The genus Keilbachia Mohrig from Mainland China, with descriptions of two new species (Diptera, Sciaridae)

Abstract Seven species of Keilbachia Mohrig are recognized, and among them, two new species, Keilbachia subacumina Wu & Zhang, sp. n. and Keilbachia fengyangensis Wu & Zhang, sp. n. are described and illustrated. Five species, Keilbachia orthonema, Keilbachia flagrispina, Keilbachia demssia, Keilbachia oligonema and Keilbachia acumina are reported for the first time from China. A key to the 15 Chinese species of this genus is also provided.


Introduction
Th e genus Keilbachia was fi rstly proposed for K. nepalensis Mohrig from Nepal (Mohrig and Martens 1987: 483). Subsequently, additional species are described from the Oriental, Palaearctic, Neotropical, and Australian Regions. Menzel and Martens (1995) described two species from Nepal-Himalaya. Mohrig et al. (1999) described four species from Nepal. Menzel and Mohrig (2000) transferred two Palaearctic species to Keilbachia. Mohrig (2004) described one new species from Papua New Guinea. Mohrig et al. (2004) described one new species from Dominica. Vilkamaa et al. (2006) described eight new species from Myanmar. Hippa and Vilkamaa (2007a, b) described 15 species from Oriental regions and reassigned one Nearctic species to the genus. Rudzinski (2008) described fi ve new species from Taiwan. Vilkamaa et al. (2009) reviewed the genus, adding 11 new species from Oriental Region and one more species by combination. Th erefore, 52 species of the genus have been recorded until now, mostly from the Oriental Region, including eight species that occur in Taiwan.

Materials and methods
All specimens were collected by sweeping in the fi eld and preserved in 75% ethanol. Th ey were mounted on glass slides in xylol-based Canada balsam after clearing in creosote. Th e heads of specimens from Yunnan province were bleached in 10% NaOH for about 24 hours at room temperature. Th e specimens were observed and measured under a Nikon SMZ1500 stereoscopic microscope. Th e illustrations were prepared under a Nikon Eclipse 50i optical microscope, with an attached drawing tube. Th e terminology follows Hippa and Vilkamaa (2007b). Th e length of 4th fl agellomere is taken from the apex of the neck to the base of the body. Th e wing length is the straight distance from the humeral angle to the apical angle. Th e body length is the straight distance between apex of head and apex of hypopygium. Th e type specimens designated in the present study are deposited in the collection of the Laboratory of Forest Protection, Zhejiang A & F University, Hangzhou, Zhejiang province, China [ZAFU].

Results and discussion
Key to Chinese Species of Keilbachia (Based on Males) Mesial megaseta of gonostylus long and strongly curved (Fig. 10)  Remarks . Th is species is new to China, which was fi rstly described from Nepal, based on two males. It is similar to K. ferrata (Hippa & Vilkamaa, 1994) in having two subapical megaseta and a long mesial megaseta, but K. fl agrispina can be separated by the mesial megaseta very long and strongly curved, and two subapical megaseta subequal in length on gonostylus. Th e materials examined from China do not show distinct variation, but we found the Chinese specimens are much smaller in body length, which is 1.64-1.71 mm, while 2.5 mm in Nepal materials.

Remarks .
Th is species is new to China, which was fi rstly described from Burma based on seven males. It is similar to K. scutica Vilkamaa, Komarova & Hippa, 2006 and K. fl agrispina by the tegmen broadest subbasally (Mohrig et al. 1999;Vilkamaa, Komarova and Hippa 2006). But it diff ers in having the mesial megaseta of the gonostylus much shorter and less strongly curved. Th e materials examined in China do not show distinct intraspecies variation, but the apical of gonostylus in the specimens SM00881 and SM00856 is more attenuated and curved than the other specimens.

Biology . Unknown.
Remarks . Th is species is new to China, which was fi rstly described from Sabah, Malaysia, based on two male specimens. It is similar to K. apprima Vilkamaa, Komarova & Hippa, 2006 from Vietnam by sharing a short mesial megaseta (Hippa & Vilkamaa 2007b), but K. orthonema can be distinguished by mesial megaseta longer and much less curved, and apical forth of gonostulus with two slender megasetae. Th e Chinese material examined does not show distinct intraspecies variation, but the two megasetae at the apical forth of the gonostylus are stronger than in Malaysia materials, judging from the fi gures prepared by Hippa and Vilkamaa (2007b). What's more, length/width of 4th fl agellomere is 2.47-2.53, smaller than in Malaysia materials, which is about 3 times as long as wide. Vilkamaa, Menzel & Hippa, 2009: 4. Diagnostic characters (Male). Body length 1.51-1.57 mm; wing length 1.25-1.28 mm.
Abdomen. Sternite 8 with 10-11 setae. Gonostylus and gonocoxa subequal in length. Gonostylus with two megasetae widely apart, one at apex and stout, the other at apical half of gonostylus and slender. Basal third of gonostylus excavated, with a long and strongly curved mesial megaseta on broad basal body. Tegmen simple, much broader subbasally than subapically, with sparsely placed teeth. (Figs 4, 5).
Specimens examined . Holotype, male. China, Zhejiang, Linan, Mt. Xijingshan, 30°23'N, 119°72'E, sweep-net, 21.VI.2008, Su- Biology . Unknown. Remarks . Th is species is very similar to K. acumina in the structure of the hypopygium (Fig. 5, 6), but K. subacumina can be distinguished by having the apex of gonostylus broader, and the stouter and shorter basalmost megaseta at the apical half of the gonostylus. What's more, the anterior pronotum bears 5-6 setae in K. subacumina while 3-4 setae in K. acumina, and the r-m nervation of the wing with 1-2 setae in K. subacumina while bare in K. acumina. Th e structure of the hypopygium in the new species does not show distinct intraspecies variation. Th e species is named after its similarity to K. acumina. Th is epithet is an adjective.  Distribution . China (Yunnan), Burma. Biology . Unknown. Remarks . Th e gonostylus of K. oligonema Hippa & Vilkamaa, 2007 with two long and curved mesial megaseta, and without apical and subapical megaseta. It is diff erent from all the other species in the group of fl agria, which has more than one mesial megaseta on the gonostylus. K. oligonema is unique in having diff erent characters in width of the eye bridge, setosity of sternite 8, and the ventral intercoxal area of the hypopygium between the holotype and two additional specimens, from which the authors suspected they may represent two diff erent species (Hippa & Vilkamaa 2007a). Th e same as the holotype of K. oligonema, the Chinese material has gonocoxa ventrally with a slight indication of an intercoxal lobe, but its four facets wide eye bridge, and six setose sternite 8 are similar to the additional materials.

Keilbachia fengyangensis
Figsures 7-11. Keilbachia fengyangensis, male. 7 4th fl agellomere, lateral view 8 palpus, lateral view 9 apex of protibia, prolateral view 10 gonostylus, ventral view 11 part of hypopygium, ventral view. Scale bar = 0.1 mm. and generous help. Special thanks are given to Dr. Hippa for his advice to improve the text. We also thank the collectors of the materials examined, Manman Wang from Zhejiang University and Shenglong Liu from Fengyangshan National Nature Reserve. Th is study was supported by NSFC grant 30870334.