HANSEN, M. (1997): Phylogeny and classification of the staphyliniform beetle families (Coleoptera)

In less than a decade, M. Hansen published several major interrelated books on beetles. The first of these, in 1991, was a detailed morphological and phylogenetic account of the Hydrophiloidea, Hansen’s main study group (see AQUATIC INSECTS 15: 108). Arrangement and ranking of the hydrophiloid taxa in the 1991 publication already relied on some results published in more detail in the 1997 work. The present book is, however, much more comprehensive and analyses the monophyly and intrinsic relationships of the Staphyliniformia, a very large group comprising about 60000 named species. Members of all included families and subfamilies and of many tribes plus several outgroup taxa were examined. The methods of preparation and study of specimens as well as of analysis are those applied also in 1991, i.e., a computer-supported study using parsimony. 68 plates with numerous excellent drawings of structural details and beetle habitus (the latter mostly after V. Hansen) support the character descriptions and character state evaluations; several cladograms accompany the phylogenetic analysis and the discussion in support of the preferred cladogram. The results differ from those of Lawrence & Newton (1995) mainly in that Hansen includes the Scarabaeoidea (dung beetles, chafers, stag beetles and relatives) in this assemblage and in that Hansen divides the Staphyliniformia into three superfamilies, Hydrophiloidea, Histeroidea, and Staphylinoidea (nominate family: the rove beetles), while Lawrence and Newton regarded the Histeridae as a subgroup of the Hydrophiloidea; because most stapyliniform families are terrestrial, details are not needed here. Most aquatic Staphyliniformia were historically grouped together, often as a single family, Hydrophilidae, of which the combination of short (and often modified) antennae with elongate maxillary palpi was diagnostic. Modern analyses have shown this to be a superficial misleading resemblance, the Hydrophiloidea in a modern restricted sense (see Hansen, 1991) are not closely related with the Hydraenidae which actually belong to the Staphylinoidea. Zoological catalogues are an invaluable tool for all systematic studies, from comprehensive synoptic works like the ones discussed above to alpha-taxonomy. A world catalogue of the Hydraenidae by M. Hansen (1998) was the first volume of a World Catalogue of Insects, and now follows already the second volume, by the same author, this time a voluminous catalogue of the Hydrophiloidea. All that I said about the significance and value of this project by Apollo Books (AQUATIC INSECTS 22: 18) applies to the present work, and general structure and format of entries are also as in the first volume. It therefore suffices to underline the need for this publication and to highlight its importance in the study of aquatic insects by comparing species numbers between the present book and its immediate predecessors: there are now about 2800 species of Hydrophiloidea, more than twice as many as in the catalogues by Knisch (1924) and Zaitzev (1910, for the Georissidae)! The present catalogue volume lists 58 pages of references (almost all of which the author has seen) and the index to taxa names covers 30 pages; these figures alone provide one with a good estimate of the amount of work done and of the importance of the help provided to colleagues in the same field of study!