Leiogalathea laevirostris ( Balss, 1913 ), 1990

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 : 237-239

Leiogalathea laevirostris ( Balss, 1913)

( Figs. 11D ; 15 )

Galathea laevirostris Balss, 1913: 221 .— Doflein & Balss 1913: 140, fig. 7, pl. 12, fig. 1.

Dubious identifications: Galathea laevirostris . — Laurie 1926: 135. Leiogalathea laevirostris . — Baba 2005: 88, 246.— Ahyong 2007: 14, fig. 8.— Rowden et al. 2010: tab. 3, 4.— Yaldwyn & Webber 2011: 213.

Type material. Lectotype: Sombrero Channel , Nicobar Islands. VALDIVIA Stn 211, 805 m, 8 February 1899: 1F 4.9 mm ( ZMB 17488).

Paralectotype: Sombrero Channel , Nicobar Islands. VALDIVIA Stn 211, 805 m, 8 February 1899: 1 M 4.8 ( ZMB 17488B) .

Description. Carapace: 1.3 × as long as broad. Mid-transverse ridge interrupted, followed by 5 interrupted transverse ridges. Lateral margins straight and subparallel, with 2 spines: first spine anterolateral well-developed; second small spine on anterior branchial margin; hepatic and posterior branchial margin unarmed. Rostrum 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 small teeth decreasing in size distally.

Sternum: Sternite 3 moderately broad, 3.0 × as wide as long, somewhat produced anterolaterally, anterior margin serrated, straight, with a median shallow notch. Sternite 4 narrowly contiguous to sternite 3; surface depressed in midline, smooth; greatest width 3.3 × that of sternite 3, 2.2 × as wide as long.

Abdomen: Tergite 2 with 2 elevated transverse ridges, tergites 3–4 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 0.7 × rostrum width, as wide as eyestalk.

Antennule: Article 1 with a spine on distomesial angle; lateral margin smooth.

Antenna: Article 1 with strong distomesial spine nearly reaching end of article 2; article 2 with subequal distolateral and distomesial spines, not 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: 2.7 (female, lost in male) × carapace length, with numerous short striae, and uniramous long setae scattered on merus to dactylus. Merus 0.9 length of carapace, 2.4 × as long as carpus, with strong mesial and distal spines, some scattered dorsal spines. Carpus slightly shorter than palm, 1.6 × as long as broad, dorsal surface with scattered spines, mesial margin with 3 strong spines, lateral margin unarmed. Palm, 1.9 × as long as broad, armed with spines in irregular longitudinal rows on mesial and lateral margins, dorsal surface unarmed. Fingers as long as palm; fixed finger with a row of spines along lateral border; movable finger with well-developed proximal mesial spine.

P3 (other pereiopods lost): Slender, somewhat compressed laterally, with short setiferous striae on dorsal surface, with sparse long and thick setae on ischium to dactylus. Merus, 0.7 × carapace length, 5 × as long as broad, 1.2 × as long as propodus; P3 merus 4.2 × as long as broad, 1.2 × as long as P3 propodus; extensor margins with a row of 7 proximally diminishing spines; flexor margin with 1 well-developed distal spine and several projecting scales. Carpi with 2 distal spines on extensor margin; flexor margin with small distal spine. Propodi 9 × as long as broad, flexor margin with 4 movable spinules. Dactyli 0.6 × length of propodi; distal claw short, moderately curved; flexor margin nearly straight, with 7 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 in life. Unknown.

Genetic data. No data.

Distribution. Andaman Sea, 805 m.

Remarks. Leiogalathea laevirostris belongs to the group of species having the hepatic margin of the carapace unarmed, the branchial margin with or without a spine, and the margin of the rostrum armed with 4 or 5 small teeth. The closest relatives are L. juturna from Indonesia and Taiwan, L. paris from Polynesia, Papua New-Guinea and New Caledonia, and L. priam from Papua New-Guinea. Leiogalathea laevirostris can be differentiated from these congeners by the more slender P2–4 propodi (9 versus 5–6 × as long as broad) and the distomesial margin of the antennule being armed with a small spine instead of being unarmed.

Unfortunately, we were not able to obtain molecular data for L. laevirostris .

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 15. Leiogalathea laevirostris (Balss, 1913), lectotype, F 4.9 mm (ZMB17488). 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, detached left pereiopod, probably P3, lateral view. G, dactylus of the same pereiopod, lateral view. Scales: A, E, F = 1.0 mm; B–D, G = 0.5 mm.