Galathea barbellata, 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 : 410-412

Galathea barbellata n. sp.

( Fig 1 )

HOLOTYPE. — New Caledonia. SMIB 4, stn DW55, 23°21.40’S, 168°04.50’E, 260 m, 9.III.1993, 1 ovig. ♀, 4.9 mm (MNHN-IU-2009-587). PARATYPES. — Vanuatu. MUSORSTOM 8, stn CP1086, 15°36’S, 167°16’E, 182-215 m, 5.X.1994, 1 ♂, 3.5 mm (MNHN-IU-2009-588).

New Caledonia. BERYX 11, stn CP44, 23°41’S, 168°01’E, 230-250 m, 20.X.1992, 1 ♀, 3.5 mm (MNHN- IU-2009-589).

SMIB 8, stn DW155, 24°45’S, 168°08’E, 257-262 m, 28.I.1993, 1 ovig. ♀, 3.6 mm (MNHN-IU-2009-590).

DISTRIBUTION. — Vanuatu and New Caledonia, in 182- 262 m.

ETYMOLOGY. — From the Latin “barba”, beard, in reference to the numerous setae on the body and appendages, “ellus” (diminutive suffix), and “tus” (adjective suffix denoting possession or fullness).

DESCRIPTION

Carapace, exclusive of rostrum, 1.2-1.3 times as long as broad; dorsal surface nearly horizontal from anterior to posterior; anterior and posterior cervical grooves distinct; epigastric and secondary ridges scale-like, interrupted ridge between the anteriormost branchial marginal spines directly behind the anterior cervical groove; mid-transverse ridge interrupted, preceded by distinct cervical groove, followed by three interrupted and three uninterrupted transverse ridges placed alternately; ridges setose and with some scattered long and thick plumose setae. Epigastric region with 9-11 small spines; two submedian protogastric spines, and one or two parahepatic spines on each side; two postcervical spines on each side and two pairs of cardiac spines placed side by side; sometimes one anterior branchial spine on each side. Lateral margins subparallel, with seven spines: two spines in front of and five strong spines behind anterior cervical groove; first anterolateral, well developed, distinctly posterior to level of lateral limit of orbit; second small, situated at midlength between anterolateral spine and anterior cervical groove, accompanying another small spine ventral to between first and second; two spines on anterior branchial region, and three spines on posterior branchial margin. Small outer orbital spine; infra-orbital margin with one or two denticles. Rostrum 2.0-2.5 times as long as broad, length 0.5-0.6 that of, breadth 0.2-0.3 that of carapace, dorsal surface nearly horizontal in lateral view, with small setiferous ridges; lateral margin with four sharp teeth.

Pterygostomian flap rugose with sparse setae, anteriorly rounded; some granules on upper margin near linea anomurica.

Sternal plastron 1.2 times as long as broad. Sternite 3 1.9 times as broad as long, anterior margin bilobated. Sternite 4 slightly wider than following sternite, with one or two small spines on each side of anterior margin, 4 times longer and 3.5 times broader than preceding sternite, 0.6 as long as broad; surface with few short transverse ridges bearing long setae. Following sternites smooth on surface; sternites 6 and 7 with setose anterolateral margin.

Abdominal somites 2-4 each with three uninterrupted transverse ridges on tergite; somites 5 and 6 each with two ridges, both uninterrupted on somite 5 and both medially interrupted on somite 6. Telson 0.8 as long as broad, incompletely subdivided.Two pairs of male gonopods.

Ocular peduncles 1.6-1.9 times longer than broad; eyestalk (other than cornea) with some short fine setae on dorsal striae; cornea as broad as peduncle.

Basal article of antennular peduncle with three well-developed distal spines, distodorsal larger; additional small spine on each of ventromesial and lateral margins. Ultimate article with a few short setae not in tuft on distodorsal margin.

Article 1 of antennal peduncle with depressed ventral distomesial process not reaching distal margin of article 2. Article 2 with distolateral spine smaller than distomesial, not reaching midlength of article 3. Articles 3 and 4 unarmed.

