The first Cordyla Meigen species (Diptera, Mycetophilidae) from continental Australia and Tasmania

Abstract A new species of Mycetophilidae, Cordyla australica sp. n., is described from continental Australia and Tasmania, representing the first Cordyla record in the region. A detailed description of its morphology with illustrations of male and female terminalia and a map of the collecting localities are provided. According to the structure of male terminalia, Cordyla australica sp. n. belongs to the Cordyla murina species-group that has 13 species worldwide. Within the group Cordyla australica sp. n. resembles Cordyla murina but has a unique outline of the hypoproct and medial branch of the gonostylus. The observed distributional pattern is restricted to the rainforest of eastern Australia and Tasmania.


Introduction
The genus Cordyla Meigen, 1803, a member of the tribe Exechiini of Mycetophilidae, is a well delimited monophyletic clade of fungus gnats (Diptera: Sciaroidea). Having been treated earlier also in Mycetophilini (since Edwards 1925), the genus was transferred to Exechiini by Tuomikoski (1966). Within the tribe, Cordyla has a rather isolated position forming by Rindal et al. (2009) a common clade with Brachypeza Tuomikoski. However, the recently described genus Brachyradia Ševčík & Kjaerandsen including two species from the Oriental and Australasian (Papua New Guinea) regions shares several synapomorphies with Cordyla, and thus may be the closest relative instead of Brachypeza (cf. Ševčík and Kjaerandsen 2012). The Cordyla species are characterized mainly by short antennae with reduced number of flagellomeres and swollen antepenultimate palpal segment (Tuomikoski 1966) while by characters in male terminalia, the species are divided into three subgeneric groups (Kurina 2001). Cordyla specimens are easily recognisable by small size, humpbacked habitus in combination with mainly dark coloration and, especially, by swollen antepenultimate segments of palpi.
Thirty-eight described Cordyla species are known worldwide at present, viz. twentyfour from the Palaearctic region (Kurina 2005 and references therein, Sasakawa 2008), ten from the Nearctic region (Bechev 2000), three from the Oriental region (Ševčík 2001(Ševčík , Kurina 2005 and one from the Autralasian region: Northeastern Papua New Guinea (Kurina 2005). The genus is also known from undescribed species from the Neotropical region (Colombia (Oliveira et al. 2007) and Central America (Vockeroth 2009, OK and SSO pers. obs.)). There are no published records of Cordyla species from Afrotropical region.
The aim of this paper is to describe and illustrate the first Cordyla species from continental Australia and Tasmania and discuss its systematics.

Material and methods
The material was collected from seven localities in Tasmania using mostly Malaise traps, in few cases also pitfall traps or sweeping. A good amount of material comes from the Warra Long-Term Ecological Research Site (for details see Brown et al. 2001). In the Australian continent, the material was collected: 1) from Carrai and Werrikimbe Plateaus (both in NSW) during the tree trunk invertebrate survey by sticky traps (for details see Bickel and Tasker 2004); 2) from Brisbane Forest Park by Malaise traps and 3) from Victoria, Coopracambra National Park by Malaise traps. For collecting localities see Fig. 15. All specimens were stored initially in ethyl alcohol within which most of them -after studying under a stereomicroscope Leica S8APO or Leica MZ16 -are still preserved. In case of several specimens, for more detailed study of male terminalia, they were detached and macerated in a solution of KOH, followed by neutralization in acetic acid and washing in distilled water. The remaining chitinous parts were thereafter inserted into glycerine for study including illustrations and preserved as glycerine preparations in polyethylene microvials (cf. Kurina 2003). A few specimens including their terminalia were slide mounted in Euparal following the method described by Kurina (2008). The holotype was mounted from alcohol, using a chemical method described by Vockeroth (1966), and double-pinned. The preservation method of each specimen is indicated in the material section. The measurements are given as the range of measured specimens followed by the mean value. While not otherwise stated, five specimens were measured, while the measurements and setosity information from the holotype are given in square brackets. The ratios of the three apical palpal segments are given as 3 rd :4 th :5 th . All measurements are taken from specimens in alcohol. Morphological terminology follows generally that of Søli et al. (2000) while the interpretation by Kjaerandsen (2006) and Oliveira and Amorim (2012) are used for terminalia and thorax, respectively.
Female. Total length 2.2-3.4, 3.0 mm. Wing length 1.6-2.8, 2.2 mm. Ratio of length to width 2.5-2.9, 2.7. Antennae 2+9 segments. By setosity and coloration similar to male, except for entirely light brown abdomen in some specimen. Terminalia (Figs 12-14) light brown. Cercus two-segmented: apical segment small, apically tapering and bent laterad in ventral and dorsal views, with 2-3 long setae deviating from other setosity; basal segment long ovate, slightly sinusoidal and wider than apical segment. Gonapophysis VIII membranous, visible in ventral view, apically somewhat pointed. Tergite VIII rectangular, subequal to length of basal segment of cercus, api- cally angular, basally emarginated in dorsal view. Sternite VIII lateroapically conical, with deep ventral cleft. Tergite VII about twice as long as tergite VIII, with basal and apical broad incision dorsally and with a few apical stronger setae deviating from other setosity. Sternite VII apically conical, subequal to length of tergite VII. Tergite VI with conical and sclerotized apical edge laterally and with broad incision apicodorsally.

Biology. Unknown.
Etymology. The species is named to indicate its discovery in Australia. Comments. The species shows high variation (up to 35%) in body size that is, however, continuous and observed also in other Cordyla species (e.g. in European C. crassicornis Meigen, 1818: OK pers. obs.) and colour variation including some specimens darker than others. Despite of that, we have not found any species level morphological differences within the studied material.

Discussion
According to structure of male terminalia, Cordyla australica sp. n. belongs to the C. murina species-group as outlined by Kurina (2001). The species of this group have gonostylus with medial branch divided into two lobes of which outline and setosity are species-specific. Thirteen species belong to the group as follows: seven and five in the Palaearctic and Nearctic region, respectively and one from the Australasian region. Within the group, in respect to the number of flagellomeres -an important character for species grouping since Landrock (1926) -males of C. australica sp. n. shares 12 flagellomeres with 4 species, viz. C. murina Winnertz, 1863 (widely in Palaearctic), C. styliforceps (Bukowski, 1934) (southern Europe), C. bidenticulata Sasakawa, 2003 (Japan) and C. toraia Kurina, 2005 (South Sulawesi and Papua New Guinea). Having antepenultimate palpal segment dark brown to blackish, ventral branch of gonostylus with one serrated margin and notched dorsal part of hypoproct C. australica sp. n. is most similar to C. murina. However, the dorsal part of hypoproct is deeply notched and without lateral shoulders in C. murina, while the notch is shallow and lateral shoulders are well developed in C. australica. In the ventral part of the hypoproct, C. murina has lateral shoulders protruding over the slightly convex medial area, while the latter is well convex with subequal lateral shoulders in C. australica sp. n. Cordyla murina has the lobes of medial branch of gonostylus apically slightly swollen and billed, while they have a different outline in C. australica (cf. Fig 11). According to the key of Oriental and Australasian species (Kurina 2005), C. australica runs to the couplet 2 (C. toraia) but differing by the dark brown antepenultimate palpal segment (yellow in C. toraia), outline of hypoproct (cf. Fig. 7 and Kurina 2005: fig. 11) and other details in male terminalia.
In spite of wide range of the studied Australian samples (SSO pers. obs.), Cordyla australica sp. n. is apparently found only in wet forest of eastern Australia and Tasmania (Fig. 15).