Cymadusa ygara, Andrade, Luiz F. & Senna, André R., 2017

Andrade, Luiz F. & Senna, André R., 2017, Two new species of Ampithoidae (Crustacea: Amphipoda) from northeastern Brazil, Zootaxa 4282 (3), pp. 487-500 : 494-499

Cymadusa ygara sp. nov.

( Figs 6–9 )

Material examined. Holotype, female, dissected and drawn, 10.7 mm, 0 2 June 2012, Icapuí Beach, municipality of Icapuí , Ceará state, Brazil, in sandstone reefs in the intertidal zone, J. Alves Col., CRFFP 73

Diagnosis. Antenna 1, accessory flagellum 2-articulate. Mandible palp 3-articulate. Maxilla, inner plate with 6 plumose setae. Gnathopod 1 weakly setose. Gnathopod 2, coxa bilobate; palm slightly concave, with a stout setae defining palm. Pereopods 3–5, coxa bilobate. Uropod 3, peduncle with 6 distal stout setae. Telson distally convex, with 2 apical cusps.

Description. Based on holotype female 10.7 mm, CRFFP 73.

Head. Eyes rounded and well developed. Antenna 1 weakly setose, longer than antenna 2; peduncular article 1 slightly shorter than article 2, article 2 about 3.7 × longer than article 3; flagellum 34-articulate; accessory flagellum 2-articulate. Antenna 2 weakly setose; peduncular article 5 slightly shorter than article 4; flagellum 24- articulate. Upper lip rounded, apically setose. Lower lip notched; lateral lobe longer than medial. Right mandible molar triturative with two long setae; incisor and lacinia mobilis multi-cuspidate; accessory setal row not observable; palp 3-articulate, article 2 subequal to article 3 and 1.8 × longer than article 1, article 3 with 10 pectinate long setae apically. Left mandible molar triturative with a long setae; incisor and lacinia mobilis multicuspidate; accessory setal row with 7 stout multicuspidate setae; palp 3-articulate, article 2 subequal to article 3 and 1.5 × longer than article 1, article 3 with 10 pectinate long setae apically; Maxilla 1 inner plate small and subrectangular, with 6 plumose setae; outer plate with 8 stout multicuspidate setae apically; palp 2-articulate, inner margin with 2 setae, apical margin with 7 stout and 1 long setae, lateral margin with 5 long setae. Maxilla 2 inner plate 3.1 × longer than wide, inner and apical margins covered with long plumose setae; outer plate slightly longer than inner plate, about 2.4 × longer than wide, inner and outer margins covered with small setules and long setae. Maxilliped inner plate 3 × longer than wide, inner and apical margins covered with long plumose setae, presenting a stout setae apically; outer plate 1.9 × longer than wide, inner margin covered with small stout setae, apical margin with 4 long setae; palp 4-articulate, about 1.5 × longer than outer plate; article 1 with 7 setae on the inner margin, article 2 with a row of setae on the inner margin, article 3 inner margin covered with long setae, apical margin with 3 pectinate and 1 regular long setae, outer margin with 6 long setae, article 4 with 2 pectinate setae on the inner margin, nail present.

