Career
He was Director of the Vienna Natural History Museum. Holdhaus worked on the Coleoptera of glacial refugia, postglacial range expansions and “Massifs de Refugium”. He recognised that the distribution of blind euedaphic and troglobitic beetles is restricted to a well definable area in Europe, south of a line connecting Bordeaux, Lyon, the southern Alps, the Carpathians and the Black Sea.
This is the “Holdhaus line” - the northern distribution limit of beetles with very poor powers of dispersal, especially blind cave beetles.
Only two small areas with blind beetles are known north of this line the Jura and the Northeastern Alps).Also South of this line there are many endemic animal and These areas are the “Massifs de Refugium” of Chodat & Pampanini (1902). Holdhaus" collection is Naturhistorisches Museum in Vienna.
