Polycentropus cressae Hamilton and Holzenthal, new species

Fig. 1

Polycentropus cressae n. sp. is similar to P. a z t e c u s, P. gertschi and P. neblinensis n. sp. in the possession of a single pair of anterior spines in the phallic membranes below the phallic sclerite (Fig. 1 E & F) in addition to another more mesal group of spines. In P. cressae and P. neblinensis, the anterior (basal) pair of spines is large and reminiscent of bull’s horns. In P. cressae, the spines in the mesal group (Fig. 1 E & F) are less numerous (35– 40) and larger than those in P. neblinensis (>50). Polycentropus aztecus and P. gertschi have a single pair of spines in the anterior group that are notably smaller and more similar to those in the mesal group and those in the mesal group are 4 and 6 in number, respectively.

Polycentropus cressae is unique in the number of heavier mesal spines in the phallic membranes (ca. 35–40; Fig. 1 E & F), the lateral flanges on the posterior margins of the phallobase (Fig. 1 E), the narrow ventromesal process of the phallobase with a shallow apical emargination (Fig. 1 E & F), the narrow lateral face of the inferior appendage (Fig. 1 A), and the simple triangular shape of the preanal appendage in lateral view (Fig. 1 A).

Adult. Length of forewing: male 6.5–7.0 mm (n=3), female 7.5–8.2 mm (n=2). Body pale brown to yellow, legs stramineous, dorsum of head and thorax brown, clothed with long, dark setae; general vestiture of forewing with fine, brown to dark brown setae, with many scattered areas of golden setae, base of forewing with long, erect setae.

Male. Genitalia as in Fig. 1. Sternum IX in lateral view subtriangular, in ventral view quadrate; anterior margin shallowly concave, posterior margin slightly produced medially. Tergum IX and X membranous. Intermediate appendage straight, slightly angled basally, short, exceeding preanal appendage by less than 1/4th its length; basal region simple, not expanded; apex digitate, with apical setae. Preanal appendage short, densely setose, triangular, broad basally; mesoventral process absent. Inferior appendage densely setose, short, subtriangular, wide dorsoventrally, subequal to length; dorsolateral flange narrowly rounded; ventrally with dorsally­directed caudomesal point, exposed in lateral view; in ventral view, inferior appendage subtriangular, caudomesal point prominent, acute; in caudal view, inferior appendage subtriangular, caudomesal point broadly triangular. Phallobase very short, apicolateral corner produced into short flange; apicoventral projection long, narrow, with pair of points; phallic membranes with anterior and mesal groups of spines (although probably reversed in evaginated phallus), anterior group consisting of long, paired, curved spines, mesal group of many (35–40) small spines; phallic sclerite oval (difficult to discern, especially apically). Subphallic sclerite U­shaped in caudal view.

Holotype male. VENEZUELA: Falcón: P[arque]. N[acional]. Sierra de San Luis, Río Negro, 11º11.750'N, 69º41.454'W, el. 1371 m, 8–9.vi.2001, Holzenthal, Blahnik, Paprocki, Cressa (UMSP 000074848) (UMSP)

Paratypes: Same data as holotype— 1 male, 1 female (UMSP), 1 male, 1 female (NMNH).

Etymology. We take great pleasure in naming this species in honor of Dr. Claudia Cressa, Universidad Central de Venezuela, in recognition of her contributions to the study of Venezuelan aquatic insects and her generous support of our work in Venezuela.