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Abstract

An updated, annotated list of all tetrapods from the Adamantina, Uberaba and Marília formations (Bauru Group), which constitute some of the best studied Upper Cretaceous units in Brazil, is presented. Tetrapod diversity in the Bauru Group is remarkable, including an admixture of typically austral Gondwanan taxa (e.g., abelisaurids, notosuchians) and boreal Gondwanan forms (e.g., carcharodontosaurids). Of note is the absence of Laurasian taxa in the upper portion of the Bauru Group. With the exception of some turtles, an anuran, mesoeucrocodylians and one titanosaur, most taxa from the Bauru Group are based on fragmentary and isolated bones, and as such many specimens can be identified only to a higher taxonomic level. Fishes, turtles, anurans, mesoeucrocodylians, dinosaurs, birds and mammals from the Adamantina and Marília formations resemble the latest Late Cretaceous vertebrate faunas from southern South America, except for the absence of ornithischian dinosaurs.

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... In the literature that addresses fossil findings in the southern region of the State of Goiás, little information is available on the Upper Cretaceous fossil records of the Bauru Group, which is the only major unit of the Cretaceous Period that crops out in the south of Goiás (Candeiro et al., 2006). In western São Paulo State and the Triângulo Mineiro region, where many rocks from the Bauru Group outcrop, fossil specimens have been discovered for over 125 years (e.g., Ihering, 1911;Pacheco, 1913;Huene, 1931Huene, , 1933Candeiro et al., 2006;Martinelli & Teixeira, 2015;Candeiro & Figueirôa, 2017; see review in Brusatte et al., 2017). ...
... In the literature that addresses fossil findings in the southern region of the State of Goiás, little information is available on the Upper Cretaceous fossil records of the Bauru Group, which is the only major unit of the Cretaceous Period that crops out in the south of Goiás (Candeiro et al., 2006). In western São Paulo State and the Triângulo Mineiro region, where many rocks from the Bauru Group outcrop, fossil specimens have been discovered for over 125 years (e.g., Ihering, 1911;Pacheco, 1913;Huene, 1931Huene, , 1933Candeiro et al., 2006;Martinelli & Teixeira, 2015;Candeiro & Figueirôa, 2017; see review in Brusatte et al., 2017). However, these authors have not often been cited in later studies, which have led to misconceptions about the knowledge of the local biota. ...
... However, Bonaparte (1978) didn´t mention any dinosaur remains from the Goiás state. Based on the work of Weishampel (1993Weishampel ( , 2004, many subsequent studies (e.g., Santucci, 2002;Candeiro et al., 2004Candeiro et al., , 2006 have reported the existence of remains of "Antarctosaurus brasiliensis", sauropods, and theropods from the Bauru Group of Goiás state. ...
Article
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The southern Goiás state region of Central Brazil has an extensive and informative record of fossil biota. Particularly over the last five years, there has been a great increase in fossil finds, which has enabled a greater understanding of this region's fauna and flora during the Late Cretaceous. In this article, we provide an updated synthesis of the biota from the Cretaceous of the southern Goiás state, the record of plants, gastropods, turtles, crocodilians, titanosaurs, and theropod dinosaurs.
... Throughout the remainder of this paper, we use quotation marks whenever referring to the tooth crowns Candeiro et al. (2004Candeiro et al. ( , 2006Candeiro et al. ( , 2012a assigned to . Our analyses of these 'carcharodontosaurid' teeth were conducted after gathering new data from the specimens described by Candeiro et al. (2004Candeiro et al. ( , 2006Candeiro et al. ( , 2012a, which were housed either at the CPP or UFRJ (see Institutional abbreviations above). ...
... Throughout the remainder of this paper, we use quotation marks whenever referring to the tooth crowns Candeiro et al. (2004Candeiro et al. ( , 2006Candeiro et al. ( , 2012a assigned to . Our analyses of these 'carcharodontosaurid' teeth were conducted after gathering new data from the specimens described by Candeiro et al. (2004Candeiro et al. ( , 2006Candeiro et al. ( , 2012a, which were housed either at the CPP or UFRJ (see Institutional abbreviations above). The dental materials examined in this study were photographed using a Canon EOS Rebel T3i camera with a Canon EF-S 60 mm f /2.8 Macro USM lens in labial, lingual, apical, and basal views (additional views when needed). ...
... In the context of unambiguous dental synapomorphies of isolated theropod teeth, Hendrickx et al. (2019) summarised the following for abelisaurids: the lateral teeth have the distal denticles hooked and apically inclined from the distal margin; and three for carcharodontosaurids: 1) outline of the basal cross-section of the crown in the mesialmost tooth being subcircular, ovoid or elliptical; 2) the concave surface adjacent to the carina is absent in mesial teeth; 3) biconvex mesial denticles. In association with the comparisons detailed above, these features can help researchers differentiate between the isolated tooth crowns of abelisaurids and carcharodontosaurids. Research on theropod tooth crowns (Candeiro et al., 2004(Candeiro et al., , 2006(Candeiro et al., , 2012a has greatly contributed to our current understanding of theropod fauna in South America. This study's results further suggest that the crowns previously attributed to carcharodontosaurids actually belong to abelisaurids. ...
Article
Theropod tooth crowns are abundant in the Upper Cretaceous (post-Coniacian) continental deposits of the Bauru Group, Brazil. The distribution of anatomical crown features indicates that a variety of carnivorous dinosaurs inhabited the area at that time, which is consistent with fossil records from other parts of Gondwana. More specifically, some authors have attributed several isolated specimens to the Carcharodontosauridae; while this has important implications for palaeobiogeography and paleoecology, other scholars have argued that the clade became extinct during the Turonian. In this study, we conducted discriminant and phylogenetic analyses for 18 crowns putatively assigned to the Carcharodontosauridae. In short, the discriminant analysis suggested that the specimens should be tentatively assigned to the following groups: non-abelisauroid Ceratosauria, Abelisauridae, Neovenatoridae, Dromaeosauridae, and Pantyrannosauria. By contrast, the phylogenetic analysis indicated that all should be assigned to abelisaurid theropods, which is consistent with the theropod osteological records in both Brazil and Argentina. We recommend using a combined approach involving morphometric and phylogenetic tools when identifying isolated teeth, as this may yield more reliable identifications. We also suggest that all previous reports on the presence of post-Turonian carcharodontosaurids in the Bauru Group are invalid, which also corroborates previous work. Our results indicate that abelisaurids from the Bauru Basin were diverse in morphology and activity; that is, many were quite large and/or played important ecological roles. Findings also support the hypothesis that this taxon had a preference for semi-arid environments.
... The oldest and most recent carcharodontosaurid records come from the Kimmeridgian-Tithonian of Africa and the Turonian (Upper Cretaceous) of Asia, respectively (Brusatte et al., 2009;Canale et al., 2009;Rauhut, 2011;Novas et al., 2013). Some isolated teeth (Candeiro et al., 2004(Candeiro et al., , 2006) and a fragmentary maxilla from the Upper Cretaceous of Brazil (Azevedo et al., 2013) were putatively ascribed to a carcharodontosaurid based on dental characters, which lead some authors to suggest that this clade may have survived until the Maastrichtian (Candeiro et al., 2004(Candeiro et al., , 2006Azevedo et al., 2013). Teeth of carcharodontosaurids and abelisaurids are known to share several dental features such as a straight distal profile of the crown and pronounced undulations adjacent to the carinae . ...
... The oldest and most recent carcharodontosaurid records come from the Kimmeridgian-Tithonian of Africa and the Turonian (Upper Cretaceous) of Asia, respectively (Brusatte et al., 2009;Canale et al., 2009;Rauhut, 2011;Novas et al., 2013). Some isolated teeth (Candeiro et al., 2004(Candeiro et al., , 2006) and a fragmentary maxilla from the Upper Cretaceous of Brazil (Azevedo et al., 2013) were putatively ascribed to a carcharodontosaurid based on dental characters, which lead some authors to suggest that this clade may have survived until the Maastrichtian (Candeiro et al., 2004(Candeiro et al., , 2006Azevedo et al., 2013). Teeth of carcharodontosaurids and abelisaurids are known to share several dental features such as a straight distal profile of the crown and pronounced undulations adjacent to the carinae . ...
... Delimiting the stratigraphic distribution of carcharodontosaurids is crucial to our understanding of the evolution and ecology of the group. Materials from the Campanian-Maastrichtian have been putatively assigned to Carcharodontosauridae, but UFRJ-DG409-R is the only specimen preserving both skeletal (maxillary) and dental elements (Candeiro et al., 2004(Candeiro et al., , 2006Azevedo et al., 2013). Consequently, given the numerous characters shared between carcharodontosaurids and abelisaurids, the phylogenetic position of UFRJ-DG409-R is here investigated using the following methods: 1) a review of the osteological morphology; 2) a morphometric analysis performed on the in situ tooth (i.e., principal component, clustering and discriminant analyses), and 3) a phylogenetic analysis conducted on both the cranial and dental material. ...
Article
Carcharodontosauridae and Abelisauridae are two coexisting clades of theropod dinosaurs from the Cretaceous of Africa, South America and possibly Europe. The oldest and most recent carcharodontosaurid remains are from the Kimmeridgian-Tithonian of Africa and Turonian of South America, respectively. Recently, a fragmented maxilla bearing a single in-situ tooth (UFRJ-DG409-R) from the Maastrichtian of Brazil has been interpreted as belonging to a carcharodontosaurid. We here reassessed the phylogenetic distribution of these material using morphological, morphometric and phylogenetic analyses. If the morphology of the tooth is shared with carcharodontosaurids and abelisaurids, the morphometric analyses found the crown in the same morphospace as abelisaurids, and the phylogenetic analysis performed on a dentition-based datamatrix retrieved it among Abelisauridae. The maxilla also shares features with both groups, yet the horizontal striations on the paradental plates of UFRJ-DG409-R support abelisaurid affinities. Our data strongly suggest that these specimens belong to abelisaurid theropods, supporting the fact that carcharodontosaurids were likely extinct from Coniacian.
