摘要：

The Squamata, a vertebrate group that includes lizards, amphisbaenians and snakes, have inhabited Patagonia since the Late Cretaceous. The Mesozoic record comprises an iguanian, a scleroglossan and a great diversity of snakes that include, among others, the most primitive terrestrial forms. Snakes were also well diversified in the Palaeogene, with fossils of madtsoiids and boids (including the oldest record of the extant Boa) found as far south as 46°S, following the then dominant subtropical conditions in the region. The Palaeogene record comprises small, medium-sized and large forms. The only boids that persisted at the beginning of the Neogene are all small forms, suggesting colder temperatures than during the Palaeogene. The oldest South American colubrids made their first appearance at this time, reaching latitudes south of the current Patagonian distribution (50°S). The Neogene record also includes the first occurrence of extant iguanians (Pristidactylus and Liolaemus) and teiids (Tupinambis). The latter reached the southernmost distribution of its evolutionary history during the Miocene. The distribution of boids, colubrids and tupinambine teiids at higher latitudes than at present indicates warmer conditions during the Miocene. The uplift of the Patagonian Andes, followed by a decrease in temperature and an increase in desertification, induced a strong contraction in the distribution of tupinambine teiids to northern regions of Patagonia and even forced the complete disappearance of boids from this region. In contrast, these changes appear to have favoured the diversification of iguanian genera on both sides of the Patagonian Andes. 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 441457.Los Squamata (lagartos, anfisbenas y serpientes) habitan la Patagonia desde el Cretcico tardo. El registro Mesozoico comprende un iguanio, un esclerogloso, y una gran diversidad de serpientes que incluye las formas terrestres ms primitivas. Las serpientes estaban bien diversificadas durante el Palegeno, con madtsoideos y boidos (incluyendo el registro ms antiguo de la actual Boa) que alcanzaron altas latitudes (46 °S) siguiendo las condiciones subtropicales dominantes en la regin. En contraste con el Palegeno, que incluye formas peque±as, medianas y grandes, los nicos boidos que persisten a comienzos del Negeno son todas formas peque±as que sugieren temperaturas ms bajas que durante el Palegeno. Los ms antiguos colbridos sudamericanos son del Negeno, cuando alcanzan latitudes (50 °S) al sur de su actual distribucin. El registro del Negeno tambin incluye la aparicin de gneros actuales de lagartos iguanios (Pristidactylus y Liolaemus) y teidos (Tupinambis). Tupinambis alcanza la distribucin ms austral durante el Mioceno. La presencia de boidos, colbridos y teidos tupinambinos a mayores latitudes que en el presente indica condiciones ms clidas durante el Negeno. El levantamiento de los Andes Patagnicos, seguido por la disminucin de la temperatura y el incremento de la aridez, produjo una fuerte contraccin en la distribucin de teidos tupinambinos hacia el norte y la desaparicin total de boidos de Patagonia. En contraste, estos cambios parecen haber favorecido la diversificacin de los gneros de iguanios a ambos lados de los Andes.

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