Heteronida clivicola, Macpherson & Baba, 2006

Macpherson, Enrique & Baba, Keiji, 2006, New species and records of small galatheids (Crustacea, Decapoda, Galatheidae) from the Southwest and Central Pacific Ocean, Zoosystema 28 (2), pp. 443-456 : 451-454

Heteronida clivicola n. sp.

( Figs 5 ; 6 )

TYPE MATERIAL. — Holotype: French Polynesia. Austral Archipelago. BENTHAUS, stn DW 1897, 27°34.27’S,

144°26.68’W, 480-700 m, 8.XI.2002, ♂ 3.9 mm (MNHN-Ga 5307).

Paratypes: same station as for the holotype, 1 ♂ 3.4 mm (MNHN-Ga 5308). — Stn DW 2207, 22°26,60’S, 151°18,59’W, 323-580 m, 24.XI.2002, 2 ♂♂ 2.9 and 3.0 mm (MNHN-Ga 5309).

ETYMOLOGY. — The name refers to the roman goddess protecting the hills of Rome (Clivicola).

DISTRIBUTION. — French Polynesia (Austral Archipelago), 323- 700 m.

DESCRIPTION

Carapace slightly longer than broad, greatest breadth behind end of anterior cervical groove; dorsal surface finely granulated, posterior branchial region without distinct elevation. Gastric region with epigastric transverse ridge moderately distinct, epigastric spines absent or very small, papilla-like; strong median process rounded in profile, anterior extremity not produced, height less than 1/5 that of carapace (measured in lateral view between dorsal surface and linea anomurica). Cardiac region with somewhat elevated transverse ridge preceded by distinct cervical groove. Front margins strongly concave. Anterolateral spines strong, blunt, horizontal, directed straight forward, not reaching anterior margin of rostrum; small, blunt process in front of cervical groove. Lateral branchial margins somewhat convex, convergent behind end of anterior cervical groove, with a few small processes, anteriormost process rounded, produced laterally.

Rostrum much wider than long, horizontal, dorsal surface with median carina continued on to rostral spine and posteriorly to epigastric level; rostral spine small and blunt, barely exceeding supraocular spines.Lateral margins slightly convergent anteriorly, ending in small, blunt supraocular spines; anterior margins slightly concave.

Sternal plastron 3/4 as long as broad, sternites successively broader posteriorly. Sternite 3 having anterior margin transversal, surface depressed medially, width slightly less than half that of following sternite; anterior margin of sternite 4 contiguous with entire posterior margin of sternite 3, surface depressed medially.

Abdominal segments 2-4 each with strong humplike median process flanked by low process. Telson subdivided into nine platelets.

Cornea strongly dilated, without eyelashes; dorsal surface of peduncle granulate.

Antennular basal segment with two distal spines (distolateral larger than distomesial), and one very small lateral spine. Article 1 of antennal peduncle with stout distomesial process reaching end of article 2; article 2 moderately elongate, narrow, distomesial margin with small spine, distolateral margin strongly produced, nearly reaching end of article 3; articles 3 and 4 unarmed.

Mxp 3 ischium 1.5 times longer than merus when measured in mid-lateral border, with rounded distal process on each of flexor and extensor margins; merus with strong spine on extensor margin, flexor border with a few tubercles.

P1 2.7-2.9 times longer than carapace, granulate, subcylindrical; merus and carpus with small distomesial spine, palm 1.6 times longer than fingers.

P2-4 granulate. P2 reaching end of P1 carpus. Meri successively shorter posteriorly; extensor margin moderately cristate, with blunt distal spine; flexor margin tuberculate. Extensor margin of carpi tuberculate, with blunt distal spine. Propodi occasionally somewhat widened distally; flexor margin with movable distal spine; length 2/3 that of merus and slightly more than that of dactylus on P2, slightly less than that of dactylus on P3 and P4. Dactyli slender, somewhat curved; flexor margin with six to 10 spines, distal one rather close to tip;

extensor margin with plumose setae.

P5 fingers with simple, long, dense setae.

REMARKS

The new species is closely related to H. aspinirostris ( Khodkina, 1981) from Norfolk Ridge, New Caledonia, Loyalty Islands, Chesterfield Islands and Vanuatu, between 345 and 930 m. The two species are clearly distinguished by the following differences:

– each posterior branchial region of the carapace in H. aspinirostris has a distinct elevation, which is absent in the new species;

– the gastric process is prominently high and anteriorly produced in H. aspinirostris , whereas this process is low and rounded in the new species;

– and the distolateral margin of the article 2 of the antennal peduncle is strongly produced, nearly reaching the end of article 3 in the new species, whereas this margin is rounded in H. aspinirostris .

The new species is also clearly distinguished from H. barunae Baba & de Saint Laurent, 1996 , from Indonesia (205-425 m), by the presence of a carina in the midline of the rostrum, which is absent in H. barunae ; and the strong distolateral spine of antennal article 2, which is very small, barely reaching the mid-length of article 3, in H. barunae .

Figures

FIG. 5. — Heteronida clivicola n. sp., ♂ holotype, French Polynesia (MNHN-Ga 5307): A, carapace and abdomen, dorsal; B, same, lateral. Scale bar: 2 mm.

FIG. 6. — Heteronida clivicola n. sp., ♂ holotype, French Polynesia (MNHN-Ga 5307):A, left antennule, antenna, eye and anterior part of pterygostomian flap, ventral; B, sternal plastron; C, right Mxp 3, ischium and merus, lateral; D, right P1, dorsal; E, left P2, setae omitted, lateral; F, left P3, setae omitted, lateral; G, left P4, setae omitted, lateral; H, left P5. Scale bar: A-C, E-G, 1 mm; D, 2 mm; H, 0.5 mm.