Alisotrichia cainguas Angrisano & Sganga

Angrisano, Elisa B. & Sganga, Julieta V., 2009, New species of Hydroptilidae (Trichoptera) from Salto Encantado Provincial Park (Misiones province, Argentina), Zootaxa 2162, pp. 57-68 : 58-60

Alisotrichia cainguas Angrisano & Sganga , new species

Figures 1–8 , 31, 36

Male. Forewing length 1.6 mm. Coloration of the body (in alcohol) homogeneous light grayish brown. Head wider than long ( Fig. 1 ). Two ocelli. Antennae 18-segmented; scape wider and longer than the other antennal segments. Fourth segment of the maxillary palp oval, wider than the others, 5th thin and longer than the 4th ( Fig. 2 ).

Abdominal segments lightly sclerotized, except sterna VII and VIII, especially the latter, that is dark grayish brown, contrasting with the coloration of the other segments, very evident in specimens not cleared ( Fig. 31 ). Sternum VII with a bifid spine. Segment VIII sclerotized ventrally, partially membranous dorsally; posterior end with a wide apical cleft, U-shaped, in ventral view ( Fig. 3 ); lateroposterior margin with 2 points, the ventral one longer ( Fig. 4 ); mesally, in dorsal view, with a pair of projections directed to the midline that bear the insertions of wide, thick setae at the tip (loose from the base in the type); next to both insertions there is a thin seta ( Fig. 5 ). Segment IX flattened, placed inside segment VIII; sclerotized dorsally, open ventrally; with long anterior apodemes (according to Harris & Flint 2002, these apodemes belong to segment X) ( Fig. 6 ); distally, with a pair of arched projections that lay underneath the phallus (ventral to segment X, incomplete at the midline?), and long lateral setae (between the anal cone and segment VIII in figure 5); with a curled tubular ventral structure (spiral process); between the anal cone and the spiral process there is a long, thin spine ( Fig. 7 ). Phallus short, without spines or any particular processes ( Fig. 8 ). Anal cone wide, membranous ( Figs. 5–7 ).

Diagnosis. This species belongs to the A. orophila group (defined according to Harris and Holzenthal 1993) that contains 18 species characterized by a dorsolateral process of segment VIII that bears a large, long, and very conspicuous seta, which is considered a synapomorphy of the group. This is the 2nd species of Alisotrichia recorded from Argentina, and until now the most austral of the genus.

The closest related species are differentiated from A. cainguas , new species mainly by the following characters: 1) Without a bifid spine in sternite VII in A. cacaulandia Harris & Flint 2002 , A. kanukua Harris & Flint 2002 , and A. neblina Harris & Flint 2002 . 2) The lateroposterior margin of segment VIII is truncated in A. woldai Harris & Flint 2002 , lightly produced posterodorsally in A. cacaulandia , rounded in A. kanukua , A. neblina and A. gabriel Angrisano 2002 , tapered in A. paxilla Harris & Flint 2002 , and laterally excavated in A. mathisi Harris & Flint 2002 . 3) The curled tubular ventral structure of segment IX is only present, besides the new species, in A. cacaulandia , A. kanukua , and A. woldai , being tubular in the other species. This structure is also found in species from other groups. 4) The structure of the phallus is clearly different in all the species of the genus. 5) Several species, especially the ones from Central America, bear spines or thick, conspicuous setae in the posterior margin of segment VIII, which are absent in the new species.

Holotype male. Misiones: Parque Provincial Salto Encantado, tributary of Arroyo Cuñá-Pirú, Malaise trap, 8–14.i.2006, Angrisano & Bravo leg.

Paratypes. Argentina: Misiones: Parque Provincial Salto Encantado, 10–13.iii.2008, Angrisano & Sganga leg., 1 male.

Etymology. Named for the department of Cainguas where part of Salto Encantado Provincial Park is located.

Figures

FIGURES 1 – 12. Figs. 1 – 8, Alisotrichia cainguas, n. sp.: 1: Head, dorsal view. 2: Maxillary palp. Figs. 3 – 5, abdominal segment VIII: 3: ventral. 4: lateral. 5: abdominal segments VIII – X, dorsal. Figs. 6 – 7: abdominal segment IX: 6: lateral. 7: ventral. 8: phallus. Figs. 9 – 12, Metrichia pitu, n. sp., male genitalia: 9: lateral. 10: ventral. 11: dorsal. 12: phallus.

FIGURES 31 – 43. Figs. 31, 36, Alisotrichia cainguas, n. sp.: 31: adult, lateral. 36: male genitalia. Figs. 32, 37, Ochrotrichia pora, n. sp.: 32: adult, ventral. 37: male genitalia. Figs. 33, 38, Paratrichia acuti, n. sp.: 33: adult, lateral. 38: male genitalia. Figs. 34, 40, Rhyacopsyche garuhape, n. sp.: 34: adult, ventral. 40: male genitalia. Figs. 35, 39, 41, Oxyethira tamandua, n. sp.: 35: adult, ventral. 39: male genitalia, dorsal. 41: male genitalia, lateral. Figs. 42, 43, Oxyethira poapi, n. sp., male genitalia: 42: lateral. 43: phallus apex, detail.