An annotated key to the Neotropical Dragonflies. Book review.

PESSACQ, P

REVISTA CHILENA DE HISTORIA NATURAL

Sociedad de Biología de Chile

Lugar: Santiago; Año: 2008 vol. 81 p. 151 - 152

0716-078X

The Neotropical region, with more than 1600 described species, hosts the biggest biodiversity of Odonata in the world (Garrison, 1991; Bridges, 1994; Tsuda, 2000), reaching its maximum expression in central and northern South America. While North American Odonata has been well surveyed (if not completely) and several compilations and field guides exist (Biggs, 2004; Carpenter, 1991; Dunkle, 2000; Westfall & May, 1996; etc.); the opposite rules in Central and South America. Even when a wide number of species have been described in the last years, many more are still waiting to be discovered and no general keys or compilations for this region exist (with the exceptions of Borror, 1945 and Munz, 1919). In addition, Neotropical Odonata bibliography is widely scattered. In this sense, “Dragonfly Genera….” represents a huge step forward, besides offering us a key to all Neotropical genera known, it is also a magnificent compilation and an original framework. The book is divided into 12 chapters. The first one is an introduction dealing with some morphological aspects, methodology, collection and preservation; the second chapter includes a key to the families, and the remaining chapters deal with Neotropical Anisoptera families and Libellulidae subfamilies. Every family chapter starts with the geographical distribution, number of genera and species, and the family characterization followed by both male and female genera keys. The genera are extensively treated, including a complete  species synonymy list  (larval description references also included). All this followed by the main bibliography references, distribution, characterization, classification status, habitat and new species potential. A distribution map is also presented for each genus. A remarkable high percentage of species were directly examined as indicated on the species list. The keys, built with DELTA key-generating software (Dallwitz, paine and Zurcher, 2000), are clear and extensively supported with illustrations and scanning pictures. Keys were tested by biology students and not specialized entomologists on specimens from the Argentinean Patagonia, proving to be highly effective and user friendly. Even when genera identification is the main purpose of the book, the intrageneric variation is also described by including several species drawings,  therefore allowing many species to be identified. Over 1600 extremely explicative and artistic quality illustrations together with the keys constitute the core of the book. This book also provides through its synonymic lists an invaluable access to all main bibliography references. A remarkable aspect is the characterization and diagnosis of every family and genus; this information, mainly regarding to genera, is dispersed or absent in general bibliography.  The general morphology section (chapter 1, “what is a dragonfly?”), even thought it is adequate, it is also brief, and I would have expected a deeper treatment on the subject. The book has 24 color pictures, but in my opinion such an effort and such beautiful insects  deserve much more pictures. Some references in the text are not listed in the cited bibliography (i.e. Borror, 1945) and very few misspellings can be found. The Aeshnidae chapter is not referenced at the top of the page, as other chapters are.  In conclusion, this book becomes a fundamental study for every biologist and advanced naturalist who deals with or is interested in Neotropical dragonflies.