Galathea sanctae, 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 : 422-426

Galathea sanctae n. sp.

( Figs 5 ; 6B )

HOLOTYPE. — Vanuatu. SANTO 2006 , stn AT27, 15°22.4’S, 167°15.4’E, 341-347 m, 23.IX.2006, 1ovig. ♀, 5.5 mm (MNHN-IU-2009-609).

PARATYPES. — Vanuatu. MUSORSTOM 8, stn CP1092, 15°10’S, 167°12’E, 314-321 m, 6.X.1994, 1 ovig. ♀, 6.8 mm (MNHN-IU-2009-610). — Stn CP1118, 15°08’S, 166°53’E, 191-248 m, 9.X.1994, 1 ♂, 6.7 mm (MNHN-IU-2009-611). — Stn CP1120, 15°07’S, 166°53’E, 282-321 m, 9.X.1994, 1♂, 6.8 mm, 2 ovig. ♀♀, 5.1-6.2 mm (MNHN-IU-2009-612).

BOA 0, stn CP2326, 15°39.83’S, 167°01.9’E, 260-313 m, 18.XI.2004, 1 ♂, 5.0 mm (MNHN-IU-2009-613). SANTO 2006, stn AT9, 15°41.5’S, 167°01.3’E, 481 m, 17.IX.2006, 2 ♂♂, 5.7-5.8 mm, 1 ovig. ♀, 5.5 mm (MNHN-IU-2009-614). — Stn AT27, 15°22.4’S, 167°15.4’E, 341-347 m, 23.IX.2006, 1 ovig. ♀, 5.1 mm, 1 ♀, 4.8 mm (MNHN-IU-2009-615). — Stn AT63, 15°39.6’S, 167°01.3’E, 290-334 m, 4.X.2006, 1 ♂, 6.3 mm, 1 ovig. ♀, 5.4 mm, 1 ♀, 5.2 mm (MNHN- IU-2009-616). New Caledonia. HALIPRO 1, stn CP852, 21°44’S, 166°36’E, 253-266 m, 19.III.1994, 1 ♂, 5.6 mm (MNHN-IU-2009-617). BATHUS 4, stn CP952, 20°34’S, 164°58’E, 270-316 m, 10.VIII.1994, 1 ♂, 3.7 mm (MNHN-IU-2009-618). — Stn CP955, 21°45’S, 166°37’E, 242-250 m, 11.VIII.1994, 1 ovig. ♀, 4.5 mm (MNHN-IU-2009-619).

DISTRIBUTION. — Vanuatu and New Caledonia, at 191- 481 m.

ETYMOLOGY. — From the Latin “sanctus” in reference to the type Locality (Espiritu Santo Island).

DESCRIPTION

Carapace, exclusive of rostrum, as long as broad; dorsal surface nearly horizontal from anterior to posterior. Cervical groove distinct, laterally bifurcated. Gastric region with nine setiferous ridges; first epigastric, with two or three submedian spines; second medially convex anteriorly; fourth scalelike; fifth laterally not continuous to anteriormost branchial marginal spine; sixth to eighth successively shorter posteriorly, uninterrupted; anterior branchial region with distinct ridges; mid-transverse ridge uninterrupted, preceded by cervical groove, usually followed by three interrupted and three uninterrupted transverse ridges placed alternately (five uninterrupted and one interrupted ridges in several specimens); some additional scattered scales among ridges; ridges with numerous simple setae. Lateral margins convex medially, with ten spines: three spines in front of and seven spines behind anterior cervical groove; first anterolateral, well developed, second and third very small, located between first and anterior cervical groove, accompanying another small spine ventral to between first and second; three well-developed spines on anterior branchial margin, and four spines on posterior branchial margin. Lateral orbital angle with small spine; infraorbital margin minutely denticulate. Rostrum 1.6-1.8 times as long as broad, length 0.5 postorbital carapace length and breadth 0.3 that of carapace; dorsal surface nearly horizontal in lateral view, with small setiferous ridges; lateral margin with five or six relatively small, shallowly incised teeth.

Pterygostomian flap spineless on surface, with sparse short setae, anterior margin bluntly angular.

Sternal plastron about as long as broad, lateral extremities gently divergent posteriorly. Sternite 3 twice as broad as long, with median depression bordering left and right lobes, anterior margin of each lobe convex, with minute dentitions. Sternite 4 2.0 times longer and 2.5 times broader than sternite 3, 0.4 as long as broad; surface with setiferous transverse ridges not reaching lateral margin. Following sternites smooth or with short ridge on each side.

Abdominal somites 2-3 each with four uninterrupted transverse ridges on tergite, anterior ridge more distinctly elevated than posterior ridge; somite 4 with uninterrupted anterior ridge and one medially interrupted posterior ridge; somites 5 and 6 with anterior ridge followed by one or two medially interrupted ridges, posteromedian margin nearly transversal with setiferous ridge, all these ridges with posteriorly directed fine setae. Telson 0.8 as long as broad, incompletely subdivided.Male gonopods on abdominal somites 1-2.

