A Review of the Lonchaea Fraxina Group of Species (Diptera: Lonchaeidae) with the Description of a New Species

Ent. Tidskr. 135 (2014) Review of the Lonchaea fraxina-group A review of the Lonchaea fraxina group of species (Diptera: Lonchaeidae) with the description of a new species

Iain MacGowan

MacGowan, I.: A review of the Lonchaea fraxina group of species (Diptera: Lonchaeidae) with the description of a new species. [Revision av Lonchaea fraxina-gruppen (Diptera: Lonchaeidae) inklusive beskrivning av en ny art.] – Entomologisk Tidskrift 125 (4): 179-186. Uppsala, Sweden 2014. ISSN: 0013-886x.

The status of species within the Lonchaea fraxina group are reviewed and one new species Lonchaea angelina sp. nov. is described. A key with accompanying illustrations is provided for males of species within the group. The holotype specimen of L. stigmatica Czerny, 1934 is re-described.

Iain MacGowan, Scottish Natural Heritage, Battleby, Redgorton, Perth, PH1 3EW. Scot- land. E-mail: [email protected].

Introduction L. stigmatica and L. hirticeps Zetterstedt, 1837. Within the genus Lonchaea Fallén four species, L. stigmatica was described, and is at present still Lonchaea fraxina MacGowan & Rotheray, 2000, only known, from a single female specimen col- L. iona MacGowan, 2001, L. spicata MacGowan, lected in the Russian Far East, north west of Vlad- 2008 and L. stigmatica Czerny, 1934, are unique- ivostok. Although the type specimen originated ly distinguished by the presence of hairy eyes, from the extreme east of the Palearctic this name multiple rows of anterior genal setae, dark fringes was used by subsequent authors for species oc- on the calypteres and entirely black legs. These curring in the European fauna. Further confusion species are referred to in this paper as belonging arose when Czerny (1934) included L. stigmatica to the “Lonchaea fraxina group”. They can all in his key to Lonchaea under the section on spe- show variation in the number of setae or setulae cies with bare eyes when in fact the eyes are pi- on the proepimeron, the presence and number of lose (see revised description below). setulae on the orbital plates and scutellar disc and In his key to the British Lonchaeidae Collin in the density and length of eye hairs; all features (1953) identified only one species with charac- which can make species level identification diffi- ters of the L. fraxina group which he mistakenly cult. The discovery of a new species belonging to called L. hirticeps. In the accompanying text this group has led to a re-examination of the male description he refers to earlier descriptions by genitalia and, as a result, further distinguishing Zetterstedt and Czerny noting that “this species characters to separate the species have been iden- evidently requires further study based on more tified. material”. Hackman (1956) produced keys to the Lon- Background chaeidae of eastern Fennoscandia. No doubt in- This small group of species has always proved fluenced by Collin’s earlier work he also listed taxonomically difficult. Previous keys to Euro- L. hirticeps as the only species with characters pean Lonchaeidae have confused the identity of of the L. fraxina group. However in the text de- 179 Iain MacGowan Ent. Tidskr. 135 (2014) scription he also refers to the confusion with the scribed from a specimen collected in Greece has name of this species and noted that the holotype now been found more widely in Europe. The needed to be re-examined. holotype of this species has scattered pale hairs The situation was clarified in part by McAl- on the eyes but other specimens examined have pine (1958) who examined the Zetterstedt types bare eyes. It does however consistently exhibit of L. hirticeps and re-described them as having the other characters of the group including hav- a single row of anterior genal setulae. McAlpine ing a phallus with a short, sinuous apical section also stated that the L. hirticeps specimens de- This paper adds a new species to this group scribed by Collin (1953) belonged to a different seeks to provide clear distinguishing characters species. However the implications of this paper based on the male genitalia. were not fully translated into the European liter- The figures of male genitalia included within ature and the status of the species called L. hirti- this paper follow the standard orientation ad- ceps by Collin was unresolved. Indeed Kovalev opted in the Manuals of Palearctic and Nearctic and Morge (1984) still listed L. hirticeps as a Diptera, not those of MacGowan & Rotheray British species whilst noting that “central Euro- (2008). pean specimens require confirmation”. Morge (1963) provided a key to the Europe- Systematics an Lonchaea species. Taking note of McAlpine (1958) he correctly placed L. hirticeps but, in the Lonchaea Fallén, 1820 section of the key relating to species with char- Lonchaea angelina sp. nov acters of the L. fraxina group the only species Male. listed is L. stigmatica. Morge had obviously ex- Head: Compound eyes hairy, hairs pale, mod- amined the Holotype of L. stigmatica and noted erately dense, as long as combined diameters of the hairy eyes; he remarked that the intercos- three omatidia. Frontal and interfrontal setulae tal space is “almost four times longer than the numerous, as long as orbital seta, orbital plates cross-vein”. This measurement probably related with setulae in addition to single seta. Antennae to the overall length of crossvein rm rather than entirely black, first flagellomere 1.5x longer than the internal length, that is the length of rm from broad; arista black, microscopically pubescent. the lower margin of vein R4+5 to the upper mar- Genal setulae forming multiserial rows anteri- gin of vein M1 which is used in this paper. orly. Shtakel’berg (1967) in his key to the Lon- Thorax: Thoracic disc subshining black with chaeidae of Russia and Europe followed Morge dense setulae as long as orbital seta. Anepimeron (1963) and the only species listed with char- covered with numerous setulae as long as orbital acters of the L. fraxina group is L. stigmatica. seta, no obvious differentiated row of strong an- This name was still being applied in the Euro- terior or posterior setae. Katepisternum with one pean fauna by Maca (1999) who included it in a weak seta near dorsal margin not greatly differen- checklist of the German fauna. tiated from the other setulae on sclerite, scattered MacGowan & Rotheray (2000) examined setulae present anterior to this seta, none poste- specimens of L. hirticeps cited by both Collin rior. Proepimeron with two setae, one propleural. (1953) and Hackman (1956), and compared Scutellar disc slightly brownish when compared them with the descriptions of previous authors to thorax, bare, margin with two setulae between and with their own extensive reared mate- apical and lateral setae, two between apical setae, rial. This led them to describe a new species, these slightly creeping on to disc. Legs entirely L. fraxina occurring in the British Isles and in black. central Europe. L. iona MacGowan, 2001 was Wings: Calyptrae greyish with a long, dark later added to the group (MacGowan 2001) and fringe. Wings clear with whitish veins. Intercos- in their Handbook to the British Lonchaeidae tal space, (area of costa between insertion of MacGowan & Rotheray (2008) provide a key veins Sc and R1) with length to depth ratio 3 : 1 which distinguishes both of these species. (measurement as in Fig. 4d). Ratio of length of A further species, L. spicata originally de- intercostal space to internal length of rm (mea- 180 Ent. Tidskr. 135 (2014) Review of the Lonchaea fraxina-group a Anterior b Anterior Epiandrum

