Three new species of Helicopsyche ( Trichoptera , Helicopsychidae ) from northern Vietnam , with a key to Helicopsyche species of Vietnam

Three new species of Helicopsyche Siebold, 1856 are described from Vietnam: Helicopsyche melina sp. nov., Helicopsyche meander sp. nov., and Helicopsyche lamnata sp. nov. All species were described from melinh Station for Biodiversity in the me Linh District of Vinh Phuc Province. The species were collected mainly in malaise traps situated across a small stream surrounded by lowland forest. Some individuals were also collected on light in traps situated at the stream bank.


Introduction
With 270 described species the snail-case caddisfly genus Helicopsyche Siebold, 1856, ranks as the tenth largest genus in the order Trichoptera.The genus has been recorded from all major faunal regions, except Antarctica (Johanson 1998) and has the highest species diversity southern latitude interval 5-30° and southern latitude interval 15-45° (Johanson 1997).With 30 described Helicopsyche species (Johanson 1999), the 17,000 km 2 large New Caledonian Grande Terre has the highest density of species in the world.The larva of all species are reported to build dextrally coiled larval cases made from sand grains and glued together by silk.They live in permanent and preferably running water bodies, often in well-shaded forest streams and rivers.The 71 previously described Helicopsyche species of the oriental Region (morse 2011) are classified in two subgenera, Galeopsyche Johanson, 1998and Helicopsyche Siebold, 1856(Johanson 1998).The first record of Helicopsyche from Vietnam was that of Helicopsyche azwudschgal malicky, 1995, described from Tam Dao National Park at 800-1,100 m altitude.Schefter & Johanson (2001) described three more species from the country: Helicopsyche khemoiensis Schefter & Johanson, 2001 (from Nghe An District), Helicopsyche azunensis Schefter & Johanson, 2001, and Helicopsyche dacklestensis Schefter & Johanson, 2001 (the two latter from Gia Lai District).malicky (2010) listed the following two additional species from Vietnam: Helicopsyche boniata malicky & Chantaramongkol, 1992, Helicopsyche admata malicky & Chantaramongkol, 1992, both originally described from Thailand.With the addition of the three new species recorded and described below, the known diversity of Helicopsyche in Vietnam is nine species, only slightly lower than found in Thailand (fourteen spp.).This research was executed to increase our knowledge about the taxonomic species diversity and morphological variation in the family Helicopsychidae, as well as to increase our understanding of the biogeography of individual species in the group.

Material and methods
The material was collected in light traps between 4-5 th April and malaise traps between 4-12 th April 2011 in the Vinh Phuc Province, me Linh District, at a stream near Ngoc Thanh Village, melinh Station for Biodiversity.It comprises 357 male and 81 female Helicopsyche; the males divided into three species while the females are not associated or determined.
The specimens were identified to morphospecies without initial treatment of the genitalia.Before illustrated the abdomen of the species were macerated in ProteinaseK for extraction of DNA, and for a short period in hot 8% KoH to remove remaining tissue.Each abdomen was temporarily mounted in Euparal on a microscope slide and illustrated using a drawing tube mounted on a Leitz ortholux II light microscope.The individual illustrations were scanned in 600 dpi gray scale and used as a digital background layer in Adobe ® Photoshop ® CS v.8.0.The final illustration was drawn using a Wacom ® sketchpad and digital pen.After illustration, upper layer was saved into final illustrations.The abdomen with genitalia was thereafter transferred into 80% ethanol in a micro-vial, together with the rest of the specimen.Terminology for morphological characters mainly follows that of Johanson (1998)  ) particularly due to the presence of four-segmented maxillary palps in combination with the nearly similar shape of the gonopods and tergum X in lateral view.The new species is easily distinguished from these by the presence of a well-developed transverse plate of segment IX located at mid-height of posterior part of the segment; the primary branch of each gonopod is produced anterad; and the secondary branch of each gonopod is long, straight, and oriented in right angle to the primary branch of the gonopods.

Etymology
Melina, named after the melinh Station for Biodiversity, near the type locality.

