Abstract Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered several well-preserved fossils of these animals. They are largely recognized for terrestrial life and specialized feeding habits, frequently presenting bizarre taxa such as Comahuesuchus. A new species, Comahuesuchus bonapartei n. sp. (MUCPv 597; cast MN), is described from geological strata of Sierra Barrosa Formation (Upper Turonian) and Portezuelo Formation (Lower Coniacian) of Lake Barreales, Patagonia, Argentina. The new fossil comprises a right dentary bone that shares important and unique anatomical features with specimens of Comahuesuchus brachybuccalis, such as the presence of a well-marked shelf on the lateral surface of the bone; a flat, low, and wide mandibular symphysis; an enlarged, labiolingually compressed caniniform tooth at caudal position in the dentary; the presence of serrated mesial and distal carinae in the caniniform with a faceted labial surface, and the absence or extremely reduction in number of the postcaniniform dentition. C. bonapartei differs from C. brachybuccalis in having individual dentary alveoli, rather a dentition set in groove. Phylogenetic analyses support a sister-relationship between both species, which are well nested within notosuchians.

Abstract CT scans of the type braincase of Limaysaurus tessonei (MUCPv-205) allowed the first study of the endocranial cavities (brain and inner ear) for this South American taxon. Comparisons of the cranial endocast of L. tessonei with other sauropods indicate that 1) South American rebbachisaurids are more similar to each other than to Nigersaurus, and 2) certain association of traits are present in all known rebbachisaurid cranial endocasts, such as lack of an enlarged dorsal expansion, poorly laterally projected cerebral hemispheres, presence of a small flocculus of the cerebellum, markedly long passage for the facial nerve (CN VII), markedly inclined pituitary, and presence of a passage for the basilar artery communicating the floor of the endocranial cavity and the pituitary fossa. The relatively enlarged olfactory region indicates that smell was an important sense for this group of dinosaurs, suggesting different olfactory capabilities when compared to coeval titanosaurs.

Abstract We describe a dentary of a new titanosaur sauropod, Baalsaurus mansillai, gen. et sp. nov. from the Late Cretaceous of Patagonia, Argentina. The material comes from the Portezuelo Formation, Neuquén Group. Titanosaur sauropods lower jaws are scarce and only nine taxa with dentaries have been described. There are two types of morphology in titanosaur dentaries; “L” shaped or “U” shaped based on the shape, without a phylogenetic issue. In this paper; we recognize a new taxa, Baalsaurus mansillai, represented by an “L” shaped dentary with three apomorphic characters that are not present in other taxa: dentary alveoli with 10 teeth in the anterior ramus, a ventrally and anteriorly inclined symphysis and a wide ventral Meckelian groove surrounded by a thin lamina that forms a keel on the ventral border of the dentary.

ABSTRACT A new azhdarchoid pterosaur from the Upper Cretaceous of Patagonia is described. The material consists of an incomplete edentulous lower jaw that was collected from the upper portion of the Portezuelo Formation (Turonian-Early Coniacian) at the Futalognko site, northwest of Neuquén city, Argentina. The overall morphology of Argentinadraco barrealensis gen. et sp. nov. indicates that it belongs to the Azhdarchoidea and probable represents an azhdarchid species. The occlusal surface of the anterior portion is laterally compressed and shows blunt lateral margins with a medial sulcus that are followed by two well-developed mandibular ridges, which in turn are bordered laterally by a sulcus. The posterior end of the symphysis is deeper than in any other azhdarchoid. This unique construction of the lower jaw suggests the existence of an elaborate interlocking mechanism with the upper jaw. Furthermore, although speculative, it is advocated here that Argentinadraco barrealensis might have used the lower jaw to obtain its prey by cutting or ploughing through unconsolidated sediment in shallow waters, a feeding behavior not previously proposed for pterosaurs.

Although important dinosaur specimens have been recently described from Brazil, the theropod record in this county is still rather scarce, particularly from Cretaceous strata. Here we describe a complete right tibia (MCT 1783-R) from the Marilia Formation (Maastrichtian, Bauru Basin) near Peiropolis (Uberaba, Minas Gerais). This is the best theropod specimen recovered from this unit after five decades of collecting. MCT 1783-R shows a well developed cnemial crest with a lobular distal end, that projects significantly above the proximal articular surface, features that are characteristic of the Abelisauroidea. It further shows unique characters such as a marked asymmetry of lateral and medial condyles in posterior view, and a very deep triangular articular face for the astragalus, suggesting that it represents a new taxon.

