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The reconstruction of jaw muscles is critical in establishing potential cranial functions; however, myological studies of extinct groups that have no descendants are difficult to perform and test. This is particularly true for pterosaurs, a group of extinct flying reptiles that present a plethora of cranial morphologies, suggesting different functions and feeding habits. Here we present a first attempt to reconstruct the adductor musculature of the pterodactyloid skull in detail, using osteological correlates and the extant phylogenetic bracketing method. Using these reconstructions, we estimate bite force for nine selected species and investigate implications for potential dietary habits.

The Tapejarinae are edentulous pterosaurs that are relatively common in Cretaceous continental deposits in South America, North Africa, Europe, and China (mostly Early Cretaceous). The Chinese Jiufotang Formation is particularly rich in tapejarine specimens, having yielded over 10 described specimens and dozens of undescribed ones. For the Jiufotang Formation, a total of seven nominal tapejarid species and two genera have been proposed. Some debate exists over how many of those are valid or, alternatively, sexual or ontogenetic morphs of fewer (or even a single) species. Despite the abundance of specimens and the relevant taxonomic problems involved, detailed revisions of the matter are still lacking. This is partly due to the relatively scarce knowledge on the comparative osteology of theSinopteruscomplex, which is hampered by the fact that most specimens have been only preliminarily described. In this contribution, we present a new postcranial specimen, D3072, which we attribute to the type-species of the genus,Sinopterus dongi. This new specimen helps shed some new light in the osteology ofSinopterus dongi, hopefully serving as a basis for future comparative studies involving further specimens and other proposed species and, subsequently, taxonomic revisions.

Ornithocheirus wiedenrothi, from the Hauterivian (Early Cretaceous of Germany), is a taxon represented by three-dimensional remains of the lower jaw and wing elements. Its phylogenetic affinities h...

The Solimões Formation is a southwest geological unit of the Brazilian Amazon, being well-known for the Cenozoic giant eusuchian fossils. Among the eight species of Crocodylia described for this formation, the alligatoroid Purussaurus brasiliensis is the best known worldwide due to its enormous size. The holotype was described in 1892 by Barbosa-Rodrigues, composed by a right hemimandible. Later, two other species were assigned to the genus, but the loss of the type specimen brought a series of doubts and discussions about genus and species validity. Here, we provide a historical reconstruction of the genus Purussaurus, especially with a new description of the specimen DGM 527-R, which was first described by L. I. Price. We also provide a review of Purussaurus brasiliensis as a valid species, highlighting the importance of the paleontologist Diogenes de Almeida Campos to the preservation, study availability and divulgation of the specimen. From the six mandibular features discussed, at least two are putative synapomorphies for the genus: the false ziphodont teeth and the thinning of the medial surface of the mandible posterior to the fourteen alveoli, while the lateral surface become laterally expanded from ninth alveoli to behind. The review of the other species of the genus was aggravated due to little sampling of photos and low quality of those contributions. Finally, the curatorial efforts initiated by Price and kept for decades by Campos turned possible the revision of DGM 527-R, an important specimen for understanding the paleobiology and evolution of the genus, and, consequently P. brasiliensis. Such importance was recognized here scientifically and by Campos when considered this specimen as the center-piece of the exhibition in honor of the centenary anniversary of Price.

Anurognathids are an elusive group of diminutive, potentially arboreal pterosaurs. Even though their monophyly has been well-supported, their intrarelationships have been obscure, and their phylogenetic placement even more. In the present work, we present a new genus and species from the Middle-Late Jurassic Tiaojishan Formation, the third nominal anurognathid species from the Jurassic of China. The new species provides new information concerning morphological diversity for the group. Furthermore, we provide a new phylogenetic analysis incorporating into a single data set characters from diverging phylogenetic proposals. Our results place them as the sister-group of Darwinoptera + Pterodactyloidea, as basal members of the Monofenestrata.

