Leiogalathea achates, Rodríguez-Flores & Macpherson & Machordom, 2019

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 : 207-211

Leiogalathea achates n. sp.

( Figs. 1 , 10A , 21A )

Liogalathea laevirostris .— Baba, 1990: 962 (misspelling).

Type material. Holotype: Mayotte-Glorieuses islands . BIOMAGLO Stn DW4853 , 13°00'S, 44°56'E, 665–669 m, 3 February 2017: ov. F 3.6 mm (MNHN-IU-2016-7125).

Paratypes: Madagascar. “Vauban” CREVETTIERE 1972 Stn CH 37, 12°51'S, 48°06.3'E, 675–705 m, 14 September 1972: 1 ov. F 7.1 mm (MNHN-IU-2016-423) .

Seychelles W Indian, R / V Akademik Karchatov, P.P. Shirshov Institute of Oceanology of Russian Academy of Sciences, Stn 36 (3731), 06°11.5'S, 54°21.3'E, 560–640 m, 28 March 1983: 1 ov. F 4.5 mm (MNHN-IU-2014- 13705) .

Mayotte-Glorieuses islands. BIOMAGLO Stn DW4842, 12°23'S, 43°33'E, 420– 388m, 29 January 2017: 1 M 4.2 mm, 1 F 3.9 mm (MNHN-IU-2016-3213).—Stn DW4851, 3°01'S, 44°57'E, 660–664 m, 3 February 2017: 1 F 5–5.2 mm, 3 ov. F 4.9–5.2 mm, 2 F 4.0– 4.9 mm (MNHN-IU-2016-8833).—Stn DW4863, 12°30'S, 44°56'E, 606– 610 m, 6 February 2017: 2 M 5–6.5 mm (MNHN-IU-2016-8832).—Stn DW4864, 12°56'S, 45°15'E, 455–487 m, 7 February 2017: 1 ov. F 5.8 mm (MNHN-IU-2016-3203), 1 F 3.9 mm (MNHN-IU-2016-3204).—Stn DW4866, 12°58'S, 45°15'E, 687–712 m, 7 February 2017: 1 F 4.8 mm (MNHN-IU-2016-3205).—Stn DW4872, 12°44'S, 45°19'E, 502–568 m, 8 February 2017: 1 M 3.8 mm, 1 ov. F 4.9 mm, 1 F 4.2 mm (MNHN-IU-2016-8831).—Stn DW4873, 12°42'S, 45°22'E, 795–1033 m, 8 February 2017: 1 M 6.0 mm (MNHN-IU- 2016-2201), 1 M 7 mm (MNHN-IU-2016-8834), 1 M 7.2 mm (MNHN-IU-2016-3207), 2 ov. F 4.8–4.9 mm (MNHN-IU-2016-3208).—Stn DW4874, 12°42'S, 45°19'E, 706–887 m, 9 February 2017: 1 M 6.1 mm (MNHN-IU-2016-3206).—Stn DW4875, 12°44'S, 45°20'E, 617–664 m, 9 February 2017: 1 F 3.9 mm (MNHN-IU-2016-3508).—Stn CP4876, 12°43'S, 45°18'E, 452–462 m, 9 February 2017: 1 M 5.2 mm (MNHN-IU-2016-3202).

Etymology. From the name Achates, a Trojan and a personal friend of Aeneas in the Aeneid. The name is considered a substantive in apposition.

Description. Carapace: 1.2–1.3 × as long as broad. Mid-transverse ridge usually interrupted, preceded by shallow cervical groove, followed by 5 interrupted transverse ridges. Lateral margins slightly convex, with 2 or 3 spines: first spine anterolateral, well-developed; hepatic margin unarmed; 1 well-developed spine on anterior branchial margin, 0–1 spine on posterior branchial margin. Rostrum horizontal, dorsally slightly concave, 1.4–1.5 × as long as broad, length 0.4 × and breadth 0.2–0.3 × that of carapace; lateral margin armed with 2 or 3 welldeveloped proximal teeth and 1 or 2 minute distal teeth.

