Leiogalathea imperialis ( Miyake & Baba, 1967 )

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 : 233-235

Leiogalathea imperialis ( Miyake & Baba, 1967)

( Figs. 11B , 13 )

Galathea imperialis Miyake & Baba, 1967: 213 , figs 1, 2.

Leiogalathea imperialis .— Baba 1969: 3.

Type material. Holotype: WSW of Joga-shima Islet , Sagami Bay, 160–230 m, 19 March 1958: ov. F 5.2 mm ( BLIH 205 a).

Paratype: Collected with holotype: ov. F 4.2 mm ( BLIH 205 b) .

Description. Carapace: 1.3 × as long as broad. Mid-transverse ridge interrupted, preceded by shallow cervical groove, followed by 8–11 interrupted or scale-like transverse ridges. Lateral margins slightly convex, with 2 or 3 spines: first spine anterolateral, well-developed; hepatic margin unarmed; small spine on anterior branchial margin, with or without small spine on posterior branchial margin. Rostrum horizontal, dorsally flattish and slightly directed downwards, 1.5 × as long as broad, length 0.4 × and breadth 0.3 × that of carapace; lateral margin unarmed, smooth.

Sternum: Sternite 3 acutely broad, 3.9 × as wide as long, anterolaterally produced, anterior margin smooth, straight, with a median minute shallow notch. Sternite 4 narrowly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 3.6 × that of sternite 3, 2.6 × as wide as long.

Abdomen: Tergite 2 with 2 elevated transverse ridges, tergite 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 0.7 × rostrum width, as wide as eyestalk.

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

Antenna: Article 1 with distomesial spine nearly 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 small spine; extensor margin unarmed; crista dentata finely denticulate; merus having flexor margin with strong median spine, extensor margin with distal spine.

P1: 2.4 × carapace length, with scattered short striae, and densely covered by uniramous long setae on merus to dactylus. Merus 0.8 length of carapace, twice as long as carpus, with strong mesial and distal spines, and scattered dorsal spines. Carpus 0.8 × shorter than palm, 1.8 × as long as broad, dorsal surface with sparse spines, mesial and lateral margins with several spines. Palm 1.7 × as long as broad, armed with spines in irregular longitudinal rows on mesial and lateral margins, dorsal surface unarmed. Fingers 1.4 × as long as palm; fixed finger with 2 welldeveloped lateral proximal spines; movable finger with 1 well-developed proximal spine on mesial margin.

P2–4: slender, somewhat compressed laterally, with short setiferous striae on dorsal surface; with sparse long and 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 as long as carapace, 6.9 × as long as broad, 1.1 × as long as P2 propodus; P4 merus 4.7 × as long as broad, 1.1 × as long as P4 propodus; extensor margins with a row of 6 or 7 proximally diminishing spines on P2–3; 2 distal spines on P4; lateral surface unarmed; flexor margin with 1 welldeveloped distal spine and several additional projecting scales. Carpi with 1–3 spines on extensor margin on P2–3, unarmed on P4, lateral side smooth; flexor margin with small distal spine. Propodi 7.5–8.5 × as long as broad on P2–4, flexor margin with 3–5 movable spinules. Dactyli 0.6 × length of propodi; distal claw short, moderately curved; flexor margin nearly straight, with 5 or 6 small teeth decreasing in size proximally, each with slender movable spinule, ultimate tooth equidistant between base of distal claw and penultimate tooth.

Colour in life. Unknown.

Genetic data. No data.

Distribution. Japan, Sagami Bay, between 160 and 230 m.

Remarks. Leiogalathea imperialis belongs to the group of species having the hepatic margin of the carapace unarmed and the margin of the rostrum smooth. Leiogalathea imperialis morphologically resembles L. amata from Wallis and Futuna and New Caledonia. However, they can be differentiated by the presence or absence of 1 small spine on the posterior branchial margin of the carapace (present in L. imperialis , absent in L. amata ).

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 13. Leiogalathea imperialis (Miyake & Baba, 1967), holotype, ov. F 5.2 mm, Sagami Bay, Japan (BLIH 205a). A, carapace and abdomen, dorsal view. B, sternites 3–4. C, cephalic region, showing antennular and antennal peduncles, ventral view. D, left Mxp3 ischium and merus, ateral view. E, right P1, dorsal view. F, right P2, lateral view. G, dactylus of left 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.