Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
Department of Biological Sciences, California State Polytechnic University-Humboldt, Arcata, CA, USA.
J Exp Bot. 2022 Jul 16;73(13):4273-4290. doi: 10.1093/jxb/erac137.
Systematics reconstructs tempo and mode in biological evolution by resolving the phylogenetic fabric of biodiversity. The staggering duration and complexity of evolution, coupled with loss of information (extinction), render exhaustive reconstruction of the evolutionary history of life unattainable. Instead, we sample its products-phenotypes and genotypes-to generate phylogenetic hypotheses, which we sequentially reassess and update against new data. Current consensus in evolutionary biology emphasizes fossil integration in total-evidence analyses, requiring in-depth understanding of fossils-age, phenotypes, and systematic affinities-and a detailed morphological framework uniting fossil and extant taxa. Bryophytes present a special case: deep evolutionary history but sparse fossil record and phenotypic diversity encompassing small dimensional scales. We review how these peculiarities shape fossil inclusion in bryophyte systematics. Paucity of the bryophyte fossil record, driven primarily by phenotypic (small plant size) and ecological constraints (patchy substrate-hugging populations), and incomplete exploration, results in many morphologically isolated, taxonomically ambiguous fossil taxa. Nevertheless, instances of exquisite preservation and pioneering studies demonstrate the feasibility of including bryophyte fossils in evolutionary inference. Further progress will arise from developing extensive morphological matrices for bryophytes, continued exploration of the fossil record, re-evaluation of previously described fossils, and training specialists in identification and characterization of bryophyte fossils, and in bryophyte morphology.
系统发育学通过解析生物多样性的系统发育结构来重建生物进化的时空调控和模式。进化的时间跨度和复杂性令人惊愕，再加上信息的丢失（灭绝），使得对生命进化历史的详尽重建变得不可能。相反，我们对其产物（表型和基因型）进行采样，以生成系统发育假说，然后我们会根据新数据对这些假说进行连续评估和更新。进化生物学领域目前的共识强调在综合证据分析中整合化石，这需要深入了解化石的年龄、表型和系统亲缘关系，并建立一个将化石和现生物种统一起来的详细形态框架。苔藓植物是一个特殊的例子：它们具有悠久的进化历史，但化石记录稀少，表型多样性涵盖小的尺寸尺度。我们回顾了这些特点如何影响苔藓植物系统发育学中对化石的纳入。苔藓植物化石记录的匮乏主要是由表型（植物体小）和生态限制（贴地丛生的种群）以及不完全的探索驱动的，这导致了许多形态上孤立、分类上模棱两可的化石类群。然而，一些精美的保存实例和开创性的研究表明，将苔藓植物化石纳入进化推断是可行的。进一步的进展将来自于为苔藓植物开发广泛的形态矩阵，对化石记录的持续探索，重新评估以前描述的化石，以及对苔藓植物化石的鉴定和特征描述以及苔藓植物形态学进行培训。