... The Bauru Group, which crops out in southeast and central portions of Brazil, is the largest continental unit of South American Cretaceous and yields one of the richest and most diverse fossil assemblages of the Late Cretaceous epoch. This includes a rich vertebrate fauna, including fishes, lissamphibians, turtles, squamates, theropod dinosaurs (including birds), mammals and especially sauropod dinosaurs and crocodylomorphs (see Bertini et al., 1993;Brito et al., 2006;Candeiro et al., 2006;Riff et al., 2012;Martinelli & Teixeira, 2015;França et al., 2016;Brusatte et al., 2017;Castro et al., 2018;Fachini et al., 2020;Iori et al., 2021). ...
... Its sediments were deposited in alluvial fans, alluvial plains, ephemeral lakes, and braided fluvial systems under a dry, hot climate (Salgado & Carvalho, 2008). The vertebrate fossil record of the Marília Formation is comprised by the groups typically found in the Bauru Group, including fishes, lissamphibians, squamates, turtles, crocodylomorphs and dinosaurs (e.g., Bertini et al., 1993;Santucci & Bertini, 2001;Candeiro et al., 2006;Martinelli & Teixeira, 2015). ...
Article
The Late Cretaceous continental deposits of the Bauru Group of Brazil have a rich vertebrate fossil fauna, but studies on the fossil fishes from the unit are scarce. This paper describes new occurrences of the Vidalamiinae subfamily of the bony fish group Amiidae (Halecomorphi: Amiiformes). The new occurrences are comprised by three isolated vertebral centra and three isolated teeth from the Marília and Adamantina formations, which were collected in Uberaba and Prata municipalities. The fossils described here not only expand the record of Vidalamiinae for the Bauru Group, but also clarify that the assignment of isolated teeth to this group may now be done with more certainty, which was not the case in many previous studies. Additionally, we also refer the described specimens tentatively to the Vidalamiini, which is the first assignment to this group and to the tribe level for any fish material from the Bauru Group. This study also offers an overview on the paleobiogeography of the Amiidae during the Late Cretaceous and an updated compilation of vidalamiine records during the Cretaceous, with a special focus on the freshwater records of this originally saltwater group. Finally, we also discuss the distribution of the tribes Vidalamiini and Calamopleurini during the Late Cretaceous, and the possibility that the North American and South American vidalamiines may have dispersed between the continents through a land connection. Keywords: Amiiformes, Amiidae, Vidalamiinae, Bauru Group, Late Cretaceous, biogeography. RESUMO – Os depósitos continentais do Cretáceo Superior do Grupo Bauru do Brasil possuem uma rica fauna fóssil de vertebrados, mas os estudos sobre os peixes fósseis da unidade são escassos. Este artigo descreve novas ocorrências da subfamília Vidalamiinae do grupo de peixes ósseos Amiidae (Halecomorphi: Amiiformes). As novas ocorrências são compostas por três centros vertebrais e três dentes isolados das formações Marília e Adamantina, que foram coletados nos municípios de Uberaba e Prata. Os fósseis aqui descritos não apenas ampliam o registro de Vidalamiinae para o Grupo Bauru, mas também esclarecem que a atribuição de dentes isolados a este grupo pode agora ser feita com mais certeza, o que não era o caso em muitos estudos anteriores. Adicionalmente, também remetemos os espécimes descritos provisoriamente aos Vidalamiini, que é a primeira atribuição a este grupo e ao nível de tribo para qualquer registro de peixes do Grupo Bauru. Este estudo também oferece uma visão geral da paleobiogeografia dos Amiidae durante o Cretáceo Superior e uma compilação atualizada dos registros de vidalamiine durante o Cretáceo, com foco especial nos registros de água doce desse grupo originalmente de água salgada. Por fim, também discutimos a distribuição das tribos Vidalamiini e Calamopleurini durante o Cretáceo Superior e a possibilidade de que os vidalamiines norte-americanos e sul-americanos tenham se dispersado entre os continentes por meio de uma conexão terrestre. Palavras-chave: Amiiformes, Amiidae, Vidalamiinae, Grupo Bauru, Cretáceo Superior, biogeografia.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Article
This book summarizes major aspects of the evolution of South American metatherians, including their epistemologic, phylogenetic, biogeographic, faunal, tectonic, paleoclimatic, and metabolic contexts. A brief overview of the evolution of each major South American lineage ("Ameridelphia", Sparassodonta, Didelphimorphia, Paucituberculata, Microbiotheria, and Polydolopimorphia) is provided. It is argued that due to physiological constraints, metatherian evolution closely followed the conditions imposed by global temperatures. In general terms, during the Paleocene and the early Eocene multiple radiations of metatherian lineages occurred, with many adaptive types exploiting insectivorous, frugivorous, and omnivorous adaptive zones. In turn, a mixture of generalized and specialized types, the latter mainly exploiting carnivorous and granivorous-folivorous adaptive zones, characterized the second half of the Cenozoic. In both periods, climate was the critical driver of their radiation and turnovers.
... There is a growing record of dinosaurs and other vertebrate fossils from the unequivocally latest Cretaceous (latest Santonian-Maastrichtian) aged formations of the Bauru Group . Many of these specimens are isolated teeth and vertebrae (Bertini et al. 1993, Candeiro et al. 2006a, but over the past two decades several more complete specimens, including associated partial skeletons, have been found (see below). We here focus on dinosaurs and summarize the most important aspects of their fossil record. ...
... Regardless, this fragmentary material can be assigned to a number of different groups, indicating a diverse theropod fauna. Numerous teeth have been assigned to abelisaurids and carcharodontosaurids (e.g., Kellner and Campos 2000, Candeiro 2002, 2007, Candeiro and Martinelli 2005, Candeiro et al. 2006a, b, 2012c, Candeiro and Tanke 2008, Novas et al. 2008. Furthermore, there are limited skeletal fossils of these large theropods. ...
Article
Full-text available
The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
In order to understand the timing of metatherian radiations, adaptations, and extinctions, it is important to review the variety of strongly interrelated contexts that defined them. (1) During the Cenozoic Era, global climates shifted from Greenhouse to Icehouse conditions; this major change was quite obvious by the Eocene–Oligocene boundary (ca. 33 Ma). Other large-scale changes also occurred prior and subsequent to this shift: hyperthermal events, as the Paleocene−Eocene Thermal Maximum, or cooling phases, such as that triggered by the late Miocene closing of the Panama isthmus. (2) Many elements precursor to the Cenozoic South American ecosystems were already in place by the late Mesozoic Era. By the Paleocene−early Eocene, several of the most important types (e.g., Neotropical forest, broad-leaved forest types) had developed their modern versions, as is the case of the. Grasslands seem to have been established, at least in southern South America, by the late Oligocene. (3) A recent biogeographical review supports the proposal that the southernmost tip of South America (the Andean Region) belongs to a distinct biogeographical unit, the Austral Kingdom. In turn, most of the remaining areas of South America, as well as southernmost North America and the Caribbean, comprise the Neotropical Region of the Holotropical Kingdom. South America’s Arid Diagonal is the great biogeographic divide between the Neotropical Region and the Andean Region. The distribution of this arid-semiarid belt, originally placed in much of southwestern Gondwana, closely matches the distribution of the Subtropical Seasonal Dry climatic belt since early Mesozoic times. (4) Reinforcing this climatic divide of the continent, paleogeographic reconstructions of South America suggest that the continent was split into northern and southern portions by means of epeiric seas due to marine transgressions. In southernmost South America, the paleogeography resulting from marine transgressions led to a very complex, almost archipelagic continental configuration. (5) At least six successive phases can be recognized in the evolution of Mesozoic–Cenozoic South American mammals: Early Gondwanian, Late Gondwanian, Early South American, Late South American, Interamerican, and Hypoamerican.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
The Metatheria include not only marsupials but all therians more related to Marsupialia than to the Eutheria. Marsupialia is considered as a metatherian crown group including all extant marsupials, their common ancestor and all of their descendants. “Ameridelphia” is not a natural group. Australidelphia includes the Microbiotheria and all Australasian marsupials. Several authors also argue that the Polydolopimorphia are Australidelphians as well. Relationships of Sparassodonta with other Metatheria are a matter of discussion. To several authors, they are more closely related to South American and Australian groups than to basal North American and/or Asian metatherians. Our concept of Didelphimorphia includes the Peradectoidea (Peradectidae and Caroloameghiniidae) and the Didelphoidea (Didelphidae and Sparassocynidae). In several analyses, the Paucituberculata appear as more closely related to the Australidelphia than to the Didelphimorphia. The relationships of the Microbiotheria within the Australidelphia have been subject of much discussion. They have been considered either as sister-taxa of all other Australidelphia, at the base of Diprotodontia, as a sister-taxon of Dasyuromorpha, as a sister-taxon of Phalangeriformes + Diprotodontia, or even related with part of the former.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
