The first Caipirasuchus (Mesoeucrocodylia, Notosuchia) from the Late Cretaceous of Minas Gerais, Brazil: new insights on sphagesaurid anatomy and taxonomy.

Field work conducted by the staff of the Centro de Pesquisas Paleontológicas Llewellyn Ivor Price of the Universidade Federal do Triângulo Mineiro since 2009 at Campina Verde municipality (MG) have resulted in the discovery of a diverse vertebrate fauna from the Adamantina Formation (Bauru Basin). The baurusuchid Campinasuchus dinizi was described in 2011 from Fazenda Três Antas site and after that, preliminary descriptions of a partial crocodyliform egg, abelisaurid teeth, and fish remains have been done. Recently, the fossil sample has been considerably increased including the discovery of several, partially articulated fish remains referred to Lepisosteiformes and an almost complete and articulated skeleton referred to a new species of Caipirasuchus (Notosuchia, Sphagesauridae), which is the main subject of this contribution. At present, this genus was restricted to the Adamantina Formation cropping out in São Paulo state, with the species Caipirasuchus montealtensis, Caipirasuchus paulistanus, and Caipirasuchus stenognathus. The new material represents the holotype of a new species, Caipirasuchus mineirus n. sp., diferenciated from the previously ones due to the following traits: last two maxillary teeth located posterior to anterior edge of infraorbital fenestra, elongated lateroventral maxillo-jugal suture-about ½ the anteroposterior maxillar length-and contact between posterior crest of quadrate and posterior end of squamosal forming an almost 90° flaring roof of the squamosal, among others. C. mineirus was found in the same outcrop than Campinasuchus but stratigraphically the former occurs in the lower portion of the section with no unambiguous data supporting the coexistance of both taxa.

Revised morphology of Pycnonemosaurus nevesi Kellner & Campos, 2002 (Theropoda: Abelisauridae) and its phylogenetic relationships.

Abelisaurid theropods were most abundant in the Gondwana during the Cretaceous Period. Pycnonemosaurus nevesi Kellner & Campos, 2002 was the first abelisaurid dinosaur described from the Bauru Group (Brazil, Upper Cretaceous). Nevertheless, its initial description was based on the comparison of a restricted number of remains with other abelisaurids. In this paper, I present a new description of the morphology of Pycnonemosaurus nevesi, including three new caudal transverse processes and a discussion of several new characteristics based on perspectives derived from recently described abelisauroids. Pycnonemosaurus nevesi differs from other abelisaurids based on the following features: a pubis with a small rounded foot and a ventrally-bowed anterior distal end; posterior caudal vertebrae with a hook-shaped transverse process that has an anterodistal expansion that is short and bowed; a strong and massive tibia with a well-developed lateral malleolus that is ventrally expanded. The unfused sutures represent signs of skeletal immaturity, but the specific ontogenetic stage is still uncertain. The current phylogenetic analysis suggests strongly relationship within Pycnonemosaurus and the most-derived abelisaurids (e.g Carnotaurus and Aucasaurus).

Intra-specific variation and allometry of the skull of Late Cretaceous side-necked turtle Bauruemys elegans (Pleurodira, Podocnemididae) and how to deal with morphometric data in fossil vertebrates.

