Paramunida tenera, 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 : 47-53

Paramunida tenera n. sp.

( Figs. 11, 15F)

Paramunida setigera Macpherson 1993: 464 (in part, specimens from New Caledonia); 2004: 289 ( Fiji, 210−527 m) (not P. setigera Baba, 1988 ).

Material examined. Holotype: New Caledonia. BATHUS 4. Stn CP 946, 20°33' S, 164°58' E, 10 August 1944, 386– 430 m: M 8.0 mm (MNHN-Ga7496).

Paratypes: Fiji. MUSORSTOM 10. Stn CP 1349, 17°31.07'’S, 178°38,79'E, 11 August 1998, 244– 252 m: 6 M 7.4–9.3 mm, 5 ov. F 7.8–8.5 mm, 6 F 5.7–9.2 mm (MNHN-Ga7497) .

Vanuatu. BOA 0. Stn CP 2326,15º39.83’S, 167º01.9’E, 18 November 2004, 260– 313 m: 1 M 9.3–9.4 mm, 3 ov. F 7.7–8.9 mm (MNHN-Ga7498). — Stn CP 2327, 15º39.48’S, 167º01.46’E, 18 November 2004, 287– 440 m: 18 M 8.5–11.7 mm, 15 ov. F 8.2–10.5 mm (MNHN-Ga7499) (one incompete male, P. aff. setigera , could be a different species). SANTO. Stn AT 1, 15°33.8'S, 167°19.5'E, 14 September 2006, 167– 367 m: 1 F 8.2 mm (MNHN-Ga7500). — Stn AT 2, 15°32.8'S, 167°16.5'E, 14 September 2006, 160– 175 m: 1 ov. F 7.5 mm (MNHN-Ga7501). — Stn AT 19, 15°40.8'S, 167°00.5'E, 21 September 2006, 503– 600 m: 1 ov. F 8.0 mm (MNHN-Ga7502). — Stn AT 27, 15°22.4'S, 167°15.4'E, 23 September 2006, 341– 347 m: 1 M 9.6 mm (MNHN-Ga7503) .

New Caledonia. BATHUS 4. Stn CP 946, 20°33' S, 164°58' E, 10 August 1944, 386– 430 m: 4 M 7.9–12.2 mm, 1 ov. F 9.5 mm, 1 F 10.2 mm (MNHN-Ga7504) .

Etymology. From the Latin, tener, delicate, in reference to the thin and long walking legs.

Description. Carapace: Slightly longer than broad. Spinules on gastric and hepatic regions usually not forming groups, lacking scaly striae and with few short uniramous setae. Epigastric region with 2 spines, each behind supraocular spine; withouth median row of spines behind rostral spine. Mesogastric region without row of median spines. Cervical groove distinct. Cardiac and anterior branchial regions slightly circumscribed.

Cardiac region with a median row of 3 well-developed spines, first thicker than others. Each branchial region with 1 or 2 moderately-sized spines near cardiac region. Frontal margin slightly concave. Lateral margins convex, with some spines and iridescent setae on anterior half. Anterolateral spine well developed, reaching sinus between rostral and supraocular spines. Rostrum spine short, triangular, with thin dorsal longitudinal carina;

supraocular spines as long as rostral spine; margin between rostral and supraocular spines straight or slightly concave ( Figs. 11A, B).

Sternum: Thoracic sternite 4 with few arcuate striae; sternites 5–7 with few and small striae on lateral sides ( Fig. 11C).

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. 11A).

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

Antennule: Segment 1 reaching or slightly exceeding corneae, with distomesial spine small and shorter than distolateral; twice longer than wide and with fringe of long setae along lateral margin; lateral margin with distal slender portion about half as long as proximal inflated portion ( Fig. 11D).

Antenna: Anterior prolongation of segment 1 clearly overreaching antennular segment 1 by about onethird of its length. Segment 2 about 1.5 times length of segment 3 and about twice longer (measured along lateral margin) than wide (measured at midlength of segment), ventral surface with scales; distomesial spine mucronated, overreaching antennal peduncle, overreaching midlength of anterior prolongation of segment 1,

distolateral spine reaching midlength of segment 3; segment 3 nearly twice longer than wide and unarmed

( Fig. 11D).

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. 11E).

Pereopod 1: Long and slender, squamate, 6.7–7.1 times carapace length; carpus 0.8 times palm length, and 9.1–11.0 times longer than height; palm 1.4–1.6 times fingers length. Base of carpus without bundle of setae ( Fig. 11F).

Pereopods 2–4: Long and slender, with numerous scales on lateral sides of meri, carpi and propodi; scales with short setae. P2 4.1–4.8 times carapace length, merus 1.8–2.1 times longer than carapace, 17–20 times as long as high, 4.2–4.6 times as long as carpus and 1.7–1.8 times as long as propodus; propodus 13–15 times as long as high, and 1.2–1.5 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, well developed distal spine on dorsal and ventral margins. 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 clearly not reaching end of P1 merus. P3 with similar spination and segment proportions as P2; merus as long as P2 merus; propodus and dactylus slightly longer than those of P2. P4 slightly longer than P2; merus 2.0–2.2 times carapace length; propodus and dactylus slightly longer than those of P3; merocarpal articulation clearly exceeding end of anterior prolongation of segment 1 of antennal peduncle ( Figs. 11G–I).

Remarks. The new species is closely related to P.setigera from the Philippines and Indonesia. These species can be differentiated by the following characters:

— The thoracic sternites have numerous striae in P. setigera , whereas there are few striae on sternites 4–7 on the new species.

— A bundle of setae is present at the base of the P1 carpus in P. setigera , whereas it is absent in the new species.

The genetic divergences between P.tenera and P. setigera were 4.85% (16S rRNA) and 9.15% (ND1).

One incomplete male from BOA 0, Stn CP2327 ( P. aff. setigera ), showed a significant genetic divergence with the other specimens, 4.71% (16S rRNA) and 8.90% (ND1), suggesting the existence of an additional cryptic species. Unfortunately, the incomplete specimen prevents a complete description, and additional material is necessary in order to determine its taxonomic status.

Distribution. Fiji, Vanuatu and New Caledonia, between 160 and 600 m. abdomen, dorsal view. B, carapace, lateral view. C, sternum. D, left antennule and antenna, ventral view. E, right maxilliped 3, lateral view. F, right P1 merus and carpus, dorsal view. G, right P1 palm and fingers, dorsal view. H, right P2, lateral view. I, right P3, lateral view. J, right P4, lateral view. Scales: A–C = 1 mm; D–E = 0.5 mm; F–I = 2 mm.

female 10.6 mm. D, P. spica , holotype, ovigerous female 7.1 mm. E, P. stichas, HALIPRO 1, Stn Stn CP877, female 8.9 mm. F, P. tenera , holotype, male 8.0 mm. G, P. thalie, EBISCO, Stn CP2632 , male 8.8 mm. H, P. tricarinata, MUSORSTOM 2, Stn CP35, ovigerous female 9.8 mm.