Munida tetracantha, 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 : 28-31

Munida tetracantha sp. nov.

urn:lsid:zoobank.org:act:DE739D23-1F10-4C44-B75E-3CA111098F20

Figs 9 , 13C

Etymology

From the Greek, tetra, four and acantha, spine, in relation to the four lateral branchial spines of the carapace.

Type material

Holotype

MADAGASCAR: ♂, 6.6 mm, ATIMO VATAE, Stn DW3522, 24°23.85′ S, 47°32.12′ E, 154–168 m, 1 May 2010 ( MNHN-IU-2014-13474 ).

Paratypes

MADAGASCAR: 2 ov. ♀♀, 4.0– 5.8 mm, MIRIKY, Stn CP3260, 15°35′ S, 45°45′ E, 179–193 m, 10 Jul. 2009 (MNHN-IU-2014-13601); 1 ♂, 3.0 mm, ATIMO VATAE, Stn CP3546, 25°23.21′ S, 46°42.57′ E, 84–85 m, 4 May 2010 (MNHN-IU- 2010-2726); 1 ov. ♀, 3.7 mm, ATIMO VATAE, Stn CP3549, 25°16.87′ S, 46°31.80′ E, 53–54 m, 4 May 2010 (MNHN-IU-2014-13602).

MOZAMBIQUE: 1 ♂, 7.4 mm, MAINBAZA, Stn CP3131, 25º54.62′ S, 33º06.91′ E, 193–194 m, 9 Apr. 2009 (MNHN-IU-2008-10221); 2 ♂♂, 6.3–7.5 mm, 1 ov. ♀, 5.6 mm, MAINBAZA, Stn CC 3151, 19°32.80′ S, 36°45.96′ E, 352–357 m, 13 Apr. 2009 (MNHN-IU-2014-13598); 2 ♂♂, 4.0– 4.2 mm, MAINBAZA, Stn CC 3159, 23º53.80′ S, 35º37.58′ E, 148–152 m, 15 Apr. 2009 (MNHN- IU-2014-13599).

FRANCE: 1 ov. ♀, 5.2 mm, La Réunion Island, MD 32, Stn HY75, 21º21.6′ S, 55º26.7′ E, 380–465 m, 24 Aug. 1982 (MNHN-IU-2014-13600).

Description

CARAPACE. 1.2–1.3 times as long as broad, with few secondary striae between main transverse ridges. Ridges with very short non-iridescent setae and few scattered long non-plumose setae. Few small scales on intestinal region. Gastric region with 4–5 pairs of epigastric spines, longest pair behind supraocular spines. One parahepatic, one branchial dorsal and one postcervical spine on each side. Frontal margins slightly oblique. Lateral margins slightly convex. First lateral spine at anterolateral angle, long, not reaching level of sinus between rostrum and supraocular spines; second spine in front of anterior branch of cervical groove and less than half length of preceding one. Branchial margins with four spines. Rostrum spiniform, about 0.5–0.6 times length of remaining carapace, horizontal. Supraocular spines barely reaching midlength of rostrum and not reaching end of corneae, subparalell, directed slightly upwards ( Fig. 2A ).

STERNUM. Granules on each posterolateral part of sternite 7. Surfaces of thoracic sternites smooth. Sternite 4 with anterior margin nearly transverse, broadly contiguous to sternite 3.

ABDOMEN. Anterior ridge of somite 2 with 9–10 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 0.3–0.4 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 clearly not exceeding distomesial spine.

ANTENNA. Article 1 with strong distomesial spine reaching distal margin of article 2. Article 2 with distomesial spine exceeding article 3, and not overreaching antennal peduncle; distolateral spine as long as distomesial. Article 3 unarmed.

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

P1. 2.5–2.8 times carapace length, with some finely setiferous scales, with long thick iridescent and nonplumose setae scattered on dorsal side and more numerous along mesial margin. Merus 0.9–1.0 length of carapace, 1.7 times as long as carpus, with some dorsal, mesial and a few distolateral spines. Carpus 1.0–1.1 length of palm, 1.7–1.8 times as long as broad; with rows of spines along mesial, dorsal and lateral sides. Palm 1.8 times as long as broad, with row of small dorsal spines; one row of spines along mesial and lateral spines. Fingers 1.2–1.3 length of palm; one row of spines along the lateral margin; one row of small spines along mesial margin.

