Galathea acis, 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 : 22-26

Galathea acis n. sp.

( Figs 3 , 115 A)

Galathea affinis . — Baba, 1979b: 646 (Gorong Island, subtidal).

Possible references:

Galathea affinis Ortmann, 1892: 252 , pl. 11, figs 9a, i ( Fiji Islands).— Borradaile, 1898: 463 (Rotuma, Funatufa).— Borradaile, 1900: 421 (Lifu, Loyalty Islands).— De Man, 1902: 711 ( Ternate).— Miyake & Baba, 1966: 57, figs 1, 2 (Ishigaki-jima, Okinawa-jima, Amami-oshima, intertidal).— Baba, 1977a: 247 (Timor, Biak I. and Hollandia, New Guinea).— Baba, 1982b: 59 ( Palau Islands and Yap Island, subtidal).— Kawamoto & Okuno, 2003: 94, unnumbered fig. (Kume-jima, Okinawa, 10 m).— Dong & Li, 2010: 13, fig. 8 (South China Sea, intertidal to 50 m).

? Galathea affinis .— Gordon, 1935: 4, figs 1, 3c (Banda Neira [=Banda Naira]).

Material examined. Holotype: Vanuatu. SANTO, Stn DB1, 15°33.1'S, 167°17.8'E, 15–25 m, 10 September 2006: 1 M 3.7 mm (MNHN-IU-2013-15899).

Paratypes: Japan. Ryukyu Islands. Iriomote Island, Uehara, 24.4212°N, 123.8026°E, 0–1 m, 10 July 2010: 1 ov. F 3.1 mm (UF26919), 1 M 3.0 mm (UF26920).—Okinawa Island, Miyagi Beach, Sunabe, Chatan, 26.3288°N, 127.7441°E, 3–10 m, 20 July 2010: 1 M 3.0 mm (UF35244).—Okinawa Island, Inanse, Urasoe, 26.2517°N, 127.6722°E, 0–1 m, 15 May 2011: 1 M 3.1 mm (UF28654), 1 ov. F 2.2 mm (UF28661), 1 M 4.1 mm (UF28662).

Mariana Islands. Guam Island, Haputo, 13.577°N, 144.826°E, 6–30 m, 16 June 2010: 1 ov. F 3.3 mm (UF26599). Saipan Island, 15.2°N, 145.7°E, 1 M 4.3 mm (UF37899).—Apra harbour, Sasa Bay, 3.5–5 m, 9 July 1997: 1 juv. 1.2 mm (UF316).— Double reef, 5 m, 7 May 1999: 1 M 4.1 mm (UF469).—Pago Bay, 4–8 m, 14 August 2000: 1 M 4.3 mm (UF393).—Double reef, 8 May 2002: 1 ov. F 3.7 mm (UF5659).—Asan Point, 0.5–1.5 m, 3 July 2002: 1 F 2.9 mm (UF2833).—Gun beach, 13.5167°N, 144.8°E, 5–15 m, 18 June 2003: 1 M 4.1 mm (UF4111).—Tumon Bay, 1–2 m, June–July 2003: 1 M 3.5 mm (UF4043).—Piti, 0–2 m, 13.4267°N, 144.7961°E, 18 March 2008: 1 F 2.0 mm (UF13377), 1 M 2.8 mm (UF13830).—Tanguisson, 7–25 m: 1 M 3.2 mm (UF7394).

Indonesia. Gorong Island. 27 January 1975: 1 M 1.8 mm (MNHN-Ga1142).

Samoa, American Samoa, Ofu Island. National Park, February–April 2007: 1 ov. F 3.1 mm (UF9541), 1 F 1.9 mm (UF14725).

Papua New Guinea. PAPUA NIUGINI, Stn PM25, 05°01.1'S, 145°47.9'E, 0 m, 15 November 2012: 1 ov. F 3.6 mm (MNHN-IU-2013-655).—Stn PD36, 05°01.2'S, 145°47.9'E, 5–10 m, 19 November 2012: 1 M 2.0 mm (MNHN-IU-2013-15931).

