This key includes all of the 105 polyclad species that have been described in the literature from the Pacific Coast of North and Central America.  The classification of the polyclads follows the Faubel (1983, 1984) revision of the Polycladida.  Eight of the species included are in question and are designated as incertiae sedis, i.s., and one species as nomen nudum, n.n.

There is a species description for each of the 105 species which includes the classification of the species, literature reference and a description of the species.  The description of a species is condensed from the original description and includes the following: form, color, eyes, digestive system, and copulatory apparatus.   Three other items are included in the species description pages, distinguishing characters, distribution and holotype location.  When necessary there is a comments section included.  Diagrams for each species include a dorsal view of a whole specimen, usually a sagittal view of the copulatory apparatus and a dorsal diagram of the distribution of the eyes.  Pictures of the species are embedded in the description pages.  It should be emphasized that when describing a new species a study of the reproductive structures which requires serial sagittal sectioning of the specimen.

Other sections included are an Explanation of Text Symbols, Alphabetical List of Species and a Taxonomic List of the Species.  The Taxonomic list of the Species is divided into 2 sections.  The first section is Faubel’s Taxonomic Scheme with a listing of the species by their classification.  The second part of the Taxonomic Scheme is a comparison of Faubel’s scheme with Prudhoe’s scheme.

The geographic range of the species described is from Point Barrow, Alaska to the coast of Panama.  There are no distinct geographic boundaries for the polyclads as a number of species are known to have extensive ranges, such as Kaburakia excelsa Alaska to Newport, California while other species are known from only one location, Armatoplana reishi from the L.A. Harbor, California.  Two species were collected from sea mounts in the Cascadia Basin at depths of 2650m and three species have been collected in nueston tows west of Baja California and Panama.

The glossary defines the terms used in describing the structures of the species.  The terms are those that Faubel and Prudhoe used.  It seems that every researcher has a preferred term for a structure which adds to confusion when other researchers are trying to identify a specimen.

References are listed for articles that contain the descriptions of the 105 species.  In addition, there are references to handbooks (Brusca 1973 and 1980), guides (Gotshall 1994, Kerstitch 1989, and 2^nd edition with H. Bertsch ed. 2007), species keys (Holleman 1987 in Marine Invertebrates of the Pacific Northwest, Kozloff (ed.) and Holleman 2007 in The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon, J. Carlton (ed.), Intertidal Invertebrates of California (Morris, Abbott and Haderlie 1980).

I have not included polyclad web sites with the references.  There are two that may be helpful:  (1) Wolfgang Seifarth of the University of Heidelberg has a site “Marine Flatworms of the World”.  There are 30 photographs of specimens from the Pacific Coast Canada, of California and Mexico. The last additions to this site were in 2003.   Another web site where photographs have been posted is Nudi Pixel.  They have over 1,480 photographs of which over 600 are unidentified.  Most of the photographs are from the South Pacific, Philippines and the Indian Ocean.

I want to acknowledge David Behrens, Chris Grossman, D.W. Gotshall, Alex Kerstitch, G. Trevelyan, Department of Invertebrate Zoology and Geology’s photographic collection at the California Academy of Science, and Sanford University Press. They have given permission to include their photographs in the key.

I believe that the 105 species described comprise less than half the number of species of polyclads on the west coast of North and Central America.  I had the opportunity to spend time on the east and west coasts of the Gulf of California.  I collected and photographed a number of unknown species.  An example is a pseudocerotid that has been photographed numerous times and can be seen on the web sites Nudi Pixel and Marine Flatworms of the World.  It is has been identified as Pseudoceros bajae, which is now Cryptobiceros bajae,but it is not Cryptobiceros bajae.  Cryptobiceros bajae was described by Hyman, 1953, as tan to black dorsal surface with white spots extending to the margin on the dorsal surface.  When I collected specimens north of Puertocitos, Baja California the dorsal color was deep purplish brown with the margin darker to almost black.  The dorsal surface is covered with white and yellow dots.  The yellow dots are larger and more numerous than the white dots.  The darker marginal areas have fine white dots.  The species Cryptobiceros bajae described by Hyman had only white spots.  She would have included the presence of both white and yellow spots with the yellow spots being larger.  This unknown species is one of the largest polyclad I have ever collected, 10cm long and 6cm wide.   The pacific coasts of Mexico and Central America, Guatemala, Honduras, Nicaragua, Costa Rica and Panama, have not been systematically studied.

 

John J. Holleman

Research Associate

Department of Invertebrate Zoology and Geology

California Academy of Sciences

San Francisco, California