Galathea villosa, Macpherson, Enrique & Robainas-Barcia, Aymee, 2015

Macpherson, Enrique & Robainas-Barcia, Aymee, 2015, Species of the genus Galathea Fabricius, 1793 (Crustacea, Decapoda, Galatheidae) from the Indian and Pacific Oceans, with descriptions of 92 new species, Zootaxa 3913 (1), pp. 1-335 : 315-317

Galathea villosa n. sp.

( Fig. 112 )

Material examined. Holotype: Mozambique. MAINBAZA, Stn CP3133, 25°10.07’S, 35° 10.56E, 200–201 m, 10 Abril 2009: M 3.3 mm (MNHN-IU-2008-10226).

Paratypes: Mozambique. MAINBAZA, Stn CC3150, 19°30.58’S, 36°46.72’E, 261–264 m, 13 April 2009: 1 F 2.9 mm (MNHN-IU-2013-9758).—Stn CC3160, 23°57'70"S, 35°39'59"E, 206–210 m, 15 April 2009: 1 ov. F 5.6 mm (MNHN-IU-2013-13976).—Stn CC3175, 25°32.70¨S, 33°12.09¨E, 155–165 m, 17 April 2009: 1 M 2.5 mm, 3 ov. F 3.0– 3.4 mm (MNHN-IU-2013-13975); 1 ov. F 3.2 mm (MNHN-IU-2008-10228).

Madagascar. Stn CH 45, 16°20.5’S, 46°09’E, 310-350 m, 7 November 1972: 1 F 2.6 mm (MNHN- Ga704).—Stn CH 44, 15°25.7’S, 46°01’E, 200–210 m, 7 November 1972: 2 M 3.4–4.8 mm, 1 F 3.5 mm (MNHN- Ga719).—Stn 52, 15°21'S, 46°12.5'E, 150 m, 8 November 1972: 1 M 4.7 mm (MNHN-Ga718, MNHN-IU-2013- 9697).— 13°22'S, 47°38'E, 0–200 m, 4 December 1974: 1 M 5.6 mm (MNHN-Ga1485, MNHN-IU-2013- 14275). MIRIKI, Stn CP3188, 12°31'S, 48°22'E, 298–301 m, 27 June 2009: 1 F 6.3 mm (MNHN-IU-2010- 1115).—Stn CP3261, 15°35'S, 45°43'E, 197–217 m, 10 July 2009: 1 ov. F 4.3 mm (MNHN-IU-2010-1323).—Stn CP3282, 14°52'S, 46°58'E, 215–261 m, 13 July 2009: 1 M 4.1 mm (MNHN-IU-2010-1015).

Vanuatu. MUSORSTOM 8, Stn CP1087, 15°10.18’S, 167°14.07’E, 394–421 m, 6 October 1994: 1 ov. F 5.0 mm (MNHN-IU-2013-15935).

Etymology. From the Latin villosus, hairy, in reference to the numerous setae on the body.

Description. Carapace: As long as broad; transverse ridges with dense moderately long setae; some additional long and thick iridescent setae scattered on each region; cervical groove distinct, laterally bifurcated; most ridges on gastric region interrupted, with some scattered scale-like ridges; epigastric region with 10–15 spines; 2–6 small hepatic spines on each side; 1–4 small parahepatic spines on each side lateral to anterior protogastric ridge; some additional small spines on protogastric, anterobranchial and laterobranchial regions in some specimens; anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 6 ridges. Lateral margins slightly convex medially, with 7–12 spines: 2 spines in front of and 5–10 spines behind anterior cervical groove; first anterolateral, well-developed, at level of orbit, second very small but distinct, located at midlength between first spine and anterior cervical groove, with small spine ventral to between first and second; 2–5 spines on anterior branchial margin, and 3–5 spines on posterior branchial margin. Small outer orbital spine; infraorbital margin with strong spine. Rostrum lanceolate, 1.9–2.0 times as long as broad, length 0.6 that of, breadth 0.3 that of carapace; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with some unirramous setae; lateral margin with 4 moderately incised sharp teeth.

Pterygostomian flap rugose, with sparse short setae, anterior margin bluntly angular.

Sternum: About as long as broad; lateral extremities gently divergent posteriorly.