A pesar de que importantes especímenes de dinosaurios de Brasil se han descrito recientemente, el registro de terópodos en este país es todavía bastante escaso, especialmente en los estratos del Cretácico. Aqui reportamos una tibia derecha completa (MCT 1783-R) de la Formación Marilia (Maastrichtiano, Cuenca Bauru) en el área de Peirópolis (Uberaba, Minas Gerais). Este es el mejor material de terópodo recuperado de esta unidad en cinco décadas de recolección. MCT 1783-R muestra una cresta cnemial bien desarrollada con un extremo distal lobular, proyectado significativamente por encima de la superficie articular proximal, los cuales son rasgos característicos de Abelisauroidea. Muestra, además, algunas características únicas, como una marcada asimetría de los cóndilos medial y lateral en el lado posterior y una cara triangular articular muy profunda por el astrágalo, sugiriendo que representa un nuevo taxón.

Aqui reportamos um novo pequeno teropodo deinonicosauriano, Pamparaptor micros gen. et sp. nov. do Cretacéo Superior da Patagônia, Argentina. Pamparaptor exibe uma estrutura pedal previamente desconhecida entre os deinonicosaurídeos da América do Sul. O novo material fornece uma nova evidencia sobre a diversidade morfológica e taxonômica dos deinonicosaurídeos patagonicos. O Paparaptor e o menor deinonicosaurídeo não-aviano patagonico, medindo provavelmente entre 0,50-0,70 metros de comprimento. A construção pedal lembra aquela de Troodontídeos ou Dromaeosaurídios basais. Entretanto, ate agora, consideramos Paparaptor um Dromaeosaurídeo patagonico peculiar com o pe similar ao de Troodontídeos.

Here we report on a new small deinonychosaurian theropod, Pamparaptor micros gen. et sp. nov., from the Late Cretaceous of Patagônia, Argentina. Pamparaptor micros exhibits a pedal structure previously unknown among South Américan deinonychosaurians. The new material provides new evidence about the morphology and taxonomic diversity of Patagônian deinonychosaurs. Pamparaptor is the smaller non-avialae Patagônian deinonychosaur, probably with about 0.50-0.70 meters, long. The pedal construction resembles, that of Troodontid or basal Dromaeosaurids. Nevertheless, up to now, we considered Pamparaptor a peculiar Patagônian Dromaeosaurid with troodontid-like pes.

A new hadrosauroid taxon from the Late Cretaceous Allen Formation is erected, on the basis of abundant cranial and postcranial material from the Salitral Moreno locality of the Rio Negro Province, Argentina. The new taxon is here named as Willinakaqe salitralensis gen. et sp. nov., which is characterized by having an autapomorphous premaxilla with a long and convex rostrolateral surface rostral to the narial fossa and associated postcrania developing an unique character combination, including: dorsal vertebrae with a shallow fossa upon the base of the transverse processes; sacral and proximal caudal neural spines more than three times the height of the centrum; distal region of the postacetabular process of ilium ventrally deflected, among others. This new hadrosauroid closely resembles Secernosaurus koerneri, the other valid hadrosauroid species from South America, based in several synapomorphies, as: angle greater than 115° between the lateral margin of the facet for scapular articulation and the glenoid in the coracoid; supra-acetabular process of the ilium asymmetrical, caudodorsal margin of ilium with a well-defined ridge continuous with the dorsal margin of the proximal region of the postacetabular process. Moreover, previous records of Lambeosaurinae from the Late Cretaceous of South America are referred to W. salitralensis, and thus, the presence of lambeosaurines in this continent is here rejected. Accordingly, Willinakaqe salitralensis gen. et sp. nov. is currently the only hadrosauroid species reported from the Allen Formation.

