Dicranomyia (Dicranomyia) mitis ( Meigen, 1830 )

Starý, Jaroslav & Stubbs, Alan E., 2015, Five species under Dicranomyia (Dicranomyia) mitis (Meigen, 1830) (Diptera, Limoniidae), Zootaxa 3964 (3), pp. 321-334 : 323-326

Dicranomyia (Dicranomyia) mitis ( Meigen, 1830)

Figs 1 , 6 , 11 , 16

Limnobia mitis Meigen 1830: 278 (description).

Limonia (Dicranomyia) mitis: Edwards 1938: 35 (short redescription), Text-fig. 5b (male terminalia). Limnobia mitis: Morge 1976 , Plate 78, Fig. 13 (general view).

Dicranomyia mitis: Stubbs 1998a: 22 (key), Figs (femora, macrotrichia on Sc 1, male terminalia).

Diagnosis. Medium-sized species. Body colouration greyish-brown, variegated with yellow. Wing pattern mostly fairly distinct, consisting of two spots at anterior wing margin, with additional markings especially along so-called outer cord. Sc1 with row of macrotrichia posteroventrally. Two last male tarsomeres long, parallel-sided; male tarsal claws moderately long, with two teeth fairly distinct. Male terminalia with rostral prolongation of ventral gonostylus truncate close beyond medial spine; rostral spines gently curved, separated at base by their own breadth. Female terminalia with cercus slightly shorter than tergite 10; space between cerci wide, subequal in width to cercus breadth at base. Wing length 6.2–9.4 mm.

Redescription. Male. Head with grey pruinosity on frons and vertex, rostrum yellowish-brown. Antenna dark brown, reaching to about anterior margin of prescutum. Flagellomeres short-ovoid, gradually narrowed towards apex of antenna, with verticils shorter than to subequal in length to respective segments. Palpus dark brown.

Thorax generally greyish-brown, restrictedly yellowed. Pronotum brown, yellowed laterally. Prescutum brown, with heavy grey pruinosity; scutal lobes, scutellum, and mediotergite variously yellowed laterally. Pleuron mostly brown, yellowed on dorsopleural membrane, with pale grey pruinosity. Wing pattern of varying intensity, often distinct, consisting of two spots at anterior margin, one, smaller, over origin of Rs and another, much larger and quadrangular, over distal part of R1 (pterostigma), and additional markings over apex of Rs (sometimes confluent with pterostigma) and along so-called outer cord; another seam along distal margin of discal cell (Fig. 16). Sc1 with row of macrotrichia posteroventrally. Halter with knob infuscated. Legs with coxae and trochanters yellow. Femora yellow with brown subapical ring, sometimes darkening extending to apex, resulting in long ring. Tibiae and tarsi darker. Two last tarsomeres long, subequal in length, straight, parallel-sided, rod-like; tarsomere 4 with longitudinal row of stiff, short, suberect setae ventrally; setae indistinctly hooked at tip. Tarsal claws moderately long, slightly less than one third length of tarsomere 5, with well-developed tooth proximal to midlength, this tooth rather pointed, and another one still fairly distinct. Other teeth little-distinct ( Fig. 1 ).

Abdomen dark brown dorsally, paler ventrally. Male terminalia ( Fig. 6 ): Tergite 9 rather long, about twice as broad as long, with shallow, often V-shaped, median emargination at posterior margin and mostly complete median suture. Gonocoxite moderately long, about half length of ventral gonostylus. The latter long-ovoid, about twice as long as broad. Rostral prolongation of ventral gonostylus truncate close beyond medial spine. Rostral spines gently curved, separated at base by their own breadth, or somewhat less so.

Female. Resembling male in general appearance, including structure of tarsi and tarsal claws. Female terminalia ( Fig. 11 ): Cercus gently upturned, slightly shorter than tergite 10. Space between cerci wide, subequal in width to cercus breadth at base, but shorter than that of D. (D.) affinis . Genital fork (vaginal apodeme) triangular, extending to posterior margin of tergite 10. Sternum 9 moderately long, about one third length of tergite 10.

