Smicridea (Rhyacophylax) bicornuta, Albino, Jeyson Lazaro Duque, Pes, Ana Maria & Hamada, Neusa, 2011

Albino, Jeyson Lazaro Duque, Pes, Ana Maria & Hamada, Neusa, 2011, Smicridea (Trichoptera, Hydropsychidae) from 3 Brazilian Amazonian States: New species, larval taxonomy and bionomics, Zootaxa 3113, pp. 1-35 : 5-7

Smicridea (Rhyacophylax) bicornuta sp. nov.

Figs 6–12

Adult male. Forewing length 4.7–4.81 mm (n = 3). General color in alcohol yellowish-brown. Head and thorax dorsally grayish. Forewings yellowish-brown, each with dark stain along transverse veins, costal margin and pterostigma with brown band, nigma and thyridial brown; apical region with less-distinct whitish-brown band ( Fig. 6 ). Anterolateral glandular processes of sternum V slender, with length (0.92 mm) 4 times longer than length of this segment ( Fig. 7 ).

Male genitalia. Segment IX in dorsal view with posterodorsal margin projected, triangular, bearing many small spikes; anterodorsal margin excised, forming rounded angle ( Fig. 9 ). Tergum X triangular, tapered to blunt apex, ventrolateral margins well sclerotized in lateral view ( Fig. 8 ); divided on meson 2/3 its length, forming caudal projections each with rounded, setose distal region in dorsal view ( Fig. 9 ). Inferior appendages 2-segmented, basal segment long, its distal region elongated and enlarged, covered with long setae; distal segment short, 1/3 as long as basal segment, its apex blunt ( Fig. 9 ). Phallus with tubular phallobase, its basal section enlarged, forming angle of approximately 100o with middle section and of approximately 110° with distal section ( Fig. 8 ). Internal sclerotized portion of ejaculatory duct, in lateral view, short (¼ phallus length), divided in 2 distally and enlarged, resulting in scissors shape ( Fig. 8 ); extruded endothecal membranes with pair of lateral sclerotized processes resembling small horns ( Figs 8, 12 ), these processes surrounding apex of internal sclerotized portion of ejaculatory duct when retracted ( Figs 10–11 ); dorsal periphallic membranes absent.

Female and immatures. Unknown.

Diagnosis. The male of S. bicornuta sp. nov. differs from those of other described species in the subgenus by having the internal sclerotized distal region of the ejaculatory duct of the phallus diverging distally, in scissors shape, and with subapicolateral sclerotinized paramere spines short. The male is similar to those of S. appendiculata , S. flinti sp. nov., S. mangaratiba Almeida & Flint 2002 , S. roraimense sp. nov. and S. voluta Flint 1978 by having the phallus with a short internal sclerotized apical portion of the ejaculatory duct divided in 2 parts distally.

Biology: Adults of S. bicornuta sp. nov. were collected with light traps placed over streams 4.7 m in width and located in an area of preserved gallery forest in the Cerrado biome.

Distribution. Brazil, Mato Grosso State.

Etymology. The name bicornuta (Latin, bi = 2 and cornus = horns), refers to the 2 horn-shaped processes on the subapicolateral regions of the phallus in dorsal view.

Material examined. Holotype male: BRAZIL, Mato Grosso, Nova Xavantina municipality, Córrego da Mata (4th order stretch), S 15º01'32" W 52º26' 29, 17.ix.2005, H.S.R. Cabette, light trap with mercury lamp over white cloth, 1 male [alcohol] ( INPA). Paratypes: BRAZIL, Mato Grosso, Nova Xavantina, Córrego da (4th order stretch), S 15º01'32" W 52º26' 29, 17.ix.2005, H.S.R. Cabette, light trap with mercury lamp over white cloth, 15 males [alcohol] ( INPA); 1 male [alcohol] (UNEMAT); 1 male [alcohol] ( MZUSP).

Figures

FIGURES 6 – 7. Smicridea (Rhyacophylax) bicornuta sp. nov. 6) Male right forewing, dorsal view, scale bar = 500 µ; 7) sternum V, ventral view, showing anterolateral glandular processes, scale bar = 200 µ.

FIGURES 8 – 12. Smicridea (Rhyacophylax) bicornuta sp. nov. male genitalia. 8) Left lateral view; 9) dorsal view; 10) phallus retracted, dorsal view; 11) phallus retracted, left lateral view; 12) phallus expanded, dorsal view.