Munida caeli, Cabezas & Macpherson & Machordom, 2009

Cabezas, Patricia, Macpherson, Enrique & Machordom, Annie, 2009, Morphological and molecular description of new species of squat lobster (Crustacea: Decapoda: Galatheidae) from the Solomon and Fiji Islands (South-West Pacific), Zoological Journal of the Linnean Society 156 (3), pp. 465-493 : 469-471

MUNIDA CAELI SP. NOV. ( FIG. 2 )

Material examined: Solomon Islands. SALOMON 1. Stn 1801, 09°25.0′S, 160°25.9′E, 1 October 2001, 254– 271 m: 1 M, 6.5 mm; 1 ov. F, 5.8 mm (paratype, MNHN-Ga6503). Stn 1802, 09°31.1′S, 160°35.0′E, 2 October 2001, 245– 269 m: 1 M, 6.2 mm (paratype, MNHN-Ga6504); 1 ov. F, 6.0 mm (holotype, MNHN-Ga6505) .

Etymology: The name caeli refers to one of the southern hemisphere constellations (the Graving Tool).

Description: Carapace 1.2 times longer than wide, slightly convex dorsally. Transverse ridges mostly interrupted by dense short, non-iridescent setae. Intestinal region without striae or scales. Few scales, and secondary striae between main striae. Gastric region with a row of ten epigastric spines, other regions unarmed. Frontal margins slightly oblique. Lateral margins feebly convex. Anterolateral spine well-developed, situated at anterolateral angle, clearly not reaching the level of the sinus between the rostrum and the supraocular spines. Second marginal spine before cervical groove small, three times smaller than the preceding one. Branchial margins with five small spines, decreasing in size posteriorly. Rostrum spiniform, nearly half as long as remaining carapace, slightly curved. Supraocular spines short, not reaching midlength of rostrum, and clearly not exceeding ends of corneas, subparallel, upwardly directed ( Fig. 2A ).

Fourth thoracic sternite with a few small scales; lateral surface of fifth to seventh sternites smooth. Anterior part of fourth sternite narrower than third, slightly concave medially; median posterior margin of third sternite contiguous with fourth sternite. Transverse ridges between fifth, sixth, and seventh sternites obtuse, feebly granulated ( Fig. 2B ).

Second abdominal tergite with eight spines on anterior ridge. Second and third tergites each with one transverse continuous stria.

Epistome crest without hump near mouth opening.

Eyes moderately large: maximum corneal diameter nearly half of the distance between the bases of the anterolateral spines.

Basal segment of antennule (distal spines excluded) about 0.25 times the carapace length, elongate, ending at the same level or slightly exceeding the corneas, with two distal spines, and with mesial spine shorter than lateral spine; two spines on lateral margin, proximal one short, located at midlength of segment, distal one long, nearly reaching end of distolateral spine ( Fig. 2C ). First segment of antennal peduncle with one distal spine on mesial margin, reaching end of second segment; second segment with two distal spines, mesial spine clearly longer than lateral spine, reaching end of third segment; third segment unarmed ( Fig. 2C ).

With Mxp 3 ischium nearly twice the length of the merus, measured along the dorsal margin, and distoventrally bearing a spine. Merus bearing two spines on flexor margin, proximal spine longer than distal spine; extensor margin unarmed ( Fig. 2D ).

With P1 squamate, three times the carapace length, with a few uniramous setae on the mesial borders of articles. Merus as long as carapace, nearly twice the carpus length, armed with some spines, and with stronger spines on distal border, not reaching proximal fourth of carpus. Carpus 3.5–4.5 times longer than high, shorter than hand, with a few strong spines on the mesial margin, and some short spines on the dorsal side. Palm as long as fingers, with row of spines along mesial and lateral borders, and some small spines on dorsal side. Fingers distally curving and crossing, and ending in a sharp point; fixed finger with some spines along entire border, with two distal spines, and ending in sharp point; movable finger unarmed, except for terminal spine ( Fig. 2E ).

With P2 twice the carapace length; merus slightly shorter than carapace, about 8–11 times as long as high, between four and five times the carpus length, and twice the propodus length; propodus between six and eight times as long as high, and 1.1–1.5 times longer than dactylus ( Fig. 2F ). Merus with row of some spines along dorsal and ventral borders. Carpus with several dorsal spines and one distoventral spine; end of carpus nearly reaching level of the merocarpal articulation of P1. Propodus with 9–12 movable ventral spinules. Dactylus long and slender, with dorsal margin slightly convex on proximal half, slightly curving distally with seven or eight movable spinules along ventral margin, distal third unarmed ( Fig. 2G ). P3 similar in length and armature to P2; P3 merus slightly shorter than P2 merus, and P3 propodus slightly longer than P2 propodus ( Fig. 2H ). P4 shorter than P2 and P3; P4 merus about 0.6 times P2 merus ( Fig. 2I ); merocarpal articulation reaching level of anterolateral spine of carapace.

Remarks: The new species resembles Munida parca Macpherson, 1996 from New Caledonia, and Munida lailai sp. nov. from Fiji (see below), in that it has five spines on the lateral margin of the carapace behind the cervical groove, eyes moderately large, the second abdominal segment with spines, lateral sections of the posterior thoracic sternites without granules, rostrum spiniform, the distomesial spine of the basal antennular segment clearly shorter than the distolateral spine, the distomesial spine of the second antennal article reaching the end of the third article, and with the distal half of the ventral border of the dactylus unarmed. The species can be easily distinguished from M. parca according to the following characters.

1. The antennular peduncle is longer in M. parca than in M. caeli sp. nov. The basal article is very long and clearly exceeds the corneae in M. parca , whereas this article only ends or slightly exceeds the corneae in the new species.

2. The distomesial spine of the second antennal segment exceeds the third segment in the new species, whereas this spine is shorter in M. parca , and falls short of the distal margin of the third segment.

3. The chelipeds (P1) are more elongate in the new species, with the carpus being 3.5–4.5 times longer than broad, whereas the carpus is twice as long as it is broad in M. parca .

Munida caeli sp. nov. is also closely related to M. lailai sp. nov. (see the differences under the Remarks section of M. lailai sp. nov.).

Distribution: Solomon Islands, at a depth of between 245 and 271 m.

Figures

Figure 2. Munida caeli sp. nov., ovigerous female holotype, 6.0 mm (MNHN Ga6505). Solomon Islands. A, carapace and abdomen, dorsal view. B, sternum. C, left antennule and antenna, ventral view. D, ischium and merus of right third maxilliped, lateral view. E, right cheliped, lateral view. F, right P2, lateral view. G, dactylus, right P2, lateral view. H, right P3, lateral view. I, right P4, lateral view. Scale: A, B, E, F, H, I = 1 mm; C, D, G = 0.5 mm.