Galathea profunda, Macpherson, 2012

Macpherson, Enrique, 2012, New deep-sea squat lobsters of the genus Galathea Fabricius, 1793 (Decapoda, Galatheidae) from Vanuatu and New Caledonia, Zoosystema 34 (2), pp. 409-427 : 416-418

Galathea profunda n. sp.

( Fig. 3 )

HOLOTYPE. — Vanuatu. MUSORSTOM 8, stn DW1029, 17°53’S, 168°34’E, 324-360 m, 28.IX.1994, 1 ♂, 7.7 mm (MNHN-IU-2009-593).

PARATYPES. — Vanuatu. MUSORSTOM 8, stn CP1090, 15°08’S, 167°17’E, 470-502 m, 6.X.1994, 1 ♂, 6.1 mm (MNHN-IU-2009-594). New Caledonia. MUSORSTOM 4, stn CP239, 22°14.80’S, 167°15.70’E, 470-475 m, 2.X.1985, 1 ♂, 5.7 mm (MNHN-IU-2009-595). SMIB 3, stn DW1, 24°55.70’S, 168°21.80’E, 520 m, 20. V.1987, 1 ♀, 6.3 mm (MNHN-IU-2009-598). SMIB 5, stn DW101, 23°21.20’S, 168°04.90’E, 270 m, 14.IX.1989, 1 ovig. ♀, 4.9 mm (MNHN-IU-2009-597). BERYX 11, stn CH 49, 23°45.22’S, 168°17.06’E, 400- 460 m, 21.X.1992, 1 ♂, 6.1 mm (MNHN-IU-2009-596). BATHUS 3, stn CP812, 23°43’S, 168°15’E, 391-440 m, 28.XI.1993, 1 ovig. ♀, 7.0 mm (MNHN-IU-2009-599). — Stn CP833, 23°02’ S, 166°58’E, 441-444 m, 30.XI.1993, 1 ♀, 8.1 mm (MNHN-IU-2009-600). — Stn CP846, 23°02’S, 166°57’E, 500-514 m, 1.XII.1993, 1 ovig. ♀, 5.1 mm (MNHN-IU-2009-601).

BATHUS 4, stn CP912, 18°55’S, 163°07’E, 690-702 m, 5.VIII.1994, 1 ♂, 5.9 mm (MNHN-IU-2009-602).

NORFOLK 2, stn DW2041, 23°40.93’S, 168°01.29’E, 400 m, 23.X.2003, 1 ♂, 7.7 mm (MNHN-IU-2009-603). — Stn DW2156, 22°54.19’S, 167°15.13’E, 468-500 m, 5.XI.2003, 1 ovig. ♀, 7.1 mm (MNHN-IU-2009-604).

DISTRIBUTION. — Vanuatu and New Caledonia, between 270 and 702 m.

ETYMOLOGY. — From the Latin “profundus”, deep, in reference to the depth distribution of the species.

DESCRIPTION

Carapace 1.1 times as long as broad; no epigastric spines, only several acute granules present in epigastric region in a few specimens; small parahepatic spine on each side, sometimes absent; one strong median protogastric spine; gastric region with interrupted ridges; mid-transverse ridge uninterrupted, preceded by cervical groove, successively followed by three interrupted, one uninterrupted (interrupted in several specimens), and one interrupted transverse ridges; cardiac region with two spines placed side by side on elevated ridge preceded by depression or concavity; ridges with numerous simple setae, and some scattered thick and long plumose setae mostly on median gastric and cardiac regions.Lateral margin with two spines in front of and four spines behind distinct anterior cervical groove; first at anterolateral angle, slightly posterior to level of lateral limit of orbit, second very small, accompanying another small spine ventral to between first and second and, in several specimens, a minute spine at base of first spine; fourth spine strongest. Small outer orbital spine; infra-orbital margin with one spine. Rostrum 2.0-2.4 times as long as broad, length 0.6-0.8 that of, breadth 0.3-0.4 that of carapace; dorsal surface with small setiferous ridges; lateral margin with four deeply incised teeth.

Pterygostomian flap unarmed on surface, anteriorly rounded.

Sternal plastron slightly longer than broad, lateral extremities divergent posteriorly.Sternite 3 1.2 times longer than broad, anterior margin bilobated. Sternite 4 anteriorly narrow, medially concave, half as long as broad, length 3.5 times that of, breadth 5.4 times that of sternite 3; surface with some short transverse ridges on sternites 5-7.

