Galathea aequata, 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 : 31-34

Galathea aequata n. sp.

( Figs 6 , 115 D)

Dubious identifications:

Galathea affinis .— Nobili, 1907: 375, pl. 1, fig. 11 (Tuamotu Archipelago).— Peyrot-Clausade, 1989: 112 (Tuamotu Archipelago, 5–30 m).— Poupin, 1996: 19 (compilation of French Polynesia records).

Material examined. Holotype: French Polynesia. Society Islands. Moorea Island, 17.4964°S, 149.7528°W, 0–1 m, 20 June 2006: 1 M 4.1 mm (UF9860).

Paratypes: French Polynesia. Society Islands. Moorea Island, 17.5311°S, 149.9053°W, 0–2 m, 22 June 2005: 1 M 3.0 mm (UF10006), 1 M 3.3 mm, 1 ov. F 3.1 mm (UF10007).— N shore of Moorea, 3–5 m, 13 April 2006: 1 M 2.1 mm (UF9614).— NE corner of Moorea lagon, 0–2 m, 4 May 2006: 1 M 2.0 mm (UF9491).— Opunohu Bay, 3.5–4.5 m, 26 May 2006: 1 ov. F 3.0 mm (UF9424), 1 ov. F 3.3 mm (UF9620).— June–August 2006: 1 M 2.2 mm (UF13852). 17.4747°S, 149.8128°W, no depth: 2 ov. F 2.2–2.3 mm, 1 F 2.2 mm (UF10270), 1 M 2.9 mm (UF10280), 1 ov. F 2.7 mm (UF10281), 1 M 1.9 mm (UF10282).— 17.4775°S, 149.8412°W, 1–2 m, 18 October 2008: 1 M 4.1 mm (UF15761). Paorea Point, 0–0.5 m, 19 October 2008: 1 ov. F 2.7 mm (UF18369).— June 2009: 1 ov. F 3.0 mm (UF37852).— 17.4824°S, 149.824°W, 1 m, 1 November 2010: 1 M 2.2 mm (UF28828).

French Polynesia. Tuamotu Islands. 18 October 1965: 1 ov. F 3.2 mm (MNHN-IU-2013-9738).— 16 October 1965: 1 ov. F 3.4 mm (MNHN-IU-2013-9739).— Mururoa Atoll, ref. 248, 1965: 1 M 3.5 mm (MNHN-IU-2013- 9737).— April 1996: 3 M 3.6–4.0 mm, 2 ov. F 3.6–4.1 mm (MNHN-IU-2013-14170).— Makemo Atoll, April 2009: 1 M 3.6 mm (UF18685).— Hao Atoll, 18.0709°S, 140.9822°W, 0.5–2 m, 17 January 2013: 1 ov. F 2.1 mm (UF35295).

French Polynesia. Gambier Islands. Terevai Island, 23.144°S, 135.0968°W, 13.7 m, 30 January 2013: 1 M 3.9 mm (UF35419).— 23.1548°S, 135.0189°W, 23.2 m, 2 February 2013, 1 M 1.3 mm.— 23.1517°S, 135.0554°W, 0.5–9 m, 8 February 2013: 1 M 2.0 mm (UF35498).

Etymology. From the Latin aequatus, equality, in reference to the similiraty with G. mauritiana .

Description. Carapace: As long as broad; anterior cervical groove indistinct; transverse ridges with dense short setae, and a few scattered long and thick setae. Gastric region with some transverse ridges: 1 epigastric ridge with 2 submedian spines, medially interrupted; protogastric ridge uninterrupted and extending laterally to first anterolateral spine, laterally interrupted in some specimens; 1 mesogastric ridge uninterrupted and extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, anterior ridge convex and usually uninterrupted, not extending laterally to anterior branchial ridges, posterior ridge short, sometimes absent. Midtransverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges, 2 of them uninterrupted. Lateral margins medially convex, with 8 spines: 2 spines in front of and 6 spines behind indistinct anterior cervical groove; first anterolateral, well-developed, behind level of external limit of orbit; second minute, 1 spine ventral to between first and second; 3 spines on anterior branchial margin, and 3 spines on posterior branchial margin, last small. External limit of orbit unarmed, with well-developed frontal spine between external limit of orbit and anterolateral spine, infra-orbital margin with strong spine. Rostrum broadly triangular, 1.3–1.4 times as long as broad, length 0.5 of, breadth 0.3–0.4 of carapace, distance between distalmost lateral incisions 0.3 distance between proximalmost lateral incisions, dorsal surface slightly concave medially; lateral margin with 4 sharp teeth.

Pterygostomian flap rugose, with 1 distinct spine on upper margin near linea anomurica, anterior margin ending in well-developed spine.

Sternum: Slightly longer than broad, lateral limits divergent posteriorly.

Abdomen: Somites 2–4 each with 2 uninterrupted transverse ridges on tergite; somites 5 and 6 each with 2 ridges, medially interrupted, posteromedian margin of somite 6 distinct. Males with G1 and G2.

