This work is licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/us/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. THE PREDACEOUS WATER BEETLES (COLEOPTERA: DYTISCIDAE) OF ALBERTA: SYSTEMATICS, NATURAL HISTORY AND DISTRIBUTION DA VID J. LARSON Department of Biology University of Calgary Quaestiones Entomologicae Calgary, Alberta 11: 245 - 498 1975 One hundred and forty five species belonging to 17 genera of the family Dytiscidae are recorded from Alberta. Adults of each species are described and keys for identification are presented. Six species are described as new: Hydroporus criniticoxis, Hydroporus carri, Hydroporus hockingi, Hydroporus rubyi, Agabus margareti and Acilius athabascae. The species Hygrotus picatus (Kirby) is recognized as valid, and the name Dytiscus alaskanus J. Balfour- Browne is revalidated. The following new synonymy is proposed: Hydroporus coloradensis Fall = H. griseostriatus (DeGeer); Hydroporus hortense Hatch = H. laevis Kirby; Hydroporus productotruncatus Hatch = H. alaskanus Fall; Rhantus aequalis Hatch = R. binotatus (Harris); Dytiscus ooligbukii Kirby = D. circumcinctus Ahrens; and Dytiscus vexatus Sharp = D. dauricus Gebler. For each species, the following information is presented: synonymy, selected literature ref­ erences, description, taxonomic notes, natural history notes, and distribution, which includes a brief outline of the species range and a map showing Alberta collection localities. Illustrations of taxonomically important characters are presented. The post-glacial distribution of the Alberta species is discussed and related to post-glacial vegetational movements and climatic change. The sources of most elements of the Alberta dytiscid fauna cannot be determined definitely but it is shown that the fauna is of diverse origin. A Prairie, Boreal and Cordilleran fauna comprise the Alberta fauna. Each component is of complex origin and is defined on the basis of similarities in range ends of its constituent species rather than actual associations of species forming discrete faunal units. The areas of the province with richest faunas are those of a transitional nature. Les coleopteres dytiscides en Alberta comprennent cent-quarante-cinq espec?s distributes en 17 genres. Chaque espece est decrite et nous presentons une clef pour leur identification. Nous avons decrit six especes nouvelles: Hydroporus criniticoxis, Hydroporus carri, Hydroporus hockingi, Hydroporus rubyi, Agabus margareti et Acilius athabascae. L'espece Hygrotus picatus (Kirby) est valide, et le nom Dytiscus alaskanus/. Balfour-Brown est de nouveau valide. Nous avons propose la nouvelle synonymie suivante: Hydroporus coloradensis Fall = H. griseostriatus (DeGeer); Hydroporus hortense Hatch = H. laevis Kirby; Hydroporus productopunctatus Hatch = H. alaskanus Fall; Rhantus aequalis Hatch = R. binotatus (Harris); Dytiscus ooligbukii Kirby = D. circumcinctus Ahrens; et Dytiscus vexatus Sharp = D. dauricus Gebler. Nous avons Vinformation suivante pour chaque espece: la synonymie, les references choisies, la description, les notes taxonomiques, les notes sur I'histoire naturelle et la distribution qui indue en court sommaire de la distribution de l'espece et une carte montrant les localitees de collection en Alberta. Nous avons illustre les caracteres taxonomiques importants. Nous avons discute la distribution post-glaciere des espece albertaines en relation aux mouve- ments post-glaciere de la vegetation et du changement climatique. L 'origine de la plupart des dytiscides albertains ne peut pas etre determinee definitivement, mats nous avons demontre leur origine diverse. La faune se compose d'elements des prairies, des regions boreales et des rocheuses. Chaque groupe est d'origine complexe et nous les avons definis en fonction de similarites dans la terminaison de la distribution de leurs especes constituantes plutot que par * Present address: Saskatchewan Fisheries Laboratory, 30 Campus Drive, Saskatoon, Sask. S7N 0X1. 246 Larson Vactuelle association des especes formants des unites faunales discretes. Les regions de la province les plus riches se rencontrent dans les regions de transition. TABLE OF CONTENTS Introduction 246 Study Area 246 A Brief History of Systematic Study of North American Dytiscidae 247 Material 248 r Methods 249 Systematics 254 Key to Adults of Genera of Alberta Dytiscidae 257 Subfamily Laccophilinae 258 Subfamily Hydroporinae 261 Subfamily Colymbetinae 327 Subfamily Dytiscinae 394 INTRODUCTION This survey of the dytiscid beetle fauna of the province of Alberta deals with systematics, distribution and very briefly, habitat preferences of the species. In spite of statements in the literature