Petalosarsia suluensis, 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 : 22-25

Petalosarsia suluensis sp. nov.

( Figs. 16. 17 )

Material examined. Holotype juvenile female, 2.59 mm (NSMT-Cr 22086), 10°36.48ˏN, 121°31.56ˏE – 10°35.74ˏN, 121°30.98ˏE, 362–372 m (KH-02-4, St. SA2), 8 December 2002. Paratypes; 1 juvenile female, 2.49 mm (NSMT-Cr 22087), same locality and date as holotype female (KH-02-4, St. SA2); 1 adult male, 4.09 mm (NSMT-Cr 22088), 07°58.38ˏN, 118°16.27ˏE – 07°57.48ˏN, 118°16.68ˏE, 367–368 m (KH-02-4, St. S1-C), 23 November, 2002.

Description. Juvenile female ( Fig. 16 ). Body weakly calcified, surface of integument smooth. Carapace length 0.29 times total body length, without carina or ridges, dorsal surface arched; anterolateral angle with a tooth ( Fig. 16 C); frontal margin between the teeth on anterolateral angle 0.67 times greatest width of carapace ( Fig. 16 B); pseudorostrum 0.19 times as length of carapace. inferior margin smooth, without tooth. Width of eye lobe 0.19 times width of carapace. Pereon 0.52 times carapace. Pleon 0.55 times total body length ( Fig. 16 A).

Antenna 1 ( Fig. 16 D) 1st article of peduncle 1.55 times combined length of 2nd and 3rd; 2nd article not open distally; subequal to 3rd; main flagellum of 3 articles, with 2 aesthetascs; 1st article 1.45 times combined length of 2nd and 3rd. Maxilliped 3 ( Fig. 16 E) basis 1.2 times length of distal articles together.

Pereopod 1 ( Fig. 16 F) basis 1.1 times combined length of ischium and carpus, without plumose seta on inner margin; carpus length 1.9 times width, 2.9 times dactylus length, 0 77 times basis length. Pereopod 2 ( Fig. 16 G), basis 0.8 times length of distal articles together. Pereopod 3 ( Fig. 16 H) basis 1.8 times length of remaining distal articles; exopod absent. Pereopod 4 ( Fig. 16 I) basis 1.1 times length of remaining distal articles; exopod absent. Pereopod 5 ( Fig. 16 J) basis 0.6 times length of remaining distal articles.

Uropod ( Fig. 16 K), peduncle 1.21 times pleonite 6 length, 0.60 times exopod length, 0.50 times endopod length; exopod 0.82 times endopod length, with 3 setae on inner margin, 2 terminal setae; endopod with 3 spiniform setae on inner margin and with 2 terminal setae. Telson semicircular, 0.58 times length of pleonite 6.

Adult male ( Fig. 17 ). Carapace length 0.31 times total body length, length 1.75 times greatest width and 2.21 times depth; dorsolateral carina absent, anterolateral angle without tooth and antennal notch. Width of frontal margin about 0.8 times greatest width of carapace; pseudorostrum 0.18 times length of carapace; width of eye lobe 0.135 times width of carapace. Pereon 0.54 times carapace. Pleon 0.53 times total body length, with 2 pairs of pleopods.

Antenna 1 ( Fig. 17 C), 1st article of peduncle 1.3 times combined length of 2nd and 3rd; main flagellum of 5 articles; 1st article with 12 aesthetascs; accessory flagellum of 3 articles, shorter than proximal 3 articles of main flagellum combined. Antenna 2 ( Fig. 17 D), peduncle with plumose seta; flagellum of 22 articles, exceeding posterior end of telson . Maxilliped 3 ( Fig. 17 E) basis 1.3 times remaining distal articles, with 6 plumose setae on inner margin and inner distal corner. Basis of maxilliped 3 and pereopods 1–4 strongly constructed, with well developed exopods.

Pereopod 1( Fig. 17 F) basis 1.4 times combined length of ischium and carpus; carpus length 1.8 times width, 2.55 times dactylus length, 0.63 times basis length. Pereopod 2 ( Fig. 17 G) basis 1.1 times length of remaining distal articles, dactylus slightly longer than carpus. Pereopods 3, 4 ( Fig. 17 H, I) basis broad at base, 2.2 and 1.5 times length of remaining distal articles respectively. Pereopod 5 ( Fig. 17 J) thin, basis 0.75 times length of remaining distal articles. Pleopod 1 ( Fig. 17 K), outer and inner rami partially fused; outer ramus with 2 long, almost naked setae on ventral side and 2 robust, short plumose setae (arrow heads) on dorsal side; inner ramus with 5 plumose setae; inner margin of peduncle with 4 plumose setae on inner margin and plumose seta on outer margin. Pleopod 2 normal for the genus ( Fig. 17 L).

Uropod ( Fig. 17 M) peduncle 1.48 times pleonite 6 length, 0.61 times exopod length, 0.53 times endopod length; exopod 0.86 times endopod length, with 3 short setae on inner margin, 2 minute setae on outer margin, 2 terminal setae; endopod with 6 spiniform setae on inner margin and 2 terminal setae. Telson ( Fig. 17 M) triangular, 0.56 times pleonite 6.

Etymology. The species name refers to the locality, the Sulu Sea, that the specimens were collected.

Distribution. Western Sulu Sea, Philippine, 362– 372 m.

Remarks. This species resembles Petalosarsia longirostris Jones, 1973 and P. jonesi sp. nov. in having the carapace without dorsolateral carina. However, these specimens are distinguishable from the latter two species by combination of (1) carapace not compressed laterally, its inferior margin is not serrated, (2) pereonite 3–5 without blunt or sharp spines on dorsal crest, (3) main flagellum 1st article of antenna 1 much less than twice the length of remaining two articles, (4) inner distal corner of carpus of pereopod 1 nearly rectangular, (5) uropod peduncle in female specimen short, slightly longer than pleonite 6, and (6) antenna 2 of adult male with long flagellum exceeding posterior end of abdomen.

Figures

FIGURE 16. Petalosarsia suluensis sp. nov., juvenile female. A, lateral view; B, anterior portion of body, from above; C, anterolateral angle of carapace; D, antenna 1; E, maxilliped 3; F – J, pereopods 1 – 5; K, uropod with pleonite 6.

FIGURE 17. Petalosarsia suluensis sp. nov., adult 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.