An Updated Classification of the Recent Crustacea By J. W. Martin and G. E. Davis

Abstract

For anyone with interests in a group of organisms as large and diverse as the Crustacea, it is difficult to grasp the enormity of the entire taxon at one time. Those who work on crustaceans usually spe- cialize in only one small corner of the field. Even though I am sometimes considered a specialist on crabs, the truth is I can profess some special knowl- edge about only a relatively few species in one or two families, with forays into other groups of crabs and other crustaceans. Crabs are but a small picture of the overall diversity of the Crustacea. They rep- resent only one infraorder Brachyura within one order Decapoda within one superorder Eucarida within one subclass Eumalacostraca within one class Malacostraca of the six currently recognized classes of the Crustacea (as depicted herein). I am certain that this situation is similar for all other crustacean systematists, with the result that there are no living specialists who can truly claim to have an in-depth understanding of the Crustacea as a whole. This volume is an attempt to provide the reader, whether a seasoned systematist or a beginning stu- dent, with a glimpse into the enormous variety of extant crustaceans. The sheer number of categories that humans have constructed to contain and order this group is some indication of the incredible amount of morphological diversity they exhibit. But this is only a small part of the overall picture. Even if one were to grasp the full range of taxo- nomic diversity as presented in this classification, such knowledge would shed no light on the actual biology of these fascinating animals: their behavior, feeding, locomotion, reproduction; their relation- ships to other organisms; their adaptations to the environment; and other facets of their existence that fall under the heading of biodiversity. By producing this volume we are attempting to update an existing classification, produced by Tom Bowman and Larry Abele (1982), in order to ar- range and update the Crustacea collection of the Natural History Museum of Los Angeles County. This enormous and diverse collection contains an estimated four to five million specimens, making it the second largest collection of Crustacea in the Americas. While undertaking this task, it occurred to us that others might benefit from our efforts, and that perhaps a general update on the number and arrangement of the living crustacean families, along with an explanation of the systematic and classifi- catory changes suggested during the last two de- cades, might be a welcome addition to the litera- ture. I hope this volume is seen as nothing more than the briefest of introductions into an under- standing of crustaceans and that it might lead to further work not only on the relationships among crustaceans but also toward understanding the overall picture of crustacean biodiversity and natural history