Bidessodes

Braga, Rafael Benzi & Ferreira-Jr, Nelson, 2009, Three new species of Bidessodes Régimbart (Insecta, Coleoptera, Dytiscidae) from the Amazon river floodplain, Zootaxa 2034, pp. 43-48 : 46-47

Bidessodes (s. str.) demarcoi Braga & Ferreira-Jr., new species

( Fig. 3 )

Diagnosis. Elytra dark brown with darker longitudinal fasciae ( Fig. 3 a). Prosternal process subparallel-sided and with apex acuminate ( Fig. 3 b). Middle tibiae straight in both sexes. Last visible sternite with sulcus near apex and a pair of dark lateral apical spots ( Fig. 3 c). Aedeagus in lateral view broad, slightly curved, with apex sinuous ( Figs 3 d–f). Parameres in dorsal view covering the basal two-thirds of aedeagus; apices inwardly curved ( Figs 3 d, e).

Description. Holotype male: total length 2.62 mm; maximum width 1.22 mm; maximum length of the head 0.32 mm; elytral length 1.92 mm; maximum width of the pronotum 1.02 mm.

Body fairly oblong with lateral margins subparallel, slight angle present between pronotum and elytra; surface covered with shallow and fine punctation; pubescence consisting of numerous metallic iridescent setae; setae denser on pronotum and elytra ( Fig. 3 a). Head with eyes emarginate; cervical region smooth, without punctures, setae, or stria. Pronotum with basal striae and without transverse furrow; prosternal process with lateral margins subparallel and apex acuminate ( Fig. 3 b). Legs with three basal tarsomeres expanded on fore and middle tarsi; middle tibiae straight; coxal lines raised and parallel. Elytra without striae, sutural lines or rows of punctures; epipleurae without transverse carina. Last visible sternite with sulcus near apex and a dark spot on each side of the sulcus ( Fig. 3 c). Aedeagus in lateral view broad, slightly curved, with apex sinuous ( Figs 3 d–f). Parameres in dorsal view covering basal two-thirds of aedeagus; apices curved ( Figs 3 d, e).

Coloration. Head and pronotum brown. Elytra brown with darker longitudinal fasciae; lateral and mesal fasciae discontinuous; sutural fascia continuous, from which arises basal and subapical transverse stripes joining all fasciae; mesal fascia lighter in color; apical spot dark ( Fig. 3 a). Venter light brown.

Variation. Measurements of the body can vary total length 2.40–2.62 mm; maximum width 1.11–1.12 mm; maximum length of the head 0.26–0.38 mm; elytral length 1.02–1.86 mm; maximum width of the pronotum 0.96–1.02 mm. The elytral color pattern shows some variation in that some individuals have the fasciae and spots darkened.

Type material. Holotype 3, INPA (Coleop Holotipo INPA 305): Brasil, Amazonas, Jutaí, São Raimundo, Lago do Bosco, 06/09/2003, -2.68867, -66.87529, Nessimian J. L. & Hamada N. Paratypes, INPA (Coleop Paratipo INPA 305 [1–29]): 143 3Ƥ Brasil, Amazonas, Jutaí, São Raimundo, Lago do Bosco, 06/09/2003, - 2.68867, -66.87529, Nessimian J. L. & Hamada N.; 13 1Ƥ Brasil, Amazonas, Fonte Boa, Fonte Boa, Lago Ressaca Grande, 08/09/2003, -2.47399, -66.15474, Nessimian J. L. & Hamada N.; 83 2Ƥ Brasil, Amazonas, Tefé, São Francisco da Boca da Capivara, Barra do Solimões, 09/09/2003, -3.28228, -64.62169, Nessimian J. L. & Hamada N. DZRJ: ( Coleoptera 2821 ) 43 10Ƥ Brasil, Amazonas, Codajás, Urucurizinho, Lago Cuxuará, 15/09/2003, -3.97121, -61.96065, Nessimian J. L. & Hamada N.; ( Coleoptera 2822 ) 1Ƥ Brasil, Amazonas, Codajás, Urucurizinho, Igarapó, 15/09/2003, -3.96160, -61.95125, Nessimian J. L. & Hamada N.; ( Coleoptera 2823 ) 13 1Ƥ Brasil, Amazonas, Anamã, Boa Esperança, Lago Bom Jesus, 16/09/2003, -3.65812, -61.49109, Nessimian J. L. & Hamada N.; ( Coleoptera 2824 ) 1Ƥ Brasil, Amazonas, Manacapuru, Cristo Ressucitado, Lago Galo (Camoa), 17/09/2003, -3.57995, -60.82906, Nessimian J. L. & Hamada N.; ( Coleoptera 2825 ) 1Ƥ Brasil, Amazonas, Itacoatiara, Ilha da Trindade, Paraná da Trindade, 22/09/2003, -3.31345, -58.73231 Ferreira-Jr N. & de Marco P.

Etymology. The species is named for Dr. Paulo de Marco Junior, one of its collectors.

Taxonomic notes. See notes in B. nessimiani . Bidessodes demarcoi can be separated from other congeners by the combination of the following features: presence of a sutural longitudinal dark fascia, a sulcus on the last visible sternite, and the form of the male genitalia.

Figures

FIGURES 1 – 3. 1. Bidessodes nessimiani sp. nov. 2. Bidessodes hamadae sp. nov. 3. Bidessodes demarcoi sp. nov. a, Dorsal habitus; b, prosternal process, ventral view; c, last visible abdominal sternite; d, aedeagus and parameres, dorsal view; e, aedeagus and parameres, lateral view; f, aedeagus, lateral view. Scale in dorsal habitus = 1.0 mm, others = 0.5 mm.