Description
Maxillary palps.Four-segmented, each segment gradually shorter distally.Pair of interantennal setal warts bean shaped, each about as long as width of individual scapus.Each scapus about as long as each basal segment of maxillary palps.Spur formula 1,2,4; each foreleg spur slightly shorter than each first tarsomere.
Male abdoMen and genitalia.(Fig. 1) Sternal process VI about one-fifth as long as sternum VI, straight, oriented posteroventrad; slightly tapering in lateral view (Fig. 1A); with slightly club-shaped apex in ventral view (Fig. 1B).Segment IX about as long as high in lateral view (Fig. 1C); each anterior lobe of segment IX (Fig. 1C) narrowly and symmetrically ellipsoid in lateral view, oriented anterad; anterodorsal and anteroventral margins almost straight (Fig. 1C); in dorsal view, inner margin forming narrowly ellipsoid cavity (Fig. 1D); in ventral view, without central posterior process (Fig. 1E); inner margin forming nearly triangular cavity; lateral apodemes nearly horizontal (Fig. 1C), widening anteriorly, meeting anterior margin, sub-marginal line absent; tergal transverse apodemes well-developed; sternal transverse apodeme absent.Transverse plate of segment IX located at mid-height of posterior margin of segment IX; in lateral view almost club-shaped, curving ventrad (Fig. 1C); in ventral view forming broadly heart-shaped plate above basal part of gonopods (Fig. 1E).Tergum X, in lateral view, oriented posterad (Fig. 1C), almost straight, tapering along its length; apex strongly pointed (Fig. 1D); in dorsal view (Fig. 1D), deeply divided into pair of tapering, divergent branches, with about 3 pairs of equally long megasetae in apical group, starting opposite to apex of gonopods in lateral view (Fig. 1C).Superior appendages tubular (Fig. 1D), slightly curving dorsally.Primary branch of gonopods, in lateral view (Fig. 1C), oriented dorsally, broadened distad to mid-height; anterior margin smooth, strongly concave; dorsal and posterior margins edged, undulating, posteroventral margin almost straight (Fig. 1C); apices produced mesad into rounded lobes above basolateral part of tergum X. Secondary branch of gonopods nearly as long as secondary branch of gonopods; slender, almost straight in lateral view, except apex slightly curving dorsad; with few setae; curving mediad in ventral view (Fig. 1E).Basomesal lobes absent.Basal plate, in lateral view (Fig. 1C), nearly straight, narrowing along its length, slightly produced beyond anteroventral margin of segment IX in lateral view (Fig. 1C); narrow in ventral view (Fig. 1E).Phallic apparatus, lateral view, tube-shaped along its length (Fig. 1F), narrowest shortly after basis, apex about as broad as base; nearly straight after mid-length; in ventral view, with basis narrow (Fig. 1G); widest immediately after mid-length; endotheca weakly produced, posteroventral part not sclerotized, except pair of weakly sclerotized pair of triangular processes distally of phallic sclerite.

Description
Maxillary palps.Two-segmented, with distal segment slightly longer than basal segment.Pair of interantennal setal warts semi-spherical, elevated.Each scapus about as long as each basal segment of maxillary palps.Spur formula 1,2,4; each foreleg spur slightly shorter than each first tarsomere.

Description
Maxillary palps.Two-segmented, all segments sub-equal in length.Pair of interantennal setal warts very large, spherical, elevated, densely covered by long setae.Each scapus slightly longer than individual segments of maxillary palps.Spur formula 1,2,4; each foreleg spur nearly as long as each first tarsomere.
Johanson & malm, 2007 lamnata sp.nov. is most similar to H. vongsombathiJohanson & malm, 2007, from which it is easily distinguished by the presence of a central posterior process of segment IX and the distal part of the gonopods are more strongly produced posteriorly.The species also resembles H. meander sp.nov., particularly by the nearly club-shaped apex of tergum X in lateral view, but in H. lamnata sp.nov. the VI th sternal process is much longer and the gonopods are less sharply sigmoid.plate-like in Latin, refers to the process on the posterior margin of sternite IX.VIETNAm: Vinh Phuc Prov, me Linh District, stream near Ngoc Thanh Village, melinh Station for Biodiversity, 21°23'28.2"N,105°42'46.7"E,233 m, malaise trap 4-12 Apr.2011, loc#VN001, leg.K.A. Johanson, P.H. Thai & T.T.Du (NHRS, alcohol) [DNA voucher IP9].