An unusually rich scuttle fly fauna (Diptera, Phoridae) from north of the Arctic Circle in the Kola Peninsula, N. W. Russia

Abstract 64 species of Phoridae, in 6 genera, are reported from the Kola Peninsula, north of the Arctic Circle. The new species Megaselia elenae and Megaselia kozlovi are described. 33 species of Megaselia, only known from females, are given code numbers. Keys to the species of all the females of Megaselia and Phora are provided; and also a key to the males European Megaselia species with a notopleural cleft.


Introduction
The only published record of scuttle flies (Diptera: Phoridae) from the Kola Peninsula refers to Megaselia opacicornis Schmitz parasitizing the pupae of the leaf beetle Chrysomela lapponica (L.) (Chrysomelidae) . The town of Monchegorsk (67°55'N, 32°50'E) is situated north of the Arctic Circle. It is the centre for the smelting of copper and nickel in the Kola Peninsula and is one of the most polluted towns in the Russian Federation (Kozlov et al. 2009;Eeva et al. 2012). During 2009 than a lower SA but the longest subequal to latter, and as many hairs. Labrum yellowish brown and about half as wide as a postpedicel. Labella coloured as palps but with light brown bands on upper sides towards margins and with very few short spinules below. Thorax brown. Two notopleural bristles and a cleft in front of these, which ends just before reaching a c-shaped ridge across its path. Mesopleuron bare. Scutellum with an anterior pair of small hairs and a posterior pair of bristles. Abdominal tergites brown with small hairs except for clearly longer hairs at rear of T6. Venter brown, and with a few hairs on segments 3-6, those at rear of segment 5 being longer, and those at rear of T6 being clearly the longest. The (damaged) hypopygium is brown, with a pale brown anal tube, which is clearly longer than the length of the dorsal face of the epandrium. Each side of the latter 16-18 hairs, which are longer and stronger anteriorly but are smaller and weaker behind, and with a strong bristles (about 0.13 mm long). The hairs of the proctiger are as long and clearly thicker than hairs of the cerci. The left lobe of the hypandrium is pale grey, about 0.06 mm long, and lacking micritrichia. The right lobe is also pale grey and bare, but is only 0.02 mm long (and only 0.03 mm wide at its base). With 4 rectal papillae. Legs yellowish brown with the hind femora being the darkest and the front legs the more yellowish. Fore tarsus with a posterodorsal hair palisade on segments 1-5 and 5 a little longer than 4. Dorsal hair palisade of mid tibia extends about two thirds of its length. Hairs below basal half of hind femur clearly longer than those of anteroventral row of outer half, which are themselves long (Fig. 1). Hind tibia with 10 differentiated posterodorsal hairs and spinules of apical combs simple. Wings 1.4 mm long. Costal index 0.54 Costal ratios 3.1 : 2.7 : 1. Costal cilia (of section 3) 0.13-0.14 mm long. Hair at base of vein 3 as small as costal cilium at base of costa. With 3 axillary bristles, all shorter than costal cilia. Sc not reaching R1. All veins yellowish grey, with thin veins 4-6 being darkest. Membrane lightly tinged grey (just evident to naked eye when viewed against a white background). Haltere knob yellow.
Type material. Holotype ♂, RUSSIA, Kola Peninsula, near Monchegorsk, in yellow trap, 26.vi-6.vii.2010, M. Kozlov (UCMZ, 17-89). Megaselia haraldlundi Disney: YT -1 female. Megaselia humeralis (Zetterstedt): BT -1 male. This species parasitizes the pupae of the leaf beetle Chrysomela lapponica (Chrysomelidae) (Disney and Zvereva 2008). Megaselia immodensior Disney: BT -1 male, 1 female. YT -1 male. This species is a little variable and the specimens from the Kola Peninsula extend the range of variation a little. For example the costal index of the male is only 0.42, but in the type series it is more than 0.44 (Buck and Disney 2001). The CI of the female from the Kola Peninsula is 0.45 to 0.46. Megaselia fallobreviseta Disney: BT -3 females. YT -5 males, 2 females. This is sibling species of M. breviseta. The males are almost indistinguishable but the females of the two species are readily distinguished (Disney 2011b). It has been reared from the caterpillar tents of an ermine moth (Yponomeuta sp.) in Germany. Megaselia fuscovariana (Schmitz): BT -1 male, 1 female. YT -1 male, 1 female.

