Munida mesembria, 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 : 18-22

Munida mesembria sp. nov.

urn:lsid:zoobank.org:act:61452888-4764-40BB-8946-69DC998BC123

Figs 6 , 12B

Etymology

From the Greek, mesembria , south, in relation to the area of collection of the species.

Type material

Holotype

MOZAMBIQUE: ♂, 7.7 mm, MAINBAZA, Stn CP3144, 23°32.14′ S, 35°41.66′ E, 171–180 m, 11 Apr. 2009 ( MNHN-IU-2014-13477 ).

Paratypes

MOZAMBIQUE: 27 ♂♂, 4.6–9.7 mm, 22 ov. ♀♀, 5.5–8.2 mm, 5 ♀♀, 5.2–7.5 mm, MAINBAZA, Stn CP3130, 25°52.00′ S, 33°07.05′ E, 112–127 m, 9 Apr. 2009 (MNHN-IU-2014-19214, MNHN- IU-2008-10219); 1 ov. ♀, 6.4 mm, MAINBAZA, Stn CP3131, 25°54.62′ S, 33°06.91′ E, 193–194 m, 9 Apr. 2009 (MNHN-IU-2014-13523); 1 ov. ♀, 7.4 mm, same data as previous (MNHN-IU-2008-10218); 10 ♂♂, 3.6–9.0 mm, 2 ♀♀, 5.6–6.4 mm, same data as for holotype (MNHN-IU-2014-19215), 1 ♂, 8.0 mm, same data as for holotype (MNHN-IU-2008-10225); 20 ♂♂, 6.7–11.0 mm, 17 ov. ♀♀, 7.0– 8.4 mm, 3 ♀♀ 6.4–6.5 mm, MAINBAZA, Stn CC3151, 19°32.80′ S, 36°45.96′ E, 352–357 m, 13 Apr. 2009 (MNHN-IU-2014-19258); 1 ♂, 4.6 mm, 11 ♀♀, 2.7–5.0 mm, MAINBAZA, Stn CC3159, 23°53.80′ S, 35°37.58′ E, 148–152 m, 15 Apr. 2009 (MNHN-IU-2014-13522).

Description

CARAPACE. Slightly longer than broad, with some secondary striae between main transverse ridges. Dorsal ridges with very short non-iridescent setae and few scattered long iridescent and non-plumose setae. Gastric region with 5–6 pairs of epigastric spines, longest pair behind supraocular spines; row of 2–3 small median epigastric spines behind rostral spine. One parahepatic, one branchial dorsal and one postcervical spine on each side. Frontal margins transverse. Lateral margins slightly convex. First lateral spine at anterolateral angle, moderately long, nearly reaching level of sinus between rostrum and supraocular spines; 2–3 small spines in front of anterior branch of cervical groove; end of anterior branch of cervical groove with tuft of iridescent setae. Branchial margins with five 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, slightly divergent, directed slightly upwards.

STERNUM. Surface of thoracic sternite 4 with numerous striae; sternites 5 and 6 with some short striae on each lateral side; distal margin of sternite 4 nearly transverse, broadly contiguous to sternite 3.

ABDOMEN. Anterior ridge of somite 2 unarmed; somites 2–4 each with 5–6 uninterrupted transverse ridges on tergite behind anterior ridge; somite 4 smooth or with minute setose scales on tergite; somites 5 and 6 with few transverse ridges, 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, distomesial longer than distolateral spine; two lateral spines, distal much longer than proximal and exceeding distomesial spine.

ANTENNA. Article 1 with strong distomesial spine barely reaching distal margin of article 3; surface with some short striae. Article 2 with distomesial spine strong, exceeding antennal peduncle; distolateral spine slightly exceeding article 3. Article 3 unarmed.

MXP3. Ischium with long distal spine on fleXor and eXtensor margins. Merus slightly shorter than ischium; fleXor margin with 3 well developed spines, proXimal stronger than others; eXtensor margin with distal spine. Carpus unarmed.

