Munidopsis solidissima, Published, 2007

Published, First, 2007, Species of the genus Munidopsis Whiteaves, 1784 from the Indian and Pacific Oceans and reestablishment of the genus Galacantha A. Milne-Edwards, 1880 (Crustacea, Decapoda, Galatheidae), Zootaxa 1417, pp. 1-135 : 100-103

Munidopsis solidissima n. sp.

( Fig. 46)

Material examined. SE Madagascar, SAFARI 1, Stn 15 (CP08), 3825 m: 1 F 24.8 mm, holotype ( MNHN Ga 1428) .

Etymology. From the superlative of the Latin solidus, thick, dense, in reference to the body shape.

Description. Carapace slightly longer than broad, covered with some fine setae, bearing short, interrupted ridges numerous on posterior half; gastric region convex without spines or blunt processes; cardiac transverse ridge preceded by shallow depression expanded laterally, anterobranchial regions with some small spines. Cardiac region faintly delineated in triangular shape, anteriorly without distinct transverse ridge but proceded by shallow concavity anterolateral to it on each side. Rostrum broadly triangular, nearly horizontal, moder- ately carinate dorsally, bearing sparse granules, ventral surface carinate and convex on distal half; length 0.4 times that of remaining carapace, maximum width nearly 0.3 times carapace width. Front margin oblique, with small antennal spine. Lateral margins somewhat convex; anterolateral spine slightly larger than antennal spine, directed forward, and smaller than following spine; anterior branchial margin with rounded ridge overhanging pterygostomian flap, bearing 6 or 7 posteriorly diminishing spines; deep excavation between anterior and posterior branchial regions followed by expanded spiny processes.

Sternum as long as wide, maximum width at sternite 7. Sternite 3 very narrow, anterior margin divided into 2 lobes by deep median notch, each lobe dentate, lateral margin convex. Sternite 4 narrowly elongate anteriorly, width 3 times that of preceding sternite.

Abdominal segments spineless, segments 2–4 each bearing rounded anterior ridge followed by shallow groove. Segment 6 without produced posteromedian lobe, not exceeding lateral lobes. Telson divided into 8 plates, posterior plates combined nearly twice wider than long.

Ocular peduncle hardly movable, relatively broad, bearing lateral and mesial eye-spines, lateral one small, mesial one strongly produced beyond cornea. Cornea small and lateral.

Basal article of antennule with long dorsolateral and distolateral spines and small distomesial granulate process; distoventral portion tuberculate, bearing small spine lateral to base of distolateral spine.

Antennal peduncle well-developed; article 1 with distomesial acute process somewhat larger than distolateral, both strong; article 2 with one well-developed distolateral and one minute distomesial spine; article 3 unarmed.

Mxp 3 ischium with 20 closely placed denticles along crista dentata, extensor margin with distinct distal spine. Merus as long as ischium; flexor margin with 5 or 6 low, obtuse processes of irregular size, extensor margin distally produced into spine.

P1 setose, slightly longer than carapace. Merus relatively short, nearly reaching tip of rostrum, bearing row of dorsal spines and several larger distal spines (dorsomesial, dorsal and lateral). Carpus as long as high, with one mesial marginal spine, a few small lateral and several dorsal distal spines. Palm as long as high, somewhat depressed, unarmed, dorsally with scattered granules. Fingers having opposable margins straight, distally spooned, bearing denticles; fixed finger with denticulate carina on distolateral margin.

P2–P4 setose, moderately short. P2 1.5 times carapace length, overreaching end of P1. P2 merus 1.3 times longer than that of P4, 3 times longer than high, twice carpus length and nearly 1.5 times propodus length, with row of low dorsal spines, ventral margin with distal spine; carpus with some spines along dorsal border, increasing in size distally, and some spines on lateral crest; propodus subcylindrical in cross section, 3.5 times longer than high, with feebly tuberculate crest on lateral face, dorsal margin with a few small spines on proximal half, 2 distal movable spinules on ventral margin; dactylus more than half of propodus, ending in sharp curved claw, flexor margin nearly straight, with row of 8 or 9 teeth diminishing in size toward base of article, ultimate tooth closer to penultimate one than to end of terminal claw, each tooth with seta.

Epipods present on P1.

Remarks. Munidopsis solidissima belongs to the group of species having a wide triangular rostrum, without epigastric spines or processes, main well-developed eye-spine on mesial end of eyestalk, fixed finger of P1 with denticulate carina on distolateral margin, P2 overreaching P1, and epipods on P1. The new species resembles M. profunda from the Celebes Sea (5163–5243 m) and Taiwan (3564–4455 m) ( Baba 2005, Osawa et al. 2006b). However, they differ in the following aspects:

— The carapace is clearly longer than wide in M. profunda , instead of as long as wide in M. solidissima .

— Rostrum clearly broader in the new species than in M. profunda ; the maximum width of rostrum is nearly 0.2 times that of the carapace in M. profunda , being 0.3 times in the new species.

— The front margin is more oblique in M. profunda than in M. solidissima .

— The meri, carpi and propodi of P2–P4 bear a row of well-developed spines along dorsal and dorsal margins in M. profunda , whereas these spines are clearly smaller and less numerous in the new species; ventral margins of meri bear a row of spines in M. profunda , being unarmed (except distal spine) in M. solidissima .

The new species is also close to M. aries A. Milne-Edwards, 1880 , from the Atlantic Ocean ( Macpherson & Segonzac 2005). They can be easily distinguished by the lateral margin of carapace having a crest sharply salient and carinate in M. aries , being rounded and not salient in the new species. Furthermore, M. aries has two small epigastric processes, which are absent in M. solidissima , and the dorsal carapace surface has clearly

more numerous granules and striae in M. aries than in the new species.

Distribution. Only known from the south of Madagascar, at 3825 m.