Lauriea gardineri ( Laurie, 1926 )

Macpherson, Enrique & Robainas-Barcia, Aymee, 2013, A new genus and some new species of the genus Lauriea Baba, 1971 (Crustacea, Decapoda, Galatheidae) from the Pacific and Indian Oceans, using molecular and morphological characters, Zootaxa 3599 (2), pp. 136-160 : 144-146

Lauriea gardineri ( Laurie, 1926)

( Figs 3 , 8 A, 9A)

Galathea gardineri Laurie, 1926: 131 , pl. 9, figs 1–5 (Providence, 106 m).—Baba, 1990: 961 ( Madagascar, 50 m). Dubious records:

Galathea gardineri Tirmizi, 1966: 177 , fig. 2 (Red Sea, 29–55 m).— Lewinsohn, 1969: 112 (no record). Lauriea gardineri Lewinsohn, 1982: 299 , fig. 1 (Gulf of Aqaba (northern Red Sea), 3–81 m).— Tirmizi & Javed, 1993: 23, figs

10–11 (western Indian Ocean off Somali Republic, Andaman Islands, 66–177 m).— Baba, 1994b: 43, fig. 2 ( Madagascar,

New Caledonia).

Material examined. Neotype: Madagascar. ATIMOVATAE. Stn CP3624, 25°38.1'S, 45°57.0'E, 63 m, 15 May 2010: 1 M 2.8 mm (MNHN-IU-2010-5254).

Madagascar. ATIMOVATAE. Stn TB02, 25°01.3'S, 47° 00.5'E, 18 m, rock, 1 May 2010: 1 M 1.8 mm (MNHN- IU-2010-5252).—Stn DW3563, 25°37'S, 46°18'E, 347–355 m, 6 May 2010: 1 M 2.6 mm (MNHN-IU-2010- 5256).—Stn CP3579, 25°54.5'S, 45°33.2'E, 65–66 m, 9 May 2010: 1 ov. F 2.6 mm (MNHN-IU-2010-5255).—Stn DW3605, 24°54.5'S, 44°51.0'E, 56–57 m, 13 May 2010: 1 M 2.4 m (MNHN-IU-2010-5257).—Stn CP3624, 25°38.1'S, 45°57.0'E, 63 m, 15 May 2010: 1 M 2.8 mm, 1 F 2.7 mm (MNHN-IU-2010-5253).

Madagascar. MIRIKY. Stn DW3246, 14°52'S, 46°58'E, 235–241 m, 7 July 2010: 1 M 2.4 mm (MNHN-IU- 2010-1018).

Description. Carapace: as long as wide, dorsal surface covered with long and short setae both arising from numerous short transverse and more or less elevated ridges; small spines scattered on dorsal surface, 2 largest spines on epigastric region; transverse ridge anterior to posterior margin usually unarmed. Cervical groove indistinct. Lateral margins convex, with 7 small but distinct spines on each side, last spine sometimes mesial to lateral margin; first (anterolateral) small, lateral to lateral limit of orbit, remainder more or less distantly separated from one another; 1 small spine mesial to anterolateral spine. Rostrum sharply triangular, with 4 moderately incised teeth, dorsal surface slightly concave, with a few long setae; length (measured from the tip to level of orbital margin) 0.5 times carapace length, and subequal to width (measured at level of orbital margin); rostral spine and distalmost lateral tooth with straight lateral margins.

Abdomen: somites with thick long coarse uniramous setae. Somites 2–4 each with 2 transverse setiferous ridges each preceded by groove.

Sternum: sternite 3 with anterior margin produced, 2.8 times wider than long; sternite 4 nearly twice as wide as sternite 3, and 3.9 times wider than long.

Eyes: orbit not laterally produced, unarmed. Eyestalks moderately elongate, 1.6 times longer than wide, reaching end of antennal peduncle, proximally somewhat wider, distally with long setae directly proximal to cornea; cornea not swollen, length slightly less than that half of remaining eyestalk.

Antennule: article 1 with 3 distal spines: distomesial slender, distolateral well developed, dorsolateral larger than distolateral; 2 slender terminal segments, ultimate segment with tuft of pronounced setae on extensor distal margin.

Antenna: article 1 with ventromesial process ending in short acute spine not reaching end of article 2, article 2 with distomesial spine exceeding article 4, distolateral spine reaching end of article 3, additional spine on mesial margin; article 3 unarmed or with small distomesial spine.

Mxp3: ischium slightly longer than merus when measured in lateral midline, flexor margin with short distal spine, mesial ridge with 23 or 24 denticles. Merus with 2 subequal spines on flexor margin. Carpus with small distal spine on flexor margin.

P1: 3.2 times carapace length; very setose dorsally, scarcely setose or nearly glabrous ventrally; plumose and non-plumose long setae, partly coarse, arising from numerous short striae. Merus as long as carapace, with spines along lateral, dorsal and mesial sides, mesial spines larger, distal ones prominent. Carpus 1.5 times longer than wide, equally wide as propodus, and 0.6 length of merus; some scattered small spines on dorsal side, row of strong spines along mesial margin, some small spines on ventral side. Palm 2.1 times as long as wide; dorsal surface unarmed, with some long setae arising from a few short striae, mesial margin with row of several spines, lateral margin with row of spines continued on to fixed finger. Fingers shorter or as long as palm, not gaping, tips crossing when closed; terminating in sharp curved spine; dorsal surface unarmed. Movable finger unarmed on mesial margin.

