Feldberg et al_Liverworts from Cretaceous amber

DNA-based analyses as well as the fossil record indicate that liverworts date back to the early Paleozoic, but diverse specimens of life-like three-dimensional fossils only occur as amber inclusions from the mid-Cretaceous onwards. Some Albian-Cenomanian ambers preserve elements of a diverse biota that existed during the rise of angiosperms, a time of fundamental change in terrestrial ecosystems that likely affected epiphytic taxa. Recent analyses have provided important insight into the phylogenetic diversification and morphological evolution of liverworts. They suggest that the mid- to Late Cretaceous was a transitional time with a significant species turnover. Here, we review all currently recognized leafy liverwort species from Cretaceous ambers based on the examination of previously described specimens as well as newly discovered amber inclusions. We provide a survey of all Cretaceous, amber-preserved liverwort species, including a determination key. The study of 26 new fossils from Kachin amber, including fertile material, enabled us to emend descriptions for Frullania cretacea, F. baerlocheri, and Protofrullania cornigera. Mid-Cretaceous Frullaniaceae often possess some characters and character combinations that are absent in extant representatives, substantiating the assumption of a lineage turnover in the Cretaceous. Among the new fossils is Radula heinrichsii sp. nov., which expands the number of Cretaceous, amber-preserved liverwort species to nine.

基于 DNA 分析和化石记录，苔藓植物可追溯至古生代早期，然而，栩栩如生的三维化石标本仅在白垩纪中期的琥珀中作为包含物出现。一些阿普利安-森诺曼阶的琥珀保存了在被子植物兴起时期存在的丰富生物群落元素，这一时期是陆地生态系统的根本变革时期，可能对附生植物类群产生了影响。近期的研究为苔藓植物的系统发育多样化和形态进化提供了重要的见解。研究表明，从中白垩纪至晚白垩纪是一个过渡时期，物种发生了显著更替。在此，我们回顾了基于对先前描述的标本以及新发现的琥珀包含物的考察，目前所认可的来自白垩纪琥珀的所有叶状苔藓植物物种。我们提供了对所有白垩纪琥珀保存的苔藓植物物种的概述，并附有鉴定关键。对卡钦琥珀中 26 个新化石的研究，包括繁殖材料，使我们能够修订 Frullania cretacea、F. baerlocheri 和 Protofrullania cornigera 的描述。中白垩纪的 Frullaniaceae 通常具有一些在现存代表中不存在的特征和特征组合，从而证实了白垩纪谱系更替的假设。在新化石中，包括 Radula heinrichsii 新种，将白垩纪琥珀保存的苔藓植物物种数量增加到九种。