Cymadusa trindadensis, 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 : 378-384

Cymadusa trindadensis sp. nov.

( Figs 12–15 )

Etymology. The specific epithet was given after the Trindade Island, which is located the type-locality of the new species.

Material examined. Holotype, male, dissected and drawn, 5.8 mm, 12 February to 1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col., without depth and substrate information, UFBA 1620 . Paratypes: 1 female, dissected and drawn, 6.8 mm, 12 February to 1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col., without depth and substrate information, UFBA 2044 ; 1 male, dissected and drawn, 5.4 mm, 12 February–1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col.,without depth and substrate information, UFBA 2045 ; 1 male, dissected and drawn, 4.5 mm, 12 February–1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col., without depth and substrate information, UFBA 2046 ; 8 females, 4 males and 8 juveniles, 12 February–1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col., without depth and substrate information, UFBA 2047 ; 7 females, 4 males, 9 juveniles, 12 February–1 March 1976, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil, B. Prazeres, col., without depth and substrate information, MNRJ 10032 .

Diagnosis. Antenna 1, accessory flagellum 2-articulate.Antenna 2 weakly setose.Lower lip setose. Mandible, palp 3-articulate.Maxilla 1, inner plate with 7 setae. Gnathopod 1, coxa produced anteriorly; merus small and subacute; carpus elongated and subrectangular with subacute lobe. Gnathopod 2, coxa suboval; merus small and subacute; carpus subtriangular; palm strongly escavated; palmar spine absent. Uropod 3, peduncle with 4 distal stout setae and 4 long simple setae.Telson subtriangular.

Description. Based on holotype, male, 5.8 mm, UFBA 1620. Head, eyes rounded and well developed. Antenna 1 weakly setose; accessory flagellum 2-articulate. Antenna 2 weakly setose. Upper lip rounded, setose apically and marginally. Lower lip notched inner and outer lobes setose apically. Right mandible, incisor and lacinia mobilis multicuspidate, accessory setal row with 7 stout multicuspidate setae. Left mandible, molar triturative, incisor and lacinia mobilis multicuspidate, accessory setal row with 8 stout multicuspidate setae; palp 3- articulate, article 1 about 3 × longer than wide with 1 long setae laterally, article 2 about 2.7 × longer than wide with 3 long setae laterally, article 3 about 2.6 × longer than wide, with 6 long pectinate setae apically. Maxilla 1, inner plate small and subrectangular, apical margin with 7 long setae; outer plate with 7 stout multicuspidate setae apically; palp 2-articulate, apical margin with 5 stout setae and 7 long setae. Maxilla 2, inner plate about 2.4 × longer than wide, inner and apical margins setose with long plumose setae; outer plate about 2.1 × longer than wide, apical margin setose with long plumose setae. Maxilliped, inner plate about 2.3 × longer than wide, inner and apical margins with both long and setose setae; outer plate about 2.4 × longer than wide, inner margin with 10 stout setae, apical margin with 7 long plumose setae, lateral margin with 8 long setae; palp 4-articulate, 1.6 × longer than outer plate, article 1 small and subrectangular, article 2 subrectangular with row of long setae on the inner margin, article 3 inner margin and apical margins with long setae, article 4 with tiny setaeon the inner margin and 5 short setae apically, nail present.

