Orinocotrichia angelus, De Souza, Wagner Rafael M., Santos, Allan Paulo Moreira & Takiya, Daniela Maeda, 2016

De Souza, Wagner Rafael M., Santos, Allan Paulo Moreira & Takiya, Daniela Maeda, 2016, Three new species of Stactobiinae (Trichoptera: Hydroptilidae) with the first record of Orinocotrichia Harris, Flint & Holzenthal from Brazil, Zootaxa 4078 (1), pp. 337-343 : 338

Orinocotrichia angelus sp. nov.

( Figures 1A–E )

Material examined. Holotype male. BRAZIL: Maranhão: Carolina, Parque Nacional da Chapada das Mesas, Riacho Cancela, Malaise trap, 07°06’43.4”S 47°17’16.6”W, 186 m a.s.l., 18–21.IX.2014, W.R.M. Souza & T.T. Andrade leg. ( CZMA). Paratypes. Same data as holotype, 3 males ( DZRJ), 1 male ( INPA).

Description. Holotype. Adult male. Length (from tip of the head to wing apex) 1.9 mm. General color pale yellow (in alcohol). Head without modification. Antennae simple; 18-articulated. Ocelli absent. Tibial spur formula 0-2-3. Fore- and hind wing venation reduced to basal veins. Mesoscutellum with transverse suture. Metascutellum rectangular, short, and wide. Abdomen without visible modifications. Segment VII without a mesoventral process. Male genitalia. Segment VIII annular. Segment IX reduced dorsally ( Fig. 1A ); sternum divided into 2 truncate lobes, curved laterad ( Fig. 1B ); posterolateral margin produced as a large rounded lobe and a sclerotized, elongate process ( Fig 1C ), curved inwardly in dorsal view ( Fig. 1A ); elongate apodemes originating from the anterolateral margin of segment, extending into segment VI ( Figs 1A–B ). Inferior appendages, in ventral view, short and rounded apically ( Fig. 1B ); in lateral view, subtriangular ( Fig. 1C ). Subgenital plate conspicuous and elongate; in ventral view completely divided into lateral arms, apex slightly darkened ( Fig. 1C ); in lateral view, digitiform ( Fig. 1B ). Tergum X membranous, subrectangular, elongate, and rounded apically in dorsal and lateral views ( Fig. 1C ). Phallus divided into 2 long branches, parallel basally, and strongly curved distally, with apices almost touching each other in ventral view ( Fig. 1D ); each arm bearing a dorsal curved retrorse spine-like process at apex ( Figs 1D–E ); ejaculatory duct protruding from the mesal incision of the phallus ( Fig. 1D ).

Etymology. The new species is named after Angelo B. M. Machado on the occasion of his 80th birthday (noun in apposition, nominative singular from classical form).

Remarks. This new species is the third species assigned to Orinocotrichia . Male genitalia structure of O. angelus sp. nov. is very similar to that of O. calcariga , particularly the posterolateral margin of segment IX produced into a large lobe and a sclerotized process, reduced inferior appendages, and phallus divided into 2 arms, each with an apical retrorse spine-like process. However, whereas O. calcariga and O. tagola have a reduced undivided subgenital plate, this structure in O. angelus sp. nov. is conspicuous, completely divided mesally, and more similar to that described for Flintiella species. Besides the subgenital plate, the new species can also be distinguished from its congeners by the truncate projections of sternum IX in ventral view, the broader lobe of the posterolateral margin of the same segment, and the phallus apical branches narrowing apically and almost touching each other in ventral view. Thus, males of Orinocotrichia can be distinguished from males of Flintiella based on the reduced inferior appendages and the more complex phallus apex. In fact, it is possible that Flintiella and Orinocotrichia are synonyms, but only a better knowledge of the diversity of Neotropical microcaddisflies and a formal phylogenetic analysis can help resolve this question.

Figures

FIGURES 1 A – E. Male genitalia of Orinocotrichia angelus sp. nov.: A. dorsal; B. ventral; C. left lateral; D. phallus, dorsal; E. phallus, lateral. Scale bar = 0.1 mm.