Petalosarsia longicauda, Akiyama, Tadashi & Gerken, Sarah, 2012

Akiyama, Tadashi & Gerken, Sarah, 2012, The Cumacean (Crustacea: Peracarida) Genus Petalosarsia (Pseudocumatidae) from the Pacific Ocean, Zootaxa 3320, pp. 1-35 : 25-27

Petalosarsia longicauda sp. nov.

( Fig. 18 )

Material examined. Holotype subadult male, 4.25 mm (NSMT-Cr 22089), 06°18.41ˏN, 119°10.82ˏ– 06°18.65ˏN, 119°11.34ˏE, 1131–1392 m (KH-00-1, St. B2-5), 23 February 2000.

Description. Subadult male ( Fig. 18 ). Carapace length 0.28 times total body length ( Fig. 18 A), length 1.78 times greatest width and 1.89 times depth; anterior portion with lateral carina, with 4 teeth; very weak dorsolateral carina with 4 teeth present on anterior portion ( Fig. 18 B); dorsal surface arched; transverse ridge near hind margin absent; frontal margin between lateral carina 0.73 times greatest width of carapace; pseudorostrum 0.20 times length of carapace; width of eye lobe 0.18 times width of carapace. Pereon 0.51 times carapace. Pleon 0.58 times total body length, with 2 pairs of pleopods ( Fig. 18 A).

Antenna 1 ( Fig. 18 C) 1st article of peduncle 1.3 times combined length of 2nd and 3rd; main flagellum of 5 articles; accessory flagellum of 3 articles, 0.27 times main flagellum. Antenna 2 ( Fig. 18 D) peduncle with plumose seta; flagellum of 21 articles. Maxilliped 3 ( Fig. 18 E) basis 1.25 times remaining distal articles, without seta on inner margin.

Pereopod 1 ( Fig. 18 F) basis 1.3 times combined length of ischium and carpus; carpus length 1.9 times its width, 3.1 times dactylus length, 0.66 times basis length. Pereopod 2 ( Fig. 18 G) basis 0.94 times remaining distal articles. Pereopods 3, 4 ( Fig. 18 H, I) basis broad at base, 2.05 and 1.4 times length of remaining distal articles respectively. Pereopod 5 ( Fig. 18 J) basis 0.95 times length of remaining distal articles. Pleopod 1 ( Fig. 18 K) undeveloped, with a few short setae on tip of rami. Pleopod 2 with minute rami ( Fig. 18 L).

Uropod ( Fig. 18 M) peduncle 1.13 times pleonite 6 length, 0.53 times exopod length,0.45 times endopod length; exopod 0.84 times endopod length, with 7 short setae on inner margin, 2 short setae on outer margin, terminal setae lost during collection; endopod with 4 spiniform setae on inner margin, 2 terminal setae. Telson ( Fig. 18 M) semicircular, 0.41 times pleonite 6.

Etymology. The species name refers to the elongate pleon.

Distribution. South of the Sulu Sea, Philippine, 1131–1392 m.

Remarks. This species is separated from other members of the genus by the combination of (1) dorsal surface of carapace arched, anterior portion of lateral margin with very weak ridge with four teeth, (2) pleon rather long, 0.58 times total body length, (3) inner margin of basis of maxilliped 3 and pereopods without plumose setae, (4) uropod exopod with a row of several thin setae on inner margin.

Figures

FIGURE 18. Petalosarsia longicauda sp. nov., subadult male. A, lateral view; B, anterior portion of body, from above; C, antenna 1; D, antenna 2; E, maxilliped 3; F – J, pereopods 1 – 5; K, L, pleopods 1, 2; M, uropod with pleonite 6.