New fish remains from the Araçatuba and Adamantina formations (Upper Cretaceous), Bauru Group, southwestern São Paulo State

SummaryBlind snakes (Scolecophidia) are minute cryptic snakes that diverged at the base of the evolutionary radiation of modern snakes. They have a scant fossil record, which dates back to the Upper Paleocene-Lower Eocene (∼56 Ma); this late appearance conflicts with molecular evidence, which suggests a much older origin for the group (during the Mesozoic: 160–125 Ma). Here we report a typhlopoid blind snake from the Late Cretaceous of Brazil, Boipeba tayasuensis gen. et sp. nov, which extends the scolecophidian fossil record into the Mesozoic and reduces the fossil gap predicted by molecular data. The new species is estimated to have been over 1 m long, much larger than typical modern scolecophidians (<30 cm). This finding sheds light on the early evolution of blind snakes, supports the hypothesis of a Gondwanan origin for the Typhlopoidea, and indicates that early scolecophidians had large body size, and only later underwent miniaturization.

A microvertebrate assemblage from the Adamantina Formation (Bauru Group, Upper Cretaceous) in São Paulo State, Brazil

Remains of a new titanosaur, Aeolosaurus maximus sp. nov., from the Adamantina Formation (Upper Cretaceous), Bauru Group, São Paulo State of Brazil are described. The new species is represented by a single partially articulated skeleton and is characterized by having a well-developed posterior protuberance below the articular area on the anterior and middle haemal arches and a lateral bulge on the distal portion of the articular process of the mid-posterior haemal arches. It shares with other Aeolosaurus species the presence of prezygapophyses curved downward on anterior caudal vertebrae and haemal arches with double articular facets set in a concave posterodorsal surface. These two characteristics are interpreted here as synapomorphies for the genus Aeolosaurus. The new diagnosis for the genus Aeolosaurus does not support the inclusion of Gondwanatitan within Aeolosaurus as previously proposed by some authors. The phylogenetic analysis recovered the two Aeolosaurus from Argentina as sister groups with A. maximus and Gondwanatitan as progressively more basal taxa (Gondwanatitan (A. maximus (A. rionegrinus, A. colhuehuapensis))). Additionally, according to the results of the phylogenetic analysis performed in this work, the taxa Panamericansaurus, Rinconsaurus, and Maxakalisaurus are also nested within Aeolosaurini, being more basal than Aeolosaurus and Gondwanatitan. On the basis of the stratigraph-ical range of the Aeolosaurus occurrences in Argentina and the age proposals based on microfossils for the Bauru Group, it is assumed a Campanian–Maastrichtian age for the top of the Adamantina Formation for the Monte Alto region in São Paulo State and the bottom of the Marília Formation in Peirópolis, Minas Gerais State—the places where Aeolosaurus remains have been reported in Brazil.

This study presents the oldest record of Acanthocephala parasite eggs in coprolites preliminary assigned to Crocodyliformes, recovered in the region of Santo Anastácio Municipality, Southwestern São Paulo State. For this, a paleoparasitological investigation was carried out on 53 mineralized coprolites (complete or fragmented), with round shape or cylindrical shape of rounded or pointed ends, 0.2 - 3.9 cm in length x 0.1 - 2.4 cm in diameter, 3.7 grams in weight, and absence of food remains. Individual samples of the surface and internal portions of each coprolite were extracted by electric drill, dissociated with Cloridic Acid 10% solution, washed with Distilled Water, and filtered in granulometric screen Mesh / Tyler 325. After laboratory processing, the sediments retained on the granulometric screen was studied with Glycerin under optical microscopy, and the presence of four Acanthocephala eggs could be observed in sample of only one of these ichnofossils. All specimens were well preserved and showed 72.5 - 85 µm in length x 27.5 - 50 µm in width, elliptical shape, three concentric and thick shells, and embryos in their interior. This study inaugurates investigations and knowledge about Paleoparasitology in Crocodyliformes coprolites from the Bauru Group, Upper Cretaceous from the Paraná Basin.

