Galathea peitho, 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 : 225-228

Galathea peitho n. sp.

( Figs 81 , 118 I)

Material examined. Holotype: Australia. Queensland, Lizard Island, off North Point, 30 m, 25 February 2009: ov. F 4.4 mm (QM W29209).

Paratypes: Japan. Ryukyu Islands. Iriomote Island, Nakano Beach, 24.4323°N, 123.7916°E, 19 m, 9 July 2010: 1 M 2.2 mm, 1 ov. F 2.5 mm, 2 juv. 1.2–1.3 mm (UF26912).—Okinawa Island, Uruma, Tengan Pier, 26.4063°N, 127.8501°E, 0–12 m, 19 July 2010: 1 ov. F 4.0 mm (UF29328).

Mariana Islands. Guam Island, Apra Harbor, 13.435°N, 144.663°E, no depth, 22 June 2010: 1 M 2.0 mm (UF26724).

Papua New Guinea. PAPUA NIUGINI, Stn PR22, 05°17.8'S, 145°46.9'E, 3–10 m, 12 November 2012: 2 M 2.6–2.7 mm (MNHN-IU-2013-13507).—Stn PD32, 05°04.4'S, 145°48.7'E, 1–8 m, 17 November 2012: 1 F 3.0 mm (MNHN-IU-2013-721).—Stn PB03, 05°11.5'S, 145°49.1'E, 15 m, 30 December 2012: 3 M 2.0– 3.7 mm, 3 ov. F 2.1–2.8 mm (MNHN-IU-2013-142).—Stn PB06, 05°09.9'S, 145°50.4'E, 20 m, 30 December 2012: 1 M 2.6 mm, 2 ov. F 2.5–3.3 mm (MNHN-IU-2013-13504).—Stn PB08, 05°11'S, 145°48.4'E, 4–5 m, 30 December 2012: 2 ov. F 2.2–3.0 mm (MNHN-IU-2013-13509).—Stn PB11, 05°12.5'S, 145°49.1'E, 13 m, 30 December 2012: 2 ov. F 3.0– 3.2 mm (MNHN-IU-2013-13505).—Stn PB12, 05°11.8'S, 145°48.8'E, 7–15 m, 30 December 2012: 1 M 4.0 mm (MNHN-IU-2013-372); 3 ov. F 3.0– 3.5 mm (MNHN-IU-2013-13512).—Stn PB15, 05°04.7'S, 145°48.9'E, 5 m, 30 December 2012: 1 M 2.7 mm (MNHN-IU-2013-709); 3 M 2.1–3.3 mm, 3 ov. F 2.7–3.3 mm (MNHN-IU- 2013-13506).—Stn PB26, 04°59.1'S, 145°47.7'E, 22 m, 30 December 2012: 1 M 3.2 mm, 1 F 2.5 mm (MNHN-IU- 2013-13508).—Stn PB31, 05°09.4'S, 145°50'E, 31 m, 30 December 2012: 3 M 2.0– 3.3 mm, 1 ov. F 2.3 mm (MNHN-IU-2013-13510).—Stn PS31, 05°08.167'S, 145°49.417'E, 10–37 m, 30 December 2012: 1 M 1.8 mm (MNHN-IU-2013-13511).

Australia. Western Australia, Dirk Herlog Island, 30–40 m, 1 March1999: 2 M 3.8–4.1 mm (UF5155).

