Buenoa exilidens Barbosa, Nessimian & Ferreira-Keppler

Barbosa, Julianna Freires, Nessimian, Jorge Luiz & Ferreira-Keppler, Ruth Leila, 2010, Two new species of Buenoa Kirkaldy, 1904 (Hemiptera: Heteroptera: Notonectidae) from the States of Amazonas and Roraima, Brazil, Zootaxa 2565, pp. 49-54 : 52-53

Buenoa exilidens Barbosa, Nessimian & Ferreira-Keppler sp. nov.

(Fig. 6–8)

Type material. BRAZIL, State of Amazonas, Barcelos Municipality, Serra do Aracá, base, Igarapé da Anta, alt. 152m [00,87913ºN / 63,45395ºW], poça em rocha (laje), 03.VIII.2009 (U. G. Neiss): 1m macropterous, holotype ( INPA). Paratype: idem holotype, 1m macropterous ( INPA).

Description of holotype. Measurements (male). Body length: 5.90; vertex: 0.21; synthlipsis: 0,07; head length: 0.52; head width: 1.47; pronotum length: 0.80; pronotum width: 1.60; scutellum length: 1.05; scutellum width: 1.27; length of fore femur: 0.87; width of fore femur: 0.22.

Color. General facies dark brown. Head yellowish. Base of tylus, labrum, ventral surface of third and fourth rostral segments dark brown. Central area of pronotum brown and lateral areas yellowish; lateroventral surface of pronotum brown. Scutellum brown with third posterior yellow. Base of hemelytra and posterior wings orange; anterior region hyaline; posterior third of hemelytra brown. Dorsal region of body dark brown. Ventral region of thorax yellow and legs yellowish; hind coxa light brown. Abdomen brown; connexivum yellow.

Head. Greatest width of head seven times anterior width of vertex and narrower than greatest width of pronotum; head length at median line two-thirds length of pronotum. Anterior margin of vertex continuous with the margin of eyes. Synthlipsis narrow, about one-third of vertex width. Frons narrow with parallel margins. Tylus inflated. Rostral prong slender, much longer than third rostral segment, with base originating at distal region of this segment, protruding anteriorly at the base and apex slightly rounded (Fig. 6).

Thorax. Pronotum with only a faint median carina; lateral margins divergent; posterior margin slightly concave medially; median length one-half of its width. Scutellum large with median length greater than that of pronotum. Apex of fore femur wide, with the length more than three times width; stridulatory area triangular with seven prominent and irregular ridges (Fig. 7). Fore tibia with 35 stridulatory teeth of similar size. Hind femur with 27 setae at internal margin.

Abdomen. Hook of left clasper with apex acute and turned anteriorly. Apex of right clasper rounded and obtuse (Fig. 8).

Paratype. Measurements (male). Body length: 5.50; vertex: 0.20; synthlipsis: 0.07; head length: 0.52; head width: 1.40; pronotum length: 0.82; pronotum width: 1.52; scutellum length: 0.92; scutellum width: 1.32; length of fore femur: 0.85; width of fore femur: 0.22.

Most parts of pronotum yellowish and posterior region brown. Ventral surface of abdomen light brown. Head length at median line about five-eighths the length of pronotum. Length of pronotum at median line slightly longer than one-half of its width. Stridulatory area of fore femur with four irregular and prominent ridges; fore tibia with 38 stridulatory teeth. Hind femur with 32 setae at internal margin.

Etymology. The species epithet, exilidens , refers to the rostral prong conspicuously slender, from the Latin dens = tooth and exilis = slender.

Comments. Using the key for identification of Truxal (1953), this species can be identified as B. mutabilis Truxal, 1953 . The body length of both species is similar, both have a narrow synthlipsis, about onethird of the width of vertex; pronotum not tricarinate; length of fore femur more than three times its width and less than 40 setae at internal margin of hind femur. Buenoa exilidens sp. nov. can be recognized by its head length seven times width of vertex, rostral prong protruding at distal region of third rostral segment, and stridulatory area of fore femur triangular with a maximum of seven ridges. Buenoa mutabilis has a head length six and one-half times width of vertex, rostral prong protruding at median region of third rostral segment, and stridulatory area of fore femur subtriangular with 10 to 18 ridges. The general appearance of its body resembles B. platycnemis (Fieber, 1851) with a dark brown color and rostral prong originating laterally at distal region of third rostral segment, distinctly longer than this segment. The rostral prong of B. exilidens sp nov. is visibly more slender than that of B. platycnemis ; the pronotum is not tricarinate; the apex of fore femur is narrower; the stridulatory area presents four to seven irregular ridges; and the claspers are distinct. The pronotum of Buenoa platycnemis is distinctly tricarinate; the stridulatory area has 11 to 14 well-marked ridges. The rostral prong of B. exilidens sp. nov. is similar to that of B. tumaquensis Padilla-Gil, 2010 , but is more slender than that. The fore femur of B. exilidens sp. nov. lacks the parallel striae perpendicular to the comb, has fewer ridges at the stridulatory area and less stridulatory teeth at the fore tibia than does B. tumaquensis .