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with 3 well-developed distal spines, distodorsal larger; distomesial smaller than others. Ultimate article with a few short setae not in tuft on distodorsal margin.

Antenna: Article 1 with depressed distomesial process not reaching distal margin of article 2. Article 2 with subequal distal spines, reaching midlength of article 3. Article 3 with distinct distomesial spine. Article 4 unarmed.

Mxp3: Ischium with well-developed distal spine on flexor margin; extensor margin unarmed; crista dentata with 22–24 denticles. Merus shorter than ischium, with strong proximal spine on flexor margin, located at midlength, and clearly not reaching distal margin of merus, small or obsolescent distal spine on flexor margin; extensor margin with distal spine. Carpus spineless.

P1: 1.8–2.5 times carapace length, relatively slender, subcylindrical, with numerous short setae and some long setae on dorsal surface and along lateral and mesial margins of all articles. Merus 0.8–0.9 length of carapace, 1.3–1.5 times as long as carpus, with rows of spines, mesial and distal spines strong. Carpus as long as palm, 1.7–2.1 times longer than broad, lateral and mesial margins subparallel, dorsal surface with small spines; mesial surface with row of 3 or 4 well-developed spines; and row of small spines along lateral margin. Palm 1.4–1.7 times longer than broad; spines arranged in irregular longitudinal rows on dorsal, mesial and lateral surfaces, lateral row continued onto whole lateral margin of fixed finger. Fingers as long as palm, each finger distally with two rows of teeth, spooned; movable finger with row of dorsomesial spines.

P2–4: Relatively slender, somewhat compressed, moderately setose, sparsely with long setae on all articles. P2 1.5 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 0.6 carapace length, 2.9–3.0 times as long as broad, 1.4 times longer than P2 propodus; P3 merus 3.0 times as long as broad, 1.2 times length of P3 propodus; P4 merus 2.4 times as long as broad, 1.0–1.2 length of P4 propodus; extensor margins each with row of 8–10 proximally diminishing spines in P2–3, 1 or 2 distal spines in P4; lateral surfaces unarmed in P2–3, 1 or 2 spines in P4; 2 well-developed spines on terminal flexor margins, sometimes obsolescent in P4; flexor mesial margin with terminal spine on P2 only. Carpi each with 3 or 4 spines on extensor margin in P2–3, 0 or 1 minute spine in P4; lateral surfaces with row of 2 or 3 acute granules or spines paralleling extensor row in P2–3, obsolescent in P4; flexor distal margins ending in acute projection. Propodi 3.4–3.6 times as long as broad in P2–4; extensor margins each with 3 proximal spines in P2, unarmed in P3–4; flexor margins each with 5 or 6 (rarely 4) slender movable spines in P2–4; lateral surfaces unarmed. Dactyli 0.6–0.7 length of propodi, ending in incurved, strong, sharp spine; flexor margins each with prominent triangular terminal tooth preceded by low 4 teeth, each tooth bearing robust setae.

Epipods absent on pereiopods.

Coloration. Ground color of carapace, abdominal somites 2–4 and pereopods greenish, with darker transverse ridges; some whitish patches scattered on carapace and abdomen surface. Distal part of P1 palm and proximal portion of P1 fingers whitish; one distinct black spot and one yellow spot on distal part of P1 palm.

Remarks. The new species resembles G. mauritiana Bouvier, 1914 and G. a c i s n. sp. (for details, see Remarks for these species). Previous records of G. affinis from French Polynesia, are likely to be G. aequata , andshould be confirmed after the examination of the specimens.

Distribution. French Polynesia, Society, Gambier and Tuamotu Islands, 0– 23 m.

Figures

FIGURE 6. Galathea aequata n. sp., holotype, male, 4.1 mm, French Polynesia (UF 9860). 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, left P 2, lateral view; G, right P 4, lateral view. Scale: A, E – G = 1 mm; B – D = 0.5 mm.

FIGURE 115. Dorsal view. A, Galathea acis n. sp., Vanuatu, male 3.7 mm (MNHN-IU- 2013 - 15899). B, Galathea aegyptiaca Paul’son, 1875, Red Sea, female 4.2 mm (UF 37107). C, Galathea aegyptiaca Paul’son, 1875, Madagascar, male 3.4 mm (MNHN-IU- 2010 - 2739). D, Galathea aequata n. sp., French Polynesia, male 4.1 mm (UF 15761). E, Galathea ahyongi n. sp., Red Sea, Saudi Arabia, ovigerous female 3.5 mm (UF 36149). F, Galathea amamiensis Miyake & Baba, 1966, Vanuatu, female 2.9 mm (MNHN-IU- 2013 - 8182). G, Galathea amamiensis Miyake & Baba, 1966, Papua New Guinea, female 3.1 mm (MNHN-IU- 2013 - 356). H, Galathea autahi n. sp., French Polynesia, male 4.8 mm (MNHN-IU- 2013 - 13569). I, Galathea bimaculata Miyake & Baba, 1966, Papua New Guinea, ovigerous female 2.5 mm (MNHN-IU- 2013 - 13907).