Trachysalambria crosnieri, Chan, Tin-Yam, Cleva, Régis & Chu, Ka Hou, 2016

Chan, Tin-Yam, Cleva, Régis & Chu, Ka Hou, 2016, On the genus Trachysalambria Burkenroad, 1934 (Crustacea, Decapoda, Penaeidae), with descriptions of three new species, Zootaxa 4150 (3), pp. 201-254 : 221-223

Trachysalambria crosnieri sp. nov.

( Fig. 7 )

Type material. Holotype: South Australia, Gulf St. Vincent, F /V “ Rivoli Queen ”, 36–37 m, 0 5.06.1987, female cl 20.8 mm ( MNHN IU- 2014-6960 ) .

Paratypes: South Australia, Gulf St. Vincent, F /V “ Rivoli Queen ”, 36–37 m, 0 5.06.1987, 1 male cl 12.6 mm ( MNHN IU- 2014-6961 ), 1 male cl 12.4 mm, 4 females cl 17.2–23.2 mm ( MNHN IU- 2014-6962 ), 1 female cl 22.4 mm ( MNHN IU- 2014-6963 ) .

Other material examined. Australia. Queensland, Rockhampton, Keppel Bay , Middle Is., 9–36 m, 0 6.09.1967, 2 males cl 10.2 and 10.4 mm, 2 females cl 10.3 and 11.5 mm ( NMV J16271 ) . South Australia: Investigator Strait , 35°20’S, 136°45’E, 11.12.1985, 1 female cl 21.4 mm ( NMV J16270 ) ; Great Australian Bight , “ Southern Surveyor ”: 31°49.50’S, 130°45.19’E, 55 m, 13.05.2000, 3 females cl 17.3–20.6 mm ( NMV J52159 ) ; 31°49.54’S, 130°41.54’E, 14.05.2000, 1 male cl 13.1 mm, 1 female cl 14.0 mm (NMV J52160 ).

Description. Entire body densely pubescent. Rostrum with 6 or 7 (excluding epigastric tooth) teeth on dorsal border and with distal tooth somewhat far from tip; shape similar in both sexes and slightly curved upwards with ventral border more or less convex, tip slightly recurved downwards but directed horizontally and with ventral margin more or less straight, tips of rostral teeth aligned in a concave or straight configuration; more or less extending to tip of second segment of antennular peduncle (generally longer in females); postrostral carina blunt and only extending to about middle of carapace. Pereiopods I to III with well-developed epipods. Pereiopod I bearing small ischial spine. Pereiopod IV in females with coxa medially expanded as long setose plate. Pereiopod V more or less extending to middle of scaphocerite. Abdomen with dorsal carinae distinct and elevated on somites II to VI; that on somite II short but sometimes highly laminate; somite III with dorsal carina distinct over entire length though dorsal carina at anterior 1/3 of somite lower and sometimes nearly leveled; ridges on somites IV and V posteriorly incised and not terminating in spines. Telson with weak and blunt dorsolateral carinae, bearing 3 pairs of movable lateral spines. Male petasma with lateral margins of stem distinctly converging distally; distolateral lobes with ventral margins more or less straight, tips of dorsal and ventral flaps coinciding, forming sharp angle. Female thelycum with anterior plate semi-triangular, surface protruding as pair of large ball-like swellings in large individuals; anterior margin of posterior plate distinctly concave, with median cleft.

Coloration. Not known.

Distribution. Known with certainty only from Australia off Queensland and South Australia, at depths of 9– 55 m.

