Elasmopus karamani, Souza-Filho, Jesser F. & Senna, André R., 2009

Souza-Filho, Jesser F. & Senna, André R., 2009, Two new species of the genus Elasmopus Costa, 1853 (Amphipoda: Gammaridea: Maeridae) from off the Northeast Brazilian Coast, Zootaxa 2301, pp. 55-68 : 57-61

Elasmopus karamani sp. nov.

Figures 1–3

Material examined. Holotype. Male, 8.5 mm. REVIZEE Score NE, # 85A-III, gravel, 3°28’12”S- 35°03’36”W, 61.8 m, N. Oc. Antares, 04/VI/1998, MNRJ 21571.

Paratypes. REVIZEE Score NE, # 85A-III, gravel, 3°28’12”S- 35°03’36”W, 61.8 m, N. Oc. Antares, 04/ VI/1998, MNRJ 21577, 1 male. REVIZEE Score NE, # 85A-III, gravel, 3°28’12”S- 35°03’36”W, 61.8 m, N. Oc. Antares, 04/VI/1998, MNRJ 21578, 1 female (dissected and drew). REVIZEE Score NE, # 85A-III, gravel, 3°28’12”S- 35°03’36”W, 61.8 m, N. Oc. Antares, 04/VI/1998, MNRJ 21579, 66 males and 207 females. REVIZEE Score NE, # 85A-III, gravel, 3°28’12”S- 35°03’36”W, 61.8 m, N. Oc. Antares, 04/VI/ 1998, DOUFPE 14050, 52 males and 134 female. REVIZEE Score NE, # 40-III, gravel, 04°05’24”S- 37°25’48”W, 50 m, N. Oc. Antares col., 15/V/1998, DOUFPE 14049, 16 males and 1 female.

Etymology. The species is named in honor to Dr. Gordan S. Karaman for his great contribution in the amphipod taxonomy.

Diagnosis. Gnathopod 2 with propodous rectangular shaped, palm with a medial concave portion, a triangular process near hinge of dactylus and the palmar corner defined by two acute processes. Pereopod 5 and 6 basis posterior margin concave and serrate. Epimeron 3 produced in a sharp spine. Uropod 3 outer ramus about 2.4 X peduncle length, inner ramus subequal in length to the outer ramus. Telson cleft, each lobe notched with 2 apical robust setae.

Description. Based on holotype, male, 8.5 mm. Head with medium length eyes, rounded, with distinct ommatidia; lateral cephalic lobes broad, truncated, with anteroventral notch and slit, anteroventral corner rounded. Antenna 1 longer than antenna 2, about 0.7 X body length; peduncular article 1 0.82 X length of article 2, without robust setae along posterior margin, peduncular article 2 2 X length of article 3; flagellum shorter than peduncle with 23 articles; accessory flagellum with 3 articles. Antenna 2 densely setose, reaching the end of peduncle of antennae 1; peduncular article 4 subequal to article 5; flagellum with 11 articles. Mandible palp article 2 with setae along inner margin; article 3 strongly falcate, setose along concave margin, longer than article 2. Maxilla 1 inner plate with 2 apical plumose setae, outer plate with 6 robust setae, palp with rows of distal and facial setae. Upper and lower lip, maxilla 2 and maxilliped with basic characters for the genus.

Gnathopod 1, subchelate, coxa anteroventral corner produced and rounded, ventral margin with some long setae; basis, posterior margin with 7 long setae; merus densely setose distally; carpus densely setose, about 1.6 X longer than broad; propodus with long facial and marginal setae, palm acute, minutely serrate and slightly convex, with 14 facial robust setae, defined by a comb of 4 robust setae; palmar serration slightly surpass the palmar corner; posterior margin with 3 robust setae; dactylus reaching the end of palm. Gnathopod 2 subchelate; basis with 5 long setae on posterior margin; merus with posteroventral corner produced and acute; carpus posteroventral corner produced, acute and setose; propodus setose along posterior and anterior margin, palm acute, with medial concave portion, bearing a triangular process near hinge of dactylus with 10 robust setae, palmar corner defined by two acute process; dactylus closing between two process of palmar corner, strongly curved, posterior margin sinuous, apically blunt. Pereopod 3, coxa longer than wide (1.8 X); basis with long setae on posterior margin; merus 1.1 X propodus length with anterodistal angle slightly produced; carpus with 9 robust setae on posterior margin; propodus with robust setae on posterior margin; dactylus short, about 0.3 X propodus length. Pereopod 4 similar to pereopod 3, but coxa 1.1 X as long as wide with posterior margin concave. Pereopod 5 coxa wider than long, excavate ventrally; basis posterior margin slightly concave, serrate, with very slender long setae, posteroventral corner subquadrate. Pereopod 6 coxa wider than long, excavate ventrally; basis posterior margin slightly concave, serrate, with very slender long setae; posteroventral corner subquadrate. Pereopod 7 coxa with posterior lobe produced ventrally; basis convex, posterior margin serrate with very slender long setae, posteroventral corner rounded; merus posterodistal margin narrowly subquadrate; propodus 1.2 X carpus length, posterodistal angle expanded, posterior margins with 3 tufts of long setae.

