Eumunida spiridonovi, 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 : 4-6

Eumunida spiridonovi sp. nov.

urn:lsid:zoobank.org:act:F35484E7-1218-4FF5-AACE-8E2085E35C85

Fig. 1

Etymology

Named for Vassily Spiridonov, for his friendship and for making available this interesting material for study.

Type material

Holotype

WEST INDIAN OCEAN : ♀, 11.0 mm, E of Somalia, R/V Akademik Karchatov, Cruise 36, Stn 3781, 1°01.9′ N, 56°33.6′ E, 1170–1300 m, 5 May 1983 ( MNHN-IU-2016-8715 ).

Paratypes

WEST INDIAN OCEAN: 1 ♂, 15.2 mm, E of Somalia, R / V Akademik Karchatov, Cruise 36, Stn 3779, 1°06.5′ N, 56°28.7′ E, 1280–1380 m, 4 May 1983 (MNHN-IU-2016-8714); 3 ♂♂, 8.5–11.9 mm, same data as for holotype ( ZMM).

Description

CARAPACE.Slightly wider than long,eXclusive of rostrum.Gastric region well defined, moderately conveX; 3 small hepatic spines on each side, first spine near base of outer supraocular spine, larger than other two. Cervical groove and its posterior branch distinctly marked; without grooves separating cardiac and branchial areas. Dorsal surface as illustrated; anterior half without ridges, with weak and minute setose scales; posterior half (cardiac and posterior branchial areas) without transverse ridges, with some setose scales and numerous short setae. Lateral margins convex, armed with 9 spines, one strong anterolateral spine, followed by 1 minute spine at base, 2 spines anterior to posterior branch of cervical groove, and 5 spines decreasing in size posteriorly; greatest width measured between penultimate lateral spines; first spine well developed, subequal to third spine, and reaching sinus between supraocular spines. Distal spine in pterygostomian area. Rostrum sharply spiniform, about one-half of remaining carapace; inner supraocular spine terminating in two-thirds of length of rostrum, longer than outer supraocular.

STERNUM. Sternal plastron medially concave; anterior margin of sternite 3 with 2 median blunt processes; sternite 4 unarmed, granulated, with setiferous transverse ridges.

ABDOMEN. Second abdominal segment as illustrated; with 3 transverse ridges, and some short striae.

EYES. Short, cornea moderately dilated, exceeding end of outer supraocular spine.

ANTENNA. Article 1 with one short distolateral spine, distolateral spine of article 2 strong, not reaching mid-length of scaphocerite, article 3 with long distal spine, nearly reaching end of article 5; article 4 with strong dorsomesial spine reaching midlength of article 5, one short distolateral spine; article 5 with 3 strong spines distally (dorsal, mesial and lateral); scaphocerite spiniform, slender, exceeding base of article 5. Article 4 1.5 times length of article 2, and more than twice as long as broad.

MXP3. Merus of third maXilliped with minute spine on eXtensor and fleXor margin; ischium with crista dentata with 8–9 denticles.

P1. Subcylindrical, 4.6–4.8 times as long as carapace, excluding rostrum. Ischium with moderate-sized ventral spine; merus squamate, slightly more than twice carapace length, armed with 3 rows of spines (dorsolateral, dorsal, and dorsomesial, 1 additional ventral row of small spines in largest specimen); dorsomesial row composed of large and small spines regularly alternated. Carpus squamate, with 2 distal spines (3 spines in left P1 of holotype). Palm 1.5–1.7 times length of finger, slender, with few long uniramous setae, unarmed; without pad on ventral surface of palm. Fingers not gapping, furnished with relatively long coarse setae; opposable margins as illustrated.

P2–4. Similar, squamate, sparsely furnished with long coarse setae. P2 merus 1.1–1.2 times as long as propodus, with spines of different size on eXtensor margin, one strong distal spine on eXtensor and fleXor borders; carpus with some acute spines on eXtensor border, ultimate largest; propodus smooth on eXtensor margin, armed with 10–12 spinelets along fleXor border, and one distal fiXed spine; dactylus half propodus length, with 8–10 movable spinules along fleXor border. P3 similar to P2, but merus slightly shorter, and propodus similar in length. P4 merus 4.5 times as long as high, slightly shorter than propodus, armed with some spines in middle of dorsolateral face; propodus 9 times as long as high, with 12 spinules along fleXor margin; dactylus 0.5 propodus length, with 8–9 spinules along fleXor margin.

GENETIC DATA. Not available.

Remarks

The closest relative is E. debilistriata Baba, 1977 , from the Midway Islands. Both species have the dorsal carapace surface feebly striated, the anterior margin of the thoracic sternite 4 unarmed, and without a ventral pad on the P1 palm. However, the new species is readily distinguishable from E. debilistriata by the armature of the P1 carpus (with numerous spines in E. debilistriata and only 2–3 in the new species) and palm (with numerous mesial spines in E. debilistriata and unarmed in the new species). Furthermore, the extensor margin of the P2 propodus has some spines in E. debilistriata , whereas these spines are absent in E. spiridonovi sp. nov.

Distribution

Western Indian Ocean, east of Somalia, between 1170 and 1380 m.

Figures

Fig. 1. Eumunida spiridonovi sp. nov., holotype, ♀, 11.0 mm (MNHN-IU-2016-8715), East of Somalia. A. Carapace, dorsal view. B. Abdomen, dorsal view. C. Sternal plastron, sternites 3 and 4. D. Left antenna and antennula, ventral view. E. Right Mxp3. F. Right P1 merus, dorsal view. G. Right P1 carpus and distal part of merus, ventral view. H. Right P1 palm and fingers, dorsal view. I. Right P1 distal part of palm and fingers, ventral view. J. Right P2. Scale bar: A–C, G, I–J = 2.0 mm; D–E = 1 m; F, H = 0.5 mm.