South American living metatherians are relatively inconspicuous and comprise ca. 10 % of the region’s mammal species richness. Most of them are small-sized (<150 g), with long tails and grasping hands and feet, and resemble one another in their general appearance. Individuals are solitary, nocturnal or crepuscular, and most of them are arboreal or scansorial. Two orders are exclusive of South America (Microbiotheria and Paucituberculata), while a third (Didelphimorphia) ranges from Patagonia (Argentina) to the border between USA and Canada. The ecology, physiology, and reproductive traits of living South American marsupials have been poorly studied. This chapter describes several aspects of their natural history and how they influence their recent distribution, as they probably did so throughout the Cenozoic. Physiological constraints include variable energetic costs for regulating metabolic processes, due to low rates of metabolism, the possibility to enter torpor/hibernation, and the storage of different types of fat tissues available for those varied processes. Reproduction, which can be characterized by a short gestation period and long, energy-demanding, breeding period, shows specific differences in strategies (e.g., semelparity, partial semelparity, iteroparity) and their main traits (e.g., litters per year and litter size, teat number). South American marsupials make a complete use of the habitat available to them and have a broad, generally opportunistic and omnivorous diet. These adaptations, combined with a general small size, small energy expenditure on foraging and other daily activities, limit their distribution. Despite these constraints, South American marsupials seem to thrive in environments where competition with other animals might be strong (e.g., tropical and subtropical climates), or where a few small mammals can survive (e.g., temperate and temperate-cold climates) due to several environmental limitations.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
Diversity, dietary, and body mass analyses suggest that the early Eocene represents the major radiation event in South America metatherian evolutionary history. During this period, representatives of all orders typical of the Paleogene reached their greatest diversity (i.e., “basal ameridelphians”; Polydolopimorphia Polydolopiformes, and Bonapartheriiformes Bonapartherioidea); frugivory was the dominant trophic niche. By the middle late Eocene occurs a functional and taxonomic turnover. Among the Polydolopimorphia, frugivore types declined and were replaced by larger-sized frugivores/folivores (Polydolopiformes) and smaller-sized granivores (Bonapartheriiformes). The Sparassodonta showed a diversity increase and occupied the large-sized hypercarnivore niches. The Eocene–Oligocene boundary constitutes another extinction and turnover event marked by the disappearance of “basal ameridelphians”, the Polydolopiformes and Bonapartheriiformes Bonapartherioidea. Lineages that survive into the Deseadan are the Sparassodonta, Paucituberculata, Microbiotheria, and Bonapartheriiformes Argyrolagoidea. Dominant trophic types were those of carnivores and granivores. Environmental factors probably modeled the Paleogene metatherian faunal dynamics in South America. Mean annual temperatures (MAT) and precipitations seem the main factors modeling the taxonomic and trophic diversity, respectively. The adaptive radiation of the early Eocene seems associated with the maximum thermal event of the late Paleocene-early Eocene. The turnover event of the late Eocene seems associated with a sharp drop in the rainfall regime. The extinction and turnover event of the Eocene–Oligocene boundary also seem associated with a strong drop in ambient temperatures. The diversity in evolution of Paleogene metatherians shows a pattern similar to that of living marsupials at the latitudinal level. For a given mean temperature, the number of species in extinct associations is very close to that of the living ones.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
Full-text available
The early Paleocene diversity of metatherians in Tiupampan faunas of South America and the pre-Tiupampan Paleocene polydolopimorphian Cocatherium speak in favor of an earliest Paleocene or Late Cretaceous dispersal of metatherians from North America. No Late Cretaceous metatherian or eutherian mammals have been recovered to date in South America, but the late Campanian to Maastrichtian hadrosaurine dinosaurs in Argentina, as well as the late Maastrichtian of the Antarctic Peninsula, is evidence of a biotic connection to North America. Placental ‘condylarths’ in the Tiupampan may have been related to, and dispersed southward relative to, Puercan taxa in North America and perhaps reflect a somewhat later event in comparison to metatherians. Other than hadrosaurine dinosaurs, Late Cretaceous vertebrates of South America are basically Gondwanan in affinities and reflect (and survived) the pre-106 Ma connection between South America, Africa, and Antarctica. The potential for a Late Cretaceous dispersal of metatherians would be compatible with a continued dispersal to Australia at that time, also supported by plate tectonic relationships, notwithstanding the basically endemic coeval Australian dinosaur fauna, and recognizing the essential absence of a Late Maastrichtian land vertebrate record there. An early Paleocene connection between at least Antarctica and South America is documented by the presence of a monotreme in the Peligran fauna of Patagonia. This, coupled with the fact that post-Peligran mammal faunas in South America and the Antarctic Peninsula (from at least 52 Ma in that location) are composed of derived metatherian as well as placental mammals, suggests that dispersal of metatherians to Australia had been achieved prior to the Eocene. Such timing is compatible with the still plesiomorphic level of Australian metatherians from the early Eocene Tingamarra fauna of Australia, the marine sundering of the Tasman Gate at about 50 Ma and the development of a continuously marine southern coastline of Australia from about 45 Ma effectively foreclosed overland mammal and other vertebrate dispersal to Australia thereafter.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Chapter
We summarize the configuration of plates, geographical barriers, and possible dispersal events during the Late Cretaceous–Cenozoic between North and South America, the Caribbean, Antarctica, and Australia. The arrival of metatherians in South America was a Late Cretaceous event, and probably a Maastrichtian one. There are few doubts that the first metatherians in this continent arrived from North America. We suggest that not only eutherian mammals but also metatherians may have reached South America from the north in a series of successive dispersal waifs. This FABI (First American Biotic Interchange) may have replicated the successive waif dispersal mood of the late Cenozoic GABI (Great American Biotic Interchange). The initial radiation of basal South American metatherian lineages (“Ameridelphia”) may have already occurred by Late Campanian-Maastrichtian times. We also suggest that a cooling pulse happening by the Latest Cretaceous (Late Maastrichtian, ca. 68–67 Ma) may have been involved in the origin of the Australidelphia, as part of the southern (Austral Kingdom) Nothofagus biota. Four out of six faunal phases were involved in the evolution of South American metatherians: (1) Early South American (Late Cretaceous to the Late Eocene), Late South American (Early Oligocene to late Miocene), Interamerican (Plio–Pleistocene), and Hypoamerican (Holocene). The first of these phases involved the arrival and expansion of many lineages and adaptive types. The global cooling by the Eocene–Oligocene Boundary implied the extinction of many (mostly tropical) lineages, as well as the diversification of several specialized ones. The third of these faunal phases transpired during a time lapse of ecological imbalance and global cooling, while the last phase saw already much impoverished metatherian associations throughout the continent.
... Prior to about 106 Ma (late Albian) when South America and Africa finally broke apart (Lawver et al. 2013), Gondwana was still essentially intact, and land vertebrate dispersal was basically possible throughout South America, Africa, Madagascar, India, Australia, and Antarctica. The taxa in the Brazilian assemblages were basically endemic to South America (Candeiro et al. 2004(Candeiro et al. , 2006(Candeiro et al. , 2008de la Fuente et al. 2007;Candeiro and Rich 2010), with a diversity of fish, lepidosaurian frogs, aniloid snakes, podocnemid turtles, mesoeucrocodylians, spinosaurid, carcharodontosaurid, abelisaurid, and titanosaurid 'dinosaurs,'enatiornithine birds, and a mammal of uncertain allocation. Overall, the assemblage is typically of Gondwanan affinity and is closely related to coeval biota in Madagascar, India, and continental Africa (Candeiro et al. 2004;Candeiro and Rich 2010 Fig. 3.3), correlated to about 69 Ma. ...
... suggested that the radiation of these endemic mammals was a Late Cretaceous (Cenomanian-Maastrichtian) event (their "Late Gondwanan Phase"), and that it was triggered by the global warming that developed since the Cenomanian. Bertini et al. (1993) and Candeiro et al. (2006) noted the presence of a potentially therian mammal from the Turonian-Santonian (ca 85 Ma) Adamantina Formation of Brazil (1, Fig. 3.3), but this awaits further verification. Tiu. ...
Book
With more than 100 species, living South American marsupials (Mammalia, Metatheria) give only a glimpse of the much higher taxonomic and ecological diversity acquired by metatherians throughout the Cenozoic Era. The term Metatheria designs a taxon within Mammalia that includes not only Marsupialia but also all therian mammals more related to Marsupialia than to Eutheria. Several features (e.g., epipubic ones) formerly considered as diagnostic of Metatheria are now regarded either a primitive condition or not present in all members of this group. Other derived features, such as the presence of a shelf-like, inflected angular process in the lower jaw, are consistently present in all metatherians. A brief characterization of all major South American, Cenozoic metatherian lineages is given: “basal ameridelphians,” Sparassodonta, Didelphimorphia, Paucituberculata, Microbiotheria, and Polydolopimorphia (the latter including Polydolopiformes and Bonapartheriiformes). Three periods can be distinguished in the history of our knowledge of Cenezoic South American Metatheria: the first one (1878–1930) is intimately linked to Florentino Ameghino, Argentina’s most notable paleontologist; much of our knowledge on extinct metatherians from South America was elaborated by him. The second period (1930–1977) occurred under the influence of George Gaylord Simpson’s ideas. Bryan Patterson and Rosendo Pascual also had an important imprint in South America’s Mammalian Paleontology. The third period (1977-present) is currently evolving under new phylogenetic, taxonomic, and paleobiogeographic paradigms; influences are multiple and major reviews of specific lineages are currently in the making. A final note on the incompleteness of Cenozoic South America’s fossil record is made: only the mid to high latitudes, basically in the Southern Cone, are moderately well-sampled in their terrestrial fossil record.
