Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil ...crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force). The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts.
ABSTRACT Amazonia (defined herein as the Amazon basin) is home to the greatest concentration of biodiversity on Earth, providing unique genetic resources and ecological functions that contribute to ...ecosystem services globally. The lengthy and complex evolutionary history of this region has produced heterogeneous landscapes and riverscapes at multiple scales, altered the geographic and genetic connections among populations, and impacted rates of adaptation, speciation, and extinction. In turn, ecologically diverse Amazonian biotas promoted further diversification, species coexistence, and coevolution, with biodiversity accumulating over tens of millions of years. Important events in Amazonian history included: (i) late Cretaceous and early Paleogene origin of major rainforest plant and animal groups; (ii) Eocene-Oligocene global cooling with rainforests contracting to tropical latitudes separating Atlantic coastal and Amazonian rainforests; (iii) Miocene uplift of central and northern Andes that separated Pacific coastal and Amazonian rainforests, spurred formation of mega-wetlands in the western Amazon, and contributed to the origin of the modern transcontinental Amazon River; (iv) late Neogene formation of the Panamanian Isthmus that facilitated the Great American Biotic Interchange; (v) Pleistocene climate oscillations followed by late Pleistocene-Holocene human colonization and megafaunal extinctions; and (vi) modern era of widespread anthropogenic deforestation, defaunation, and ecological transformations of regional landscapes and global climates. Amazonian conservation requires decade-scale investments into biodiversity documentation and monitoring to leverage existing scientific capacity, and strategic habitat planning to allow continuity of evolutionary and ecological processes now and into the future.
RESUMEN La Amazonía (definida como la cuenca amazónica) concentra la mayor biodiversidad de la Tierra, proporcionando recursos genéticos y funciones ecológicas únicas que contribuyen a los servicios ecosistémicos a nivel mundial. La compleja historia evolutiva de esta región produjo paisajes heterogéneos a múltiples escalas geográficas, alteró las conexiones geográficas y genéticas entre las poblaciones e influyó en las tasas de adaptación, especiación y extinción. Las biotas amazónicas, ecológicamente diversas, promovieron una mayor diversificación, coexistencia de especies y coevolución, acumulando biodiversidad a lo largo de decenas de millones de años. Acontecimientos importantes en la historia de la Amazonía incluyeron: (i) orígenes durante el Cretácico tardío y el Paleógeno temprano de los principales grupos de plantas y animales; (ii) enfriamiento global del Eoceno-Oligoceno, contrayendo los bosques a latitudes tropicales y separando los de la costa Atlántica de los amazónicos; (iii) levantamiento de los Andes centrales y del norte en el Mioceno, separando las selvas tropicales de la costa del Pacífico y de la Amazonía, estimulando la formación de megahumedales en la Amazonía occidental y contribuyendo al origen del moderno Río Amazonas transcontinental; (iv) formación del istmo de Panamá durante el Neógeno tardío, facilitando el Gran Intercambio Biótico Americano; (v) oscilaciones climáticas del Pleistoceno seguidas por la colonización humana y las extinciones de megafauna; (vi) era moderna de deforestación antropogénica generalizada, defaunación y transformaciones ecológicas de paisajes regionales y climas globales. La conservación de la Amazonía requiere inversiones por décadas en la documentación y el seguimiento de la biodiversidad para impulsar la capacidad científica existente, así como la planificación estratégica del hábitat para permitir la continuidad de los actuales y futuros procesos evolutivos y ecológicos.
(Alligatoroidea, Caimaninae) is one of the most peculiar crocodyliforms due to the skull morphology consisting of a long, wide, dorsoventrally flat rostrum with long, slender mandibular rami. Despite ...these peculiarities, the systematics, phylogeny and feeding habits of this taxon have not been properly studied. In this paper, we describe a new species of the genus,
sp. nov., from the late Miocene of the Urumaco Formation of Venezuela. The new species differs from the other
species in having a lateromedially wide, dorsoventrally high jugal bone and a circular incisive foramen, which both represent autapomorphies of the new taxon. Phylogenetically,
sp. nov. is more closely related to
and the specimen UFAC-1424 (formely attributed to
) than to
or
, whilst
is recovered once more as a monophyletic group. Furthermore, the cladistic analysis performed in this contribution offers a new phylogenetic assessment of Caimaninae, including many taxa described recently for the group. In this study, we also discuss the crocodylian diversity of the Urumaco Formation as well as how paleoenvironment may have contributed toward its evolution. In addition, we provide a discussion of the potential feeding habits of
. In this contribution,
is regarded as a taxon that likely preferred to prey on small animals. The unusual skull morphology of this group may have evolved to cover a large area with the rostrum, allowing for a more efficient prey capture, while the prey may have consisted predominantly of large amounts of small animals.
