Diaptomus frutosae, Perbiche-Neves & Boxshall, 2013

Perbiche-Neves, Gilmar, Boxshall, Geoffrey Allan, Previattelli, Daniel, Nogueira, Marcos Gomes & da Rocha, Carlos Eduardo Falavigna, 2015, Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of " de la Plata " River Basin (South America), ZooKeys 497, pp. 1-111 : 68-71

Taxon classification Animalia Calanoida Diaptomidae

" Diaptomus " frutosae Perbiche-Neves & Boxshall, 2013 Figs 88, 89, 90, 91, 92

" Diaptomus " frutosae Perbiche-Neves & Boxshall, 2013 in Perbiche-Neves, Boxshall, Paggi, Rocha, Previattelli & Nogueira, 2013

Diagnosis.

Adult male, body length 1292 µm. Irregular row of spinules present dorsally and laterally along posterior margin of Ped4 (Fig. 88A). Modified seta on segments 11 and 13 well developed, that on segment 13 longest, extending to end of segment 14 (Fig. 89G, H); spinous process well developed on segments 15 and 16 of A1R; spinous process on segment 15 longer than that on segment 16; falciform process on segment 20 of A1R in all specimens analysed (N=16), reaching beyond middle of apical segment, proximal surface of process rugose (Fig. 88G, 89I, J). Right CxP5 with well-developed distal process bearing short sensilla (Fig. 89E). Right Exp1P5 short, about 1.5 times wide than long; right Exp2P5 flattened, subtriangular in shape (Fig. 89 C–D), wider than long, with swollen outer margin proximal to insertion of outer seta (Fig. 89A, C, 88B); outer seta slightly curved (Fig. 88B, 89C). Terminal claw strongly curved near tip (Figs 88 D–F, H, 89F). Strong seta present on distal margin of CxP5L.

Adult female, body length 1346 µm. Incomplete suture present between Ped4 and Ped5; rows of strong spinules marking position of posterior margin of Ped4 (Figs 90A, 91B, C); lateral wings slightly asymmetrical, similar in size; both wings with sensilla at distal tip (Fig. 91A). GS symmetrical, approximately 1.8 times longer than wide; anterior part dilated, with swelling on left side larger than on right; sensilla on apex of each, about 1.8 times longer than wide; swelling on left side hemispherical, swelling on right more conical (Figs 90A, 91F). P5 symmetrical (Fig. 90B), with small conical process at outer distal corner of CxP5, bearing short, strong, triangular sensilla, about 1.5 times longer than wide. BspP5 with long outer seta, about twice length of EnpP5. EnpP5 one-segmented. Exp 3-segmented; lateral spine of Exp2 as long as external margin of Exp3 (Fig. 91D); external seta of Exp3 reaching one third length of internal seta; internal seta almost reaching mid-length of terminal claw; terminal claw with comb of robust spinules in mid-section (Fig. 91E).

Remarks.

The specimens were found in the middle part of the Paraná River (Fig. 92, RPAR-M2) and in the Yaciretá Reservoir (YACI-D). The species was relatively abundant in the samples and occurs in reservoirs and other water bodies near these locations, according to S. M. Frutos (pers. comm.). In a previous phylogenetic analysis, this species was placed close to the genus Scolodiaptomus Reid, 1987, which is monospecific [ Scolodiaptomus corderoi (Wright, 1936)], because they share important features such as the subtriangular shape of Exp2P5R and the presence of modified setae or spinous processes on segments 13, 15 and 16 of the male A1R. However, it is very unlikely that " Diaptomus " curvatus belongs to the genus Scolodiaptomus , which is characterised by an unornamented hyaline lamella on segment 20 of A1R and by the presence of a dorsal cylindrical process on the Ped3. Again, the affinities of this species need to be tested as part of a comprehensive phylogenetic analysis of Neotropical diaptomids. It is likely that this species could be assignable to a new genus.