Review of the Fannia postica-group Chillcott, 1961 of the genus Fannia Robineau-Desvoidy, 1830, with description of two new species from the Palearctic and Oriental regions (Diptera, Fanniidae)

Abstract A total of 17 species of the Fannia postica-group Chillcott, 1961 from the Palearctic and Oriental regions are reviewed herein, 2 of which are described from China as new: Fannia ningxiaensis Wang & Zhang, sp. n. and Fannia subaethiops Wang & Zhu, sp. n.. Fannia labidocerca Feng & Xue, 2006, originally placed in Fannia serena-group Chillcott, 1961, is moved to the postica-group and re-described. An identification key to the males of known species from these regions is provided.

At the end of the nineteenth century, Stein (1895) described the Palearctic and Oriental species, F. postica (Stein). Since the beginning of the twentieth century, a number of papers and monographs studying the European species of F. postica-group have been published (Ringdahl 1926, Collin 1939, Hennig 1955, D'Assis-Fonseca 1968, Rognes 1982, Gregor and Rozkošný 2005. Pont (1986) reviewed the Palearctic fanniids, including species of the F. postica-group. Rozkošný et al. (1997) treated species of the Family Fanniidae from Europe and added nine species to the F. postica-group.
Asian species of the F. postica-group were mainly reported on by Nishida (1975Nishida ( , 1976, Pont (1977), Fan (1992), Xue and Wang (1998), Xue et al. (2001), Wang and Xue (2002) and Wu and Wang (2002). Wang et al. (2011) listed 22 known species of this group worldwide, recorded nine species of the postica-group from China and, based on the definition of the group by Chillcott (1961), summarized features of the male habitus and terminalia that distinguish it from other Fanniidae.
The biological characteristics of these species have never been fully studied. The study of specimens in our entomological collections has revealed that the majority of species in the group occur in wooded or shrubby habitats. According to Rozkošný et al. (1997), the immature stages of some species, such as F. umbrosa (Stein), live in birds' nests or in sap flowing out of rotholes in trees. The larvae of F. postica (Stein) and F. umbrosa (Stein) feed on humic substances, whereas the larvae of F. postica (Stein) also develop in carrion (Rozkošný et al. 1997).
In this paper, we review 17 known Palearctic and Oriental species belonging to the F. postica-group. Based on an extensive literature search and study of dry specimens, a key to the identification of males of known species from these regions is given, and two new species from China are described. One species, F. labidocerca Feng & Xue, 2006, is transferred from the F. serena-group to the F. postica-group and re-described. Illustrations of the male terminalia are included.

Material and methods
The morphological terminology used in this paper follows McAlpine (1981), except for the term "postpedicel", which follows Stuckenberg (1999). Absolute measurements in millimeters (mm) are given for body length. The specimens studied for this paper are deposited in the Institute of Entomology, Shenyang Normal University, Shenyang, China (IESNU) and the Shanghai Entomological Museum, Chinese Academy of Science, Shanghai, China (SHEM). Figure of Fannia labidocerca Feng & Xue, 2006 is from Feng and Xue (2006). Methods for the preparation of terminalia and illustrations follow Zhang et al. (2013).

