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New genus of Cupressaceae from the Upper Cretaceous of Patagonia (Argentina) fills a gap in the evolution of the ovuliferous complex in the family
Authors:Ana Andruchow-Colombo  María A. Gandolfo  Ignacio H. Escapa  Néstor R. Cúneo
Affiliation:1. LH Bailey Hortorium, Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca 14853 NY, USA;2.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Museo Paleontológico Egidio Feruglio (MEF), Av. Fontana 140, Trelew9100 Chubut, Argentina;Author for correspondence. E‐mail: ana.andruchow.colombo@gmail.com; aa848@cornell.edu
Abstract:The conifer family Cupressaceae encompasses seven subfamilies. Five of them were once considered to constitute the family Taxodiaceae, later eliminated because of its paraphyletic nature but remaining as an informal category for early-diverging Cupressaceae lineages. Among the taxodiaceous subfamilies, Athrotaxoideae shows a unique morphology in its ovuliferous complexes (OCs) and a phylogenetically unexplored fossil record. We describe the new genus and species Patagotaxodia lefipanensis, based on OC adpressions associated with leafy branches collected at the Maastrichtian section of the Lefipán Formation (Patagonia, Argentina), and we refer it to Athrotaxoideae. We include Patagotaxodia in total evidence phylogenetic analysis to test its affinity, and we recover it within the subfamilies Athrotaxoideae or Cunninghamioideae. However, we argue that the characters supporting the athrotaxoid affinity are more meaningful in a taxodiaceous systematic context. This placement is also supported by taxon inclusion-exclusion experiments. We discuss the position of other Cretaceous athrotaxoid records. With basis on the morphological insights provided by the OC morphology of extant and extinct Athrotaxoideae, we study the evolution of the OC morphology in the family in a phylogenetic context and discuss the results in the light of the fossil record of the family. We discuss how and when the different morphologies appeared in the family. Based on phylogenetic, temporal, morphological, and ontogenetic evidence, we conclude that the OC morphology shown by the subfamily Athrotaxoideae is intermediate between two of the most common morphologies within extant and extinct Cupressaceae species, one of which would show adaptative advantages over basal morphologies.
Keywords:Athrotaxis   Athrotaxoideae   Cunninghamioideae   Cupressaceae Phylogeny   Elatides   ovuliferous complex evolution   Patagotaxodia   Protodammara   seed cone evolution   Taxodiaceae  
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