Australia. Queensland. Lizard Island, Young reef, 15–18 m, 18 February 2009: 1 ov. F 3.5 mm (UF17132).—Lizard Island, Day Reef, 2–3 m, 22 February 2009: 1 ov. F 3.5 mm (UF17848).— 14.7452°S, 145.5066°E, 1–2 m, 24 February 2009: 1 ov. F 3.0 mm (UF17464).

Australia. Christmas Islands, near indian Ocean lodge, 2 December 1999: 1 ov. F 3.1 mm (UF5642).

Vanuatu. SANTO, Stn DB1, 15°33.1'S, 167°17.8'E, 15–25 m, 10 September 2006: 5 M 1.8–3.6 mm, 3 ov. F 2.9–3.0 mm (MNHN-IU-2013-9743).—Stn DB8, 15°34.6'S, 167°13.8'E, 12 m, 12 September 2006: 1 ov. F 3.0 mm (MNHN-IU-2013-9747), 5 M 2.4–3.0 mm, 5 ov. F 2.6–3.1 mm, 2 F 2.0– 2.4 mm (MNHN-IU-2013-15901), 1 M 3.0 mm (MNHN-IU-2013-9746).—Stn DB25, 15°37.7'S, 167°11.3'E, 10 m, 16 September 2006: 2 M 2.2–3.0 mm, 1 ov. F 2.8 mm (MNHN-IU-2013-15902).—Stn ED16, 15°35.3'S, 167°07.4'E, 5–7 m, 17 September 2006: 2 M 1.6–2.3 mm, 2 ov. F 3.0– 3.1 mm (MNHN-IU-2013-9748).—Stn DB33, 15°34.7'S, 167°13.8'E, 14–25 m, 18 September 2006: 5 M 1.8–3.6 mm, 5 ov. F 2.3–3.4 mm (MNHN-IU-2013-15903).—Stn DB40, 15°29.8'S, 167°15.1'E, 5 m, 19 September 2006: 2 M 2.4–2.6 mm, 2 ov. F 2.3–2.4 mm (MNHN-IU-2013-9752).—Stn DB46, 15°28.8'S, 167°15.2'E, 2–3 m, 20 September 2006: 5 M 3.3–3.5 mm, 15 ov. F 2.3–3.2 mm (MNHN-IU-2013- 15898).—Stn EP22, 15°37.3–37.4'S, 167°05.8–06.0'E, 78–91 m, 21 September 2006: 1 F 1.8 mm (MNHN-IU- 2013-9751).—Stn DB53, 15°28.8'S, 167°15.2'E, 5 m, 22 September 2006: 8 M 2.0– 3.8 mm, 9 ov. F 2.2–2.8 mm, 2 F 1.9–2.0 mm (MNHN-IU-2013-15896), 1 ov. F 2.5 mm (MNHN-IU-2013-9741).—Stn DB65, 15°25.8'S, 167°13.0'E, 13 m, 26 September 2006: 8 M 2.3–4.0 mm, 6 ov. F 2.0– 2.9 mm (MNHN-IU-2013-15906).—Stn DB67, 15°22.9'S, 167°13.1'E, 7 m, 26 September 2006: 10 M 2.0– 3.6 mm, 8 ov. F 2.2–3.3 mm (MNHN-IU-2013- 15894).—Stn DB75, 15°22.9'S, 167°11.9'E, 20 m, 28 September 2006: 10 M 2.0– 3.6 mm, 11 ov. F 2.8–3.3 mm (MNHN-IU-2013-15895).—Stn LD8, 15°22.3'S, 167°11.3'E, 2–4 m, 28 September 2006: 1 M 2.1 mm (MNHN- IU-2013-9744).—Stn FB40, 15°22.9'S, 167°11.7'E, 9 m, 29 September 2006: 1 M 3.7 mm, 4 ov. F 2.2–4.2 mm, 1 F 2.0 mm (MNHN-IU-2013-15904).—Stn LD12, 15°36.6'S, 167°11.3'E, 2–4 m, 30 September 2006: 3 M 3.0– 3.9 mm, 3 ov. F 2.8–3.4 mm (MNHN-IU-2013-15912).—Stn DB83, 15°43.4'S, 167°15.0'E, 6 m, 3 October 2006: 7 M 2.0–4.0 mm, 7 ov. F 2.7-3.4 mm, 2 F 2.0– 2.1 mm (MNHN-IU-2013-15907).—Stn LD14, 15°36.6'S, 167°10.5'E, 3–7 m, 3 October 2006: 1 M 3.0 mm, 3 ov. F 2.4–3.3 mm, 1 F 2.2 mm (MNHN-IU-2013-15900).—Stn DB86, 15°38.5'S, 167°15.1'E, 13 m, 4 October 2006: 9 M 2.0– 3.9 mm, 5 ov. F 2.2–3.3 mm, 1 F 3.0 mm (MNHN-IU-2013- 15909).—Stn FB52, 15°42.7'S, 167°15.1'E, 7 m, 5 October 2006: 7 M 2.4–2.8 mm, 4 ov. F 2.4–3.0 mm, 1 F 2.2 mm (MNHN-IU-2013-15905).—Stn FS51, 15°42.7'S, 167°15.1'E, 2–3 m, 5 October 2006: 3 M 1.6–3.2 mm, 1 ov. F 3.0 mm (MNHN-IU-2013-9753).—Stn ZB16, 15°32.4'S, 167°12.1'E, 5 m, 7 October 2006: 2 M 1.6–2.7 mm, 1 ov. F 2.1 mm (MNHN-IU-2013-9749).—Stn ZB20, 15°36.1'S, 167°05.4'E, 15–20 m, 10 October 2006: 2 ov. F 2.6- 2.7 mm (MNHN-IU-2013-9750).—Stn FB68, 15°35.4'S, 166°59.7'E, 11 m, 11 October 2006: 1 ov. F 2.3 mm (MNHN-IU-2013-9754).—Stn FB80, 15°33.1'S, 167°09.6'E, 2 m, 14 October 2006: 10 M 1.5–3.2 mm, 5 ov. F 2.0– 2.9 mm (MNHN-IU-2013-15908).—Stn FB92, 15°33.6'S, 167°16.6'E, 2–4 m, 14 October 2006: 3 M 1.5–3.7 mm, 1 ov. F 3.1 mm (MNHN-IU-2013-15893), 8 M 2.4–3.3 mm, 7 ov. F 2.0– 3.4 mm (MNHN-IU-2013-15910), 1 M 2.5 mm (MNHN-IU-2013-13987).—Stn FS96, 15°33.1'S, 167°09.6'E, 35 m, 14 October 2006: 2 M 2.2–2.4 mm, 1 ov. F 2.4 mm (MNHN-IU-2013-15911).—Stn VM69, 15°33.4'S, 167°16.7'E, 0–1 m, 18 October 2006: 1 M 3.5 mm (MNHN-IU-2013-9745).—Stn ZB36, 15°34.3'S, 167°12.4'E, intertidal, 19 October 2006: 5 M 2.5–3.4 mm, 7 ov. F 2.7–3.8 mm (MNHN-IU-2013-15897).