Epimeron 3 posterior and posteroventral margin smooth, posteroventral corner produced in a sharp spine. Uropod 1 peduncle with basofacial robust seta, two displaced robust setae distally, without distoventral spur, 5 and 6 robust setae on outer and inner margins, respectively; inner ramus subequal in length to peduncle, with 4 marginal setae and 5 distal robust setae. Uropod 2 peduncle with 2 distal robust setae; inner ramus subequal in length to peduncle, with 6 marginal robust setae and 3 distal robust setae. Uropod 3 peduncle with 2 distal robust setae; outer ramus about 2.4 X peduncle length with 4 tufts of long setae; inner ramus subequal to outer ramus with inner margin naked. Telson cleft, each lobe with a distal notch bearing 2 apical robust setae, the longer seta not overreaching the tips of each lobe.

Female (sexually dimorphic characters)

Based on paratype female, 8.1 mm. Gnathopod 1 basis with long setae on posterior margin; carpus not lobate, posterior margin densely setose; propodus longer than carpus (1.1 X), palm acute, convex, end of palm defined by a large robust setae, after this one follow 8 robust setae; dactylus with a subdistal spine. Gnathopod 2 basis slender; carpus 0.45 X propodus length with one robust seta on anterior margin, angle posterodistally produced, posterior margin densely setose; propodus 2 X longer than wide, posterior margin subparallel to anterior margin with marginal long setae, palm acute, minutely serrate with 9 marginal robust setae, 3 facial robust setae, palmar corner absent. Telson with the longer distal seta overreaching the tips of each lobe.

Remarks. Elasmopus karamani sp. nov. is closely related to E. balkomanus Thomas and Barnard, 1989 , from Florida, E. lejeunei sp. nov., and E. lemaitrei Ortiz and Lalana, 1994 , from Cuba, in having the posterior margin of basis of pereopod 5 concave, epimeron 3 produced in a sharp spine, and each lobe of telson with distal notch, with at least two robust setae, both in male and female. Nevertheless, E. karamani sp. nov. differs from these species by the article 3 of mandibular palp longer than article 2, in the form of male gnathopod 2, which has propodous rectangular shaped, palm with a medial concave portion, a triangular process near hinge of dactylus, and the palmar corner defined by two acute process, basis of pereopods 5–7 with marginal long setae, basis of pereopod 6 slightly concave and rami of uropod 3 much longer (about 2.4 X) than peduncle. Moreover, E. karamani sp. nov. resembles E. spininamus Walker, 1904 , from Pacific Ocean, in having article 3 of mandibular palp longer than article 2, rami of uropod 3 more than twice of peduncle length and the presence of a spine on epimeron 3. On the other hand, in E. karamani sp. nov. the gnathopod 2 has dense long setae on both anterior and posterior margins, as well its palm lacks marginal robust setae and is defined by 2 acute processes.

Geographic distribution. Brazil: Fernando de Noronha Chain; and off Ceará State coast ( Figure 7 ).

Figures

FIGURE 1. Elasmopus karamani sp. nov. Holotype, male, 8.5 mm, REVIZEE Score NE, # 85 A-III, 3 ° 28 ’ 12 ” S- 35 ° 03 ’ 36 ” W, 04 / VI / 1998, MNRJ 21571. Scale bars = 0.2 mm.

FIGURE 2. Elasmopus karamani sp. nov. Holotype, male, 8.5 mm, REVIZEE Score NE, # 85 A-III, 3 ° 28 ’ 12 ” S- 35 ° 03 ’ 36 ” W, 04 / VI / 1998, MNRJ 21571. Paratype, female, 8.1 mm, REVIZEE Score NE, # 85 A-III, 3 ° 28 ’ 12 ” S- 35 ° 03 ’ 36 ” W, 04 / VI / 1998, MNRJ 21578. Scale bars = 0.2 mm.

FIGURE 3. Elasmopus karamani sp. nov. Holotype, male, 8.5 mm, REVIZEE Score NE, # 85 A-III, 3 ° 28 ’ 12 ” S- 35 ° 03 ’ 36 ” W, 04 / VI / 1998, MNRJ 21571. Paratype, female, 8.1 mm, REVIZEE Score NE, # 85 A-III, 3 ° 28 ’ 12 ” S- 35 ° 03 ’ 36 ” W, 04 / VI / 1998, MNRJ 21578. Scale bars = 0.2 mm.

FIGURE 7. Distribution of Elasmopus karamani sp. nov. and E. lejeunei sp. nov.; circle (●): occurrence of E. karamani sp. nov.; triangle (˔): occurrence of E. lejeunei sp. nov.; square (․): occurrence of both species.