... Titanosauria currently represents the most species-rich dinosaur clade in the Brazilian Cretaceous (Bittencourt & Langer, 2011;Ghilardi et al., 2016;Carvalho et al., 2017;Bandeira et al., 2018), with numerous records coming from the Serra da Galga Formation (Bauru Group, Bauru Basin) in the surroundings of Uberaba, Minas Gerais State (Candeiro et al., 2006;. Field work carried-out in that area, from the late 1940's to the 1960's, by the Brazilian paleontologist Llewellyn Ivor Price, were especially productive (Campos & Kellner, 1999), followed by systemic excavations conducted by the Centro de Pesquisas Paleontológicas Llewellyn Ivor Price (CPPLIP) and Museu dos Dinossauros since the beginning of the 1990s. ...
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The description of new titanosaur specimens unearthed from deposits of the Serra da Galga Formation (Bauru Group, Late Cretaceous) at the BR-262 site, near Peirópolis (Uberaba, Minas Gerais State, Brazil), sheds light on the taxonomy of two taxa previously known from the same area and geological unit: Baurutitan britoi and Trigonosaurus pricei. A comparative revision indicates that T. pricei represents a junior synonym of Ba. britoi, and that the BR-262 specimens belong to that latter species. The information provided by the new specimens also revealed that the paratype of T. pricei (MCT 1719-R), a caudal vertebral series, actually represents a new taxon, named here as Caieiria allocaudata gen. et sp. nov.
... The Bauru Group ( Figure 1) is a vertebrate-rich Late Cretaceous lithostratigraphic unit that crops-out in south-central Brazil (Menegazzo et al. 2016;Batezelli 2017), which is famous for its extensive record of crocodyliforms (Carvalho et al. 2010;Godoy et al. 2014;Martinelli and Teixeira 2015). However, this diversity is currently represented only by notosuchians (Mannion et al. 2015;Pol and Leardi 2015), a group of predominantly terrestrial, small-to mediumsized crocodyliforms, which are not directly linked to the extant crocodylians and exhibited a wide range of morphologies and ecologies (Candeiro et al. 2006;Turner 2006;Carvalho et al. 2010;Godoy et al. 2014;Godoy et al. 2020;Nascimento 2014;Pol et al. 2014;Iori and Arruda-Campos 2016;Marsola et al. 2016;Melstrom et al. 2019;Montefeltro 2019;Wilberg et al. 2019;Stubbs et al. 2021). One of the most significant fossil-bearing areas of the Bauru Group is the Monte Alto municipality, which has already yielded five formally named notosuchians: Caipirasuchus montealtensis, Caipirasuchus paulistanus, Morrinhosuchus luziae, Montealtosuchus arrudacamposi, and Barreirosuchus franciscoi (Carvalho et al. 2007;Iori and Carvalho 2009;Montefeltro et al. 2011;Iori and Garcia 2012;Iori et al. 2013;. ...
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Most crocodyliforms of the Bauru Group were found in rocks of the Adamantina Formation, whereas the younger Marília Formation is almost devoid of such fossils. Here, we provide a detailed comparative description of MPMA 02–0005/87, a large skull roof found in Marília Formation deposits of the Monte Alto area, assigning it to a new crocodyliform. Despite its fragmentary nature and puzzling suit of characters, the new taxon possesses enough characters to reject its placement within Notosuchia, which is so far the only crocodyliform clade known from the Bauru Group. We tested its phylogenetic position with twodata matrices, both of which recovered the new taxon within Neosuchia and Eusuchia. Although the material does not preserve any eusuchian synapomorphy, a neosuchian affinity is supported by: anterior extension of the meatal chamber covered by the squamosal; constricted flange of the posterior process of the postorbital; poorly developed posterolateral process of squamosal. Finally, the large size estimated for the specimen, ranging from 2.98 to 5.88 metres, coupled with its possible neosuchian affinity, suggests a possible semiaquatic behaviour, an ecology rarely explored by the predominantly terrestrial crocodyliforms of the Bauru Group. http://www.zoobank.org/urn:lsid:zoobank.org:pub:3C7C9499-FFE3-4D5A-A90B-DE2E3572EF16 http://www.zoobank.org/urn:lsid:zoobank.org:pub:98FFC142-674F-464D-BCFD-721C608A2635
... The rocks of the Serra da Galga Formation at this site are predominantly composed of sandstones and sandy conglomerates, interpreted as river channels and floodplain deposits; also, paleosols are commonly found (Soares et al., 2018;Martinelli et al., 2019). Among the described taxa unearthed from P1P, there are records of charophytes, several groups of invertebrates, fish, anurans, lizards, turtles, crocodyliforms, and dinosaurs (e.g., Dias-Brito et al., 2001;Candeiro et al., 2006;Novas et al., 2008;Gaffney et al., 2011;Martinelli et al., 2013;Martinelli and Teixeira, 2015). ...
Article
Notosuchia is a highly diverse group of crocodyliforms that peaked during the Cretaceous period. Their taxonomic abundance and morphological disparity in the Upper Cretaceous Bauru Group (Bauru Basin, Brazil) is remarkable, with over 20 species reported. The stable carbon and oxygen isotope composition of notosuchian bioapatite from two sites (i.e., the Ponto 1 do Price and Fazenda Três Antas) in west Minas Gerais State was analyzed to evaluate differences in feeding habits among the taxa found in both localities. Possible environmental stressors are examined, in parallel to sedimentological, paleopedological, and paleontological studies, which indicate a semi-arid to arid climate for the Bauru Group. Multiple tissues of notosuchian crocodyliforms were included in our study, as well as a testudines carapace fragment, lepisosteiform fish teeth and scales, and host rocks. The mineral textures, X-ray diffraction and stable isotope data support preservation of tooth enamel and scale ganoin bioapatite. The δ¹³C results point to different feeding habits between two terrestrial, carnivore notosuchians, namely a terrestrial source diet for Uberabasuchus terrificus and an aquatic source diet for Campinasuchus dinizi. The δ¹⁸Ow for the crocodyliform data was calculated and compared to other Upper Cretaceous sites. Values support dry conditions during the formation of the bioapatite for the Fazenda Três Antas site and point to the Hateg Basin in Romania, yet likely younger, as a good paleoclimatic analogue.
... The Brazilian abelisaurid record is composed mainly by Late Cretaceous taxa, such as the brachyrostran Pycnonemosaurus nevesi from the Campanian to Maastrichtian Parecis Group (Kellner and Campos, 2002;Bittencourt and Langer, 2011), and Thanos simonattoi, from the Santonian São Jos e do Rio Preto Formation (Delcourt and Iori, 2018), both from the Bauru Group. Other isolated and fragmentary abelisaurid fossils are also common in the Upper Cretaceous rocks from Brazil (Bertini, 1996;Bittencourt and Kellner, 2002;Kellner and Campos, 2002;Candeiro et al., 2006;Novas et al., 2008;Brusatte et al., 2017;Grillo and Delcourt, 2017), with isolated abelisaurid teeth being found in strata as old as the Cenomanian of Alcântara Formation (Sales et al., 2018). The oldest record of Abelisauridae in Brazil is the well-preserved Spectrovenator ragei from the BarremianeAptian Quiric o Formation (Zaher et al., 2020). ...
Article
Several studies have used isolated crocodyliform and theropod teeth as an important tool for taxonomic identification, as they can often be the only record of some taxa. The objective of this paper is the description and identification of the isolated crocodyliform and theropod teeth in order to clarify which taxa inhabited the western portion of the Potiguar Basin during mid-Cretaceous. The material consists of six tooth crowns from Açu Formation (Albian–Cenomanian), Potiguar Basin, northeastern Brazil. The crowns were identified by a set of qualitative (morphological comparisons and cladistics) and quantitative analyses. UFRJ-DG 659Rd was identified through morphological comparison as a peirosaurid crocodyliform due to its true ziphodont condition, enamel with an irregular texture, and faint lingual fluting. Five of the tooth crowns were identified as abelisaurid theropods based on the results of the cladistic analysis and morphological comparison, with the quantitative analysis supporting this result only for two of the five teeth. This result represents the first report of peirosaurids and abelisaurids in Potiguar Basin, and possibly one of the oldest abelisaurid records in Brazil.
... Casal et al. (2007) described a second Aeolosaurus species, Ae. colhuehuapensis, unearthed from the Campanian-Maastrichtian Bajo Barreal Formation, central Patagonia. Furthermore, in the last 20 years or so, there were several reports of Aeolosaurus sp. in the Upper Late Cretaceous rocks of southeastern and central Brazil, usually based upon incomplete and poorly preserved material (e.g., Bertini et al. 1999a;Bertini et al. 1999bBertini et al. , 2000Candeiro 2006Candeiro , 2010Candeiro et al. 2006;Lopes and Buchmann 2008;Santucci and Bertini 2017). The referral of these specimens to Aeolosaurus was questioned by Martinelli et al. (2011), who instead considered them all as indeterminate Aeolosaurini. ...
Article
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Aeolosaurus is a late Cretaceous Titanosaur genus with two species discovered in Argentina and one in Brazil. Although the allocation of the Argentinean Aeolosaurus seems unequivocal, that is not the case for the Brazilian species Aeolosaurus maximus since several authors questioned its positioning into this genus, based on both anatomical and phylogenetic data. The revision of the diagnosis of Ae. maximus, with the proposition of a new autapomorphy, corroborates the anatomical uniqueness and our phylogenetic analysis stresses that the relation of Ae. maximus to the Argentinean Aeolosaurus is uncertain. Based upon that, we propose a new genus, Arrudatitan, to accommodate the Brazilian taxon.
