Galathea minutiae, 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 : 198-200

Galathea minutiae n.sp.

( Fig. 71 )

Material examined. Holotype: New Caledonia. CALSUB, Stn 18, 22°46'S, 167°20'E, 301–700 m, 0 9 March 1989: F 2.0 mm (MNHN-IU-2013-8355).

Etymology. From the Latin, minutus, small, in referente to the small size of the species.

Description. Carapace: as long as broad; transverse ridges with dense short setae, and some scattered long plumose setae; cervical groove distinct, laterally bifurcated. Gastric region with 6 transverse ridges: 1 epigastric ridge with 2 spines, medially interrupted; 2 protogastric ridges, anterior uninterrupted and with 1 parahepatic spine on each side, posterior ridge short; 1 mesogastric ridge uninterrupted but not extending laterally to anteriormost of branchial marginal spines; 2 metagastric ridges, anterior uninterrupted, posterior short. Hepatic region with 1 small spine. Anterior branchial region with distinct ridges. Mid-transverse ridge uninterrupted, preceded by shallow cervical groove, followed by 5 ridges. Lateral margins well convex medially, with 7 spines: 2 spines in front of, and 5 spines behind, anterior cervical groove; first anterolateral, well-developed, at same level of lateral limit of orbit, second, small, at midlength between anterolateral spine and anteriormost spine of branchial margin, with small spine ventral to between first and second; 2 spines on anterior branchial region, last small, and 3 spines on posterior branchial margin, last small. Minute spine on lateral limit of orbit; infraorbital margin with strong spine. Rostrum 1.8 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 numerous short unirramous setae; lateral margin with 4 shallowly incised teeth.

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

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

Abdomen: Somites 2–4 each with 2 uninterrupted transverse ridges on tergite; somites 5 and 6 each with uninterrupted anterior ridge and 1 posterior medially interrupted ridge.

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

Antennule: Article 1 with 3 well-developed distal spines, distodorsal larger, distomesial spine clearly smaller than others; additional small spine on lateral margin. Ultimate article without setae on distodorsal margin.

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

Mxp3: Ischium with flexor and extensor margins ending in blunt angle; crista dentata with 16 denticles. Merus as long as ischium; flexor margin with 3 spines, proximal stronger than others; extensor margin unarmed.

P1: 4.0 times carapace length, with numerous setiferous scales, and some scattered long setae. Merus 1.8 times carapace length, 2.0 times as long as carpus, with some spines, dorsomesial and distal spines stronger than others. Carpus 0.9 length of palm, 3.5 times as long as broad; dorsal surface with some small spines; mesial margin with row of spines, distal slightly stronger than others. Palm 4 times longer than broad, lateral and mesial margins subparallel; small spines arranged roughly in dorsal, dorsolateral and dorsomesial rows. Fingers 0.8 times palm length, unarmed; each finger distally with two rows of teeth, spooned.

P2–4: long and slender, with some setose striae and sparse long plumose setae. P2 2.3 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P3 merus, P4 merus 0.7 length of P3 merus); P2 merus as long as carapace, 6 times as long as broad, 1.3 times longer than P2 propodus. Extensor margin with row of 6 or 7 proximally diminishing spines on P2–3, 1 distal spine on P4; ventral margins distally ending in strong spine, lateral sides unarmed. Carpi with 4–6 spines on extensor margin on P2–3, 4 on P4; lateral surface with 3 or 4 acute granules sub-paralleling extensor margin; flexor distal margin acute. Propodi 5.8–6.3 times as long as broad; extensor margin with 3 or 4 minute proximal spines; flexor margin with 5 or 6 movable spines. Dactyli distally ending in well-curved strong spine, length 0.6–0.7 that of propodi; flexor margin with 5 or 6 proximally diminishing teeth, terminal one prominent.

Epipods absent on pereiopods.

Remarks. Galathea minutiae n. sp. resembles G. consobrina De Man, 1902 . The new species is easily differenciated from G. consobrina by having the lateral rostral teeth shallowly incised and the P2–4 meri elongate. The P2 merus is more than 5 times longer than broad in G. minutiae , being less than 5 times longer than broad in G. consobrina . Furthermore, the rostral teeth are deeply incised in G. consobrina , being shallowly incised in G. minutiae .

The new species is also close to G. longimanoides Johnson, 1970 (see under Remarks of this species). No genetic data are available for G. minutiae .

Distribution. New Caledonia, 301– 700 m.

Figures

FIGURE 71. Galathea minutiae n. sp., holotype, female, 2.0 mm, New Caledonia (MNHN-IU- 2013 - 8355). 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 3, lateral view. Scale: A, F, G = 1 mm; E = 2 mm; B – D = 0.5 mm.