The U.S. Fish and Wildlife Service (Service) has announced the availability of a revised recovery plan for the pallid sturgeon (Scaphirhynchus albus), a species that is found in the Missouri and Mississippi River basins, has been described as having a "unique dinosaur-like appearance," and has been listed as endangered since 1990.  As summarized by the Service, the revised recovery plan updates the "current understanding of the species life history requirements, identifies probable threats that were not originally recognized, includes revised recovery criteria, and based on improved understanding of the species, describes those actions believed necessary to eventually delist the species."  The Service believes that the pallid sturgeon "are an important indicator of the health of several of America's largest rivers, and represent a unique piece of America's natural history, with fossil ancestors dating back over 70 million years."  The original recovery plan was drafted in 1993.