Phylogenetic relationships of genus Nothofagus: The role of Antarctic fossil leaves

VENTO, BARBARA; AGRAIN, FEDERICO; PUEBLA, GRISELDA; PINZON, DIEGO

ACTA PALAEONTOLOGICA POLONICA

INST PALEOBIOLOGII PAN

Lugar: Varsovia; Año: 2023

0567-7920

The genus Nothofagus has a rich fossil record and an important number of living species distributedexclusively in the Southern Hemisphere. Many attempts have been made to clarify the phylogeneticrelationships of Nothofagus but only a few works have included fossil specimens in a phylogenetic frameworkfor a more accurate resolution. Fossil leaves play an important role in the evolutionary process and are anecessary complement in phylogenetic studies. Fossils of Nothofagus have been found in sediments ofAntarctica, Australia, New Zealand, New Caledonia, Papua New Guinea, and South America., and Australasia.Here, we performed a phylogenetic analysis including fossils from these areas and examined the characterevolution, especially those referred to the morphology of the leaf. Fossil leaves of Antarctica were revised andincluded in the analysis for the first time. Our results support the monophyly of the four current recognizedsubgenera, and novel relationships between fossils and living taxa are discussed. Morphological features offossil leaves showed differences, especially, in the teeth shape, size, and secondary venation pattern probablyrelated to past climate conditions. The most ancient leaves were recorded in the Late Cretaceous of Antarcticaand placed in subgenera Lophozonia and Fuscospora. Brassospora and Nothofagus are younger clades withdistinctive plesiomorphic leaf morphological features. The morphological leaf characters proposed, and theinclusion of a considerable number of fossils in our analysis allowed us to establish a more precise study of theevolutionary history of Nothofagus.