Australia. Queensland, Stn AIMS 17, 18°17'S, 146°38'E, no date: 1 M 3.1 mm, 3 ov. F 2.8–3.6 mm (AM- J13333 ). Queensland, Lizard Island, 14.6966°S, 145.4642°E, 4–8 m, 8 February 2009: 1 M 3.8 mm (UF16671).— 14.3902°S, 145.2737°E, 10–12 m, 9–13 February 2009: 1 M 2.8 mm (UF16677); 1 M 4.4 mm (UF16678); 1 M 4.6 mm (UF16681); 2 M 3.3–4.2 mm, 4 ov. F 3.6–4.5 mm, 1 F 2.7 mm (UF16685); 4 M 1.8–3.4 mm (UF16693); 3 M 3.2–4.9 mm, 5 ov. F 3.5–4.4 mm (UF16719); 8 M 3.0– 4.6 mm, 6 ov. F 2.7–4.5 mm (UF16728); 6 M 2.6–4.3 mm, 5 ov. F 3.3–4.2 mm (UF16776); 5 M 3.0– 5.4 mm, 3 ov. F 4.2–4.5 mm (UF16777); 9 M 2.0– 3.4 mm, 3 ov. F 3.0– 4.8 mm (UF16835); 6 M 2.4–4.3 mm, 3 ov. F 4.2–4.4 mm, 1 F 1.6 mm (UF16866); 4 M 1.6–4.2 mm, 7 ov. F 3.3–4.7 mm, 3 F 2.0– 2.3 mm (UF16911); 7 M 2.2–4.3 mm, 10 ov. F 3.1–4.5 mm, 1 F 3.2 mm (UF16914); 1 M 4.2 mm (UF16796); 1 M 4.0 mm (UF16682); 1 M 4.8 mm (UF16679). Day Reef, 22 February 2009: 1 F 1.7 mm (UF17372).—off North Point, 30 m, 25 February 2009: 6 M 2.8–4.6 mm, 7 ov. F 2.8–4.4 mm, 2 F 2.6–2.8 mm (UF17565); 1 M 4.2 mm (UF17586).— 14.6515°S, 145.4607°E, no depth, 17 February 2009: 1 M 3.6 mm (UF18208); 3 M 2.0– 2.5 mm, 1 F 1.8 mm (UF18213); 1 F 1.8 mm (UF18212); 3 M 2.0– 2.1 mm (UF18207).— 14.6504°S, 145.4621°E, no depth, 18 February 2009: 4 M 2.0– 3.7 mm, 1 M 2.1 mm (UF18238); 3 M 1.6–2.2 mm, 1 F 1.4 mm (UF18230); 4 M 2.0– 3.7 mm, 1 M 2.1 mm (UF18238).— 14.6564°S, 145.4956°E, no depth, 19 February 2009: 1 M 2.1 mm (UF18251).— 14.6504°S, 145.4621°E, no depth, 20–21 February 2009: 5 M 1.4–2.2 mm (UF18262); 2 M 1.3–2.0 mm, 1 F 1.8 mm (UF18276); 4 M 1.7–3.6 mm, 3 F 1.7–1.8 mm (UF18305); 5 M 1.4–2.2 mm (UF18262); 2 M 1.3–2.0 mm, 1 F 1.8 mm (UF18276); 1 M 3.0 mm (UF18265).— 25–30 m, 22 February 2009: 1 F 1.7 mm (UF17372). Queensland, Bird Island, 14.6926°S, 145.4684°E, no depth, 22–23 February 2009: 4 M 1.5–4.2 mm, 1 ov. F 3.6 mm, 2 F 1.7–1.8 mm (UF18336); 1 M 4.2 mm, 3 ov. F 3.0– 3.8 mm (UF18351); 1 ov. F 3.2 mm (UF18360); 4 M 1.5–4.2 mm, 1 ov. F 3.6 mm, 2 F 1.7–1.8 mm (UF18336). Heron Island, 23.4733°S, 151.9505°E, 17 November 2006: 1 ov. F 3.5 mm (UF25217); 1 F 2.0 mm (UF25214).

Etymology. Peitho , persuasion, is one of the children of the Ocean in Greek mythology. The name is considered as a substantive in apposition.

