Fennerogalathea ensifera, 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 ensifera n. sp.

( Figs 5 , 6 E, F)

Material examined. Holotype: Fiji, MUSORSTORM 10, Stn CP 1323, 17°16.10'S, 177°45.75'E, 143–173 m, 7 August 1998, M 6.1 mm (MNHN-IU-2013-17407).

Paratypes: Fiji. MUSORSTOM 10: Stn CP 1320, 17°16.78'S, 177°53.57'E, 290–300 m, 6 August 1998: 4 M 6.3–8.8 mm, 1 ov. F 7.2 mm (MNHN-IU-2013-17397).— Stn CP 1323, 17°16.10'S, 177°45.75'E, 143–173 m, 7 August 1998: 3 M 4.1–7.1 mm, 3 F 4.8–5.6 mm (MNHN-IU-2013-17409).— Stn CP 1322, 17°17.10'S, 177°47.92'E, 210–282 m 7 August 1998: 2 M 5.2–6.8 mm (MNHN-IU-2013-17408).— Stn CP 1322, 17°17.10'S, 177°47.92'E, 210–282 m, 7 August 1998: 1 ov F 4.9 mm (MNHN-IU-2013-17396).— Stn DW 1329, 17°19.33'S, 177°47.36'E, 102–106 m, 8 August 1998: 1 ov F 4.8 mm (MNHN-IU-2013-17405).— Stn CP 1351, 17°31.14'S, 178°39.96'E, 292–311 m, 11 August 1998: 1 M 4.7 mm (MNHN-IU-2013-17398).— Stn CP 1351, 17°31.14'S, 178°39.96'E, 292–311 m, 11 August 1998: 1 ov F 4.6 mm (MNHN-IU-2013-17399).— Stn CP 1349, 17°31.07'S, 178°38.79'E, 244–252 m, 11 August 1998: 1 F 5.1 mm (MNHN-IU-2013-17406).— Stn CP 1364, 18°11.9'S, 178°34.5'E, 80–86 m, 15 August 1998: 1 ov F 5.5 mm (in gorgonians) (MNHN-IU-2013-13919).

Fiji. BORDAU 1. Stn CP 1402, 16°38.33'S, 179°36.40'E, 260–279 m, 25 February 1999: 1 F, 3.9 mm (MNHN- IU-2013-17401).— Stn CP 1404, 16°39.87'S, 179°35.70'E, 180 m, 25 February 1999: 1 F 5.3 mm (MNHN-IU- 2013-17410).— Stn CP 1404, 16°39.87'S, 179°35.70'E, 180 m, 25 February 1999: 1 F 3.7 mm (MNHN-IU-2013- 17400).

Etymology. From de Latin ensis, sword in reference to the long rostrum.

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 or 5 spines; median row protogastric composed of 7 or 8 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 2 small spines; one postcervical spine on each side. Front margin oblique; limit of orbit ending in small spine, one small spine between orbit spine and first anterolateral spine; one spine on the ventral orbital margin. Lateral margins of carapace nearly parallel medially and slightly convex; carapace margin armed with 6 or 7 small spines: 2 spines in front and 4–5 spines behind anterior cervical groove; first spine anterolateral, small, poorly-developed at level of epigastric row of spines; 2 spines on anterior branchial margin and 2–3 spines on posterior branchial margin; posterior transverse ridge straight and spineless. Rostrum triangular, flattish dorsally, narrow and elongate, 2.2–2.5 times longer than broad, 0.5 times of as long as remaining carapace; lateral margin armed with 4–5 incised teeth; distance between distalmost lateral incisions 0.25 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: Somite 2 with 2 uninterrupted transverse ridges on tergite, somites 3–4 smooth, with anterior uninterrupted ridge without 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, 0.6–0.7 times shorter than rostrum. Ocular peduncles 1.7–2.1 times longer than broad, maximum corneal diameter 0.8 rostrum width.

Antennule: Article 1 with well-developed distolateral and distodorsal spines on, distodorsal overreaching distolateral, distomesial margin usually unarmed or with one minute spine.

Antenna: Article 1 hardly visible from dorsal view, with 1 small, distinct distomesial spine. Article 2 slightly wider and longer than article 3 with distolateral and distomesial spines subequal in size. Article 3 with 1 small distomesial 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 subequal spines on flexor margin; extensor margin unarmed. Carpus spineless.

P1: 4.3–4.4 (males), 5.7–6.0 (females) times postorbital carapace length, with some scattered short and long setae on dorsal surface and along lateral and mesial margins of all articles. Merus 1.6 longer than carapace, 1.5–1.6 times as long as carpus, with numerous spines, stronger spines along mesial and dorsodistal margins. Carpus 0.9– 1.0 times as long as palm, 3.4–3.6 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 2.4–2.5 (males), 4.5–4.8 (females) times longer than broad, lateral and mesial margins subparallel; spines arranged in longitudinal rows; dorsolateral row continued onto whole lateral margin of fixed finger. Fingers as long as or slightly longer than palm, each finger distally with 2 rows of teeth, spooned; movable finger with row of some spines in proximal half of mesial margin, otherwise unarmed.

P2–4: Slender, moderately setose, sparsely with long plumose setae on all articles. P2 2.7 times carapace length. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 1.1 of carapace length, 10 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 7.5 times as long as broad, 1.2 times length of P3 propodus; P4 merus 6.0 times as long as broad, 0.9 length of P4 propodus; extensor margins each with row of 10–12 spines in P2–3, and with 6 small spines in P4; lateral surfaces unarmed in P2–3, 1 or 2 minute spines in P4; flexor margins each with strong terminal spine in P2–4, 5 or 6 additional spines in P2–3, 1 or 2 in P4; ventromesial margins with 1 or 2 spines in P2. Carpi each with 6 or 7 spines on extensor margin of P2–4; lateral surfaces each all with row of 2 or 3 small spines paralleling extensor row; flexor margins unarmed or with minute spine. P2–4 propodi 8.5–9.5 times as long as broad; extensor margins each with 5–7 small proximal spines in P2–4; flexor margins nearly straight, each with 2 pairs of terminal spines preceded by 7 or 8 slender movable spines. Dactyli subequal in length, 0.4–0.5 length of propodi, ending in incurved, strong, sharp spine; flexor margins each with prominent triangular terminal tooth preceded by row of 8 or 9 teeth.

Distribution. Fiji, between 102 and 311 m.

Remarks. Fennerogalathea ensifera n. sp. is clearly differentiated from its congeners by the shape of the rostrum, which is narrower and more elongate than in the other species. The differences are as follows.

The rostrum is more than twice longer than broad, and clearly exceeding the corneae in F. ensifera n. sp., whereas it is at most twice longer than broad, not reaching or slightly exceeding the corneae in the other species.

The distance between the distalmost lateral incisions of the rostrum is 0.25 the distance between the proximalmost lateral incisions in F. ensifera n. sp., whereas this ratio is 0.4 in the other species.

The lateral spines of the carapace are small in F. ensifera n. sp., whereas these spines are always well developed in the other species.

The minimum molecular divergence observed between F. ensifera n. sp. and F. cultrata n. sp. was 9.43% and 0.70% for the COI and 16S, respectively.

Figures

FIGURE 5. Fennerogalathea ensifera n. sp., holotype, male 6.1 mm (MNHN- IU- 2013 - 17407), Fiji. 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, right P 2, lateral view. H, right P 3, lateral view. I, right P 4, lateral view. Scale: A, E – I = 1 mm; B – D = 2 mm.

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.