Gnathopod 1, smaller than gnathopod 2; coxa subrectangular, produced anteriorly, ventral margin bearing row of setae; basis 2.6 × longer than wide, anterior margin with 5 setae, posterior margin with 10 setae; ischium small and subrectangular, 1.7 × longer than wide, anterior margin with 1 short setae, posterior margin with 2 long setae; merus 1.7 × longer than wide, posterior margin with long setae; carpus 1.9 × longer than wide, anterior margin with few setae, posterior margin slightly serrated with long setae, lateral margin with 10 setae; propodus 2 × longer than wide, anterior margin with 3 setae, anterior margin setose and 1 stout setae with accessory setae, lateral margin with both long and short setae; palm acute; dactylus 1.7 ×longer than palm, serrated. Gnathopod 2, coxa suboval, ventral margin with long setae; basis 2.7 × longer than wide, anterior and posterior margins with few setae; ischium small and subrectangular, 1.1 × longer than wide, posteroventral angle with 3 short setae; merus 2.4 × longer than wide, posterior margin with 2 long setae, posteroventral angle with 7 long setae; carpus 1.2 × wider than long, anterior margin with 13 setae, posteroventral angle setose with long pectinate setae; propodus 1.3 × longer than wide, anterior margin with row of long setae, anterodistal angle with tuft of long setae, posterior margin with long setae; palm acute, strongly concave; dactylus subequal to palm, strongly curved, serrated. Pereopod 3, coxa absent; basis 2.9 × longer than wide, anterior margin with 8 setae, posterior margin with ten setae; ischium small and subrectangular, 1.1 × longer than wide, posteroventral angle with 2 setae; merus 2.1 × longer than wide, anterior margin with 2 setae, anterodistal angle produced anteriorly with a tuft of 7 setae, posterior margin with 5 setae; carpus 2.7 × longer than wide, anterior margin with 3 setae, posterior margin with both long and short setae; propodus 3.2 × longer than wide, anterior margin with 4 setae, anterodistal angle with 4 long setae, posterior margin with both long and short setae; dactylus slightly curved. Pereopod 4, coxa absent; basis 2.5 × longer than wide, anterior margin with 7 setae, posterior margin with 9 long setae; ischium small and subrectangular, 1.1 × longer than wide, posteroventral angle with 5 setae; merus 2 × longer than wide, anterior margin with 3 setae, anterodistal angle produced anteriorly with 4 long setae, posterior margin with 7 setae; carpus 2.5 × longer than wide, anterior margin with 3 setae, posterior margin with both long and short setae; propodus 3.3 × longer than wide, anterior margin with 2 long setae, anterodistal angle with 4 long setae, posterior margin with both long and short setae; dactylus slightly curved. Pereopod 5, coxa, ventral margin rounded with both long and short setae, lobe with 2 short setae; basis ovoid, 1.1 X longer than wide, anterior margin with 3 stout setae and both long and short setae, posterior margin with 2 setae; ischium small and subrectangular, 1.2 × wider than longe; merus robust, 1.1 × longer than wide, anterior margin with 6 setae, posterior margin with 3 setae; carpus, robust, 1.3 × longer than wide, anteroventral angle with 4 setae, posterior margin with 4 long setae, posteroventral angle with 3 long setae; propodus, robust, 2.9 × longer than wide, anterior margin with 6 setae, anterodistal angle with 7 long setae, posterior margin with 5 stout setae with accessory setae and long setae; dactylus slightly curved. Pereopod 6, basis 1.4 × longer than wide, expanded posteriorly, anterior margin with 5 setae, posterior margin with 7 setae; ischium small and subrectangular, slightly longer than wide, anterior margin with 2 setae; merus 2.3 × longer than wide, anterior margin with 2 short setae, anterodistal angle with 4 setae, posterior and posteroventral angle with 2 setae each; carpus 2.5 × longer than wide, posterior margin with 3 setae, anterodistal angle with 5 setae and 1 pectinate setae, posterior margin with 5 long setae, posteroventral angle with 4 long pectinate setae; propodus 5.5 × longer than wide, anterior margin with long setae and 2 stout setae, posterior margin with 7 long setae, posteroventral angle with 9 long setae, facial margin with 7 long setae; dactylus curved. Pereopod 7, coxa ovoid, without setae; basis 1.7 × longer than wide, anterior margin with 6 short setae, posterior margin with 2 long stout setae; ischium small and subrectangular, 1.3 × longer than wide, anterior margin with 4 setae; merus 3.2 × longer than wide, anterior and posterior margins with 3 setae each, anterodistal angle with 5 setae, posterodistal angle with 2 long setae; carpus 3.3 × longer than wide, anterior margin with 4 long setae, anterodistal angle with 5 setae, posterior margin with 3 long setae, posteroventral angle with a tuft of setae; propodus 4.6 × longer than wide, anterior margin with 4 stout setae with accessory setae and 6 long setae, posterior margin with 6 long setae, posteroventral angle with 7 long setae; dactylus curved.

