First record of the genus Ruffojassa Vader & Myers , 1996 ( Amphipoda , Corophiidea ) from Brazilian waters , with description of a new species ”

A new species, Ruffojassa petronioi sp. nov., is described from southern Brazilian coast. The new species was collected at 56 m depth at the coordinates 21o42’S / 40o15’W with a mini biological trawl aboard of R.V. Prof. W. Besnard. In this paper we recorded the genus for the first time from Brazilian waters.


Introduction
The genus Ruffojassa was erected by Vader and Myers (1996) being distinct of Parajassa Stebbing, 1899 mainly by the presence of an accessory flagellum, the shape of coxa 5 and the ornamentations of uropod 3.In that revision, all species of Parajassa, except for P. pelagica (Leach, 1814), have been transferred to the genus Ruffojassa, and a new species, R. festa Vader and Myers, 1996, was described.Up to date there are nine known species of Ruffojassa, including the new species described herein.This genus has a worldwide distribution and most of its species inhabit shallow waters, 0-130 m depth (Barnard and Karaman, 1991).Some species of Ruffojassa have been recorded in association with other invertebrates, such as hermit crabs, e.g.Strigopagurus strigimanus (White, 1847), Diacanthurus spinulimanus (Miers, 1876) and Paguristes barbatus (Ortmann, 1892) (Moore, Lowry (1997).The following abbreviations are used in the figures: Ep, epistome; Gn, gnathopod; HA, habitus; LL, lower lip; Md, mandible; Mx, maxilla; Mxp, maxilliped; P, pereopod; T, telson; Ur, uropod; m, male; f, female.
Description: Head shorter in length than the first two pereonites combined; lateral cephalic lobes very prominent, anteroventral margin deeply regressed, eye of moderate size, occupying the lateral lobes of the head.Antenna 1 shorter and more slender than antenna 2, bearing long setae on posterior margin, mainly on peduncular article 1 and 2, peduncular article 2 twice as long as article 1, peduncular article 3 0.8 X of peduncular article 2 length; flagellum 7-articulate.Antenna 2 peduncular article 5 1.3 X longer than article 4; flagellum 5-articulate, article 1 equal in length to others combined.Epistome strongly produced into an acute projection.Lower lip with large inner lobes.Mandible incisor 2-dentate, lacinia mobilis 3-dentate, 3 accessory spines present; palp elongate, article 2 1.2 X longer than article 3 with media and lateral setae, article 3 spatulate, with a row of long plumose setae.Maxilla 1 inner plate small, triangular and naked; outer plate with 7 serrate robust setae; palp 2-articulate, article 2 with 6 apical robust setae and 4 sub-apical setae.Maxilla 2 outer plate broader than inner plate, both apically setose.Maxilliped inner plate rectangular, shorter than half of the outer plate, with 3 apical robust setae and 6 apical pinnate setae; inner plate reaching over half way along article 2 of palp, with 5 robust setae along medial margin and 4 pinnate setae and 2 plumose setae on distal margin; palp 4-articulate, article 2 2.5 X longer than article 3, both articles with a row of setae on inner margin, article 4 with apical setae.
Gnathopod  ovoid, 1.9 X longer than wide, anterior margin with simple and plumose setae, posterior margin longer than palm, with long plumose setae, densely setose medially; palm acute, with a bifid process near hinge of dactylus and another small process near palmar corner separated by a weakly excavated area; palmar corner defined by a subacute spine; dactylus robust, curved, inner margin smooth and almost reaching end of palm.Pereopods 3 and 4 similar in shape and ornamentation, bases about 1.7 X longer than wide; merus expanded with an anteroventral rounded lobe reaching of middle of carpus.Pereopod 5 basis with a row of plumose setae on anterior margin; propodus with 2 robust setae on anteromedial margin and 1 apical robust seta; dactylus short with 1 apical robust setae.Pereopods 6 and 7 missing.Epimera 1-3 posteroventral margin rounded.Uropod 1 peduncle 1.3 X longer than rami, with row of robust setae along both margins, outer margin with 3 plumose setae, apical margin with 1 large interramal spine; inner ramus with 1 apical robust seta; outer ramus naked.Uropod 2 peduncle 2 X longer than rami, with 3 robust setae on outer margin and 4 long simple setae on inner margin, apical margin with 1 short spine; outer ramus with 2 robust setae on lateral margin and 1 apical robust seta; inner ramus with 2 apical robust setae.Uropod 3 short, peduncle 1.5 X longer than inner ramus, outer margin with 6 long simple setae, inner margin with 3 apical robust seta, apical margin with 3 robust setae; inner ramus 1.3 X longer than outer ramus, both with apical robust setae.Telson subrectangular, with one lateral simple seta on each side.
Female: 5.5 mm.Similar to the male except for the gnathopods which are shorter and more slender.Gnathopod 1 propodus with 3 robust setae along posterior margin, palmar angle not defined.Gnathopod 2 less setose than male, palm defined by 1 short robust seta and.
Remarks: Ruffojassa petronioi sp.nov.resembles R. andromedae sharing with that species the oblique palm defined by a spine of the male gnathopod 2 and long setae on anterior margin of basis of pereopod 5.However, the new species differs of R. andromedae in the very prominent lateral cephalic lobes, dactylus of male gnathopod 1 as long as palm, male gnathopod 2 palm acute with a bifid process near hinge of dactylus and another small process near palmar corner separated by a poorly excavated area and palmar corner defined by a subacute spine, peduncles of uropods 1 and 2 with few setae along outer margin and telson with only simple setae.Ruffojassa festa shares with the new species the very prominent lateral cephalic lobes, long setae on the basis of pereopod 5 and the presence of few long setae on outer margin of peduncles of uropods 1 and 2, but the former can be distinguished from it by the palm of both gnathopods of male defined by a process or a spine, the longer interramal spine on uropod 1, a lack of constriction on outer ramus of uropod 2 and ornamentation of telson.
Depth range: The specimens studied herein were collected at 56 m depth.