Fannia aethiops Malloch, 1913
Fannia aethiops Malloch, 1913 Redescription. MALE. Body length 4.8 mm. Eye with short and distant hairs or bare; postocular setae in 2 rows, those of the anterior row sparse and long, curved anteriorly, those of the posterior row short; fronto-orbital plate and parafacial with silvery-white pollinosity; frons at narrowest point slightly wider than the distance between outer margins of posterior ocelli; frontal vitta black, at narrowest point about as wide as fronto-orbital plate; frontal setae 12, stout, situated on the lower 4/5 of frons, orbital setae absent; parafacial bare, at middle about 1/3 as wide as the width of postpedicel; antenna black, postpedicel about 2.0 to 2.5x as long as wide, arista ciliated, the longest individual hairs shorter than aristal base; epistoma not projecting beyond vibrissal angle, vibrissal angle behind frontal angle in profile; genal height about 1/14 of eye height; prementum shining, about 3.0x as long as wide; palpus dark brown, claviform, slightly shorter than prementum. Thorax ground-color black, notum with dark brown pollinosity; presutural acr biserial, long, one pair of them slightly stout, only prescutellar pairs stout, dc 2+3, ia 0+2, pra 2, about 2/5 of length of posterior notopleural seta; notopleuron bare; basisternum, proepisternum, anepimeron, meron and katepimeron bare; katepisternal setae 1+1, katepisternum without a ventral spine; spiracles brown; calypters mostly brown or brownish, brownish on the outer margin, the lower one small and tongue-like, about 1/2 as long as the upper one. Wing brownish; veins and wing-base yellow; basicosta brownish-yellow; costal spine inconspicuous; node of Rs bare on ventral and dorsal surfaces; vein M 1+2 straight, parallel to vein R 4+5 distally; crossveins not clouded; haltere brown in basal part, yellowish at middle and dark brown in distal part. Legs entirely black, sometimes dark brown or brown; fore tibia without p; mid coxa without any hook-like spine or spine-like seta; mid femur concave on ventral surface in apical part, becoming swollen from distal 1/3 towards basal part, with a row of av, stout in basal part, becoming shorter and denser in distal 1/4, with a cluster of spine-like setae in distal 1/3, a complete row of ad, slightly short (Fig. 1A), with a complete row of slender p, slightly situated on the posteroventral surface, with a row of pv in basal 4/5, and with a row of setulae at middle towards distal 1/4; mid tibia slightly swollen towards apex, in distal half with one ad, one preapical d, one pd, and with numerous slender setulae on ventral surface, most of the setulae longer than mid tibial width in distal part (Fig.  1A); mid first tarsomere with a basal tooth-like spine on ventral surface; hind coxa bare on posterior surface; hind femur with 3 stout av in distal 1/3, without pv; hind tibia with one av, one ad and one median d. Abdomen long and flattened (Fig. 1D), groundcolor black, with thin gray pollinosity; syntergite 1+2 and tergites 3-5 each with one dark median triangular vitta (Fig. 1D); sternite 1 with 4 long lateral marginal setae; for morphology of sternites 5 and 9 and terminalia, see Fig. 1B, C, E, F. FEMALE. Unknown. Remarks. Feng and Xue (2006) placed F. labidocerca into the F. serena-subgroup of the F. serena-group while recording the species from the Mt. Emei Region, Sichuan, China. However, this species should be placed into the F. postica-subgroup by sharing the following morphological characters with all other species of the subgroup: mid first tarsomere with a distinct basal tooth-like spine on ventral surface; lower calypter short, tongue-like (Fig. 1E, F).
