Divergence Dating and Biogeography of Xenosauridae Including Fossils as Terminal Taxa
Divergence Dating and Biogeography of Xenosauridae Including Fossils as Terminal Taxa
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DOI：
10.1670/21-068
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发表时间：
2022-09
影响因子：
0.8
通讯作者：
Riley Parks;S. Harrington;R. C. Thomson
中科院分区：
文献类型：
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作者：
Riley Parks;S. Harrington;R. C. Thomson
抽象的。异龙属（Xenosaurus）是一种胎生蜥蜴，其特征是扁平的身体，奇特的节状鳞片，以及极端的裂缝栖息生态。这一罕见而神秘的属中的物种分布在墨西哥和危地马拉的大部分地区。异龙是古代异龙科中唯一幸存的属，对该属成员的起源和地理历史知之甚少。为了解决这一问题，我们估计分歧时间在整个Xenosaurus下的出生-死亡模型，包括已发表的ddRADseq数据，形态数据的六个现存的和三个化石亲属属Xenosaurus，和化石出现的数据为三个化石亲属。据估计，皇冠异龙的年龄为3500万年，比该家族的主干年龄要年轻得多，这意味着灭绝率很高。墨西哥的分布和三个在北美洲西部的化石亲属的位置表明了一个从北到东南方向进化的新北起源。为了验证这一假设，我们进行了贝叶斯传播学分析下的扩散灭绝分支发生（DEC）模型，以估计整个属的历史范围和模式的扩散。地理分析的结果支持了这一历史性的由北向东南的运动。结合我们的多样化估计，我们的DEC结果表明，气候事件，如冷却在中新世和上新世可能塑造了分歧和目前的分布在Xenosaurus。
Abstract.— Middle-American knob scaled lizards of the genus Xenosaurus are viviparous lizards characterized by flattened bodies, peculiar knob-like scales, and extreme specialization to a crevice-dwelling ecology. Species within this rarely seen and enigmatic genus are distributed throughout much of Mexico and Guatemala. Xenosaurus is the sole surviving genus of the ancient family Xenosauridae and little is known about the origins and biogeographic history of members of the group. To address this deficit, we estimated divergence times across Xenosaurus under the fossilized birth–death model, including published ddRADseq data, morphological data for six extant and three fossil relatives to genus Xenosaurus, and fossil occurrence data for the three fossil relatives. Crown Xenosaurus was estimated to be 35 million years old, considerably younger than the stem age of the family, implying high rates of extinction. The distribution of Xenosaurus populations across Mexico and the location of the three fossil relatives in western North America suggest a Nearctic origin with a north to southeast direction of range evolution in Xenosaurus. To test this hypothesis, we performed a Bayesian biogeographic analysis under the Dispersal Extinction Cladogenesis (DEC) model, in order to estimate the historical ranges and patterns of dispersal across the genus. The results of the biogeographic analysis supported this historical north to southeast movement. In conjunction with our diversification estimates, our DEC results suggest that climatic events such as cooling during the Miocene and Pliocene may have shaped the divergence and current distributions in Xenosaurus.