Munida micra, 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 : 22-25

Munida micra sp. nov.

urn:lsid:zoobank.org:act:B9620615-3637-4576-B3C1-374F6D016C39

Figs 7 , 12C

Etymology

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

Type material

Holotype

MOZAMBIQUE: ♂, 3.7 mm, MAINBAZA, Stn CC3165, 24°15.70′ S, 35°42.12′ E, 605–612 m, 15 Apr. 2009 ( MNHN-IU-2008-10229 ).

Paratype

MOZAMBIQUE: 1 ♀, 3.5 mm, MAINBAZA, Stn CC 3165, 24°15.70′ S, 35°42.12′ E, 605–612 m, 15 Apr. 2009 (MNHN-IU-2008-13503).

Description

CARAPACE. 1.3 times as long as broad, without 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 3 pairs of epigastric spines, longest pair behind supraocular spines. One parahepatic and one postcervical spine on each side. Frontal margins slightly oblique. Lateral margins straight and slightly convergent posteriorly. First lateral spine at anterolateral angle, moderately long, clearly not reaching level of sinus between rostrum and supraocular spines; second spine small, in front of anterior branch of cervical groove, less than half length of first spine. Branchial margins with five spines. Rostrum spiniform, about 0.6 times length of remaining carapace, not dorsally carinated, horizontal, distal part upwards directed. Supraocular spines not 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 contiguous to sternite 3.

ABDOMEN. Anterior ridge of somite 2 with 2 median spines, 0–1 additional spines on each side; somites 2–3 each with uninterrupted or medially interrupted transverse ridge on tergite behind anterior ridge; somites 4 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 well-developed distal spines, distolateral longer than distomesial spine; two lateral spines, distal much longer than proximal and reaching end of distomesial spine, surface with a few striae.

ANTENNA.Article 1 with small distomesial spine not reaching midlength of article 2. Article 2 with short distomesial and distolateral spines, subequal, not exceeding article 3. Articles 3–4 unarmed.

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. 1.9 times carapace length, with few finely setiferous scales, with few long iridescent and plumose setae along mesial margin. Merus 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 0.9 length of palm, 1.8 times as long as broad; with spines along mesial border. Palm twice as long as broad, with row of small dorsal spines; one row of spines along mesial and lateral margins. Fingers 1.3 length of palm; fiXed finger with row of 4–5 spines along lateral margin; movable finger with basal and subdistal spines.

P2–4. Long and slender, with few long iridiscent and plumose setae along extensor margins of articles. P2 twice carapace length. Meri shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.8 carapace length, 7 times as long as broad, 1.6 times as long as P2 propodus; P3 merus 6 times as long as broad, 1.3 times as long as P3 propodus; P4 merus 4.5 times as long as broad, as long as P4 propodus. Extensor margins of meri with row of 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 1–2 spines on eXtensor margin; lateral surface with several granules sub-paralleling eXtensor margin on P2–4; fleXor margin with small distal spine. Propodi 6.2–7.0 (P2–3)–5.5 (P4) times as long as broad; extensor margin unarmed; fleXor margin with 5 slender movable spines on P2–4. Dactyli slender, length 0.9–1.0 that of propodi; fleXor margin with 5 movable spinules along entire border, without a spinule at base of unguis; P2 dactylus 7.5 times as long as wide.

COLOUR. Ground colour pinkish, with some red patches. Rostrum and supraocular spines reddish, tip of rostrum whitish. P1 whitish, with 3 reddish bands; fingers whitish. P2–4 whitish, without reddish transverse bands.

GENETIC DATA. Not available.

Remarks

Munida micra sp. nov. belongs to the group of species having five spines on the branchial lateral margins of the carapace, smooth thoracic sternites, large eyes, spines on the anterior ridge of the second abdominal somite, and the distomesial spine of antennular article 1 smaller than the distolateral spine. The new species is closely related to M. stomifera sp. nov. from Madagascar (see below under the Remarks of that species), and to M. parile Macpherson & Machordom, 2005 , from New Caledonia.

However, M. micra sp. nov. is easily distinguished from M. parile by several characters:

– The rostrum has a median dorsal carina in M. parile , whereas this carina is absent in the new species. – The distomesial spine of antennal article 1 does not reach the midlength of antennal article 2 in the new species, whereas this spine reaches the end of this article in M. parile .

– The fleXor margin of the MXp3 merus has a distal spine in M. micra sp. nov., but it is unarmed in M. parile .

– The walking legs (P2–4) are clearly longer and more slender in M. micra sp. nov. than in M. parile . The P2 merus is 7 times as long as broad in the new species, whereas it is 5 times in M. parile ; the propodus is 6.2–7.0 times as long as broad in M. micra sp. nov., whereas it is 4 times in M. parile .

Distribution

Mozambique, between 605 and 612 m.

Figures

Fig. 7. Munida micra sp. nov., holotype, ♂, 3.7 mm (MNHN-IU-2008-10229), Mozambique. 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. Left P2, lateral view. G. Dactylus of left P2, lateral view. H. Left P3, lateral view. I. Right P4, lateral view. Scale bar: A–B, E–F, H–I = 1.0 mm; C–D, G = 0.5 mm.

Fig. 12. Dorsal view. Colours in life. A. Munida limula Macpherson & Baba, 1993, ♂, 3.4 mm, Madagascar, ATIMO VATAE, Stn TP12. B. Munida mesembria sp. nov., paratype, ♀, 6.5 mm, Mozambique, MAINBAZA, Stn CP3130. C. Munida micra sp. nov., holotype, ♂, 3.7 mm, Mozambique, MAINBAZA, Stn CC3165. D. Munida muscae Macpherson & de Saint Laurent, 2002, ♂, 3.2 mm, Madagascar, MIRIKY, Stn DW3179.