Fennerogalathea chani, Rodriguez-Flores, Paula C., Machordom, Annie & Macpherson, Enrique, 2017

Rodriguez-Flores, Paula C., Machordom, Annie & Macpherson, Enrique, 2017, Three new species of squat lobsters of the genus Fennerogalathea Baba, 1988 (Decapoda: Galatheidae) from the Pacific Ocean, Zootaxa 4276 (1) : -

Fennerogalathea chani n. sp.

( Figs 2 , 3 , 6 A, B)

Material examined. Holotype: Papua New Guinea, New Ireland, KAVIENG CP4457, 2°33'S, 150°41'E, 133–178 m, 2 September 2014, M 3.6 mm (MNHN-IU-2014-13380).

Paratype: Papua New Guinea, PAPUA NIUGINI Stn PP 3, 0.5°14'S, 145°49'E, 120–180 m, 30 December 2012 (in gorgonians): 1 M 3.4 mm (MNHN-IU-2013-503).

Etymology. Name for our colleague and friend Tin-Yam Chan, for his contribution of the knowledge of crustacean biology.

Description. Carapace: 1.3 times longer than broad, dorsally armed with scattered spines and setae and some short transverse ridges; cervical groove distinct. Gastric region indistinctly defined and armed with 3 transverse rows of small spines: anterior row epigastric composed of 4 spines; median row protogastric composed of 6 spines, and posterior row mesogastric composed of 2 spines on a medially interrupted ridge. Cardiac region with 2 spines distinctly defined. Anterior branchial regions each armed with 1 or 2 small spines; 1 or 2 postcervical spines on each side. Front margin moderately oblique; limit of orbit ending in minute spine, margin between orbit spine and first anterolateral spine unarmed; 1 or 2 spines on ventral orbital margin. Lateral margins of carapace nearly parallel medially and slightly convex; carapace margin armed with 6 or 7 well-developed spines: 2 spines in front and 4 or 5 spines behind anterior cervical groove; first spine anterolateral, subequal to second spine, at level of epigastric spines; 1 or 2 spines on anterior branchial margin and 3 spines on posterior branchial margin; posterior transverse ridge spineless. Rostrum triangular, flattish dorsally, narrow and elongate, 1.6–2.0 times longer than broad, 0.4 times of as long as remaining carapace; each lateral margin armed with 3 basal and 1–2 distal tiny distal spines; distance between distalmost lateral incisions 0.3 distance between proximalmost lateral incisions.

Sternum: Plastron longer than broad, lateral limits divergent anteriorly. Third thoracic sternite nearly quadrangular, sternite 4 contiguous to entire posterior margin of sternite 3, and wider than sternite 5.

Abdomen: Somites 2–3 with 2 uninterrupted transverse ridges on tergite, somite 4 smooth, with anterior uninterrupted ridge with median tuft of setae; somites 5 and 6 smooth; posteromedian margin on somite 6 straight. Males with G1 and G2.

Eyes: Eyes stalk subcylindrical, narrow and elongate, 0.7 times shorter than rostrum. Ocular peduncles 1.7–2.0 times longer than broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with well-developed distolateral and distodorsal spines, distodorsal slightly overreaching distolateral, distomesial margin with 1 or 2 minute spines.

Antenna: Article 1 hardly visible from dorsal view, without distinct distomesial spine. Article 2 slightly wider and longer than article 3, with short distolateral and distomesial spines subequal in size. Article 3 with 1 small distomesial and minute distolateral spine. Article 4 unarmed.

Mxp3: Ischium with well-developed distal spine on flexor margin; extensor margin unarmed; crista dentata with 25 or 26 denticles. Merus subequal in length to ischium, with 3 or 4 acute granules (holotype) or spines (paratype) on flexor margin, proximal longer than others; extensor margin unarmed. Carpus spineless along extensor margin.

