Delia coarctoides Michelsen

Michelsen, Verner, 2007, A new European species of Delia Robineau­Desvoidy (Diptera: Anthomyiidae) near the wheat bulb fly, D. coarctata (Fallén), Zootaxa 1412, pp. 61-67 : 63-64

Delia coarctoides Michelsen , sp. nov.

Figs. 1 , 3 , 5 , 7–11 .

Etymology. The specific epithet ‘coarctoides’ is derived from ‘coarctata’, existing name for the most similar species, and ‘­oides’, a Greek adjectival suffix meaning ‘resembling’.

Material examined. Type material. Holotype male, DENMARK: Jutland (W): Årgab, reared 16.ix.1951 from puparium found 30.vii.1951 (K.O. Leth), ZMUC. Paratypes. DENMARK: Jutland (W): 5 males, 5 females with same data as for the holotype, ZMUC.

Additional material (in ZMUC if not stated otherwise). CZECH RUPUBLIC: Bilina­Vršiček, mixed wood, 420m, Malaise­trap, 1 male 25.vi–23.vii.1998 (Barták). DENMARK: W Jutland: Årgab, 29 males, 21 females, reared 16.ix.1951 from puparia found 30.vii.1951 (K.O. Leth); Skallingen, 1 male 10.vii.1932, 1 female 25.vii.1932 (E. Bro Larsen). NE Jutland: Hulsig, 1 male 11.vii.1908 (Mortensen); Skagen, Grenen, 1 male 17.vii.1985 (H. Enghoff). FINLAND: Nylandia: Tvärminne, 2 males 12.viii.1923 (F. Frey), FMNH. Karelia australis: Vehkalahti, 1 male 3.viii.1974 (Tiensuu), FMNH. Tavastia australis: Topeno, Loppi, 1 male 8.vii.2005 (I. Kakko). Karelia borealis: Joensuu, 2 males 9­13.vii.1976, 1 male 9.viii.1982 (O. Martin). SWE­ DEN: Skåne: Löderup, 1 male, 1 female 11.vii.1923 (O. Ringdahl); Hagestad, 1 male 11.viii.1983 (H. Andersson), MZLU.

Description. The general descriptions of D. coarctata given by Hennig (1974a) and Griffiths (1991, 1992) also apply to the new species D. coarctoides with a few exceptions as emphasized in the following. It is reliably separated from D. coarctata in the male sex only, although a differential description of both sexes is attempted in the following:

Male. Vein C on basal section, between humeral and subcostal breaks, with several v setulae vs. bare on ventral surface. Fore tibia with apical pv seta short, pointed at tip ( Fig. 1 ) vs. long and coarse, truncated at tip ( Fig. 2 ). Length of fore tarsomere 1 equals length of fore tarsomeres 2–4 combined ( Fig. 1 ) vs. fore tarsomere 1 nearly as long as tarsomeres 2–5 combined ( Fig. 2 ). Mid tibia with 2 pd and 2 pv setae normally developed vs. same setae strikingly short and weak. Cercal plate in caudal view short, cordiform, less than 1.5 x longer than wide ( Fig. 3 ) vs. elongated, in caudal view c. 2.0 x longer than wide ( Fig. 4 ). Surstylus in lateral view markedly expanded on subdistal part ( Fig. 5 ) vs. barely expanded subdistally ( Fig. 6 ). Phallus, gonites and hypandrium ( Fig. 7 ) and sternite V ( Fig. 8 ) as in D. coarctata .

Female. Prealar seta short but distinct vs. absent or indiscernible from surrounding ground setulae. Vein C on basal section, between humeral and subcostal breaks, with several v setulae vs. bare on ventral surface. Spermathecae and ducts ( Fig. 9 ) and distal sclerites of oviscapt ( Figs. 10–11 ) as in D. coarctata .

Taxonomic remarks. I have earlier ( Michelsen 1983, 1985) examined the primary types of Musca coarctata Fallén , Anthomyza leptogaster Zetterstedt and Aricia paralleliventris Zetterstedt and can confirm that they all belong to Delia coarctata (Fallén) . Hennig (1974a) further examined the female holotype of Hylemyia garbiglietti Rondani from Piemonte, Italy and synonymized it with D. coarctata . I cannot see any reason to question Hennig’s identification.

Distribution and biology. Known so far only from a few localities in southern Fennoscandia and a single record from the Czech Republic. The known collecting sites in Denmark and Sweden all have sandy coasts with white dunes or similar sandy, sparsely vegetated areas dominated by marram ( Ammophila arenaria ) and lyme­grass ( Leymus arenarius ). A likely possibility is therefore that either of these coarse grasses is favoured as a host plant for the larva of D. coarctoides .

Figures

FIGURES 1 – 2. Male right distal fore tibia and tarsus. 1. Delia coarctoides sp. nov. with numbered tarsomeres. 2. D. coarctata (Fallén). Arrows point at apical pv seta. Same scale.

FIGURES 3 – 4. Hypopygium, caudal. 3. Delia coarctoides sp. nov. 4. D. coarctata (Fallén). Notice shape of cercal plate. Same scale.

FIGURES 5 – 6. Hypopygium, lateral. 5. Delia coarctoides sp. nov. 6. D. coarctata (Fallén). Notice shape of cercal plate and subdistal surstylus. Same scale.

FIGURES 7 – 11. Delia coarctoides sp. nov. 7. Male hypopygial parts in left lateral view. 8. Male sternite V. 9. Female spermathecae and ducts. 10. Female cerci, epiproct and tergite VIII. 11. Female hypoproct and sternite VIII. Same scale for 7 – 8 and 10 – 11 respectively.