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

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

( Fig. 2 )

Diagnosis. Elytra dark brown with lighter spot at apex ( Fig. 2 a). Prosternal process with lateral margins convex and apex acuminate ( Fig. 2 b). Middle tibiae curved in males. Last visible sternite with sulcus near apex ( Fig. 2 c). Aedeagus in dorsal view narrower at middle, in lateral view slightly curved ( Figs 2 d–f). Parameres in dorsal view curved; segments separated by circular membranous area; apex triangular, with row of bristles ( Figs 2 d, e).

Description. Holotype male: total length 2.62 mm; maximum width 1.12 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. 2 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 convex and apex acuminate ( Fig. 2 b). Legs with three basal tarsomeres expanded on fore and middle tarsi; middle tibiae curved near base; 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 ( Fig. 2 c). Aedeagus in dorsal view narrower at middle, in lateral view slightly curved ( Figs 2 d–f). Parameres in dorsal view curved, forming angle of 45 degrees; segments separated by circular membranous area; apex triangular with row of bristles ( Figs 2 d, e).

Coloration. Head, pronotum and venter reddish brown. Elytra dark brown, with lighter apical spot ( Fig. 2 a).

Variation. The size of the body does not vary at perceivable way. Measurements of the body can vary in total length 2.62–2.70 mm; maximum width 1.10–1.25 mm; maximum length of the head not vary; elytral length 1.90–2.00 mm; maximum width of pronotum 1.00– 1.10 mm. Females have middle tibiae straight.

Type material. Holotype 3, INPA (Coleop Holotipo INPA 304): 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 304 [1–5]): 23 3Ƥ Brasil, Amazonas, Jutaí, São Raimundo, Lago do Bosco, 06/09/2003, - 2.68867, -66.87529, Nessimian J. L. & Hamada N. DZRJ: ( Coleoptera 2820 ) 13 2Ƥ Brasil, Amazonas, Fonte Boa, Fonte Boa, Lago Ressaca Grande, 08/09/2003, -2.47399, -66.15474, Nessimian J. L. & Hamada N.

Etymology. The species is named for Dr. Neusa Hamada, one of its collectors.

Taxonomic notes. The nearly uniform coloration of B. hamadae sp. nov. is uncommon among Bidessodes species. Based on the color pattern, the new species can only be confused with B. acharistus or highly sclerotized specimens of other species with an obscure pattern of fasciae and spots. However, B. hamadae can be distinguished by presence of a sulcus on the last visible sternite, and by 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.