Acostatrichia simulans Mosely, 1939

Santos, Allan Paulo Moreira, 2020, A review of the Neotropical microcaddisfly genus Acostatrichia Mosely, 1939 with description of a new species from Brazil (Trichoptera: Hydroptilidae: Leucotrichiinae), Zootaxa 4755 (2), pp. 201-230 : 209-210

Acostatrichia simulans Mosely, 1939

Figs. 6, 16

Acostatrichia simulans Mosely 1939: 229 , figs. 179–182, male; type locality: Brazil, Santa Catarina, Nova Teutonia; type depository: BMNH.

Angrisano (1995), reported from Uruguay.

Angrisano & Sganga (2010), larva, pupa, case, biology, reported from Argentina.

Santos et al. (2016), phylogenetic placement.

Redescription. Length from front of head to tips of folded forewings 2.0–3.0 mm (n = 9). General color, in alcohol, light brown. Head unmodified. Ocelli 3. Antenna 19-articulated; scape cylindrical, twice as long as wide, inner margin not produced; pedicel cylindrical; flagellomeres cylindrical, unmodified. Forewings each with costal vein bearing short basal bulla. Abdominal segment VII bearing two acute ventromesal processes, basal one shorter ( Figs. 6A, 6C).

Male genitalia. Segment VIII shorter dorsally than ventrally ( Fig. 6C); in ventral view, posterior margin of sternum with shallow median V-shaped incision ( Fig. 6A), without lateral processes; tergum with scattered setae. Segment IX mostly within segment VIII, ventrally open; with pair of elongate dorsolateral processes, gradually curved inwards in dorsal and ventral views ( Figs. 6A, 6B), almost straight in lateral view ( Fig. 6C), each one with sinuous subapical spine ( Figs. 6A, 6B, 6C). Preanal processes digitate and each bearing very long seta ( Fig. 6C). Inferior appendages paired, short and triangular in ventral view, without apical or basal processes ( Fig. 6A). Subgenital plate, in ventral view broad and concave at apex ( Fig. 6A); in lateral view, triangular ( Fig. 6C). Tergum X membranous, posterior margin convex in dorsal view ( Fig. 6B), slightly bilobed in lateral view ( Fig. 6C). Phallus tubular basally, bearing midlength complex with dorsal window and basal loop shorter than basal portion of phallus; apical portion with Y-shaped sclerite and internal spine ( Figs. 6D, 6E).

Material examined. Brazil, Santa Catarina, Nova Teutonia, ix.1963, F Plaumann leg., Flint 1975 det., 1 male ( NMNH); Nova Teutonia, i.1963, F. Plaumann, Flint det., 6 males ( NMNH). Argentina, Província Misiones, Salto Encantado Provincial Park, Arroyo Azul , 23-28.i.2008, Angrisano & Sganga leg., Sganga 2012 det., 1 male ( DZRJ). Uruguay, Artigas, Rio Cuareim, Sepulturas , 15.xii.1952, CS Carbonell , Flint det., 1 male ( NMNH).

Remarks. Acostatrichia simulans shows typical features of the A. plaumanni Species Group, such as the following: (1) a costal bulla in each forewing, (2) a double ventromesal process on segment VII, (3) the inferior appendages short and not fused to each other, and (4) a pair of long dorsolateral processes on segment IX. In the A. plaumanni Group, A. simulans shares more similarities in male genitalia with A. plaumanni and A. fluminensis , but it can be distinguished from those by a shallow median incision on the posterior margin of segment VIII in ventral view ( Fig. 6A); and by the dorsolateral processes of segment IX curved inwards in ventral and dorsal views, each one with a short sinuous subapical spine ( Figs. 6A, 6B). This is the only Acostatrichia species with immature stages described ( Angrisano & Sganga 2010). According to Angrisano & Sganga (2010), the larva is similar to those described for other Leucotrichiini genera, in particular to larvae of Zumatrichia Mosely 1937 , but the A. simulans larva differs by having the frontoclypeus with a reticulate sculpturing and each tarsal claw with an enlarged basal seta.

Distribution. Argentina, Brazil, and Uruguay ( Fig. 16).