Chimarra (Chimarra) onchyrhina Blahnik & Holzenthal

Blahnik, Roger J. & Holzenthal, Ralph W., 2012, New Neotropical species of Chimarra (Trichoptera, Philopotamidae), ZooKeys 184, pp. 1-33 : 6-7

Chimarra (Chimarra) onchyrhina Blahnik & Holzenthal sp. n. Figs 2 A–F 9

Description.

This species is very similar to Chimarra platyrhina Flint, 1981, especially in the general shape of the lateral lobes of tergum X, as viewed dorsally. In both species, the lateral lobes of tergum X each have a broadly rounded apicolateral projection. The difference in shape of this projection, however, is distinctive and diagnostic, that of Chimarra platyrhina being broad and uniformly rounded, and that of Chimarra onchyrhina being somewhat angular laterally. Both species also have a linear cluster of small spines located near the ventral apex of the endotheca, also present in some other species of the Chimarra ortiziana group. The latter character is, however, absent in Chimarra ortiziana , which otherwise resembles Chimarra onchyrhina in the general shape of the apex of the lateral lobes of tergum X. An additional difference separating them is that Chimarra ortiziana has the lateral sensilla of tergum X placed on a concavely developed lateral projection. The lateral projections of Chimarra onchyrhina and Chimarra platyrhina are simple in structure. The female genitalia of Chimarra onchyrhina also generally resemble Chimarra platyrhina , especially in the shape of apical sclerites of the vaginal apparatus. However the vaginal apparatus has distinctive lateral projections, not present in Chimarra platyrhina . The overall similarities of these species, both in male and female genitalia, are indicative of their sister relationship.

Adult. Forewing length (male) 3.9-5.0 mm, (female) 4.8-5.5 mm. Cuticle of head and thorax dark brown, setae of anteromesal and frontal setal warts whitish, setae of other setal warts dark brown, grizzled (grayish in part or intermixed), femora brown, otherwise color nearly uniformly brownish-black (fuscous), including appendages and antennae. Postocular parietal sclerite very short (not extended behind eye). Second segment of maxillary palp much shorter than segment 3 (about 2/3 length). Male protarsal claws enlarged, asymmetrical in size and shape, outer claw much larger, twisted, nearly linear apically.

Male genitalia. Abdominal segment IX, in lateral view, with pronounced sinuous extension of anteroventral margin and with distinct apodemes from anterodorsal margin; posteroventral process moderately elongate, subtriangular, relatively broad basally, subacute apically. Tergum X membranous mesally, with 2 sclerotized lateral lobes, each bearing short rounded projection laterally in basal portion, with 2 sensilla on tiny projections; terminus of lateral lobe inflated, broadly rounded, but with distinct, obtuse angle on lateral margin. Preanal appendage short, knob-like. Inferior appendage, in lateral view, with rounded to subquadrate base, subacute apically; dorsally with flattened, thumb-like extension, flexed caudally as viewed laterally, and mesally as viewed caudally; apex of thumb-like projection rounded. Phallotheca with apicoventral margin projecting; endotheca forming collar of minute spines in apical 1/2, slightly ballooned laterally, apicoventrally with sclerotized region possessing array of short spines, endothecal spines 2, very short, subequal in length. Phallotremal sclerite complex composed of elongate rod and ring structure with associated pair of wishbone-like sclerites from anteroventral margin.

Female genitalia. Sternum IX with ventral lobes broadly truncate apically. Vaginal apparatus, as viewed ventrally, with paired, subtruncate, lightly sclerotized apicoventral sclerites; laterally with short projecting sclerotized lobes on either side, each with short, digitate apical projection; vaginal apparatus anteriorly with deflexed, cup-like sclerite and elongate, paired, dorsolateral and ventrolateral sclerites, these extending more than ½ length of vaginal apparatus.

Holotype

, male (pinned) (UMSP000026958):VENEZUELA:Sucre: Península de Paria, Puerto Viejo, “Río el Pozo", 10°43.073'N, 62°28.569'W, 20 m, 3.iv.1995, Holzenthal, Flint, Cressa (UMSP).

Paratypes.

VENEZUELA: Falcón: Quebrada El Charo at cataratas, 10°46.771'N, 69°12.174'W, 425 m, Holzenthal, Blahnik, Paprocki, Cressa, 3 males (alcohol) (UMSP); Monagas: Guachero Cave N.P., 10°10.322'N, 63°33.315'W, 1110 m, 20-21.vii.2010, Holzenthal, Thomson, Cressa, 4 males, 6 females (pinned) (UMSP); Sucre: same data as holotype, 12 males (pinned), 33 males, 20 females (alcohol) (UMSP); Península de Paria, Santa Isabel, Río Santa Isabel, 10°44.294'N, 62°38.954'W, 20 m, 4.iv.1995, Holzenthal, Flint, Cressa, 9 males, 1 female (pinned), 28 males, 45 females (alcohol) (UMSP); Península de Paria, Puerto Viejo, Río Puerto Viejo, 10°43.137'N, 62°28.743'W, 15 m, 2.iv.1995, Holzenthal, Flint, Cressa, 3 males (pinned), 20 males, 60 females (alcohol) (UMSP); Parque Nacional Península de Paria, Río San Francisco, 10°42.713'N, 62°00.066'W, 10 m, 1.iv.1995, Holzenthal, Flint, Cressa, 2 males (pinned) (UMSP); Parque Nacional Península de Paria, Uquire, Río La Viuda, 10°42.830'N, 61°57.661'W, 15 m, 30. iii– 1.iv.1995, Holzenthal, Flint, Cressa, 15 males (pinned), 18 males, 43 females (alcohol) (UMSP) (NMNH) (MIZA); Quebrada Zapateral, 1.5 km SE Las Piedras de Cocollar, 10°09.753'N, 63°47.587'W, 810 m, 9.iv.1995, Holzenthal & Flint, 2 males, 1 female (alcohol) (NMNH); Río Cocollar, 1.5 km SE Las Piedras de Cocollar, 10°09.617'N, 63°47.605'W, 810 m, 7-8.iv.1995, Holzenthal & Flint, 12 males, 10 females (alcohol) (MIZA).

Etymology.

This species is named Chimarra onchyrhina from the Greek words onkos, meaning a hook or angle, and rhinos, a nose, and referring to the slightly angled lateral process on tergum X of this species, which distinguishes it from the more uniformly rounded process in Chimarra platyrhina .