Material examined (58 ♂, 23 ♀). Austria: Niederösterreich: Gutenstein env., 17. v.1994, 1 ♂ (J. Starý leg., JSO). Bulgaria: Sofia, Vitosha Mt., 8. v.1981, 1 ♂; Ostar Kamak, 3. v.1980, 3 ♂, 2 ♀, 5. v.1980, 1 ♀, 6. v.1980, 4 ♂, 1 ♀ (all W. Krzemiński leg., all JSO). Czech Republic: Bohemia: Bílina, Vršíček, 24. v.1996, 1 ♀ (M. Barták leg.); Šumava Mts, Pěkná, Vltava shores (750 m), 4. vi.2004, 2 ♂; Zvíčina [hill] nr. Dvůr Králové, 24. v.1972, 1 ♂ (all J. Starý leg., all JSO). Moravia: Hrubý Jeseník Mts (= Jeseníky Mts), Rejvíz (700 m), 2. vi.1971, 1 ♂, 17. v.2000, 4 ♂; Hrubý Jeseník Mts, Kouty nad Desnou, Divoká Desná valley, “Zámčisko” (970 m), 14. vi.2004, 1 ♂; Hrubý Jeseník Mts, Vidly, “Jelení bučina” (900 m), 16. vi.1998, 1 ♂; Hrubý Jeseník Mts, Petrovy kameny, peat-bog (1330 m), 2. vi.1998, 2 ♂; Hrubý Jeseník Mts, Karlova Studánka (900 m), 2. vi.1998, 1 ♂, 1 ♀, 13. v.1999, 1 ♂; Domašov nad Bystřicí, 29. v.1969, 1 ♂; Libavá env., Nové Oldřůvky, Odra valley, 2. vi.1993, 1 ♂; Hrubá Voda nr. Olomouc, 15. v.1969, 2 ♂; Hlubočky nr. Olomouc, 6. v.1967, 1 ♀; Střeň nr. Olomouc, 17. v.1967, 1 ♂; Slatinice, Kosíř, 14. v.1967, 1 ♂; Bukovec nr. Jablunkov, 25. vi.1997, 1 ♀; Moravskoslezské Beskydy Mts (= Beskydy Mts), Pustevny (1000 m), 26. vi.1985, 2 ♂, 2 ♀; Moravskoslezské Beskydy Mts, “Malinová“ (700–800 m), 15. vi.1989, 1 ♀, 27. vi.1991, 1 ♀; Moravskoslezské Beskydy Mts, Prostřední Bečva (500–600 m), 13. v.1992, 1 ♂, 3. v.1994, 2 ♂, 1 ♀, 10. v.1994, 4 ♂, 1 ♀; Moravskoslezské Beskydy Mts, Košařiska, 7.–8. vi.1995, 1 ♂ (at light); Moravskoslezské Beskydy Mts, Ostrý (500–1000 m), 7. vi.1995, 1 ♂; Moravskoslezské Beskydy Mts, Šance, “Vřesová stráň”, 25. vi.1997, 1 ♂; Lešná nr. Zlín (= nr. Gottwaldov), 23. v.1967, 1 ♂; Hostýnské vrchy [hills], “Bernardka” (500 m), 12. vi.1992, 2 ♂; Nejdek nr. Lednice, 22. v.2002, 1 ♂ (at light) (all J. Starý leg., all JSO). Great Britain: England: Hertfordshire, Letchworth, v.1918, 1 ♂, 1 ♀; Hertfordshire, Radwell, v.1918, 1 ♀; Hertfordshire, Felden, 10. v.1897, 1 ♀ (all F.W. Edwards leg.); Herefordshire, Pentelow (Glen) (part of Haugh Wood), 16. v.1878, 1 ♂ (J.H. Wood leg.); Hampshire, Frant, 16. vi.1886, 1 ♂ (G.H. Verrall leg.); Middlesex, Harrow, 6. v.1915, 1 ♀ (F.W. Edwards leg.) (all BMNH). Scotland: Nethy Bridge, 1. vii.1906, 1 ♀; Aviemore, 26. vi.1903, 1 ♀ (all J.J.F.X. King leg, all BMNH). Slovakia: Malá Fatra Mts, Biela (700 m), 28. v.1992, 2 ♂; Zuberec, Pálenica Mt., 25.vi.,1998, 1 ♂; Belianske Tatry Mts, Tristárska valley, 26. v.1976, 2 ♂, 1 ♀; Poľana Mts, Kyslinky, “Majerová” (850 m), 18. vi.2003, 2 ♂, 1 ♀; Poľana Mts, Čierny Potok (700 m), 25. v.2005, 1 ♂ (at light); Slovenský kras, Zádiel, plain, 22. v.1978, 1 ♂; Ruský Potok, 14. vi.1991, 1 ♀; Nová Sedlica, “Stužica”, 16. vi.1991, 1 ♂ (all J. Starý leg., all JSO).

