Paramunida achernar, Cabezas, 2010

Cabezas, P. E., 2010, Taxonomic revision of the genus Paramunida Baba, 1988 (Crustacea: Decapoda: Galatheidae): a morphological and molecular approach, Zootaxa 2712, pp. 1-60 : 9-10

Paramunida achernar n. sp.

( Figs. 1, 12A)

Paramunida cretata Macpherson 2004: 283 ( Tonga, 371–497 m) (not P. cretata Macpherson, 1996 ).

Material examined. Holotype: Tonga. BORDAU 2 . Stn CP 1643, 21°04.54'S, 175°22.50'W, 22 June 2000, 487 m: ov. F 9.7 mm (MNHN-Ga7468).

Paratypes: Tonga. BORDAU 2 . Stn CP 1510, 21°04.65’S, 175°22.52’W, 31 May 2000, 461– 497 m: 3 M 9.0– 10.7 mm, 3 F 8.9–9.8 mm (MNHN-Ga7469). — Stn 1545, 21º17.46’S, 175º17.18’W, 05 June 2000, 444– 447 m: 2 M 10.4–11.2 mm. — Stn 1586, 18º34.20’S, 173º54.93’W, 13 June 2000, 440– 487 m: 1 ov. F 11.5 mm. — Stn 1596, 19º06.46’S, 174º18.19’W, 14 June 2000, 371– 437 m: 2 ov. F 9.1–9.5 mm. — Stn CP 1643, 21°04.54'S, 175°22.50'W, 22 June 2000, 487 m: ov. F 10.2 mm .

Etymology. The name achernar refers to one of the stars of the southern hemisphere (constellation of Eridanus); used as a noun in apposition.

Description. Carapace: As long as broad. Spinules on gastric and hepatic regions forming groups arising from scale-like striae and with few short uniramous setae. Epigastric region with 2 spines, each behind supraocular spine; with median row of spinules behind rostral spine. Mesogastric region with median row of 3 spines, first thicker than others. Anterior branch of cervical groove with short setae. Cervical groove distinct. Cardiac and anterior branchial regions slightly circumscribed. Cardiac region with a median row of 3 welldeveloped spines, first thicker than others. Each branchial region with row of spines near cardiac region. Frontal margin slightly concave. Lateral margins convex, with some spines and iridescent setae on anterior half. Anterolateral spine well developed, exceeding or reaching sinus between rostral and supraocular spines. Rostrum spiniform, larger than supraocular spines, with thin dorsal longitudinal carina; margin between rostral and supraocular spines straight or slightly concave ( Figs. 1A, B).

Sternum: Thoracic sternites 4–6 with few arcuate striae; sternite 7 smooth ( Fig. 1C).

Abdomen: Abdominal somites 2–3 each with 4 well-developed spines on anterior ridge, posterior ridge with 2 median spines. Abdominal somite 4 with 4 spines on anterior ridge; posterior ridge with distinct single median spine ( Fig. 1A).

Eyes: Maximum corneal diameter more than one-third distance between bases of anterolateral spines.

Antennule: Segment 1 slightly exceeding corneae, with distomesial spine small and slightly shorter than distolateral; twice longer than wide and with fringe of long setae along lateral margin; distal slender portion about half as long as proximal inflated portion ( Fig. 1D).

Antenna: Anterior prolongation of segment 1 slightly overreaching antennular segment 1 by about onefourth of its length. Segment 2 about twice length of segment 3 and twice longer than wide, ventral surface with scales; distomesial spine spiniform, not exceeding antennal peduncle, reaching midlength of anterior prolongation of segment 1, distolateral spine not reaching end of segment 3; segment 3 nearly 1.5 times longer than wide and unarmed ( Fig. 1D).

Maxilliped 3: Ischium about twice length of merus measured along dorsal margin, distoventrally bearing long spine; merus with well developed median spine on flexor margin; extensor margin unarmed ( Fig. 1E).

Pereopop 1: Long and slender, squamate, between 4.8–4.9 times carapace length; carpus about as long as palm, 5.9–6.5 times longer than height; palm 1.2–1.3 times finger length. Base of carpus without bundle of setae ( Fig. 1F).

Pereopods 2–4: Long and slender, with numerous scales on lateral sides of meri, carpi and propodi; scales with short setae. P2 3.1–3.2 times carapace length, merus 1.5–2.0 times longer than carapace, about 12 times as long as high, 4.5 times as long as carpus and 1.5–1.7 times as long as propodus; propodus 11–14 times as long as high, 1.7 times dactylus length. Merus with well developed spines on dorsal border, increasing in size distally, ventral margin with few spines and one well-developed distal spine; row of small spines along ventrolateral margin. Carpus with some small dorsal spines, distal spine on dorsal and ventral margin. Propodus with small movable ventral spines. Dactylus compressed, slightly curved, with longitudinal carinae along mesial and lateral sides, ventral border unarmed. End of P2 carpus reaching end of P1 merus. P3 with similar spination and segment proportions as P2; merus slightly shorter than P2 merus; propodus and dactylus as long as those of P2. P4 as long as P2; merus 1.5–2.2 times carapace length; propodus and dactylus as long as those of P3; merocarpal articulation slightly exceeding end of anterior prolongation of segment 1 of antennal peduncle ( Figs. 1G–I).

Remarks. The new species is morphologically very close to P. antares n. sp. from New Caledonia and P. cretata from the Wallis Islands, Waterwitch Bank and Fiji (see Remarks for those species).

Distribution. Tonga, between 371 and 497 m.

ped 3, lateral view. F, left P1, dorsal view. G, right P2, lateral view. H, right P3, lateral view. I, right P4, lateral view. Scales: A–C = 1 mm; D–E = 0.5 mm; F–I = 2 mm.