Abdomen: Somites 2–4 each with 3–4 uninterrupted transverse ridges on tergite, anterior ridge slightly more elevated than posterior ridge; somites 5 and 6 each with 2 medially interrupted ridges. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.6 rostrum width.

Antennule: Article 1 with 2 well-developed distodorsal and distolateral spines, distodorsal larger; distomesial spine obsolescent; 1–3 small spines on lateral margin. Ultimate article with a few long fine setae not in tuft on distodorsal margin.

Antenna: Article 1 with distomesial spine barely reaching or exceeding distal margin of article 2. Article 2 with 2 well-developed distal spines, distolateral spine longer than distomesial and reaching end of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with well-developed spine on flexor distal margin; crista dentata with 20 or 21 denticles. Merus shorter than ischium; flexor margin with 3 spines, proximal stronger than others; extensor margin with 1 or 2 welldeveloped distal spine. Carpus unarmed.

P1: 3.2–3.5 times carapace length, with numerous finely setiferous scales, with long thick iridescent setae. Merus 1.4 times length of carapace, 1.9–2.0 times as long as carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus 0.7 length of palm, 2.4–2.7 times as long as broad; dorsal surface with small spines arranged roughly in longitudinal rows; mesial row of well-developed spines. Palm 2.5–3.2 times longer than broad, lateral and mesial margins with small spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side. Fingers 0.7–0.8 length of palm, each finger distally with two rows of teeth, spooned; mesial margin of movable finger and lateral margin of fixed finger unarmed.

P2–4: Moderately long and slender, with setose striae and some long iridescent setae. P2 2.0–2.2 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.7–0.9 carapace length, 6.0 times as long as broad, 1.2–1.4 times longer than P2 propodus; P3 merus 4.0 times longer than broad, 1.1 times longer than P3 propodus; P4 merus 2.8–3.1 times as long as broad, 1.1 length of P4 propodus. Extensor margins of meri with row of 8–10 proximally diminishing spines on P2–3, 5 spines on P4; flexor margins distally ending in strong spine followed proximally by 1–4 small spines and several tubercles or eminences; lateral sides with some minute spines on P2–4. Carpi with 5–7 spines on extensor margin, distalmost longer than distal second; lateral surface with 3–5 small spines and acute granules sub-paralleling extensor margin on P2–4; flexor distal margin with small spine. Propodi 5.2–6.0 times as long as broad; extensor margin with 4–7 small proximal spines on P2–4; some proximal spines on lateral side of P2–4; flexor margin with 5–7 slender movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.4–0.6 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods on P1.

Remarks. The present specimens referred to Galathea villosa n. sp. exhibit notable variation in some morphological characters. For instance, the walking legs are more slender in the ovigerous female from Vanuatu than in those from Madagascar. The genetic divergences between the specimens from these two localties are not very large (<5%). Therefore we have considered these morphological differences as intraespecific variability until the collection of additional material from Vanuatu confirms its taxonomic status.

Galathea villosa n. sp. belongs to the group of species which is characterized by the presence of more thanfour or more epigastric spines and often spinules on hepatic and branchial regions on the carapace, the lateral margin of the carapace bearing one small but distinct spine between the anterolateral spine and the anteriormost spine of the branchial margin, and the antennular basal article having only two well-developed terminal spines (the distomesial spine minute or obsolescent). Galathea villosa is very close to G. crinita n. sp. from New Caledonia and Chesterfield Islands but the two can be easily distinguished by the following characters:

- The dorsal surface of the carapace has numerous long thick iridescent setae in G. v i l l o s a, whereas these long setae are very scarce in G. crinita .

- The P2 merus is 5–6 times as long as broad in G. villosa , being 3–4 times in G. crinita . - The genetic divergence between both species is 16.2% (COI) ( Tab. 2 ).

Distribution. Madagascar, Mozambique, and Vanuatu, 150– 421 m.

Figures

FIGURE 112. Galathea villosa n. sp., holotype, male, 3.3 mm, Mozambique (MNHN-IU- 2008 - 10226). A, carapace and abdomen, dorsal view; B, thoracic sternites 3 and 4; C left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap; D, ischium, merus and carpus of right Mxp 3, lateral view; E, right P 1, dorsal view; F, right P 2, lateral view; G, left P 3, lateral view; H, left P 4, lateral view. Scale: A, E – H = 1 mm; B – D = 0.5 mm.