Discussion. The two species, D. (D.) miti s and D. (D.) affinis , are distinctive in having a row of setae on Sc1 posteroventrally, whereas the other three species ( D. (D.) quadra , D. (D.) lutea , and D. (D.) imbecilla ) have Sc1 smooth, devoid of setae. Even if the setae are rubbed off in dry-mounted material their sockets are always fairly distinct under higher magnification. At the first sight D. (D.) mitis and D. (D.) affinis are different in general body colouration. This is greyish-brown in D. (D.) mitis , with predominant brown hue, but much darker, rather dark brownish to bluish-grey in D. (D.) affinis , with the ground colour black. Slight differences may also be seen in the structure of the male tarsomeres 4 and 5 and the male tarsal claws. In D. (D.) mitis , only tarsomere 4 bears stiff, short, suberect setae ventrally and the first tooth of the claw is rather pointed, whereas, in D. (D.) affinis , both tarsomeres 4 and 5 have the stiff setae and the first tooth of the claw is somewhat truncate (cf. Figs 1 and 2 ). The male terminalia of D. (D.) mitis have the rostral prolongation of the ventral gonostylus truncate close beyond the medial spine and the rostral spines separated at base by their own breadth. In contrast, in D. (D.) affinis , as the single species within the cluster, the rostral prolongation is slightly produced beyond the medial spine, and the rostral spines are separated at base by less than their own breadth (cf. Figs 6 and 7 ). The female terminalia of D. (D.) mitis have the cerci slightly shorter than tergite 10, and sternum 9 is about one third the length of tergite 10, whereas, in D. (D.) affinis , the cerci are subequal in length to tergite 10 and sternum 9 is more than half the length of tergite 10 (cf. Figs 11 and 12 ).

Ecology. In Great Britain, the species is widespread in the southern half of England, mainly on well-drained clay or limestone soils. It is absent on acid soils, can be present under mesotrophic conditions, but shows greatest affinity to mild or strong calcareous situations, preferring scrub edges associated with calcareous grassland. It is found more patchily to the north and west. The species can occur within woodland, but rarely in numbers. It is a member of the vernal fauna (May–early June), but, on an exceptional occasion, it was found in the autumn (October) ( AS). In the Czech Republic and Slovakia, this is the commonest and most widespread species occurring from high altitudes to lowland (JS).

Distribution. The species has been recorded from the whole of Europe, including adjacent territories as far south as Morocco and Algeria and as far east as Turkmenistan ( Oosterbroek 2014). Although confirmed here for Austria, Bulgaria, Czech Republic, Great Britain, and Slovakia only ( Germany should also be included as a country of a probable type locality of mitis , see Meigen 1830), occurrence of the species throughout Europe is to be expected.

Figures

FIGURES 1 – 5. T wo distal tarsomeres and tarsal claw (with details of tarsal claw). 1 — D. (D.) mitis (Czech Republic: Bohemia: Šumava Mts). 2 — D. (D.) affinis (Morocco: Rif Mts). 3 — D. (D.) quadra (Czech Republic: Moravia: Hrubý Jeseník Mts). 4 — D. (D.) lutea (Czech Republic: Moravia: Moravskoslezské Beskydy Mts). 5 — D. (D.) imbecilla (Czech Republic: Moravia: Hrubý Jeseník Mts). Scale bar 0.25 mm.

FIGURES 6 – 10. Male terminalia, general view, dorsal (with details of rostral prologation of ventral gonostylus). 6 — D. (D.) mitis (Czech Republic: Bohemia: Šumava Mts). 7 — D. (D.) affinis (Morocco: Rif Mts). 8 — D. (D.) quadra (Czech Republic: Moravia: Hrubý Jeseník Mts). 9 — D. (D.) lutea (Czech Republic: Moravia: Moravskoslezské Beskydy Mts). 10 — D. (D.) imbecilla (Czech Republic: Moravia: Hrubý Jeseník Mts). Scale bar 0.5 mm.

FIGURES 11 – 15. Female terminalia, internal structures, ventral. 11 — D. (D.) mitis (Czech Republic: Moravia: Moravskoslezské Beskydy Mts). 12 — D. (D.) affinis (Morocco: Rif Mts). 13 — D. (D.) quadra (Czech Republic: Moravia: Hrubý Jeseník Mts). 14 — D. (D.) lutea (Czech Republic: Moravia: Moravskoslezské Beskydy Mts). 15 — D. (D.) imbecilla (Czech Republic: Moravia: Hrubý Jeseník Mts). Scale bar 0.5 mm. ce—cerci; gf—genital fork (vaginal apodeme); ifp—infraanal plate; s 9 — sternum 9; t 10 — tergite 10.