Decapod Crustacea of the Californian and Oregonian Zoogeographic Provinces
Total Page：16
File Type：pdf, Size：1020Kb
DECAPOD CRUSTACEA OF THE CALIFORNIAN AND OREGONIAN ZOOGEOGRAPHIC PROVINCES Mary K. Wicksten February 2008 http://repositories.cdlib.org/sio/lib/26/ a. General introduction Approximately 280 species of decapod crustaceans live along the west coast of North America between Puget Sound and Magdalena Bay, Baja California, Mexico. Species of the shrimp families Crangonidae, Hippolytidae and Pandalidae and crabs of the Cancridae, Lithodidae, Majidae and Paguridae are particularly abundant. Many of the genera and species either are unique to the North Pacific or are found only along the west coast of North America. The last major guide to the decapods of California or Oregon was Marine Decapod Crustacea of California, by W.L. Schmitt (1921). Schmitt's pioneering book, largely based on collections of the U.S. Fisheries steamer Albatross, now is badly out of date and difficult to obtain. Shallow-water species are mentioned in guidebooks to intertidal animals, such as those by Morris et al. (1980), Ricketts et al. (1985), and Smith and Carlton (1975). Good color photographs of shallow-water species, along with information on range and identifying features, can be found in the book by Jensen (1995). These works do not provide citations for the original descriptions or type localities, synonymies or other information needed by the specialist. There are no recent summaries or reviews of species of deeper benthic habitats and only one (Wicksten, 2002) listing of pelagic species. Revisions of the nomenclature, new systematic interpretations of families and higher taxa, descriptions of new species, range extensions and natural history information published since 1921 are scattered in the literature of at least seven nations and four languages. Many valuable works on decapods are old and unavailable except through major university libraries. Little is available on the internet. Even today, only the most meager details of anatomy and natural history are available for many species. Compared to other marine invertebrates, decapods tend to be large and recognizable. Larger crabs, shrimp and lobsters are fished commercially for food or bait. Many species are important in food webs, feeding on small mollusks, worms, crustaceans or detritus and in turn being eaten by fishes, birds, seals or sea lions. Intertidal species have been used in behavioral or physiological research on regeneration, color changes, respiration and symbiotic relationships. Interested visitors to kelp beds and tide pools photograph and observe decapods. One must identify a species in order to study it or label its photograph. Without the needed literature or training in the anatomy of decapod crustaceans, the interested biologist must seek out the few specialists who can identify northeastern Pacific decapods. The fauna of the northeastern Pacific differs greatly at the level of genera from that of tropical regions or the western Atlantic. A person familiar with decapods of other regions may have no idea where to find information on the fauna of the northeastern Pacific, especially if the pertinent literature is in Russian. It is my hope to remedy the lack of a technical guide to decapods of the warm and cold temperate regions of the northeastern Pacific. The format of the text follows that of Shrimps, Lobsters and Crabs of the Atlantic Coast, by A. Williams (1984). The work is focused on nomenclature and natural history of the species. Literature on mariculture, fisheries and physiology is not included. The text is directed to the biologist or advanced university student. b. Methods and Coverage The present work provides information on all decapods that have been reported from Puget Sound to Magdalena Bay, Baja California; including fresh water species. Coverage extends from the intertidal zone to the continental slopes and lower mesopelagic zone. For purposes of this book, pelagic species are included that might be collected within the territorial waters of the United States, northern Mexico and southwestern Canada and not in the open sea. Species that are known from only a single record, misidentifications, non- reproducing introductions and questionable or unverified records are included in the accounts of each family. The geographic area covered encompasses the Oregonian Zoogeographic Province, from Puget Sound to Point Conception, California; and the Californian Zoogeographic Province, from Point Conception to roughly Magdalena Bay (Brusca and Wallerstein, 1979). For species found in Puget Sound and to the north, consult the works of Kozloff (1974), Butler (1980) and Hart (1982). Species of western Mexico and the tropical eastern Pacific are covered by Hendrickx (1996, 1997), Hendrickx and Estrada-Navarrete (1996) and Wicksten and Hendrickx (2003). Keys are provided for all families, and species if more than one species belongs to that family. The keys are based on identification features that can be used to distinguish between the families and species in the area of coverage. Classification follows Bowman and Abele (1982), Hendrickx (1996) and Martin and Davis (2001) except as noted. For a world-wide key to genera of caridean and stenopodidean shrimp, consult Holthuis (1993). Common names for many shrimp species have been compiled by McLaughlin and Camp, 2005, but are not included here. Major synonymies are provided for each species. These include the citation of the original description and citations from major systematic works, widely-used checklists, textbooks and guidebooks, and shorter papers containing information on range, natural history or first records of occurrence in the area. The reader is referred to more extensive synonymies presented in systematic works where such exist. No new synonyms or descriptions of undescribed species are provided in this work. Descriptions are based on published works as mentioned in the synonymies and also examination of specimens in the collections of the United States Museum of Natural History, Smithsonian Institution; California Academy of Sciences, Scripps Institution of Oceanography and Los Angeles County Museum of Natural History (repository of the collections of the Allan Hancock Foundation of the University of Southern California). The descriptions present recognition characters that are useful for identification without dissection. The systematist interested in minute details of setae, mouthparts, etc. is advised to examine actual specimens to see these features. Some of the species are known from a few specimens in poor condition; others are known only from short and old descriptions, so the descriptions presented here vary in their length and degree of complexity. Drawings were based on actual specimens as much as possible. Where the drawing is based on a previous illustration, the source is cited. Color in life is based on published color plates, photographs and notes as well as field notes of living specimens. Range, depth and habitat are based on published information, field note and records from the collections mentioned previously. Latitude and longitude are given for locations away from easily located shore features. Any previously unpublished records include a station or collection catalogue number. Collections and descriptions of northeastern Pacific decapods go back to the early 1800’s. Some of the early biologists, such as Brandt and Owen, reported collecting localities that are easy to locate on a map today. Others were vague, giving locations such as “California”. I have given the type locality as was written in the original description. I also have indicated where a type locality was not specified. I have included remarks on taxonomy and natural history where such information will aid the reader in identifying a species. A few species have undergone extensive taxonomic revision; others have peculiar habits, morphological features or ecological relationships that are characteristic. Every effort was exerted to insure that this work was up-to-date at the time of publication. Most of the illustrations either were newly prepared for this work or were derived from recent and authoritative works. However, the reader is warned that many species, as mentioned in the text, can be variable in such features such as the number of spines, length of the rostrum, and size and shape of the chelipeds. The specific designation of some remains in question. The diligent biologist may find unknown variants within a species, previously unknown species, or synonyms. At present, few biologists have applied molecular or enzymatic techniques to the study of northeastern Pacific species. Such techniques could clarify the systematic relationships of many species-rich groups. The fauna of the continental slopes is largely unstudied between southern California and Oregon. c. Geographic distributions Before widespread human activities, freshwater decapods ranged from California to Washington, U.S.A. There are no records of freshwater decapods from northern Baja California prior to the twentieth century. Two species of Syncaris, freshwater shrimp endemic to California, occured in coastal streams. Native crayfish belonged to four species of Pacifastacus. The crayfish ranged into streams and rivers of the Coast, Sierra Nevada and Cascade Ranges as far east as Idaho. These cold-water decapods have their nearest relatives in Eurasia. Marine species of the area under consideration tend to have extensive ranges. The most wide- ranging decapods are pelagic shrimp of the families Benthesicymidae, Sergestidae, Oplophoridae and Pasiphaeidae.