Megaselia kozlovi sp. n.
http://zoobank.org/33869855-A189-4460-B780-E546125885AD http://species-id.net/wiki/Megaselia_kozlovi Figs 3-7 Diagnosis. In the key to the males of the species of the British Isles (Disney 1989) the males will run to couplet 245, Lead 1, where one is directed to return to couplet 241. It runs out there to Lead 1, but the species of this lead is covered by a revision of a group of species (Buck and Disney 2001) from which the new species is immediately excluded by having 3, not 2, bristles on the notopleuron. Furthermore, the small anterior pair of hairs on the scutellum contrast with the bristle like anterior scutellars of the species it most resembles in this complex.
Etymology. Named for its collector Mikhail Kozlov. Description. Male. Frons brown, clearly broader than long, with 30-42 hairs and very dense but very fine microtrichia. Supra-antennal bristles (SAs) unequal, the lower pair being about as long as the longest (apical) bristle of the palp but less robust than it. The antials lower on frons than anterolaterals, and more than twice as far from upper SAs as either is from an AL bristle. Pre-ocellars slightly closer together than either is from a mediolateral bristle, which is very slightly higher on frons. Cheek with 2-3 short bristles and jowl with one long and one short bristle. The subglobose postpedicels brown, without SPS vesicles. Palps yellow, at most a third as broad as postpedicel but about 1.4 times as long as breadth of latter, with 5-8 bristles, 3-4 being long and the rest short, and 1-3 hairs. Labrum pale yellow and about 0.8 times as wide as a postpedicel. Labella a little paler than palps, with only a few short spinules below but with several pale teeth along their inner edges.. Thorax brown. Three notopleural bristles and no cleft in front of these. Mesopleuron bare. Scutellum with an anterior pair of small hairs and a posterior pair of bristles. Abdominal tergites brown with T6 being longest and with longer hairs at its rear margin than on the rest of the tergites. Venter grey, and with fine hairs on segments 3-6. Hypopygium brown, with a light brown anal tube, and as Figs 2-3. Legs with yellowish brown hind femora and otherwise dusky yellow (apart from the largely brown mid coxae). Fore tarsus with segments 1-3 somewhat stout and with at least one row of hairs below each reduced to short pale spinules. A posterodorsal hair palisade on segments 1-4 and 5 about as long or slightly shorter than 4. Dorsal hair palisade of mid tibia extends about two thirds its length. Hairs below basal half of hind femur longer than those of anteroventral row of outer half. Hind tibia with 11-12 differentiated posterodorsal hairs and spinules of apical combs simple. Wings 1.3-1.4 mm long. Costal index 0.48-0.50. Costal ratios 3.0-3.6 : 2.0-2.4 : 1. Costal cilia (of section 3) 0.07-0.08 mm long. No hair at base of vein 3. With 2 axillary bristles, the outer being a little longer than costal cilia. Sc not reaching R1. Thick veins and vein 7 yellowish grey, thin veins 4-6 grey. Membrane tinged grey (evident to naked eye when viewed against a white background). Haltere knob yellow.
Female. Head similar to male except palps with 7-8 bristles, the longer ones being a little shorter than those of male, and with 3-7 hairs. Thorax as male. Abdominal tergites brown. T3-T7 as Fig. 4. Venter grey, and with hairs below segments 3-6. Sternite 7 an isosceles triangle tapering to an anterior point and with 4 longer hairs at its straight hind margin and at least as many smaller hairs further forward. The single lobe at rear of sternum 8 as Fig. 6. Cerci and epiproct as Fig. 5. With 4 rectal papillae. Furca not evident. Dufour's crop mechanism as Fig. 7. Legs similar to male except the front tarsus has segment 1-3 as slender as the rest, segment 5 is a little longer than 4 and 5 may or may not have a posterodorsal hair palisade. Wing as male except 1.4-1.6 mm long. Costal index 0.47-0.49. Costal ratios 2.8-3.9 : 1.5-2.5 : 1. Costal cilia 0.08-0.09 mm long. Otherwise it and haltere as male. Two females were gravid, one with 5 eggs and the other with 6. These eggs measured 0.3-0.4 mm long and 0.16-0.17 mm wide.
The following species are only known in the female sex and are given code numbers only until they can be linked to their males. The sequence of numbers is incomplete as some females were subsequently linked to their males.
YT -94 females, which was 27.3% of the phorids in the yellow traps. None were gravid and one had amorphous detrital material in the gut. Megaselia species 6: BT -6 females. One with 2 relatively large eggs, that were 0.74 mm long and 0.28 mm wide (HF = 0.91 mm long). There was no evidence of feeding on carrion fluids. Megaselia species 7: BT -2 females. None was gravid and there was no evidence of feeding on carrion fluids. Megaselia species 8: BT -11 females. YT -8 females. None were gravid and there was no evidence of feeding on carrion fluids. Megaselia species 10: BT -7 females. YT -1 female. None were gravid but one had fungus spores in the crop. Megaselia species 11: BT -1 female. With amorphous detrital material in the gut. Megaselia species 12: BT -1 female. With amorphous detrital material in the gut. Megaselia species 13: BT -1 female. Megaselia species 16: BT -29 females. YT -7 females. Most had amorphous detrital material in the gut and in one case this included short, thick walled, fungus bodies. One had 2 mature eggs remaining, the rest of the batch evidently having been deposited. Megaselia species 17: BT -2 females. Megaselia species 18: BT -5 females. Three with amorphous detrital material in the gut, one of which included a few spindle-shaped fungus spores. Megaselia species 19: BT -20 females. Three with amorphous detrital material plus fungus spores in the gut, the spores being round in one case and spindle shaped in two. A few pollen grains were present in guts of two specimens. One with 24 half developed eggs. Megaselia species 20: BT -3 females. Megaselia species 21: BT -2 females. Megaselia species 24: BT -1 female, with dark amorphous material in the gut.