New Caledonia. Loyalty Islands. LIFOU, Stn 1463, 20°55.05’S, 167°03.35'E, 20–30 m, 10 November 2000: 1 M 3.0 mm (MNHN-IU-2013-9757).—Stn 1475, 20°55.8’S, 167°19.0’E, subtidal, 11 November 2000: 2 M 2.3–3.0 mm, 1 ov. F 3.6 mm, 1 F 2.5 mm (MNHN-IU-2013-15914).—Stn 1426, 20°45.9’S, 167°06.2’E, 4–7 m, 20 November 2000: 2 F 1.3–1.4 mm (MNHN-IU-2013-15917).—Stn 1418, 20°46.9 'S, 167°07.9 'E, 1–5 m, 21 November 2000: 3 M 2.3–3.3 mm (MNHN-IU-2013-9745).—Stn 1432, 20°53.5’S, 167°02.7’E, 12–32 m, 21 November 2000: 1 F 3.3 mm (MNHN-IU-2013-9756).—Stn 1453, 20°54.6’S, 167°02.1’E, 21–30 m, 22 November 2000: 1 M 2.3 mm (MNHN-IU-2013-15916).—Stn 1411, 20°47.6’S, 167°10.35’E, 48 m, 23 November 2000: 1 M 3.0 mm (MNHN-IU-2013-15915).—Stn 1410, 20°56.7’S, 167°03.1’E, 2–4 m, 25 November 2000: 1 M 3.0 mm, 1 ov. F 3.5 mm (MNHN-IU-2013-15919).—Stn 1455, 20°56.8’S, 167°02.7’E, 15–20 m, 25 November 2000: 1 M 3.7 mm (MNHN-IU-2013-9742).—Stn 1421, 20°52.4’S, 167°08.5’E, 4 m, 26 November 2000: 19 M 2.0– 4.1 mm, 11 ov. F 2.4–3.4 mm, 12 F 2.0– 4.3 mm (MNHN-IU-2013-15913).—Stn 1457, 20°46.8’S, 167°02.75’E, 5–10 m, 27 November 2000: 1 M 2.4 mm (MNHN-IU-2013-15918).—MUSORSTOM 6, Stn DW431, 20°22.25'S, 166°10.00'E, 21 m, 18 February 1989: 1 M 3.0 mm, 4 ov. F 3.0– 3.2 mm (MNHN-IU-2013-15930).—Stn DW434, 20°21.21'S, 166°08.64'E, 23 m, 18 February 1989: 1 M 2.2 mm (MNHN-IU-2013-15925).

