Damselfly genera of the New World. An Illustrated and Annotated Key to the Zygoptera

86. GARRISON, R.W., N. VON ELLENRIEDER & J. A. LOUTON

The John Hopkins University Press

Lugar: Baltimore; Año: 2010 p. 490

0-8018-9670-3

Dragonfly Genera of the New World: An Illustrated and Annotated Key to the Anisoptera was published in 2006. The present volume complements the first by treating the Zygoptera, or damselflies. Dragonflies and damselflies (Order Odonata) continue to be a very popular group of insects. Their relatively large size, striking coloration, interesting biology, and relative fewness in numbers of species (about 5,700 species) compared with other orders of insects are factors contributing to their popularity. Odonate larvae generally have high habitat fidelity, and can thus be used as indicators of the health of aquatic ecosystems. Adults are usually active only during daylight hours and may be collected by aerial netting. Despite their popularity, there has been no means of easily identifying species from the richest area of biodiversity, the Neotropical region, until recently. This area has about 1,730 species in 207 genera, or about 30% of the world’s total (von Ellenrieder, 2009). The closest area in number of species is the Oriental region with 1,705 species (Kalkman, Clausnitzer, Dijkstra, Orr, Paulson, and van Tol, 2008). Within the past ten years a comprehensive account of the Odonata from the United States and Canada has been published (Needham, Westfall, and May, 2000; Westfall and May, 2006), resulting in an increase in interest by students and the general public. In contrast, for Mexico and Central America there are only the less comprehensive keys of Calvert (1901, 1902a, 1903, 1907) and a modified, up-to-date volume (Förster, 2001) for Central America. Heckman (2008) provided keys to species for the vast South American continent, but they are mostly unreliable because they were taken from secondhand sources and repeat numerous errors. A succinct key for South American genera (von Ellenrieder & Garrison, 2009) was recently published, but it does not incorporate the latest generic taxonomic changes in the suborder. Lencioni (2005, 2006) provided illustrated keys for Brazilian genera only. Research in the neotropical Odonata by Latin American students has considerably intensified during the past twenty years. However, in order to identify material successfully, students of the order still must rely on primary literature or have access to a synoptic collection. Taxonomic knowledge of Zygoptera has lagged behind that of other orders of insects even more than Anisoptera in South America. With few exceptions (Pseudostigmatidae), this is most likely due to their small size, fragility, and unattractiveness to the general collector, since preserved material often undergoes significant postmortem discoloration. Because there is no comprehensive treatment allowing for the identification of neotropical damselflies, an illustrated key should greatly facilitate and accelerate taxonomic and ecological studies of the order in this rich geographic region. We believe that this book will be a reliable reference source for identification of damselflies for limnologists, ecologists, and other biologists relatively unfamiliar with these insects, and will further encourage research in this region. This work attempts to provide keys to adults, supported by abundant illustrations, to genera of damselflies (suborder Zygoptera) from anywhere in the New World. We are well aware that our goal of allowing nonspecialists or those little familiar with entomology to properly place specimens correctly to genus using our keys will not always be realized. Future studies of vastly unexplored areas, especially in South America, will augment species and genera, rendering our keys out of date. Still, our book should allow biologists to determine the existence of undescribed taxa by comparison with the keys, illustrations, and references to literature, which would otherwise not be possible. All the keys produced for this book using the DELTA program are open-ended, and should allow for the inclusion of newly described genera. Almost all illustrations and wing scans are from preserved material we have personally examined. As in our first volume, readers will find a strong bias in supportive illustrations toward the Meso- and South American fauna. Because of the relative disparity in the knowledge of North American versus Meso- and South American faunas, we have felt justified in concentrating our efforts on the less known Neotropical region. We have steered a conservative course with regard to recognition of families and genera. Several authors (Carle, 1982; Bechly, 1996; Trueman, 1996; Rehn, 2003; Bybee, Ogden, Branham, and Whiting, 2008; Carle, Kjer, and May, 2008), based on phylogenetic analyses, have shown the existing classification of the suborder to be partially artificial. However, phylogenetic relationships and familiar concepts within the suborder are far from resolved, and further research will most likely help build stronger hypotheses of relationships reflecting a natural classification. Since our purpose in this book is the identification of taxa, we have refrained from deviating from most of the currently recognized families and genera, although we provide references and comments regarding phylogenetic relationships among families when known. Although we provide brief summaries and references on habits and other aspects of biology for each genus, we have refrained from including sections on the general biology and ecology of Odonata in this volume. A standard reference for this is Tillyard (1917), and the updated and thorough volumes by Corbet (1999) and Córdoba- Aguilar (2008) will provide the interested student with information on the biology of Odonata in general.