Galathea tongi, 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 : 310-312

Galathea tongi n. sp.

( Figs 110 , 121 F)

Material examined. Holotype: Kiribati. Line Islands. Tabuaeran Atoll, 3.8051°N, 159.3021°W, 10–23 m, 13 August 2005: ov. F 3.1 mm (UF10707).

Paratypes: Mariana Islands. Agriham Island, 8 m, 30 May 1992: 1 M 2.5 mm, 1 F 2.6 mm (UF2598).—Agrihan Island, reef slope, 20 m, 30 May 1992: 1 ov. F 3.0 mm (UF2601).— Guam Island. 13.5167°N, 144.8°E, 10–25 m, 27 June 2003: 1 M 2.8 mm (UF4173).— Guam Island. East Agana Bay, 1 m, 1 February 1997: 1 F 2.8 mm (UF319).— Guam Island: 1 M 2.3 mm (UF27250).

Kiribati. Line Islands. Tabuaeran Atoll, SSW side of atoll, 3.8051°N, 159.3021°W, 10–23 m, 13 August 2005: 3 M 2.1–3.3 mm, 3 ov. F 2.1–2.2 mm (UF10682).—3.8681°, 159.3742°, 10.5 m, 15 August 2005: 1 M 3.4 mm, 1 ov. F 2.7 mm (UF10728); 1 ov. F 2.7 mm (UF10733); 1 F 2.7 mm (UF10726). Kingman Reef, 6.3796°N, 162.3648°W, 12 m, 28 August 2005: 1 F 2.1 mm (UF10727).— 6.3801°N, 162.4137°W, 10.5 m, 30 August 2005: 1 ov. F 3.2 mm (UF10453). Palmyra Atoll, 5.8693°N, 162.0757°W, 9–15 m, 18 August 2005: 1 ov. F 2.9 mm (UF10699).—Milennium Island, 9.91°S, 150.21°W, 7 m, 6 November 2013: 1 F 1.9 mm, 1 juv. 1.6 mm (UF38490), 1 ov. F 3.3 mm (UF3869).— 29.91°S, 150.21°W, 12 m, 5 November 2013: 1 M 2.8 mm, 1 F 2.5 mm (UF39426).—Starbuck Island, 5.64°S, 155.88°W, 1 m, 26 October 2013: 2 M 2.7–2.8 mm, 2 F 2.3–2.5 mm (UF39147).— 5.64°S, 155.88°W, 16 m, 26 October 2013: 16 M 2.7–4.0 mm, 13 ov. F 3.1–3.9 mm, 5 F 2.3–2.8 mm (UF39399).—Fint Island, 11.4311°S, 151.8248°W, 10 m, 18 October 2013: 1 M 3.3 mm (UF39179), 7 M 1.8–3.8 mm, 9 ov. F 2.6–3.9 mm, 5 F 1.8–2.7 mm (UF39430).

French Polynesia. Tuamotu Archipelago. Hao Atoll, 18.0826°S, 141.068°W, 34 m, 17 January 2013: 1 M 2.0 mm (UF35298). Tenarunga Atoll, 21.3562°S, 136.531°W, 14.6 m, 25 January 2013: 1 M 2.2 mm (UF35363). Society Islands. Moorea Island, 17.4764°S, 149.8306°W, 5–20 m, 18 July 2006: 1 F 2.1 mm (UF9923).— 17.4836°S, 149.8581°W, 22 m, 24 July 2006: 1 M 3.2 mm (UF9758).— 17.479°S, 149.7643°W, 29 m, 17 October 2008: 1 M 2.8 mm (UF15696); 1 ov. F 3.0 mm (UF15686).— 17.568°S, 149.884°W, 22 m, 20 October 2008: 1 ov. F 3.2 mm (UF15911).— 17.487°S, 149.8772°W, 5–7 m, 10 November 2009: 1 F 2.6 mm (UF23958).— November 2009: 1 F 1.8 mm (UF24135). Gambier Islands. Temoe Atoll, 23.3574°S, 134.4934°W, 21 m, 9 February 2013: 1 M 1.9 mm (UF35516); 1 M 1.7 mm (UF35517).— 23.329°S, 134.506°W, 20 m, 9 February 2013: 1 M 2.6 mm (UF35524).

Etymology. This species is dedicated to the President Anatole Tong of Kiribati, for his global leadership in ocean conservation.

Description. Carapace: slightly broader than long; dorsal surface nearly horizontal from anterior to posterior; transverse ridges with dense short setae, and some moderately long simple setae; cervical groove distinct, laterally bifurcated. Gastric region with 5 transverse ridges: 1 epigastric ridge medially interrupted, with 2 spines; 2 mesogastric ridges, anterior ridge medially interrupted by 1 arcuate scale (very rarely uninterrupted), posterior one scale-like; 2 metagastric scale-like ridges. One small parahepatic spine, and one hepatic spine, near anterolateral spine, on each side. Anterior branchial region with distinct scale-like ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 3 or 4 ridges, two of them uninterrupted. Lateral margins slightly convex, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, welldeveloped, at same level of lateral limit of orbit, second small, with spine ventral to between first and second spines; 2 spines on anterior branchial region, and 3 spines on posterior branchial margin, last small. Spine on lateral limit of orbit, 1 small spine between orbital and anterolateral spine in some specimens; infraorbital margin with strong spine. Rostrum 1.3 as long as broad, length 0.6 postorbital carapace length and breadth 0.4 that of carapace; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface nearly horizontal in lateral view, with some short setae; lateral margin with 4 deeply incised sharp teeth.

