Munida tangaroa, Ahyong, Shane T., 2007

Ahyong, Shane T., 2007, Decapod Crustacea collected by the NORFANZ Expedition: Galatheidae and Polychelidae, Zootaxa 1593, pp. 1-54 : 38-41

Munida tangaroa sp. nov.

( Fig. 14 E, 19)

Type material. Holotype: AM P73023, ovigerous female (9.8 mm), W of Norfolk Island, 28°51.21’S, 167°42.53’E, 690–812 m, TAN0308/29, 15 May 2003. Paratypes: AM P75441, 1 male (10.3 mm), 1 female (8.5 mm), W of Norfolk Island, 28°51.21’S, 167°42.53’E, 690–812 m, TAN0308/29, 15 May 2003; NIWA 28070, 1 ovigerous female (14.1 mm), W of Norfolk Island, 28°51.21’S, 167°42.53’E, 690–812 m, TAN0308/ 29 #008, 15 May 2003; NMNZ, 1 female (12.2 mm), W of Norfolk Island, 28°51.21’S, 167°42.53’E, 690– 812 m, TAN0308/29 #007, 15 May 2003.

Diagnosis. Carapace margins with 5 spines posterior to cervical groove; anterior branchial and postcervical spine present. Rostrum spiniform. Sternite 4 with broadly convex anterior margin. Sternites 5–7 smooth.

Abdominal tergite 2 with row of spines along anterior ridge; tergite 3 unarmed. Maximum corneal diameter half basal distance between anterolateral spines. Antennular basal segment with distolateral spine longer than mesial spine; ventral surface unarmed. Antennal basal segment mesial spine not reaching beyond segment 2; segment 2 with distomesial spine reaching to about midlength of segment 4. Maxilliped 3 merus extensor margin unarmed. Cheliped about 1.5 times carapace length; carpus 1.8 times long as high; pollex with strong spine on ventral proximal margin. Pereopod 2–4 dactylus with distalmost flexor spine at base of unguis.

Description. Carapace: Transverse ridges well spaced, generally entire; gastric and cardiac regions with several short striae; cervical groove distinct; with pair of distinct epigastric spines behind supraocular spines, flanked mesially and laterally by small spine; with 1 parahepatic, 1 anterior branchial and 1 postcervical spine. Frontal margins sloping posteriorly. Rostrum spiniform, horizontal, about three times as long as supraocular spines and almost half remaining carapace length. Supraocular spines subparallel. Anterolateral spine situated at anterolateral angle, slightly divergent, not extending to base of sinus between rostrum and supraocular spine. Margins of carapace anterior to cervical groove with 2 spines (including anterolateral); with 5 spines posterior to cervical groove.

Sternum: Sternite 3 broadly subquadrate; anterior margin sinuous. Sternite 4 with pair of short striae, otherwise smooth; anterior margin broadly convex. Sternites 5–7 smooth. Ridges demarcating sternites smooth.

Abdomen: Tergite 2 with 5–8 spines along anterior ridge; with 1 transverse stria and several short arcuate striae laterally. Tergite 3 unarmed, with 1 transverse stria. Tergite 4 with medially interrupted transverse stria. Tergite 5 with 2 striae.

Eye: Large, with maximum corneal diameter half basal distance between anterolateral spines; peduncle with few distal setae.

Antennule: Basal segment elongate, slightly overreaching cornea; distolateral spine longer than mesial spine; with 2 lateral spines, distal markedly longer than proximal.

Antenna: Basal segment with strong mesial spine, apex not reaching beyond segment 2. Segment 2 with small spine on mesial and lateral margins; distomesial spine reaching to about midlength of segment 4, lateral reaching to midlength of segment 3. Segments 3 and 4 unarmed.

Maxilliped 3: Ischium with small distal flexor tooth. Merus shorter than ischium; flexor margin with strong distal and proximal spine (except in 12.2 mm female, lacking distal spine); extensor margin unarmed.

Pereopod 1 (cheliped): About 1.5 times carapace length; with few rows of spines and few short squamae; sparsely setose. Dactylus longer than palm; unarmed dorsally; occlusal margin denticulate, without gape. Propodus palm 1.9 times as long as high, surface spinose; pollex with 2 subdistal spines, and strong spine on proximal ventral margin. Carpus 1.8 times long as high, shorter than palm; strongly spinose dorsally, surface with 2 rows of small spines. Merus with strong distal and dorsal spines, surface otherwise unarmed except for row of 6 small lateral spines.

Pereopod 2: Merus with 9 extensor and 6 flexor spines. Carpus with 2 extensor and distal flexor spine. Propodus 6.4 times as long as high; extensor margin unarmed; flexor margin with 7 small movable spines. Dactylus 0.8 propodus length; flexor margin with 8 movable spines, distalmost spine at base of unguis.

Pereopod 3: Merus with 8 extensor and 4 flexor spines. Carpus with 2 extensor and distal flexor spine. Propodus 6.7 times as long as high; extensor margin unarmed; flexor margin with 8 small movable spines. Dactylus 0.7 propodus length; flexor margin with 8 movable spines, distalmost spine at base of unguis.

Pereopod 4: Merus with 4 or 5 small, proximal extensor spines; with 3 flexor spines. Carpus with distal extensor and flexor spine. Propodus 6.4 times as long as high; extensor margin unarmed; flexor margin with 6 small movable spines. Dactylus 0.8 propodus length; flexor margin with 8 movable spines, distalmost spine at base of unguis.

Colour in life. Carapace and abdomen dull red-orange. Chelipeds dull red-orange with white fingers. Walking legs dull red-orange with dactyli and distal half of propodi white.

Remarks. Munida tangaroa sp. nov. resembles M. rubrimana sp. nov. in most respects, sharing five branchial marginal spines on the carapace, anterior branchial and postcervical spines, a row of spines along the anterior ridge of abdominal tergite 2, relatively short chelipeds with proximal and subterminal spines on the margin of the pollex, absence of granular patches on sternite 7, and the distalmost flexor dactyl spine of the walking legs inserting at the base of the unguis. Munida tangaroa differs from M. rubrimana in colour pattern (dull red-orange overall with white pereopodal extremities versus pale, diffuse pink body and red chelipeds) and in the distinctly unequal (lateral longer) rather than subequal terminal spines on the basal antennular segment.

The specimens of the type series are morphologically uniform in most respects, differing chiefly in the spination of abdominal tergite 2 increasing allometrically from five spines in the smallest specimen to eight in specimens exceeding 10 mm carapace length. The 12.2 mm female is atypical in lacking the distal flexor spine on the merus of maxilliped 3 and in having a less pronounced proximal spine on the margin of the pollex of the cheliped.

Distribution. Presently known only from west of Norfolk Island; 690– 812 m.

Figures

FIGURE 14. A, Munida exilis sp. nov., male paratype, 11.4 mm, TAN 0308 / 136 (NMNZ). B, Munida howensis sp. nov., male holotype, 19.2 mm, TAN 0308 / 066 (AM). C, Munida redacta sp. nov., male holotype, 9.4 mm, TAN 0308 / 020 (AM). D, Munida rubrimana sp. nov., ovigerous female holotype, 15.0 mm, TAN 0308 / 043 (NMNZ). E, Munida tangaroa sp. nov., ovigerous female paratype, 14.1 mm, TAN 0308 / 29 (NIWA 28070).