Paleobotany bears an invaluable source of knowledge for understanding the history of the biodiversity that we protect and care for today. This discipline is recognized as a source of information on physical, ecological, and biological events and processes that occurred in the past and are maintained today, but whose occurrences must be interpreted necessarily, and sometimes with limitations, solely from the lithosphere. The importance of studying past life from Mexico and addressing fossil plant reconstruction is highlighted to understand modern biodiversity. Fossils in Mexico have been studied marginally but contain valuable information to understand the history of biodiversity, both in Mexico and globally. We examined the extent to which Mexican fossils can contribute to understanding the origin and development of biological processes through time, and how past plant biodiversity in Mexico compares with the extant one. We used two sources to address these questions: (i) ideas on biological processes as seen through the fossil record, and (ii) fossils known from Mexico. Examples are given of how fossils, morphology, anatomy, and numerical methods, as well as genetics and physiology, illuminate each other to generate solid botanical concepts. The abundant and widely distributed outcrops with fossil plants suggest that further studies on Mexican material will be influential for varied biological hypotheses related to the origin and history of biodiversity. Mexican fossil plants and their scarce sampled localities are open to further investigation that will complement hypotheses on the historic discussion of biological processes.

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Cannabaceae (Urticalean Rosids clade) is a small family with ten genera and a wide distribution in tropical and temperate regions worldwide. A complete understanding of the history of the lineage is fundamental to the integration of its fossil record, which needs to be better documented in low latitudes of North America. This work recognizes a new species, Aphananthe manchesteri Hernández-Damián, Rubalcava-Knoth et Cevallos- Ferriz sp. nov. (Cannabaceae), from the Miocene amber deposits of Simojovel de Allende, Chiapas, Mexico, based on a flower analyzed with reflected light and CT-scanning. Flowers of Cannabaceae are generally staminate or pistillate and small; staminate flowers have five sepals and opposite five stamens, and a pubescent pistillode, such as the fossil. However, the presence of three unguiculate and two ovate sepals with a puberulent surface are characteristics that allow its recognition as Aphananthe, the fossil is morphologically similar to Aphananthe monoica, an extant species that grows along the Pacific coast of Mexico. The presence of Aphananthe manchesteri sp. nov. in southern Mexico during the middle-early Miocene, ~23–15 Ma ago, supports the history of the lineage in lowlatitude North America, representing an expansion of the Boreotropical Flora. It adds to the taxonomical diversity of angiosperms preserved in Mexican amber, comparable with amber deposits from the Dominican Republic, where another anemophilous extinct species member of the Urticalean Rosids clade has been reported. This coincidence further supports the development of similar plant communities between these fossiliferous localities.

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