... Most of their record in South America is restricted to Argentine Patagonia (e.g., Neuquén, Golfo San Jorge and Austral basins) and the Bauru Basin of SW Brazil [7][8][9] (Fig. 1a). Some studies have attempted to establish paleobiogeographic links between these regions 10,11 , although there are remarkable faunistic differences between Patagonian and Brazilian titanosaurians [12][13][14][15] . Similarly, other contemporaneous tetrapods, such as pleurodiran turtles and notosuchian mesoeucrocodylians, also show heterogeneous distributions 16,17 . ...
Article
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South American titanosaurians have been central to the study of the evolution of Cretaceous sauropod dinosaurs. Despite their remarkable diversity, the fragmentary condition of several taxa and the scarcity of records outside Patagonia and southwestern Brazil have hindered the study of continental-scale paleobiogeographic relationships. We describe two new Late Cretaceous titanosaurians from Quebrada de Santo Domingo (La Rioja, Argentina), which help to fill a gap between these main areas of the continent. Our phylogenetic analysis recovers both new species, and several Brazilian taxa, within Rinconsauria. The data suggest that, towards the end of the Cretaceous, this clade spread throughout southern South America. At the same locality, we discovered numerous accumulations of titanosaurian eggs, likely related to the new taxa. With eggs distributed in three levels along three kilometres, the new site is one of the largest ever found and provides further evidence of nesting site philopatry among Titanosauria.
... The Bauru Basin covers 370,000 km 2 of geographical area (Fernandes and Coimbra, 2000;Fernandes and Ribeiro, 2015), and from this geological unit, a plethora of fossilized organisms are recovered, which provide essential information related to the evolution of Gondwana biodiversity during the Upper Cretaceous (Santucci and Bertini, 2001;Candeiro et al., 2006Candeiro et al., , 2018Candeiro and Rich, 2010;Rogério et al., 2013;Fernandes and Ribeiro, 2015;Brusatte et al., 2017;Bandeira et al., 2018). This geological basin had its depositional dynamics in a great depression in the southeastern part of the South American Platform (Fernandes and Coimbra, 1996;Fernandes and Basilici, 2009; see also Fernandes and Ribeiro, 2015;and, Basilici et al., 2019 for the history of the Bauru Basin evolution), where the sedimentary deposition occurred in an interval of at least 40 Ma, above the magmatic rocks of Serra Geral Formation (Paula e Silva et al., 2009). ...
Article
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The Tartaruguito outcrop (Pirapozinho municipality, Presidente Prudente Formation, Bauru Basin) has been considered a Fossil-Lagerstätte due to its exceptional fossil quality and large number of fossils recovered. Despite its historical and paleontological importance, a geochemical composition study of the fossils from this site and their sedimentary matrixes has never been performed. Here, we have analyzed fossil turtle shell fragments and their respective sedimentary matrixes collected at Tartaruguito through Powder X-Ray Diffraction and Infrared Spectroscopy techniques, to determine their geochemical composition and obtain clues regarding the fossil dia-genesis processes. The analyses showed that the fossil remains of the side-necked turtle Bauruemys elegans from the Tartaruguito locality are mainly composed of calcite (CaCO 3) and hydroxyapatite partially substituted by fluorine (Ca 10 (PO 4) 6 (OH) 2-x F x). The sedimentary matrixes are mostly composed of quartz (SiO 2) and calcite, with secondary amounts of feldspar. The presence of calcite on both, fossil and rocky matrix, might indicate that the fossil diagenesis process that occurred at the Tartaruguito locality was permineralization by calcite, especially considering the absence of quartz on the bones of the fossil specimens. Furthermore, the presence of a fluor-hy-droxyapatite solid-solution might be a plausible explanation for the quality of fossils recovered in Tartaruguito, due to the better stability of fluorapatite when compared to hydroxyapatite.
... The rich fossil record of the Bauru Group has yielded a rich assemblage of vertebrate and invertebrate ichnofossils, continental mollusks, arthropods, freshwater fishes, amphibians, squamates, theropod and sauropod dinosaurs, birds and a diverse fauna of Crocodyliformes (Bertini et al. 1993;Dias-Brito et al. 2001;Arruda et al. 2005;Candeiro et al. 2006). The Crocodyliformes from Bauru Basin comprise at least five distinct groups of Mesoeucrocodylia: the notosuchids, sphagesaurids, baurusuchids, trematochampsids and peirosaurids . ...
Article
We describe a new species of Peirosauridae (Crocodyliformes, Mesoeucrocodylia), Montealtosuchus arrudacamposi gen. nov. et sp. nov., from the Late Cretaceous (Turonian-Santonian) strata of the Bauru Basin, Brazil. Montealtosuchus was found at the outskirts of Monte Alto County in reddish sandstones of the Adamantina Formation. This specimen is exquisitely preserved with skull, mandible, postcranial and exoskeletal elements in articulation that provides critical information of the anatomy of this group. The occurrence of Peirosauridae in the Adamantina Formation (Turonian-Santonian) widens the chronostratigraphic range of this Mesoeucrocodylia taxon in Brazil. Recent analysis suggests that the Peirosauridae is restricted to the Late Cretaceous deposits of South America.
... The fossil content of the Bauru Basin is mainly concentrated in the Bauru Group, which records a plethora of vertebrates, including dinosaurs, crocodilians, turtles, lizards, anurans, birds, and mammals [28][29][30] . As a whole, the fauna of the Bauru Group indicates a Coniacian to Maastrichtian age 27 , as corroborated by a recent radioisotopic dating 31 . ...
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Noasaurines form an enigmatic group of small-bodied predatory theropod dinosaurs known from the Late Cretaceous of Gondwana. They are relatively rare, with notable records in Argentina and Madagascar, and possible remains reported for Brazil, India, and continental Africa. In south-central Brazil, the deposits of the Bauru Basin have yielded a rich tetrapod fauna, which is concentrated in the Bauru Group. The mainly aeolian deposits of the Caiuá Group, on the contrary, bear a scarce fossil record composed only of lizards, turtles, and pterosaurs. Here, we describe the first dinosaur of the Caiuá Group, which also represents the best-preserved theropod of the entire Bauru Basin known to date. The recovered skeletal parts (vertebrae, girdles, limbs, and scarce cranial elements) show that the new taxon was just over 1 m long, with a unique anatomy among theropods. The shafts of its metatarsals II and IV are very lateromedially compressed, as are the blade-like ungual phalanges of the respective digits. This implies that the new taxon could have been functionally monodactyl, with a main central weight-bearing digit, flanked by neighbouring elements positioned very close to digit III or even held free of the ground. Such anatomical adaptation is formerly unrecorded among archosaurs, but has been previously inferred from footprints of the same stratigraphic unit that yielded the new dinosaur. A phylogenetic analysis nests the new taxon within the Noasaurinae clade, which is unresolved because of the multiple alternative positions that Noasaurus leali can acquire in the optimal trees. The exclusion of the latter form results in positioning the new dinosaur as the sister-taxon of the Argentinean Velocisaurus unicus.
... The Bauru Group is considered one of the most important geological units from Brazil due the occurrence of many vertebrate fossils (Azevedo and Simbras 2009;Candeiro et al. 2008;Candeiro et al. 2006a). Despite this context, virtually no work has focused in applying a taphonomic approach to the vertebrate fossils found in it (e.g., Araújo-Júnior and Marinho 2013). ...
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PurposeThe Bauru Group is worldwide known due to its high diversity of archosaurs, especially that of Crocodyliformes. Recently, it has been suggested that the Crocodyliformes, especially the Baurusuchidae, were the top predators of the Bauru Group, based on their anatomical convergence with theropods and the dearth of those last ones in the fossil record of this geological group. Methods Here, we erect the hypothesis that assumption is taphonomically biased. For this purpose, we made a literature survey on all the published specimens of Theropoda, Baurusuchidae and Titanosauria from all geological units from the Bauru Group. Also, we gathered data from the available literature, and we classified each fossil find under a taphonomic class proposed on this work. ResultsWe show that those groups have different degrees of bone representativeness and different qualities of preservation pattern. Also, we suggest that baurusuchids lived close to or in the abundant flood plains, which explains the good preservation of their remains. Theropods and titanosaurs did not live in association with such environments and the quality of their preservation has thus been negatively affected. Conclusions We support the idea that the Baurusuchidae played an important role in the food chain of the ecological niches of the Late Cretaceous Bauru Group, but the possible biases in their fossil record relative to Theropoda do not support the conclusion that baurusuchids outcompeted theropods. Rather, this taphonomic bias must be tackled first, which previous studies have not regarded.
... The Marilia Formation is a sedimentary succession located in the Bauru Basin, an intraplate basin of southeastern Brazil, which records the Upper Cretaceous series. The paleoenvironmental interpretations of this unit were mainly based in their abundant fossil record, which has been the subject of many studies in recent decades, especially based on dinosaurs, crocodiles, fishes, mollusks, and turtles ( Bertini et al., 1993;Candeiro et al., 2006Candeiro et al., , 2008Carvalho et al., 2007;Marinho et al., 2013;Marsola et al., 2016). However, the studies are still scarce in the case of trace fossils, with just some works referred to the Bauru Basin ( Fernandes & Carvalho, 2006;Carvalho et al., 2009;Cardoso et al., 2013;Nascimento et al., 2017a;Mineiro et al., 2017). ...
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The Marilia Formation (Bauru Group, Bauru Basin) is an important record of the Upper Cretaceous in Brazil, and hosts an important fossil content. However, works regarding continental ichnology in this unit are still scarce. In order to improve this knowledge, the present work describes the occurrence of Camborygma litonomos in paleosols developed from floodplain deposits of the Marilia Formation in the Minas Gerais State. This trace fossil is associated with the activity of freshwater crayfishes, digging the soil looking for protection and to avoid the carapace dryness. Crayfish body fossils have not yet been described in deposits of the Bauru Group, thus, the trace fossil here recorded is the exclusive evidence of this organism, which is of great importance to the knowledge of the invertebrates paleodiversity of the Marilia Formation during the Late Cretaceous.
