Bonassa brasiliensis, Senna, André R. & Serejo, Cristiana S., 2008

Senna, André R. & Serejo, Cristiana S., 2008, Amaryllididae and Lysianassidae (Amphipoda: Lysianassoidea) from off the central coast of Brazil (11 ºS – 22 ºS), with descriptions of three new species, Zootaxa 1718, pp. 45-68 : 51-55

Bonassa brasiliensis sp. nov.

( Figures 4–6 )

Type material. Holotype: REVIZEE Benthos Program, Central SCORE, N/R Astro Garoupa col.: female, 5.8 mm, 16º47'10"S – 37º41'10"W, 50 m, June 30, 2001, MNRJ 17760.

Paratype: REVIZEE Benthos Program, Central SCORE, N/R Astro Garoupa col.: one male, 16º47'10" S – 37º41'10" W, 50 m, June 30, 2001, MNRJ 19496.

Diagnosis. Antenna 2 subequal in length to the body. Upper lip rounded, more produced than epistome. Mandible, palp 3-articulate, article 2 slender and elongate, length 6X the width, with 6 distal setae, without setae in the ventral and dorsal margins, article 3, slightly falcate, length 4X the width, minutely setose, without setae on the dorsal margin, with two ventral setae and three apical setae. Gnathopod 1, basis slightly elongate, length 2.2X the width. Pereopod 3, merus, carpus and propodus, posterior margin with plumose setae in both sexes. Pereopod 6 with posterior margin concave. Telson with distal margin truncate.

Description. Holotype, female, 5.8 mm. Head and body without dorsal setae. Head deeper than long, lateral cephalic lobe large, narrow and rounded; rostrum absent; eye reniform. Antenna 1 small, 0.2X the body length; peduncle article 1, length 1.3X the width, ventrally setose; peduncle article 2, 0.4X article 1, with a tuft of setae distoventrally; primary flagellum 6-articulate; accessory flagellum 5-articulate, 0.75X the length of the primary flagellum. Antenna 2 subequal in length to the body.

Mouthparts forming a subquadrate bundle. Epistome and upper lip separate, epistome slightly produced and rounded; upper lip more produced than epistome, anterodorsal lobe rounded, anterior margin straight, with a setose anteroventral projection. Mandible, incisors symmetrical, distal margin slightly convex, minutely setose; accessory row of setae composed by three small stout setae; molar reduced and minutely setose; palp 3-articulate, article 1, length 3.5X the width, article 2 slender and elongate, length 6X the width, with 6 distal setae, without setae on the ventral and dorsal margins, article 3, slightly falcate, length 4X the width, minutely setose, without setae on the dorsal margin, with two ventral and three apical setae. Maxilla 1, outer plate wide, with 11 setal-teeth in an arrangement 7/ 4 in crown, large and robust ST1–7, ST1 1-cuspidate, ST2–3 2-cuspidate, ST4 3-cuspidate, ST5 4-cuspidate, ST6 8-cuspidate, ST7 4-cuspidate, STA-D, apically bifid, large and slender STA, small and robust STB-D; palp large, 2-articulate, with apical margin serrate and a stout seta present on the inner corner. Maxilla 2, outer plate narrow; inner plate enlarged, distomedial margin covered by plumose setae, plates subequal in length. Maxilliped, inner plate large, subrectangular, with three small nodular spines apically, medial margin setose; outer plate small, suboval, apical margin slightly serrate, subterminal setae present, inner margin with a medial seta; palp large, 4-articulate, article 2, length 2.6X the width, 2X the article 3, inner margin setose, article 3 long, length 2X the width, dactylus well developed, subterminal setae absent, nail absent.

Pereonites 1–7 dorsally smooth. Gnathopod 1 simple; coxa large, as long as coxa 2, anterior margin concave, anteroventral corner produced and rounded, posterior margin slightly convex, subterminal setae present; basis slightly elongate, length 2.2X the width, anterior margin smooth, with simple setae; ischium as long as broad; merus, posterior margin setose; carpus subrectangular, length 2X the width, anterodistal and posterodistal corners with tufts of setae; propodus elongate, length 2.2X the width, tapering distally, posterior margin, smooth, setose, slightly concave, palm absent; dactylus simple, subterminal spine absent. Gnathopod 2 subquelate; coxa large, subequal in size to coxa 3; basis elongate; ischium elongate, length 2.9X the width; merus subtriangular; carpus, length 3X the width, posterior margin lobate; propodus subrectangular, elongate, length 4X the width, palm obtuse, anterior margin smooth, posterodistal corner serrate; dactylus reaching the palmar corner, subterminal spine present.