Epiandrum Surstylus

Surstylus Ventral Ventral

Cercus

Posterior Posterior c

Figure 1. Lonchaea angelina sp. nov. – a) Left lateral view of epandrium and associated structures, – b) Left lateral view of inner surface of surstylus, – c) Left lateral view of phallus. sured from the lower margin of vein R4+5 to the Lonchaea species. Phallus two segmented, basal upper margin of vein M1) 5 : 1. When the line of part rectangular and rather broad, apical part S- crossvein r-m is extended to costa it reaches it at shaped. the insertion of Sc. Wing length 2.8mm. Holotype male: SWEDEN: Värmland, Munk- Male genitalia: Fig. 1. Epandrium in lateral fors kommun, Ransäter, Ransberg Herrgård, old view wider than high, bearing a row of setulae mixed deciduous forest in stream ravine. N 59º along posterior margin and a group of setulae at 47’ 25.59” E 13º 24’ 54.61” 26.iv - 22.v.2005 posterioventral angle. Cerci rather rectangular, (=coll. event ID 1383) Leg. Swedish Malaise not heavily chitinised, bearing setulae along the Trap Project. Deposited in Swedish Natural His- mid-line and at apex. Surstyli projecting ventral- tory Museum. ly beyond the shell of the epandrium with a row Paratype: GREECE: Kerkini Site, Malaise of strong setae on margin, a slight posterioven- trap, N 41°13’47, E 23°21’ 71, 4-10.iv.2005, 1 tral projection evident. Inner surface of surstyli male, leg. G. Ramel. Deposited in National Mu- with a single row of 6 very strong setae, area be- seums of Scotland. tween this row and the ventral margin with only Etymology: the species is named after my a few shorter setae, a spherical process covered partner Angela. with small spicules present anterior to the single Differential diagnosis: The single row of row of strong setae, this process arises from and very strong setulae on the inner surface of the forms part of the surstylus, it seems to be unique male surstyli and the spherical spiculate process to L. angelina with no similar analogue in other are the main characters distinguishing this spe- members of the group or as far as I know in other cies from its close associates. 181 Iain MacGowan Ent. Tidskr. 135 (2014) a b

