Hydrophiloidea Latreille, 1802

Abstract

Since the first of three Coleoptera volumes of the Hand-book of Zoology series was published in 2005, the progress in the investigation of the most species-rich insect order has been remarkable. The exploration of the biodiversity of this extremely successful group of organisms has been dynamic, with valuable contributions made by individual naturalists, but also by organized research teams conducting large-scale biodiversity expeditions in different parts of the world. These efforts have yielded a remarkable increase in species numbers in different groups, as for instance in Hydrophiloidea from ca. 2,800 in 2005 (1stedition) to 3,335 in 2015 (1?12), or in Staphylinidae from 47,744 in 2005 to 55,224 in 2015 (1?14.7), the later of which is also related to advances in classification. Moreover, a considerable number of new genera were described as well as two new families of Adephaga, which were not included in the 1stedition of Volume 1 (included in Volume 2 of 2010). The biodiversity explorations were accompanied by intensive taxonomic work conducted not only by professional researchers but also highly competent amateurs. Even though taxonomic research may not be greatly appreciated in parts of the scientific community, or governments, it is essential for the understanding of a highly complex and immensely diverse group like Coleoptera and generally for the development of stable classifications. An updated classification for the all Coleoptera is presented in Chapters 1?2. Important changes adopted here are the placement of Scirtoidea at the base of Polyphaga, and a new concept of Hydrophiloidea with subfamilies ranked as families (Chapters 1?12).With remarkable technical innovations in insect anatomy in the last decade, the study of the morphology of Coleoptera has also intensified. Recently, as part of the Beetle Tree of Life project (funded by the United States National Science Foundation), an impressive morphological contribution was made by John Lawrence, Adam Ślipiński (CSIRO), and coworkers. This team of experts compiled, documented, and analyzed a comprehensive set of 516 characters representing 314 families and subfamilies of Coleoptera plus outgroups. New and detailed morphological data are available for species of many groups (e.g. cephalic and thoracic morphology of Archostemata, head morphology of Lepiceridae, Dascillidae, and Glaresidae, genital morphology of Ommatidae, Chapters 1?5.4), and larvae of several groups were described for the 1sttime (Lepiceridae, 1?6.1, Meruidae, 1?7.8) or treated in detail morphologically, including complete 3D.reconstructions of external and internal structures (e.g. 1stinstar larvae of TenomergaNeboiss [Cupedidae], 1?5.2). The remarkable development of molecular systematics in the last decade had also a strong impact on beetle phylogenetics and evolutionary biology. A completely new chapter on molecular systematics is presented in this volume (1?3). One major achievement was the unambiguous systematic placement of Coleoptera as sistergroup to the highly specialized ectoparasitic Strepsiptera, both combined as Coleopterida, which in turn form the sistergroup to a clade containing the three neuropteroid orders. Another breakthrough was the identification of the scirtoid families and Derodontidae as basal lineages of the megadiverse Polyphaga.The composition of the authors for this revised Volume 1 has changed slightly. Chuck Bellamy, regrettably passed away prior to the formulation of this new edition, and Buprestidae (1?18) were revised with the assistance of Mark Volkovitsch (Institute of Zoology, Russian Academy of Sciences, St. Peterburg). Some authors were unavailable or were substituted by authors more recently active in the taxonomy of particular families. Duane McKenna (University of Memphis) is co-author of Systematic position and early evolution (1?1) and new author of Molecular systematics of Coleoptera; (1?3), Lars Hendrich (Zoologische Staatssammlung München) as new co-author of Dytiscidae (1?7.6), Pawel Jaloszynski (Museum of Natural History, University of Wrocław) and as new author of Scydmaeninae; (1?14.5), and Crystal Maier (Field Museum of Natural History, Chicago) as leading author of Byrrhidae (1?19.1).Not only are great strides being made to document beetle diversity and morphology, the investigation of beetle phylogeny is also presently progressing with great momentum. The phylogeny of the entire Coleoptera was addressed in the BTOL project and is presently investigated based on transcriptomes in a subproject of the 1KITE consortium (www.1KITE.org/, funded by Beijing Genomics Institute). This and other ongoing molecular investigations underway by teams of researchers combined with new morphological findings and an intensified exploration of rich fossil material, will likely lead to a deeper understanding of beetle evolution and new classifications in the near future. The updated information compiled in this volume may facilitate and inspire ongoing research efforts, and new phylogenetic and evolutionary insights may eventually lead to new contributions in the Handbook of Zoology series.