Beris nigra MEIGEN , 1820

Zeegers, Theo, 2021, Notes on the types of Beris LATREILLE, 1802 (Diptera, Stratiomyidae) in the Meigen collection, Linzer biologische Beiträge 53 (1), pp. 431-435 : 431-432

Beris nigra MEIGEN, 1820

Beris nigra was described by MEIGEN (1820) from a female, supposedly sent to him by Leach and illustrated in an unpublished plate (facsimile reproduction by MORGE (1976)). The holotype is still present at MNHN ( figs 1-2 ). It is in generally good condition, though the head and abdominal tip are missing.

This species was considered likely to be B. chalybata (FORSTER, 1771) by VERRALL (1909) ("appears to me to be"), a nomen dubium, but surprisingly close to B. strobli by ROZKOŠNÝ (1982) and synonymous with B. fuscipes MEIGEN, 1820 by WOODLEY (2001) (fig. 3). In the latter species, the female frons is much narrower than the width of an eye. However, in the holotype the vertex is wide (well supported by the original description and plate) and therefore, I agree with ROZKOŠNÝ (1982) the synonymy with B. fuscipes cannot be accepted. A broad vertex is found only in B. chalybata , B. hauseri and B. strobli . All metatarsi of the holotype are yellow, which is an unique character for B. hauseri ( MARTENS et al. 2013) . Moreover, the yellow femora and tibiae with broad dark bands on all femora and hind tibia also indicate B. hauseri . Hence, Beris nigra is a senior synonym of the species currently known as B. hauseri syn.nov. Clearly, Meigen’s name has priority.

It has been argued that B. nigra cannot be identical with B. strobli , or B. hauseri , since those species are not recorded from the United Kingdom, where the locus typicus is supposed to be. Given its presence in western Belgium ( MARTENS et al. 2013) and the Netherlands ( BRUGGE 2002, as B. strobli ), Beris nigra might occur or have occurred in the United Kingdom. A reexamination of the British material is necessary to evaluate the current status of B. hauseri in the United Kingdom. There is also a possibility of a mix-up at Meigen’s desk. Published type localities outside the known distribution can simply be in error, as for instance shown in the case of Rhagio mellinus BECKER, 1921 ( ZEEGERS & ÁLVAREZ FIDALGO 2018). If we do insist that B. nigra cannot be synonymous with B. hauseri because its type from the United Kingdom, we are left with a specimen belonging to a species found only once before 1820, never to be found again. This is unlikely, to say the least. Apart from the type locality, the synonymy is obvious and straightforward.

Due to the confusion between Beris nigra and B. strobli , most records for B. strobli mentioned in the older literature are unreliable, including ROZKOŠNÝ (1982). Beris strobli was described from the Austrian Alps and is recorded from Germany (Alps, Harz), Czech Republic (above 600 m.) and Hungary by STUKE (2004), Italy (Stelvio at altitudes between 930-2315 m.) by STUKE (2008) and from Switzerland (altitudes 1800-1920 m.) by HAENNI (2019). I have seen pictures of genuine B. strobli from Slovakia (Mala Fatra). Contrary, all specimens seen from lower altitudes, including of all Scandinavia, belong to B. nigra rather than B. strobli . This includes Belgium ( MARTENS et al. 2013), the Netherlands ( BRUGGE 2002), Germany ( STUKE 2004), Norway ( FALCK 2007), Sweden as far north as 62 oN (diptera.info) and Finland ( KAHANPÄÄ et al. 2014). It should definitely occur in Denmark. HAENNI (2019) records B. nigra (as B. hauseri ) from Switzerland, but only from the Jura up to 1200 m above sea level. The general picture is that B. strobli is restricted to the mountains of central Europe, whereas B. nigra occurs all over temporal and boreal Europe at lower altitudes, reaching 1200 m above sea level in the Jura.

Figures

Figs 1-2. Beris nigra MEIGEN, 1820, holotype. (1) Dorsal. (2) Lateral. [courtesy Museum national d’histoire naturel, Paris]