Temporal range: Early Eocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Bipedidae
Genus: Anniealexandria
Smith, 2009
Species: A. gansi
Binomial name
Anniealexandria gansi
Smith, 2009

Anniealexandria is an extinct genus of amphisbaenian lizard known by the type species Anniealexandria gansi from the earliest Eocene of Wyoming. Anniealexandria is the only known member of the family Bipedidae in the fossil record, which otherwise only includes the extant genus Bipes from Mexico. It was named in 2009 in honor of Annie Montague Alexander, founder of the University of California Museum of Paleontology. Remains of Anniealexandria are known only from a single fossil locality in the Bighorn Basin called Castle Gardens, but within the locality its fossils are common in the Willwood Formation, usually consisting of isolated jaw bones and vertebrae. Anniealexandria seems to have been a common component of a paleofauna that included fifteen other lizard species and existed in western North America during a period of global warming in the latest Paleocene and earliest Eocene.

Below is a cladogram from Longrich et al. (2015) showing the phylogenetic relationships of Anniealexandria:




Chthonophis subterraneus

Oligodontosaurus spp.



Anniealexandria gansi

Bipes spp.

Cadea blanoides

Todrasaurus gheerbrandti


Trogonophis wiegmanni

Diplometopon zarudnyi

Agamodon anguliceps