Tanysphyrus ater Blatchley, 1928 (Erirhinidae) new to the British Isles

摘要

On 26 June 2011, while looking for beetles at the edge of a small pond on Thompson Common, West Norfolk (VC 28; TL9396), I took a specimen of what I assumed to be the duckweed weevil Tanysphyrus lemnae (Paykull), and it was added to my collection as that species. More than two years later, in November 2013, I had reason to re-examine my short series of lemnae and it soon became apparent that the Thompson Common specimen was distinctly different from the rest (Fig. 1), having black rather than red tibiae, completely black antennae rather than the antennal bases reddish, copious white scales on the pronotal sides, and absence of the subapical internal tibial tooth which is a character of lemnae. Reference to Lohse (1983) and habitus photographs in Rheinheimer & Hassler (2010) pointed me towards T. ater Blatchley (= makolskii Smreczynski), a species not previously recorded in the British Isles. This identification was reinforced by noting other more comparative characters, namely the slightly straighter rostrum and comparatively small pronotum of ater.