Galathea caesariata, 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 : 72-74

Galathea caesariata n. sp.

( Figs 20 , 116 B)

Material examined. Holotype: Vanuatu. SANTO, Stn AT28, 15°23.6'S, 167°16.1'E, 342–350 m, 23 September 2006: 1 M 5. 1 mm (MNHN-IU-2013-15938).

Paratypes: Papua New Guinea. PAPUA NIUGINI, Stn CP4023, 05°22'S, 145°48'E, 340–385 m, 14 December 2012: 1 M 5.0 mm (MNHN-IU-2013-13973).

New Caledonia. BATHUS 1, Stn CP707, 21°42'S, 166°35'E, 347–375 m, 19 March 1993: 1 ov. F 3.8 mm (MNHN-IU-2013-13942). BATHUS 4, Stn CP899, 20°16.68'S, 163°50.26'E, 500–600 m, 3 August 1994: 1 M 6.0 mm (MNHN-IU-2013-13960).

Etymology. From the Latin caesariatus, covered with hair, in reference to the hairy aspect of the species.

Description. Carapace: 1.2 times as long as broad; transverse ridges with numerous short fine setae; cervical groove distinct, laterally bifurcated; most ridges on gastric region uninterrupted, with some scattered scale-like ridges; 1 epigastric ridge, with 8 or 9 spines; 2 protogastric ridges, anterior ridge with 1 or 2 small parahepatic spines on each side; 2 mesogastric ridge, anterior one not extending to anteriormost marginal branchial spine, posterior ridge scale-like; 2 or 3 metagastric ridges, anterior one not extending to anterior branchial ridges. Each hepatic region with 1 or 2 small spines. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 4 uninterrupted and 3 interrupted transverse ridges. Lateral margins slightly convex medially, with 9 spines: 2 spines in front of and 7 spines behind anterior cervical groove; first spine anterolateral, well-developed, behind level of orbit, second very small but distinct, located at midlength between first spine and anteriormost spine of branchial margin, with small spine ventral to between first and second; 4 spines on anterior branchial margin, and 3 spines on posterior branchial margin. Small outer orbital spine and 2 small frontal spines between orbital and first anterolateral spines; infraorbital margin with 2 strong spines. Rostrum triangular, twice longer than broad, length 0.5 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 setose scales; 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 2–3 each with 3 or 4 uninterrupted transverse ridges on tergite, anterior ridge slightly more elevated than posterior ridge; somites 4–5 each with 2 uninterrupted ridges; somite 6 with 2 medially interrupted ridges, posteromedian margin straight. Males with G1 and G2.

Eyes: Ocular peduncles 1.3 times longer than broad, maximum corneal diameter 0.9 rostrum width.

Antennule: Article 1 with 2 well-developed distodorsal and distolateral spines, distodorsal larger; distomesial spine obsolescent; 1 small spine on lateral margin. Ultimate article with a tuft of fine setae on distodorsal margin.

Antenna: Article 1 with distomesial spine barely reaching distal margin of article 2. Article 2 with 2 welldeveloped 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 20–22 denticles. Merus as long as ischium; flexor margin with 3 spines, proximal stronger than others; extensor margin with 1 or 2 spines, distal spine well-developed. Carpus unarmed.

P1: 4.2 times carapace length, with numerous finely setiferous scales, with scattered long thick non-plumose setae. Merus twice length of carapace, 2.0 times as long as carpus, with spines arranged roughly in rows, dorsomesial and ventromesial spines stronger; distal spines prominent. Carpus 0.7 length of palm, 3.1 times as long as broad; dorsal surface with small spines arranged roughly in 2 longitudinal rows; mesial row of small spines. Palm 3.0 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 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 long non-plumose setae. P2 2.6 times carapace length. Meri successively shorter posteriorly (P3 merus 0.7 length of P2 merus, P4 merus 0.7 length of P3 merus); P2 merus 1.1 carapace length, 7.8 times as long as broad, 1.2 times longer than P2 propodus; P3 merus 5.0 times longer than broad, 1.0–1.1 times longer than P3 propodus; P4 merus 3.6 times as long as broad, 0.8 length of P4 propodus. Extensor margins of meri with row of 11–14 proximally diminishing spines on P2–3, 7 spines on P4; flexor margins distally ending in strong spine followed proximally by 6 or 7 small spines on P2, and 1 or 2 spines and several tubercles or eminences on P3–4; lateral sides with some minute spines on P2–4. Carpi with 6–8 spines on extensor margin, distalmost longer than distal second; lateral surface with 4 or 5 small spines and acute granules sub-paralleling extensor margin on P2–4; flexor distal margin with small spine. P2-4 propodi 8.0 (P2), 9.0 (P3) and 7.0 (P4) times as long as broad, respectively; extensor margin with 4–7 small proximal spines on P2–4; flexor margin with 8 or 9 slender movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.4–0.5 that of propodi; flexor margin with 7 or 8 proximally diminishing teeth, terminal one prominent.

Epipods on P1.

Coloration. Base color of carapace, abdomen and pereopods light brown. Anterior half of abdomen sometimes with brown median longitudinal stripe. Most distal portion of pereiopod articles darker.

Remarks. Galathea caesariata is closely related to G. c r i n i t a n. sp. from New Caledonia and Chesterfield Islands and G. villosa n. sp. from Madagascar, Mozambique, and Vanuatu. These species are characterized by the presence of more than four epigastric spines and often with spinules on the hepatic and branchial regions, the lateral margin of the carapace has one small but distinct spine between the anterolateral spine and the anteriormost branchial marginal spine, and the antennular basal article with two distal spines, being obsolecent the distomesial spine. Galathea caesariata is easily distinguished from the other species by the relatively longer walking legs. For instance, the P2 propodus is more than eight times longer than broad in G. caesariata , whereas is clearly less than eight times in the other species.

The genetic divergence with G. v i l l o s a (no data for G. c r i n i t a) is 11.3% (16S rRNA) (no data for COI) ( Tab. 2 ).

Distribution. Papua New Guinea, Vanuatu and New Caledonia, 340– 600 m.

Figures

FIGURE 20. Galathea caesariata n. sp., holotype, male, 5.1 mm, Vanuatu (MNHN-IU- 2013 - 15938). 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 3, lateral view; H, right P 4, lateral view. Scale: A, E – H = 1 mm; B – D = 0.5 mm.

FIGURE 116. Dorsal view. A, Galathea boucheti n. sp., Madagascar, holotype, male 4.0 mm (MNHN-IU- 2013 - 8110). B, Galathea caesariata n. sp., Vanuatu, holotype, male 5.0 mm (MNHN-IU- 2013 - 15938). C, Galathea celiae n. sp., Red Sea, male 2.8 mm (UF 32860). D, Galathea consobrina De Man, 1902, Vanuatu, female 3.2 mm (MNHN-IU- 2013 - 8386). E, Galathea cymo n. sp., Vanuatu, ovigerous female 4.0 mm (MNHN-IU- 2013 - 13343). F, Galathea erythrina n. sp., Red Sea, holotype, female 1.3 mm (UF 36824). G, Galathea eulimene n. sp., Red Sea, Saudi Arabia, male 3.1 mm (UF 35961). H, Galathea galene n. sp., ovigerous female 5.4 mm (MNHN-IU- 2013 - 9878). I, Galathea gladiola n. sp., Vanuatu, holotype, female 4.5 mm (MNHN-IU- 2013 - 8436).