Pterygostomian flap rugose, unarmed, ridges with short setae, anterior margin acute.

Sternum: 0.9 times as long as broad, lateral extremities gently divergent posteriorly.

Abdomen: Somites 2–3 with 2 transverse uninterrupted ridges; somites 4–6 smooth; somite 6 with posteriomedian margin straight. Males with G1 and G2.

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.7 rostrum width.

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

Antenna: Article 1 with ventral distomesial spine reaching distal margin of article 2. Article 2 with 2 subequal distal spines, barely reaching midlength of article 3. Article 3 with small distomesial spine. Article 4 unarmed.

Mxp3: Ischium with small spine on flexor and extensor distal margins; crista dentata with 22–25 denticles. Merus shorter than ischium; flexor margin with 2 subequal well-developed spines; extensor margin with 2 spines. Carpus with 2 or 3 granules along extensor margin.

P1: 2.9 times carapace length, covered with finely setiferous scales, with numerous long simple setae (not figured). Merus as long as carapace, 1.7 times as long as carpus, with spines arranged roughly in rows, dorsomesial spines stronger; distal spines prominent. Carpus as long as palm, 1.9–2.0 times as long as broad; dorsal and lateral surfaces with some spines; mesial margin with 3 or 4 spines (distal second strong). Palm twice longer than broad, lateral and mesial margins subparallel; spines arranged roughly in dorsolateral and dorsomesial rows, continuing along fixed and movable fingers, respectively; a few small spines scattered on dorsal side. Fingers as long as palm, each finger distally with two rows of teeth, spooned.

P2–4: moderately slender, with setose striae and sparse long plumose setae. P2 equal or less than twice carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P3 merus, P4 merus 0.8 length of P2 merus); P2 merus 0.8 carapace length, 2.8 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 3.4 times as long as broad, 1.3 times longer than P3 propodus; P4 merus 2.7 times as long as broad, as long as P2 propodus. Extensor margin of P2–3 meri with row of 6–9 proximally diminishing spines, 5 spines on P4; ventral margins distally ending in strong spine followed proximally by 0–1 spines and several eminences; lateral sides unarmed. Carpi with 4 or 5 spines on extensor margin on P2–3, 1–3 spines on P4; lateral surface with 2–4 small spines or acute granules sub-paralleling extensor margin; flexor distal margin acute. P2–4 propodi 4.4–4.5 times as long as broad; extensor margin with 3–5 proximal spines on P2–4; flexor margin with 4 or 5 slender movable spines. Dactyli distally ending in well-curved strong spine, length 0.5 that of propodi; flexor margin with 4 or 5 proximally diminishing teeth, terminal one prominent.

Epipods present on P1.

Coloration. Base color translucent whitish or light orange, with numerous minute red spots on carapace and abdomen. Carapace with some whitish bands on each branchial region. P1 with reddish band on distal part of merus, carpus and palm; finger cutting edges whitish; spines red. P2–4 each with distal red band on merus and white band on distal part of propodus; spines red.

Remarks. Galathea tongi n. sp. is closely related to G. l e p o r i s n. sp. from Indonesia, Papua New Guinea, Vanuatu, and New Caledonia, from which it can be distinguished by the following characters:

- The P2 merus is 3 times longer than broad in G. tongi , instead of 4 times in G. leporis .

- The P2 is twice or less than twice as long as the carapace in G. tongi , rather than more than twice in G. leporis . - The genetic divergences between G. tongi and G. leporis are 18.2 % (COI) and 13.4% (16S rRNA) ( Tab. 2 ).

Distribution. Mariana Islands, Kiribati (Line Islands), French Polynesia (Gambier Islands, Society Islands, Tuamotu Archipelago), 1– 34 m.

Figures

FIGURE 110. Galathea tongi n. sp., holotype, ovigerous female, 3.3 mm, Kiribati, Line Islands (UF 10707). A, carapace and abdomen, dorsal view; B, sternal plastron; 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 3, lateral view; H, right P 4, lateral view (setae not figured). Scale: A, E – H = 1 mm; B – D = 0.5 mm.

FIGURE 121. Dorsal view. A, Galathea subsquamata Stimpson, 1858, Papua New Guinea, male 3.4 mm (MNHN-IU- 2013 - 353). B, Galathea tagaloa n. sp., Vanuatu, M 6.5 mm (MNHN-IU- 2013 - 13983). C, Galathea tagaro n. sp., Vanuatu, holotype, female 4.7 mm (MNHN-IU- 2013 - 8365). D, Galathea tanegashimae Baba, 1969, Papua New Guinea, male 2.3 mm (MNHN- IU- 2013 - 375). E, Galathea ternatensis De Man, 1902, Papua New Guinea, male 3.5 mm (MNHN-IU- 2013 - 13664). F, Galathea tongi n. sp., French Polynesia, ovigerous female 3.0 mm (UF 15686).