Tropicoecetes carinata, Just, Jean, 2012

Just, Jean, 2012, Siphonoecetini Just, 1983 (Crustacea, Amphipoda, Ischyroceridae) 10: Belkginoecetes gen. nov., Tropicoecetes gen. nov. and Rhinoecetes Just, 1983 from north-eastern and northern Australian shallow water, with eight new species, Zootaxa 3528, pp. 1-28 : 21-23

Tropicoecetes carinata sp. nov.

Figures 14–15

Type fixation. Holotype, male, here designated.

Etymology. The epithet alludes to the anterolateral keel (carina) on the basis of gnathopod 2.

Material examined. Holotype, 3, 2.8 mm, Danger Point, Port Bremer, Cobourg Peninsula, Northern Territory, Australia, 11°07.2'S, 132°20.4'E 4 m, sandy beach, A.J. Bruce, 1 May 1982, stn CP-35, MAGNT Cr 0 0 1727.

Paratypes. Same data as holotype, MAGNT Cr004034 (1 damaged Ƥ).

Description (holotype, 3). Head, from front margin, as long as pereonites 1 and 2 combined along dorsal midline. Pseudorostrum acutely pointed, straight in lateral view; in dorsal view reaching beyond apices of eye lobes with its entire length. Eye lobes tapering to broadly rounded apex in lateral view, rounded rectangular in dorsal view, lower anterior margin with single simple seta.

Antenna 1 approximately as long as head and pereonites 1–6 combined; flagellum of 6+ articles, approximately as long as peduncle articles 2 and 3 and 1/3 of 1 combined. Antenna 2 [broken after article 3] ventral projection of peduncle article 2 base width 0.85 greatest length, broadly rounded distally, with fringe of long setae laterally and apically.

Mouthparts, mandible palp article 1 with a few setae in distal half and 3 long apical setae. Maxilla 2 inner plate with row of terminal setae, a single long seta mid-medially, and naked space in between ( Fig. 15 Fmx2).

Gnathopod 1 propodus length 3.4 width, with 2 midposterior robust setae pointing forward nearly parallel to posterior margin. Gnathopod 2 basis with anterolateral sinuous flange terminating in triangular proximal projection; propodus length 2.0 greatest width. Pereopods 3–4 basis with a few setae on posterior margin, [anterior margin not observed], a single long seta on lateral surface; merus with single short midanterior seta, posterior margin with groups of a few unequally long setae. Pereopods 5–6 basis with a couple of setae in distal half of anterior margin, posterior margin apparently without setae; ischium to dactylus with a few tiny setae only.

Uropod 1 peduncle with 3 dorsolateral simple setae; outer ramus 4 times longer than wide, approximately 0.5 length of peduncle, dorsal margin with 2 robust setae, with single dorsal simple seta; inner ramus slender, 0.8 length of outer ramus. Uropod 3 distolaterally with 4 long simple setae, mediodistally with 2 short simple setae. Telson width 1.4 times length, apex barely convex.

Female. The single paratypic female is heavily damaged, but it is similar to the male in the following points: gnathopod 1 propodus posterior robust setae strongly forward pointing; gnathopod 2 basis with identical anterolateral flange; urosome as in male.

Size. Largest 3, 2.8 mm; the single Ƥnot measurable.

Colour and biology. Not known.

Distribution. Danger Point, Port Bremer, Cobourg Peninsula, Northern Territory, Australia. 4 m.

Figures

FIGURE 14. Tropicoecetes carinata gen. et sp. nov. Holotype, 3, except F, paratype, Ƥ. c dv and c lv, head dorsal and lateral view; us, urosome; vp, ventral projection of article 2 of antenna 2. Habitus scale: 1 mm.

FIGURE 15. Tropicoecetes carinata gen. et sp. nov. Holotype, 3, except F, paratype, Ƥ. gp 1 and gp 2, gnathopods 1 and 2; md plp, mandible palp; mx 1 and mx 2, maxilla 1 and 2; p 4 and p 6, pereopods 4 and 6.