ridge with median notch. Rostrum triangular, slightly constricted proximally, without spines. Abdominal tergites 2−4 with large rounded median projection. Eyestalk immovable, eye-spine absent, cornea oval. Antennule dorsolaterally cristate. Pereopod 2 nearly reaching end of pereopod 1. Pereopods 2−4 propodi of uniform width; dactylus with eight or nine movable spines along entire length. Pereopods 1−3 with epipods.

Description. Carapace: Moderately convex in cross section; length including rostrum, 1.6 times as long as wide (pcl 1.1 times width); densely covered; densely covered with tubercles which are distally serrated, dorsoventrally flattened and curved anteriorly, some constricted basally giving them a pedunculate appearance.

Rostrum 0.4 pcl, triangular, slightly constricted proximally, densely covered in tubercles, otherwise unarmed; not deflected. Frontal margin transverse; antennal spine present. Lateral margins convex, with three blunt, swollen tuberculate processes, one at anterolateral angle, and one each on anterior and posterior branchial regions. Carapace regions well defined; cervical groove distinct; strong upright processes in gastric, postcervical and cardiac region as follows: a strongly convex narrow longitudinal ridge spanning entire length of gastric region; a blunt thorn-shaped process at centre of cardiac region, higher than gastric ridge; a pair of postcervical processes, anteriorly furnished with an arrow-shaped, particularly dense cluster of tubercles, posteriorly with a small diamond-shaped patch of smooth cuticle. Posterior ridge medially bilobed, preceded by small transverse area of smooth cuticle. Pterygostomian flap narrow, surface densely granulate; anterior margin rounded.

Sternum: 1.1 times as wide as long. Sternite 3 lateral margin subacute; anterior margin rounded, irregular; with shallow central notch; surface smooth. Sternite 4 2.5 times as wide as sternite 3; anterior margin slightly convex, densely furnished with granules; anterior half densely covered with granules. Anterior margin of sternite 5 granulate near centre line; remaining sternites smooth, unarmed.

Abdomen: tergites 2–4 each with strong rounded median process on elevated transverse ridge. Area anterior to median ridges smooth cuticle; remaining tergites densely covered with tubercles. Telson 1.2 times as broad as long, composed of eight large plates (the holotype has a pair of additional tiny plates bordering the central plate posteriorly, absent in the paratype); surfaces granular.

Eyes: immobile; peduncle granular, eye spines absent. Cornea oval, about 0.6 times as wide as peduncle.

Antennule: surface tuberculate; distolateral spines well developed, distinctly cristate; strongly cristate dorsolateral process; lateral margin slightly swollen.

Antenna: surface tuberculate. Article 1 unarmed. Article 2 with short blunt distolateral spine. Articles 3–4 unarmed.

Maxilliped 3: surface strongly tuberculate, sparsely setose. Basis with 3 or 4 irregular spines. Ischium with blunt distal spine on both extensor and flexor margins; crista dentata entirely and uniformly furnished with 17–20 triangular teeth (18–20 for holotype and 17 or 18 for paratype). Merus extensor margin with row of tubercles, with distal blunt spine; flexor margin tuberculate but with two prominent spines and a small blunt distal spine. Carpus, propodus and dactylus strongly tuberculate, otherwise unarmed.

Pereopod 1 (cheliped): stout, slightly shorter than carapace (including rostrum); surface entirely covered with tubercles, with only a few setae along distal tips of fingers. Ischium with small distodorsal spine. Merus with prominent distomesial spine and small distolateral spine. Carpus 0.8 times as long as palm of propodus, no distinct distal spines. Propodal palm 1.7 times as long as high. Dactylus 0.9 times as long as palm; both fingers unarmed; opposable margins not gaping, occlusal margins denticulate; apices with interlocking teeth.

Pereopods 2–4: surfaces strongly tuberculate, a few scattered setae. Pereopod 2 nearly reaching end of pereopod 1. Pereopods 2–4 meri slightly decreasing in length posteriorly with pereopod 4 merus 0.8 times as long as that of pereopod 2; pereopod 2 merus subequal in length to propodus; pereopod 3–4 meri approximately 0.8 times length of propodi; pereopod 2–4 meri and carpi dorsodistally with pronounced clusters of tubercles. Propodi 7 times as long as wide with a minute single movable distal flexor spine adjacent to a terminal tubercle. Dactyli straight, 0.4–0.5 times as long as propodi; flexor margins with eight or nine small movable spines along entire length (excluding corneous spine at tip).

Epipods: present on pereopods 1–3.

Colour in life. Anterior portion of body (anterior two-thirds of carapace, the chelipeds and anterior margins of the walking legs) deep orange, fading to a pale white in posterior portion of body; tips of rostrum and anterolateral spines, the median branchial prominence and cardiac grooves pale; ocular peduncles pale orange.

Remarks. The type material contains the female holotype and a smaller male paratype. The male is considerably damaged with the anterior portion of the carapace, the eyes, rostrum and chelipeds missing. However, the sculpturing and ornamentation of the remaining carapace, abdomen and walking legs clearly match the characteristics of this new species and conform to the morphology of the holotype specimen.

Munidopsis sculpo sp. nov. most closely resembles the group of species within the genus sharing a strongly tuberculate or rugose carapace. This includes M. sonne Baba, 1995 , M. papanui Schnabel & Bruce, 2006 and M. bractea Ahyong, 2007 with which it also shares the distinctly dorsolaterally cristate antennule. Munidopsis sculpo can, however, be distinguished from all other species of Munidopsis by the combination of the distinct longitudinal median convex ridge that spans the entire gastric region, the strong cardiac process and a large blunt median processes each on abdominal tergites 2–4.

Munidopsis sculpo was taken at two stations on the flanks of Forde Seamount on the Louisville Ridge ( Fig. 1 ) between 1154–1280 m depth. The substrate in the immediate area is described by Clark et al. (in press) as a mix of bedrock ledges and outcrops with sand overlay and patches of coral rubble.

Distribution. Known only from Forde Seamount on the Louisville Ridge; 1154–1280 m.

Etymology. Sculpo is the first person singular of the Latin verb ‘to carve, chisel, engrave’, with reference to the elaborately sculptured carapace and abdomen; used here as a noun in apposition.

Figures

FIGURE 1. Collection localities of Munidopsis bamberi sp. nov. (round inner circle) in the Havre Trough and M. sculpo sp. nov. (crossed inner circle) on the Louisville Ridge.

FIGURE 3. Munidopsis sculpo sp. nov., holotype female, cl 12.8 mm (NIWA 94044). A, cephalothorax and abdomen, B, cephalothorax and abdomen, right lateral view.

FIGURE 4. Munidopsis sculpo sp. nov., holotype female, cl 12.8 mm (NIWA 94044). A, pterygostomian flap, right lateral view; B, sternal plastron; C, right ocular peduncle, eye spine and antennal peduncle, dorsal view; D, left basal antennular segment, antenna and anterior margin of the pterygostomian flap, ventral view; E, right basal antennular segment, lateral view; F, left maxilliped 3; G, left crista dentata; H, telson; I, left cheliped, dorsal view; J, right cheliped fingers, mesial view; K – M, right pereopods 2 – 4, setae omitted. Scale bars: 2.0 mm for A – D, G, H, J – L; 3.0 mm for E – M. Inset: detail of tubercles covering body and appendages, left epigastric region of carapace.