Dinosaurs remains from western São Paulo state, Brazil (Bauru Basin, Adamantina Formation, Upper Cretaceous)

Mariliasuchus amarali Carvalho &amp; Bertini, 1999 , a Mesoeucrocodylia from the Adamantina Formation (Bauru Basin, Upper Cretaceous) shows some adaptative features to terrestrial environments: short and high skull, lateral orbits, frontal external nares and reduction of the dental formula with specialization of the tooth crown morphology in incisiform, caniniform and molariform teeth. It has been included in the infraorder Notosuchia Gasparini, 1971. Three specimens of Mariliasuchus amarali, found near the municipality of Marília, São Paulo State were analysed. One of them, holotype of Mariliasuchus amarali (UFRJ DG 50-R), is a juvenile crocodylifom whereas the other two (UFRJ DG 105-R and UFRJ DG 106-R) are adult animals. These fossils allowed an analysis of the ontogenetic development patterns of this species. It was performed a comparison betweeen the mandibular, laterotemporal and supratemporal fenestrae and the skull sculpturing in the three specimens. The results show that Mariliasuchus acquire in the course of its ontogeny a thicker and stronger skull. The caudal migration of the laterotemporal fenestra and the size increase of the supratemporal fenestra probably indicate a wider use or strength of the adductor muscles during seizing and food processing.

Physa mezzalirai n. sp. (Family Physidae, Order Basommatophora), a fresh-water gastropod is described from sand-silty beds of Adamantina Formation (Bauru Basin), Late Cretaceous of São Paulo State, Brazil. This is the first occurrence of gastropods in the analyzed region and to this geological unit where the paleontological content is mostly known by the big turtle bones and shells, and by other vertebrate remains. These finding attests the paleontological potential of Adamantina Formation to the study of invertebrate fossils, nearly neglected in the moment, and could help in the refinement of fl uviolacustrine paleoenvironmental and about the paleoecology during the time of Bauru Group depositon. Key words: Mollusca, Gastropods, systematic, Adamantina Formation, Late Cretaceous, Brazil.

Taphonomy of a Baurusuchus (Crocodyliformes, Baurusuchidae) from the Adamantina Formation (Upper Cretaceous, Bauru Basin), Brazil: Implications for preservational modes, time resolution and paleoecology

The fluvial deposits of the Adamantina Formation (Upper Cretaceous, Bauru Group) have produced a rich fossil vertebrate record of fishes, amphibians, lizards, snakes, turtles, dinosaurs and mammals. However, the record of notosuchians (Crocodylomorpha) is remarkable in terms of both diversity and number of findings. Here, we report a large number of new coprolites found in association with skeletons of crocodylomorphs from the Adamantina Formation in the cities of Jales and Fernandópolis, São Paulo State, Brazil, and discuss their meaning for the understanding of feeding habits of their producers. The coprolites from Jales were found mostly together with adult skeletons of baurusuchids and crocodylomorph egg clutches, while the coprolites from Fernandópolis are associated with adult sphagesaurids and juvenile and adult baurusuchid skeletons, and rare crocodylomorph egg clutches. Forty-one coprolites were analysed encompassing different degrees of preservation. The X-ray diffraction showed the coprolites are comprised mainly of fluorapatite. The presence of bone fragments in some coprolites, together with their typical crocodylomorph cylindrical shape with rounded ends, strongly indicates that Baurusuchidae not only are carnivores, but that also ingested large bone fragments. On the other hand, the coprolites assigned to Sphagesauridae generally show a more complex chemical composition and present plant remains within which indicate this group, at least in part, fed on plants. Our results reinforce the importance of these ichnofossils as an independent source of information on the feeding habits of their producers and add new evidence these two groups of crocodylomorphs fed on different food sources.

Theropod teeth from the Adamantina Formation (Bauru Group, Upper Cretaceous), Monte Alto, São Paulo, Brazil

The Bauru Group is a sequence at least 300 m in thickness, of Cretaceous age (Turonian- Maastrichtian), located in southeastern Brazil (Bauru Basin), and consists of three formations, namely Adamantina, Uberaba and Marilia. Throughout the Upper Cretaceous, there was an alternation between severely hot dry and rainy seasons, and a diverse fauna and flora was established in the basin. The ichnofossils studied were found in the Adamantina Formation outcrops and were identified as Arenicolites isp., ?Macanopsis isp., Palaeophycus heberti and Taenidium barretti, which reveal the burrowing behavior of the endobenthic invertebrates. There are also other biogenic structures such as plant root traces, coprolites and vertebrate fossil egg nests. The Adamantina Formation (Turonian-Santonian) is a sequence of fine sandstones, mudstones, siltstones and muddy sandstones, whose sediments are interpreted as deposited in exposed channel-bars and floodplains associated areas of braided fluvial environments.