Mxp3 basis with four or five denticles on mesial ridge, distal-most distinct, remainder very small. Ischium with well-developed spine on extensor distal margin; crista dentata with 18 or 19 denticles. Merus subequal in length to ischium, with three spines on flexor margin, proximalmost larger than others; extensor margin with distal spine. Carpus spineless.

P1 3.1-3.7 (females), 3.8-3.9 (males) times postorbital carapace length, relatively slender, subcylindrical, with long stiff setae on striae of all articles, and some scattered long and thick plumose setae. Merus 1.1-1.5 times length of carapace, 1.6-2.1 times as long as carpus, with several rows of spines, dorsomesial row with strong spines. Carpus 0.8-0.9 length of palm, 2.5-2.9 (females), 2.2-2.7 (males) times longer than broad, dorsal surface with row of small spines; mesial surface with well-developed spines; and some small spines along lateral margin. Palm 3.0-3.6 (females), 3.2-3.5 (males) times longer than broad; small dorsal spines roughly in three rows: mesial, dorsal and lateral; lateral row not continued on to lateral margin of fixed finger. Fingers 0.8-0.9 as long as palm, distally spooned, prehensile edges close fitting with intermeshing teeth when closed; mesial margin of movable finger unarmed.

P2-4 relatively short, somewhat compressed, setose, sparsely with thick long plumose setae on all articles. Meri successively shorter posteriorly (P3 merus 0.8 length of P2 merus, P4 merus 0.8 length of P3 merus), equally broad on P2-4; P2 merus 0.7 carapace length, 3.9 times as long as broad, 1.3 times longer than P2 propodus; P3 merus 3.4 times as long as broad, 1.0 times length of P3 propodus; P4 merus 3.5 times as long as broad, 0.9 length of P4 propodus. Dorsal margins with row of 6 or 7 proximally diminishing spines on P2-4; dorsolateral surface unarmed on P2-3, with 3 small spines on P4; ventrolateral margins ending in strong terminal spine proximally followed by smaller spine; ventromesial margin with small terminal spine on P2 only. Carpi each with 4-5 spines on extensor margin on P2-4, distal-most larger; dorsolateral surface with row of 2-4 small spines or acute granules paralleling extensor row; flexor distal margins with very small distal spine. Propodi subequal in length on P2-4, each 4.6-5.3 times as long as broad; extensor margin with 3-4 proximal spines on P2-4; flexor margin with seven or eight spines, terminal one paired with another smaller spine mesial to it. Dactyli subequal in length, 0.6 length of propodi, ending in incurved, strong, sharp spine; flexor margin with four or five successively diminishing teeth, terminal tooth prominent; each tooth with seta-like movable spine.

Epipods present on P1, absent on P2-3.

REMARKS Galathea barbellata n. sp. belongs to the group of species having an interrupted ridge between the anteriormost branchial marginal spines directly behind the anterior cervical groove, the rostrum with four lateral spines, the carapace lateral margin with a small spine between the anterolateral spine and the anteriormost branchial marginal spine, and the gastric striae not scale-like. The new species is closely related to G. robusta from Madagascar. Both species have submedian protogastric spines, parahepatic, and postcervical spines on each side, and two pairs of cardiac spines placed side by side. The new species is easily distinguished from G. robusta by the following differences ( Table 1): – the antennular basal article has three large spines and one additional small ventromesial spine in the new species, whereas this article has two spines in G. robusta ;

– the epigastric region bears more numerous spines in the new species than in G. robusta . Furthermore, the lateral protogastric and median mesogastric spines are absent in the new species, whereas these spines are present in G. robusta ;

– the anterior margin of sternite 4 bears one or two small spines on each side in the new species, whereas this margin is unarmed in G. robusta .

Figures

FIG. 1. — Galathea barbellata n. sp., holotype ovig. ♀, 4.9 mm (MNHN-IU-2009-587):A, carapace and abdomen,dorsal view;B, sternal plastron; C, cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp3, lateral view; E, right P1, dorsal view; F, right P2, lateral view; G, right P3, lateral view; H, right P4, lateral view.Scale bars: A, B, F, G, H, 1 mm; C, D, 0.5 mm; E, 2 mm.