Munida pauxilla, Macpherson, 2009

Macpherson, Enrique, 2009, New species of squat lobsters of the genera Munida and Raymunida (Crustacea, Decapoda, Galatheidae) from Vanuatu and New Caledonia, Zoosystema 31 (3), pp. 431-451 : 442-445

Munida pauxilla n. sp.

( Fig. 5 )

HOLOTYPE. — Vanuatu. SANTO 2006 , stn DB16, 15°35.5’S, 167°15.8’E, 32-40 m, 14.IX.2006, ovig. ♀ 5.5 mm (MNHN-Ga 6704).

PARATYPES. — Loyalty Islands. LIFOU 2000, stn 1413, 20°55.3’S, 167°05.0’E, 3-10 m, 15-18, 26 and 27.XI.2000, 7 ♂♂ 4.0- 4.9 mm, 1 ovig. ♀ 3.4 mm, 3 ♀♀ 4.5-5.0 mm (MNHN-Ga 6705). — Stn 1414, 20°45.9’S, 167°06.2’E, 4-7 m, 20.XI.2000, 2 ♂♂ 4.0, 4.3 mm, 3 ovig. ♀♀ 4.0-7.0 mm, 8 ♀♀ 3.5-6.5 mm (MNHN-Ga 6706). — Stn 1415, 20°47.1’S, 167°09.1’E, 3-7 m, 25.XI.2000, 10 ♂♂ 2.8-5.2 mm, 5 ovig. ♀♀ 3.8-6.6 mm, 1 ♀ 3.6 mm (MNHN-Ga 6707). — Stn 1437, 20°55.5’S, 167°04.2’E, 10-30 m, 10.XI.2000, 2 ♂♂ 3.9, 4.5 mm, 4 ovig. ♀♀ 4.3-5.4 mm (MNHN-Ga 6708). — Stn 1445, 20°50.8’S, 167°09.7’E, 10-12 m, 16.XI.2000, 1 ♂ 3.8 mm, 1 ♀ 5.2 mm (MNHN-Ga 6709). — Stn 1452, 20°54.6’S, 167°02.1’E, 2-25 m, 20-22.XI.2000, 1 ♂ 5.4 mm, 2 ovig. ♀♀ 3.3, 3.7 mm (MNHN-Ga 6710). — Stn 1455, 20°56.8’S, 167°02.7’E, 15-20 m, 25.XI.2000, 3 ♂♂ 3.8-6.2 mm, 3 ovig. ♀♀ 3.3-6.4 mm, 6 ♀♀ 3.2-5.7 mm (MNHN-Ga 6711).

ETYMOLOGY. — From the Latin pauxillus, dim, in reference to the small size of the species.

DISTRIBUTION. — Vanuatu, 32-42 m, Loyalty Islands, 2- 30 m.

DESCRIPTION

Carapace 1.2 times longer than wide.Main transverse ridges usually interrupted in cardiac regions, with very short, non-iridescent setae, and some scattered long iridiscent setae. Few secondary striae between main ridges. Intestinal region without scales. Dorsal surface of carapace armed with row of 9 or 10 epigastric spines and some scattered spines between this row and first main stria; one small hepatic, one parahepatic, 1 or 2 anterobranchial and one postcervical spine on each side. Frontal margins strongly oblique. Lateral margins slightly convex. First lateral spine well developed, situated on the frontal margin, mesial to anterolateral angle, clearly not reaching level of sinus between rostrum and supraocular spines. Second spine very small, third spine situated at anterolateral angle, about half length of first spine; fourth spine in front of cervical groove very small or absent.Branchial margins with 5 spines. Rostrum spiniform, horizontal. Supraocular spines well developed, reaching mid length of rostrum and not reaching end of corneae, subparallel, directed slightly upwards ( Fig. 5A ).

Fourth thoracic sternite smooth, with few short striae; other sternites smooth. Anterior part of fourth sternite slightly narrower than third, contiguous to median part of posterior margin of third sternite ( Fig. 5B ).

Abdominal somites unarmed.Second and third abdominal somites each with two transverse ridges.

Epistomic crest with jump near mouth.

Eyes large, maximum corneal diameter about 0.4 times distance between bases of anterolateral spines.

Basal segment of antennule (distal spines excluded) about 0.5 carapace length, elongate, about 2.5 times longer than wide (excluding spines), slightly exceeding end of corneae, with 2 distal spines, mesial spine longer than lateral; 2 spines on lateral margin, proximal one short, located at mid length of segment, distal one long, reaching end of distal spines ( Fig. 5C ); distance between distal end of segment and base of dorsolateral spine 0.3 length of remaining proximal portion. First segment of antennal peduncle with distomesial spine overreaching end of second segment; second segment with 2 long distal spines, mesial spine longer than lateral spine, slightly exceeding antennal peduncle; third segment unarmed ( Fig. 5C ).

