Oral Paper
Paleobotany
Tracing the fossil diversity of the conifer family Podocarpaceae through the ages
Presenting Author
Ana Andruchow-Colombo
Description
The Podocarpaceae are a morphologically diverse conifer family that have a cryptic fossil record, reported since the Permian. We reviewed the fossil record of Podocarpaceae, tested the affinities of the oldest records using phylogenetic analyses, compiled macrofossil occurrence records, and investigated the diversity, distribution, and morphology of Podocarpaceae through time. We found that Permian, Triassic, and some Jurassic fossils referred to Podocarpaceae should not be placed in the family. We performed total-evidence phylogenetic analyses, sampling all major conifer lineages, to analyze the positions of three genera previously assigned to Podocarpaceae that have been used as calibration points for the family —the Triassic Rissikia, and the Jurassic Nothodacrium and Mataia. We recover Rissikia and Nothodacrium as stem-group conifers, and the Jurassic Mataia as part of the stem group of the order Araucariales (Podocarpaceae + Araucariaceae). We conclude that the earliest reliable Podocarpaceae occurrences are from the Jurassic of both hemispheres, have scale-like leaves, belonging exclusively to extinct genera. The majority of living genera appear in the record between the Late Cretaceous and early Cenozoic. Most extant leaf morphologies appear in the Early Cretaceous, coeval with angiosperm diversification, consistent with the hypothesis that expanded leaves in Podocarpaceae are adaptive responses for light harvesting in today’s angiosperm-dominated environments.