Diego Pol

Museo Paleontológico Egidio Feruglio

The Supplemental Data includes a brief summary of the general aspects of the dentition of Manidens condorensis, and six different supplemental figures: 1, recognized areas of bone remodeling in the laterally projected jugal boss on MPEF-PV 3211 and captions for the supplemental figures; 2, inferred areas of origin and insertion for musculature in t...

Heterodontosauridae is a clade that appears early in the ornithischian fossil record, and includes small-bodied, highly specialized species characterized by an unusual heterodont dentition. Although known from relatively few taxa, the early representation of the clade and unsolved phylogenetic relationships within heterodontosaurids and among early...

Herein we report the first record of Purussaurus Barbosa-Rodrigues, 1892 for the Neogene of Argentina. This genus is recorded in Miocene beds of different localities in Colombia, Venezuela, Brazil, and Perú, and includes at least three different species with total body lengths ranging from 8 to 13 m. The material reported here is a partially preser...

In amniotes, the predominant developmental strategy underlying body size evolution is thought to be adjustments to the rate of growth rather than its duration. However, most theoretical and experimental studies supporting this axiom focus on pairwise comparisons and/or lack an explicit phylogenetic framework. We present the first large-scale phylog...

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...

We present a detailed histological study of long bones from an ontogenetic series of Mussaurus patagonicus, an early sauropodomorph from the Lower Jurassic of Argentina. Twenty long bones, including humeri, femora and fibulae, obtained from 13 individuals of different body sizes were sampled for histological analysis. In general terms, the cortical...

Sebecidae is a clade of large carnivorous crocodyliforms that thrived in the Cenozoic and is the only lineage of the diverse and terrestrial group Notosuchia that survived the end-Cretaceous mass extinction event. Sebecus icaeorhinus is the best-known taxon from this clade, both in terms of its cranial and postcranial anatomy (known primarily from...

Jaw muscles are key features of the vertebrate feeding apparatus. The jaw musculature is housed in the skull whose morphology reflects a compromise between multiple functions, including feeding, housing sensory structures, and defense, and the skull constrains jaw muscle geometry. Thus, jaw muscle anatomy may be suboptimally oriented for the produc...

Notosuchia represents a highly diverse lineage of Crocodyliformes usually characterized by the presence of a heterodont dentition. Although the dental anatomy has been thoroughly analysed in some taxa, information regarding tooth microstructure and dental attachment tissue are still poorly explored. With the purpose to obtain new data regarding fee...

Myhrvold et al. suggest that our inference of subaqueous foraging among spinosaurids is undermined by selective bone sampling, inadequate statistical procedures, and use of inaccurate ecological categorizations. Myhrvold et al. ignore major details of our analyses and results, and instead choose to portray our inferences as if they were based on qu...

Early sauropodomorphs were diverse in Gondwana, being particularly well represented in South America. Mussaurus patagonicus is one of the best-known non-sauropod sauropodomorphs that inhabited the Southern Hemisphere. Its importance relies on its phylogenetic position close to Sauropoda and also because it is known from a well-represented ontogenet...

Eusauropods are large-bodied and long-necked dinosaurs that dominated the role of large herbivores in terrestrial ecosystems since at least the late Early Jurassic (Pliensbachian–Toarcian). Their early diversification is best recorded in South America where the best-preserved eusauropods and close relatives from this period of time have been found....

Secondary aquatic adaptations evolved independently more than 30 times from terrestrial vertebrate ancestors1,2. For decades, non-avian dinosaurs were believed to be an exception to this pattern. Only a few species have been hypothesized to be partly or predominantly aquatic3–11. However, these hypotheses remain controversial12,13, largely owing to...

The lower jaw of early tetrapods is composed of several intramembranous ossifications. However, a tendency toward the independent reduction of the number of bones has been observed in the mandible of mammals, lepidosaurs, turtles, crocodiles, and birds. Regarding archosaurs, the coronoid and prearticular bones are interpreted to be lost during the...

The extinct herpetofauna of the Chubut Province is one of the most diverse, temporally and spatially extensive, and well-known extinct faunas in Argentina and South America. These fossils help understanding the evolution of the herpetofauna during more than 180 million years, not only in the Patagonian region, but also in a worldwide scale due to t...

