Six new species of Dasyhelea (Insecta, Diptera, Ceratopogonidae) from Patagonia

Six new species of Dasyhelea Kieffer, 1911 from Argentinean and Chilean Patagonia are described and illustrated based on adults. Five of these species do not belong to any of the recognized groups found in the Americas. The remaining one, Dasyhelea pabloi sp. nov. is a typical member of the leptobranchia group and is the first record of a species from this group found in the Neotropical region.

is a large and complex genus of Ceratopogonidae with diverse morphology and biology, occurring worldwide in a variety of habitats (WAUGH & WIRTH, 1976).
Taxonomically, the recognition of subgenera and/ or species groups is still incipient and generally have been applied sporadically only to various regional fauna.With regard to the Nearctic region, WAUGH & WIRTH (1976) reviewed the cincta, grisea, leptobranchia and mutabilis groups, BORKENT & FORSTER (1986) the fasciigera group and GROGAN & WIENERS (2006) the brevicornis group.BORKENT (2009) mentioned 58 species for the Neotropics.Of these, 40 species belong to the groups recognized for the Nearctic region except the leptobranchia group, and the remaining 18 could not be grouped mainly due to their very incomplete original descriptions and, as it is the case of the species described by KIEFFER (1917), the inexistence of types.
During the past 20 years several collecting trips to many localities in Argentinean and Chilean Patagonia were undertaken, resulting in a large collection of adults of the genus Dasyhelea, deposited in the Museo de La Plata, Argentina.The taxonomic revison of this collection reveals the presence of 28 species, three of the cincta group (reviewed by DÍAZ et al., 2009), seven of the patagonica group, recognized during this study (DÍAZ et al., 2010), 12 of the mutabilis group (unpublished data), one of the leptobranchia group and five that do not fit in any of the already recognized groups for the Americas.The purpose of this paper is to describe and illustrate the lastly mentioned six species.

