Results of a Coleoptera collection from the Tristan da Cunha Islands (Tristan and Nightingale) made in 2005 are presented, revealing 16 new records: Eleven species from eight families are new records for Tristan Island, and five species from four families are new records for Nightingale Island.
Two families (Anthribidae, Corylophidae), five genera (Bisnius STEPHENS, Bledius LEACH, Homoe- odera WOLLASTON, Micrambe THOMSON, Sericoderus STEPHENS) and seven species Homoeodera pumilio WOLLASTON, 1877 (Anthribidae), Sericoderus sp. (Corylophidae), Micrambe gracilipes WOLLASTON, 1871 (Cryptophagidae), Cryptolestes ferrugineus (STEPHENS, 1831) (Laemophloeidae), Cartodere ? constricta (GYLLENHAL, 1827) (Latridiidae), Bisnius sordidus (GRAVENHORST, 1802) (Staphylinidae) and Bledius sp. (Staphylinidae), have not previously been recorded from the Tristan da Cunha Archipelago. Amongst the new findings from Tristan da Cunha Island is the flightless Liodessus involucer (BRINCK, 1948) (Dytiscidae), known as endemic to the other three main islands in the Tristan group. We discuss this intriguing new record and present an observed scenario involving the possible role of Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos GMELIN, 1789) in transferring the species from Nightingale.
A summary of all the coleopteran species known from the Tristan da Cunha Islands to date is provided with comparisons to those known previously, revealing an increase at Tristan Island of 133 % in 67 years being principally alien species, and for the still incompletely surveyed archipelago as a whole, an increase over 40 years of 42 %, being all alien species.