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

Andrade, Luiz F. & Senna, André R., 2017, Four new species of Cymadusa Savigny, 1816 (Amphipoda: Ampithoidae) and new records of C. filosa Savigny, 1816 from Brazilian coast, Zootaxa 4226 (3), pp. 359-389 : 360-367

Cymadusa icapui sp. nov.

( Figs 1–4 )

Etymology. The species has been named after the type locality, Icapuí Beach.

Material examined. Holotype, male, dissected and drawn, 18.8 mm, 2 June 2012, Cajuais Bank, municipality of Icapuí , Ceará state, Brazil, J. Alves, col., without depth and substrate information, UFBA 1610 . Paratypes: 1 female, dissected and drawn, 12.1 mm, 2 June 2012, Cajuais Bank , municipality of Icapuí , Ceará state, Brazil, J. Alves, col., without depth and substrate information, UFBA 1611 ; 1 female, 17.8 mm, 7 April 2012, municipality of Camocim , Ceará state, Brazil, P. Pachelle, col.,without depth and substrate information, UFBA 1612 ; 2 males, 2 June 2012, Cajuais Bank , municipality of Icapuí , Ceará state, Brazil, J. Alves, col., without depth and substrate information, UFBA 1613 ; 4 females and 1 male, 2 June 2012, Cajuais Bank , municipality of Icapuí , Ceará state, Brazil, J. Alves, col., without depth and substrate information, UFBA 1614 ; 4 females and 1 juvenile, 2 June 2012, Cajuais Bank , municipality of Icapuí , Ceará state, Brazil, J. Alves, col., without depth and substrate information, UFBA 1615 .

Diagnosis. Antenna 1, accessory flagellum 2-articulate.Antenna 2, strongly setose with plumose setae. Mandible, palp 3-articulate. Maxilla 1, inner plate with 5 setae. Gnathopod 1 strongly setose on basis, carpus and propodus for both male and female; merus elongated and acute; carpus strongly elongated, subrectangular and posteriorly serrated. Gnathopod 2 strongly setose on basis, carpus and propodus; palm, inner margin serrated, with a posterodistal small and subacute spine. Pereopod 3, coxa, ventral margin with dense row of long and plumose setae. Uropod 3, peduncle with 6 distal stout setae bearing accessory setae; inner ramus with an apical denticulate seta.

Description. Based on holotype, male, 18.8 mm, UFBA 1610. Head, eyes rounded and well developed. Antenna 1 weakly setose, longer than antenna 2; flagellum 36-articulate; accessory flagellum 2-articulate. Antenna 2 strongly setose; flagellum 33-articulate; articles 3–5 covered by long and plumose setae. Upper lip rounded, apically setose. Lower lip notched, inner and outer lobes setose apically. Right mandible, molar triturative without setae; incisor and lacinia mobilis multicuspidate; accessory setal row with 5 stout multicuspidate setae.Left mandible, molar triturative with 2 long plumose setae; incisor and lacinia mobilis multicuspidate; accessory setal row with 7 stout multicuspidate setae; palp 3-articulate, article 1 about 1.7× longer than wide, article 2 about 2.2× longer than wide with 3 long setae on the lateral margin, article 3 about 2.4× longer than wide with thirteen long pectinated setae apically. Maxilla 1, inner plate small and subtriangular, inner margin with 5 long plumose setae; outer plate with 8 stout and multicuspidate setae apically; palp 2-articulate, inner margin with 5 long setae, outer margin with 2 long setae, facial margin with 2 long setae, and 6 stout pectinated setae apically. Maxilla 2, inner plate about 3.1× longer than wide, inner and apical margin strongly covered with long plumose setae; outer plate longer than inner plate, about 4.2 × longer than wide, inner and apical margin setose with tiny setae and plumose setae, outer margin row of tiny setae; apical margin covered with tiny setae. Maxilliped, inner plate about 3 × longer than wide, inner margin with long setae, apical margin with 11 long pectinated setae; outer plate about 1.7 × longer than wide, inner margin with 13 short stout setae, outer and apical margin with 8 long plumose setae; palp 4- articulate, about 1.7 × longer than outer plate, article 1 subrectangular with 2 long setae on the outer margin, article 2 subrectangular with a row of long setae on the inner margin, article 3 subrectangular with setose inner margin, outer margin with 7 long setae and 4 long pectinated setae distally, article 4 with tiny setae on the inner margin, nail present.

