© Hans Malicky/Austria; download unter www.biologiezentrum.at 37 BRAUERIA (Lunz am See, Austria) 33:37-38 (2006) Sexual diporphism helps deep diving in Potamyia johansoni n.sp. (Trichoptera: Hy dropsy chidae) Jânos OLÀH We had just published our revision of the Potamyia genus with 42 species (OLÂH, BARNARD and MALICKY, 2006) when I found an unusual species of Potamyia in freshly collected material from Laos. While sorting light trap material collected by N. Jönsson, T. Malm and P. Viklund during an expedition organised by Kjell Arne Johanson at the Entomology Department of the Swedish Museum of Natural History, I found seven females of an unusual and unknown Potamyia species. Its most striking feature was easily Potamyia johansoni <? recognised even at low magnification: Two thirds of the costal vein on the forewing were fringed with long, strong and forwardly directed modified black setae. It was surprising to recognise for the first time these uniquely equipped creatures with plenty of mini lancets. When examined under higher magnification, the distal end of the setae was observed as slightly tapering and moderately sinuous laterad in flying and posteriad in resting position. Finally near the end of sorting the rich light trap material, a single male was found in the same habitat without any modified setae on the costal vein of the forewing. Potamyia johansoni Searching for such a modified setae on the costal margin of female forewing the forewing in other caddisflies resulted in the discovery of the same type of erect and black hairs in Potamyia light brown; anteromesal setal wart accompanied with a pair czekanowskii (MARTYNOV, 1910), a widely distributed of small warts; behind the pair of the elongated anterior setal species and with huge biomass in the large Siberian rivers. warts, there are a pair of setal groups composed of 4-5 MARTYNOV (1910) has described these hairs as species smaller warts of different size; the pair of posterior setal character, not limited to the female only. In his later warts large. Swollen setal wart absent on proepisternum. description (MARTYNOV, 1934), this character was mentioned Protarsal claw asymmetrical with laterally flanked setal again as a special feature of the species. Thanks to Kjell Arne bundle. No spurs present on the first tibia, spur formula 044. Johanson, I was able to examine a large amount of light trap Forewing length 6,5 mm, hindwing length 4,8 mm. In the material of this species collected at thevAmur River (Russia, forewing, the crossvein cu is apicad of crossvein m-cu about Khabarovsk Ter. Slavyanka at Amur, light trap, 17.vi. 1994, the length of the crossvein; Cu2 and A joining before C; leg. P. Kindskog et B. Viklund). I have found that all the crossveins sc-rl and rl-r2+3 absent; pale pterostigmal area females, but not the males of P. czekanovskii have the enlarged. The erect black modified setae on the costal margin modified setae on the costal margin of the forewing. of forewing present on the middle two thirds of the female However the modified setae at P. czekanovskii are shorter wing (Fig. 1). In the hindwing, stem of M plus proximal part and distributed at about one third length of the costal margin. of M3+4 almost touching and running parallel with Cui; fork It seems that these enforced modified setae indicate a sexual 1 present; Sc and Rl joining around crossvein r. dimorphism in these species. The modified setae may have a Male genitalia (Fig.2). Ninth abdominal segment swimming function during the deep (up to 7-8 m, OLÂH et al. short and almost evenly annular, anteriorly only slightly 2006) diving action of the ovipositing female. rounded, dorsal corner truncate, dorsum not narrowing more than ventrum, apical lobe on posterolateral margin forms a Potamyia johansoni new species flat plate from the tenth segment to the base of the inferior appendages. Spine row on the posterior margin of the 9th The new species belongs to the Potamyia flava species group segment intermittent, the area at the 10th segment without (OLÂH, BARNARD and MALICKY, 2006). It is closely related spines, the spines on the flat apical lobe strong, submarginal to P. straminea (MCLACHLAN, 1875), but the new species has and arranged in a vertical line. Dorsocaudal spiny lobe a clasper which does not taper, 10th segment extremely stocked with a group of long spines slightly separated tapering as visible in dorsal view and its apex not bifid, just medially. Intersegmental depression between the ninth and excised at the very tip. Moreover the phallotheca differ, being tenth segments forming a right angle. Tenth segment flatter, its basal half not developed, endothecal process elongated and broad basally; subtriangular both in lateral and regularly rounded and not elongated at all. The female has the dorsal views, however in dorsal view very sharply triangular, characteristic modified strong setae along the costa of the unusually almost tapering; its apex formed by the forewing. However the presence of this modified setae was ventroapical setose lobe with very small excision into a pair not examined systematically in the females of the Potamyia of upturned small spiny projections; its sclerotised genus. continuation along the ventral margin of the tenth segment Male (in alcohol). Body and wing membrane light reaching the posterior margin of the ninth segment; dorsal brown with light pubescence. Wing membrane homogenous interlobular gap of the small excision small and shallow; without any pattern. Antennae broken. Dorsum of the head dorsoapical setose lobe moved backward, forming a setose © Hans Malicky/Austria; download unter www.biologiezentrum.at 38 hump in lateral view; lateral setose area (preanal appendages) flat, shifted ventrad and elongated; transverse suture not discernible; longitudinal suture running along the ventral margin of the 10th segment as the continuation of ventroapical lobes. The basal segment of inferior appendages almost as long as the apex of tenth segment, straight and only slightly dilating distally; the second segment broad digitiform in lateral and broad falciform in ventral views. Phallotheca flat, with slightly wavy dorsum, but almost straight; ventral subapical keel well developed; chitinesed endothecal process regularly rounded, phallotremal sclerites small, narrowly horizontal in lateral aspect; endophallus long with a very visible sclerous band, membranous endothecal lobes not visible on the less sclerotized ventroapical corner. Holotype male: Laos PDR, Luang Namtha Prov., Tong Om Village, 552mao, 47Q 0750111, UTM 2321825, 1 May 2005, light trap, loc 30; N. Jönssson, T. Malm and B. Viklund leg., in the collection of Entomology Department of the Swedish Museum of Natural History, Stockholm. Paratypes: 6$: same as holotype. 1$: Laos PDR, Vientiane Prov., Vang Vieng, Nam Xong River, upstream bamboo footbridge, 363mao, 48Q 0223506, UTM 2115465, 26 April 2005, Light trap, loc 10; N. Jönssson, T. Malm and B. Viklund leg. - Allotype: 1$: same data as holotype. - Distribution: Laos. Etymology: Named in honor of Kjell Arne Johanson. References MARTYNOV A. 1910. Les Trichoptères de la Sibérie et des régions adjacentes. Il-e partie. La sousf. Brachycentrinae. Les fam. des Molannidae, Leptoceridae, Hydropsychidae, Philopotamidae, Polycentropidae, Psychomyidae, Rhyacophilidae et des Hydroptilidae. Ann. Mus. Zool. Acad. Imp. Sci. Petersbourg 15(4):351-429. MARTYNOV A. 1934. Trichoptera. Annulipalpia. Tableaux analytiques de la Faune de l'URSS, Publiés par l'Institut Zoologique de l'Académie des Sciences, Leningrad. OLÀH, J., BARNARD, P., MALICKY, H., 2006, A revision of the lotie genus Potamyia BANKS 1900 (Trichoptera: Hydropsychidae) with the description of eight new species. - Linzer biol. Beitr. 38:739-777. Dr. Jânos Olâh, Department of Environmental Management, Tessedik College, I. kk. 10, H-5540 Szarvas, Hungary saker(alszarvasn et. hu