Pereon. Gnathopod 1 weakly setose; coxa slightly produced anteriorly, ventral margin bilobate with a row of long and short setae; basis 3.2 × longer than wide, posterodistal lobe small and rounded with 1 short setae, posterior and lateral margins with short and long setae; ischium small and subrectangular, posterior margin with 2 setae; merus produced to form a small subacute lobe with 3 long setae; carpus subtriangular, 1.7 × longer than wide, anterior margin with 1 setae and 2 long setae distally, posterior margin covered with long and short setae; propodus anterior margin with sparse setae and a tuft of setae distally, inner margin with a row of short setae; palm acute, covered with short setae; dactylus slightly longer than palm. Gnathopod 2 weakly setose; coxa, ventral margin bilobate with short and long setae; basis 2.8 × longer than wide, posterodistal lobe small and rounded; posterior margin with 1 setae distally; ischium small and subtriangular, posterior margin with 3 setae; merus produced to form a small subacute lobe with 7 long setae; carpus subtriangular, anterior margin with 2 short setae and a tuft of long setae distally, posterior margin with row of short and long setae; propodus anterior margin with sparse setae and a tuft of long setae distally, posterior margin with a row of long setae; palm acute, slightly concave, covered with short and long setae, palmar corner with a stout setae defining palm. Pereopod 3 coxa bilobate, ventral margin covered short setae; basis 2.8 × longer than wide, anterior margin with 3 short setae, posterior margin with plumose long and short setae; ischium small and subquadrate, posterior margin with 3 short setae; merus subrectangular, about 1.8 × longer than wide, anterior margin with 1 setae and a tuft of setae distally, posterior margin with 3 setae and a 4 setae distally; carpus subrectangular, anterior margin with 2 short setae, posterior margin with short and long setae; propodus 3.8 × longer than wide with sparse setae and 3 setae distally. Pereopod 4 very similar to pereopod 3, differing only by some arrangements of setae on coxae, merus, carpus and propodus. Pereopod 5 coxa bilobate, ventral margin with row of tiny setules; basis subovoid, about 1.2 × longer than wide, anterior margin with 5 short stout setae; ischium small and subquadrate; merus subrectangular, about 1.8 × longer than wide; carpus broad, subrectangular, about 1.6 × longer than wide; propodus weakly prehensile, anterior margin with sparse setae and 3 stout short setae, posterior margin with a row of short and long setae, dactylus curved. Pereopod 6 coxa absent; basis about 1.6 × longer than wide, anterior margin with 4 short stout setae, posterior margin with 2 short stout setae; ischium small and subquadrate; merus and carpus very similar, with sparse long and short setae, bearing tuft of setae distally; propodus prehensile, anterior margin with 8 stout setae and sparse long setae, posterior margin with row of short and long setae; dactylus curved. Pereopod 7 coxa small and rounded, anterior margin with 3 setae; basis 1.8 × longer than wide, anterior margin with tiny setules, posterior margin with 3 short stout setae; ischium small and subquadrate; merus and carpus very similar, with sparse long and short setae, bearing tuft of setae distally; propodus prehensile, anterior margin with 11 stout setae and sparse long setae, posterior margin with sparse short and long setae, bearing a tuft of long setae distally; dactylus curved, anterior margin with 1 tiny setule.

Pleon. Epimeron 1, margins rounded. Epimeron 2 anterior margin concave, posteroventral corner with a small subacute tooth. Epimeron 3 anterior margin slightly concave, posteroventral corner with a subacute tooth. Uropod 1 peduncle 3.5 × longer than wide, with 12 stout setae and a long and acute distoventral spine (spur); inner ramus 1.1 × longer than outer ramus, with 5 marginal and 4 apical stout setae; outer ramus with 5 marginal and 4 apical stout setae. Uropod 2 peduncle 2.2 × longer than wide, with 5 stout setae; inner ramus slightly longer than outer ramus, with 4 marginal and 4 apical stout setae; outer ramus with 5 marginal and 4 apical stout setae. Uropod 3 peduncle 1.8 × longer than wide, with 7 marginal long setae and 6 stout and 5 long setae distally; inner ramus slightly longer than outer ramus, with 3 marginal stout setae, 4 stout and 6 long setae distally; outer ramus with 1 marginal stout setae with accessory setae and 2 large recurved distal robust setae. Telson subtriangular and distally convex, with 2 small cusps.

Etymology. The specific epithet is derived from an indigenous word that means “quick canoe”, that latter originated the city name Icapuí .

Remarks. Cymadusa ygara sp. nov. is close to C. herrerae Ortiz & Winfield, 2015 and C. crassicornis ( Costa, 1857) by the following characters: antenna 1 accessory flagellum 2-articulate; epimeron 3 posteroventral corner with an acute tooth; gnathopod 2 weakly setose, palm entire with a stout setae defining palm. However, it presents an exclusive character within the genus: coxae 2–5 bilobate. The new species is established based on a unique female holotype.

Habitat. Cymadusa ygara sp. nov. occurs in sandstone reefs in the intertidal zone.

Distribution. Known only from Icapuí Beach, Ceará state, Brazil.

Figures

FIGURE 6. Cymadusa ygara sp. nov. Holotype, female, 10.7 mm, CRFFP 73, Icapuí Beach, municipality of Icapuí, Ceará state, Brazil. Scale bar: 3.0 mm.

FIGURE 7. Cymadusa ygara sp. nov. Holotype, female, 10.7 mm, CRFFP 73, Icapuí Beach, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm for A 1 – 2; 0.2 mm for the remainder.

FIGURE 8. Cymadusa ygara sp. nov. Holotype, female, 10.7 mm, CRFFP 73, Icapuí Beach, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm.

FIGURE 9. Cymadusa ygara sp. nov. Holotype, female, 10.7 mm, CRFFP 73, Icapuí Beach, municipality of Icapuí, Ceará state, Brazil. Scale bars: 0.5 mm for U 1 – 2; 0.2 mm for U 3 and T; 1.0 mm for the remainder.