... The Paleontological Society 2001 T he frog genus Xenopus is a distinctive component of the modern African batrachofauna. It is a member of the highly derived, exclusively aquatic Pipidae, a clade ( Cannatella and Trueb, 1988 ) that is currently restricted to Africa and South America. Xenopus today occurs...

... the presence of a crista dentalis and of a relatively unreduced pars facialis exclude it from Pipidae (Cretaceous–Recent, Africa and South America). The lack of teeth in Tyrrellbatrachus is notable because although tooth loss is widespread among extant anurans and has arisen independently multiple times...

...AMY C. HENRICI The Paleontological Society 2002 Amy C. Henrici and Ana Maria Báez. First occurrence of Xenopus (Anura: Pipidae) on the Arabian Peninsula: A new species from the Upper Oligocene of Yemen. Journal of Paleontology, 75:870–882 . In our paper on fossil frogs from Yemen...

... 2000 ; Rage and Roček 2003 ). Palaeobatrachidae are considered closely related to the extant Pipidae, a fact recognized as early as the second half of the nineteenth century by Cope (1865) and still accepted today (e.g., Cannatella and de Sá 1993 ). The main differences between the two...

...: intergeneric relationships of the aquatic frog family Pipidae (Anura) . Zoological Journal of the Linnean Society 94 : 1 – 38 . Cignoni , P. , M. Callieri...

... is incomplete. A good example is provided by the divergence date between Pipa and Xenopus , within Pipidae. Pipids are abundantly represented in the fossil record, but the oldest pipoids, from the Lower Cretaceous, may be stem-pipids that predate the divergence among the extant genera ( Trueb 1999 ; Báez...

... for distinguishing anuran and urodele ilia. For instance, the anterior portion of the iliac shafts in the Pipidae are enlarged due to their sliding articulation with the sacral diapophyses [ Van Dijk, 2002 ] and, thus, somewhat resemble the expanded dorsal end of the iliac shaft seen in many urodeles. Isolated...

... . Academic Press , London . Tinsley , R. C. , H. R. , Kobel , M. , and Fischberg , 1979 , The biology and systematics of a new species of Xenopus (Anura: Pipidae) from the highlands of Central Africa : Journal of Zoology (London) , 188 . 69 – 102 . Vézina , D. , 1991...

... (Bathonian to Recent); Pipidae (Hauterivian to Recent); Palaeobatrachidae (Valanginian to Pliocene); Rhynophrynidae (Tithonian (Henrici pers. comm.) to Recent); Pelobatidae (Tithonian to Recent); and Lepto- dactylidae (Santonian to Recent) (Milner 1993). Seven families have a post-K T fossil record only...