Abstract: Compared with crocodylomorph body fossils, the record of fossil crocodiloid eggs is scarce and poorly understood, a gap partially attributed to their typically thin eggshell, which is not conducive to preservation. A remarkable new association of well‐preserved eggs and eggshells from the Adamantina Formation (Bauru Group, Upper Cretaceous) is described and compared to other known materials, while the significance of their unique oological features is discussed. These eggs constitute a new ootaxon,Bauruoolithus fragilisoogen. et oosp. nov., diagnosed by the following characteristics: elongate and elliptical egg with blunt ends; length‐to‐diameter ratio of 1:0.55; outer surface slightly undulating; shell thickness ranging from 0.15 to 0.25 mm; pore openings elliptical or teardrop‐shaped, ranging from 30 to 80 μm in diameter; and shell units wider than higher, with the interstices forming an obtuse triangle. Specimens ofBauruoolithusalso show only slight signs of extrinsic degradation that, coupled with the evidence that some of them constitute hatched eggs, suggests that the egg‐laying taxon had a different pattern of egg incubation, in which the hatchling could break through the rather thin eggshell relatively easily and that the extrinsic degradation of the eggshell was not necessary. This contrasts with the pattern of incubation for all other known crocodylomorphs and crocodiloid eggs, where extrinsic degradation is a key component of the hatching process.

A new Baurusuchidae (Notosuchia, Crocodyliformes) from the Adamantina Formation (Bauru Group, Upper Cretaceous), with a revised phylogenetic analysis of Baurusuchia

Morphological and paleohistological description of a new Baurusuchidae specimen from the Adamantina Formation, Upper Cretaceous of Brazil

Background. A new podocnemidid taxon from the Adamantina Formation (Campanian to Maastrichtian), Bauru Group - Paraná Basin (southeastern Brazil) is presented. Some multifragmented specimens were discovered near 30 years ago, in the region of Álvarez Machado (State of São Paulo) on the farm of Mr. Yoshitoshi Myzobuchi (a.k.a "Myzobuchi Site"), and they were mounted piece by piece of a huge puzzle. The remains comprise two incomplete carapace, 4 fragmented plastra, some cervical vertebrae, scapular and pelvic girdles, and limb bones of at least 4 specimens. The sauropod Gondwanatitan faustoi was described from this same site that also provided some crocodile remains. Methods. This new Adamantina taxon was codified according Gabriel S. Ferreira’s pleurodire dataset (unpublished MSc thesis) which comprises an extensive taxonomic sampling (85 taxa, 226 characters, some multistate), including fossil and recent taxa from all pleurodiran lineages. Three software packages (PAUP*, WinClada and TNT) were used to evaluate its phylogenetic position. Results. All searches resulted on most parsimonious trees of same lenght (1011 steps), and similar strict consensus topology. The new Adamantina taxon is in Bairdemys-Stereogenys lineage, after the Podocnemis split and sequentially between the eocenic Egyptian fossil Neochelys fajumensis and the recent South American Peltocephalus dumerilianus. Discussion. The plastral bones of this new taxon are relatively thick and the most striking feature is the ankylosed suture between the pubis and the xiphiplastron. In any other pleurodire the articular faces between the pubis and the xiphiplastron have several osseous lamellae but in the new taxon this ankylosed articulation is simply broken (to the contrary, the articular faces between the ischium and xiphisplastron are preserved and have these lamellae). This apparently is also the case for Podocnemis harrisi Pacheco, 1910, which is considered a nomen dubium by several authors. It also has a thick xiphiplastron, which is the only holotypic bone preserved (but lost long time ago) and shows the pubic articular face apparently with no lamellae, but the ischiadic one clearly showing them, as illustrated in Pacheco (1910). It also shows some minor differences in the morphology with an intumescence mainly in the region of the pubic articular face which is absent in the present specimens. Podocnemis harrisi is also from Adamantina Formation, but from the City of Colina away 300 km NE from the City of Álvarez Machado, and the ankylosed puboxiphiplastral suture suggest a close phylogenetic relationship between both that is here expressed as a new combination with the Álvarez Machado new nominative genus.