Figure 2. Lonchaea fraxina MacGowan and Rotheray, 2000. – a) Left lateral view of epandrium and associated structures, – b) Left lateral view of inner surface of surstylus, – c) Left lateral view of phallus.

Both specimens were collected in alcohol in is positioned at 90º to the vertical, facing left. a Malaise trap and are now mounted and micro- The right foreleg and left hind leg are missing. pinned with dissected genitalia cleared in KOH and retained in gylcerin in a microvial attached Holotype female to the mounting pin below the specimen. As a Head: Eyes with dense covering of short hairs, result of being collected in alcohol the speci- each as long as width of an ocellus, light co- mens are slightly shrivelled. loured (but this might just be an ageing effect). Genae wide anteriorly with multiserial black Re-description of Lonchaea stigmatica Cz- setulae. Frons wide, at level of ocellar triangle erny, 1934 wider than width of an eye, frontal and inter- The original description of the Holotype female frontal setulae short and rather sparse, at most provided by Czerny (1934 p. 20) extends to about half as long as orbital seta. Orbital plates just over 5 lines. As the species clearly belongs bare. Right orbital seta missing as are the ocellar within the L. fraxina group the opportunity is setae. Antennae entirely black, relatively large taken here to provide a fuller description. The for such a small species, almost extending to Holotype specimen from the Naturhistorisches mouth margin, postpedicellus 1.5x as long as Museum, Vienna, was examined. A stout pin deep, arista relatively short approximately 40% passes through the sides of the thorax; the head of its length extending beyond apex of flagel- 182 Ent. Tidskr. 135 (2014) Review of the Lonchaea fraxina-group a b

Figure 3. Lonchaea iona MacGowan, 2001: – a) Left lateral view of epandrium and associated structures, – b) Left lateral view of inner surface of surstylus, – c) Left lateral view of phallus.

lomere, bearing microscopic setulae. surement as in Fig. 4d). Ratio of length of inter- Thorax: dorsum slightly dusted. Proepimeron costal space to internal length of crossvein rm and proepisternum with one seta. Anepisternum (measured from the lower margin of vein R4+5 with most setae missing. Katepisternum with to the upper margin of vein M1) 8 :1. When the two dorsal setae very close together on right side line of r-m is extended to costa it reaches it at a (probably an aberration) the normal one seta on point basal to the insertion of S1. left, no setulae posterior to these but with 4-5 Type locality: Tigrovaja, UssuriGeb. Primor- setulae anteriorly, one or two along anterior sky krai, Russian Far East. margin of the sclerite. One setulae in notopleu- ral depression on right side, left side obscured Additional descriptive information on the by pin. Scutellum bare on dorsum, margin with characters of the male genitalia of species three small setulae between apical setae in two within the L. fraxina group horizontal rows, two between laterals on left Although within the male genitalia figured in side and one on right, these setulae short, api- this paper the cerci are distinguishable between cals approx. 25% length of apical setae. Legs species they are not used here as a specific char- entirely black. acter due to the fact that this soft tissue can vary Wings: Calypteres dark with dark fringe. in shape according to the way in which the spec- Wing with all veins rather yellowish. Intercostal imen has been dried, stored or prepared. space, (area of costa between insertion of veins Sc and R1) with length to depth ratio 4 :1, (mea- 183 Iain MacGowan Ent. Tidskr. 135 (2014) a b

Figure 4. Lonchaea spicata MacGowan, 2008: – a) Left lateral view of epandrium and associated structures, – b) Left lateral view of inner surface of surstylus, – c) Left lateral view of phallus, – d) Central section of wing showing length and depth measurement points for the intercostal space and position of crossvein r-m.

