Munidopsis papanui, Schnabel & Bruce, 2006

Schnabel, Kareen E. & Bruce, Niel L., 2006, New records of Munidopsis (Crustacea: Anomura: Galatheidae) from New Zealand with description of two new species from a seamount and underwater canyon, Zootaxa 1172, pp. 49-67 : 59-65

Munidopsis papanui n. sp.

( Figs 4–6 )

Material examined

HOLOTYPE: ♂ (7.7 mm), Papanui Canyon , New Zealand, 45°51.40’ S, 171°01.00’E, 13 June 1973, 420 m, coll. PMBS, stn. Z15078 ( NMNZ CR. 10023) . PARATYPE: 1 ♀ (8.1 mm), same data as holotype ( NIWA 21140 ) .

Diagnosis

Dorsal surface densely covered with sparsely setose tubercles and serrated processes, deeply sculptured; cervical groove distinct; distinct paired processes in gastric and postcervical regions. Frontal margin with strong antennal process; anterolateral margin square; lateral margins with 3 blunt processes; posterior margin with transverse row of spines and serrations along entire margin. Rostrum triangular, slightly less than one­third length of remaining carapace. Abdominal tergites strongly sculptured; tergites 2 and 3 with strong blunt median process. Eyestalk not movable; with papillate, tuberculate processes mediodorsally and 1 lateroventral eye spine. Antennule cristate dorsolaterally; with 3 distal spines. Antenna article 3 with 3 blunt distal teeth. Cheliped elongate, 1.6 (female) to 2.0 (male) times as long as carapace; surface setose, spinose, and covered with tubercular processes; with row of spines along dorsal propodal margin. Walking legs not exceeding end of chelipeds, covered with tubercular processes; dactyli with 13–14 inclined setae along flexor margin. Pereopods 1–3 with epipods.

Description

Carapace: 1.3–1.4 [1.35] times as long as broad (including rostrum), moderately convex from side to side. Dorsal surface sparsely setose, strongly ornamented with tubercles and serrated processes. Cervical groove deep and distinct. Epigastric and postcervical regions each with pair of tuberculate processes. Frontal margin slightly oblique; antennal spine strong, lateral margins serrated. Anterolateral margin square, with small, blunt process directed anteriorly. Lateral margins subparallel, slightly wider posteriorly, with 3 spines (or processes) behind anterolateral spine and strongly crenulated, first lateral spine largest (excluding anterolateral spine). Posterior margin with 12 spines and intermediate serration. Rostrum triangular, horizontal, 0.3 times length of remaining carapace; dorsal surface moderately carinate, lateral margin with fine lateral serration along posterior half and posteriorly constricted, apex blunt, dorsal surface moderately carinate. Pterygostomian flap lateral surface granulate, anterior margin produced into a small spine.

Sternum: sternite 3 3.3–3.6 [3.3] times as broad as long; anterior margin bilobed and serrated, without distinct central notch; lateral margins rounded, anterolaterally produced to small tooth; surface slightly granulose. Sternite 4 2.1 times as wide as sternite 3; anterior margin broadly convex; anterior midline shallowly grooved; surface with rows of setae. Ridges demarcating sternites 4–7 with rows of setae; surfaces with submedian row of setae.

Abdomen: tergites covered with granules (posterior tergites pitted); tergites 2–4 with 2 elevated ridges separated by median transverse groove; tergites 2 and 3 with weak lateral and strong central blunt processes on anterior transverse ridges; tergites 4–6 unarmed, pitted and sparsely setose. Telson 1.4–1.7 [1.4] times as broad as long, composed of 8 plates; lateral margin with a row of plumose setae and small spines; uropodal endopods with short rows of spines on surface; lateral margins with row of spines and plumose setae.

Eyes: immobile, papillate and tuberculate mediodorsally, sparsely setose, with lateroventral eye spine. Cornea subglobular, with small spine between eye and antennal peduncle.

Antennule: distodorsal spine shorter than distolateral spine, distomesial spine small, with cristate row of several spines dorsolaterally; mesial margin crenulated; lateral margin sparsely dentate; surface granulate with scattered small spines.

Antenna: article 1 with long spine on distomesial margin (reaching end of article 2), distolateral margin produced to blunt tooth (surface of article 1 with scattered small spines); article 2 with blunt distomesial and distolateral tooth; article 3 with blunt mesial, lateral and dorsal processes distally.

Maxilliped 3: surface granulose; ischium with small distal spine on extensor margin and with distal spine on flexor margin, 18–21 [20–21] teeth on mesial ridge; merus, extensor margin with distal spine and with crenulate lateral margin, flexor margin with 3 strong teeth, proximal largest, and 1 small distal spine; carpus extensor margin with 3–4 teeth; propodus and dactylus unarmed.

Pereopod 1 (cheliped): elongate, sexually dimorphic, 2.0–1.9 (left) [2.0] and 1.6–1.9 (right) [1.9] times as long as carapace (including rostrum), surface setose, spinose, and tuberculate. Ischium with dorsal distal spine. Merus surface covered with setiferous tubercles and 5 rows of spines or blunt processes, with 4 distal spines (2 of which blunt). Carpus surface spinose, with 3 longitudinal rows of spines, and 5 distal spines or blunt processes; carpus 0.3–0.4 [0.4] times as long as palm. Propodal palm sexually dimorphic, 2.7–3.7 [2.7–3.0] times as long as high, spinose and setose, with distinct row of spines on dorsal margin. Dactylus 0.5 times as long as propodus; opposable margins not gaping (slightly gaping in male right cheliped), occlusal margin denticulate.

