TL;DR: An insight is provided into the Meso- and Cenozoic record of Amazonia that was characterized by fluvial and long-lived lake systems and a highly diverse flora and fauna, whilst fossil pollen and spores form relics of ancestral swamps and rainforests.
Abstract: The book focuses on geological history as the critical factor in determining the present biodiversity and landscapes of Amazonia. The different driving mechanisms for landscape evolution are explored by reviewing the history of the Amazonian Craton, the associated sedimentary basins, and the role of mountain uplift and climate change. This book provdes an insight into the Meso- and Cenozoic record of Amazonia that was characterized by fluvial and long-lived lake systems and a highly diverse flora and fauna. This fauna includes giants such as the ca. 12 m long caiman Purussaurus, but also a varied fish fauna and fragile molluscs, whilst fossil pollen and spores form relics of ancestral swamps and rainforests. Finally, a review the molecular datasets of the modern Amazonian rainforest and aquatic ecosystem, discussing the possible relations between the origin of Amazonian species diversity and the palaeogeographic, palaeoclimatic and palaeoenvironmental evolution of northern South America. The multidisciplinary approach in evaluating the history of Amazonia has resulted in a comprehensive volume that provides novel insights into the evolution of this region.
TL;DR: A diversity peak in sympatric occurrence of at least seven species is shown, based on detailed stratigraphic sequence sampling and correlation, involving four geological formations from the middle Miocene to the Pliocene, and on the discovery of two new species and a new occurrence.
Abstract: Northern South America and South East Asia are today’s hotspots of crocodylian diversity with up to six (mainly alligatorid) and four (mainly crocodylid) living species respectively, of which usually no more than two or three occur sympatrically. In contrast, during the late Miocene, 14 species existed in South America. Here we show a diversity peak in sympatric occurrence of at least seven species, based on detailed stratigraphic sequence sampling and correlation, involving four geological formations from the middle Miocene to the Pliocene, and on the discovery of two new species and a new occurrence. This degree of crocodylian sympatry is unique in the world and shows that at least several members of Alligatoroidea and Gavialoidea coexisted. By the Pliocene, all these species became extinct, and their extinction was probably related to hydrographic changes linked to the Andean uplift. The extant fauna is first recorded with the oldest Crocodylus species from South America.
TL;DR: A cladistic analysis of 32 alligatorid and three outgroup taxa resulted in 1210 equally most parsimonious cladograms, all of which suggest that Culebrasuchus mesoamericanus, gen. et sp.
Abstract: Despite the fact that fossil crocodylians have been recovered from the Panama Canal Zone starting with initial excavations in 1912, detailed studies have been lacking. Recent excavations of the canal have resulted in new discoveries of many vertebrate fossils, including the first known Miocene crocodylian skulls from Central America. These fossil skulls from the early-middle Miocene represent two new taxa with distinct morphology that is shared with extinct and extant caimans (Caimaninae). A cladistic analysis of 32 alligatorid and three outgroup taxa, scored for 75 characters, resulted in 1210 equally most parsimonious cladograms, all of which suggest that Culebrasuchus mesoamericanus, gen. et sp. nov., is the sister taxon to all previously known Caimaninae. Additionally, the analysis suggests that Centenariosuchus gilmorei, gen. et sp. nov., is the sister taxon to a caimanine clade that includes Purussaurus from the Miocene of South America. In fact, teeth very similar to those of Purussaurus h...
TL;DR: A phylogenetic analysis of 164 characters in 68 ingroup crocodile taxa supported the association of P. neivensis and P. mirandai with five synapomorphies and confirmed the sister‐group relationship of the genus with the Nettosuchidae.
Abstract: Synopsis Fossil Crocodylia are taxonomically diverse in South America, particularly in the upper Miocene Urumaco Formation (Venezuela). Among them is the giant alligatoroid Purussaurus, previously known from the upper Miocene Solimoes Formation in Brasil (P. brasiliensis) and the middle Miocene of La Venta in Colombia (P. neivensis). New specimens of Crocodylia from the Urumaco Formation are described and a new species, Purussaurus mirandai, erected. This is characterised by a large, elongate and extremely flat skull, a very large narial opening comprising almost 60% of rostral length and a large incisive foramen that extends anteriorly between the fossae for the first mandibulary teeth. Purussaurus mirandai sp. nov. was the largest predator in the swampy environments and represented the top trophic level in the Urumaco assemblage. A phylogenetic analysis of 164 characters in 68 ingroup crocodile taxa supported the association of P. neivensis and P. mirandai with five synapomorphies and confirmed the sist...
TL;DR: The fossil crocodylomorph fauna of the Cenozoic of South America is very rich and diverse as discussed by the authors, and a comprehensive review of the South American Crocodylic fauna is necessary.