Chimarrhodella choco, Holzenthal, Ralph W., Blahnik, Roger J. & Rios-Touma, Blanca, 2018

Holzenthal, Ralph W., Blahnik, Roger J. & Rios-Touma, Blanca, 2018, New species and a new genus of Philopotamidae from the Andes of Bolivia and Ecuador (Insecta, Trichoptera), ZooKeys 780, pp. 89-108 : 89

Chimarrhodella choco sp. n. Figs 4, 5

Diagnosis.

This new species is distinctive. Especially diagnostic is the coloration, with yellowish head and thorax and brown wings; also diagnostic are the relatively short curved inferior appendages and the characteristic shape of tergum X. The general structure of the inferior appendages, with acute apices, is like that of C. costaricensis and species of the peruviana group. The linear row of bristle-like setae on the inferior appendage found in the new species, generally characterizes species in both the galeata and peruviana groups, but apparently not C. ornata Blahnik. However, like C. ornata , C. choco has short preanal appendages and a pale testaceous or yellowish head and thorax. Also it has a relatively simple phallic structure, without the highly pleated endotheca and pleated dorsal expansion that characterizes other species. The short female genitalia resemble those of species in the galeata group.

Description.

Adult. Forewing length (male) 5.7-6.7 mm (n = 9); (female) 6.1-7.0 (n = 4). Spur formula 2:4:4. Head, thorax, legs, and palps yellowish, setae of head and thorax golden (yellowish orange), postparietal sclerite and mesal suture of head slightly infuscated; basal antennal segments and basal half of subsequent segments brownish, apices yellowish; abdomen grayish brown; setae of wings, tibial spurs (and scant setae of legs) light to medium brown. Maxillary palps relatively short, segment I very short, globular, segments II and IV relatively short, subequal, segment II with apicomesal bristles, segments III and V subequal, moderate in length. Head very elongate (as in C. galeata Blahnik & Holzenthal, 1992, fig 1A), distinctly flattened, posparietal sclerite elongate (ca. as long as diameter of eye). Wings held flattened over dorsum of body, nearly horizontal. Wing venation typical for genus, forewing fork IV absent; hind wing 2A reduced to short stub ( Blahnik and Holzenthal 1992).

Male. Abdominal segments through VII with relatively sparse, fine setae on sterna and terga, denser posteriorly. Segment VIII relatively short, ca. ½ length of preceding segments, sternum with granulate surface sculpture (posterior margin with fringe of setae, plus premarginal setae mesally); setation of tergum like preceding segments. Segment IX relatively simple in structure, longer than segment VIII, anterior margin nearly linear (slightly concave), ventral margin weakly produced; posterior margin sinuously invaginated at level of inferior appendages, dorsal part setose, broadly rounded and somewhat produced; as viewed dorsally, with dorsal margin narrow, concavely narrowed from both anterior and posterior margins. Tergum X relatively short, bilobed, separated by short, narrow, submembranous mesal lobe; apices of lobes capitate, each with short, acute lateral projection; base of each lobe with prominent lateral conical sensillum; apices of lobes with numerous small sensilla. Preanal appendages short, rounded, fused with posterodorsal margin of tergum IX. Inferior appendages moderately elongate, more or less linear, but distinctly curved dorsad, tapering from base to apex, apex with short, acute projection, lateral margins densely setose, mesal margin with linear row of short, stiff setae, extending nearly length of appendage. Phallobase relatively short, with basodorsal expansion, ventral apex projecting, weakly sclerotized, broadly rounded as viewed dorsally or ventrally, internally with 2 short conical sclerotized spines, bases often slightly enlarged; endotheca emerging from tubular structure, distinctly sclerotized basally, membranous and down-curved apically, with short, tubular, weakly sclerotized phallotremal sclerite apically; dorsally with additional hood-like membranous lobe, simple in structure and not at all pleated.

Female. Segment VIII relatively short, with short, but distinct apodemes on anterolateral margin, posterior margin with 3 pairs of setal warts, posteroventral margin with mesal, setose, strap-like projection, fused basally to sternum IX. Tergum IX relatively short, with pair of elongate, narrow apodemes from anterior margin (shorter than length of segment VIII), posterior margin with ca. 3 elongate setae, clustered laterally on either side of segment IX, apically with pair of bulbous, setose projections (tergum X), each with short apical cercus and short setose projection from basoventral margin. Sternum IX short, rounded, lightly sclerotized, not extending beyond ventral strap of segment VIII. Vaginal apparatus membranous, indistinct, apically with small cup-like sclerite.

Holotype.

Male. ECUADOR: Imbabura: Reserva Los Cedros, tributary to Rio Los Cedros, 00.30374°N, 78.78229°W, 1312 m, 18-19.x.2011, Holzenthal, Ríos, Encalada, Acosta [UMSP000098416] (UMSP). Paratypes: ECUADOR: Imbabura: Reserva Los Cedros, small stream near station, 00.31127°N, 78.78150°W, 1460 m, 17.x.2011, Holzenthal, Ríos, Encalada, Acosta, 5 males (UMSP, MECN); Reserva Los Cedros; Rio de la Plata, 00.32495°N, 78.78084°W, 1587 m, 15.iii.2012, Ríos-Touma, Bragado, Policha, 1 male (UMSP); Reserva Los Cedros, Rio Los Cedros, 00.30359°N, 78.78233°W, 1312 m, 18-19.x.2011, Holzenthal, Ríos, Encalada, Acosta, 1 female (UMSP); Pichincha: Amagusa Reserve (private), Río Mashpi Chico “alto”, 00.15487°N, 78.85316°W, 1180 m, 17.i.2015, Holzenthal, Huisman, Ríos-Touma, 2 males, 2 females (NMNH, MECN); Río Malimpia in Mashpi Lodge, 00.17063°N, 78.88804°W, 700 m, 18.i.2015, Holzenthal, Huisman, Ríos-Touma, 1 female (UMSP).

Etymology.

Named for the Choco-Darién ecoregion, which occurs along the Pacific slope of the Andes from Panama to northwestern Ecuador and is known for its high level endemic biodiversity.