Type specimens examined. Description. MALE. Body length 4.0 mm. Eye bare; postocular setae in one row, slender and curved anteriorly, occipital setae situated behind the postocular setae on vertex and in one row; fronto-orbital plate and parafacial with grayish-silvery pollinosity; frons at narrowest point slightly narrower than the distance between outer margins of posterior ocelli, about 2/3 as wide as postpedicel; frontal vitta black, linear at narrowest point; frontal setae 7 to 9, stout, nearly reaching ocellar triangle, the gaps between them without setulae; orbital setae absent; parafacial bare and narrow, at middle about 2/5 of width of postpedicel; antenna black, postpedicel about 1.5x as long as wide, arista black and ciliated, slightly swollen in basal part, the longest individual hairs shorter than aristal base; epistoma not projecting beyond vibrissal angle, vibrissal angle behind frontal angle in profile; subvibrissal setulae in one row, lateral of it with 2 or 3 fine setae; gena and genal dilation with black setulae, upper margin of gena without upcurved setae; prementum with thin grayish pollinosity, slightly shining, about 2.3x as long as wide; palpus black, claviform, about as long as prementum. Thorax ground-color black, notum with thin dark brown pollinosity, without a distinct vitta; presutural acr biserial, slightly stout, prescutellar pairs stout, the distance between the 2 rows of acr narrower than the distance between rows of acr and dc; dc 2+3, ia 0+2, pra 2, the anterior one about 3/5 as long as posterior notopleural seta; notopleuron bare; proepisternal setae 2, proepimeral seta 1, with about 10 slender setulae around it; basisternum, proepisternum, anepimeron, meron and katepimeron bare; katepisternal setae 1+1, katepisternum without a ventral spine, with only some fine and curved setae; anterior spiracle brown, posterior spiracle dark brown; calypters brownish with yellow-brownish margin, the lower calypter slightly smaller than the upper one and not projecting beyond the upper one. Wing brownish; veins brown; wing-base of similar color to other parts of wing; tegula black; basicosta brown; costal spine inconspicuous; node of Rs bare on ventral and dorsal surfaces; vein R 4+5 straight, parallel to vein M 1+2 distally; crossveins not distinctly clouded; haltere brownish-yellow. Legs entirely black; fore coxa without a spine on anterior ventral surface; fore femur with a complete row of pv; fore tibia without ad and median p, and with only one stout preapical d; fore first tarsomere with several longish basal setae on ventral surface; mid coxa without a hook-like spine or spine-like seta; mid femur with 6 to 8 stout av in basal part, becoming gradually shorter and denser towards apex, with a gap in preapical part, 2 to 4 comb-like setae in distal part, and with a row of stout pv, slightly biserial in median part, with a gap in preapical part, with 4 or 5 comb-like setae in distal part, and with a row of slender p; mid tibia slightly swollen in distal half, with one ad and one pd in distal half, and with numerous slender setulae on ventral surface, the longest one about 3/4 of mid tibial width in distal part; mid first tarsomere without a basal tooth-like spine on ventral surface, and with only short basal clustered setulae; hind coxa bare on posterior surface; hind femur with only one stout av in preapical part, with 8 to 10 stout pv in distal half; hind tibia with one av, one ad, and one median d, and with 8 or 9 slightly erect median setae on posterior surface. Abdomen oval and flattened, ground-color black, with dense grayish-blue pollinosity; syntergite 1+2 and tergites 3-4 each with one dark broad median triangular vitta, tergite 5 with one dark median stripe in basal part; sternite 1 with setulae, sternite 5 broad (Fig. 2C); cercal plate longish, from ventral view, apex of cercal plate projecting, large and rounded, as broad as middle part of cercal plate and slightly broader than the basal part ( Fig. 2A); bacilliform process twisted (Fig. 2B); surstylus slender, hook-like at apex and pointed posteriorly ( Fig. 2A, B). FEMALE. Unknown.