A recent publication of fossil bones of titanosaurs assigned to Aeolosaurini from the Morro do Cambambe site (Mato Grosso state, Brazil, Upper Cretaceous) reported anomalous growth in some of them. Here, we present osteohistological sections of elements to understand not only the microstructure and growth of such bones, but also the nature of those anomalies. Among them, we selected one cervical and one mediumposterior dorsal rib, and a haemal arch. The primary bone of all specimens consisted of a variation of the fibrolamellar complex, with the inner cortex being rich in woven bone with dispersed longitudinal canals, while the outer cortex was parallel-fibred with rows of longitudinal canals, interlayered by Lines of Arrested Growth. We identified a maximum of two Lines of Arrested Growth in the cervical rib and haemal arch, and four in the dorsal rib. The haemal arch shows an External Fundamental System in most sections. The advanced remodelling and variation of the fibrolamellar bone in the cortex suggests that all the specimens represent individuals that reached sexual maturity. However, the haemal arch was distinct due to the wide distribution of External Fundamental System. Based on the microstructure, we identified a subadult semaphoront, and probably an adult. The dorsal rib exhibited periosteal and endosteal outgrowth. Such microstructure was assigned to a reactive bone due to an intra-thoracic infection (a pneumonia, probably related to a tuberculosis), which is the first report in a non-avian dinosaur. The microstructure resembles the medullary bone recovered in dinosaurs, which suggests that further studies of medullary bone in thoracic bones should also regard the pathological cases. En una reciente publicación de los huesos fósiles de titanosaurios asignados al clado Aeolosaurini provenientes del yacimiento de Morro do Cambambe (estado de Mato Grosso, Brasil, Cretácico Superior), se reconocieron anormalidades en el crecimiento de algunos de ellos. En el presente trabajo presentamos cortes osteohistológicos de elementos para entender no sólo la microestructura y crecimiento de los mismos, sino también la naturaleza de aquellas anomalías. Entre ellos, seleccionamos una costilla cervical y una costilla dorsal media posterior, así como un arco hemal. El hueso primario de todos los especímenes comprendía una variación del complejo fibrolamelar, siendo la corteza interna rica en tejido reticular óseo con canales longitudinales dispersos, mientras que la corteza externa tenía fibras paralelas con hileras de canales longitudinales, intercaladas por líneas de crecimiento detenido. Identificamos un máximo de dos líneas de crecimiento detenido tanto en la costilla cervical como en el arco hemal, y cuatro en la costilla dorsal. El arco hemal muestra un Sistema Externo Fundamental en la mayoría de las secciones. La remodelación avanzada y la variación del hueso fibrolamelar en la corteza, se sugiere que todas los especímenes alcanzaron la madurez sexual. Sin embargo, el arco hemal fue distinto debido a la amplia distribución de Sistema Externo Fundamental. Con base en la microestructura, identificamos un semaforonte subadulto, y probablemente a un adulto. La costilla dorsal mostró una excrecencia perióstica y endosteal. Dicha microestructura se ha identificado con un hueso reactivo a una infección intratorácica (una neumonía, probablemente relacionada con una tuberculosis), que es el primer informe de un dinosaurio no aviano. La microestructura se asemeja al hueso medular recuperado en los dinosaurios, lo que sugiere que los estudios posteriores del hueso medular en los huesos torácicos también deberían considerar los casos patológicos.

Aerotitan sudamericanus, from the Upper Cretaceous of the Neuquen Basin (Patagonia, Argentina), is known from a partial jaw fragment which has been interpreted as either an azhdarchid upper jaw, azhdarchid lower jaw, or thalassodromine upper jaw (as the sister-group of Alanqa). Here, we compare it in detail to upper and lower jaws of taxa belonging to all azhdarchoid lineages. It possesses a lateral angle (angle of divergence between occlusal and apex margins in lateral view) that is too low for an upper jaw of any azhdarchoid group. It further differs from thalassodromine upper jaws in exhibiting a convex occlusal margin (in lateral view), a sulcate occlusal surface, and lacking a sagittal crest. Furthermore, Aerotitan differs from Alanqa in 5 aspects: (1) occlusal margin shape in lateral view (convex in Aerotitan, straight in Alanqa), (2) median dentary eminence shape (slender in Aerotitan, posteriorly expanded in Alanqa), (3) median dentary eminence position (anterior in Aerotitan, close to the posterior end of the symphysis in Alanqa), (4) tomial edges shape (thick and blunt in Aerotitan, thin and sharp in Alanqa), and (5) occlusal surface anterior to the median eminence (cross-section concave in Aerotitan, slightly convex in Alanqa). We also conclude that the holotype of A. sudamericanus is a match for an azhdarchid lower jaw, being extremely similar to that of Mistralazhdarcho. When scored as a lower jaw in our phylogenetic analysis, it is recovered as a close relative of Mistralazhdarcho, in a polytomy that also includes Arambourgiania. In contrast, Alanqa is recovered as the sister-group of Keresdrakon, both located at the base of a broader clade of long-snouted azhdarchoids that also includes chaoyangopterids and azhdarchids, to the exclusion of tapejarines and thalassodromines.

In the present paper, we review the fossil record of the Hydrometridae (Hemiptera, Gerromorpha) and present a new species from the Early Cretaceous Crato Formation of Northeastern Brazil, Christometra paradoxa gen. et sp. nov. This species is based on a new specimen (a female), as well as a previously figured one (a male), providing a rare case of preservation of sexually dimorphic features in the fossil record. This is the third species coming from this deposit, which is Aptian-Albian in age and the oldest deposit to have yielded hydrometrids so far. Only five other Mesozoic species are known, being slightly younger in age (Cenomanian). So far, phylogenetic analyses have recovered Cretaceous hydrometrids as basal relative to Cenozoic genera but, Christometra paradoxa exhibits several advanced characteristics that unite it in a clade together with the extant genera Hydrometra and Bacillometroides, in a more derived position than any previously known fossil hydrometrid.The present publication is re...