Epimeral plates 1–3 rounded, without setae. Uropod 1 peduncle with very long and acute distoventral spine (spur); peduncle 3 × longer than wide, dorsal margin with 4 stout setae with accessory setae, dorsolateral margin with 2 stout setae, lateral margin with row of long setae; inner ramus 1.2 × longer than outer ramus, apical margin with 2 stout setae with accessory setae and 2 stout setae; outer ramus, dosal margin with 3 stout setae with accessory setae, apical margin with 3 stout setae with accessory setae and 2 stout setae. Uropod 2, peduncle 2 × longer than wide, dorsal and lateral margins with 1 stout setae with accessory setae each; inner ramus 1.2 × longer than outer ramus, dorsal margin with 3 stout setae, dorsolateral margin with 2 stout setae with accessory setae, apical margin with 1 stout setae and 3 stout setae with accessory setae; outer ramus, dorsolateral margin with 2 stout setae and 1 stout setae with accessory setae, apical margin with 2 stout setae and 2 stout setae with accessory setae. Uropod 3, peduncle 1.4 × longer than wide with 4 long setae and 4 stout setae distally; inner ramus slightly longer than outer ramus, apical margin with 4 stout setae and 4 long setae; outer ramus, lateral margin with 1 short setae, apical margin with 2 curved stout setae. Telson subtriangular, lateral margins with 1 proximal plus 1 subapical long seta each.

Sexual dimorphic characters. Based on paratype, female, 6.8 mm, UFBA 2044. Gnathopod 1, smaller than gnathopod 2; coxa subrectangular, produced anteriorly, ventral margin setose; basis 2.9 × longer than wide, anterior margin with 3 setae, posterior margin with 6 setae; ischium small and subrectangular, 1.2 × longer than wide, posterior margin with 2 setae; merus 1.6 × longer than wide, posterior margin with long pectinate setae, lateral margin with 5 long setae; carpus 1.8 × longer than wide, anterodistal angle with 4 long setae, lateral and posterior margins setose with both long and pectinate setae; propodus 1.7 × longer than wide, anterior and lateral margins with long setae, posterior margin setose with both long and pectinate setae and 1 stout setae with accessory setae; palm acute; dactylus 1.4 × longer than palm, serrated. Gnathopod 2 coxa subrectangular, ventral margin setose and rounded; basis 2.5 × longer than wide, anterior margin with 6 setae, anterodistal lobe produced anteriorly, posterior margin with 7 setae, lateral margin with setae; ischium small and subrectangular, 1.1 × longer than wide, posterior margin with 3 setae; merus 1.8 × longer than wide, posterior margin with both pectinate and simple long setae, lateral margin with long setae; carpus 1.1 × longer than wide, anterior margin setose, posteroventral angle with long pectinate setae, lateral margin with long setae; propodus 1.5 × longer than wide, anterior and lateral margins setose, anterodistal angle with a tuft of long setae, posterior margin setose with both pectinate and simple long setae; palm acute, with a small concavity; dactylus 1.4 × longer than palm, serrated.

Remarks. As the material examined was collected almost 40 years ago, all the specimens had the antennae 1– 2 totally damaged or lost because of the long time stored in the collections. However, C. trindadensis sp. nov. can be easily distinguished by the other species of the genus by the following distinct and evident characters: male gnathopod 2, palm strongly excavated, dactylus strongly curved; uropod 1, spur strongly elongated and acute, almost half of peduncle’s length.

Distribution. Known only to the type-locality, Trindade Island (20°31’29”S, 29°19’29”W), Espírito Santo state, Brazil.

Figures

FIGURE 12. Cymadusa trindadensis sp. nov. Holotype, male, 5.8 mm, UFBA 1620, Trindade Island, Espírito Santo state, Brazil; paratype, male, 5.4 mm, UFBA 2045, Trindade Island, Espírito Santo state, Brazil; paratype, male, 4.5 mm, UFBA 2046, Trindade Island, Espírito Santo state, Brazil. Scale bars: 0.5 mm for Hd; 0.2 mm for A 1 – 2; 0.1 for the remainder.

FIGURE 13. Cymadusa trindadensis sp. nov. Holotype, male, 5.8 mm, UFBA 1620, Trindade Island, Espírito Santo state, Brazil; paratype, female, 6.8 mm, UFBA 2044, Trindade Island, Espírito Santo state, Brazil. Scale bars: 0.5 mm.

FIGURE 14. Cymadusa trindadensis sp. nov. Holotype, male, 5.8 mm, UFBA 1620, Trindade Island, Espírito Santo state, Brazil. Scale bars: 0.5 mm.

FIGURE 15. Cymadusa trindadensis sp. nov. Holotype, male, 5.8 mm, UFBA 1620, Trindade Island, Espírito Santo state, Brazil. Scale bars: 0.5 mm for Ep 1 – 3; 0.1 mm for the remainder.