The anatomy of the upper cretaceous snake Najash rionegrina Apesteguia & Zaher, 2006, and the evolution of limblessness in snakes

Author(s)

Zaher, Hussam ^[1] ; Apesteguia, Sebastian ^[2] ; Agustin Scanferla, Carlos ^[3]

Affiliation

^[1] Univ Sao Paulo, Museu Zool, BR-04263000 Sao Paulo - Brazil

^[2] Univ Maimonides, Fdn Hist Nat Felix Azara CEBBAD, RA-1405 Buenos Aires, DF - Argentina

^[3] Museo Argentino Ciencias Nat Bernardino Rivadavia, Lab Anat Comparada & Evoluc Vertebrados, RA-1405 Buenos Aires, DF - Argentina

• Document type: Journal article
• Source: ZOOLOGICAL JOURNAL OF THE LINNEAN SOCIETY; v. 156, n. 4, p. 801-826, AUG 2009.
• Web of Science Citations: 38

Abstract

Najash rionegrina Apesteguia \& Zaher, 2006, a terrestrial fossil snake from the Upper Cretaceous of Argentina, represents the first known snake with a sacrum associated with robust, well-developed hind limbs. Najash rionegrina documents an important gap in the evolutionary development towards limblessness, because its phylogenetic affinities suggest that it is the sister group of all modern snakes, including the limbed Tethyan snakes Pachyrhachis, Haasiophis, and Eupodophis. The latter three limbed marine fossil snakes are shown to be more derived morphologically, because they lack a sacrum, but have articulated lymphapophyses, and their appendicular skeleton is enclosed by the rib cage, as in modern snakes. (AU)

• FAPESP's process: 02/13602-4 - Evolution of the southeastern Brazilian reptile fauna from Cretaceous: paleontology, phylogeny and biogeography
• Grantee: Hussam El Dine Zaher
• Support type: BIOTA-FAPESP Program - Thematic Grants