Darlim Gustavo, Höhna Sebastian
GeoBio-Center LMU, Ludwig-Maximilians-Universität München, Munich, Germany.
Department of Earth and Environmental Sciences, Palaeontology and Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany.
Proc Biol Sci. 2025 Mar;292(2043):20250091. doi: 10.1098/rspb.2025.0091. Epub 2025 Mar 19.
Incomplete taxon sampling due to underestimation of present-day biodiversity biases diversification analysis by favouring slowdowns in speciation rates towards the recent time. For instance, in diversification dynamics studies in Crocodylia, long-term low net-diversification rates and slowdowns in speciation rates have been suggested to characterize crocodylian evolution. However, crocodylian cryptic diversity has never been considered. Here, we explore the effects of incorporating cryptic diversity into a diversification dynamics analysis of extant crocodylians. We inferred a time-calibrated cryptic-species-level phylogeny using cytochrome sequences of 45 lineages compared with the formally recognized 26 crocodylian species. Diversification rate estimates using the cryptic-species-level phylogeny show increasing speciation and net-diversification rates towards the present time, which contrasts with previous findings. Cryptic diversity should be considered in future macroevolutionary analyses; however, the representation of cryptic extinct taxa represents a major challenge. Additionally, further investigation of crocodylian diversification dynamics under different underlying genomic data is encouraged upon advances in population genetics. Our case study adds to the diversification dynamics knowledge of extant taxa and demonstrates that cryptic species and robust taxonomic assessment are essential to study recent biodiversity dynamics with broad implications for evolutionary biology and ecology.
由于对当今生物多样性的低估导致分类单元抽样不完整，这有利于近期物种形成速率的放缓，从而使多样化分析产生偏差。例如，在鳄目动物的多样化动态研究中，长期低净多样化速率和物种形成速率的放缓被认为是鳄目动物进化的特征。然而，鳄目动物的隐性多样性从未被考虑过。在这里，我们探讨将隐性多样性纳入现存鳄目动物多样化动态分析的影响。我们使用45个谱系的细胞色素序列推断了一个时间校准的隐性物种水平系统发育树，并与正式认可的26种鳄目动物物种进行了比较。使用隐性物种水平系统发育树的多样化速率估计显示，目前物种形成和净多样化速率在增加，这与之前的发现形成了对比。在未来的宏观进化分析中应考虑隐性多样性；然而，隐性灭绝分类单元的代表性是一个重大挑战。此外，随着群体遗传学的进展，鼓励对不同基础基因组数据下的鳄目动物多样化动态进行进一步研究。我们的案例研究增加了对现存分类单元多样化动态的了解，并表明隐性物种和稳健的分类评估对于研究近期生物多样性动态至关重要，对进化生物学和生态学具有广泛影响。