Mxp3 ischium about 1.7 times length of merus measured along extensor margin, distoventrally bearing spine. Merus with 2 well-developed spines on flexor margin, distal smaller; extensor margin with distal spine ( Fig. 5D ).

P1 subequal in length, 2.5 times carapace length, squamous, with numerous uniramous iridescent setae and plumose non-iridiscent setae, denser on mesial and lateral borders of articles. Merus shorter than carapace, c. 2.5 times carpus length, armed with some spines, strongest spine on distal border, reaching proximal half of carpus. Carpus 1.5 times as long as high, shorter than palm, several strong spines on mesial border and some small spines on dorsal side. Palm shorter than fingers, with row of mesial spines, numerous scattered spines on dorsal side and one row of lateral spines continuing onto fixed finger and reaching tip. Movable finger with spines along mesial margin. Fingers distally curving and crossing, ending in sharp point, cutting edges with small teeth of various sizes, fixed finger with proximal process ( Fig. 5E ).

P2 nearly twice carapace length, with numerous uniramous iridiscent setae and plumose noniridiscent setae along extensor margins of articles; merus 4.5 times as long as high, 0.7 times as long as carapace, 3 times as long as carpus and 1.5 times as long as propodus; propodus 4.7 times as long as high, and slightly longer than dactylus ( Fig. 5F ). Extensor border of merus with row of small spines increasing in size distally, flexor margin with few spines increasing in size distally. Carpus with 4 dorsal spines and one distoventral spine; distal margin clearly not reaching level of merocarpal articulation of P1. Propodus with 11 movable spinules along flexor border. Dactylus slightly curving distally, with 7 movable spinules along flexor margin, ultimate spine more remote from tip of dactylus than from penultimate spine. P3 slightly shorter than P2; spination of P3 similar to that of P2 ( Fig. 5G ). P4 shorter than P2; merus 0.7 times length of P2; spines along margins of merus and carpus less spinose than those of P2 and P3; merocarpal articulation reaching level of anterior end of cervical groove.

Colour

Ground colour of carapace and abdomen reddish, with some scattered dark red spots. Rostrum, supraocular and anterolateral spines reddish. P1 merus with white distal band; fingers with proximal and distal white bands. P2-P4 whitish with some red spots.

REMARKS

The new species is closely related to M. olivarae Macpherson, 1994 from New Caledonia, Fiji and Tonga Islands and M. mica n. sp. (see above). These species have five spines on the branchial lateral margin, frontal margin oblique, eyes large, the abdominal somites unarmed, the lateral parts of the posterior thoracic sternites without granules, and the distomesial spine of the basal antennular segment clearly longer than the distolateral. Munida pauxilla n. sp. and M. mica n. sp. are distinguished from M. olivarae by the following characters:

– the supraocular spines are longer in the new species, reaching instead of far falling short of the mid length of the rostrum;

– the distomesial spine of the first segment of antennal peduncle is longer, overreaching instead of nearly reaching the end of the second segment, and the distomesial spine of the second segment slightly exceeding the antennal peduncle, instead of terminating at the end of the third segment;

– the merocarpal articulation of the P4 reaches the level of the end of the cervical groove in M. pauxilla n. sp. and M. mica n. sp.;

Munida mica n. sp. and M. pauxilla n. sp. are distinguished by the following characters:

– the gastric region has spines other than epigastric in M. pauxilla n. sp. These spines are absent in M. mica n. sp.;

– the posterior margin of the third sternite is contiguous to the fourth sternite by the entire length in M. mica n. sp., whereas by only the median portion in M. pauxilla n. sp.;

– the dorsal side of the P1 palm has more spinose in M. pauxilla n. sp. than in M. mica n. sp.;

– the colour patterns are slightly different in both species. Munida pauxilla n. sp. has the ground colour of the carapace and the abdomen reddish, with some scattered dark red spots. Munida mica n. sp. has the ground colour of the carapace and the abdomen light orange; the striae are reddish, and with one red spot on each margin of anterobranchial region.

Figures

FIG. 5. — Munida pauxilla n. sp., holotype, ovig. ♀ 5.5 mm: A, carapace and abdomen, dorsal view; B, sternal plastron; C, cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp3, lateral view; E, right P1, dorsal view; F, right P2, lateral view; G, right P3, lateral view; H, right P4, lateral view. Scale bar: A, B, E-H, 1 mm; C, D, 0.5 mm.