La Formación La Colonia aflora en el borde sureste de la meseta de Somún Curá, en el norte de la provincia de Chubut. Los ambientes de depositación corresponden a fluviales, marino-marginales y marino-someros y se estima una edad entre el Campaniano y el Paleoceno para toda la unidad. Numerosas campañas paleontológicas llevadas a cabo desde princip...

Sauropodomorph dinosaurs were the dominant medium to large-sized herbivores of most Mesozoic continental ecosystems, being characterized by their long necks and reaching a size unparalleled by other terrestrial animals (> 60 tonnes). Our study of morphological disparity across the entire skeleton shows that during the Late Triassic the oldest known...

A new crocodyliform, Sebecus ayrampu, sp. nov., is described based on the rostral region of the skull, mandibular rami, and a distal portion of the femur collected in Paleocene rocks of northwestern Argentina. The new taxon is diagnosed (among other characters) by the presence of a sharp sagittal torus on the palatal surface of the premaxilla and m...

Sauropodomorph dinosaurs dominated the herbivorous niches during the first 40 million years of dinosaur history (Late Triassic–Early Jurassic), yet palaeobiological factors that influenced their evolutionary success are not fully understood. For instance, knowledge on their behaviour is limited, although herding in sauropodomorphs has been well doc...

In this contribution we introduce a new Late Triassic archosaur, Incertovenator longicollum gen. et sp. nov., with an unusual combination of character states that are present in certain early avemetatarsalian and pseudosuchian archosaur clades. The holotype consists of a partial postcranial skeleton, preserving most of the axial skeleton and displa...

Middle Jurassic sauropod taxa are poorly known, due to a stratigraphic bias of localities yielding body fossils. One such locality is Cerro Cóndor North, Cañadón Asfalto Formation, Patagonia, Argentina, dated to latest Early–Middle Jurassic. From this locality, the holotype of Patagosaurus fariasi Bonaparte 1986 is revised. The material consists of...

All modern crocodyliforms (alligators, crocodiles and the gharial) are semi-aquatic generalist carnivores that are relatively similar in cranial form and function. However, this homogeneity represents just a fraction of the variation that once existed in the clade, which includes extinct herbivorous and marine forms with divergent skull structure a...

Notosuchia is a clade of crocodyliforms that was highly successful and diverse in the Cretaceous of Gondwana. Araripesuchus gomesii is a small notosuchian from the Early Cretaceous of Brazil that belongs to Uruguaysuchidae, one of the subgroups of notosuchians that first radiated, during the Aptian–Albian. Here we present a finite element analysis...

Late Jurassic South American theropod faunas are still extremely poorly known, with large-sized ceratosaurids and megalosaurids having been identified on the basis of isolated teeth, whereas the only named taxa, Chilesaurus and Pandoravenator, are probable tetanurans of uncertain affinities. Here we describe two new specimens of medium-sized to lar...

In this work, we present a comparative analysis between Araripesuchus gomesii, a small notosuchian from the Early Cretaceous of Brazil, and Alligator mississippiensis, a living representative of the crocodyliform lineage considered as a model species for herpetological and functional studies. A finite element analysis (FEA), comparing the skull per...

A stegosaurian humerus from the Oxfordian–Tithonian(?) Cañadón Calcáreo Formation of Chubut, Argentina, extends the fossil record of this clade of thyreophoran ornithischian dinosaurs to the Upper Jurassic of South America. The element shares the derived character of an oblique ridge extending from the deltopectoral crest towards the medial distal...

Here we present the first record of a stem-Coracii outside the Holarctic region, found in the early Eocene of Patagonia at the Laguna del Hunco locality. Ueekenkcoracias tambussiae gen. et sp. nov. consists of an incomplete right hind limb that presents the following combination of characters, characteristic of Coracii: relatively short and stout t...

Sauropodomorpha is the first major dinosaurian group that radiated during the Triassic. During this time the group underwent major changes in body plan, including the acquisition of features related to herbivory, large body size, and quadrupedality. By the end of the Late Triassic, approximately 30 million years after the origin of dinosaurs, sauro...

Notosuchia is a clade of crocodyliforms highly successful and diverse in the Cretaceous of Gondwana. Araripesuchus gomesii is a small early notosuchian from the Lower Cretaceous of Brazil in which a finite element analysis (FEA) was performed in this study. The skull and jaw of A. gomesii was reconstructed from CT scans. The FE analysis was perform...

