Ditaeniella parallela Walker, 1853

Vikhrev, Nikita E. & Murphy, William L., 2022, Notes on the taxonomy of species of Sciomyzini with a predominantly setulose anepisternum (Diptera, Sciomyzidae), Amurian Zoological Journal XIV (2), pp. 281-298 : 292-293

Ditaeniella parallela Walker, 1853

Figs. 9 , 16, 17, 18, 19

Sciomyza parallela Walker 1853

Sciomyza humilis Loew 1876

Sciomyza serena Wulp 1897

Melina (Ditaenia) grisescens Meigen, 1830 ( Cresson, 1920: 49–50)

Pherbellia parallela ( Johnson 1925: 250) Ditaeniella parallela ( Rozkošný 1987: 18) Ditaeniella parallela Walker, 1853 : redescription in Murphy et al. (2018: 56–58)

Material examined: see specimens listed in Murphy et al. (2018: 57–58) and Murphy (2020: 9).

New specimens examined: USA: Texas: Laguna Madre, 25 km SE Harlingen (26.0 ° N, 97.6 ° W), D. E. Hardy, 25.01.1945, 2♂ (with L. V. Knutson’s determination label “ Ph. humilis Loew ” and G.C. Steyskal’s determination label “ Ph. grisescens ”) ( ZIN); Brazos Co., College Station , 30.60 ° N, 96.35 ° W, 10.10.2015, V. Belov, 1♂ ( ZMUM) .

Distribution. Widespread in USA and Canada, also known from Mexico and Dominican Republic.

Remarks. Cresson (1920) and Sack (1939) regarded D. parallela as a synonym of D. grisescens on the basis of non-genitalic characters; we also found no non-genitalic differences. Steyskal (1963) examined the genitalia of D. grisescens and D. parallela and published drawings of them, having found them to differ ( Figs. 7, 9 ), but he failed to explain which differences in his drawings were diagnostically important. Males of D. parallela differ from those of D. grisescens by the structure of their genitalia: in D. parallela , the sclerotised portion of the cercus forms a flat paired plate, broadened and upcurved apically ( Figs. 9 , 19 ); and the postgonites each bear only a single strong spine ( Fig. 18 ). Females of D. parallela are undistinguishable from those of D. grisescens .

As will be shown in Part III, the distance between COI sequences among Palaearctic specimens of Ditaeniella grisescens is much greater than that among Nearctic specimens. This suggests an Old-World origin of Ditaeniella . If so, D. parallela must have colonised North America via the Bering Land Bridge, which existed 30,000 –11,000 years BPE.

Ditaeniella patagonensis Macquart, 1851

See: Ditaeniella grisescens : Notes on synonymy of Ditaeniella patagonensis .

Figures

Figs. 7–9. Postabdomen ofDitaeniella species in lateral view (modified from Steyskal 1963: figs. 8–10): 7 — D. grisescens; 8 — D. patagonensis; 9 — D. parallela Рис. 7–9. ПостабΔомен таксонов Ditaeniella, виΔ сбоку (по Steyskal 1963: figs. 8–10): 7 — D. grisescens; 8 — D. patagonensis; 9 — D. parallela

Figs. 16–19. Ditaeniella parallela, male: 16 — dorsal view; 17 — ventral view with arrow indicating ventral spines on f3; 18 — postabdomen, ventral view, postgonites are visible, each bearing only a single spine; 19 — postabdomen, lateral view with arrow pointing to apically curved sclerotised portion of cerci Рис. 16–19. Ditaeniella parallela, самец: 16 — виΔ сверху; 17 — виΔ снизу, стреΛка указывает на вентраΛьные шипики на f3; 18 — постабΔомен снизу, виΔны постгониты, кажΔый из которых несет по оΔному шипику; 19 — постабΔомен сбоку, стреΛка указывает на скΛеротизированные выросты на церках