Remarks.
The new species is attributed to the spathiophora-subgroup of the postica-group. It can be distinguished from a similar European species, Fannia stigi Rognes, 1982, by the following character states: mid first tarsomere with only short basal clustered setulae on ventral surface; hind femur with 8 to 10 stout pv in distal half; abdominal syntergite 1+2 and tergites 3-4 each with one dark broad median triangular vitta; apex of cercal plate projecting, large and rounded in ventral view ( Fig. 2A); bacilliform process twisted (Fig. 2B), while F. stigi Rognes mid first tarsomere with a basal tooth-like spine; hind femur with 4 or 5 stout pv in distal half; abdominal syntergite 1+2 and tergites 3-4 each with a dark median stripe; apex of ceral plate not projecting, half round in ventral view; bacilliform process not twisted.
Etymology. The specific name is derived from name of the type locality, Ningxia.

Fannia slovaca Gregor & Rozkošný, 2005
Fannia slovaca Gregor & Rozkošný, 2005: 519. Distribution. Palearctic: Slovakia. Rognes, 1982 Fannia stigi Rognes, 1982: 325. Fannia stigi: Wang, Li and Zhang 2011: 15. Fannia tigripeda: Xue, Wang and Li 2001Wang and Xue 2002: 57;Su and Wang 2004: 112 Description. MALE. Body length 5.0 mm. Eye bare; upper inner facets larger than the remaining facets; postocular setae in one row, short and neatly arranged, occipital setae absent; fronto-orbital plate and parafacial with grayish-silvery pollinosity; frons at narrowest point slightly wider than the distance between outer margins of posterior ocelli, about as wide as postpedicel; frontal vitta black, with grayish-silvery pollinosity, at narrowest point about as wide as fronto-orbital plate; frontal setae 5, stout, nearly reaching ocellar triangle, the gaps between them without setulae, orbital setae absent; parafacial bare, at middle about 1/2 as wide as postpedicel; antenna black, postpedicel about 1.5x as long as wide, arista ciliated, slightly swollen in basal part, the longest individual hairs shorter than aristal base; epistoma not projecting beyond vibrissal angle, vibrissal angle behind frontal angle in profile; subvibrissal setulae in one row, lateral of it with several setae; gena and genal dilation with black setulae, upper margin of gena without upcurved setae; prementum shining, without distinct pollinosity, about 2.0x as long as wide; palpus black, claviform, slightly longer than prementum. Thorax ground-color black, notum with dark brown pollinosity, without a distinct vitta; presutural acr biserial, slightly stout, only prescutellar pairs stout, the distance between 2 rows of acr narrower than the distance between rows of acr and dc; dc 2+3, ia 0+2, pra 2, the anterior one stout, about 2/3 as the length of posterior notopleural seta; notopleuron bare; proepisternal setae 2, proepimeral seta 1, lower part of proepimeral seta with one short setula; basisternum, proepisternum, anepimeron, meron and katepimeron bare; katepisternal setae 1+1, katepisternum without a ventral spine; spiracles brown; calypters brownish-yellow, the lower one slightly projecting beyond the upper one. Wing brownish; veins dark brown; wingbase of same color as other parts of wing; tegula dark brown; basicosta brownishyellow; costal spine conspicuous, about 2/3 of the length of crossvein r-m; node of Rs bare on ventral and dorsal surfaces; vein R 4+5 straight, veins M 1+2 and R 4+5 converging distally; crossveins not clouded; haltere brown. Legs entirely black, except knees yellow; fore coxa without a anterior spine on ventral surface; fore femur with a stout row of pv; fore tibia without ad and median p, with only one d and one v in apical part; fore first tarsomere with few longish basal setae on ventral surface; mid coxa without a hook-like spine or spine-like seta; mid femur with a row of stout and sparse av in basal half, becoming shorter and denser towards apex, with a gap in preapical part, 2 or 3 comb-like setae in distal part, a complete row of stout pv, slightly biserial in median part, and a row of slender p; mid tibia slightly narrowing in basal half, gradually swollen towards apex, about 2.0x as wide in distal part as wide in basal part, with one ad and one pd in distal half, and with numerous slender setulae on ventral surface, the longest one about 3/4 as long as mid tibial width in distal part; mid first tarsomere without a basal tooth-like spine on ventral surface, with only short basal clustered setulae; hind coxa bare on posterior surface; hind femur with only one stout av and 3 or 4 pv in preapical part; hind tibia with one av, one ad and one d. Abdomen long and flattened, ground-color black, with grayish-brown pollinosity; syntergite 1+2 and tergites 3-4 each with an inverted T-shaped dark mark, each tergite with stout lateral marginal setae; sternite 1 broad, with 4 long setae on each lateral margin, sternites 2 to 4 narrow, with long setulae, sternite 5 with slightly dense setae in posterior margin; cercal plate longish, from ventral view, cercal plate slightly indented in each lateral margin, middle part of cercal plate strongly broader than the apex and the basal part ( Fig. 3A); bacilliform process curved (Fig. 3A, B); surstylus slender, curved at apex and pointed posteriorly (Fig. 3A, B). FEMALE. Unknown.

Remarks.
The new taxon is similar to the holarctic species F. aethiops Malloch, 1913 but differs from it for the following character states: frontal setae only 5; anterior pra about 2/3 as long as posterior notopleural seta; sternite 1 with 4 long setae on each lateral margin; in ventral view, cercal plate broadest in median part, slightly indented in each lateral margin (Fig. 3A); bacilliform process curved (Fig. 3A & B), while F. aethiops Malloch frontal setae 9; anterior pra about 1/2 as long as posterior notopleural seta; sternite 1 with 1-2 long setae on each lateral margin; in ventral view, cercal plate not indented in each lateral margin; bacilliform process not curved.
Etymology. This specific name refers to the similarity between the new species and F. aethiops Malloch.