P2–4. Moderately long and slender, with some long iridiscent setae along extensor margins of articles. P2 1.8–1.9 times carapace length. Meri shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.9 length of P3 merus); P2 merus 0.5–0.6 carapace length, 4.2–4.4 times as long as broad, as long as or slightly longer than P2 propodus; P3 merus 3.0 times as long as broad, as long as P3 propodus; P4 merus 3.8 times as long as broad, as long as P4 propodus. Extensor margins of meri with row of 6–8 proximally diminishing spines on P2–3, unarmed on P4, eXcept distal spine; fleXor margins distally with 1–2 spines followed proximally by several eminences; lateral sides unarmed. Carpi with 3–4 spines on extensor margin; lateral surface with several acute granules sub-paralleling eXtensor margin on P2–4; fleXor distal margin with small spine. Propodi 4.4 (P2–3)–3.8 (P4) times as long as broad; extensor margin unarmed; fleXor margin with 8–9 slender movable spines on P2–4. Dactyli slender, length 0.7–0.8 that of propodi; fleXor margin with 7 movable spinules along entire border, without a spinule at base of unguis; P2 dactylus 6 times as long as wide.

COLOUR. Carapace with pinkish-orange and yellow stripes, spines red; rostral and supraocular spines reddish, dorsally whitish. P1 with reddish and whitish bands, tip of fingers whitish; spines reddish. P2–4 mostly lost in photographed specimen, P4 merus with reddish and whitish bands.

GENETIC DATA. COI, see Table 1 .

Remarks

Munida tetracantha sp. nov. belongs to the group of species having three or four spines on the branchial lateral margins of the carapace, the lateral parts of the posterior thoracic sternites with granules, and spines on the anterior ridge of the second abdominal somite. The new species is closely related to M. barbeti Galil, 1999 from Mauritius ( Galil 1999), La Réunion, Madagascar and Aldabra ( Macpherson & de Saint Laurent 2002).

However, M. tetracantha sp. nov. is easily distinguished from M. barbeti by several characters:

– The distomesial spine of antennular article 1 is longer than the distolateral in M. barbeti , whereas it is shorter in the new species.

– The distomesial and distolateral spines of antennal article 2 overreach article 3 in the new species, whereas these spines fall short of the end of the third segment in M. barbeti .

– The first and second anterolateral spines of the carapace are subequal in M. barbeti , whereas the first spine is more than twice as long as the second spine in M. tetracantha sp. nov.

The new species is also close to M. gordoae Macpherson, 1994 , from New Caledonia, Vanuatu and adjacent waters ( Macpherson 1994, 2004). Both species have 4 spines on each branchial margin of the carapace and granules on each posterolateral part of sternite 7. However, this species can be distinguished from M. tetracantha sp. nov. by the following characters:

– The P1 fiXed and movable fingers have spines along the entire lateral and mesial margins, in M. tetracantha sp. nov., whereas these spines are on the proximal half of each margin in M. gordoae .

– The P2–4 meri are longer and more slender in M. gordoae than in the new species. The P2 merus is nearly 6 times as long as high in M. gordoae , but ca 4 times in M. tetracantha sp. nov.

Molecular data showed that Munida tetracantha sp. nov. greatly differed with respect to other species of the area, like M. nesiotes , M. mesembria sp. nov. or M. austrina sp. nov. (p COI> 16%). In fact, the closest species was M. gordoae from the SW Pacific, with a high COI divergence of 9%, suggesting that the morphological characters shared by both species (e.g., 4 spines on each branchial margin of the carapace and granules on each posterolateral part of sternite 7) can have a phylogenetic value.

Distribution

Mozambique, Madagascar, La Réunion Island, between 53 and 465 m.

Figures

Fig. 9. Munida tetracantha sp. nov., holotype, ♂, 6.6 mm (MNHN-IU-2014-13474), 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. Right P4, lateral view. Scale bar: A, E–F, H = 2.0 mm; B–D, G = 1.0 mm.

Fig. 13. Dorsal view. Colours in life. A. Munida nesiotes Macpherson, 1999, ov. ♀, 8.5 mm, Mozambique, MAINBAZA, Stn CP3143. B. Munida shaula Macpherson & de Saint Laurent, 2002, ov. ♀, 12.4 mm, Mozambique, MAINBAZA, Stn CC3151. C. Munida tetracantha sp. nov., paratype, ♂, 7.4 mm, Mozambique, MAINBAZA, Stn CP3131. D. Paramunida marionis Cabezas et al., 2011, ♀, 6.0 mm, Mozambique, MAINBAZA, Stn CP3143.

Fig. 2. Munida austrina sp. nov., holotype, ♀, 4.6 mm (MNHN-IU-2014-13478), 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. Right P1, dorsal view. F. Right P2, lateral view. G. Dactylus of right P2, lateral view. H. Right P3, lateral view. I. Right P4, lateral view. Scale bar: A, E–F, H–I = 1.0 mm; B–D, G = 0.5 mm.