Leiogalathea turnus, 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 : 249-252

Leiogalathea turnus n. sp.

( Figs. 11I , 20 )

Type material. Holotype: New Caledonia. NORFOLK 2 Stn DW2046 , 23°43.87'S, 168°01.03'E, 333–375 m, 23 October 2003: M 8.0 mm (MNHN-IU-2014-13744).

Etymology. From the name Turnus, Aeneas ’s major antagonist among mortals in the Aeneid. The name is considered a substantive in apposition.

Description. Carapace: 1.2 × as long as broad. Mid-transverse ridge interrupted, preceded by cervical groove, followed by 5 or 6 interrupted transverse ridges. Lateral margins convex, with 7 or 8 spines: first spine anterolateral, well-developed; spine on hepatic margin; 3 well-developed spines on anterior branchial margin decreasing in size posteriorly; and 2 or 3 spines on posterior branchial margin. Rostrum horizontal, dorsally flattish or slightly concave, 1.3–1.5 × as long as broad, length and breadth 0.3 × that of carapace; lateral margin with 3 teeth, decreasing in size distally, proximal tooth well-developed.

Sternum: Sternite 3 broad, 3.5 × as wide as long, anterolaterally produced, anterior margin minutely serrated, straight. Sternite 4 broadly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 2.2 × that of sternite 3, twice as wide as long.

Abdomen: Tergites 2–3 each with 2 elevated transverse ridges, tergite 4 with 1 transverse ridge, tergites 5–6 smooth; tergite 6 with transverse posteromedian margin.

Eye: Ocular peduncle slightly longer than wide; cornea subglobular, maximum corneal diameter 0.4 × rostrum width, cornea as broad as eyestalk.

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

Antenna: Article 1 with small distomesial spine not reaching end of article 2; article 2 with strong distomesial spine, longer than distolateral spine and 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 well-developed spine; extensor margin unarmed; crista dentata finely denticulate; merus having flexor margin with strong median spine and with or without minute distal spine, extensor margin with strong distal spine.

P1: 2.5 × carapace length, with numerous short striae, and uniramous setae scattered on merus to dactylus. Merus slightly shorter than carapace, 2.2 × as long as carpus, with strong mesial and distal spines, and scattered dorsal spines. Carpus 0.8 as long as palm, 1.8 × as long as broad, dorsal surface with scattered spines, mesial and lateral margins with 2 or 3 spines. Palm, 1.8 × as long as broad, armed with spines in irregular longitudinal rows on mesial and lateral margins, dorsal surface unarmed. Fingers 1.3 × as long as palm; fixed finger with row of spines along lateral margin; movable finger with proximal mesial spine.

P2–4: Slender, somewhat compressed laterally, with short setiferous striae on dorsal surface; ischium to dactylus sparsely with long and thick setae. Meri successively shorter posteriorly (P3 merus as long as P2 merus, P4 merus 0.9 × length of P3 merus). P2 merus 0.8 × carapace length, 5.1 × as long as broad, 1.1 × as long as P2 propodus; P3 merus 5.3 × as long as broad, 1.1 × as long as P3 propodus; P4 merus 7 × as long as broad, 1.2 × as long as P4 propodus; extensor margins with row of 8 or 9 proximally diminishing spines on P2–4; lateral surface unarmed; flexor margin with well-developed distal spine and several additional spines or projecting scales. Carpi with 2–4 well-developed spines on extensor margin on P2–4, lateral side smooth; flexor margin with small distal spine. Propodi 7.9–9.6 × as long as broad on P2–4, flexor margin with 3–5 movable spinules. Dactyli 0.4–0.5 × length of propodi; distal claw short, strongly curved; flexor margin nearly straight, with 7 or 8 small teeth decreasing in size proximally, each with slender movable spinule, ultimate tooth closer to distal claw than to penultimate tooth.

Colour in life. Unknown.

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

Distribution. New Caledonia, from 333 to 375 m.

Remarks. Leiogalathea turnus belongs to the group of the species having the hepatic margin of the carapace armed with one spine. This species is morphologically related to L. dido also from New Caledonia and adjacent waters, with a relatively small genetic divergence, 3.5% and 0.3% for COI and 16S, respectively. However, the two species are morphologically different, largely in the following particulars: in L. dido , the cornea is clearly narrower than the peduncle rather than being as equally wide, the P1 fingers are unarmed instead of bearing spines along their lateral and mesial margins, the P2–4 propodi are broader (the length-breadth ratio, 5.5–6.5 versus 7.6–9.6), the P4 merus is unarmed instead of bearing spines along extensor and flexor margins, and the rostrum is proportionally narrower (the length-breadth ratio, 1.1–1.2 versus 1.5).

Figures

FIGURE 11. Rostrum, and ocular peduncle, dorsal view. A, Leiogalathea evander n. sp., holotype, M 3.9 mm (MNHN-IU- 2015-820). B, L. imperialis (Miyake & Baba, 1967), holotype, ov. F 5.2 mm (BLIH 205a). C, L. juturna n. sp., holotype, F 4.2 mm (MNHN-IU-2013-17404). D, L. laevirostris (Balss, 1913), syntype, F 4.9 mm (ZMB17488). E, L. pallas n. sp., holotype, F 6.9 mm (MNHN-IU-2014-13395). F, L. paris n. sp., holotype, ov. F 4.0 mm (MNHN-IU-2011-4471). G, L. priam n. sp., holotype, M 5.0 mm (MNHN-IU-2014-13697). H, L. sinon n. sp., holotype, F 8.3 mm (MNHN-IU-2014-13711). I, L. turnus n. sp., holotype, M 8.0 mm (MNHN-IU-2014-13744). Scale = 1 mm.

FIGURE 20. Leiogalathea turnus n. sp., holotype, M 8.0 mm, New Caledonia (MNHN-IU-2014-13744). 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, 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. Scales: A, E, F, H, I = 1.0 mm; B–D, G = 0.5 mm.