Sauropods, the giant long-necked dinosaurs, became the dominant group of large herbivores in terrestrial ecosystems after multiple related lineages became extinct towards the end of the Early Jurassic (190-174 Ma). The causes and precise timing of this key faunal change, as well as the origin of eusauropods (true sauropods), have remained ambiguous...

Preprint of In Press manuscript of the Osteological redescription of Patagosaurus fariasi

Abelisaurid theropods dominated the predator role across Gondwana during the Late Cretaceous. They are characterized by highly reduced forelimbs and one of the most specialized cranial morphologies among carnivorous dinosaurs, exemplified by a broad skull, short rostrum, high occipital region, and highly kinetic intramandibular joint, suggestive of...

Supplementary material for this article includes micro-CT scan figures and reconstruction of the skull of Spectrovenator ragei n. gen., n. sp., annotated character list, data matrix in TNT format, strict and reduced consensus trees, support analyses, list of synapomorphies, and selected measurements from the skull of Spectrovenator ragei n. gen., n...

Dental replacement in Heterodontosauridae has been debated over the last five decades primarily on indirect evidence, such as the development of wear facets and the position of erupted teeth. Direct observation of unerupted teeth provides unambiguous data for understanding tooth replacement but this has been done only for Heterodontosaurus and Frui...

Crocodylomorpha is a clade that has its origins during the Late Triassic and attained a global distribution early in their radiation. In this context, although limited to few geological units, the South American record has been relevant in the understanding of the origins of the clade. Additionally analyzing the South American crocodylomorph record...

Calcified eggshells protect developing embryos against environmental stress and contribute to reproductive success¹. As modern crocodilians and birds lay hard-shelled eggs, this eggshell type has been inferred for non-avian dinosaurs. Known dinosaur eggshells are characterized by an innermost membrane, an overlying protein matrix containing calcite...

Araripesuchus (Uruguaysuchidae) is a gondwanan mesoeucrocodylian genus that includes several species, distributed in the Cretaceous of Niger (A. wegeneri and A. rattoides), Madagascar (A. tsangatsangana), Brazil (A. gomesii), and Argentina (A. patagonicus and A. buitreraensis). The two Argentinean species came from different localities of the lower...

Almadasuchus figarii is a basal crocodylomorph recovered from the Upper Jurassic levels of the Cañadón Calcáreo Formation (Oxfordian–Tithonian) of Chubut, Argentina. This taxon is represented by cranial remains, which consist of partial snout and palatal remains; an excellently preserved posterior region of the skull; and isolated postcranial remai...

Previous studies on enamel microstructure in Ornithischia have focused on derived lineages of this clade based on species from the northern hemisphere. Here we describe the enamel microstructure of Manidens condorensis from the late Early Jurassic of Argentina that belongs to Heterodontosauridae (interpreted as the basal-most clade of Ornithischia)...

Tetanurae, the most successful clade of theropod dinosaurs, including modern birds, split into three major clades early in their evolutionary history: Megalosauroidea, Coelurosauria, and Allosauroidea. The oldest tetanurans occur in the earliest Middle Jurassic, but the early fossil record of the clade is still poor. Here we report one of the oldes...

The Cretaceous Cerro Barcino Formation (Chubut Group) of Central Patagonia, Argentina has yielded a remarkable fossil vertebrate fauna, which form important components of the South American “mid-Cretaceous” fauna, including titanosauriform sauropod dinosaurs, theropod dinosaurs, crocodyliforms, turtles, and lepidosauromorphs. However, a lack of rob...

Complex structures, like the vertebrate skull, are composed of numerous elements or traits that must develop and evolve in a coordinated manner to achieve multiple functions. The strength of association among phenotypic traits (i.e., integration), and their organization into highly-correlated, semi-independent subunits termed modules, is a result o...

Ontogenetic information is crucial to understand life histories and represents a true challenge in dinosaurs due to the scarcity of growth series available. Mussaurus patagonicus was a sauropodomorph dinosaur close to the origin of Sauropoda known from hatchling, juvenile and mature specimens, providing a sufficiently complete ontogenetic series to...

