Acostatrichia digitata Thomson & Holzenthal

Thomson, Robin E. & Holzenthal, Ralph W., 2012, New species and records of Hydroptilidae (Trichoptera) from Venezuela, ZooKeys 185, pp. 19-39 : 21

Acostatrichia digitata Thomson & Holzenthal sp. n. Fig. 1

Diagnosis.

This species is most similar to Acostatrichia fimbriata Flint, 1974 but can be distinguished by a mesoventral process on abdominal segment VII with an apex that is truncate and rugose, not pointed. The posterolateral process of abdominal segment VIII bears digitate projections apically, unlike the spines on Acostatrichia fimbriata . Additionally, the subgenital appendage of Acostatrichia digitatus is pointed apically instead of rounded.

Description.

Male. Length of forewing 2.7 mm (n=1). Head unmodified, with 3 ocelli; antennae unmodified. Tibial spur count 1, 3, 4. Dorsum of head dark brown with pale yellow setae; thorax dark brown with pale yellow setae dorsally, light brown ventrally; leg segments with light brown setae. Forewings covered with fine yellow setae and small scattered patches of dark brown setae. Genitalia. Abdominal sternum VII with long mesoventral process, apex truncate, rugose. Segment VIII anterolateral margin straight, posterolateral margin greatly elongate into narrow structure bearing digitate apical projections; ventrally posterior margin concave, mildly crenulated. Segment IX anterolateral margin acute, posterolateral margin broadly convex; with mesolateral quadrate structure bearing prominent setae (see Fig. 1A); dorsally with posterior margin straight. Subgenital appendage paired, broadly rounded with apicoventral point, dorsally with rounded emargination on inner edge. Inferior appendage setose, narrow, rod-like, fused latero-ventrally with subgenital appendage, in ventral view with semiquadrate apical emargination (see Fig. 1D). Tergum X membranous, triangular in dorsal view. Phallus tubular basally with median complex bearing basal loop and pair of circular “windows”, apex with pair of elliptic plates, strongly sclerotized mesolaterally.

Material examined.

Holotype male:VENEZUELA: Bolívar: E Tumeremo, W Bochinche, Río Botonamo, 07°25.462'N, 61°14.318'W, 150 m, 13.vii.2010, UV light, Holzenthal, Thomson, Cressa (UMSP000095201) (UMSP).

Etymology.

The Latin word digitatus meaning "having fingers",referring to the digitate projections on the posterolateral process of the VIIIth segment.