Munida parile, Macpherson & Machordom, 2005

Macpherson, E. & Machordom, A., 2005, Use of morphological and molecular data to identify three new sibling species of the genus Munida Leach, 1820 (Crustacea, Decapoda, Galatheidae) from New Caledonia, Journal of Natural History 39 (11), pp. 819-834 : 821-825

Munida parile sp. nov.

( Figure 1 )

Material examined

NORFOLK 1, stn 1695, 24 June 2001, 24 ° 39.665 9 S, 168 ° 38.812 9 E, 562–587 m: two males 4.0– 5.1 mm; stn 1697, 24 June 2001, 24 ° 39.500 9 S, 168 ° 38.273 9 E, 569–616 m: one male 3.5 mm; stn 1699, 24 June 2001, 24 ° 39.679 9 S, 168 ° 39.978 9 E, 581–600 m: one male 7.6 mm; stn 1701, 24 June 2001, 24 ° 40.228 9 S, 168 ° 39.296 9 E, 564–586 m: one ovigerous female 3.7 mm (holotype, MNHN-Ga 4616).

NORFOLK 2, stn 2061, 25 October 2003, 24 ° 39.50 9 S, 168 ° 40.32 9 E, 620–1040 m: one female 4.8 mm; stn 2069, 26 October 2003, 25 ° 20.07 9 S, 168 ° 57.60 9 E, 795–852 m: one male 5.1 mm; stn 2078, 27 October 2003, 25 ° 20.70 9 S, 168 ° 18.60 9 E, 654–877 m: one male 3.9 mm.

Etymology

From the Latin, par, equal, like, in reference to the similarity to M. tuberculata .

Description

Carapace slightly longer than wide. Transverse ridges mostly interrupted on cardiac region, with few short, non-iridescent setae. Main transverse striae on posterior part of carapace interrupted in cardiac region. Small scales on hepatic and anterobranchial regions. Intestinal region without striae. Gastric region with row of small epigastric spines. One parahepatic, one or two anterobranchial and one postcervical spine on each side. Frontal margins transverse. Lateral margins slightly convex. Anterolateral spine well developed, situated at anterolateral angle, not reaching level of sinus between rostrum and supraocular spines. One to two small marginal spines before cervical groove. Branchial margins with five small spines. Rostrum spiniform, half as long as remaining carapace, horizontal. Supraocular spines short, not reaching midlength of rostrum or end of corneas, parallel, directed upwards ( Figure 1A ).

Thoracic sternites smooth, without granules or carinae. Few short scales on fourth sternite. Anterior part of fourth sternite narrower than third ( Figure 1B ).

Anterior ridge of second abdominal somite with six spines. Second to fourth somites each with one transverse stria.

Eyes large, maximum corneal diameter a third of the distance between bases of anterolateral spines.

Basal segment of antennule (distal spines excluded), about one-third carapace length, elongate, over-reaching corneae, with two distal spines, mesial spine shorter than lateral spine; two spines on lateral margin, proximal one short, located at midlength of segment, distal one long, reaching end of distolateral spine ( Figure 1C ).

Antennal peduncle reduced. First segment with one short distal spine on mesial margin, nearly reaching end of second segment, and reaching base of basal antennular segment; second segment with two short distal spines, mesial spine not reaching end of third segment; third segment with small distomesial spine ( Figure 1C ).

Ischium of third maxilliped about twice length of merus measured along dorsal margin, distoventrally bearing spine. Merus of third maxilliped with three spines on flexor margin, median smaller; extensor margin unarmed ( Figure 1D ).

Chelipeds subequal, squamous, with a few short uniramous, non-iridescent setae. Palm slightly shorter than fingers. Merus armed with some spines, strongest spine on distal border short, reaching proximal third of carpus. Carpus with some spines on dorsal side and several spines scattered on mesial and ventral sides. Palm with several spines scattered on mesial and dorsal sides and one row of lateral very short spines, continuing along fixed finger. Fingers distally curving and crossing, ending in a sharp point; movable, with one basal spine on mesial border; cutting edges with small teeth of distinct sizes ( Figure 1E ).

Second pereiopod slightly shorter than twice carapace length; merus shorter than carapace, about five times as long as high, about three times carpus length and 1.6 times as long as propodus; propodus four times longer than height, as long as dactylus ( Figure 1F ). Merus with small spines on dorsal border, increasing in size distally, ventral margin with several spines and one long distal spine. Carpus with few dorsal spines and one distoventral spine. Propodus with eight to nine movable ventral spines. Dactylus slightly curving distally, with eight to nine movable spinules along entire ventral margin ( Figure 1G ). Third pereiopod similar to second; fourth pereiopod shorter than second and third. Merus of fourth pereiopod two-thirds length of second pereiopod.

Remarks

Munida parile belongs to the group of species with the following features: five spines on the lateral margins of the carapace behind the cervical groove, large eyes, spines along the anterior ridge of the second abdominal somite, no granules or carinae on the lateral parts of the posterior thoracic sternites, spiniform rostrum, a longer distolateral than distomesial spine of the basal antennular segment, small antennal peduncle and a row of spinules along the entire ventral border of the dactylus of the walking legs. The new species is closely related to M. tuberculata Henderson, 1885 found between 435 and 650 m in New Caledonia, Matthew and Hunter Islands and Fiji Islands (type locality) ( Henderson 1888; Macpherson 1994, 2004). For comparison, the material of M. tuberculata listed in Macpherson (1994, 2004) and specimens collected from distinct localities, including type material ( Table I) was examined.

The two species are distinguished by several subtle morphological characters as follows.

The rostral spine is thicker in M. tuberculata than in M. parile . The rostral spine (measured at level of end of corneae) is as wide as or narrower than the second segment of the antennular peduncle (measured at terminal level) in M. parile , whereas the rostral spine is clearly wider in M. tuberculata .

The anterolateral angle of the carapace is more convex in M. tuberculata than in M. parile . Furthermore, the anterolateral spine is situated just on the anterolateral angle in M. parile , while in M. tuberculata it is placed on the frontal margin (see Macpherson 1994, Figure 58).

The granules on the hepatic regions are more numerous and the epigastric spines are more granulated in M. tuberculata than in M. parile .

The molecular data showed a nucleotidic divergence of about 9.7% when the two genes were considered together (4.3% for 16S sequences and 14% for COI; Table II), the greatest divergence of the three pairs of taxa. This divergence corresponds to 27 and 92 diagnostic positions in the 16S and COI, respectively. For the latter, two haplotypes for the three specimens of the new species were found, which differed in only one position among the 657 analysed.

Distribution

New Caledonia, between 562 and 616 m.

Figures

Figure 1. Munida parile sp. nov., ovigerous female 3.7 mm, holotype from stn 1701 (NORFOLK 1). (A) Carapace, dorsal view; (B) sternal plastron; (C) ventral view of cephalic region, showing antennular and antennal peduncles; (D) left third maxilliped, lateral view; (E) right cheliped, dorsal view; (F) left first walking leg, lateral view; (G) dactylus of left first walking leg, lateral view.