Pereopod 3, coxa large; merus, carpus and propodus, posterior margin with plumose setae in both sexes; propodus with a distal stout seta on the posterior margin; dactylus elongate, thin, subterminal spine absent, nail absent. Oostegite elongate, with distal tubers, setae absent. Pereopod 4, coxa large and with posteroventral lobe, anterior and posterior margins subparallel, subterminal setae present; merus slightly expanded anteriorly, with a tuft of setae on the anterodistal corner; merus and carpus, posterior margin with plumose setae; merus, carpus and propodus, anterior margin minutely setose; propodus, posterior margin with simple setae and a distal stout seta; dactylus simple, subterminal spine absent, nail absent. Pereopod 5, coxa equilobate; basis expanded, posterior margin minutely serrate; merus expanded, with posterior margin rounded. Pereopod 6, coxa not lobate posteriorly; basis expanded, posteroventral lobe present, posterior margin concave, minutely serrate; merus expanded, with posterior margin rounded. Pereopod 7, coxa, anteroventral corner concave; basis expanded, posteroventral lobe present, posterior margin rounded, serrate, anterior margin straight.

Pleonites 1–3 and urosomites 1–3 dorsally smooth. Uropod 1, peduncle long, length 1.3X the rami, with nine dorsal stout setae, two dorsolateral stout setae and one apicolateral stout seta; rami subequal in length, outer ramus with one stout seta, inner ramus with six stout setae. Uropod 2, peduncle with four dorsal stout setae, one apicomedial stout seta and one apicolateral stout seta, rami subequal in length, outer ramus with five dorsal stout setae, inner ramus notched with one long and one short dorsal stout setae. Uropod 3, peduncle long, length 2.3X the width, dorsolateral projection absent, with four lateral stout setae, dorsal margin with plumose setae; rami paddle like, subequal in length, dorsal margin with long plumose setae, outer ramus 1- articulate, inner ramus, ventral margin with small simple setae. Telson, entire, longer than broad, length 1.7X the width, with one pair of dorsal stout setae, distal margin truncate, slightly concave, with one stout and one small slender seta on each lobe.

Remarks. The genus Bonassa was described by Barnard & Karaman (1991) based on a single male of Lysianassa bonairensis Stephensen, 1933 , collected in Bonaire, Caribbean Sea. Bonassa brasliensis sp. nov. is here described based on a female holotype and a male paratype, establishing that there is no sexual dimorphism in this genus. This information is added to the diagnosis of the genus, as until now the females were unknown for Bonassa . The Brazilian species presents the upper lip more produced than the epistome and the antenna 2 subequal in length to the body, while B. bonairensis presents the epistome and the upper lip subequally produced, and the antenna 2 with 0.65X the body length. Bonassa brasiliensis sp. nov. presents the basis of pereopod 6 with posterior margin concave, character found in other lysianassids, such as Concarnes concavus (Shoemaker, 1933) and Lysianopsis concavus Senna, 2007 , while B. bonairensis presents the basis of P7 with posterior margin rounded and slightly serrate.

Distribution. Bonassa brasiliensis sp. nov. was collected in a single station of southern Bahia State, at 50 m depth.

Etymology. The name brasiliensis refers to the endemism of this species from the Brazilian waters.

Figures

FIGURE 4. Bonassa brasiliensis sp. nov., female 5.8. mm, 16 º 47 ’ 10 ” S – 37 º 41 ’ 10 ”, 50 m, June 30, 2001, MNRJ 17760. Scale bars: 0.1 mm.

FIGURE 5. Bonassa brasiliensis sp. nov., female 5.8 mm, 16 º 47 ’ 10 ” S – 37 º 41 ’ 10 ”, 50 m, June 30, 2001, MNRJ 17760. Scale bars: 0.1 mm.

FIGURE 6. Bonassa brasiliensis sp. nov., female 5.8 mm, 16 º 47 ’ 10 ” S – 37 º 41 ’ 10 ”, 50 m, June 30, 2001, MNRJ 17760. Scale bars: 0.1 mm.