such as Arnett's (1963) that "As a group, the species (of the family Dytiscidae) are well known", many taxonomic problems require study. The higher taxa in the family are well defined, but within the larger genera such as Hydroporus and Agabus, the arrangement of species in supraspecific categories is unsettled. Many genera and species groups require revision. Certain species are well known and well defined. However, many instances of inter- and intrapopulation variation, sexual di- or polymorphisms, and occurrence of groups of morphologically very similar species, have been observed. I point out such areas of taxonomic complexity. The Alberta distribution of each species is described as fully as possible. Certain areas of the province have been collected extensively. However, large and zoogeographically important areas such as much of the northern portion of the province, the parkland belt of east-central Alberta, and the northern Rocky Mountains in and adjacent to Jasper National Park, have been collected only superficially. Extensive collecting in these areas may lead to the discovery of new provincial records, and will at least modify certain of the distribution patterns outlined in this study. Attempts have been made to explain the post-glacial distribution of the present fauna by consideration of present-day distribution patterns. Natural history data consist of brief descriptions of the habitat in which adult specimens of each species are most frequently found. The time of year at which teneral adults are found is listed for each species, as this gives some idea of the seasonal timing of the life history. Im­ mature stages have not been considered in this study. Much work remains to be done in terms of relating larvae to adults, description of life histories, and detailed ecological studies of species. In addition to their inherent biological interest, studies of these insects could appraise their role as predators on economically important insects such as mosquitos, and as indicators of environmental conditions. THE STUDY AREA The limits of the study area are the political boundaries of Alberta. This large area includes Dy tiscidae of Alberta 247 a varied range of geological, climatic and vegetational zones. Physical and biotic features of the province are described in Hardy (1967) and R. D. Bird (1961), Moss (1947, 1953, 1955) and Rowe (1959) describe major vegetational features. Probably, no species of dytiscid beetle is restricted to Alberta. Most species occurring in Alberta range extensively in central, western or northern Canada. By including all species known from neighbouring Canadian areas in at least the keys, it is hoped that this work will be useful for identification of dytiscids of southeastern British Columbia, the Prairie Provinces and the southern reaches of the Northwest Territories. A BRIEF HISTORY OF SYSTEMATIC STUDY OF NORTH AMERICAN DYTISCIDAE The early history of taxonomic work on the North American dytiscid fauna closely parallels that on the North American carabid fauna as outlined by Lindroth (1969). Many temperate and arctic species of Dytiscidae are Holarctic and hence a number were described by early European workers. North American populations of many of these Holarctic species were de­ scribed as separate species and even to this date, the relationships between certain morpholog­ ically similar forms in the Palaearctic and Nearctic regions have not been determined. W. Kirby (1837) and C. Aube (1838) were the first Europeans to describe large numbers of North American species. Kirby's types of North American Dytiscidae, housed in the British Museum of Natural History, London, were examined in the course of this study. Most of Aube's types, located in the Royal Museum of Natural Sciences, Brussels, Belgium, were not revised by North American workers. T. Say, in papers between 1823 and 1834, was the first North American to describe many water beetles. Say's types are considered to be lost, but recent authors have generally accepted interpretations as indicated by specimens in the LeConte collection in the Museum of Comparative Zoology, Harvard University. T. W. Harris (1828, 1829) described several species of Dytiscidae from the eastern United States. Harris' types are also located in the Museum of Comparative Zoology. During the mid 1800's, J. L. LeConte, in a series of papers (1845 - 1878), described a very large number of dytiscid beetle species,presented catalogue listings, and revised several of the larger genera. G. R. Crotch (1873) revised the North American members of the family and described a number of new species, but the descriptions are generally too brief to allow reliable