Sauropod dinosaurs compose a diversified, well known, and worldwide distributed clade, with a stereotyped body plan: deep trunk, elongated neck and tail, columnar limbs and very small skull. In ...Brazil, the group is represented by ten formally described Cretaceous species, mostly titanosaurs. This is the case of Maxakalisaurus topai, known based on an incomplete and disarticulated skeleton, unearthed from deposits of the Adamantina Formation in Minas Gerais. Here, we report a partial right dentary, including five isolated teeth, collected from the same site as the type-series of M. topai and tentatively referred to that taxon. The bone is gently curved medially, the functional teeth are set on an anterolingual position, and two replacement teeth are seen per alveoli. New morphological data gathered from that specimen was employed to conduct a comprehensive phylogenetic analysis of Titanosauria (with 42 taxa and 253 characters), based on previous studies. The Aeolosaurini clade was recovered, with Gondwanatitan and Aelosaurus as sister taxa, and Maxakalisaurus, Panamericansaurus, and Rinconsaurus forming a basal polytomy.
Human impacts outpace natural processes in the Amazon Albert, James S; Carnaval, Ana C; Flantua, Suzette G A ...
Science (American Association for the Advancement of Science),
01/2023, Volume:
379, Issue:
6630
Journal Article
Peer reviewed
Amazonian environments are being degraded by modern industrial and agricultural activities at a pace far above anything previously known, imperiling its vast biodiversity reserves and globally ...important ecosystem services. The most substantial threats come from regional deforestation, because of export market demands, and global climate change. The Amazon is currently perched to transition rapidly from a largely forested to a nonforested landscape. These changes are happening much too rapidly for Amazonian species, peoples, and ecosystems to respond adaptively. Policies to prevent the worst outcomes are known and must be enacted immediately. We now need political will and leadership to act on this information. To fail the Amazon is to fail the biosphere, and we fail to act at our peril.
Antarctic plesiosaurs are known from the Upper Cretaceous López de Bertodano and Snow Hill Island formations (Campanian to upper Maastrichtian), which crop out within the James Ross Basin region of ...the Antarctic Peninsula. Here we describe the first plesiosaur fossils from the Lachman Crags Member of the Santa Marta Formation, north-western James Ross Island. This material constitutes the stratigraphically oldest plesiosaur occurrence presently known from Antarctica, extending the occurrence of plesiosaurians in this continent back to Santonian times (86.3-83.5 Mya). Furthermore, MN 7163-V represents the first plesiosaur from this region not referable to the Elasmosauridae nor Aristonectes, indicating a greater diversity of this group of aquatic reptiles in Antarctica than previously suspected.
A new fossil gharial
Gryposuchus
species is described from the Upper Miocene Urumaco Formation, Venezuela.
Gryposuchus croizati
new species can be distinguished from other gavialoids, including
...Gryposuchus colombianus
and
Gryposuchus neogaeus
by the following combination of diagnostic characters: 1) slenderness of the parietal interfenestral bar; 2) dental formula, mainly the lesser number of maxillary teeth, with four premaxillary, 19 maxillary and 22 mandibular teeth; 3) large width of palatines between the reduced palatine fenestrae; 4) medial hemicondyle of the quadrate smaller but detached and much more posteriorly elongated than the lateral one and projected ventromedially; 5) pterygoid morphology, with two posterior vacuities. The polymorphism in the contour of the external naris in
Gryposuchus
was evaluated for taxonomic significance. The body size of
G. croizati
n. sp. was estimated in 10.15 m (9.67–10.67 m) using the dorsal skull length and the estimation of the body mass was 1,745 kg (1,280–2,379 kg) based on the braincase length. These maximal values place
G. croizati
n. sp. among the world’s largest gharials and even Crocodyliforms as a whole.
Abstract
Sarcosuchus hartii was a top predator that inhabited the fluvial and coastal areas of north-eastern Brazil during the Early Cretaceous. Several fossil remains were recovered during the late ...19th and early 20th centuries from strata that outcrop in the Recôncavo Basin in the state of Bahia. A re-analysis of this material shows that S. hartii is a valid species. The Brazilian taxon differs from the African Sarcosuchus imperator in the unique pattern of anastomosing ornamentation observed on the enamel surface. The inclusion of S. hartii in a novel phylogenetic analysis recovered it inside Tethysuchia, a large clade comprising South and North American pholidosaurids along Elosuchidae and Dyrosauridae. The evolutionary origin of Sarcosuchus is likely related to a cladogenesis event that resulted from the break-up of Gondwana.
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