Se erige un nuevo taxón de hadrosauroideo del Cretácico Superior de la Formación Allen, en base a abundante material craneal y postcraneal de la localidad de Salitral Moreno, en la Provincia de Río Negro, Argentina. El nuevo taxón es denominado Willinakaqe salitralensis gen. et sp. nov., y se caracteriza por tener un premaxilar autapomórfico con una superficie rostrolateral alargada y convexa rostral a la fosa narial y postcráneos asociados con una combinación de caracteres únicos, que incluye: vértebras dorsales con una fosa poco profunda en la base de los procesos transversos, espinas neurales sacras y caudales proximales más de tres veces más altas que el centro; región distal del proceso postacetabular del ilion desviada ventralmente, entre otros. Este nuevo hadrosauroideo es muy similar a Secernosaurus koerneri, la otra especie válida de hadrosauroideo de América del Sur, con el que comparte varias sinapomorfías, como: ángulo mayor que 115 ° entre el borde lateral de la faceta articular escapular y la superficie glenoidea en el coracoides, proceso supra-acetabular del ilion asimétrico, margen caudodorsal del ilion con una cresta bien definida continua con el margen dorsal de la región proximal del proceso postacetabular. Los registros asignados anteriormente a Lambeosaurinae del Cretácico Tardío de América del Sur son referidos a Willinakaqe salitralensis gen. et sp. nov., y por lo tanto, se rechaza la presencia de lambeosaurinos en este continente. En consecuencia, Willinakaqe salitralensis gen. et sp. nov. es actualmente la única especie de hadrosauroideo reportada en la Formación Allen.

We describe sixteen theropod dinosaur trackways from site III (Lower Cretaceous?) of the Quebrada Cha-carilla in the ChacariUa Formation (Jurassic-Lower Cretaceous), northern Chile. The trackbed belongs to a meandering river environment, with recurrent track assemblages. We find that the main direction of the ichnites from site III parallels that of water flow. Two theropod footprint morphotypes are recognized: A) digit II and IV occupying about 0.5 times the total footprint length, and B) digit II and IV occupying less than 0.35 times the total footprint length. We estimate similar speed (~7 km/h) for the two parallel theropod trackways of morphotype A, suggesting synchronized walking. We also describe some of the largest theropod footprints from South America (>60 cm), which are all of morphotype B

Se describen dieciséis pistas de dinosaurios terópodos localizadas en el sitio III (Cretácico Inferior?) de la Formación ChacariUa (Jurásico-Cretácico Inferior) en Quebrada ChacariUa, norte de Chile. La unidad con huellas fue depositada en un ambiente de río meandriforme y presenta recurrentes niveles con asociaciones de trazas. Las icnitas tienen una dirección paralela a la dirección del flujo de agua. Dos morfotipos de huellas de terópodos fueron reconocidos: A) Con los dígitos II y IV, ocupando cerca de 0,5 veces el largo total de la huella y B) con los dígitos II y IV ocupando menos de 0,35 veces la longitud total de la huella. Estimaciones de similar velocidad (~7 km/h) de dos pistas paralelas pertenecientes al morfotipo A, sugieren caminata sincronizada. Además, describimos algunas de las huellas de terópodos más grandes de América del Sur (>60 cm), las que corresponden al morfotipo B

Um depósito fóssil na região norte da Patagônia (Neuquén, Argentina) revela um ecossistema nunca antes registrado a este nível de detalhes em depósitos do Cretáceo Superior. Uma diversidade e abundância extraordinária de fósseis encontra-se concentrada em uma camada de 0,5 m no mesmo sítio, incluindo um novo saurópodo titanossaurídeo, Futalognkosaurus dukei n. gen, n. sp., que é o mais completo dinossauro gigante encontrado até a presente data. Foram descobertas váriasfolhas de plantas indicando a predominância de angiospermas sobre gimnospermas que possivelmente formavam a base da dieta de F. dukei. Outros dinossauros (saurópodes, terópodes, ornitópodes), crocodilomorfos, pterossauros e peixes foram também encontrados possibilitando a reconstrução parcialdeste ecossistema continental do Gondwana.

A unique site at the northern area of Patagonia (Neuquén, Argentina) reveals a terrestrial ecosystem preserved in a detail never reported before in a Late Cretaceous deposit. An extraordinary diversity and abundance of fossils was found concentrated in a 0.5 m horizon in the same quarry, including a new titanosaur sauropod, Futalognkosaurus dukei n.gen., n.sp, which is the most complete giant dinosaur known so far. Several plant leaves, showing a predominance of angiosperms over gymnosperms that likely constituted the diet of F. dukei were found too. Other dinosaurs (sauropods, theropods, ornithopods), crocodylomorphs, pterosaurs, and fishes were also discovered, allowing a partial reconstruction of this Gondwanan continental ecosystem.

O registro fóssil de elementos cranianos de titanossaurídeos é escasso, sendo que nenhum crânio completo foi descrito até o momento. Neste trabalho descrevemos um novo basicrânio (MUCPv-334) procedente de camadas avermelhadas do Subgrupo Rio Colorado (CretáceoSuperior) que afloram na região Bajo del Añelo, situada aproximadamente a 20 km norte da cidade Añelo (Província de Neuquén, Argentina). A presença de processos do basipterigoide direcionados ventralmente sugere que este exemplar represente um Titanosauridae. A robustez do basicrânio aliada à extensa crista proótica e a presença de uma prolongação do parasphenoide chegando até os basal tubera nunca tinham sido reportados em outros Titanosauridae, indicando que este clado de saurópodes possuía uma diversidade maior na morfologia do basicrânio do que se supunha.