Gondwanan Jurassic non-neosauropod eusauropods are key for the understanding of sauropod evolution, although their phylogenetic interrelationships remain poorly understood. However, following the revision of the holotype of a key taxon from the early Middle Jurassic Cañadón Asfalto Formation Patagonia, Argentina, Patagosaurus fariasi, the phylogene...

Crocodylomorpha es un clado de arcosaurios que representa el único linaje de pseudosuquios que sobrevive al límite Triásico-Jurásico e incluye a los cocodrilos vivientes. Uno de los taxones más antiguos de este grupo es Trialestes romeri Reig 1963, proveniente de la Fm. Ischigualasto. En el presente trabajo se describe un nuevo crocodilomorfo no-cr...

El registro actual de los eusaurópodos del Jurásico Temprano y Medio es pobre a nivel mundial. El espécimen MPEF-PV 3301-1 colectado en la localidad de Cañadón Bagual (Formación Cañadón Asfalto, Chubut) confirmaría un origen del clado Eusauropoda mucho antes de lo que se creía (Toarciano), y es destacable que, además de material apendicular, se pre...

The Mkv evolutionary model, based on minor modifications to models of molecular evolution, is being increasingly used to infer phylogenies from discrete morphological data, often producing different results from parsimony. The critical difference between Mkv and parsimony is the assumption of a "common mechanism" in the Mkv model, with branch lengt...

This analysis of the long bone microstructure of Antetonitrus ingenipes fills a crucial gap in our understanding of the growth dynamics of sauropodomorph dinosaurs. The bone histology of basal Sauropodomorpha are often characterized by zonal tissue, and contrasts with that of more derived sauropod taxa which show a shift toward the deposition of un...

New materials of the ornithischian dinosaur Manidens condorensis highlight a strong heterodonty between the upper and lower dentitions and reveal a novel occlusion type previously unreported in herbivorous dinosaurs. The diamond-shaped maxillary teeth have prominent cingular entolophs in a V- to Z-shaped configuration that are absent in dentary tee...

Dinosaurs dominated the terrestrial ecosystems for more than 140 Myr during the Mesozoic era, and among them were sauropodomorphs, the largest land animals recorded in the history of life. Early sauropodomorphs were small bipeds, and it was long believed that acquisition of giant body size in this clade (over 10 tonnes) occurred during the Jurassic...

Protosuchids are known from the Late Triassic to the Early Cretaceous and form a basal clade of Crocodyliformes. We report here a new protosuchid crocodyliform, Coloradisuchus abelini, gen. et sp. nov., from the middle Norian Los Colorados Formation, La Rioja, northwestern Argentina. Our phylogenetic analysis recovers Coloradisuchus abelini within...

The dentition of Manidens condorensis Pol, Rauhut and Becerra, 2011, from the Cañadón Asfalto Formation (Early Jurassic) is unique among ornithischians, with clear differences between maxillary and dentary teeth. This work describes the dental enamel microstructure of this species (specimens MPEF-PV 10862, 10863, 10865, 3821, 10823 and 10864), the...

Micro-Computed Tomography scanning of the holotype of Manidens condorensis (Pol, Rauhut and Becerra, 2011; MPEF-PV 3211) provided new data on the anatomy of this species. The micro-CT information allows the identification of the previously unknown maxillary dentition for the species, bearing at least eight teeth. These teeth are low at their apical...

The Bajo de la Carpa Formation (Santonian) of the Neuquén basin (southwestern Argentina) has one of the most complete crocodyliform records of South America, together with the Adamantina and Marília formations of Brazil. In this contribution we report two fragmentary individuals from two different localities of the Bajo de la Carpa Formation: a mid...

Eusauropods were a group of herbivorous dinosaurs that evolved during the Early Jurassic and dominated the terrestrial ecosystems throughout the Jurassic and Cretaceous. A peak of diversity is represented by the Late Jurassic, when most of the lineages of the derived clade, Neosauropoda, are represented. Different lineages of eusauropods differ in...

Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and...

Table S4. Results for glenohumeral joint moment arms (in metres) of major muscle groups in the resting pose for Mussaurus and Crocodylus.

Table S5. Results for elbow joint moment arms (in metres) of major muscle groups in the resting pose for Mussaurus and Crocodylus.