Lonchaea fraxina MacGowan & Rotheray, including the posterior projection and the area 2000 dorsal of the row of setae. Phallus with a broad Male genitalia; Fig. 2. Surstylus; in lateral view basal section and small slightly sinuous apical with a rounded posterior projection extending section. beyond the shell of epandrium, inner surface with a double / triple posterior-anterior row of Lonchaea iona MacGowan, 2001 between 14 and 20 strong setae, between these Male genitalia; Fig. 3. Surstylus; in lateral view and the ventral margin a scatter of approximate- usually with posterior and ventral margins ex- ly 6-8 setae, moderately dense fine setulae cov- tending beyond shell of epandrium, posterior ering most of the inner surface of the surstyli surface flat, extending ventrally to form a small 184 Ent. Tidskr. 135 (2014) Review of the Lonchaea fraxina-group ventral projection, inner surface with approxi- being approximately eight times as long as the mately 8 well scattered, rather short setae, oth- internal length of crossvein r-m which itself is erwise with scattered small setulae. Phallus with in line with a point on the costa just before the broad basal section and distinctly sinuous apical insertion of vein Sc section. The L. fraxina group seems to be exclusively Palearctic; there are no similar described North Lonchaea spicata MacGowan, 2008 American species, the most closely related spe- Male genitalia; Fig. 4. Surstylus; in lateral view cies, Lonchaea nebulosa McAlpine & Munroe usually with posterior and ventral margins extend- 1968, has hairy eyes, dark calypteres and fringes ing beyond shell of epandrium, stout spine-like and all black legs but the anterior genal setulae setae usually visible extending beyond ventral are uniserial. margin; inner surface with a scatter of approximately 20 strong setae concentrated on ventral Key to the Lonchaea fraxina group portion, fine setulae almost entirely confined to 1. Wing; ratio of length of intercostal space to internal a conspicuous raised area in the posterio-dorsal length of crossvein rm 8 : 1, (measurement as in quadrant of the surstylus. Phallus with basal sec- Fig. 4d), extended line from crossvein rm reaching tion much narrower than in L. fraxina and L. costa basal to insertion of Sc, ...... iona, apical segment larger and more sinuous...... stigmatica Czerny, 1934. –. Ratio of length of intercostal space to internal length of crossvein rm at most 6 : 1, extended line from Discussion crossvein rm reaching costa at, or distal to, inser- It has been difficult to distinguish the males of tion of Sc...... 2 L. fraxina group due similarity of external char- 2. Male genitalia; inner surface of surstylus with a dis- acters and the intra-specific variation in chaeto- tinct row of strong setulae parallel to the ventral mar- taxy. Taxonomic characters on the inner surface gin (Figs. 1, 2) ...... 3 of the male surstylus, in particular the number, –. Inner surface of surstylus with only scattered setulae size and distribution of setae and setulae, have (Figs. 3, 4) ...... 4 been found to provide a more satisfactory way 3. Strong setulae forming a single row of approximate- of distinguishing between the males. ly 6, a small spiculate rounded process lying anterior to these (Fig.1b). Proepimeron with two setae, It is now clear that there are five species in the scutellar disc bare. Intercostal space length to depth L. fraxina group. Two (L. fraxina and L. iona) ratio approx. 3 :1...... angelina sp.nov. are relatively well known in western and central –. Strong setulae forming double or triple row of be- Europe, one (L. angelina) is known from the ma- tween 14 and 20, no rounded small spiculate anterior terial described here, and one (L. stigmatica) is process (Fig. 2b). Proepimeron usually with more known only from the female holotype captured than three setae, scutellar disc usually with setu- in the Russian far east. L. spicata occurs sporadi- lae. Intercostal space length to depth ratio in range cally across western Europe. of 4-6 : 1 ...... The status of L. stigmatica remains unsatisfac- ...... fraxina MacGowan & Rotheray, 2000. tory and, until more material with an associated 4. Inner surface of surstylus with only a few scattered spinules, without an anterior setulose raised