Sternum: Sternite 3 acutely broad, 4.0–4.5 × as wide as long, anterolaterally produced, anterior margin with a median shallow notch flanked by 2 shallow lobes. Sternite 4 narrowly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 2.4 × as wide as long, 4.7 × that of sternite 3.

Abdomen: Tergite 2 with 2 elevated transverse ridges, tergites 3–4 each with transverse ridge, tergites 5–6 smooth; tergite 6 with transverse posteromedian margin.

Eye: Ocular peduncle slightly longer than wide; cornea subglobular, maximum corneal diameter 0.8 × rostrum width, as wide as eyestalk.

Antennule: Article 1 with distomesial angle unarmed; lateral margin smooth.

Antenna: Article 1 with distomesial spine not reaching end of article 2; article 2 with distomesial spine longer than distolateral spine and nearly reaching end of article 3; articles 3 and 4 unarmed.

Mxp3: Ischium as long as merus measured along extensor margin; flexor margin sharply ridged, terminating in small spine; extensor margin unarmed; crista dentata finely denticulate; merus having flexor margin with 1 strong median spine, extensor margin with 1 distal spine.

P1: 2.4–2.6 (males), 2.1 (females) × carapace length, with numerous short striae, and covered by uniramous long setae on merus to dactylus. Merus 0.9 length of carapace, twice as long as carpus, with strong mesial and distal spines, and scattered dorsal spines. Carpus 0.8 × shorter than palm, 1.6 × as long as broad, dorsal surface with scattered spines, mesial and lateral margins with 1 or 2 strong spines. Palm 1.6 × as long as broad, mesial and lateral margins with spines in irregular longitudinal rows, dorsal surface unarmed. Fingers 1.1 × as long as palm; fixed finger with several proximal lateral spines; movable finger with proximal mesial spine.

P2–4: Moderately slender, somewhat compressed laterally, with sparse short setiferous striae on dorsal surface, and sparse long thick setae on ischium to dactylus. Meri successively shorter posteriorly (P3 merus 0.8 × length of P2 merus, P4 merus 0.9 × length of P3 merus). P2 merus 0.6 × carapace length, 4.6 × as long as broad, 1.1 × as long as P2 propodus; P3 merus 3.9 × as long as broad, 1.1 × as long as P3 propodus; P4 merus 3.6 × as long as broad, as long as P4 propodus; extensor margins with row of 7 or 8 proximally diminishing spines distinct on P2; unarmed or obsolescent on P3, absent on P4; lateral surface unarmed; flexor margin with well-developed distal spine proximally followed by several scattered 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 6.0–6.5 × as long as broad on P2–4, flexor margin with 4–6 movable spinules. Dactyli 0.7–0.8 length of propodi; distal claw short, moderately curved; flexor margin nearly straight, with 7 or 8 small teeth along entire margin decreasing in size proximally, each with slender movable spinule, ultimate tooth equidistant between base of distal claw and penultimate tooth.

Colour in life. Ground colour pale yellow, orange or whitish. Carapace and abdominal somites 2–3 pale orange, posterior part of abdomen translucent. Ocular peduncles covered by small brown spots. P1 totally orange with some white bands. P2–4 whitish with orange or pale orange bands, white to translucent at tips.

L. L. L. L. L. L. L. L. L. L. L. L. L. L. L.

achates agassizii amata anchises ascanius camilla creusa dido evander juturna pallas paris priam sinon turnus

n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp. n. sp.