Description. Carapace: as long as broad; ridges with dense short and moderately long non-plumose setae; cervical groove distinct, laterally bifurcated; ridges on gastric and anterior branchial regions scale-like or in concentric arcs; epigastric region with 2–4 median spines; 2 small spines on median protogastric scale-ridge; 1 parahepatic and 1 anterior branchial spine on each side. Mid-transverse ridge laterally interrupted, preceded by shallow cervical groove, followed by 5 ridges, with 2 laterally interrupted transverse ridges; scale-like ridges between mid-transverse and first transverse ridge, and between first and second transverse ridges. Lateral margins slightly convex medially, with 8 spines: 2 spines in front of and 6 spines behind anterior cervical groove; first anterolateral, second spine very small, additional spine ventral to between first and anterior branch of cervical groove; 3 spines on anterior branchial margin, and 3 spines on posterior branchial margin, last smaller than others. External orbital limit ending in small spine; infraorbital margin with 1 strong spine, sometimes 1 or 2 additional minute spines; 1 small frontal spine between lateral orbital spine and first anterolateral spine, absent in some specimens. Rostrum moderately elongate, triangular, 1.3–1.4 times as long as broad, 0.6 carapace length and breadth 0.4 that of carapace, nearly horizontal in lateral view; distance between distalmost lateral incisions 0.25 distance between proximalmost lateral incisions; dorsal surface with small setiferous ridges; lateral margin with 4 deeply incised sharp teeth.

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

Sternum: Plastron slightly broader than long, lateral extremities gently divergent posteriorly.

Abdomen: Somite 2 with 2 transverse ridges on tergite, anterior ridge more distinctly elevated than posterior ridge; somites 3–4 smooth, with anterior ridge only; somites 5–6 smooth, posteromedian margin of somite 6 straight. Males with G1 and G2.

Eyes: Ocular peduncles 1.5 times longer than broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with 3 well-developed spines, distodorsal larger; distomesial spine somewhat smaller and more slender than distolateral. Ultimate article with tuft of fine setae on distodorsal margin.

Antenna: Article 1 with ventral distomesial spine exceeding distal margin of article 2. Article 2 with 2 welldeveloped distal spines, distolateral spine slightly longer than distomesial and exceeding midlength of article 3. Article 3 with small distomesial spine. Article 4 unarmed.

Mxp3: Ischium with extensor and flexor margins without distinct distal spine; crista dentata with 22–24 denticles. Merus shorter than ischium; flexor margin with 2 strong spines of subequal size, proximal one located at midlength, distal one at terminal end; extensor margin ending in small spine or acute angle. Carpus unarmed.

P1: 3.0–3.2 times carapace length, with numerous short unirramous setae and some long plumose and nonplumose setae; setae non iridescent. Merus 1.2 times length of carapace, 1.5–1.6 times as long as carpus, with spines arranged roughly in rows, mesial and distal spines prominent. Carpus as long as palm, 2.0–2.1 times as long as broad; dorsal surface with spines arranged roughly in longitudinal rows; mesial margin with 3or 4 strong spines, distal second largest. Palm 1.6–1.8 times longer than broad, lateral and mesial margins subparallel; spines arranged roughly in rows, dorsolateral row of spines continued on to whole lateral margin of fixed finger. Fingers 0.9 length of palm, each finger with two rows of teeth distally spooned; movable finger with spines along mesial margin.

P2–4: Moderately slender, with sparse long plumose and non-plumose setae; setae non inridiscent. P2 2.0–2.1 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 0.8 carapace length, 3.2 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 3.0 times longer than broad, 1.2–1.3 times longer than P3 propodus; P4 merus 2.9 times as long as broad, 1.0–1.2 length of P4 propodus. Extensor margins with row of 8–10 proximally diminishing spines on P2–3, 2–4 on P4; lateral surface with 1 or 2 small spines on P4; distoflexor margin ending in 1 spine, followed proximally by small spines and several tubercles or eminences. Carpi with 3–5 spines on extensor margin on P2–3, unarmed or ending in 1 spine on P4; lateral surface with 4 or 5 spines or acute granules sub-paralleling extensor margin on P2–4; flexor distal margin with small distal spine. Propodi 4.3–4.5 times as long as broad; extensor margin with 2–4 spines on proximal half on P2 and P3, 1 or 2 proximal spines on P4; flexor margin with 3–5 slender movable spines. Dactyli distally ending in well-curved strong spine, 0.5–0.6 length of propodi; flexor margin with 4 or 5 proximally diminishing teeth.