area male is found, it is difficult to accurately deter- (Fig. 3b). Basal section of phallus distinctly broad- mine its relationship to the western Palearctic er than apical section (Fig. 3c). Proepimeron with species. For example the length of crossvein rm one or occasionally two/three setae. Intercostal may have a variability that could be related to space length to depth ratio in range of 2.8-3.3 : 1 .. sex or other environmental causes and is based ...... iona MacGowan 2001 on only one specimen. If males are found they –. Inner surface of surstylus with approximately 20- should be able to be distinguished by having the 30 scattered spinules, a finely setulose raised area orbital plate bare apart from the orbital seta, one lying anterior to these (Fig. 4c). Phallus with basal setulae on the proepimeron, disc of the scutel- section only slightly wider than apical section (Fig. lum bare with the margin bearing only a few 4b). Proepimeron with one or occasionally two setae. Eyes often bare. Intercostal space length to short setulae. The wing also holds important depth ratio 2 :1 ...... spicata MacGowan, 2008. features with the length of the intercostal space 185 Iain MacGowan Ent. Tidskr. 135 (2014) Acknowledgements books for the Identification of British Insects, Vol. 10 I thank Kajsa Glemhorn (Swedish Malaise Trap Proj- (15). 142pp. Royal Entomological Society, London. ect) for the provision of material for this study and McAlpine, J.F. 1958. Identities of Lonchaeid Flies de- staff at the Naturhistorisches Museum,Vienna for the scribed by Zetterstedt, with notes on Related Spe- loan of the holotype of Lonchaea stigmatica. cies (Diptera). – The Canadian Entomologist 90: 402-418. Morge, G. 1963. Die Lonchaeidae und Pallopteridae Os- References terreichs und der angrenzenden Gebiete. 1. Teil Die Collin, J.E. 1953. A revision of the British (and notes on Lonchaeidae. – Naturkundliches Jahrbuch der Stadt other) species of Lonchaeidae (Diptera). – Transac- Linz 9: 123-312. tions of the Society for British Entomology 11: 181- Shtakel’berg, A.A. 1967: Chapter 75 Family Lonchaei- 207. dae. – In: Keys to the insects of the European USSR, Czerny, L. 1934. Family 43. Lonchaeidae. – In: Lindner, G. Ya. Bei-Bienko (ed.) 5(1-2): 358-373. Diptera E. (ed.): Die Fliegen der Palaearktischen Region. and Siphonaptera. Smithsonian Institution Libraries Band 4 (43). Schweizerbart, Stuttgart, 40 pp. and the National Science Foundation, Washington, Hackman, W. 1956. The Lonchaeidae (Dipt.) of Eastern D.C. Fennoscandia. – Notulae Entomologicae 36: 89-115. Kovalev, V.G. & Morge, G. 1984. Family Lonchaei- dae. – In; Soós, Á. and Papp, (eds.). Catalogue of Svensk sammanfattning Palaearctic Diptera 9, Micropezidae – Agromyzidae: Bland stjärflugorna (Lonchaeidae) finns ett art- 247-259. Elsevier. rikt släkte, Lonchaea, där de flesta arter lever i Maca, J. 1999. Lonchaeidae. – In: Schumann, H., Bähr- ved. I denna artikel går författaren igenom de mann, R and Stark, A. (eds.). Entomofauna German- fem arter i detta släkte som karaktäriseras av ica 2. Checkliste der Dipteren Deutschlands. Studia bl.a. håriga ögon och helsvarta ben och som Dipterologica. Supplement 2: 158-159. MacGowan, I. 2001. A new species of Lonchaea (Dip- han kallar L. fraxina-gruppen. Arterna är gan- tera, Lonchaeidae) from Andorra. – Boletin de la ska svåra att särskilja och författaren går igenom Asociacion Espanola de Entomologica 25 (3-4): den stora förvirring som har rått runt dem i lit- 63-66. teraturen. Här publiceras nya artskiljande karak- MacGowan, I. 2008. Two new species of Lonchaeidae tärer på hanarnas genitalier. Undersökningarna (Diptera: Schizophora) from Greece. – Studia Dip- visar också att det finns en hittills obeskriven art, terologica 14 (2): 285-288. MacGowan, I. & Rotheray, G.E.R. 2000. New species, som i artikeln ges namnet Lonchaea angelina additions and possible deletions to the British Lon- n.sp. Namnet är givet efter författarens partner. chaea Fallen (Diptera, Lonchaeidae). – Dipterists Typexemplaren har fångats i Munkfors, Värm- Digest 7: 37-49. land i det svenska Malaisefälleprojektet och i MacGowan, I. & Rotheray, G.E. 2008. British Lonchaei- Grekland. dae. Diptera, Cyclorrhapha, Acalyptratae. – Hand-

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