The fossil record of cranial material from titanosaurid sauropods is very poor and no complete skull has been described so far. Here we describe a new braincase (MUCPv-334) that was recovered from reddish sandstones of the Rio Colorado Subgroup (Late Cretaceous) of the region of Bajo del Añelo, approximately 20 km north of the town Añelo (Neuquén Province, Argentina). This specimen is attributed to the Titanosauridae based on the ventrally projected basipterygoid processes, a common condition shared by other titanosaurids. The robustness of MUCPv-334 together with an unusually expanded crista prootica and the presence of an anterior prolongation of the parasphenoid reaching the basal tubera were not reported in other members of the Titanosauridae, indicating a larger diversity in the braincase morphology of this sauropod clade than previously thought.

Rinconsaurus caudamirus gen. et sp. nov. (Dinosauria, Sauropoda) is a new and slender Titanosauridae. The specimens come from the Upper Cretaceous strata of the Río Neuquén Formation at Rincón de los Sauces, Neuquén Province, Patagonia, Argentina. The remains include 13 articulated caudal vertebrae and disarticulated cranial, cervical, dorsal and appendicular materials. These fossils belong to three individuals, two adults and one juvenile. This new species is characterized by the following association of autapomorphies: (1) neural spines in mid-anterior dorsal vertebrae inclined posteriorly more than 60 degrees with respect to the vertical, (2) middle caudal vertebrae with bony processes that support the articular surfaces of postzygapophyses, and (3) procoelous posterior caudal centra with intercalation of a series of amphicoelous-biconvex or amphicoelous-opisthocoelous-biconvex centra. A cladistic phylogenetic analysis placed Rinconsaurus in the family Titanosauridae. Within Titanosauridae (Rinconsaurus + Aeolosaurus) is considered a sister group of the clade (Opisthocoelicaudia + (Alamosaurus + (Neuquensaurus + Saltasaurus))). Rinconsaurus caudamirus has preserved short articulated posterior caudal series with amphicoelous, opisthocoelous and biconvex centra. This unusual morphology represents the first such occurrence in sauropod dinosaurs. From the systematic point of view, this discovery is important because Titanosauridae were traditionally defined, among other characters, by strongly developed procoelia in their caudal vertebrae

Rinconsaurus caudamirus gen. et sp. nov., un nuevo titanosáurido (Dinosauria, Sauropoda) del Cretácico Tardío de Patagonia, Argentina. Rinconsaurus caudamirus gen et sp. nov. (Dinosauria, Saurpoda) es un nuevo y esbelto Titanosauridae proveniente de la Formación Río Neuquén, Cretácico Superior de Rincón de los Sauces, Provincia de Neuquén, Patagonia, Argentina. Sus restos están integrados por 13 vértebras caudales articuladas y materiales craneales, cervicales, dorsales y apendiculares desarticulados, que pertenecen a tres individuos, dos adultos y un juvenil. Este nuevo taxón se caracteriza por la siguiente asociación de autapomorfías: (1) vértebras dorsales medioanteriores con espinas neurales inclinadas posteriormente más de 60 grados con respecto a la vertical, (2) vértebras caudales medias con procesos óseos que sostienen las carillas articulares de las poszigapófisis y (3) vértebras caudales procélicas con intercalaciones de series con centros anficélicos y bioconvexos, o con centros anficélicos, opistocélicos y biconvexos. Un análisis filogenético cladista permite incluir a Rinconsaurus en la familia Titanosauridae. Dentro de Titanosauridae (Rinconsaurus +Aeolosaurus) es considerado un grupo hermano del clado (Opisthocoelicaudia + (Alamosaurus + (Neuquensaurus + Saltasaurus))). Rinconsaurus caudamirus presenta dos cortas secuencias caudales posteriores articuladas con centros anficélicos, opistocélicos y biconvexos. Esta inusual morfología se registra por primera vez en dinosaurios saurópodos. Es importante desde el punto de vista sistemático, ya que Titanosauridae ha sido tradicionalmente definido, entre otros caracteres, por la presencia de fuerte procelia en sus vértebras caudales