Munida isos, Ahyong & Poore, 2004

Ahyong, Shane T. & Poore, Gary C. B., 2004, Deep-water Galatheidae (Crustacea: Decapoda: Anomura) from southern and eastern Australia, Zootaxa 472 (1), pp. 1-76 : 34-38

Munida isos n. sp. ( Fig. 6 )

Munida microps . — Haig, 1973: 273 [part, smaller specimen only]. — Davie, 2002: 65 [part]. [Not M. microps Alcock, 1894 ].

Type material. HOLOTYPE: AM P61818, male (19.1 mm), off St. Patricks Head , Tasmania, 41º35’S, 148º14’E, 1100 m, S05/87/15, K. Graham, 12 Jul 1987 . PARATYPES: AM P61121, 6 males (16.0– 21.3 mm), 14 females (9.1–18.2 mm), off St. Patricks Head , Tasmania, 41º35’S, 148º14’E, 1100 m, S05/87/15, K. Graham, 12 Jul 1987 ; AM P60190, 1 male (6.7 mm), E of Fortescue Bay , 43°08.96’S, 145°15.36’E, 1000 m, TAS­421, J. Lowry et al., 9 Apr 1994 ; NMV J16062 , 1 male (17.2 mm), 39 km NE of Cape Tourville , Tasmania, 41°53.54’S, 148°39.07’E, 732 m, beam trawl , SLOPE 84 , G. Poore et al., 30 Oct 1988 ; NMV J23909 , 1 ovigerous female (18.0 mm), NW Tasmania, 41°06–09’S, 143°50’E, 1098–1281 m, G. Suiter, Sep 1986 ; NMV J39629 , 5 males (18.0– 20.2 mm), 82.9 km SSE of Southeast Cape, Tasmania, ‘ Sister 1’ seamount, 44°16.2’S, 147°17.4’E, 1100 m, epibenthic sled , T. Stranks , 23 Jan 1997 ; SAM C6077 , 4 males (13.2–20.3 mm), 3 ovigerous females (14.3–15.0 mm; ova 0.6 mm), 85 km SE of South East Cape , 44°14.8’S, 147°27.5’E, 1080–1130 m, FV Belinda, K. Gowlett­Holmes , 9 Feb 1992 ; AM P67170, 1 female (11.1 mm), 51 km SE of Green Cape , 37°30’S, 150°33’E, New South Wales, 860 m, FIS Endeavour, 2 Oct 1912 .

Other material. AM P20992, 1 ovigerous female (16.0 mm), E of Broken Bay , 33°32–38’S, 152°00–04’E, 824 m, K75­05­05, 19 Aug 1975 ; NMV J39630 , J41591 – 41618, 2004 specimens, seamounts SSE of South East Cape , Tasmania, 640–1700 m .

Diagnosis. Carapace with long, scattered setae; transverse striae widely spaced, often intervened by short striae or scales; with transverse row of 6 or 7 (usually 6) epigastric spines; with numerous granules on anterolateral region; with 1 or 2 anterior branchial spines; with or without postcervical spine. Frontal margins slightly oblique; rostrum spiniform. Supraocular spines divergent. Margins of carapace with 5 spines posterior to cervical groove. Fourth sternite at most with few short striae; fifth to seventh sternites smooth; ridges demarcating fourth to seventh sternites feebly granular. Second abdominal tergite with row of 6–9 (usually 6) spines on anterior border. Remaining tergites unarmed. Second to third tergites with 1 uninterrupted transverse stria. Fourth tergite with 2 uninterrupted transverse striae. Eye with cornea dilated, maximum diameter about one­quarter distance between anterolateral spines. Basal antennular segment overreaching cornea; with 2 terminal spines, mesial shorter. Basal antennal segment with strong mesial spine; second segment with short mesial and lateral terminal spines, neither overreaching third segment. Maxilliped 3 ischium with distal flexor spine; merus flexor margin with distal and proximal spine. Cheliped slender, 2–3 times carapace length; pollex without ventral spines. Pereopod 2–3 merus with spinose extensor and flexor margins. Pereopod 4 extensor and flexor margins with distal spine. Pereopods 2–4 dactylus with movable spines distributed along entire flexor margin.

