sentences:  Eocene rhineurids, such as "Spathorhynchus fossorium", are remarkably similar to the modern "Rhineura", suggesting very conservative evolution within the family.Unlike the Amphisbaenidae, which include round-headed, keeled, and shovel-snouted forms, the fossil rhineurids are exclusively of the shovel-snouted variety.The fossil rhineurids are known exclusively from North America, but show that the group once had a much wider distribution than the current range of "R. floridana", with species known from Colorado, Wyoming, South Dakota, Montana, and as far west as Oregon.