Concerning the genus Phora
The recognition of the species in this genus is based on the males, with particular attention to the hypopygium. In his keys to the Palaearctic species, Schmitz (1953Schmitz ( , 1955 divided the species into three groups. Section I species have 2 or 3 anterior bristles on the basal half of the hind tibia. Those of Section II have only 1 such bristle on the hind tibia, and 2 anterior bristles on the basal half of the mid tibia. The species of Section III have only 1 of each of such bristles on the mid and hind tibiae. However, P. dubia in Section I (under a synonym, loc. cit., 1955: 342) has 1 or 2 bristles on its hind tibia, and in some specimens there is 1 on one leg and 2 on the other. Likewise P. stictica in Section II occasionally has 2 bristles on the hind tibia and only 1 bristle on the mid tibia; and P. artifrons in the same section likewise sometimes has only 1 bristle on the mid tibia. Such variation has to be taken into account when trying to match up females with their males. In addition there is evidently some sexual dimorphism in these bristle number differences. For example for some P. atra (Meigen) males I have obtained mating there were 4 or 5 dorsal bristles on the mid tibia, but only 2 or 3 on those of their female partners. Furthermore, some males of this species occasionally have 2 anterior bristles on at least one mid tibia; which means they would be in Schmitz's Section II instead of Section III. One specimen attributed to P. holosericea has no anterior bristles on the mid tibiae. Other variation occurs with respect to colour, such as the costa, the thin veins and the wing membrane (including the extent of the regions devoid of microtrichia), and the front tibia and tarsus. As none of the females were gravid, apart from one with immature eggs, some of the paler specimens were probably only recently emerged from their pupae and were not fully darkened. The result of these variations is that females are still poorly known in this genus. However, Cook and Mostovski (2002) have shown the use of 16S mitochondrial sequences in linking unknown females to their correct males, and then correlating these molecular signatures with small morphological differences. In the collections from the Kola Peninsula only five species represented by males were obtained. I have therefore identified the females on the assumption that only these five species needed to be considered. A tentative key to the species of females from the Kola Peninsula is given below.
The female of this species was only briefly described by Schmitz (1943) and without any figures. The abdominal sternite 7 was described thus "anscheinend gross, an den Seiten weit hinaufreichend". Figs 8-9 illustrate this.