P2–4: P2 1.6–1.8 times carapace length, very setose on margins, with long plumose and non-plumose setae. P2–4 meri posteriorly diminishing in size, extensor margin more or less rounded, with row of proximally diminishing spines; row of well-developed spines on flexor margin, 0–2 small spines on lateral side, and 2 extra spines on terminal margin close to distal flexor marginal spine, lateral side with long setae arising from numerous short striae; P2 merus 0.9 times carapace length, 3.7 times longer than wide, and 1.7 times longer than propodus. Carpi with small spines (3 or 4 on P2, 0–2 on P3–4) on extensor margin (distal one usually larger). Propodi with small spines along extensor proximal margin and 5 or 6 movable slender spines on flexor margin, terminal paired; P2 propodus ca. 3.6 times longer than wide, and more than 1.8 times dactylus length. Dactyli sharply biunguiculate, terminal claw strongest.

Colour. Ground colour of carapace and abdomen whitish, with numerous minute brown spots, setae brownish. P1 with large brown and whitish bands, a red spot on dorsal side of merus. P2–4 whitish, with numerous minute brown spots, setae whitish.

Remarks. Lauriea gardineri was described from two males and one ovigerous female collected in the western Indian Ocean (Providence and Seychelles Islands) ( Laurie 1926). Unfortunately the types of the species are lost. We consider L. gardineri to be the most common species in northern and southern Madagascar, although additional topotypic samples from the type localities would be desirable in order to select a neotype. Therefore, a specimen from Madagascar is selected here to fix the identity of the species. The existence of numerous species of Lauriea , only distinguished by subtle morphological differences, molecular and colour data does not allow accurate confident identification at this stage. It seems that L. gardineri is restricted to the western Indian Ocean. However, the existence of a second species in the area ( Lauriea adusta ), that is also found in the western Pacific, suggests caution in this geographical restriction. In any case, additional studies of the material collected in the western Indian Ocean, from the Red Sea ( Tirmizi 1966; Lewinsohn 1969, 1982) and Somali Republic ( Tirmizi & Javed 1993) to Madagascar (Baba 1990, 1994) are recommended.

Lauriea gardineri is closely related to L. simulata from the western Pacific Ocean, in having the rostrum slightly concave on the distal portion, both the rostral spine and the distalmost lateral teeth with straight lateral margins, and the distomesial spine of the antennal article 2 clearly exceeding the article 3.

However, these species are distinguished by the following differences:

- The eye reaches the end of the antennal peduncle in L. gardineri , instead of exceeding the antennal peduncle as in Lauriea simulata .

- In L. gardineri , the ground colour of the carapace and abdomen is whitish, with numerous minute brown spots, P1 has large brown and whitish bands, and a red spot on the dorsal side of merus. In L. simulata , the ground colour is whitish, with some yellow spots circled by brown on the carapace and abdomen, P1 is whitish and brownish marbled, with some yellow spots circled by brown on merus and carpus.

The genetic divergences between L. gardineri and Lauriea simulata were 5.2% (COI) and 0.7% (16S rRNA). Lauriea adusta , the second species from Madagascar, can be distinguished from L. gardineri by the following differences:

- The rostrum is dorsally flattish instead of slightly concave on the distal portion, and the rostral spine and the distalmost lateral teeth have convex instead of straight lateral margins.

- The distomesial spine of the antennal article 2 reaches the end of the article 3 rather than exceeding the antennal peduncle.

- The ground colour of the carapace and abdomen is brownish or whitish, without coloured spots, and the P1 is brownish or whitish, without coloured bands, in Lauriea adusta , whereas the ground colour of the carapace and abdomen is whitish, with numerous minute brown spots, the P1 has large brown and whitish bands, and a red spot on the dorsal side of merus in L. gardineri .

The genetic divergences between L. gardineri and Lauriea adusta were 10.6% (COI) and 3.2% (16S rRNA).

Distribution. Western Indian Ocean ( Madagascar, Providence and Seychelles Islands), between 18 and 241 m.

Figures

FIGURE 3. Lauriea gardineri Laurie, 1926, neotype, male, 2.8 mm, Madagascar, ATIMOVATAE, Stn CP 3624 (MNHN-IU- 2010 - 5254). A, carapace and abdomen, dorsal view; B, sternal plastron, sternites 3 and 4; C, left cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp 3, lateral view; E, right P 1, dorsal view; F, left P 2, lateral view, broken; G, left P 4, lateral view. H, Madagascar, male, 2.4 mm, ATIMOVATAE, Stn CP 3605 (MNHN-IU- 2010 - 5257), right P 3, lateral view. Scale: A, E – H = 1 mm; B – D = 0.5 mm.

FIGURE 8. Rostrum and anterior portion of carapace, dorsal view. A, Lauriea gardineri Laurie, 1926, ovigerous female, 2.4 mm, Madagascar, ATIMOVATAE, Stn DW 3605, male, 2.4 mm. B, Lauriea simulata, New Caledonia, LIFOU, Stn 1448, male, 1.8 mm. C, Lauriea punctata, Vanuatu, SANTO, Stn AT 85, male, 2.6 mm. D, Lauriea adusta, Philippines, PANGLAO, Stn B 39, male, 2.0 mm. E, Lauriea teresae, French Polynesia, Moorea Island, male, 1.8 mm. F, Triodonthea setosa, New Caledonia, SMIB 5, Stn DW 100, ovigerous female, 4.8 mm. Scale, 0.5 mm.