Ocular peduncles 1.3 times longer than broad; eyestalk (other than cornea) with lateral margin straight, dorsally with fine setae; cornea not dilated, as broad as peduncle.

Basal article of antennular peduncle with two spines; well-developed distodorsal and distolateral spines, distodorsal larger; distomesial spine obsolescent. Ultimate article with tuft of fine setae on distodorsal margin.

Antennal peduncle having article 1 hardly visible in dorsal view, with ventral distomesial spine not reaching distal margin of article 2. Article 2 with two distal spines, distolateral spine slightly larger than distomesial, not reaching midlength of article 3. Articles 3-4 unarmed.

Mxp3 basis with a few denticles on mesial ridge. Ischium with small spine on flexor distal margin; extensor margin with small but distinct distal spine; crista dentata with 17 or 18 denticles. Merus as long as ischium; flexor margin with two strong subequal spines, sometimes one additional small distal spine; extensor margin with distal spine. Carpus unarmed.

P1 3.1-3.4 (males), 2.7-3.1 (females) times postorbital carapace length, relatively slender, subcylindrical, with setose scales. Ischium with 1-3 ventrodistal spines. Merus 1.0-1.2 times as long as carapace, 2.0-2.1 times as long as carpus, with spines arranged roughly in rows, dorsomesial and ventromesial spines stronger, distal spines prominent. Carpus 0.6-0.7 length of palm, 2.0- 2.3 times as long as broad; dorsal surface with some small spines arranged roughly in rows; mesial margin with three or four spines (distal second largest). Palm 2.4-2.8 (females), 2.4-2.6 (males) times longer than broad, lateral and mesial margins subparallel; spines arranged roughly in dorsolateral and dorsomesial rows, some small spines scattered on dorsal side. Fingers 0.7-0.8 length of palm, distally spooned, prehensile edges close fitting with intermeshing teeth; opposable margins with blunt serration; mesial margin of movable finger unarmed.

P2-4 moderately slender, with setose striae. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.7 carapace length, 4.5 times as long as broad, 1.8 times longer than P2 propodus; P3 merus 3.9 times longer than broad, equally broad as P4 merus, 1.6 times longer than P3 propodus; P4 merus 3.3 times as long as broad, 1.3 length of P4 propodus. Dorsal margins with row of nine or ten proximally diminishing small spines on P2-3, distal spine only on P4; dorsolateral surface unarmed on P2-4; ventrolateral margin distally ending in strong spine followed proximally by several small spines. Carpi with four small spines on extensor margin on P2, one or two minute spines on P3-4; dorsolateral surface with acute granules sub-paralleling extensor margin on P2-4; flexor distal margin with small distal spine. Propodi subequal in length on P2- 4, each about 4 times as long as broad; extensor margin unarmed; flexor margin with six or seven slender movable spines on P2-4, terminal one paired with another smaller spine mesial to it. Dactyli subequal in length, distally ending in well-curved strong spine, 0.5 length of propodi; flexor margin with five successively diminishing teeth, terminal one prominent; each tooth with seta-like movable spine.

Epipods on P1, absent on P2-4.

Colouration

Carapace and abdominal somites 2-5 orange, anterior branchial regions reddish; one postcervical blue spot (directly behind bifurcation of cervical groove) on each side. Sixth abdominal somite, telson, and uropods whitish or traslucent. Pereopods orange; distal half of P1 fingers light orange; P2-4 propodi and dactyli with light and dark orange stripes.

REMARKS

The species is very closely related to G. multilineata , from Japan, East China Sea, Taiwan and the Philippines (e.g., Balss 1913; Baba 1988; Baba et al. 2009). Both species share an interrupted ridge between the anteriormost branchial marginal spines directly behind the anterior cervical groove, the rostrum with five lateral spines, and the carapace dorsal surface with numerous ridges. However, the new species is easily distinguished from G. multilineata by the following:

– two epigastric spines are distinct instead of absent;

– the secondary ridges on the carapace are less numerous;

– the lateral marginal teeth of the rostrum are more deeply incised;

– the hepatic lateral margin between the anterolateral spine and the end of anterior cervical groove bears two small but distinct spines, instead of being unarmed;

– the carapace dorsal surface bears two blue postcervical spots, which are absent in G. multilineata .

Figures

FIG. 5. — Galathea sanctae n. sp., holotype ovig. ♀, 5.5 mm (MNHN-IU-2009-609):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 (setae on carapace and appendages not illustrated). Scale bars: A, E, G, H, I, 2 mm; B, C, D, F, 1 mm.

FIG. 6.— A, Galathea raventosae n.sp.,holotype ♂, 4.5 mm,dorsal view;B, Galathea sanctae n. sp.,holotype ovig.♀, 5.5 mm,dorsal view.