Munida stomifera, Macpherson & Rodríguez-Flores & Machordom, 2017

Macpherson, Enrique, Rodríguez-Flores, Paula C. & Machordom, Annie, 2017, New sibling species and new occurrences of squat lobsters (Crustacea, Decapoda) from the western Indian Ocean, European Journal of Taxonomy 343, pp. 1-61 : 25-28

Munida stomifera sp. nov.

urn:lsid:zoobank.org:act:866271CF-0FA5-4EFF-9B5B-DB24A91DCD4E

Fig. 8

Etymology

From the Greek, atomos, small particle, in relation to the small size of the species.

Type material

Holotype

MADAGASCAR: ♀, 2.8 mm, ATIMO VATAE, Stn DW3525, 24°23.61′ S, 47°32.84′ E, 395–407 m, 1 May 2010 ( MNHN-IU-2014-13473 ).

Paratypes

MADAGASCAR: 1 ov. ♀, 4.3 mm, ATIMO VATAE, Stn DW3564, 25°36.79′ S, 46°20.89′ E, 433– 456 m, 6 May 2010 (MNHN-IU-2014-13543); 1 ♀, 3.5 mm, ATIMO VATAE, Stn CP3585, 25°33.10′ S, 44°16.40′ E, 549–576 m, 10 May 2010 (MNHN-IU-2014-13613).

Description

CARAPACE. As long broad, with few secondary striae between main transverse ridges. Ridges with very short non-iridescent setae and few scattered long iridescent and non-plumose setae. Intestinal region smooth. Gastric region with 4–5 pairs of epigastric spines, longest pair behind supraocular spines. Without parahepatic, branchial dorsal and postcervical spines. Frontal margins transverse. Lateral margins slightly convex. First lateral spine at anterolateral angle, moderately long, clearly not reaching level of sinus between rostrum and supraocular spines; 1–2 minute spines in front of anterior branch of cervical groove. Branchial margins with five spines. Rostrum narrowly triangular, about 0.4–0.5 times length of remaining carapace, horizontal, with median dorsal longitudinal carina. Supraocular spines barely reaching midlength of rostrum and clearly not reaching end of corneae, subparalell, directed slightly upwards.

STERNUM. Surfaces of thoracic sternites smooth. Sternite 4 with anterior margin nearly transverse, broadly rounded and contiguous to sternite 3.

ABDOMEN. Anterior ridge of somite 2 with 2 median spines; somites 2–3 each with uninterrupted transverse ridge on tergite behind anterior ridge; somite 4 smooth or with minute setose scales on tergite; somites 5 and 6 smooth, posteromedian margin of somite 6 straight.

EYES. Ocular peduncles as long as broad, maximum corneal diameter 0.4 distance between bases of anterolateral spines.

ANTENNULE. Article 1 with 2 distal spines, distolateral longer than distomesial spine; two lateral spines, distal much longer than proximal and barely exceeding distomesial spine.

ANTENNA. Article 1 with strong distomesial spine barely reaching distal margin of article 2. Article 2 with distomesial spine short, not exceeding article 3; distolateral spine as long as distomesial. Article 3 with short distomesial spine.

MXP3. Ischium with small spine on fleXor distal margin. Merus shorter than ischium; fleXor margin with 2 spines, median stronger than distal spine; extensor margin with distal spine. Carpus unarmed.

P1. 2.0 times carapace length, with few finely setiferous scales, with some long thick iridescent and plumose setae along mesial margin. Merus 0.7–0.8 length of carapace, 1.9–2.1 times as long as carpus, with some dorsal spines; distal spines strong, distomesial spine barely reaching midlength of carpus. Carpus 0.8 length of palm, 1.3–1.4 times as long as broad; with spines along mesial and lateral borders. Palm 1.5 times as long as broad, with row of small dorsal spines; one row of spines along mesial and lateral margins. Fingers 1.1–1.2 length of palm; fiXed finger with row of small spines along entire lateral margin; movable finger with small basal spine.