Gnathopod 1, smaller than gnathopod 2; coxa subquadrate, slightly produced anteriorly, ventral margin setose; basis subrectangular, about 3.8 × longer than wide, anterior margin with plumose setae; ischium small and subrectangular, 1.6 × longer than wide, posterior margin with 2 small setae; merus 2.4 × longer than wide, posterior margin setose; carpus strongly elongated, 3.5 × longer than wide, anterior margin with simple and plumose setae laterally, posterior margin serrated and setose; propodus 2 × longer than wide, anterior margin with long setae, posterior margin setose, anterodistal angle with a tuft of long setae; palm slightly acute; dactylus 1.4 ×longer than palm, serrated and with tiny setae. Gnathopod 2, strongly setose on basis, carpus and propodus; coxa subrectangular, ventral margin setose with plumose setae; basis 3.2 × longer than wide, anterior margin setose, posterior margin with 7 long setae; ischium small and subtriangular, 1.3 × longer than wide, posteroventral angle with a small seta; merus 2.3 × longer than wide, posteroventral angle with row of long setae; carpus 1.3 × longer than wide, anterior margin setose, posterior margin setose with long and pectinate setae; propodus 1.5 × longer than wide, anterior and posterior margins setose; palm slightly concave, defined by an obtuse angle; dactylus subequal to palm. Pereopod 3, coxa subrectangular, ventral margin densely covered with plumose setae; basis 3 × longer than wide, anterior margin with row of plumose setae, posterior margin with both long and short setae; ischium small and subrectangular, 1.6 × longer than wide, without setae; merus 2.1 × longer than wide, anterodistal angle with a tuft of 8 long setae, posterior margin with long setae; carpus 2.7 × longer than wide, posterior margin setose; propodus 4.6 × longer than wide, anterodistal angle with 3 setae, posterior margin with long setae; dactylus slightly curved. Pereopod 4, coxa subrectangular, ventral margin setose with long plumose setae; basis 2.5 × longer than wide, anterior margin with long setae and row of plumose setae, posterior margin with setae; ischium small and subrectangular, 1.1 × longer than wide, posteroventral angle with 4 long setae; merus 1.9 × longer than wide, anterodistal angle with tuft of setae, posterior margin with both long and short setae; carpus 2.6 × longer than wide, anterior margin and anterodistal angle with 2 setae each, posterior margin setose; propodus 2.8 × longer than wide, anterior margin with few setae, posterior margin with both long and short setae; dactylus slightly curved. Pereopod 5, coxa, ventral margin setose with plumose setae and tiny setae; basis ovoid, 1.1 × longer than wide, anterior margin with 7 stout setae with accessory setae and few simple setae, posterior margin with few setae; ischium small and subrectangular, 1.1 × longer than wide, anterior margin with 2 setae; merus 1.8 × longer than wide, anterior and posterior margins with 6 setae each; carpus 2.2 × longer than wide, anterior and posterior margins with both long and short setae; propodus 3.8 × longer than wide, anterior margin with long setae and 5 stout setae with accessory setae, posterior margin with both long and short setae, posterodistal angle with tuft of long setae; dactylus slightly curved. Pereopod 6, coxa, ventral and posterior margin with few setae; basis 1.7 × longer than wide, anterior and posterior margins with 4 stout setae with accessory setae each; ischium small and subrectangular, slightly longer than wide, anterior margin with 3 setae; merus 3.6 × longer than wide, anterior and posterior margins with setae; carpus 3.4 × longer than wide, anterior and posterior margins with setae; propodus 6.1 × longer than wide, anterior margin with 7 stout setae and few long setae, posterior margin with setae, posterodistal angle with a tuft of long setae; dactylus curved. Pereopod 7, basis 1.6 × longer than wide, anterior margin with 3 stout setae with accessory setae, anterodistal angle with 3 setae, posterior margin with 3 stout setae with accessory setae and 8 tiny setae; ischium small and subrectangular, slightly longer than wide, anterior margin with 4 setae; merus 3.1 × longer than wide, anterior and posterior margins with setae; carpus 3 × longer than wide, anterior and posterior margins with setae; propodus 5.7 × longer than wide, anterior margin with 6 stout setae with accessory setae and few long setae, posterior margin with setae, posteroventral angle with a tuft of long setae; dactylus curved.

