UNASSIGNED: We used recent tectonic models to code extant and fossil squamate distributions occurring on nine discrete plates for 9,755 species, with Jurassic and Cretaceous fossil constraints from three extinct lineages. We modeled ancestral ranges for crown Squamata from an extant-only molecular phylogeny using a suite of biogeographic models accommodating different evolutionary processes and fossil-based node constraints from known Jurassic and Cretaceous localities. We hypothesized that the best-fit models would not support a full Pangaean distribution (i.e., including all areas) for the origin of crown Squamata, but would instead show regionalization to specific areas within the fragmenting supercontinent, likely in the Northern Hemisphere where most early squamate fossils have been found.
UNASSIGNED: Incorporating fossil data reconstructs a localized origin within Pangaea, with early regionalization of extant lineages to Eurasia and Laurasia, while Gondwanan regionalization did not occur until the middle Cretaceous for Alethinophidia, Scolecophidia, and some crown Gekkotan lineages. While the Mesozoic history of extant squamate biogeography can be summarized as a Eurasian origin with dispersal out of Laurasia into Gondwana, their Cenozoic history is complex with multiple events (including secondary and tertiary recolonizations) in several directions. As noted by previous authors, squamates have likely utilized over-land range expansion, land-bridge colonization, and trans-oceanic dispersal. Tropical Gondwana and Eurasia hold more ancient lineages than the Holarctic (Rhineuridae being a major exception), and some asymmetries in colonization (e.g., to North America from Eurasia during the Cenozoic through Beringia) deserve additional study. Future studies that incorporate fossil branches, rather than as node constraints, into the reconstruction can be used to explore this history further.
■我们使用最近的构造模型来编码9,755种物种在9个离散板块上发生的现存和化石角化分布,侏罗纪和白垩纪的化石限制来自三个灭绝的谱系。我们使用一套生物地理模型从现存的仅分子系统发育中模拟了冠状鳞茎的祖先范围,该生物地理模型可适应已知侏罗纪和白垩纪地区的不同进化过程和基于化石的节点约束。我们假设最佳拟合模型不会支持完整的Pangaean分布(即,包括所有区域)对于冠状鳞茎的起源,而是会显示出分裂的超大陆内特定区域的区域化,可能在北半球发现了大多数早期角化化石。
■结合化石数据重建了Pangaea内的局部起源,随着现存谱系的早期区域化到欧亚大陆和劳拉西亚,虽然直到白垩纪中期才出现冈瓦南地区的阿列斯虫,斯科普里菌,和一些王冠Gekkotan血统。尽管现存的中生代泥质生物地理学历史可以总结为欧亚起源,从Laurasia散布到Gondwana,他们的新生代历史很复杂,在多个方向上发生了多个事件(包括二级和三级重新定居)。正如以前的作者所指出的那样,狼人可能利用了过度的陆地范围扩张,陆桥殖民化,和跨洋扩散。热带冈瓦纳和欧亚大陆拥有比北方更古老的血统(莱茵科是一个主要的例外),和殖民中的一些不对称(例如,新生代期间从欧亚大陆到北美洲,经过柏林根)值得进一步研究。未来的研究结合了化石分支,而不是作为节点约束,进入重建可以用来进一步探索这段历史。