Munida acola, 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 : 433-435

Munida acola n. sp.

( Fig. 1 )

HOLOTYPE. — Loyalty Islands. LIFOU 2000 , stn 1414, 20°45.9’S, 167°06.2’E, 4-7 m, 20.XI.2000, ♂ 4.1 mm (MNHN-Ga 6692).

PARATYPES. — Loyalty Islands. LIFOU 2000, stn 1414, 20°45.9’S, 167°06.2’E, 4-7 m, 20.XI.2000, 2 ovig. ♀♀ 3.7, 3.8 mm, 1 ♀ 2.9 mm (MNHN-Ga 6693). — Stn 1437, 20°55.5’S, 167°04.2’E, 10-30 m, 10.XI.2000, 1 ♂ 3.0 mm (MNHN-Ga 6694). — Stn 1458, 20°46.7’S, 167°08.1’E, 17-24 m, 4.XI.2000, 3 ♂♂ 2.8-3.1 mm, 1 ♀ 3.0 mm (MNHN-Ga 6695).

ETYMOLOGY. — From the Greek, akolos, bit, in reference to the small size of the species.

DISTRIBUTION. — Loyalty Islands, 4- 30 m.

DESCRIPTION

Carapace 1.2 times longer than wide. Few secondary striae between main transverse ridges. Ridges with numerous very short non-iridescent setae and few simple iridescent setae. Intestinal region without scales. Gastric region with 9 or 10 epigastric spines. One parahepatic and one postcervical spine on each side.Frontal margins slightly oblique.Lateral margins slightly convex.Anteriormost spine situated at anterolateral angle, well developed, clearly not reaching level of sinus between rostrum and supraocular spines. Second spine anterior to cervical groove half length of preceding one.Branchial margins with five spines. Rostrum spiniform, about half length of remaining carapace, straight and horizontal.Supraocular spines reaching mid length of rostrum and not reaching distal corneal margins, slightly divergent, and directed slightly upwards ( Fig. 1A ).

Anterior part of fourth sternite slightly concave medially, contiguous to posterior margin of third sternite. Fourth thoracic sternite with a few small scaly striae; surface of fifth to seventh sternites smooth. Transverse ridges between fifth, sixth and seventh sternites obtuse, feebly granulated ( Fig. 1B ).

Abdominal somites unarmed. Second and third somites each with one transverse stria.

Eyes small, maximum corneal diameter about one-third distance between bases of anterolateral spines.

Basal segment of antennule (distal spines excluded) about one-fourth carapace length, overreaching end of corneae, distance between distal end of article and base of dorsolateral spine half length of remaining proximal portion; two distal spines, mesial spine clearly longer than lateral; two spines on lateral margin, proximal one short, located at mid length of segment, distal one long, nearly reaching end of distal spines ( Fig. 1C ). First segment of antennal peduncle with moderately long distomesial spine reaching end of second segment; second segment with two distal spines, mesial spine longer than lateral spine, reaching end of antennal peduncle; third segment unarmed ( Fig. 1C ).

Mxp3 ischium about 1.5 times length of merus measured along extensor margin, distoventrally bearing spine. Merus with one well-developed median spine on flexor margin, distal small; extensor distal margin with small spine ( Fig. 1D ).

P1 moderately squamous, with numerous plumose setae and few uniramous setae, denser along lateral and mesial margins. Palm slightly longer than fingers. Merus armed with some spines, strong spines on distal border, not overreaching proximal quarter of carpus. Carpus 1.5 times longer than high, with several spines on lateral sides. Palm with some spines along mesial and lateral sides. Fixed and movable fingers with row of spines along lateral and mesial margins, respectively, distally curving and crossing, ending in a sharp point ( Fig. 1E ).

P2 lost in most specimens. P3 nearly twice carapace length; merus half carapace length, about 4.5 times as long as high, about 2.5 times carpus length and slightly longer than propodus; propodus about six times as long as high, about 1.5 times dactylus length ( Fig. 1F ). P3 merus with small spines on extensor border, increasing in size distally, ventral margin with one well-developed distal spine; carpus with several extensor spines and one distoventral spine; propodus with 9 or 10 movable ventral spines; dactylus slightly curving distally, with 9 movable spinules along entire flexor margin. P4 merus 0.8 length of P3 merus; merocarpal articulation reaching level of anterior end of cervical groove.

REMARKS

Munida acola n. sp. belongs to the group of species having five spines on the branchial lateral margins of the carapace, smooth thoracic sternites, welldeveloped eyes, the P2-P4 dactyli with spines along the entire ventral border, and the second abdominal somite unarmed. The new species is closely related to M. leptitis Macpherson, 1994 from New Caledonia, Loyalty Islands, Indonesia, Wallis and Futuna and French Polynesia ( Baba et al. 2008).

Munida acola n. sp. is easily distinguished from M. leptitis by the following:

– the P1 movable finger has a row of spines instead of one proximal and one distal spine on the mesial margin;

– the maximum corneal diameter is about onethird instead of half the distance between bases of anterolateral spines;

– the distomesial spine of the basal antennular peduncle is clearly longer instead of shorter than the distolateral spine.

Figures

FIG. 1. — Munida acola n. sp., holotype, ♂ 4.1 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, left P1, dorsal view; F, right P3, lateral view; G, right P4, lateral view; H, dactylus of right P3, lateral view. Scale bar: A, E-G, 1 mm; B-D, H, 0.5 mm.