Leiogalathea agassizii (A. Milne Edwards, 1880 )

Rodríguez-Flores, Paula C., Macpherson, Enrique & Machordom, Annie, 2019, Revision of the squat lobsters of the genus Leiogalathea Baba, 1969 (Crustacea, Decapoda, Munidopsidae) with the description of 15 new species, Zootaxa 4560 (2), pp. 201-256 : 213-215

Leiogalathea agassizii (A. Milne Edwards, 1880)

( Figs. 3 , 10C , 21B )

Galathea agassizii —A. Milne Edwards 1880: 47.—A. Milne Edwards & Bouvier 1894: 252 (key).—A. Milne Edwards & Bouvier 1897: 17, pl. 1, figs 6–15.— Chace, 1942: 30. Leiogalathea agassizii — Baba et al. 2008: 83 (compilation, in part).— Poupin & Corbari 2016: 44, fig. 10i.

Type material. Syntypes: Barbados. USCSS Blake Expeditions Stn 283, 13°05'05''N, 59°40'50''W, 432 m, 0 7 March 1879: 4 ov. F 4.6–6.8 mm (MCZ-CRU-4708) .

Other material examined. Florida. MSM 20 /4, Cruise SAM ID 2627 Stn163 34–1, 26°20.198’N, 84°45.672’W, 522 m, 27 March 2012, on live Enallopsammia sp.: 2 F 6.9– 5.4 mm (SMF51247).

Guadeloupe Island. KARUBENTHOS 2015 Stn DW4510 , 16°15'N, 61°51'W, 660–690 m, 0 7 June 2015: 1 M 6.7 mm (MNHN-IU-2013-18858).—Stn DW4511 , 16°14'N, 61°52'W, 660– 630 m, 0 8 June 2015: 1 F 4.1 mm (MNHN-IU-2013-18894) .

Description. Carapace: 1.2 × as long as broad. Mid-transverse ridge usually interrupted, preceded by shallow cervical groove, followed by 4 interrupted transverse ridges. Lateral margins slightly convex, with 5 or 6 spines: first spine anterolateral, well-developed; spine on hepatic margin smaller than first spine; 2 well-developed spines on anterior branchial margin usually decreasing in size posteriorly; 1 or 2 small spines on posterior branchial margin. Rostrum horizontal, slightly concave dorsally, 1.3–1.4 × as long as broad, length 0.4 × and breadth 0.3 × that of carapace; lateral margin with 2 well-developed proximal teeth, distal margin serrated.

Sternum: Sternite 3 acutely broad, 3.7–4.0 × as wide as long, anterolaterally somewhat produced, anterior margin serrated, straight, with a median shallow notch. Sternite 4 broadly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 2.4 × that of sternite 3, 2 × as wide as long.

Abdomen: Tergites 2–3 each with 1 or 2 elevated transverse ridges, tergite 4 with or without transverse ridge, tergites 5–6 smooth; tergite 6 with transverse posteromedian margin.

Eye: Ocular peduncle slightly longer than broad, cornea subglobular, maximum corneal diameter 0.7 × rostrum width, cornea as wide as eyestalk.

Antennule: Article 1 with distomesial angle unarmed; lateral margin serrated along distal part.

Antenna: Article 1 with strong distomesial spine nearly reaching end of article 2; article 2 with strong distomesial spine, longer than distolateral spine and reaching end of peduncle, distolateral spine overreaching article 3; articles 3 and 4 unarmed.

Mxp3: Ischium as long as merus measured along extensor margin; flexor margin sharply ridged, terminating in well-developed spine; extensor margin unarmed; crista dentata finely denticulate; merus having flexor margin with 1 strong median spine and with or without minute distal spine, extensor margin with distal spine.

P1: 2.8 (males), 2.4–2.5 (females) × carapace length, with numerous short striae, and uniramous setae scattered on merus to dactylus. Merus 0.5–0.6 length of carapace, 2.3 × as long as carpus, with strong mesial spines, sparse small distal spines, and scattered dorsal spines. Carpus 0.7 × as long as palm, 1.3 × as long as broad, dorsal surface with several scattered spines, mesial margin with strong spine and several small spines, lateral margin unarmed. Palm 1.6 × as long as broad, armed with small spines in irregular longitudinal rows on mesial and lateral margins, dorsal surface unarmed. Fingers as long as or slightly shorter than palm; fixed finger with 2 lateral small proximal spines; movable finger with small mesial proximal spine.

