Allodia (Brachycampta) alternans ( Zetterstedt, 1838 )

Kjaerandsen, Jostein, 2005, A review of fungus gnats in the tribe Exechiini (Diptera, Mycetophilidae) from the J. W. Zetterstedt collection at the Museum of Zoology in Lund, Sweden, Zootaxa 856, pp. 1-35 : 15

Allodia (Brachycampta) alternans ( Zetterstedt, 1838)

Mycetophila alternans Zetterstedt, 1838: 866

Brachycampta alternans ; Lundström 1909: 24, figs 26 & 27

nec Brachycampta alternans ; Coquillett 1910: 515

nec Brachycampta alternans ; Dziedzicki 1915: 11, figs 129 & 130

Allodia alternans ; Edwards 1921: 123, fig. 9

nec Mycetophila alternans ; Edwards 1924: 163

Allodia alternans ; Edwards 1925: 608

? Allodia delicata Ostroverkhova, 1977: 78 , fig. 5

Material. Holotype, sex unknown, lacking abdomen, on the same pin as a male Exe­

chia spinuligera Lundström, 1912 [SPM­005153, mounted on slide, without coloured

tag, labelled: M. alternans Zett ď. ( M. fusca Ψ) Karungi] – Sweden: NB, Karungi, 28.

August 1821. Neotype ( Fig. 3 ). Male [SPM­005726, mounted on slide, MZLU] –

Sweden: LU, Jokkmokk, Kaltisjokk at Messaure, barber traps 101–120, 0 2. September

­ 0 4. October 1971, leg. K. Müller.

The first specimen above is the type of Mycetophila alternans Zetterstedt, 1838 as can be decided by its co­occurrence with an Exechia spinuligera Lundström 1912 on the same pin as well as the label giving the name and type locality "Karungi". Both these facts are mentioned in the description given in Zetterstedt (1838: 866). Unfortunately the abdomen of the type specimen is lost and without reference to the genitalia the true identity of the type cannot be established beyond subgenus level. Allodia (Brachycampta) alternans apparently has been mixed with A. (B.) grata (Meigen, 1830) by several authors (e.g. Coquillett 1910; Dziedzicki 1915). Edwards (1921) illustrated A. (B.) alternans in accordance with Lundström's (1909) interpretation, and this has later become the prevailing usage of the name by subsequent authors (e.g. Edwards 1925, Zaitzev 1984, 2003). Nevertheless, as Edwards (1924) did not examine the "Insecta Lapponica" collection he reported the type as missing and referred to a male labelled "Bjorn" as being in co­ordinance with his interpretation of Allodia alternans . The specimen labelled "Björn", however, belongs to Allodia (Brachycampta) grata (Meigen, 1830) [see below] as figured by Dziedzicki (1915) under the name A. (B.) alternans . It remains an open question whether Zetterstedt's type in fact is the same as Lundström's interpretation of A. (B.) alternans . Apart from the type no other specimens of A. (B.) alternans as treated by Lundström (1909) and others were found in the Zetterstedt collections. On the contrary, the second male determined as Mycetophila alternans Zetterstedt, 1838 in Zetterstedt (1852: 4215) is in fact referable to Allodia (Brachycampta) grata . To avoid further speculation and preserve nomenclatural stability it thus seems appropriate to select and illustrate a neotype for A. (B.) alternans in accordance with Lundström's drawing ( Lundström 1909: plate III, figs 26–27) and prevailing usage of the name.

Figures

FIGURE 3. Male neotype of Allodia (Brachycampta) alternans (Zetterstedt, 1838) – A. Terminalia in ventral view. – B. Tergite IX and cerci in dorsal view. – C. Internal face of right gonostylus. Bar = 0.2 mm.