Holarctic distribution of Osmia (Melanosmia)
In a recent paper, Rightmyer, Griswold and Arduser (2010) review the non-metallic Osmia (Melanosmia) species of North America. Interestingly, Osmia laticeps Thomson, 1872 and Osmia maritima Friese, 1885, which were thought to be confined to the Palaearctic region, also occur in North America. Other Melanosmia species with a holarctic distribution are Osmia inermis (Zetterstedt, 1838) and Osmia nigriventris (Zetterstedt, 1838). The northern temperate to boreoalpine distribution of most non-metallic Melanosmia species may have facilitated the intercontinental exchange of some species via Beringia.