Tergites of abdominal somites 2-3 with three transverse ridges; somites 4-6 each with two ridges, posterior one medially interrupted. Telson 0.9 as long as broad, incompletely subdivided. Two pairs of male gonopods.

Ocular peduncles 1.6 times longer than broad; anterior border of eyestalk not well extended anteriorly; cornea not dilated, as broad as peduncle.

Basal article of antennular peduncle with three spines, all well developed, distodorsal largest; ultimate article with a few short setae distally.

Article 1 of antennal peduncle with well-developed ventral distomesial spine exceeding article 2. Article 2 with distolateral spine slightly larger than distomesial spine, somewhat overreaching midlength of article 3. Article 3 unarmed.

Mxp3 ischium with very small spine on flexor distal margin, extensor margin also with distal spine; crista dentata with 21 or 22 denticles.Merus equally long as ischium, flexor margin with one strong spine at midlength and 1-3 small additional spines distal to it, extensor distal margin acutely angular or with distinct spine. Carpus unarmed.

P1 2.8-3.0 (females), 3.3-3.9 (males) times longer than carapace, relatively massive, with long stiff setae on ventral surface and along lateral and mesial margins, some scattered long and thick plumose setae.Ischium with two or three strong distal spines. Merus 1.2 as long as carapace, 1.6 times length of carpus; with some rows of spines, mesial spines strong. Carpus 1.7 times longer than broad; with some rows of spines, distomesial spine prominent. Palm 1.8-2.1 (males), 1.8-2.2 (females) times longer than broad, mesial and lateral spines small, lateral spines continued on to proximal half of fixed finger; carpus-palm length ratio 0.7. Fingers 0.6-0.8 (males), 0.6-0.7 (females) length of palm, distally spooned, prehensile edges close fitting with intermeshing teeth.

P2-4 somewhat compressed, setose, sparsely with long plumose setae. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.8 length of P3 merus); breadth subequal on P2-4; length-breadth ratio, 2.8 on P2, 2.7 on P3, 2.3 on P4; merus-propodus length ratio, 1.1 on P2, 0.9 on P3, 0.8 on P4; P2 merus 0.6 as long as carapace; dorsal margin with 6-7proximally diminishing spines on P2, 6-7 spines on P3, one or two distal spines (proximal one much smaller) on P4; ventromesial margin with strong terminal spine on P2-4. Carpi subequal, 0.6 length of propodi on P2-4; row of 4-5 spines on extensor margin. Propodi subequal on P2-4; length-breadth ratio, 4.5 on P2, 3.5 on P3, 4.0 on P4; flexor margin with six or seven spines on P2, eight or nine on P3, six or seven on P4, all movable. Dactylus 0.5-0.6 length of propodus on P2-4; flexor margin with six or seven proximally diminishing teeth, each with corneous spine.

Epipods present on P1, absent on P2-4.

REMARKS

The species is closely related to G. robusta Baba, 1990 from Madagascar in having an interrupted ridge between the anteriormost branchial marginal spines directly behind the anterior cervical groove, the rostrum with four deeply incised lateral teeth, the carapace lateral margin with a small spine between the anterolateral and anteriormost branchial marginal spines, and not scale-like gastric striae. However, G. robusta and the new species can be separated by the following ( Table 1):

– the new species has a strong median protogastric spine, whereas there are only two small metagastric spines in G. robusta . The epigastric region is unarmed in the new species, whereas there are some small spines and acute granules in G. robusta ;

– the branchial lateral margin of the carapace has four spines in the new species, instead of five spines in G. robusta ;

– the antennular basal article bears three welldeveloped spines in the new species, instead of only two in G. robusta ;

– the flexor margin of the Mxp3 merus bears three small spines distal to a prominent spine at the midlength in the new species, instead of three spines of moderate size (proximal and median subequal) in G. robusta ;

– the walking legs are broader in the new species than in G. robusta : P2 merus is less than 3 times longer than broad in G. profunda n. sp., whereas it is more than 4 times longer in G. robusta .

Figures

FIG. 3. — Galathea profunda n. sp., holotype ♂, 7.7 mm (MNHN-IU-2009-593): A, carapace and abdomen, dorsal view; B, anterior part of sternal plastron; C, cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp3, lateral view; E, right P1, dorsal view; F, distal part of P1 fingers, ventral view; G, right P2, lateral view; H, right P3, lateral view; I, right P4, lateral view. Scale bars: A, F, G, H, I, 2 mm; B, C, D, 1 mm; E, 0.5 mm.