Oxyethira (Tanytrichia)

De Souza, Wagner Rafael M. & Santos, Allan Paulo Moreira, 2017, Taxonomic study of the genus Oxyethira Eaton 1873 (Trichoptera: Hydroptilidae) from Northeast Brazil: Eleven new species and distributional records, Zootaxa 4236 (3), pp. 484-506 : 500-503

Oxyethira (Tanytrichia) una

Fig. 11A–11 D

Description. Holotype. Length 2.0 mm. General color pale brown (in alcohol). General pattern of Neotropical Oxyethira . Sternum VII with posterior mesoventral process ( Fig. 11A ).

Male genitalia: Segment VIII annular, covered with setae; sternum VIII completely divided longitudinally, posterolateral margins widely separated and narrowing to apices ( Fig. 11A ); tergum VIII with deep median incision, wide and divergent posteriorly, narrow anteriorly, almost reaching anterior margin of segment ( Fig. 11 B). Segment IX retracted in segment VIII, sternum IX produced anteriorly into middle area of segment IV, with anterior margin truncate ( Figs. 11A, 11 B); in lateral view, produced into dorsal process inside segments VII and VIII, abruptly angled about 90° subapically, directed posterad ( Fig. 11 C); tergum reduced. Inferior appendages short, apices darkened ( Fig. 11A ); fused to the segment IX basally and to each other, straight, digitiform apically ( Fig. 11A ); in lateral view, narrowing to apex ( Fig. 11 C). Subgenital plate conspicuous, produced into elongate, tapered medial process dorsally, about as long as inferior appendages; in ventral view, with two round anterolateral lobes basally; in dorsal view, medial process covering anterolateral lobes. Bilobed process with pair of elongate, slender processes, each with small apical seta ( Fig. 11 B). Tergum X membranous. Phallus simple, slender, and sinuous, without spines or processes; ejaculatory duct indistinguishable ( Fig. 11 D).

Remarks. Although most similar to other Tanytrichia species due to the elongate sternum IX, reaching into segment IV, the new species lacks the lateral processes of the phallus. Oxyethira una sp. nov. has the phallus simple, sinuous, without spines or processes. Among the species in this subgenus, the new species is most similar to O. paritentaculata Kelley 1983 and O. colombiensis Kelley 1983 in that these species also have segment IX projecting dorsad and abruptly bent caudad in lateral view. Oxyethira una sp. nov. can be identified by the subgenital plate bearing an elongate process with a digitiform apex and by the simple structure of the phallus.

Etymology. The specific name is given in reference to the type-locality.

Material examined. Holotype. BRAZIL: Bahia: Una, Reserva Biológica de Una riacho de 1ª ordem após a fazenda Piedade , 15°09'36''S, 39°10'31''W, 14.vi.2014, APM Santos, DM Takiya, AC Domahovski, AP Pinto & WRM Souza cols., light trap, 1 ♂ ( DZRJ).

Figures

FIGURE 11 A – 11 D. Oxyethira una sp. nov. Male genitalia: 11 A, ventral; 11 B, dorsal; 11 C, left lateral; 11 D, phallus, dorsal.