Acostatrichia fluminensis ( Santos & Nessimian 2010 )

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 : 205-208

Acostatrichia fluminensis ( Santos & Nessimian 2010)

Figs. 3 , 16

Costatrichia fluminensis Santos & Nessimian 2010: 840 , figs. 9–19, male, female; type locality: Brazil, Rio de Janeiro, Mangaratiba, Reserva Ecológica Rio das Pedras, 22°59’29.4”S 44°06’02.6”W; type depository: DZRJ.

Santos et al. (2016), phylogenetic placement in Acostatrichia .

Redescription. Length from front of head to tips of folded forewings 2.8–3.0 mm (n = 3). General color, in alcohol, brown. Head unmodified. Ocelli 3. Antenna 19-articulated; scape cylindrical, more than twice as long as wide, inner margin not produced; pedicel cylindrical; flagellomeres cylindrical, unmodified. Forewings each with costal vein simple, unmodified. Abdominal segment VII bearing two acute ventromesal processes, basal one shorter ( Figs. 3A, 3C ).

Male genitalia. Segment VIII shorter dorsally than ventrally ( Fig. 3C ); in ventral view, posterior margin of sternum very slightly emarginated ( Fig. 3A ), without lateral processes; tergum with scattered setae. Segment IX mostly within segment VIII, ventrally open; with pair of elongate dorsolateral processes, converging apically in dorsal view ( Fig. 3B ); downturned in lateral view ( Fig. 3C ), each one with very long apical seta. Preanal processes each digitate and bearing very long seta ( Fig. 3C ). Inferior appendages paired, short and triangular in ventral view, without apical or basal processes other than few setae ( Fig. 3A ). Subgenital plate, in ventral view, broad, with pointed and moresclerotized apex ( Fig. 3A ); in lateral view, triangular with pointed apex ( Fig. 3C ). Tergum X membranous, bilobed, quadrangular in dorsal view ( Fig. 3B ). Phallus tubular basally, bearing midlength complex with dorsal window and with basal loop indistinct; apical portion with spatulate sclerite ( Figs. 3D, 3E ).

Material examined. HOLOTYPE male: Brazil, Rio de Janeiro, Mangaratiba , Reserva Ecológica Rio das Pedras, 22°59’29”S 44°06’03”W, 23.v.2009, J.L. Nessimian, light trap ( DZRJ) ; PARATYPE: Brazil, Rio de Janeiro, Macaé, Córrego Duas Barras , 22°15’ 52°S 42°03’44”W, el. 217 m, 21.iii.2009, B.H.L. Sampaio, G.A. Jardim, I.C. Gonçalves, V. P. Alecrim, J.L. Nessimian, light trap, 1 male ( DZRJ).

Additional material: Brazil, Paraná, Morretes, afl. do Rio Nhundiaquara , 25°25’04”S 48°54’05”W el. 91 m, 23.i.2011, A.P.M. Santos, D.M. Takiya, J.L. Nessimian, L.L. Dumas, light trap, 1 male ( DZRJ).

Remarks. This species was originally described in Costatrichia , but other than the absence of a bulla in the costal vein of each forewing, it presents the features of the A. plaumanni Group, such as segment VII with a double ventromesal process ( Fig. 3A ), a pair of long dorsolateral processes on segment IX ( Fig. 3C ), and the inferior appendages short and not fused mesally ( Fig. 3A ). The species has been transferred to Acostatrichia by Santos et al. (2016) based on phylogenetic studies, which indicated that both morphology and molecular data supported a close relationship between A. fluminensis and A. simulans ( Santos et al. 2016) . Santos & Nessimian (2010) also mentioned the absence of a subgenital plate in the original description, but the paratype and the additional specimen observed, which agree in all other aspects with the holotype, clearer present this structure. Acostatrichia fluminensis shares with A. plaumanni and A. simulans the similar general aspect of male genitalia, particularly the long and digitate pair of dorsolateral processes of segment IX, the presence of short preanal processes, each one with a long apical seta, and short and triangular inferior appendages. This species can be distinguished from these other two and from others in the A. plaumanni Group due to the dorsolateral processes of segment IX being strongly curved downward in lateral view ( Fig. 3C ), and the phallus having an apical spatulated sclerite ( Fig. 3D ).

Distribution. Brazil ( 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 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.