Lizard phylogeography from Patagonia: replicated patterns of vicariance and range expansion

MORANDO, M.; A. CAMARGO; AVILA, L.J.; SITES, JR. J. W.

Curitiba

Congreso; IX Congreso Latinoamericano de Herpetología; 2011

Sociedad Brasilera de Herpetologia-Instituto Neotropical-Museo de Historia Natural

There are replicated phylogeographic patterns in different clades of Patagonian lizards, based on the mitochondrial marker cyt-b. First, for five species, there are sister haploclades distributed North and South of the Somuncurá Plateau, suggesting a common vicariant event. We did comparative analyses in these lineages to test for temporal congruence based on the following taxa: L. bibronii, H. darwinii, L. bellii, L. melanops, L. petrophilus. Second, for three of these we tested for a simultaneous southern expansion: L. bibronii, L. fitzingerii, H. darwinii. We used MrBayes to estimate parameters for different models with 1 million simulations for each. For both patterns there is a strong signal for a single event that affected all lineages and occurred very recently (mean time ~6,000 y.a.) and probably simultaneously, or the southern expansion shortly after the N-S Somuncurá divergence. After the last glacial maximum, mean temperature increased rapidly and considerably and sea level rises covered the same amount of land now above sea level, likely pushing easternmost populations towards the west and south. As these populations encountered the Somuncurá Plateau, they split into northern and southern clades, and a third wave of migration further south into land previously covered by permafrost. In these lineages there is higher genetic diversity the east coast, supporting the idea of eastern refugia during glacial times.