ABSTRACT
Modern snake lizards, distributed as they are into their extant crown clades, can be traced backward in time through a patchy fossil record that begins ∼60 million years ago in the early part of the Cenozoic in the Paleocene and Eocene epochs. The problem is, however, that form taxa are not sufficient for defining ancient snake lizard taxon concepts, but rather are concept fragments of incomplete snake lizard fossils, and in the case of vertebral form taxa, are exceptionally uninformative. The fossil record of snake lizards in the later part of the Cretaceous, and into the early Cenozoic, particularly from Laurasia, is largely restricted to isolated vertebral remains, most of which have been assigned to the vertebral form taxon Coniophis. The preserved anatomy of the type vertebra contains diagnostic morphologies to allow recognition of the element as belonging to a snake lizard: zygosphenes and zygantra are present and well developed; the neural canal, like Simoliphis rochebrunei displays trefoil outline.