... Most Brazilian theropod nominal species and the best-known specimens come from the Lower Cretaceous Santana Formation in the northeast of the country (i.e., Irritator challengeri, Angaturama limai, Santanaraptor placidus, Mirischia asymmetrica; Kellner and Campos, 1996;Martill et al., 1996;Kellner, 1999;Sues et al., 2002;Naish et al., 2004;Carvalho et al., 2015). However, in recent years a more diverse Late Cretaceous theropod assemblage has been described in other geological units of the country, but still known from mostly fragmentary specimens, including abelisaurids (e.g., Pycnomemosaurus nevesi; Kellner and Campos, 2002;Delcourt, 2017;Delcourt and Grillo, 2017), spinosaurids (e.g., Oxalaia quilombensis; Kellner et al., 2011), probable carcharodontosaurids (Vilas Bôas et al., 1999;Candeiro et al., 2004Candeiro et al., , 2006, megaraptorans (M endez et al., 2012;Martinelli et al., 2013;Sales et al., 2017), and possibly noasaurids (Lindoso et al., 2012) and maniraptorans (Elias et al., 2004;Bittencourt and Langer, 2011). As part of the Early Cretaceous theropod record, Frey and Martill (1995) described a partial sacrum articulated to two caudal vertebrae and a partial right ilium (SMNS 58023) from the Albian beds of the Santana Formation. ...
Article
A specimen composed of a partial sacrum articulated to two anterior caudal vertebrae and an ilium (SMNS 58023) from the Lower Cretaceous (Albian) Santana Formation of Brazil was originally described as an oviraptorosaur, but it is here re-interpreted as the oldest megaraptoran of South America. The phylogenetic relationships of SMNS 58023 were tested quantitatively for the first time including it in the two most comprehensive phylogenetic data sets focused on non-maniraptoran theropods –including megaraptorans. The Brazilian specimen was consistently found as a megaraptoran in both analyses because of the presence of sacral centra longer than tall, absence of a median transverse constriction of sacral centra, and the morphology and position of sacral pleurocoels. SMNS 58023 sheds light on a region of the body that is poorly known in megaraptorans and pulls back the temporal range of the clade in South America. This re-interpretation reinforces the absence of oviraptorosaurs in Gondwana.
... For example, Romano and Azevedo ( 2006 ) have suggested that Bauruemys is the sister taxa of Podocnemididae, while Gaffney et al. ( 2011 ) included this species in the podocnemidid clade Bauruemydinae as the sister group of the remaining Podocnemididae. Candeiro et al. 2006 ) (Fig. 5.5c, e ). Comments: After a detailed description of the DNPM specimen (a partial carapace and plastron) was used by Staesche ( 1937 ) to erect Podocnemis brasiliensis , concluded that this material belongs to two different specimens. ...
Book
The extended continental South American turtle record (Norian to Lujanian) allows us to follow the evolution of this reptile clade from its origins. Several significant stem turtle taxa such as: Palaeochersis talampayensis and Condorchelys antiqua provide information on the first steps of turtle evolution. Others such as: Chubutemys copelloi or Patagoniaemys gasparinae provide clues to the origin of the bizarre horned tortoises of the clade Meiolaniidae. The panpleurodiran species such as Notoemys laticentralis or Notoemys zapatocaensis shed light on the origin of modern pleurodiran turtles. This book explores aquatic and terrestrial cryptodiran turtles, South Gondwana pleurodiran turtles, North Gondwana pleurodiran turtles; Meiolaniforms and early differentiation of Mesozoic turtles. © Springer International Publishing Switzerland 2014. All rights reserved.
... For example, Romano and Azevedo ( 2006 ) have suggested that Bauruemys is the sister taxa of Podocnemididae, while Gaffney et al. ( 2011 ) included this species in the podocnemidid clade Bauruemydinae as the sister group of the remaining Podocnemididae. Candeiro et al. 2006 ) (Fig. 5.5c, e ). Comments: After a detailed description of the DNPM specimen (a partial carapace and plastron) was used by Staesche ( 1937 ) to erect Podocnemis brasiliensis , concluded that this material belongs to two different specimens. ...
Chapter
Panpleurodiran clade Platychelyidae extends from the Oxfordian to the Valanginian of Cuba, South America, and Europe. The oldest member of Platychelyidae was recovered from the Oxfordian of Cuba. The Upper Jurassic record is represented in Europe by only one Kimmeridgian–Tithonian species and in South America by two species. A shallow marine connection between the Western Tethys and Eastern Pacific through central Pangaea was present since the beginning of the Jurassic and acted as a corridor for numerous pelagic reptile groups as the panpleurodiran turtles. Stem turtles (i.e., stem Testudines) from the Late Triassic until the Middle Jurassic have had a Pangaean distribution, and they are known from all continents except Australia and Antarctica. Two species are recognized in South America: the Late Triassic Palaeochersis talampayensis and the Middle Jurassic Condorchelys antiqua.
... A cursorial barauchisaurid, Pabwehshi pakistanensis, has also been reported from the Upper Cretaceous Pab Formation of Pakistan (Wilson et al., 2001). A nearly complete and quite diverse crocodyliform fossil record is known from the Late Cretaceous of Brazil and Argentina (Ortega et al., 2000; Martinelli, 2003; Candeiro et al., 2006; Fiorelli and Calvo, 2008; Marinho and Carvalho, 2009), Africa (Sereno and Larsson, 2009), Madagascar (Buckley and Brochu, 1999; Buckley et al., 2000; Turner, 2006; Turner and Buckley, 2008) and Australia (Salisbury et al., 2006). A quite diverse assemblage of crocodylomorphs known from the Campanian Maverano Formation of Madagascar is traditionally considered to be Gondwanan in origin. ...
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The biogeographic affinities of the Indian plate during its northward movement are at present intensely debated, especially in the context of strong geophysical evidence pointing towards an isolated Indian Subcontinent during the Late Cretaceous (~90 to ~65 Ma). It is difficult to conceive of the possibility of a direct land route for the exchange of vertebrates (mainly of large size, e.g., dinosaurs) between India and its surrounding landmasses, particularly at ~65 Ma. In this context, the terrestrial vertebrate fauna from the Late Cretaceous Deccan volcano-associated sedimentary deposits (infra-and intertrappean sediments) of India has been the focus of study by paleontologists and paleobiogeographers alike for many years. Fragmentary remains of a number of vertebrate taxa have been described from the Late Cretaceous (Maastrichtian) of India, including frogs, lizards, turtles, snakes, dinosaurs and mammals, and this fauna bafflingly points to an admixture of Gondwanan, Laurasian and endemic elements. Phylogenetic data in a paleogeographic context have raised the possibility of biotic exchanges between India and Madagascar during the Late Cretaceous. Although the size of the animal should have been a limiting factor (favoring the small animals), during such a trans-oceanic exchange (as postulated earlier for the exchange of fauna between India and Asia via the Kohistan Dras volcanic arc system), crossing over vast marine barriers was not propitious, except for the large-sized vertebrates (particularly dinosaurs). So, a direct terrestrial route (particularly in the north of India) is a lesser possibility, and the distribution of these giant vertebrates should be viewed in terms of a " Pan-Gondwanan " model. Nevertheless, the paucity of complete fossil specimens from the Cretaceous interval of erstwhile Gondwanaland, including the Indian Subcontinent, is the first obstacle that needs to be overcome for further inferences.
... The Upper Cretaceous fossil records from western São Paulo State, southeastern Brazil, have been studied since the beginning of the twentieth century through expeditions conducted by geologists and palaeontologists of the Companhia Nacional de Petr oleo and the Departamento Nacional de Produção Mineral (see historical context in Ilhering, 1911;von Huene, 1931). This area presents one of the most diversified continental Upper Cretaceous vertebrate assemblages from Central Brazil, represented by the remains of fishes, frogs, lizards, turtles, crocodilians, dinosaurs (including birds), and a mammal (e.g., Gayet and Brito, 1989;Bertini et al., 1993;Candeiro et al., 2006;Candeiro and Rich, 2010 and references herein). ...
... The Upper Cretaceous fossil records from western São Paulo State, southeastern Brazil, have been studied since the beginning of the twentieth century through expeditions conducted by geologists and palaeontologists of the Companhia Nacional de Petr oleo and the Departamento Nacional de Produção Mineral (see historical context in Ilhering, 1911;von Huene, 1931). This area presents one of the most diversified continental Upper Cretaceous vertebrate assemblages from Central Brazil, represented by the remains of fishes, frogs, lizards, turtles, crocodilians, dinosaurs (including birds), and a mammal (e.g., Gayet and Brito, 1989;Bertini et al., 1993;Candeiro et al., 2006;Candeiro and Rich, 2010 and references herein). ...
... Regarding Cretaceous deposits, the recovered specimens indicate the presence of abelisauroids, carcharodontosaurids, spinosaurids, megaraptorans, tyrannosauroids, compsognathids, non-avian deinonychosaurs and enantiornithes (Bertini et al., 1993;Kellner and Campos, 2000;Bittencourt and Langer, 2011;Kellner and Campos, 2012;M endez et al., 2012;Martinelli et al., 2013;Carvalho et al., 2015). By far, most Brazilian theropod material comes from Bauru Group and is predominantly referred to Abelisauroidea (Bertini et al., 1993;Bertini, 1996;Candeiro et al., 2006Candeiro et al., , 2012Novas et al., 2008;Azevedo et al., 2013;Machado et al., 2013;M endez et al., 2014;Tavares et al., 2014). Almost all specimens have been sporadically collected some decades ago and have not been analyzed so far. ...
