Diaptomus curvatus, Perbiche-Neves, Boxshall & Paggi, 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 : 63-67

Taxon classification Animalia Calanoida Diaptomidae

" Diaptomus " curvatus Perbiche-Neves, Boxshall & Paggi, 2013 Figs 84, 85, 86, 87

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

Diagnosis.

Adult male, body length 923 µm. Ur4 with triangular-shaped dorsal process ornamented with small granulations at left distal corner (Figs 84F, 85F, G), length similar to width of Ur4. CR asymmetrical, left ramus larger than right, internal seta of CR with narrow section close to base (Fig. 84F). Segment 11 of A1R with modified seta on anterior margin longer than modified seta on segment 13; spinous processes present on segments 15 and 16 (Figs 84C, 85A, C); segment 20 with small, curved, distal process (Fig. 85E). Two rows of spinules present on surface of Enp1 of A2 (Fig. 84D). Small mammiform process present proximally on internal margin of left and right BspP5 (Fig. 84A); lateral spine on right Exp2P5 strong, inserted proximally, curved in midsection, about 2/3 length of terminal claw (Figs 84A, E, 85D); base of terminal claw thick, almost same width as thinnest part of Exp2P5. Right EnpP5 tapering distally, ornamented with spinules subapically (Figs 84A, 85B). Lateral seta of CxP5L as long as width of segment; BspP5L as wide as long (Fig. 84B).

Adult female, body length 1120 µm. Incomplete suture present between Ped4 and Ped5; dorsal surface smooth, without spinules (Fig. 86A); lateral wings asymmetrical, left wing larger than right. GS slender, asymmetrical, about 1.6 times longer than wide; anterior part slightly dilated, with swelling on left side larger than right. P5 symmetrical (Fig. 86B) with small conical process at distal corner of CxP5, bearing short, triangular sensilla. BspP5 with long external seta, extending beyond base of terminal claw. EnpP5 one-segmented. ExpP5 3-segmented; lateral spine of Exp2 longer than external margin of Exp3P5; external seta of Exp3P5 about two thirds length of internal seta; internal seta reaching mid-length of terminal claw.

Remarks.

Several individuals of this species were found in the Yaciretá Reservoir (Fig. 87, YACI-B) in the middle Paraná River. This species had been found by S. M. Frutos (pers. comm.) in Yaciretá Reservoir, and J. C. Paggi (pers. comm.) found three males in the middle section of the Paraná River in 1971 and in 1993. This species is distinct from all other Diaptomidae found in South America, especially with regard to the P5 and the dorsal process on the Ur4. A preliminary phylogenetic analysis based on morphological characters was inconclusive with regard to which genus this species should be attributed to, thus suggesting the possibility that it represents a new genus. However, Perbiche-Neves et al. (2013) decided to maintain the status as " Diaptomus " sensu lato until a comprehensive phylogenetic analysis of Neotropical diaptomids could be completed.