BACKGROUND: Previous quantitative studies on Bauruemys elegans (Suárez, 1969) shell variation, as well as the taphonomic interpretation of its type locality, have suggested that all specimens collected in this locality may have belonged to the same population. We rely on this hypothesis in a morphometric study of the skull. Also, we tentatively assessed the eating preference habits differentiation that might be explained as due to ontogenetic changes. METHODS: We carried out an ANOVA testing 29 linear measurements from 21 skulls of B. elegans taken by using a caliper and through images, using the ImageJ software. First, a Principal Components Analysis (PCA) was performed with 27 measurements (excluding total length and width characters; =raw data) in order to visualize the scatter plots based on the form variance only. Then, a second PCA was carried out using ratios of length and width of each original measurement to assess shape variation among individuals. Finally, original measurements were log-transformed to describe allometries over ontogeny. RESULTS: No statistical differences were found between caliper and ImageJ measurements. The first three PCs of the PCA with raw data comprised 70.2% of the variance. PC1 was related to size variation and all others related to shape variation. Two specimens plotted outside the 95% ellipse in PC1∼PC2 axes. The first three PCs of the PCA with ratios comprised 64% of the variance. When considering PC1∼PC2, all specimens plotted inside the 95% ellipse. In allometric analysis, five measurements were positively allometric, 19 were negatively allometric and three represented enantiometric allometry. Many bones of the posterior and the lateral emarginations lengthen due to increasing size, while jugal and the quadratojugal decrease in width. DISCUSSION: ImageJ is useful in replacing caliper since there was no statistical differences. Yet iterative imputation is more appropriate to deal with missing data in PCA. Some specimens show small differences in form and shape. Form differences were interpreted as occuring due to ontogeny, whereas shape differences are related to feeding changes during growth. Moreover, all outlier specimens are crushed and/or distorted, thus the form/shape differences may be partially due to taphonomy. The allometric lengthening of the parietal, quadrate, squamosal, maxilla, associated with the narrowing of jugal and quadratojugal may be related to changes in feeding habit between different stages of development. This change in shape might represent a progressive skull stretching and enlargement of posterior and lateral emargination during ontogeny, and consequently, the increment of the feeding-apparatus musculature. Smaller individuals may have fed on softer diet, whereas larger ones probably have had a harder diet, as seen in some living species of Podocnemis. We conclude that the skull variation might be related to differences in feeding habits over ontogeny in B. elegans.

Postcranial anatomy of Pissarrachampsa sera (Crocodyliformes, Baurusuchidae) from the Late Cretaceous of Brazil: insights on lifestyle and phylogenetic significance.

The postcranial anatomy of Crocodyliformes has historically been neglected, as most descriptions are based solely on skulls. Yet, the significance of the postcranium in crocodyliforms evolution is reflected in the great lifestyle diversity exhibited by the group, with members ranging from terrestrial animals to semi-aquatic and fully marine forms. Recently, studies have emphasized the importance of the postcranium. Following this trend, here we present a detailed description of the postcranial elements of Pissarrachampsa sera (Mesoeucrocodylia, Baurusuchidae), from the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). The preserved elements include dorsal vertebrae, partial forelimb, pelvic girdle, and hindlimbs. Comparisons with the postcranial anatomy of baurusuchids and other crocodyliforms, together with body-size and mass estimates, lead to a better understanding of the paleobiology of Pissarrachampsa sera, including its terrestrial lifestyle and its role as a top predator. Furthermore, the complete absence of osteoderms in P. sera, a condition previously known only in marine crocodyliforms, suggests osteoderms very likely played a minor role in locomotion of baurusuchids, unlike other groups of terrestrial crocodyliforms. Finally, a phylogenetic analysis including the newly recognized postcranial features was carried out, and exploratory analyses were performed to investigate the influence of both cranial and postcranial characters in the phylogeny of Crocodyliformes. Our results suggest that crocodyliform relationships are mainly determined by cranial characters. However, this seems to be a consequence of the great number of missing entries in the data set with only postcranial characters and not of the lack of potential (or synapomorphies) for this kind of data to reflect the evolutionary history of Crocodyliformes.

New lower jaw and teeth referred to Maxakalisaurus topai (Titanosauria: Aeolosaurini) and their implications for the phylogeny of titanosaurid sauropods.

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.