... Ichnofossils, eggs, gastroliths and coprolites are also known from the group (e.g. Grellet-Tinner & Zaher, 2007;Fernandes et al., 2008) Since the Bauru Group is an important paleontological site (Azevedo, 2009;Candeiro et al., 2008;Candeiro et al., 2006), this work presents a taphonomic approach to vertebrate fossils found in the group. ...
Article
The Bauru Basin covers an area of about 370.000 km2, occurring in São Paulo, Paraná, Mato Grosso, Mato Grosso do Sul, Minas Gerais and Goiás states in Brazil, and also in the northeast of Paraguay. These upper Cretaceous sequence correspond to a semi-arid to arid climate and is divided in two groups, Bauru and Caiuá. The first one has the major record of fossils, being the focus of the taphonomic study. Field trips to Marília and Monte Alto municipalities (São Paulo State) and also to Uberaba city (Minas Gerais State) were made to check the depositional context and collect fossiliferous material. Vertebrate collections were visited, as the Museu de Paleontologia from Marília and Monte Alto (SP), Museu de Paleontologia da Universidade de São Paulo, as well as Museu dos Dinossauros, Centro de Pesquisas Paleontológicas Llewellyn Ivor Price from Peirópolis (MG). Four biostratinomic classes related to articulated/disarticulated fossils were identified in Vale do Rio Peixe, Uberaba, Marília, São José do Rio Preto and Presidente Prudente formations. Class I represents articulated and almost complete specimens, corresponding mainly to turtles and crocodiles. Class II comprises partially articulated specimens of skull and jaw fossils, or sequences of vertebrae. Classes I and II were recorded in Vale do Rio do Peixe, Marília (Serra da Galga Member) and Presidente Prudente formations. Class III is represented by isolated bones, and Class IV by fragmented bones. These two last classes appear in all units of the basin. For diagenetic analysis, 19 thin sections were made showing that, in general, the bone structure is well preserved, with spatic calcite filling the bone and the presence of the original phosphatic material. Marília Formation, on Echaporã Member, is the most different unit of the basin, being more carbonatic. The study of thin sections, considering the osseous structure and the biostratinomic analysis, match with the paleoenvironmental contextualization.
... For example, Romano and Azevedo ( 2006 ) have suggested that Bauruemys is the sister taxa of Podocnemididae, while Gaffney et al. ( 2011 ) included this species in the podocnemidid clade Bauruemydinae as the sister group of the remaining Podocnemididae. Candeiro et al. 2006 ) (Fig. 5.5c, e ). Comments: After a detailed description of the DNPM specimen (a partial carapace and plastron) was used by Staesche ( 1937 ) to erect Podocnemis brasiliensis , concluded that this material belongs to two different specimens. ...
Chapter
Tortoises are terrestrial turtles grouped in the clade Testudinidae. This clade represents 18 % of the living turtle diversity and is the most widespread group of nonmarine turtles, distributed across all nonpolar continents except Australia. The fossil history of the clade dates back to the Palaeocene of Asia. The South American forms are represented by the genus Chelonoidis, which includes 4 extant and 4 extinct named species. The invasion of tortoises in South American is a contentious subject, and two continental sources have been proposed (Central America and Africa).
... In the eastern portion of the Triângulo Mineiro, mainly in the vicinity of the Peiróplis locality, near Uberaba, fossiliferous outcrops have been known since the 1920s, but only since 1947 have these started to be prospected, with the efforts of Llewellyn Ivor Price (Candeiro, 2005). The paleovertebrate fossils found there include anurans, chelonians, squamata, crocodylians and dinosaurs (Candeiro et al., 2006). The most conspicuous dinosaur fossils are of titanosaurid sauropods (Bertini et al., 1993;Kellner & Campos, 2000;Almeida et al., 2004;Marinho & Candeiro, 2005;Kellner et al., 2005;Campos et al., 2005 ...
... For example, Romano and Azevedo ( 2006 ) have suggested that Bauruemys is the sister taxa of Podocnemididae, while Gaffney et al. ( 2011 ) included this species in the podocnemidid clade Bauruemydinae as the sister group of the remaining Podocnemididae. Candeiro et al. 2006 ) (Fig. 5.5c, e ). Comments: After a detailed description of the DNPM specimen (a partial carapace and plastron) was used by Staesche ( 1937 ) to erect Podocnemis brasiliensis , concluded that this material belongs to two different specimens. ...
Chapter
Meiolaniformes include the bizarre group of extinct Cenozoic turtles bearing cranial horns and frills (clade Meiolaniidae) and several species located in its stem. Most meiolaniforms are from Gondwana (Australia and South America), with the exception of two Eurasiatic taxa (Kallokibotion bajazidi and Mongolochelys efremovi). Meiolaniformes were originated in the present-day South America and they are known from the Lower Cretaceous until the Holocene. The oldest fossils within the clade (Chubutemys copelloi and Otwayemys cunicularius) indicate a minimum age of origin in the Aptian–Albian (Lower Cretaceous).
... For example, Romano and Azevedo ( 2006 ) have suggested that Bauruemys is the sister taxa of Podocnemididae, while Gaffney et al. ( 2011 ) included this species in the podocnemidid clade Bauruemydinae as the sister group of the remaining Podocnemididae. Candeiro et al. 2006 ) (Fig. 5.5c, e ). Comments: After a detailed description of the DNPM specimen (a partial carapace and plastron) was used by Staesche ( 1937 ) to erect Podocnemis brasiliensis , concluded that this material belongs to two different specimens. ...
Chapter
Extant and extinct species of chelid turtles are limited in distribution to South America and Australasia with an extensive fossil record in South America (Early Cretaceous–Recent) and more scarce in Australasia (Early Cretaceous, Eocene, Oligocene, and Miocene to Recent). Taking into account their specific richness, chelids are one of the most diverse South American turtle clades. This fact and the above-mentioned disjointed distribution, the early fossil record, and the phylogenetic data suggest an early differentiation from Pelomedusoides at least in the Early Cretaceous in South Gondwanan landmasses.
... Pascual et al. (2000) claimed the occurrence of Docodonta; however, subsequent papers place the taxon in question (i.e., Reigitherium Bonaparte, 1990) among the Dryolestoidea (Rougier et al., 2011). The South American Mesozoic taxa come from the Callovian-Oxfordian Cañadón Asfalto Formation, the Barremian-Aptian La Amarga Formation, the Cenomanian Candeleros Formation, the Turonian-Santonian Adamantina Formation and several (Allen, Anacleto, El Molino, La Colonia, and Los Alamitos) formations of the Late Cretaceous Campanian-Maastrichtian (Bonaparte, 1986(Bonaparte, , 1987(Bonaparte, , 1990(Bonaparte, , 1992(Bonaparte, , 1994(Bonaparte, , 2002Goin et al., 1986;Bertini et al., 1993;Pascual et al., 2000;Gayet et al., 2001;Rauhut et al., 2002;Candeiro et al., 2006;Rougier et al., 2007aRougier et al., ,b, 2009aRougier et al., ,b, 2010Rougier et al., , 2011Bonaparte and Migale, 2010). Some lineages are likely endemic from Gondwana (Australosphenida, Gondwanatheria), while others have a broader distribution. ...
Article
We report on a new dryolestoid (Mammalia, Dryolestoidea, Meridiolestida) from the Los Bastos Formation (Coniacian), Neuquen Province, Patagonia, Argentina, consisting of an edentulous left dentary (MCF-PVPH 412). The alveoli preserved suggest the presence of three incisors, one double-rooted canine, and six double-rooted postcanines (probably three premolars and three molars). Based on comparisons with previously known dentaries and isolated teeth, MCF-PVPH 412 would have been about the same size as Reigitherium Bonaparte. Among Dryolestoidea, MCF-PVPH 412 is assigned to Meridiolestida because there were probably three molars, the roots of the posterior molars are anteroposteriorly compressed, and there is no Meckelian groove. In addition, the penultimate lower premolar would be the largest in the tooth series, which is also true in other meridiolestidans. The position of the mandibular foramen, the probable presence of three premolars, and the outline of the posteroventral part of the jaw suggest affinities with the Mesungulatoidea (e.g., Coloniatherium Rougier, Forasiepi, Hill and Novaceck; Peligrotherium Bonaparte, Van Valen and Kramarz; and Reigitherium). The Coniacian specimen represents the oldest Mesungulatoidea and fills the gap in the record between the oldest South American dryolestoid (i.e., Cenomanian) and the better known Campanian-Maastrichtian taxa. The discovery of MCF-PVPH 412 in the Coniacian of Patagonia is consistent with the dryolestoid diversification during the Late Cretaceous that makes them the most abundant mammals during that period in South America.
Article
Abelisaurids are medium–large-sized theropod dinosaurs that were predominant in the carnivorous fauna during the Late Cretaceous of Gondwana. These predators are abundant in the Cretaceous fossil strata of Patagonia, which yield the best record for this group. In the Late Cretaceous, abelisaurids appear in almost all regions of Gondwana and in all stages, except for the Coniacian, in which they are globally unknown. Here we describe a new abelisaurid, Elemgasem nubilus gen. et sp. nov., from the Portezuelo Formation (Turonian–Coniacian), Patagonia, Argentina. The palaeohistology of the appendicular bones of Elemgasem shows that the holotype was a subadult individual, but had achieved sexual maturity. This taxon is based on several axial and appendicular elements, and is diagnosed by the presence of a marked pattern of rugosity on the lateral surface of the fibula and a dorsoventrally deep lateral wall of the calcaneum. Moreover, the posterior caudal vertebrae have a morphology slightly different from any other abelisaurid. Elemgasem nubilus is recovered as an unstable taxon within Brachyrostra, given that it was recovered as sister taxon of Furileusauria or in several positions within this clade. Despite the problematic phylogenetic relationships of Elemgasem nubilus, it is important because it is the first abelisaurid from the Turonian–Coniacian interval and it increases the diversity of this theropod family at a time of marked turnover in the tetrapod fauna of South America, global climate change, and mass extinction events recorded worldwide in the marine realm.