Epimeral plate 1, without setae, posteroventral angle slightly rounded. Epimeral plate 2, without setae, posteroventral angle slightly rounded, defined by a slight concavity. Epimeral plate 3, without setae, posteroventral angle slightly rounded, ventral margin with concavity.Uuropod 1, peduncle with long and acute distoventral spine (spur); peduncle 2.7 × longer than wide, dorsal margin with 3 stout setae with accessory setae, dorsolateral margin with 5 stout setae, lateral margin with setae; inner ramus 1.2 × longer than outer ramus, dorsal margin with 5 stout setae with accessory setae, dorsolateral margin with 1 stout setae and 2 stout setae with accessory setae, apical margin with 4 stout setae and 1 stout seta with accessory seta; outer ramus, dorsal margin with 3 stout setae with accessory setae, dorsolateral margin with 5 stout setae with accessory setae, apical margin with 3 stout setae and 2 stout setae with accessory setae. Uropod 2, peduncle 2.3 × longer than wide, dorsal margin with 2 stout setae with accessory setae, dorsolateral margin with 3 stout setae, lateral margin with 4 tiny setae; inner ramus 1.1 × longer than outer ramus, dorsal margin with 4 stout setae with accessory setae, dorsolateral margin with 3 stout setae with accessory setae, apical margin with 2 stout setae with accessory setae and 1 stout setae; outer ramus, dorsal margin with 3 stout setae with accessory setae, dorsolateral margin with 3 stout setae with accessory setae and 1 stout setae, apical margin with 2 stout setae with accessory setae and 3 stout setae. Uropod 3, peduncle 2.3 × longer than wide with 4 stout setae with accessory setae distally, dorsal margin with 4 stout setae with accessory setae, lateral margin with long setae; inner ramus 1.2 × longer than outer ramus, dorsal margin with 2 stout setae with accessory setae, dorsolateral margin with 1 stout setae with accessory setae and 1 stout setae, apical margin with 7 long setae, 4 stout setae with accessory setae, 1 stout setae and 1 denticulate setae; outer ramus, dorsolateral margin with 2 stout setae with accessory setae, lateral margin with 3 long setae, apical margin with 2 curved stout setae. Telson, slightly rounded, lateral margin with 4 setae, distolateral angles with1 cusp plus a short plumose seta each, a row of 6 setae and 1 long seta and a row of 5 setae and 1 long seta nearby each cusps respectively.

Sexual dimorphic characters. Based on paratype, female, 12.1 mm, UFBA 1611. Gnathopod 1, smaller than gnathopod 2; coxa subrectangular, produced anteriorly, ventral margin setose; basis subrectangular, 3.8 × longer than wide, anterior and posterior margin with few setae; ischium small and subrectangular, 1.1 × longer than wide, posterior margin with 3 setae; merus 2.6 × longer than wide, posterior margin with long setae; carpus about 2.2 × longer than wide, anterior margin with 3 setae, posterior margin setose, anterodistal angle with 3 long setae; propodus 1.7 × longer than wide, anterior margin with 8 long setae, posterior margin setose, lateral margin with setae; palm acute; dactylus slightly longer than palm, serrated and with tiny setae. Gnathopod 2, coxa subrectangular, ventral margin setose; basis 3.2 × longer than wide, anterior and posterior margins with few setae; ischium small and subrectangular, as long as wide, posteroventral angle with 4 long setae; merus 1.7 × longer than wide, posterior margin with long setae; carpus as long as wide, anterior margin with 2 long setae, anterodistal angle with 5 setae, posterior margin with long pectinate setae; propodus 1.4 × longer than wide, anterior margin with long setae, anterodistal angle with tuft of long setae, posterior margin setose; palm slightly acute, concave; dactylus 1.3 × longer than palm with tiny setae.

Remarks. Cymadusa icapui sp. nov. appears to be morphologically close to the species that compound the C. filosa complex. The new species resembles C. filosa and C. setosa by the following characters:weakly produced coxa 1; setose antennae and gnathopods; elongated carpus of gnathopod 1. Cymadusa icapui sp. nov. can be distinguished from C. filosa and C. setosa by the following characters ( C. filosa and C. setosa characters in parenthesis): setose lower lip (poorly setose); gnathopod 1, carpus much more elongated (regularly elongated); coxa 3, ventral margin densely setose (weakly setose).

Cymadusa icapui sp. nov. presents the following distinct and unique characters in the genus: pereopod 3, coxa, ventral margin with a very dense row of long plumose setae; uropod 3, inner ramus, apical margin with a denticulate seta.

Distribution. Cajuais Bank, Icapuí Beach, municipality of Icapuí , Ceará state, Brazil (type-locality); Praia de Camocim, municipality of Camocim, Ceará state, Brazil.

Figures

FIGURE 1. Cymadusa icapui sp. nov. Holotype, male, 18.8 mm, UFBA 1610, Cajuais Bank, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm for A 1 – 2; 0.5 mm for Hd; 0.2 mm for the remainder.

FIGURE 2. Cymadusa icapui sp. nov. Holotype, male, 18.8 mm, UFBA 1610, Cajuais Bank, municipality of Icapuí, Ceará state, Brazil; paratype, female, 12.1 mm, UFBA 1611, Cajuais Bank, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm.

FIGURE 3. Cymadusa icapui sp. nov. Holotype, male, 18.8 mm, UFBA 1610, Cajuais Bank, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm.

FIGURE 4. Cymadusa icapui sp. nov. Holotype, male, 18.8 mm, UFBA 1610, Cajuais Bank, municipality of Icapuí, Ceará state, Brazil. Scale bars: 1.0 mm for Ep 1 – 3; 0.5 mm for U 1; 0.2 mm for the remainder.