Gorscak Eric, O'Connor Patrick M
Department of Biological Sciences, Ohio University, 107 Irvine Hall, Athens, OH 45701, USA Ohio Center for Ecology and Evolutionary Studies, Irvine Hall, Athens, OH 45701, USA
Ohio Center for Ecology and Evolutionary Studies, Irvine Hall, Athens, OH 45701, USA Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, 228 Irvine Hall, Athens, OH 45701, USA.
Biol Lett. 2016 Apr;12(4). doi: 10.1098/rsbl.2015.1047.
Recent model-based phylogenetic approaches have expanded upon the incorporation of extinct lineages and their respective temporal information for calibrating divergence date estimates. Here, model-based methods are explored to estimate divergence dates and ancestral ranges for titanosaurian sauropod dinosaurs, an extinct and globally distributed terrestrial clade that existed during the extensive Cretaceous supercontinental break-up. Our models estimate an Early Cretaceous (approx. 135 Ma) South American origin for Titanosauria. The estimated divergence dates are broadly congruent with Cretaceous geophysical models of supercontinental separation and subsequent continental isolation while obviating the invocation of continuous Late Cretaceous continental connections (e.g. ephemeral land bridges). Divergence dates for mid-Cretaceous African and South American sister lineages support semi-isolated subequatorial African faunas in concordance with the gradual northward separation between South America and Africa. Finally, Late Cretaceous Africa may have linked Laurasian lineages with their sister South American lineages, though the current Late Cretaceous African terrestrial fossil record remains meagre.
最近基于模型的系统发育方法在纳入已灭绝谱系及其各自的时间信息以校准分歧日期估计方面有了扩展。在此,我们探索基于模型的方法来估计泰坦巨龙类蜥脚恐龙的分歧日期和祖先分布范围,泰坦巨龙类是一个已灭绝且全球分布的陆地类群,存在于白垩纪超级大陆广泛分裂的时期。我们的模型估计泰坦巨龙类起源于早白垩世(约1.35亿年前)的南美洲。估计的分歧日期与超级大陆分离及随后大陆隔离的白垩纪地球物理模型大致相符,同时避免了对白垩纪晚期连续大陆连接(如短暂陆桥)的援引。白垩纪中期非洲和南美洲姐妹谱系的分歧日期支持了半隔离的赤道以南非洲动物群,这与南美洲和非洲之间逐渐向北分离的情况一致。最后,晚白垩世的非洲可能将劳亚大陆谱系与其南美洲姐妹谱系联系起来,尽管目前晚白垩世非洲陆地化石记录仍然稀少。