P2–4: Moderately slender, somewhat compressed laterally, with short striae on dorsal surface, ischium to dactylus sparsely with long and thick setae. Meri successively shorter posteriorly (P2 merus as long as P3 merus, P4 merus 0.9 × length of P3). P2 merus 0.6 × carapace length, 5.6–5.8 × as long as broad, 1.2 × as long as P2 propodus; P3 merus 5.5 × as long as broad, 1.2 × as long as P3 propodus, P4 merus 5 × as long as broad, as long as P4 propodus; extensor margins with row of 7 or 8 proximally diminishing spines on P2–3, extensor margin unarmed on P4; lateral surface unarmed; flexor distal margin with well-developed distal spine and several additional projecting scales. Carpi with 2 or 3 spines on extensor margin on P2–3, unarmed on P4, lateral side smooth; flexor margin with small distal spine. Propodi 8.0–9.0 × as long as broad on P2–4, flexor margin with 4 or 5 movable spinules. Dactyli 0.5–0.6 × length of propodi; distal claw strong, moderately curved; flexor margin nearly straight, with 8–10 small teeth along entire margin decreasing in size proximally, each with slender movable spinule, ultimate tooth closer to base of distal claw than to penultimate tooth.

Colour. Ground colour pale yellow, orange or whitish. Carapace and anterior half of abdomen pale orange, posterior part of abdomen translucent; posterior half of carapace covered with reddish orange small spots. P1 totally orange, white at tip of fingers. P2–4 pale orange, white at tips (propodi and dactyli).

Genetic data. COI and 16S ( Table 2).

Distribution. Caribbean Sea: St Lucia and Barbados and north coast of Cuba at depths of 300– 897 m. The present material was collected in Florida and Guadeloupe Island, between 519 and 690 m.

Remarks. Leiogalathea agassizii belongs to the group of species having the hepatic margin of the carapace armed with a spine. The closest relative is L. aeneas from Northwest Africa and both species can be differentiated by the following characters:

The rostrum is slender in L. aeneas (1.6–1.8 × as long as wide), whereas it is 1.3–1.4 as long as wide in L. agassizii .

L. agassizii has usually three spines on branchial margin whereas this margin has usually four spines in L. aeneas .

Anterolateral angle of sternite 4 is denticulate in L. aeneas , whereas this angle is smooth in L. agassizii .

The P1 fixed finger is unarmed in L. aeneas , whereas there are several proximal spines in L. agassizii .

The P2–4 propodi in L. agassizii are moderately slender (more than 8 × as long as broad), whereas the propodi are moderately stout (less than 6 × longer than broad) in L. aeneas .

Leiogalathea agassizii also resembles L. ascanius from New Caledonia and Hunter and Mathew Islands (see below under the Remarks of that species).

Figures

FIGURE 3. Leiogalathea agassizii (A. Milne Edwards, 1880), A–D, F–H, F 6.9 mm, Florida (SMF51247); E, M 6.7 mm, Guadeloupe (MNHN-IU-2013-18858). A, carapace and abdomen, dorsal view. B, sternites 3–4. C, cephalic region, showing antennular and antennal peduncles, ventral view. D, right Mxp3 ischium and merus, lateral view. E, left P1, dorsal view. F, right P2, lateral view. G, dactylus of right P2, lateral view. H, right P3, lateral view. Scales: A, F, H = 1.0 mm; E = 2 mm; B–D, G = 0.5 mm.

FIGURE 10. Rostrum, and ocular peduncle, dorsal view. A, Leiogalathea achates n. sp., holotype, ov. F 3.6 mm (MNHN-IU- 2016-7125). B, L. aeneas n. sp., holotype, F 7.6 mm (SMF51246). C, L. agassizii (A. Milne Edwards, 1880), F 6.9 mm (SMF51247), Florida. D, L. amata n. sp., holotype, F 3.6 mm (MNHN-IU-2014-13779). E, L. anchises n. sp., holotype, F 6.4 mm (MNHN-IU-2014-13786). F, L. ascanius n. sp., holotype, M 5.9 mm (MNHN-IU-2013-17425). G, L. camilla n. sp., holotype, M 3.0 mm, (MNHN-IU-2014-13728). H, L. creusa n. sp., holotype, F 5.0 mm (MNHN-IU-2014-13716). I, L. dido n. sp., holotype, ov. F 9.8 mm (MNHN-IU-2013-17431). Scale = 1 mm.

FIGURE 21. A, Leiogalathea achates n. sp., holotype, ovigerous female 3.6 mm (MNHN-IU-2016-7125), Mayotte- Glorieuses islands. B, Leiogalathea agassizii, male 6.7 mm (MNHN-IU-2013-18858), Guadeloupe Island. C, Leiogalathea evander n. sp., male 5.9 mm (MNHN-IU-2015-146), Papua New Guinea. D, Leiogalathea pallas n. sp., male 8.3 mm (MNHN- IU-2014-13775), Vanuatu. E, Leiogalathea paris n. sp., female 5.4 mm (MNHN-IU-2013-1727), New Caledonia. F, Leiogalathea priam n. sp., male 5.2 mm (MNHN-IU-2015-212), Papua New Guinea. Dorsal view.