Museum of Paleontology and Department of Earth and Environmental Sciences, University of Michigan, 1105 N. University Ave, Ann Arbor, MI 48109-1079, U.S.A.
Biol Rev Camb Philos Soc. 2019 Apr;94(2):662-699. doi: 10.1111/brv.12473. Epub 2018 Oct 19.
Widespread fish clades that occur mainly or exclusively in fresh water represent a key target of biogeographical investigation due to limited potential for crossing marine barriers. Timescales for the origin and diversification of these groups are crucial tests of vicariant scenarios in which continental break-ups shaped modern geographic distributions. Evolutionary chronologies are commonly estimated through node-based palaeontological calibration of molecular phylogenies, but this approach ignores most of the temporal information encoded in the known fossil record of a given taxon. Here, we review the fossil record of freshwater fish clades with a distribution encompassing disjunct landmasses in the southern hemisphere. Palaeontologically derived temporal and geographic data were used to infer the plausible biogeographic processes that shaped the distribution of these clades. For seven extant clades with a relatively well-known fossil record, we used the stratigraphic distribution of their fossils to estimate confidence intervals on their times of origin. To do this, we employed a Bayesian framework that considers non-uniform preservation potential of freshwater fish fossils through time, as well as uncertainty in the absolute age of fossil horizons. We provide the following estimates for the origin times of these clades: Lepidosireniformes [125-95 million years ago (Ma)]; total-group Osteoglossomorpha (207-167 Ma); Characiformes (120-95 Ma; a younger estimate of 97-75 Ma when controversial Cenomanian fossils are excluded); Galaxiidae (235-21 Ma); Cyprinodontiformes (80-67 Ma); Channidae (79-43 Ma); Percichthyidae (127-69 Ma). These dates are mostly congruent with published molecular timetree estimates, despite the use of semi-independent data. Our reassessment of the biogeographic history of southern hemisphere freshwater fishes shows that long-distance dispersals and regional extinctions can confound and erode pre-existing vicariance-driven patterns. It is probable that disjunct distributions in many extant groups result from complex biogeographic processes that took place during the Late Cretaceous and Cenozoic. Although long-distance dispersals likely shaped the distributions of several freshwater fish clades, their exact mechanisms and their impact on broader macroevolutionary and ecological dynamics are still unclear and require further investigation.
广泛存在于淡水环境中的鱼类分支主要或完全局限于淡水环境，这是生物地理研究的一个关键目标，因为它们跨越海洋障碍的潜力有限。这些群体起源和多样化的时间尺度是检验大陆分裂塑造现代地理分布的趋同情景的关键测试。进化年代表通常通过分子系统发育的基于节点的古生物学校准来估计，但这种方法忽略了给定分类群的已知化石记录中编码的大部分时间信息。在这里，我们回顾了南半球具有离散陆地分布的淡水鱼类分支的化石记录。古生物学衍生的时间和地理数据用于推断塑造这些分支分布的可能生物地理过程。对于七个具有相对较好化石记录的现存分支，我们使用它们化石的地层分布来估计它们起源时间的置信区间。为此，我们采用了一种贝叶斯框架，该框架考虑了淡水鱼类化石随时间的非均匀保存潜力，以及化石层位的绝对年龄的不确定性。我们为这些分支提供了以下起源时间估计：肺鱼形目 [1.25-0.95 亿年前（Ma）]；总组骨舌鱼目（2.07-1.67 Ma）；脂鲤目（1.20-0.95 Ma；当排除有争议的白垩纪化石时，年轻的估计值为 97-75 Ma）；加拉辛科鱼类（2.35-21 Ma）；鲤形目（80-67 Ma）；鳗鲶科（79-43 Ma）；鲈形目（1.27-69 Ma）。尽管使用了半独立的数据，但这些日期与已发表的分子时标估计大多一致。我们对南半球淡水鱼类生物地理历史的重新评估表明，长距离扩散和区域灭绝会干扰和侵蚀先前的趋同驱动模式。许多现存群体的离散分布很可能是由于晚白垩世和新生代发生的复杂生物地理过程造成的。尽管长距离扩散可能塑造了几个淡水鱼类分支的分布，但它们的确切机制及其对更广泛的宏观进化和生态动态的影响仍不清楚，需要进一步研究。
