Munida icela, Ahyong, Shane T., 2007

Ahyong, Shane T., 2007, Decapod Crustacea collected by the NORFANZ Expedition: Galatheidae and Polychelidae, Zootaxa 1593, pp. 1-54 : 31-34

Munida icela sp. nov.

( Fig. 16 )

Type material. Holotype: NMNZ, male (10.3 mm), West Norfolk Ridge, 34°37.20’S, 168°57.03’E, 521–539 m, TAN0308/154 #25, 3 Jun 2003. Paratypes: NIWA 28069, 2 males (9.5–11.1 mm), West Norfolk Ridge, 34°37.20’S, 168°57.03’E, 521–539 m, TAN0308/154 #25, 3 Jun 2003.

Diagnosis. Carapace margins with 5 spines posterior to cervical groove; transverse ridges well-spaced, generally entire, with few secondary striae an anterior half and cardiac region of carapace; anterior branchial and postcervical spines present; frontal margins transverse. Rostrum spiniform. Sternite 4 smooth; anterior margin broadly and evenly convex. Sternites 5 and 6 smooth. Sternite 7 with granular patch laterally. 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 terminal spines subequal. Maxilliped 3 merus extensor margin unarmed. Cheliped 3 times carapace length. Pereopods 2 and 3 propodus extensor margin spinose proximally; dactylus with distalmost flexor spine at base of corneous unguis.

Description. Carapace: Transverse ridges well-spaced, generally entire, with few secondary striae an anterior half and cardiac region of carapace; gastric, hepatic and branchial regions with several short striae; cervical groove distinct; with pair of distinct epigastric spines behind supraocular spines, flanked mesially and laterally small spine and granule; with 1 parahepatic, 1 anterior branchial and 1 postcervical spine. Frontal margins transverse; rostrum spiniform, horizontal, three times as long as supraocular spines and more than half remaining carapace length. Supraocular spines parallel. Anterolateral spines situated at anterolateral angle, slightly divergent, 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 broad, anterior margin sinuous, truncate laterally. Sternite 4 smooth; anterior margin broadly and evenly convex. Sternites 5 and 6 smooth. Sternite 7 with granular patch laterally. Ridges demarcating sternites smooth or slightly crenulate.

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

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

Antennule: Basal segment elongate, slightly overreaching cornea, with scattered ventral striae; terminal spines subequal; with 2 lateral spines, distal markedly longer than proximal.

Antenna: Basal segment with strong mesial spine, apex reaching base of segment 3. Segment 2 with small spine on mesial margin; distomesial spine overreaching segment 4; distolateral spine reaching end of segment 3. Segments 3 and 4 unarmed.

Maxilliped 3: Ischium with strong distal flexor spine; extensor margin unarmed. Merus shorter than ischium; flexor margin with strong distal and proximal spines; extensor margin unarmed.

Pereopod 1 (cheliped): About 3.0 times carapace length; sparsely setose; with scattered striae and granules and multiple rows of small spines. Dactylus slightly longer than palm; with small proximal and distal spine; occlusal margin denticulate, without gape. Propodus palm about 5 times as long as high, with dorsal, medial and ventral rows of short spines. Pollex with 2 subdistal spines; ventral margin unarmed. Carpus about 4 times as long as high, shorter than palm; with dorsal, medial and ventral rows of spines, longest dorsally. Merus with strong distal and dorsal spines, longest not reaching proximal quarter of carpus; lateral surface with short striae and row of 8 or 9 small spines.

Pereopod 2: Merus with 13–15 extensor and 6–9 graded flexor spines. Carpus with 4 or 5 extensor spines and distal flexor spine. Propodus 5.3 times as long as high; extensor margin with 6 or 7 spines proximally; flexor margin with 9 or 10 small movable spines. Dactylus 0.6 propodus length; flexor margin with 9 or 10 movable spines, distalmost spine at base of corneous unguis.

Pereopod 3: Merus with 8 or 9 extensor and 4 or 5 graded flexor spines. Carpus with 4 or 5 extensor spines and distal flexor spine. Propodus 5.0 times as long as high; extensor margin with 5 or 6 spines proximally; flexor margin with 10 small movable spines. Dactylus 0.6 propodus length; flexor margin with 8 or 9 movable spines, distalmost spine at base of corneous unguis.

Pereopod 4: Merus with 4 small proximal extensor spines, distally unarmed; with 4 graded flexor spines. Carpus extensor margin with distal flexor and extensor spine. Propodus 4.3 times as long as high; extensor margin unarmed; flexor margin with 6 or 7 small movable spines. Dactylus 0.6 propodus length; flexor margin with 8 movable spines, distalmost spine at base of corneous unguis.

Etymology. Derived from ikelos, Greek for like, alluding to the similarity of the new species to M. acacia sp. nov. and M. spinicruris Ahyong & Poore, 2004 .

Remarks. Munida icela sp. nov. closely resembles M. spinicruris Ahyong & Poore, 2004 , and M. acacia sp. nov. in bearing five spines on the branchial carapace margins, a row of spines along the anterior ridge of the abdominal tergite 2, and armed dorsal margins of the propodi of the first two walking legs. Munida icela is readily distinguished from M. spinicruris as follows: the eyes are larger, being greater, rather than less than one-third of the distance between the anterolateral spines; the distomesial spine of the basal antennular segment is as long as rather than longer than the lateral spine; the cheliped is triple rather than less than twice carapace length. Characters distinguishing M. icela from M. acacia are discussed under the account of the latter.

Distribution. Presently known only from the West Norfolk Ridge; 521– 539 m.

Figures

FIGURE 16. Munida icela sp. nov., male holotype, 10.3 mm, TAN 0308 / 154 (NMNZ). A, dorsal view. B, left antennule, ventral view. C, left antenna, ventral view. D, right third maxilliped, lateral view. E, sternum. F, right cheliped, lateral view. G – I, right pereopods 2 – 4. Scale: A, F – I = 2.5 mm; B – E = 1.2 mm.