Leiogalathea priam, 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 : 245-247

Leiogalathea priam n. sp.

( Figs. 11G , 18 , 21F )

Type material. Holotype: Papua New Guinea. MADEEP Stn DW4287 , 09°12'S, 153°56'E, 340–375 m, 30 April 2014: M 5.0 mm (MNHN-IU-2014-13697).

Paratypes: Papua New Guinea. PAPUA NIUGINI DW3973 , 04°34'S, 146°17'E, 411–430 m, 5 December 2012 : 1 F 3.1 mm (MNHN-IU-2014-13793).—Stn DW3992 , 06°03’S, 147°36’E, 450–480 m, 9 December 2012 : 6 M 2.9–5.6 mm, 1 ov. F 3.6 mm, 2 F 3.9–4.2 mm (MNHN-IU- 2017-2391).

Papua New Guinea. MADEEP Stn DW4285 , 09°11'S, 153°55'E, 380–411 m, 30 April 2014: 1 M 5.2 mm (MNHN-IU-2015-212), 3 M 5.2–5.6 mm, 2 ov. F 4.8–5.2 mm, 2 F 3.4–3.8 mm (MNHN-IU-2014-9706), 1 ov. F 3.7 mm (MNHN-IU-2016-5797).—Stn DW4286 , 09°12'S, 153°55'E, 306–365 m, 30 April 2014: 4 M 4.6–5.1 mm, 2 ov. F 5.1–6.6 mm (MNHN-IU-2014-18341), 9 M 3.4–5.3 mm, 12 ov. F 3.0– 6.2 mm, 3 F 2.8–4.2 mm (MNHN- IU-2014-18573).—Stn DW4287 , 09°12'S, 153°56'E, 340–375 m, 30 April 2014: 13 M 3.4–7.2 mm, 18 ov. F 3.2– 6.1 mm, 1 F 4.3 mm (MNHN-IU-2014-9570), 1 M 4.5 mm, 1 ov. F 6.1 mm, 3 F 2.9–3.9 mm (MNHN-IU- 2017- 2396).—Stn DW4288 , 09°12'S, 153°54'E, 504 m, 30 April 2014: 1 F 5.1 mm (MNHN-IU-2016-522), 1 ov. F 4.8 mm (MNHN-IU-2014-13792).—Stn DW4314 , 09°48'S, 151°33'E, 278–420 m, 3 May 2014: 1 F 3.1 mm (MNHN- IU-2014-13696) .

Etymology. From the name Priam, the king of Troy in the Iliad. The name is considered a substantive in apposition.

Description. Carapace: 1.1–1.3 × as long as broad. Mid-transverse ridge uninterrupted or medially interrupted, followed by 5 interrupted or scale-like transverse ridges. Lateral margins straight and subparallel, with 2 small spines: first spine anterolateral; second small spine on anterior branchial margin (sometimes obsolescent), hepatic and posterior branchial margin unarmed. Rostrum moderately slender, horizontal, dorsally flattish or slightly concave, 1.5 × as long as broad, length 0.3 × and breadth 0.2–0.3 × that of carapace; lateral margin serrated with 4 or 5 minute teeth.

Sternum: Sternite 3 moderately broad, 2.0–2.5 × as wide as long, anterolaterally produced, anterior margin serrated, straight, with a minute median shallow notch. Sternite 4 narrowly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 3 × that of sternite 3, and 2.5 × as wide as long.

Abdomen: Tergites 2–3 each with 2 elevated transverse ridges, tergite 4 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 0.4 × rostrum width, as wide as eyestalk.

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

Antenna: Article 1 with strong distomesial spine nearly reaching end of article 2; article 2 with strong distomesial spine much larger than distolateral, 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 strong median spine, extensor margin with distal spine.

P1: 2.2 – 2.8 (males), 2.0 – 2.1 (females) × carapace length, densely covered with setiferous scales on merus to dactylus. Merus 0.7 length of carapace, 2.1 × as long as carpus, with strong mesial and distal spines, and scattered dorsal spines. Carpus slightly shorter than palm, 1.6 × as long as broad, dorsal surface with scattered spines, mesial margin with 2 spines (distal small), lateral margin with distal spine. Palm 2.1 × 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 usually unarmed or with several proximal spines along lateral margin; movable finger with welldeveloped proximal mesial spine.

P2–4: Stout, somewhat compressed laterally, with setiferous striae on dorsal surface, sparsely with long and thick setae on ischium to dactylus. Meri successively shorter posteriorly (P3 merus 0.9 × length of P2 merus, P4 merus 0.8 × length of P3 merus). P2 merus 0.6 × carapace length, 4.4 × as long as broad, 1.2 × as long as P2 propodus; P3 merus 4.2 × as long as broad, 1.2 × as long as P3 propodus; P4 merus 3.7 × as long as broad, as long as P4 propodus; extensor margins with row of 7 or 8 proximally diminishing spines on P2–3, unarmed on P4; lateral surface unarmed; flexor distal margin with well-developed distal spine and several additional projecting scales. Carpi with 2–4 spines on extensor margin on P2–3, unarmed on P4, lateral side smooth; flexor margin with small dorsal spine. Propodi 5.0–5.8 × as long as broad on P2–4, flexor margin with 4–6 movable spinules. Dactyli 0.6–0.7 × length of propodi; distal claw short, moderately curved; flexor margin nearly straight, with 6 or 7 small teeth along the entire margin decreasing in size proximally, each with slender movable spinule, ultimate tooth closer to penultimate tooth than to base of distal claw.

Colour in life. Ground colour reddish orange to pale yellow orange. Carapace and abdominal somites 2–3 orange, sparsely with whitish ridges, posterior part of abdomen translucent. P1 totally orange. P2–4 orange with whitish or pale orange bands, white to translucent at tips.

Distribution. Papua New Guinea, from 278 to 504 m.

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

Remarks. Leiogalathea priam belongs to the group of species having the hepatic margin of the carapace unarmed, the branchial margin armed with at most one spine, and the margin of the rostrum armed with 4 or 5 minute teeth. This species is morphologically very close to L. juturna from Indonesia and Taiwan and L. paris from French Polynesia, Papua New Guinea and New Caledonia. However, these species can be distinguished by the following differences:

The dorsal surface of the branchial regions has rows of setae not situated on marked discernible ridges in L. paris , whereas these setose ridges are clearly marked in L. juturna and L. priam .

In L. juturna and L. priam , a spine on the anterior branchial margin of the carapace is consistently present, whereas this spine is usually absent in L. paris .

The sternite 3 is 3.3–4.0 × as wide as long in L. juturna , whereas this sternite is 2.0–2.5 × in L. priam . .

The species are clearly divergent genetically: L. juturna and L. paris diverge on average 7.2% for COI and 1.4 % for the 16S. Leigalathea juturna and L. priam present higher genetic differences: 10.3% for COI and 4.0% for 16S. Leigalathea paris and L. priam are also highly divergent for COI (9%) and 16S (4.7 %).

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 18. Leiogalathea priam n. sp., holotype, M 5.0 mm, Papua New Guinea (MNHN-IU-2014-13697). 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, right P3, lateral view. I, right P4, lateral view. Scales: A, E, F, H, I = 1.0 mm; B–D, G = 0.5 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.