Remarks. The present new species is unique in the genus by large females having the coxae of the pereiopod IV medially expanded as long setose plates and the anterior plate of the thelycum strongly protruding as a pair of large ball-like swellings ( Fig. 7 G). Other species of Trachysalambria generally have the surface of the anterior plate of the thelycum flattened or somewhat sunken, and at most sometimes with low submedian swellings (e.g., in T. longipes , P. palaestinensis and T. aspera ). For the coxa of the pereiopod IV, it is never medially expanded in the other species of the genus. Dall (1957: 205) mentioned that his “ T. curvirostris ” material from Queensland in northeastern Australia has “Coxae of 4th legs with plate-like projection densely fringed with setae, ----”. However, no medially expanded plate is shown in the thelycum figure of Dall’s (1957: fig. 22E) material. It may be possible that Dall’s (1957) “ T. curvirostris ” material contains more than one species as some small specimens from Keppel Bay in Queensland examined here (NMV J16271 ) are tentatively identified to the present new species. These small specimens generally fit well the characteristics of T. crosnieri sp. nov. except the two females (cl only 10.3 and 11.5 mm) have the thelycum lacking ball-like swellings and the coxa of the pereiopod IV only slightly expanded medially. Other Australian reports of “ T. curvirostris ” (e.g., Schmitt 1926; Racek 1955; Racek & Dall 1965; Grey et al. 1983) seem not to refer to the present form. Re-examination of their material is necessary to determine the exact distribution of T. crosnieri sp. nov. in Australia.

Although the thelycum of T. crosnieri sp. nov. is unique in the genus, its petasma is of the general shape in Trachysalambria ( Fig. 7 D–F) and cannot be used as a distinguishing character. Nevertheless, T. crosnieri sp. nov. can also be separated from the other species of the genus in bearing fewer rostral teeth ( Fig. 7 A, C) and the anterior part of the abdominal somite III bearing distinct (though sometimes nearly leveled) dorsal carina ( Fig. 7 B). The fewer rostral teeth in T. crosnieri sp. nov. result in its rostrum being somewhat similar to that of T. curvirostris ( Fig. 15 A, B). On the other hand, the downward recurved tip of the rostrum in the present new species also resembles the rostrum of T. nansei ( Fig. 10 A, C–G). However, genetic analysis showed that T. crosnieri sp. nov. has very high sequence divergence to all the other species of Trachysalambria (> 21% in 12S rRNA gene though attempts in sequencing 16S rRNA gene failed; Table 2, Fig. 21).

Etymology. The species is named after Alain Crosnier, who first discovered this new species and entrusted us to complete his work on the revision of Trachysalambria .

Figures

FIGURE 7. Trachysalambria crosnieri sp. nov., Gulf St. Vincent, South Australia: A, B, G, holotype female cl 20.8 mm, (MNHN IU- 2014 - 6960); C, D – F, paratype male cl 12.6 mm (MNHN IU- 2014 - 6961). A, cephalothorax, lateral view; B, dorsal part of abdominal somites II to VI, lateral view; C, rostrum, lateral view, D – F, petasma, ventral, dorsal and upper views, respectively; G, thelycum, ventral view.

FIGURE 10. Trachysalambria nansei Sakaji & Hayashi, 2003: A, B, female cl 20.0 mm, Tosa Bay, Japan, (MNHN IU- 2014 - 6999); C, male cl 13.6 mm, Tosa Bay, Japan (MNHN IU- 2014 - 7139); D, female cl 19.3 mm, Australia, SO 682, stn 128 (MHNH IU- 2014 - 7020); E, female cl 19.0 mm, Tosa Bay, Japan (MNHN IU- 2014 - 7000); F, female cl 16.0 mm, Tosa Bay, Japan (MNHN IU- 2014 - 7000); G, female cl 16.0 mm, Australia, “ Soela ”, stn 130 (MNHN IU- 2014 - 7019). A, cephalothorax, lateral view; B, carapace, dorsal view; C – G, rostrum, lateral view.

FIGURE 15. Trachysalambria curvirostris (Stimpson, 1860), Taiwan: A, C, G, female cl 21.2 mm (MNHN IU- 2014 - 7093); B, D – F, male cl 16.4 mm (MNHN IU- 2014 - 7093): A, cephalothorax, lateral view; B, rostrum, lateral view; C, dorsal part of abdominal somites II to VI, lateral view; D – F, petasma, ventral, dorsal and upper views, respectively; G, thelycum, ventral view.