Description. Carapace: Transverse striae widely spaced, often intervened by short striae or scales; cervical groove distinct; with transverse row of 6 or 7 (usually 6) epigastric spines; with numerous granules on anterolateral region; with 1 or 2 anterior branchial spines; with or without postcervical spine. Dorsum with long, scattered setae. Frontal margins slightly oblique; rostrum spiniform, faintly upcurved, about twice as long as supraocular spines and up to half remaining carapace length. Supraocular spines divergent, deflected dorsally. Anterolateral spine well developed, situated at anterolateral angle, extending almost to sinus between rostrum and supraocular spine. Margins of carapace anterior to cervical groove with 2 or 3 (usually 2) spines (including anterolateral); with 5 spines posterior to cervical groove.

Sternum: Fourth sternite at most with few short striae; fifth to seventh sternites smooth; ridges demarcating fourth to seventh sternites feebly granular.

Abdomen: Tergites with scattered setae. Second tergite with row of 6–9 (usually 6) spines on anterior border. Remaining tergites unarmed. Second to third tergites with 1 uninterrupted transverse stria. Fourth tergite with 2 uninterrupted transverse striae.

Eye: Cornea dilated, with maximum corneal diameter about one­quarter distance between anterolateral spines.

Antennule: Basal segment overreaching cornea; with 2 terminal spines, mesial shorter; with two lateral spines, distal markedly longer than proximal.

Antenna: Basal segment of peduncle with strong mesial spine. Second segment with short mesial and lateral terminal spines, neither overreaching third segment.

Maxilliped 3: Ischium with distal flexor spine. Flexor margin of merus with distal and proximal spine, proximal largest; extensor margin unarmed.

Pereopod 1 (cheliped): Slender, 2–3 times carapace length; sparsely setose and spinose. Dorsal margin of dactylus with proximal spine and 1 or 2 other small spines along length; occlusal margin denticulate. Propodus upper and outer margin spinose; palm about 4 times as long as high, dorsal margin slightly longer than dactylus; pollex with 2 subterminal spines, occlusal margin denticulate, ventral margin unarmed. Carpus and merus with irregularly distributed spines on lateral, dorsal and mesial surfaces.

Pereopod 2: Merus extensor margin with 9–13 spines; flexor margin with 5 or 6 spines. Carpus with 4 extensor and 1 flexor spine. Propodus flexor margin with 7 or 8 spines. Dactylus with 17 or 18 movable spines distributed along entire flexor margin.

Pereopod 3: Merus extensor margin with 9–11 spines; flexor margin with 3 or 4 spines. Carpus with 5 extensor and 1 flexor spine. Propodus flexor margin with 7 spines. Dactylus with 12–16 movable spines distributed along entire flexor margin.

Pereopod 4: Merus and carpus extensor and flexor margins each with distal spine. Propodus flexor margin with 5–7 spines. Dactylus with 11 or 12 movable spines distributed along entire flexor margin.

Etymology. Named isos, Greek , meaning ‘equal’ or ‘like,’ alluding to the similarity of the species to M. remota .

Remarks. Munida isos n. sp. appears to be closest to M. remota Baba, 1990 , from Madagascar, in having similar spination and ornamentation of the carapace, walking legs and sternum. The most obvious characters distinguishing M. isos from M. remota are: the cornea is distinctly dilated instead of being only slightly broader than the stalk; the mesial spine of the basal antennal segment is as long as instead of distinctly shorter than the second antennal segment; and the mesial spine on the second antennal segment is shorter than instead of longer than the third antennal segment.

Of the regional species, M. isos closely resembles M. endeavourae , but is readily distinguished by: the cornea is dilated instead of narrow; the inner spine of the second segment of the antennal peduncle does not exceed the third segment; and the carapace bears long scattered setae on the dorsum.

Variation in the present series is slight. Usually two lateral carapace spines are present anterior to the cervical groove, but occasionally a small third spine is present between the usual two. Similarly, additional spines are sometimes present among the usual six spines on the anterior border of the second abdominal tergite, and a postcervical spine is sometimes present on the carapace behind the anterior branchial spines.

Distribution. Known only from east of Broken Bay, New South Wales, south to Tasmania; 640–1700 m. Munida isos is abundant on the seamounts off southeastern Tasmania.

Figures

FIGURE 6. Munida isos n. sp., holotype male (19.1 mm), AM P61818. A, dorsum. B, left basal antennular segment, ventral. C, left antennal peduncle, ventral. D, right third maxilliped, lateral. E, right cheliped. F–H, right pereopods 2–4, dorsal. I, sternum. Scale A, E–H = 5 mm, B–D, I = 2.5 mm.