A new squamate lizard from the Upper Cretaceous Adamantina Formation (Bauru Group), São Paulo State, Brazil

The record of non-mosasaur squamates (Reptilia, Squamata) is sparse in the Cretaceus fossil record of Brazil and include six putative reports, three from the Aptian-Albian of the Araripe Basin (Tijubina pontei Bonfim-Júnior and Marques, Olindalacerta brasiliensis Evans and Yabumoto, and a lizard indet.) and three from the Upper Cretaceous of the Bauru Group (Pristiguana brasiliensis Estes and Price, Anilioidae gen. et sp. indet., and Squamata gen. et sp. indet.). In this contribution, a new genus and species of lizard, Brasiliguana prudentis gen. et sp. nov., is described based on an isolated left maxilla with teeth. The material was discovered in an outcrop of the Upper Cretaceous Adamantina Formation (Bauru Group) located in the proximity of Presidente Prudente Municipality, São Paulo State, Brazil. The new taxon is considered a basal non-Priscagamidae+Acrodonta iguanian based on the presence of a weakly inclined anterior margin of the maxillary nasal process and maxillary tooth shape and tooth implantation similar to that of iguanians rather than of other lizard groups (e.g. teiids). This finding significantly increases the squamate lizard diversity of South America, which is still poorly understood and sparsely represented in the fossil record.

Os achados de escamados (Reptilia, Squamata) são escassos no Cretáceo do Brasil, incluindo cinco registros pontuais, dois do Aptiano-Albiano da Bacia do Araripe (Tijubina pontei Bonfim-Júnior e Marques e Olindalacerta brasiliensis Evans e Yabumoto), e três do Cretáceo Superior do Grupo Bauru (Pristiguana brasiliensis Estes and Price, Anilioidae gen. et sp. indet., Squamata gen. et sp. indet.). Nesta contribuição apresentamos um novo gênero e espécie de lagarto, Brasiliguana prudentis, baseado numa maxila esquerda com dentição. O material provém de depósitos da Formação Adamantina aflorantes próximos a cidade de Presidente Prudente, Estado de São Paulo, Brasil. O novo táxon é considerado um iguanídeo não-Priscagamidae+Acrodonta baseado na presença de uma margem anterior do processo nasal do maxilar pouco inclinada e na morfologia maxilar e dentaria mais semelhante à de outros iguanideos que a outros grupos de lagartos (ex. teiídeos). A presente descoberta aumenta a diversidade de lagartos escamados na América do Sul onde o registro fóssil é ainda raro.

On a new peirosaurid crocodyliform from the Upper Cretaceous, Bauru Group, southeastern Brazil

A new crocodyliform from the Upper Cretaceous (Campanian-Maastrichtian) Presidente Prudente Formation of the Bauru Group is described based on two almost complete skulls and mandibles. The material comes from the "Tartaruguito" site, situated at an old railroad between the cities of Pirapozinho and Presidente Prudente, state of São Paulo, Brazil. The new species, Pepesuchus deiseae gen. et sp. nov., is classified in the clade Peirosauridae on the basis of three synapomorphies: the presence of five premaxillary teeth, the anterior two premaxillary alveoli nearly confluent, and the oval cross-section of the jugal along the lower temporal bar. The new taxon increases the outstanding crocodyliform diversity of the Bauru Group, particularly of the Peirosauridae, which might turn out to be one of the most representative clades of gondwanan mesoeucrocodylians.

Um novo crocodilomorfo da Formação Presidente Prudente, Cretáceo Superior (Campaniano-Maastrichtiano) do Grupo Bauru é descrito com base em dois exemplares, consistindo de crânio e mandíbulas quase completos. O material é procedente da localidade conhecida como "Tartaruguito", situada em um antigo ramal ferroviário que ligava as cidades de Pirapozinho e Presidente Prudente, Estado de São Paulo, Brasil. A nova espécie, denominada de Pepesuchus deiseae gen. et sp. nov., é classificada no clado Peirosauridae, com base em três sinapomorfias: presença de cinco dentes pré-maxilares, os dois primeiros alvéolos da pré-maxila quase confluentes e a secção transversal do jugal ao longo da barra temporal inferior oval. O novo táxon aumenta a marcante diversidade de crocodiliformes do Grupo Bauru e dos Peirosauridae, que poderá vir a ser um dos clados mais representativos de mesoeucrocodilianos gondwânicos.