P1: 5.0 times postorbital carapace length, with some scattered short and long setae on dorsal surface and along lateral and mesial margins of all articles. Merus 2.1 longer than carapace, 1.9 times as long as carpus, with numerous spines, stronger spines along mesial and dorsodistal margins. Carpus 0.8 times as long as palm, 4.1 times longer than broad, lateral and mesial margins subparallel, dorsal surface with small spines; mesial surface with some strong spines; row of spines along lateral margin. Palm 3.2 times longer than broad, lateral and mesial margins subparallel; spines arranged in dorsolateral and dorsomesial rows. Fingers as long as palm, each finger with a few minute proximal spines, distally with 2 rows of teeth, spooned.

P2–4: Slender, moderately setose, sparsely with long plumose setae on all articles. P2 2.9 times carapace length. Meri successively shorter posteriorly (P3 merus 0.7 length of P2 merus, P4 merus 0.9 length of P3 merus); P2 merus 1.1 of carapace length, 8.0–8.5 times as long as broad, 1.2 times longer than P2 propodus; P3 merus 4.5 times as long as broad, as long as P3 propodus; P4 merus 5.0 times as long as broad, as long as P4 propodus; extensor margins each with row of 5–7 spines in P2–4; lateral surfaces unarmed in P2–3, 2–3 minute spines in P4; flexor margins each with strong terminal spine in P2–4, 3–5 additional spines in P2–3, unarmed in P4; ventromesial margins each with terminal spine in P2–4. Carpi each with 6 or 7 spines on extensor margin of P2–4; lateral surfaces each all with row of 2 or 3 small acute granules paralleling extensor row; flexor margins unarmed or with minute spine. P2–4 propodi 7.5 (P4)–9.5 (P2) times as long as broad; extensor margins each with 2–3 small proximal spines in P2–4; flexor margins nearly straight, each with 2 pair of terminal spines preceded by 8–9 slender movable spines. Dactyli subequal in length, 0.5 length of propodi, ending in incurved, strong, sharp spine; flexor margins each with prominent triangular terminal tooth preceded by row of 6 teeth.

Distribution. Papua New Guinea, at 120– 180 m.

Coloration. Base color translucent whitish with scattered red spots on carapace and abdomen; spines on rostrum and carapace whitish; epigastric and cardiac regions pale orange; abdominal somites 2–5 each with median orange stripe, median long setae reddish. Ocular peduncles with lateral margin orange, some scattered minute red spots. P1 with orange and whitish bands, with numerous scattered red spots. P2–4 translucent whitish, with some scattered minute red spots.

Remarks. The new species is closely related to Fennerogalathea chacei Baba, 1988 , from the Philippines, Taiwan and Bali Sea ( Baba 1988, 2005; Baba et al. 2009). Both species have the frontal margin between the lateral orbital spine and the first anterolateral spine of carapace unarmed. However , morphologically they can be easily distinguished by the number of spines along the lateral margins of the rostrum, two in F. chacei and three in F. chani n. sp. The molecular divergence between these species is 7.60% ( COI).

Figures

FIGURE 2. Fennerogalathea chani n. sp., holotype, male 3.6 mm (MNHN IU- 2014 - 13380), Papua New Guinea. A, carapace and abdomen, dorsal view. B, sternal plastron. C, cephalic region, showing antennular and antennal peduncles, ventral view. D, right Mxp 3, lateral view. E, right P 1, merus and carpus, dorsal view. F, palm of right P 1, dorsal view. G, left P 2, lateral view. H, left P 3, lateral view. I, left P 4, lateral view. Scale: A, B, E – H, I = 1 mm; C, D = 2 mm.

FIGURE 3. Fennerogalathea chani n. sp., paratype, male 3.4 mm (MNHN-IU- 2013 - 503), Papua New Guinea. Dorsal view.

FIGURE 6. Rostrum and right anterior part of cephalothorax, dorsal view, showing eyes and orbit. Fennerogalathea chani n. sp.: A, male 3.4 mm (MNHN-IU- 2013 - 503); B, male 3.6 mm (MNHN IU- 2014 - 13380). Fennerogalathea cultrata n. sp.: C, ovigerous female 4.0 mm (MNHN-IU- 2013 - 17419); D, male 3.2 mm (MNHN-IU- 2013 - 17412). Fennerogalathea ensifera n. sp.: E, ovigerous female 4.9 mm (MNHN-IU- 2013 - 17396); F, male 4.7 mm (MNHN-IU- 2013 - 17398). Scale = 1 mm.