Snakes of the Guianan region
Memórias do Instituto Butantan , Volume 46 p. 219- 254
The study of snaks from the Guianan region got an early start in 1705 when several species were pictured by Merian. As relatively large proportion of the snakes described by Linnaeus originated from Surinam. Interest for and knowledge of this group of animals steadily increased in the 18th and 19th century (80 species known at the turn of the century), but only in the second part of the 20 th century detailed studies of snake faunas from (part of) the Guianan region appeared. No such study for the entire area has been published till now. At present a total of 134 species of snakes, belonging to 159 taxa, is known. Only 19.4% is endemic, the majority (43.4%) belong to species with an Amazonian distribution. Seventeen species (12.7%) are venemous, ten belonging to the Elapidae, seven to the Crotalidae. Several taxonomic problems are discussed, Cercophie auratus (Schlegel) is restored as a valid taxon and redescribed. Analysis of available distribution data shows that forest snakes are fairly evenly distributed throughout Amazonia and Guiana. Snakes restricted to open formations are spread evenly throughout Guiana, but most of them are absent in western Amazonia. When taking together ubiquists and snakes restricted to open formations there is a fair resemblance between the faunas of Guiana and .Iquitos, but only a moderate one between Santa Cecilia and Guiana,possibly reflecting the influence of species belonging to the Andes foothill fauna (Napo refuge). Within Guiana apparently there are no unsurmountable barriers to snakes, the differences that are observed between the western and eastern/Brazilian part can be explained. by the presence of species barely raching these areas. Probably these species are still in the process of expanding their range.