L. achates n. sp. 0.4, 0.3 5.4 6.7 5.9 3.4 6.6 - 5.9 0.8 5.5 6.9 6.2 7.2 5.0 5.7

L. agassizii 12.7 0.9, 0.0 6.0 5.5 5.5 7.7 - 6.0 5.5 6.9 6.2 7.6 8.4 6.8 5.7

L. amata n. sp. 11.6 12.0 -, 0.0 6.0 6.3 6.9 - 7.3 6.8 5.4 1.4 5.7 6.5 6.4 7.1

L. anchises n. sp. 13.3 13.7 14.3 0.2, 0.0 5.7 7.4 - 5.0 6.0 6.4 6.7 6.8 6.8 6.0 4.7

L. ascanius n. sp. 11.9 13.1 15.9 15.4 0.7, 0.0 6.9 - 6.8 3.4 5.6 6.0 5.7 7.3 6.0 6.5

L. camilla n. sp. 13.6 12.6 13.5 15.6 15.4 0.0, 0.3 - 7.4 6.7 3.4 7.1 4.0 5.6 6.7 7.4

L. creusa n. sp. 13.7 12.8 13.1 7.1 15.0 15.9 -, - - - - - - - - -

L. dido n. sp. 14.9 11.7 12.6 14.3 15.8 12.9 12.6 0.0, 0.0 6.0 6.9 7.5 7.6 8.9 6.5 0.3

L. evander n. sp. 4.4 11.3 12.1 13.3 11.3 13.6 13.1 14.2 0.5, 0.0 5.6 7.0 6.3 7.3 5.2 5.7

L. juturna n. sp. 13.3 14.1 15.0 16.0 15.0 11.9 15.5 14.9 13.0 1.1, 0.3 5.5 1.4 4.0 5.1 6.7

L. pallas n. sp. 11.9 12.0 4.1 14.2 14.8 13.3 13.8 12.9 12.0 14.6 0.4, 0.1 6.2 6.7 6.9 7.2

L. paris n. sp. 12.9 11.1 12.3 15.5 14.0 11.3 13.8 14.0 12.2 7.2 13.2 0.1, 0.0 4.7 5.7 7.3

L. priam n. sp. 12.1 12.5 12.9 15.4 14.4 12.0 15.5 13.9 11.9 10.3 13.4 9.0 0.0, 0.0 6.1 8.6

L. sinon n. sp. 10.7 11.8 12.9 13.8 11.7 13.1 14.2 13.3 10.8 12.7 13.0 11.9 11.5 -, 0.5 6.3

L. turnus n. sp. 14.9 12.8 14.2 13.6 15.4 12.6 13.1 3.5 13.9 14.5 14.1 12.9 15.3 13.5 -, - Genetic data. COI and 16S ( Table 2). Distribution. Madagascar, Channel of Mozambique (Mayotte-Glorieuses islands) and Seychelles, on quartzcalcareous sand, from 388 to 1033 m.

Remarks. Leiogalathea achates belongs to the group of species having the hepatic margin of the carapace unarmed and the branchial margin of the carapace armed with 1 or 2 spines. The closest relative is L. evander from French Polynesia, Philippines and Papua New Guinea (see below, under the Remarks of that species). The specimen examined from the Seychelles shows some morphological inconsistences in the pattern of striae of the carapace, shape and armature of the rostrum, with most of the pereiopods lost. Additional material from this area would be desirable in order to confirm its taxonomic status.

Figures

FIGURE 1. Leiogalathea achates n. sp., A, C–I, holotype, ov. F 3.6 mm, Mayotte-Glorieuses Islands (MNHN-IU-2016-7125); B, paratype, M 7.0 mm, Mayotte-Glorieuses Islands (MNHN-IU-2016-8834). A, carapace and abdomen, dorsal view. B, carapace, right side, dorsal view. C, Sternites 3–4. D, cephalic region, showing antennular and antennal peduncles, ventral view. E, right Mxp3 ischium and merus, lateral view. F, right P1, dorsal view. G, right P2, lateral view. H, right P3, lateral view. I. right P4, lateral view. Scales: A, B, F–I = 1.0 mm; C–E = 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.