P2–4. Moderately long and slender, with few long iridiscent and plumose setae along extensor margin. P2 1.7–1.8 times carapace length. Meri shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.7 carapace length, 5 times as long as broad, 1.5 times as long as P2 propodus; P3 merus 4.0 times as long as broad, 1.3 times as long as P3 propodus; P4 merus 3 times as long as broad, as long as P4 propodus. Extensor margins of meri with row of 10–11 small proximally diminishing spines on P2–3, unarmed on P4, eXcept small distal spine; fleXor margins distally with 2–3 spines followed proximally by several eminences; lateral sides unarmed. Carpi with 3–5 spines on eXtensor margin; lateral surface with several granules sub-paralleling eXtensor margin on P2–4; fleXor margin with small distal spine. Propodi 4.5–5.0 (P2–3)–4.5 (P4) times as long as broad; extensor margin unarmed; fleXor margin with 6 slender movable spines on P2–4. Dactyli slender, length 0.8–0.9 that of propodi; fleXor margin with 6 movable spinules along entire border, without a spinule at the base of the unguis; P2 dactylus 10 times as long as wide.

GENETIC DATA. 16S, see Table 1 .

Remarks

The new species is closely related to M. micra sp. nov. from Mozambique (see above). Both species have 5 spines along the branchial lateral margin of the carapace, spines along the anterior ridge of abdominal somite 2, eyes large, and the distomesial spine of antennular article 1 smaller than the distolateral spine. However, they can be distinguished by several characters:

– The rostrum has a median dorsal longitudinal carina in M. stomifera sp. nov., whereas this carina is absent in M. micra sp. nov.

– The carapace is more elongate in M. micra sp. nov. (1.3 times as long as broad) than in M. stomifera sp. nov. (as long as broad).

– The distomesial spine of antennal article 1 not reaching the midlength of the antennal article 2 in M. micra sp. nov., whereas this spine reaches the end of this article in M. stomifera sp. nov.

– The walking legs (P2–4) are longer and more slender in M. micra sp. nov. than in M. stomifera sp. nov. The P2 merus is twice the carapace length in M. micra sp. nov., whereas it is 1.7–1.8 in M. stomifera sp. nov. The P2 merus is twice the carapace length in M. micra sp. nov., whereas it is 1.7–1.8 times in M. stomifera sp. nov. The P2 propodus is 6.2–7.0 times as long as broad in M. micra sp. nov., whereas it is 4.5–5.0 times in M. stomifera sp. nov.

The new species is also closely related to M. leptitis Macpherson, 1994 , from New Caledonia, Indonesia, Vanuatu, Wallis and Futuna, and French Polynesia. They differ by the presence ( M. stomifera sp. nov.) or absence ( M. leptitis ) of spines on the second abdominal somite.

Only part of the 16S was available for M. stomifera sp. nov. Divergence between other species of the area, such as M. shaula (9.9%) were high (> 10%). The closest species found was M. tuberculata Henderson, 1885 , from the southwestern Pacific (see Macpherson 1994), with values around 6.3–6.8%. The new species and M. tuberculata have 5 spines along the branchial lateral margin of the carapace, spines along the anterior ridge of abdominal somite 2, eyes large, and the distomesial spine of antennular article 1 smaller than the distolateral spine. However, the two species can be easily distinguished by the size of the antennal peduncle, with small articles in M. tuberculata and well developed ones in M. stomifera sp. nov.; the epigastric spines are acute in M. stomifera sp. nov., instead of minute and granulated in M. tuberculata . Furthermore, the P1 palm has well developed spines in M. stomifera sp. nov., whereas the palm is armed with granules in M. tuberculata .

Distribution

Madagascar, at 395– 576 m.

Figures

Fig. 8. Munida stomifera sp. nov., holotype, ♀, 2.8 mm (MNHN-IU-2014-13473), Madagascar. 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. Dactylus of right P2, lateral view. H. Left P3, lateral view. I. Right P4, lateral view. Scale bar: A, E–F, H–I = 1.0 mm; B–D, G = 0.5 mm.