Key to Megaselia females of species recorded in the Kola Peninsula
This key provides a preliminary sorting only. Identification requires checking out the details given under the brief description of each species.
Note: Variable species are keyed both ways at several couplets

18
Mesopleuron with hairs only gradually increasing in size towards rear margin ...19 -Mesopleuron with small hairs contrasting strongly with the single bristle at rear margin. (Abdominal tergites 5 to 8 as Fig. 10)  T3 with a concave hind margin and typically shorter than T4 (Fig. 10). (Dufour's crop mechanism as Fig. 11)  Labrum less massive (e.g. Fig. 22). Postpedicels uniformly brown and with SPS vesicles. Vein 3 with minute hair (shorter than width of vein) or without hair. Hairs below hind femur longer than those of a-v row of outer half ...51 50 With more than 30 hairs on segments 3 to 5 of abdominal venter as well as many on 6, which has longer hairs at rear margin. Furca not evident. Lobes at rear of sternum 8 as  -With less than 15 hairs on segments 3-5 of venter. A strongly sclerotised furca present (Fig. 25). Lobes at rear of abdominal sternum 8 rounded as Fig. 24 Fig. 15. Lobes at rear of S8 and hypoproct as Fig. 13. Internal tubular organ as Fig. 17. Furca as Fig. 16  The S8 lobes are conspicuously brown (Fig. 23). (Labrum as Fig. 22)  Hairs below basal half of hind femur longer than those of the anteroventral row in outer half. A single lobe with many hairs at rear of abdominal sternum 8 (Fig. 6) Haltere knob yellow. Postpedicels lack SPS vesicles. Hind femur yellow with brown tip and hairs below basal half of hind femur are longer than those of the anteroventral hairs of outer half. With a strongly sclerotised furca    Fig. D fig. 393. Palps with short bristles and as B fig. 1)     Cerci at least twice as long as broad (B fig. 17 and D fig. 400). Wing with at least 3 axillary bristles and costal cilia ( The separation of the females of P. pubipes Schmitz and P. holosericea Schmitz has been based on minute differences in the distribution of microtrichia on the hind trochanters and microsculpture on the hind femora. However, there are probably better differences in the proboscis. At present I only have two poor females of P. holosericea that were procured mating with males. Until better voucher specimens of both species, and other species of Phora, are available for both these species reliable differences cannot be proposed with any confidence. Apart from mating pairs, reared series or specimens for which molecular barccodes have been determined are required.

Discussion
The number species recorded above is far larger than expected. Only six species are known to occur in Greenland, with only three established north of the Arctic Circle (Disney, in press). For Iceland, which lies immediately south of the Arctic Circle, 11 species have been recorded (Prescher et al. 2005). For the British Isles more than 340 species have been recorded so far, with at least 80 of these being recorded in my suburban garden in Cambridge. In the Antarctic one species being accidentally introduced by man has been reported (Nickolls and Disney 2001) and a second species introduced by man has become established on islands in the South Atlantic Ocean to the north of the Antarctic Circle (Hänel andDisney 2006, Jones et al. 2003). It would seem that the impoverished faunas of these situations is due more to their remoteness than to their high latitudes. By contrast the Kola Peninsula is attached to the mainland of Europe.