Lagon North. Stn 483, 19°01'S, 163°32'E, 33 m, 2 March 1985: 2 M 2.8–3.5 mm, 3 ov. F 2.0– 3.1 mm (MNHN- IU-2013-15922).—Stn DW1120, 19°36.5'S, 163°45.3'E, 47 m, October 1989: 1 M 2.7 mm, 1 F 2.4 mm (MNHN- IU-2013-15926).

Lagon, Ounia, intertidal, 14 October 1978: 1 ov. F 3.7 mm (MNHN-IU-2013-15920).—Laragnere Reef, Stn 1371, 12– 16 m: 1 M 3.8 mm (MNHN-IU-2013-15927).—Plouveal. Stn DW1223, 20°28.0'S, 166°28.0'E, 19 m, 12 September 1992: 1 M 3.4 mm, 1 ov. F 3.5 mm (MNHN-IU-2013-15923).— Stn DW1231, 23 m: 1 M 2.4 mm, 1 ov. F 2.9 mm (MNHN-IU-2013-15929), 1 M 3.6 mm (MNHN-IU-2013-15928).—Isle of Pines, August 1993: 1 M 3.7 mm (MNHN-IU-2013-15921).—Touho, 20°47'S, 165°13'E, intertidal, 7 September 1993: 3 M 2.6–2.8 mm, 4 ov. F 2.8–3.0 mm (MNHN-IU-2013-15928).

Etymology. Acis was the lover of the sea-nymph Galathea . The name is considered as a substantive in apposition.

Description. Carapace: As long as broad; dorsal surface nearly horizontal from anterior to posterior; posterior cervical groove distinct, but anterior cervical groove indistinct. 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; 1 protogastric ridge uninterrupted and extending laterally to second anterolateral spine, laterally interrupted in some specimens; 1 mesogastric ridge uninterruptedly extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, not extending laterally to anterior branchial ridges, posterior ridge short, sometimes absent. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges, 1 or 2 of them uninterrupted. Lateral margins medially convex, with 8 spines: 2 spines in front of and 6 spines behind indistinct anterior cervical groove (defined here by the mesogastric ridge); first anterolateral, welldeveloped, at level of lateral 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 spine small. External limit of orbit unarmed or with small spine, with well-developed frontal spine between external limit of orbit and first anterolateral spine, infra-orbital margin with strong spine. Rostrum broadly triangular, 1.3–1.4 times as long as broad, 0.5–0.6 length of carapace and 0.3–0.4 of carapace width, distance between distalmost lateral incisions 0.3 of distance between proximalmost lateral incisions, dorsal surface slightly concave medially; lateral margin with 4 deeply incised teeth.