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Titanosaurian sauropods are known to exhibit remarkable body size disparity, with some taxa famed for nearing the zenith of terrestrial vertebrate body size. Here, we describe a new titanosaurian – Ibirania parva gen. et sp. nov. – from the Upper Cretaceous (Santonian– Campanian) São José do Rio Preto Formation of Bauru Basin, in which represents one of the smallest sauropods known to date. The new taxon is diagnosed by seven autapomorphies and had an estimated body length of 5.7 m. Histological and μCT scan analyses showed that this new taxon is represented by skeletally mature individuals, which had attained somatic maturity prior to death. Phylogenetic analyses recovered the new taxon deeply nested within Saltasaurinae, a clade previously known by small-sized forms. Ibirania parva gen. et sp. nov. brings new information indicating that the body size reduction in some titanosaurians could be driven by recurrent ecophysiographical settings, present in South America prior to the diversity peak attained by the group during the Campanian–Maastrichtian.
Chapter
The South American fossil record of Mesozoic mammals and close relatives is one of the best for Gondwana. Early mammals and relatives are found in about a dozen localities in Argentina, Brazil, Bolivia, Chile, and presumably Peru, including a broad sample of non-mammaliaform cynodonts of the Triassic age. Mesozoic mammals span from the latest Early Jurassic to the latest Cretaceous, furthermore some of those archaic lineages unexpectedly survived the end of the Cretaceous period, remaining as minority elements in the Paleocene–Miocene faunal associations. The fossiliferous localities bearing these fossils are presented in this chapter, highlighting the geological setting, age, and their faunal associations.
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Abelisauridae is a broad dinosaur family of Theropoda that includes large extinct carnivores as well as extant birds. The distribution is mostly in the southern hemisphere, although some specimens are found in Europe. The phylogenetic relationships of the abelisaurids have been improved, but there is still some disagreement regarding the inclusion of some groups in the family, which deserve attention. The body plan of the abelisaurids is conservative among the group, but they have a large cranial disparity. They also tend to develop cranial structures such as horns, thick skull bones, and cornified covering. The variety of cranial soft tissues associated with skeletal features suggests that abelisaurids may have had low-stress headbutting behavior. The Brazilian record is still scarce, and there are only two known species from different geological units. Even so, it is possible to observe that the abelisaurid diversity in Brazil was large.
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A new peirosaurid crocodyliform from the Upper Cretaceous (Santonian) of South America, Barrosasuchus neuquenianus gen. et sp. nov. is here described. Barrosasuchus is distinguished by a combination of features that include: presence of a foramen at the mid-point of the dorsal surface of the mandibular symphysis; quadratojugal dorsally broad, extensively contacting the postorbital articulation; absence of ventral exposure of splenials along mandibular rami, posterior to the symphysis; mid to posterior teeth with roots and crowns highly compressed laterally; presence of longitudinal depressions on palatal surface of maxillae; and anterior dentary alveoli strongly procumbent. The holotype specimen of Barrosasuchus neuquenianus, MCF-PVPH-413 is represented by an almost complete skull and most of the articulated postcranial skeleton. Thus, Barrosasuchus is currently the most complete peirosaurid taxon known from Patagonia, and represents a key element for future reviews of the phylogeny of the group. Peirosauridae represents a successful clade in Gondwana, and particularly in Patagonia, with at least six distinct genera currently recorded.
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The diversity of extant squamates in South America is in deep contrast to the extremely scarce knowledge of squamates from that continent during the Mesozoic, particularly regarding terrestrial lizards. Here we provide a review of the most recent advances in knowledge of Cretaceous lizards from South America, focusing on named species (all from Brazil). These forms included scansorial, as well as cursorial taxa, likely displaying facultative bipedalism. In the case of Crato Formation specimens, only juvenile specimens were reported so far, which raises questions about the role of taphonomic biases and community structure. Iguanians (acrodontans and non-acrodontans), as well as scincomorphs, are known since the Aptian/Albian. All iguanians had a broad Late Cretaceous distribution which, along with findings in the Early-Middle Jurassic of India, suggest an early radiation of the group before the final break up of Laurasia and Gondwana. Gondwanan regions may have played a fundamental role in the initial history of acrodontan iguanians despite the fact that, at least in South America, only non-acrodontans and scincomorphs are known to have passed through the Cretaceous-Paleogene boundary.
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Friedrich von Huene’s important scientific research on tetrapod fossils from Central Brazil has received little attention, even though it represents a significant contribution to early studies of vertebrate paleontology in the country including the first discoveries of dinosaur fossils in Brazil. von Huene described five reptile taxa in two papers published in important German scientific journals and used these specimens to make paleogeographic inferences regarding the Cretaceous of the Southern Hemisphere. von Huene warrants recognition as the first specialist to describe in detail the fossil reptile fauna of Central Brazil, which was made possible only by his network of contacts with important and influential naturalists of the cities of Rio de Janeiro and São Paulo.
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The Chubut Group, central Patagonia, Argentina, is characterized by a lacustrine and fluvial-lacustrine system with variable participation of volcanic ash. This group includes the Bajo Barreal Formation (Cenomanian-Turonian) and a recently nested new lithostratigraphic unit, the Lago Colhue Huapi Formation (Coniacian-Maastrichtian). The Lago Colhue Huapi Formation overlies the Bajo Barreal Formation. These sedimentary units preserve a rich and diverse vertebrate fossil record including, among others, representatives of Crocodylomorpha, Testudines, Pterosauria and abundant Dinosauria. Nevertheless, the stratigraphic position of several of its taxa has been historically controversial. The unclear stratigraphic provenance of these taxa difficults the correct interpretation of the relationships with other Patagonian and South American basins. In this context, we present a detailed stratigraphic study to clarify the position of the vertebrate fossils of both Late Cretaceous formations. We also discuss the implications of this faunistic arrangement in terms of vertebrate evolution and paleobiogeography. Finally, this study broadens our knowledge on the fossil fauna of these units and therefore the vertebrate assemblages of central Patagonia.
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We summarize here the Late Cretaceous vertebrate record of the Triângulo Mineiro (western portion of the Minas Gerais State, southeastern Brazil). All the specimens come from the Bauru Group (Bauru Basin) from the Adamantina (Campanian), Uberaba (Campanian) and Marília (Maastrichtian) formations. Vertebrate-bearing sites are distributed throughout the Triângulo Mineiro, but the Uberaba County has the largest diversity of Late Cretaceous vertebrate from the Bauru Group, mainly concentrated in the Serra da Galga Member of the Marília Formation. So far, the following taxa have been recognized in the Triângulo Mineiro, from the Adamantina Formation: Amiiformes indet., cf. Atractosteus sp. (Lepisosteiformes), Mesoeucrocodylia indet., Sphagesaurus sp. (Sphagesauridae), Campinasuchus dinizi and Pissarrachampsa sera (Baurusuchidae), Maxakalisaurus topai (Titanosauria), Titanosauria indet., and Abelisauridae indet.; from the Uberaba Formation: Titanosauria indet. and Megaraptora indet.; from the Marília Formation: Ceratodus sp. (Dipnoi), Vidalamiine indet. (Amiiformes), Lepisosteiformes indet., Siluriformes indet., Characiformes indet., Perciformes indet., Baurubatrachus pricei and Uberabatrachus carvalhoi (Neobatrachia), Cambaremys langertoni, Peiropemys mezzalirai and Pricemys caiera (Podocnemididae) and Podocnemididae indet., Pristiguana brasiliensis (Iguania), Itasuchus jesuinoi (Trematochampsidae), Labidiosuchus amicum (Notosuchia), Peirosaurus torminni and Uberabasuchus terrificus (Peirosauridae), Trigonosaurus pricei, Baurutitan brittoi, Uberabatitan ribeiroi, Aeolosaurini indet. (Titanosauria), Abelisauroidea indet., Abelisauridae indet., cf. Carcharodontosauridae indet., Maniraptora indet., Avialae indet., and Enantiornithes indet. The Triângulo Mineiro region has a great paleontological potential which will generate future results amplifying the diversity and knowledge of the Late Cretaceous vertebrates of Brazil. © 2015, Instituto Geologico y Minero de Espana. All rights reserved.
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Diverse crocodyliforms have been discovered in recent years in Cretaceous rocks on southern landmasses formerly composing Gondwana. We report here on six species from the Sahara with an array of trophic adaptations that significantly deepen our current understanding of African crocodyliform diversity during the Cretaceous period. We describe two of these species (Anatosuchus minor, Araripesuchus wegeneri) from nearly complete skulls and partial articulated skeletons from the Lower Cretaceous Elrhaz Formation (Aptian-Albian) of Niger. The remaining four species (Araripesuchus rattoides sp. n., Kaprosuchus saharicus gen. n. sp. n., Laganosuchus thaumastos gen. n. sp. n., Laganosuchus maghrebensis gen. n. sp. n.) come from contemporaneous Upper Cretaceous formations (Cenomanian) in Niger and Morocco.
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