Acostatrichia 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 : 202-204

Acostatrichia Mosely 1939

urn:lsid:zoobank.org:act:A2AFDE14-33A0-4061-A934-7B0EA79ECBC5

Acostatrichia Mosely 1939: 228 . Type species: Acostatrichia plaumanni Mosely 1939 , original designation.

Flint (1970), included in Leucotrichiinae .

Marshall (1979), reviewed; in Leucotrichiini .

Angrisano & Sganga (2010), immature stages.

Oláh & Johanson (2011), morphological characters.

Oláh & Flint (2012), morphological characters.

Santos et al. (2016), phylogeny; in Leucotrichiini .

Holzenthal & Calor (2017), catalog.

Redescription. Male. Length from front of head to tips of folded forewings: 2.0– 4.5 mm. General color, light brown or brown, usually with spots of green setae on head, thorax, and wings. Head usually unmodified; when modifications present, with membranous protuberances, covered by setae. Ocelli 2 or 3. Antenna 19–21 articulated, scape cylindrical; pedicel cylindrical; flagellomeres cylindrical, unmodified. Forewings each with costal vein unmodified or bearing short basal bulla. Abdominal segment VII bearing one or two ventromesal processes.

Male genitalia. Segment VIII shorter dorsally than ventrally. Segment IX mostly within segment VIII, ventrally open, with or without posterior processes. Preanal process present or absent. Inferior appendages short and paired or fused to each other basally or fused to each other completely as a conspicuous plate. Subgenital plate present and broad. Tergum X membranous, simple or bilobed. Phallus tubular basally, bearing midlength complex, with dorsal window and basal loop; apical portion with or without spines and sclerites.

Distribution. Argentina, Brazil, Ecuador, French Guiana, Peru, Suriname, Uruguay, and Venezuela ( Fig. 16 ).

Remarks. As indicated by Santos et al. (2016), Acostatrichia probably is not a monophyletic group, but the relationships of species included in this genus remain uncertain. Currently, adult males of Acostatrichia can be distinguished from those of other Leucotrichiini genera by the combination of the following features: (1) antennal articles are simple, with the scape usually twice as long as wide; (2) each forewing costal vein is simple or bears a short bulla (not reflexed); (3) abdominal segment VII has a long ventromesal process or has two ventromesal processes; (4) abdominal segment VIII or IX bears paired posterior processes.

Here, Acostatrichia species are divided into three species groups: The A. plaumanni Group (including the type species), the A. brevipenis Group, and the A. cerna Group. These groups are defined based on a combination of morphological features as an attempt to understand better the diversity in this genus. The characteristics chosen here to distinguish the species groups are based on the morphological characters provided by Santos et al. (2016) and also on the re-examination of Acostatrichia specimens. Even so, some species are still difficult to allocate, since they do not necessarily have all defining features of their groups.

Figures

FIGURE 16. Distribution map of the Acostatrichia species in South America, based on material examined here and previously published records. When latitude and longitude were not available, an approximate location was used. Circle, species in the Acostatrichia plaumanni Group; square, species in the Acostatrichia brevipenis Group; triangle, species in the Acostatrichia cerna Group.