MATERIAL AND METHODS
All specimens were slide mounted in Canada balsam, examined, measured and drawn using a binocular compound microscope with attached camera lucida.Terms for structures of adults follow MCALPINE et al. (1981).Terms for wing veins follow the system of MCALPINE et al. (1981), with modifications proposed by SZADZIEWSKI (1996).
The holotypes of the new species are deposited in the collection of the División Entomología, Museo de La Plata, Argentina (MLP).When available, paratypes will be deposited, as noted, in the Natural History Museum, London (NHM).During this investigation we studied the specimens collected by Anthony J. Downes in southern Chile, which are housed in the Canadian National Collection of Insects (CNCI).When the specimens belong to the later collection, it is written the collector nomenclature after the locality (e.g., JAD 1702/1).Diagnosis.The only species of Dasyhelea from Patagonia distinguished by the following combination of characters: tip of posteromedian projection of male sternite 9 rounded, parameres symmetrical, its basal arms not fused to bristle-like posteromedian projection, aedeagus with forceps-like posterolateral projections.Female subgenital plate small and subtriangular, spermatheca rounded with long, oblique neck.
Distribution.Argentina (Salta, La Rioja, Córdoba and Río Negro provinces).Etymology.This species is named after Mr. Héctor "Machala" Ferreyra, technicien of the División Entomología of the Museo de La Plata, in recoginition of the valuable support given to entomologist during the past fifty years.
Discussion.This species inhabits the Patagonian steppe, and also extends its distributional range to arid zones of the northern provinces of Salta, La Rioja and Córdoba.
Dasyhelea ferreyrai is similar to the Etiopic species D. monostycta (Ingram & Macfie, 1923), especially by the parameres shape.However, D. monostycta has banded legs, the posteromedian projection of the male sternite 9 is convex, the gonostili are shorter and the adeagus is shield-shaped.The female subgenital plate is rectangular and the neck of the spermatheca is clearly shorter.Diagnosis.The only Neotropical Dasyhelea with male sternite 9 stout with H-shaped posteromedian projection and a calyx-shaped hyaline envelope, cubital fork at same level of first radial cell.Female with two ovoid spermathecae.
Distribution.Argentina (Tierra del Fuego province), Chile (Deceit island).Discussion.Dasyhelea grogani is similar to D. calvescens Macfie, 1938, a species inhabiting the Hawaiian and Wake islands, Mexico and Panama, especially by the posteromedian projection of sternite 9 and the symmetrical parameres.However, in D. calvescens the posteromedian projection of the male sternite 9 bears a distinct, slender, posteromedian process, the posterolateral arms of the aedeagus are nearly convergent and the posteromedian projection of the parameres is distinctly shorter; the female mainly differs by the divided subgenital plate and by the narrow and longer spermathecae necks.DÍAZ et al. (2010) proposed the Dasyhelea patagonica group and reviewed the seven included species, all from Argentinean and Chilean Patagonia.They also pointed out the similarities (presence of two well developed spermathecae and symmetrical parameres) and differences (ventral surface of the aedeagus covered by a hyaline envelope) with the subgenus Sebessia Remm, 1971.Although D. grogani has two well developed spermathecae and shares most of the characters with the D. patagonica group, it is a very hairy species and lacks the strong sclerotization around the gonopore.On the other hand, the male sternite 9 of this new species exhibits a calyx-shaped hyaline envelope, and could be assignated to the D. holosericea group whitin the subgenus Sebessia.Nevertheless, we prefer not to include it within Sebessia at this time, at least until specialists increase the knowledge on the immatures of the genus, which hopefully would provide new, valuable characters in order to properly propose a phylogenetic classification.Diagnosis.The only Neotropical Dasyhelea with male sternite 9 conspicuous, gonocoxite with short and double curved anteromedian process and symmetrical parameres fused to small posteromedian projection, cubital fork slightly distad to end of costa.Female unknown.
Distribution.Argentina (Río Negro and Chubut provinces).Etymology.This species is named after our friend and colleague Dra.Cecilia Melo, entomologist of the Instituto de Limnología "Dr.Raúl A. Ringuelet".
Discussion.Dasyhelea meloae, only known from steppe areas of Patagonia, is similar to D. pailemanensis sp.nov., sharing a very conspicuous male sternite 9, symmetrical parameres and the inner margin of the gonocoxites bearing a tuft of strong setae.However, the legs of D. pailemanensis exhibit subbasal pale rings on tibiae, the distal margin of the posteromedian projection of sternite 9 is convex, and the aedeagus is bilobed with its posterolateral arms internally serrate, among other differences.
Dasyhelea pabloi Díaz & Spinelli sp.nov.Diagnosis.Only species of the leptobranchia group with posteromedian projection of male sternite 9 U-shaped and posterolateral arms of aedeagus subparallel with recurved tip.Female subgenital plate divided, its anterior portion elongate and posterior one subquadrangular, spermatheca rounded with straight neck.
Thorax.Scutum dark brown; scutellum with 8-10 long setae, 4-6 shorter ones.Legs dark brown, tarsi slightly paler; hind tibial comb with 6 spines; prothoracic TR 2. 06 (1.88-2.22, n=6), mesothoracic TR 2.09 (2.00-2.27,n=7), metathoracic TR 2. 01 (1.84-2.36, n=7).Wing (Fig. Discussion.This species not only inhabits both main biomas in Patagonia, steppe and subantarctic Nothofagus forests, but also extends its distributional range to the northern provinces of Jujuy and Salta. Dasyhelea pabloi belongs to the leptobranchia group, as diagnosed by WAUGH & WIRTH (1976).It is very similar to the Nearctic species D. brevicosta Waugh & Wirth, 1976 especially by the short costa, and also by the gonostili and parameres shape.However, in D. brevicosta the posteromedian projection of the male sternite 9 is serrate, the anterior margin of the aedeagus is straight and the posteromedian projection of parameres is clearly stouter and its recurved tip shorter; the female maily differs by the anterior portion of the subgenital plate subtriangular and by the very narrow and longer spermatheca neck.This is the first record from the Neotropical region of a species belonging to the leptobranchia group.
Distribution.Known only from the type-locality.