Leucotrichia bicornuta Thomson, 2012

Thomson, Robin E. & Holzenthal, Ralph W., 2015, A revision of the Neotropical caddisfly genus Leucotrichia Mosely, 1934 (Hydroptilidae, Leucotrichiinae), ZooKeys 499, pp. 1-100: 10-11

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Leucotrichia bicornuta Thomson, 2012


Taxon classification Animalia Trichoptera Hydroptilidae

Leucotrichia bicornuta Thomson, 2012   Fig. 9

bicornuta   Thomson, 2012: 4 [Type locality: Brazil, Río de Janeiro, Panedo, Río das Pedras, Três Bacias; DZRJ; male].


This species is similar to Leucotrichia dianeae   sp. n., Leucotrichia extraordinaria   , and Leucotrichia tapantia   sp. n. In each of these species, the posterolateral margin of sternum VIII is produced, with the apex of the projection bearing either prominent setae or a peg-like seta. The shape of the phallus apex is also similar in all these species, with all bearing a pair of membranous apical lobes and lacking any external spines or sclerites. Leucotrichia bicornuta   differs from the other 3 species in having fused inferior appendages and a distinct, irregularly shaped dorsal arm on the subgenital plate.


Male. Length of forewing 2.5-3.4 mm (n=3). Head unmodified, with 3 ocelli; antennae unmodified. Color in alcohol brown. Genitalia. Abdominal sternum VII with digitate mesoventral process with small basal ridge. Sternum VIII posteromesal projection bearing long, prominent setae; in ventral view with posterior margin concave. Segment IX anterolateral margin broadly produced dorsolaterally, posterolateral margin irregular; in dorsal view anterior margin convex, posterior margin concave. Tergum × with dorsal sclerite slender; ventral sclerite semielliptic with tridentate posterior margin; membranous apex suborbicular. Subgenital plate with dorsal arm irregular, bent sharply dorsad (Fig. 9A); ventral arm short, digitate, with basal projection, laterally obscured from view by inferior appendage (Fig. 9A), in ventral view with rounded apical emargination. Inferior appendage arched mesally, apex hooked dorsally, bearing single dorsal spine; in ventral view entirely fused, apex emarginated. Phallus apex bearing paired apicodorsal lobes, no spines or sclerites apparent.

Material examined.

Holotype male: BRAZIL: Río de Janeiro: Panedo, Río das Pedras, Três Bacias, 22°24'32.2"S, 44°33'06.6"W, elev. 735 m, 6.iii.2008, Nessimian, Dumas, de Souza, and Braga (in alcohol) (UMSP000014084) (DZRJ). Paratypes: BRAZIL: Río de Janeiro: Itatiaia, Parque Nacional do Itatiaia, Río Camp Belo, 22°27'17.32"S, 44°36'37.47"W, elev. 705 m, 13.iv.2007, light, Santos, Dumas, Ferreira, Jr., and Nessimian, 2 males, 1 female (in alcohol) (DZRJ).


Bi, Latin for “double”; cornutus, Latin for “horned”, referring to the 2 apicodorsal lobes of the phallus.