Epipods present on P1–3.

Coloration. Translucent brownish or greenish overall. Rostrum reddish or greenish. Tips of rostral and carapace spines red; Carapace ridges reddish. Abdominal somites 2–4 with longitudinal one whitish stripe on each side. P1 with distal part of merus, carpus and palm with white spots; proximal part of cutting edges of P1 fingers white. P2–4 with diffuse reddish bands. P1–4 spines red.

Remarks. Galathea peitho n. sp. belongs to the group of species characterized by the possession of scale-like ridges on the gastric region of the carapace, epipods on P1–3, the presence of at least one dorsal spine on the anterior branchial region, and the absence of postcervical spines. It is most closely related to G. aculeata Haswell, 1882 from Queensland. The two species can be differentiated by the following characters:

- The carapace is clearly longer than broad in G. aculeata , rather than as long as broad in G. peitho .

- The transverse ridges of the posterior half of the carapace are laterally interrupted in G. p e i t h o, whereas these ridges are uninterrupted in G. aculeata .

- The rostrum is more than 1.5 times longer than broad in G. a c u l e a t a, whereas it is less than 1.5 times longer than broad in G. peitho .

- The P2–4 propodi are more than 4 times as long as broad in G. peitho , while 4 times as long in G. a c u l e a t a.

The two species are also close to G. polydora n. sp. from Indonesia, Vanuatu, New Caledonia, Chesterfield Islands, and Fiji (see the Remarks of G. polydora ).

Galathea peitho is also genetically close to G. l e p o r i s n. sp. from Indonesia, Papua New Guinea, Vanuatu, and New Caledonia, 7.2 % (COI) and 12.1% (16S rRNA) ( Tab. 3 ). However, the two species are easily distinguished by the presence of one spine between the anterolateral spine and the the anteriormost btanchial marginal spine in G. leporis , that is absent in G. peitho . Furthermore, the epipods are present on P 1–3 in G. peitho , instead of only on P 1 in G. leporis .

Distribution. Japan. Okinawa, Mariana Islands, Papua New Guinea, Australia (Western Australia, Queensland); 0– 37 m.

Figures

FIGURE 81. Galathea peitho n. sp., holotype, ovigerous female, 4.4 mm, Australia, Queensland (QM W 29209). A, carapace and abdomen, dorsal view; B, thoracic sternites 3 and 4; C, right pterygostomian region, lateral view; D, left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap; E, ischium, merus and carpus of right Mxp 3, lateral view; F, right P 1, dorsal view; G, right P 2, lateral view; H, right P 3, lateral view; I, right P 4, lateral view (setae on appendages not figured). Scale: A, C, G, H, I = 1 mm; F = 2 mm; B, D, E = 0.5 mm.

FIGURE 118. Dorsal view. A, Galathea maculiabdominalis Baba, 1972, Vanuatu, male 2.4 mm (MNHN-IU- 2013 - 8344). B, Galathea mariae n. sp., French Polynesia, ovigerous female 3.0 mm (UF 15523). C, Galathea mauritiana Bouvier, 1914, Madagascar, female 2.5 mm (IU- 2013 - 9740). D, Galathea minima n. sp., Papua New Guinea, ovigerous female 2.8 mm (MNHN-IU- 2013 - 704). E, Galathea minima n. sp., Papua New Guinea, ovigerous female 2.5 mm (MNHN-IU- 2013 - 654). F, Galathea ohshimai Miyake & Baba, 1967, Vanuatu, male 2.2 mm (MNHN-IU- 2013 - 13881). G, Galathea parvula n. sp., holotype, ovigerous female 2.9 mm (UF 38286). H, Galathea paulayi n. sp., French Polynesia, male 4.7 mm (UF 15618). I, Galathea peitho n. sp., Papua New Guinea, male 4.0 mm (MNHN-IU- 2013 - 372).