The idea that South America was an island continent over most of the Cenozoic, during which its unusual mammalian faunas evolved in isolation, is outstandingly influential biogeography. Although large numbers recent fossil discoveries and related advances require original isolation concept be significantly modified, it still repeated much current literature. persistence inspired us to present here integrated paleobiogeographic account mammals, reptiles, plants from Jurassic Paleogene...

Premise of research. Phylogenetic relationships Araucariaceae (Coniferophyta, Araucariales) are revised on the basis first combined data matrix for family.Methodology. Taxon sampling includes 39 ingroup species (31 extant, 8 fossils) and outgroup all remaining conifer families. Five fossil Araucaria species, one genus Araucarites, two extinct genera Wairarapaia Emwadea were included in analyses. Character 23 genomic regions (19 plastid, 2 nuclear, mitochondrial) 62 morphological characters...

• Premise of the study: Agathis is an iconic genus large, ecologically important, and economically valuable conifers that range over lowland to upper montane rainforests from New Zealand Sumatra. Exploitation its timber copal has greatly reduced genus's numbers. The early fossil record comes entirely Australia, often presumed be area origin. no previous South America. Methods: We describe abundant macrofossils vegetative reproductive organs, middle Eocene rainforest paleofloras Patagonia,...

Evolutionary divergence-age estimates derived from molecular 'clocks' are frequently correlated with paleogeographic, paleoclimatic and extinction events. One prominent hypothesis based on data states that the dominant pattern of Southern Hemisphere biogeography is post-Gondwanan clade origins subsequent dispersal across oceans in a metaphoric 'Green Web'. We tested this idea against well-dated Patagonian fossils 19 plant lineages, representing organisms actually lived Gondwana. Most these...

Continental Triassic sequences in Antarctica are among the most continuous and best represented Gondwana. fossil plants have been collected sporadically from since beginning of twentieth century, but our knowledge vegetation during this time has dramatically increased last three decades. Here we review record as representatives natural groups sites along Transantarctic Mountains, using fossils evidence for successive vegetational changes through Triassic, taking into account that these plant...

We present a whole-plant concept for genus of voltzialean conifers on the basis compression/impression and permineralized material from Triassic Antarctica. The reconstruction individual organs is based combination organic connections, structural correspondences, similarities in cuticles epidermal morphologies, co-occurrence data, ex situ palynology. affiliated genera include trunks, branches, roots (Notophytum); strap-shaped leaves with parallel venation (Heidiphyllum compressions...

Premise of the Study The fossil record Agathis historically has been restricted to Australasia. Recently described fossils from Eocene Patagonian Argentina showed a broader distribution than found previously, which is reinforced here with new early Paleocene species Patagonia. No previous phylogenetic analyses have included species. Methods We describe macrofossils Patagonia vegetative and reproductive organs Danian, as well leaves affinities latest Maastrichtian. A total evidence analysis...

Premise of the Study Equisetum is sole living representative Sphenopsida, a clade with impressive species richness, long fossil history dating back to Devonian, and obscure relationships other pteridophytes. Based on molecular data, crown group age mid‐Paleogene, although fossils possible synapomorphies appear in Triassic. The most widely circulated hypothesis states that lineage derives from calamitaceans, but no comprehensive phylogenetic studies support claim. Using combined approach, we...

Sauropods, the giant long-necked dinosaurs, became dominant group of large herbivores in terrestrial ecosystems after multiple related lineages extinct towards end Early Jurassic (190–174 Ma). The causes and precise timing this key faunal change, as well origin eusauropods (true sauropods), have remained ambiguous mainly due to scarce dinosaurian fossil record time. sedimentary successions Cañadón Asfalto Basin central Patagonia (Argentina) document critical interval dinosaur evolution....

Herein, we report the presence of a plant paleocommunity, dominated by ferns family Osmundaceae, structurally preserved from only known Mesozoic, fossiliferous geothermal deposits, La Matilde Formation (Middle-Upper Jurassic) in Deseado Massif Southern Patagonia, Argentina. A total 13 siliceous chert blocks sampled an area approximately 250 m2, preserving monotypic assemblage Osmundaceae embedded within its original swampy substrate, are documented. Additional and fewer conifers present...

• Premise of the study: Seed cone morphology and anatomy reflect some most important changes in phylogeny evolutionary biology conifers. Reexamination enigmatic Jurassic seed Pararaucaria patagonica reveals previously unknown systematically informative characters that demonstrate affinities with Cheirolepidiaceae. This paper documents, for first time, internal cones this extinct Mesozoic conifer family, which may represent ghost lineage leading to modern Pinaceae. Methods: Morphology from La...

The seed cone Telemachus is known from several Triassic localities in Gondwana. New specimens two Antarctica provide additional information about the type species, elongatus, based on details of morphology and anatomy revealed by using a modified transfer technique compressed plants. Seed cones T. elongatus are up to 6.0 cm long characterized conspicuous, elongate bracts. A second Antarctic described here as antarcticus, segregated, shorter bract differences size. Newly recognized features...

Premise of research. Well-preserved Triassic plant fossils from Antarctica yield insights into the physiology growth under seasonal light regimes warm polar forests, a type ecosystem without any modern analogue. Among many well-known plants is enigmatic Petriellaea triangulata, dispersed seedpod structure that considered possible homologue angiosperm carpel. However, morphology and produced these seedpods have so far remained largely elusive.Methodology. Here, we describe petriellalean stems...

A new fossil conifer wood —Brachyoxylon currumilii sp. nov.— is described from the Lower—Middle Jurassic of Chubut Province (Argentina). The specimens were collected at a locality where Cañadón Asfalto Formation exposed, in vicinity Cerro Cóndor village. studied characterized by mixed pitting radial tracheid walls (predominantly uniseriate), araucarioid cross fields, low uniseriate rays and absence resin canals. use transmitted light epifluorescence microscopy together with SEM imaging...

The discovery of 16 cylindrical conifer seed cones at the Estancia Vilán locality in Late Jurassic Cañadón Calcáreo Formation Chubut Province, Patagonia, Argentina, provides anatomically preserved specimens, allowing for description a second species Pararaucaria (Cheirolepidiaceae). new species, delfueyoi, is similar general features to type patagonica, but has specifically diagnostic combination characters that include cone size, number, histology, and size. Specimens are with narrow axis...

Jurassic hot-spring chert deposits in the Deseado Massif, Patagonia, Argentina, have been known for over two decades, but associated biota has only begun to be documented recently, and thus far from a small number of localities. Here we report discovery large complex well-exposed Upper epithermal siliceous represented by organic-rich cherts preserved within geothermal system La Bajada, Santa Cruz, Argentina. The samples analyzed so contain exceptionally well-preserved, situ transported,...