P1. 2.1–2.5 (females), 2.6–3.4 (males) times carapace length, with few finely setiferous scales, with very dense long iridescent and plumose setae along mesial margins of merus and carpus; some scattered long setae on dorsal surfaces of articles. Merus 0.9–1.0 length of carapace, 1.7 times as long as carpus, with some dorsal spines; distal spines strong, distomesial spine clearly not reaching midlength of carpus. Carpus 0.8 length of palm, 1.7 times as long as broad, with spines along mesial and dorsal sides. Palm 1.9–2.0 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 4–5 spines along lateral margin; movable finger with one basal spine and 2–3 subdistal spines.

P2–4. Moderately long and slender, with dense plumose setae and few long iridiscent setae along extensor margin of articles, with finely setiferous scales on surface. P2 2.1 times carapace length. Meri shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.8 carapace length, 5.5 times as long as broad, 1.4–1.5 times as long as P2 propodus; P3 merus 5.0 times as long as broad, 1.2–1.3 times as long as P3 propodus; P4 merus 4 times as long as broad, as long as P4 propodus. Extensor margins of meri with row of 8–11 proximally diminishing spines on P2–3, unarmed on P4, eXcept distal spine; fleXor margins distally with 1–3 spines followed proXimally by several eminences; lateral sides unarmed. Carpi with 2–3 spines on extensor margin; lateral surface with several granules sub-paralleling eXtensor margin on P2–4; fleXor margin with distal spine. P2–4 propodi 4.5–5.0 (P2– 3)–4.5 (P4) times as long as broad; eXtensor margin unarmed; fleXor margin with 9–10 slender movable spines on P2–4. Dactyli slender, length 0.7–0.8 that of propodi; fleXor margin with 7–9 movable spinules along entire border, without a spinule at base of unguis; P2 dactylus 6 times as long as wide.

COLOUR. Ground colour orange, with some red patches. Rostrum and supraocular spines orange. P1 orange, with reddish bands; fingers orange, with some white and red spots. P2–4 orange, with reddish transverse bands.

GENETIC DATA. COI, 16S see Table 1 .

Remarks

Munida mesembria sp. nov. belongs to the group of species having five spines on the branchial lateral margins of the carapace, thoracic sternites with short striae, well developed eyes, the anterior ridge of the second abdominal somite unarmed and the distomesial spine of the antennal article 1 longer than the distolateral. The new species is closely related to M. austrina sp. nov. (see above).

M. mesembria sp. nov. is easily distinguished from M. austrina sp. nov. by several characters:

– The surface of the thoracic sternite 4 has numerous striae in M. mesembria sp. nov. These striae are scarce in M. austrina sp. nov.

– The distomesial spine of the article 2 of the antennal peduncle clearly overreaches the end of the antennal peduncle in M. mesembria sp. nov., whereas this spine ends at the distal border of article 4 in M. austrina sp. nov.

– The P1 has dense long thick iridescent and plumose setae along the mesial margins of the merus and carpus in M. mesembria sp. nov., whereas scarcely so in M. austrina sp. nov.

Munida mesembria sp. nov. and M. austrina sp. nov. showed a COI divergence of around 9%, but values in the range of 6.5–8.2% were found with respect to species such as M. armilla , M. proto Macpherson, 1994 , M. spilota Macpherson, 1994 , M. notata Macpherson, 1994 and M. tyche Macpherson, 1994 from the SW Pacific ( Macpherson 1994). Lower values were found for 16S, only 1.8–3% with respect to M. notata .

Munida mesembria sp. nov. and M. notata are easily distinguished by several characters:

– The surface of the thoracic sternite 4 has numerous striae in M. mesembria sp. nov. These striae are scarce in M. notata .

– The P1 has very dense long iridescent and plumose setae along the mesial margins of the merus and carpus in M. mesembria sp. nov., whereas these setae are clearly less dense in M. notata .

- The P1 movable finger has one basal spine and 2–3 subdistal spines along the mesial margin in M. mesembria sp. nov., whereas this margin has a row of numerous spines in M. notata .

Distribution

Mozambique, at 112– 357 m.

Figures

Fig. 6. Munida mesembria sp. nov., holotype, ♂, 7.7 mm (MNHN-IU-2014-13477), 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. Left P3, lateral view. I. Right P4, lateral view. Scale bar: A, E–F, H–I = 2.0 mm; B–D, G = 1.0 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.