Pterygostomian flap rugose, with 1 distinct spine on upper margin near linea anomurica, anterior margin ending in well-developed spine; no facial 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 peduncle 1.2–1.3 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 23–26 denticles. Merus shorter than ischium, with strong proximal spine on flexor margin, located at midlength, and not reaching distal margin of merus, sometimes 1 small additional spine; extensor margin with distal spine. Carpus spineless.

P1: 2.3–2.5 times carapace length, moderately stout, 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, 1.4–1.5 times as long as carpus, with rows of spines, mesial and distal spines particularly strong. Carpus slightly shorter than palm, 1.7–1.9 times longer than broad, lateral and mesial margins subparallel, dorsal surface with small spines; mesial surface with row of 3 or 4 prominent spines; and row of small spines along lateral margin. Palm 1.4–1.8 times longer than broad; spines 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 2 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 1.7 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.9 length of P3 merus); P2 merus 0.6–0.7 carapace length, 2.9–3.2 times as long as broad, 1.6 times longer than P2 propodus; P3 merus 3 2.7 times as long as broad, 1.4 times length of P3 propodus; P4 merus 2.8 times as long as broad, 1.2 times length of P4 propodus; extensor margins each with row of 7–9 proximally diminishing spines in P2–3, 0–2 distal spines in P4; lateral surface unarmed in P2–3, 1–3 spines in P4; 1 or 2 well-developed spines on flexor distal margin, sometimes obsolescent in P4; flexormesial margin with terminal spine in P2 only. Carpi each with 4 or 5 spines on extensor margin in P2–3, 0–1 minute spine in P4; lateral surface with row of 2–4 acute granules or spines paralleling extensor row in P2–3, obsolescent in P4. Propodi 3.0–3.5 times as long as broad in P2–4; extensor margins each with 2 or 3 proximal spines in P2–3, unarmed in P4; flexor margins each with 4 slender movable spines in P2–4; lateral surface unarmed. Dactyli 0.6–0.8 length of propodi, ending in incurved, strong, sharp spine; flexor margins each with prominent triangular terminal tooth preceded by 4 low teeth.

Epipods absent on pereiopods.

Coloration: Ground color of carapace, abdominal somites 2–4 and pereopods reddish, with darker transverse ridges; some whitish patches scattered on surfaces of carapace and abdomen. Distal part of P1 palm and proximal portion of P1 fingers whitish; one distinct black spot on distal part of P1 palm. P2–4 with reddish and whitish transverse bands. One specimen collected in Papua New Guinea showed a ground color of carapace and abdomen whitish, with numerous dark spots.

Remarks. Galathea acis belongs to the group of species characterized by the pterygostomian flap with one or two spines on the upper margin near the linea anomurica, and an uninterrupted mesogastric ridge between the anteriormost branchial marginal spines. The new species resembles G. mauritiana Bouvier, 1914 and related species, e.g., G. aequata n. sp., G. ahyongi n. sp., G. s e n t a n. sp. (see also Remarks for G. mauritiana ). The closest relative of G. acis is G. aequata n. sp. from French Polynesia, and these two species are easily distinguished by the number of movable spinules along the flexor margin of the propodi P2–3: 5 or 6 in G. aequata and 4 in G. acis . No other constant morphological differences were observed.

The genetic divergence between the two species is 16.0% (COI) (no data of 16S rRNA is available).

The new species has probably been cited (as G. mauritiana or G. affinis , see below) in the western Pacific. Unfortunately, only the material from Gorong Islands ( Baba 1979b) has been re-examined, and agrees quite well with the present material. Other occurrences from the distribution area of G. a c i s are dubious and need reexamination.

Distribution. The existence of new cryptic species, closely related to G. mauritiana Bouvier, 1914 , suggests that previous records should be considered with caution. Galathea acis is known with certaintly from Japan (Ryukyu Islands), Mariana Islands ( Guam), Papua New Guinea, Samoa, Australia, Christmas Islands, Queensland, Vanuatu, and New Caledonia, 0– 91 m.

Figures

FIGURE 3. Galathea acis n. sp., holotype, male, 3.7 mm, Vanuatu (MNHN-IU- 2013 - 15899). 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, right P 2 propodus and dactylus, lateral view; H, right P 3, lateral view; I, right P 4, lateral view. Scale: A, E, F, H, I = 1 mm; B – D, G = 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).