A new istiodactylid pterosaur,Nurhachius lueisp. nov., is here reported based on a complete skull with mandible and some cervical vertebrae from the lower part of the Jiufotang Formation of western Liaoning (China). This is the second species ofNurhachius, the type-species beingN. ignaciobritoifrom the upper part of the Jiufotang Formation. A revised diagnosis of the genusNurhachiusis provided, being this taxon characterized by the presence of a slight dorsal deflection of the palatal anterior tip, which is homoplastic with the Anhangueria andCimoliopterus. N. lueisp. nov. shows an unusual pattern of tooth replacement, with respect to other pterodactyloid species. The relationships within the Istiodactylidae and with their closest taxa are investigated through a phylogenetic analysis by parsimony.

Pterosaurs, which lived during the Mesozoic, were the first known vertebrates to evolve powered flight.1,2 Arboreal locomotion has been proposed for some taxa,3,4 and even considered to have played a role in the origin of pterosaur flight.5,6 Even so, there is still need for comprehensive quantitative ecomorphological analyses.3,4 Furthermore, skeletal adaptations correlated to specialized lifestyles are often difficult to recognize and interpret in fossils. Here we report on a new darwinopteran pterosaur that inhabited a unique forest ecosystem from the Jurassic of China. The new species exhibits the oldest record of palmar (or true) opposition of the pollex, which is unprecedented for pterosaurs and represents a sophisticated adaptation related to arboreal locomotion. Principal-coordinate analyses suggest an arboreal lifestyle for the new species but not for other closely related species from the same locality, implying a possible case of ecological niche partitioning. The discovery adds to the known array of pterosaur adaptations and the history of arborealism in vertebrates. It also adds to the impressive early bloom of arboreal communities in the Jurassic of China, shedding light on the history of forest environments.

Canis rufus is an example of animal whose conservational needs have been questioned because of its possible hybrid status. Control of hybridization has been defended and done in the wild to theoretically save the species. However, control of hybridization may not be the solution. Hybridization may be a phenomenon misconceived by many modern evolutionary biologists, and conservation guidelines over control on anthropogenic impacts may need revisions in order to respect the new perspectives on hybridization’s role in evolution. The term “cladogamy” is being proposed to substitute “hybridization” and to refer to the crossing between two any given clades, due to difficulties from scientists and eventual arbitrary means of separating species from lower taxa.

Thalassodromeus sethi (Pterodactyloidea, Tapejaridae, Thalassodrominae) is a unique pterosaur from the Romualdo Formation, Araripe Basin (Early Cretaceous, Albian). A large sagittal cranial crest (the largest known ossified crest of any pterosaur) and unusual toothless bladed jaws constitute some of its outstanding anatomical features. Its holotype (DGM 1476-R, almost complete skull and mandible in three dimensions) represents one of the largest pterosaur skulls ever found. Here, we provide a detailed osteological redescription of the holotype, which has only been preliminarily described. We also describe and depict for the first time some skeletal regions of Th. sethi, including the occiput, the palatal openings, and a dentary fragment. Finally, in the light of new information concerning this species, we revisited the specimen NMSG SAO 251093 (an incomplete mandible), also from the Romualdo Formation and originally referred to Th. sethi but recently redescribed as a new species of dsungaripterid pterosaur named Banguela oberlii. Here, the analysis of a cast (MN 4703-V) and its inclusion in a phylogenetic analysis recovered NMSG SAO 251093 within the Thalassodrominae, as a sister taxon of Th. sethi and indeed different from it at the species level. We hereby rename it Thalassodromeus oberlii, comb. nov. These considerations provide new data for discussions concerning the morphology of the Tapejaridae, the diversity of the Araripe pterosaur fauna, and the complex evolution of the pterodactyloid palatal region, as well as data for future morphofunctional studies of Thalassodromeus.

A three-dimensional and almost complete pterosaur mandible from the Crato Formation (Early Cretaceous of Northeastern Brazil), Araripe Basin, is described as a new species of a tapejarine tapejarid. Tapejarines are a particular group of toothless pterosaurs, characterized by well-developed cranial crests, downturned rostra, and have been proposed to represent frugivorous flying reptiles. Though comparatively well represented and distributed, the evolutionary history of the group is still poorly known, and the internal relationships of its members are not well understood. The new species here reported, named Aymberedactylus cearensis gen. et sp. nov., adds new data concerning the evolution of the group, concerning their morphology and geographical origin. It differs from known tapejarids due to its unusually elongate retroarticular process and a shallow fossa on the splenial exhibiting distinctive rugose texture. Furthermore, it exhibits a suite of basal and derived conditions within the Tapejaridae, demonstrating how their morphological traits probably evolved and that these forms were even more diverse than already acknowledged. The discovery of Aymberedactylus cearensis sheds new light on the evolutionary history of the Tapejarinae.