Pereopods 2–4: surface slightly setose; P2 reaching anteriorly to proximal quarter of propodus of pereopod 1. Merus, dorsal margin with row of blunt spines and processes (from 8 [P2] to 3 [P4] spines including a blunt distal process); ventral margin with distal spine and row of tubercular processes; 1.3–0.8 [1.2–0.8] times as long as propodus (merus shortening from P2 to P4). Carpus, dorsal margin with tubercular processes, with 4 spines on dorsal crest (includes distal), with 1 blunt distal spine on ventral margin, with dorsolateral ridge of tubercles. Propodus 1.3–1.6 [1.5–1.6] times as long as dactylus; extensor margin crenulate (surface with scattered minute spines). Dactylus straight, flexor margin with inclined setae along the distal ¾, with 13–14 [13] inclined setae along flexor margin (excluding distal spine). Pereopods 2–4 decreasing in length (and spination) posteriorly.

Epipods: present on pereopods 1–3, absent from pereopod 4.

Colour Label in original vial contains note on coloration as follows: ‘uniform orange, excluding pale barred legs’.

Variation

The female is slightly larger than the male but the overall proportions and spination are constant except for an apparent sexual dimorphism in the size of the chelipeds and their handedness. The right propodus of the male is more massive than the left (ratios length–width 2.7 [right] and 3.0 [left]) whereas the left propodus is more massive in the female specimen (3.7 [right] and 2.9 [left]) ( Fig. 6 ). The left cheliped of the female is very similar to the right cheliped of the male though the right cheliped of the female is significantly reduced in size, despite being fully developed and undamaged.

Remarks

Munidopsis papanui n. sp. is distinguished by the spinose and tuberculate processes on the dorsal surfaces and appendages, the ocular peduncle with papillate mediodorsal processes peduncle and with ventral eye spine, the dorsolaterally cristate antennule and, most distinctly, the presence of the strong blunt median processes on abdominal tergites 2 and 3.

Munidopsis papanui n. sp. is most similar to the group of tuberculate species, comprising M. proales Ahyong & Poore, 2004 , M. tasmaniae Ahyong & Poore, 2004 , M. sonne Baba, 1995 and M. taurulus Ortmann, 1892 (redescription by Baba [2001]). However, M. papanui can easily be distinguished from all these by the strong blunt median process on the second and third abdominal tergites.

Munidopsis papanui is similar to M. sonne in that it shares the dorsally cristate antennule (absent in the other three species), but can be distinguished by the absence of papillate processes distally on the ocular peduncle and more distinctly spinose lateral margin of the carapace.

Munidopsis proales and M. taurulus have a much more slender cheliped compared to that of M. papanui but similarities with M. taurulus include the spinose posterior border of the carapace and the third antennal article with three spines. Munidopsis proales can further be distinguished from M. papanui by the smooth abdomen, the posterior margin of the carapace only with rugose squamae along the ridge, and by a pair of more pronounced epigastric spines.

Munidopsis papanui differs from M. tasmaniae most distinctly by the ornamented abdominal tergites, less pronounced epigastric processes and mesial row of spines on the palm of the cheliped.

The size of the two specimens of M. papanui is also smaller (maximum 8.1 mm) than M. tasmaniae (15.2–17.7 mm) and M. sonne (10.5–10.8 mm) but is comparable to that of M. proales (9.1 mm) and M. taurulus (7.3–11.7 mm).

Armed abdominal tergites are common in Munidopsis , with M. taurulus for example bearing a number of compressed spines on tergites 2 and 3. Munidopsis curvirostra Whiteaves, 1874 , also known from the Lord Howe Ridge, has a single median spine on tergites 2 to 4 but these are smaller and more acute than those present in M. papanui n. sp. Munidopsis papanui and the North Atlantic species M. parfaiti ( Filhol, 1885) share a more notable similarity in their dorsal abdominal armature with the latter bearing blunt median processes on abdominal segments 2 to 4 (only segments 2 and 3 in M. papanui , segment 4 bearing only two transverse ridges). Munidopsis parfaiti otherwise differs greatly from M. papanui in the shape and armature of the carapace and eyes and the abdominal spines are more acute (see Macpherson & Segonzac 2005).

The male holotype has two unidentified epizoids attached, one small circular growth on the propodus of the left cheliped and one elongate attachment to the apex of the right ocular peduncle ( Fig. 4 ).

Distribution Known only from the type locality, Papanui Canyon on the Otago shelf, southeastern coast of South Island, New Zealand ( Fig. 1 ); depth of 420 metres.

Etymology

Named for the type locality. Papanui is also a Māori word for palm of a hand, alluding to the apparent sexual dimorphism and lateral asymmetry of the cheliped palm (noun in apposition).

Figures

FIGURE 1. Station records of the currently known species of Munidopsis (solid symbols) and new records (open symbols) around New Zealand. 250 m and 2000 m bathymetric contours are shown.

FIGURE 4. Munidopsis papanui n. sp., holotype, ♂, NMNZ CR. 10023. A, carapace and abdomen, dorsal; B, carapace and abdomen, lateral; C, sternal plastron; D, left cheliped, dorsal; E, right cheliped, dorsal, setae omitted; F–H, right pereopods 2–4, lateral; I, dactylus of right pereopod 2, lateral; J, posterior part of abdomen with uropods and telson. Scale: 2 mm (scale 1 for A–H and J; scale 2 for I).

FIGURE 5. Munidopsis papanui n. sp., holotype, ♂, NMNZ CR. 10023: A, right antennule, ventral; B, right antennule, lateral; C, right antennal peduncle, ventral; D, right third maxilliped, lateral. Scale: 2 mm.

FIGURE 6. Munidopsis papanui n. sp., A, holotype, ♂, NMNZ CR. 10023, dorsal view. B, paratype, ♀ NIWA 21140, dorsal view.