Acostatrichia plaumanni 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 : 208-209

Acostatrichia plaumanni Mosely 1939

Figs. 4–5 , 16

Acostatrichia plaumanni Mosely 1939: 228 , figs. 173–178, male; type locality: Brazil, Santa Catarina, Nova Teutonia; type depository: BMNH.

Angrisano (1995), reported from Uruguay.

Manzo et al. (2014), 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 = 10). General color, in alcohol, light brown. Head unmodified. Ocelli 3 ( Fig. 4A ). Antenna 19-articulated; scape cylindrical, twice as long as wide, inner margin not produced; pedicel cylindrical ( Fig. 4A ); flagellomeres cylindrical, unmodified. Forewings each with costal vein bearing short basal bulla ( Fig. 4B ). Abdominal segment VII bearing two acute ventromesal processes, basal one shorter ( Figs. 5A, 5E ).

Male genitalia. Segment VIII shorter dorsally than ventrally ( Fig. 5E ); in ventral view, posterior margin of sternum truncate, without lateral processes ( Fig. 5A ); tergum with scattered setae. Segment IX mostly within segment VIII, ventrally open; with pair of elongate dorsolateral processes, almost straight in ventral view ( Fig. 5A ); in dorsal ( Fig. 5B ) and lateral views ( Fig. 5C ), each one with very long and stout apical seta. Preanal process digitate, each bearing very long seta ( Fig. 5C ). Inferior appendages paired, short and triangular in ventral view ( Fig. 5A ); without apical or basal processes. Subgenital plate, in ventral view quadrangular ( Fig. 5A ); in lateral view triangular ( Fig. 5C ). Tergum X membranous, posterior margin convex in dorsal view ( Fig. 5B ); in lateral view slightly bilobed ( Fig. 5C ). Phallus tubular basally, bearing midlength complex, with dorsal window and basal loop shorter than basal portion of phallus; apical portion with plate-like sclerite and more than 8 internal spines.

Material examined. Brazil, Sta. Catarina, Nova Teutonia , i.1963, F. Plaumann, Flint det., 10 males ( NMNH); Brasilien, Nova Teutonia, 27°11’B 52°23’L, xi.63, Fritz Plaumann , Flint , 1975 det., 1 male ( NMNH). Uruguay, Artigas, Arroyo de la Invernada, 24.ii.1954, CS Carbonell leg., Flint 1982 det., 13 males ( NMNH); Tacuarembó, Puntas Arroyo Laureles, 10.ii.1954, CS Carbonell leg. Flint det., 16 males ( NMNH).

Remarks. Although the types were not examined, several specimens in the NMNH from the type locality and previously identified by Dr. Flint were studied. In addition, the illustrations and description provided by Mosely (1939) are with sufficient detail to recognize the species correctly. This species is the type species of the genus and in the phylogeny of Leucotrichiinae ( Santos et al. 2016) has been found in a distinct clade, referred to here as the A. plaumanni Group. In this group, Acostatrichia plaumanni , A. simulans , and A. fluminensis share the presence of preanal processes, each one with a very long seta; and the long and digitate dorsolateral processes on segment IX, each one with a stout spine ( Figs. 3C , 5C , 6C ). Acostatrichia plaumanni and A. simulans also share a short basal bulla on the costal vein of each forewing, absent in A. fluminensis . Acostatrichia plaumanni differs from these two and from other species in this group by the dorsolateral processes of segment IX ( Figs. 5A, 5B, 5C ), which are shorter, posteriorly directed, and almost straight (in A. simulans , they are curved inwards in ventral and dorsal views), and by the phallus bearing about 8 apical spines ( Figs. 5D, 5E ).

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

Figures

FIGURE 3. Acostatrichia fluminensis (Santos & Nessimian 2010), male paratype, genitalia. 3A, ventral; 3B, dorsal; 3C, left lateral; 3D, phallus, dorsal; 3E, phallus, left lateral. Abbreviations: sb. pl. = subgenital plate; inf. app. = inferior appendage (paired); dl. proc. = dorsolateral process of segment IX (paired); pre. proc. = preanal process; spat. scl. = spatulated sclerite. Scale bar = 0.1 mm.

FIGURE 4. Acostatrichia plaumanni Mosely 1939, non-type male from Santa Catarina, Brazil. 4A, head, dorsal; 4B, right forewing, dorsal. Scale bar = 0.2 mm.

FIGURE 5. Acostatrichia plaumanni Mosely 1939, non-type male from Santa Catarina, Brazil, genitalia. 5A, ventral; 5B, dorsal; 5C, left lateral; 5D, phallus, dorsal; 5E, phallus, left lateral. Abbreviations: sb. pl. = subgenital plate; pre. proc. = preanal process (paired); dl. proc. = dorsolateral process of segment IX (paired). Scale bar = 0.1 mm.

FIGURE 6. Acostatrichia simulans Mosely 1939, non-type male from Santa Catarina, Brazil, genitalia. 6A, ventral; 6B, dorsal; 6C, left lateral; 6D, phallus, dorsal; 6E, phallus, left lateral. Scale bar = 0.1 mm.

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.