Federico A. Gianechini

National Scientific and Technical Research Council | conicet · IMIBIO / SL Instituto Multidisciplinario de Investigaciones Biológicas de San Luis

Here we provide a detailed description of the postcranial skeleton of the holotype and referred specimens of Buitreraptor gonzalezorum . This taxon was recovered as an unenlagiine dromaeosaurid in several recent phylogenetic studies and is the best represented Gondwanan dromaeosaurid discovered to date. It was preliminarily described in a brief art...

Abelisaurids are among the most abundant and diverse Patagonian Late Cretaceous theropods. Here, we present a new furileusaurian abelisaurid, Llukalkan aliocranianus gen. et sp. nov., represented by cranial remains from the Bajo de la Carpa Formation (Santonian) at La Invernada fossil area, northwestern Patagonia. Features characterizing this taxon...

Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by highly reduced forelimbs that stand in contrast to their huge dimensions, massive skulls, and obligate bipedalism.¹,² Another group that follows this pattern, yet is still poorly known, is the Carcharodontosauridae: dominant predators that inhabited most con...

Soft tissue reconstructions of fossil vertebrates provide valuable data and support for functional interpretations. Here, we present the pelvic and hindlimb muscular reconstruction of Buitreraptor gonzalezorum, a unenlagiine dromaeosaurid theropod. Dromaeosaurids employed their hindlimbs for locomotion and predation, with a specialised pedal digit...

A new titanosaur sauropod genus including an almost complete skull and axial elements to the hips, reflecting a convergent bauplan with the older rebbachisaurids sauropods.

The Alvarezsauridae comprises a group of enigmatic maniraptoran theropods from the Upper Cretaceous of South America, North America, Europe, and Asia. Among their most distinctive features are their short, robust forelimbs, and manus with an enlarged digit I bearing a massive claw and lateral digits highly reduced or absent. Among the Gondwanan alv...

A new specimen, MAU-Pv-PH-453, comprising an isolated femur from the Plottier Formation (Coniacian-Santonian), northern Patagonia, is described here. Its characteristics, i.e., an anteriorly curved diaphysis; fused lesser and greater trochanters forming a trochanteric crest; a prominent medially directed head; and the absence of a fourth trochanter...

Alvarezsauroidea is a specialized clade of theropods with a complicated taxonomic history. Originally interpreted as flightless stem birds, their phylogenetic position within Maniraptoriformes is debated, and they are the only theropod lineage besides birds to exhibit evolutionary miniaturization. In addition to small body size (< 5 kg), late diver...

Unenlagiine paravians are among the most relevant Gondwanan theropod dinosaur clades for understanding the origin of birds, yet their fossil record remains incomplete, with most taxa being represented by fragmentary material and/or separated by lengthy temporal gaps, frustrating attempts to characterize unenlagiine evolution. Here we describe Diuqi...

The study of thirty-two shed crowns from the Portezuelo Formation (middle Turonian-late Coniacian) at the Sierra del Portezuelo locality, reveals six distinct tooth morphotypes identified through cladistic, discriminant, and cluster analyses. Two morphotypes were identified as belonging to Megaraptoridae, three to Abelisauridae, one to Abelisauroid...

The study of thirty-two shed crowns from the Portezuelo Formation (middle Turonian-late Coniacian) at the Sierra del Portezuelo locality, reveals six distinct tooth morphotypes identified through cladistic, discriminant, and cluster analyses. Two morphotypes were identified as belonging to Megaraptoridae, three to Abelisauridae, one to Abelisauroid...

Geranoaetus melanoleucus is a widely distributed accipitrid across South America. Like other accipitrids, it employs powerful hindlimb muscles to capture and immobilize prey. Whereas previous research has focused predominantly on the grip muscles of diurnal raptorial birds, detailed myological descriptions of the entire hindlimb are lacking. This s...

Resumen: PRIMER REGISTRO DEL NIDO DE ABEJA FÓSIL ELIPSOIDEICHNUS ME-YERI DE ARGENTINA (COLÓN, PROVINCIA DE ENTRE RÍOS). Se presenta el primer registro de la traza fósil Elipsoideichnus meyeri Roselli, 1987, de afloramientos de la cantera Prefectura Naval Argentina, Parque Nacional El Palmar, Colón (provincia de Entre Ríos), Argentina. E. meyeri con...

The Cerro Overo-La Invernada area in north Patagonia has provided a rich record of Cretaceous continental tetrapods in the last two decades, mainly from the Bajo de la Carpa Formation (Upper Cretaceous, Santonian). The dinosaur fauna from this area is diverse, including several new taxa, with abelisaurid theropods particularly abundant. Recently, a...

The diversity of the Upper Cretaceous (Cenomanian to Maastrichtian) crocodyliforms in Argentina is represented by several families of notosuchians (Notosuchidae, Comahuesuchidae, Baurusuchidae, Peirosauridae), and basal mesoeucrocodylian taxa. Most species (such as Neuquensuchus universitas, Notosuchus terrestris, Comahuesuchus brachybuccalis, Cyno...

The abundant record of theropods from Bajo de La Carpa Formation (Neuquén Group, Santonian), known from the end of the nineteenth century, come from numerous locations within the Neuquén Basin. During the excavation of the titanosaur Bonitasaura salgadoi at the La Bonita fossiliferous site, northwest of Río Negro province Argentina, were recovered...

This contribution summarizes the history of paleontology in the Mesozoic sediments of the San Luis Province, as well as historical reviews of how the first activities related to the creation of a museum arise. The first findings in this province were made in the 1940s approximately, with the discovery of dinosaur footprints and later in 1963 the di...

El abundante registro de terópodos de la Formación Bajo de la Carpa (Grupo Neuquén, Santoniano), conocido desde fines del siglo XIX, proviene de numerosas localidades dentro de la Cuenca Neuquina. Durante la excavación del titanosaurio Bonitasaura salgadoi en la localidad de La Bonita, ubicada en las cercanías de Cerro Policía, en el noroeste de la...

Two new specimens of abelisaurid theropods from La Invernada fossil area (Bajo de la Carpa Formation; Santonian) are described. They correspond to an incomplete skull and several postcranial remains. MAU-Pv-LI-582 (skull) shares some morphological traits with other furileusaurs (Viavenator exxoni and Llukalkan aliocranianus) from the same area, as:...

Postcranial skeletal pneumaticity (PSP) characterizes extant birds. This feature is related to a series of air sacs connected to the lungs and prolonged in diverticula that invade bones internally. Previous works revealed that PSP was present along the line to birds, being distinctive of pterosaurs and saurischian dinosaurs. PSP is profuse in the v...

Abelisauridae is a theropod clade with a wide distribution in the Late Cretaceous of Gondwana. Some of the best preserved abelisaurid specimens were recovered from Patagonia (Argentina) such as Skorpiovenator, Ilokelesia, Carnotaurus and Aucasaurus. Here we describe a dorsal part of a neural spine; a middle caudal vertebra; a distal part of a left...

Tetrapod limbs morphology is a reliable proxy of locomotor capacities. Beyond this, other aspects of life habits, such as predation abilities, can also be relevant to determine main morphofunctional appendicular properties, which ultimately reflect a compromise between different factors of the biological role. Dromaeosauridae is a dinosaur clade be...

Megaraptorids constitute a recently recognized new clade of theropod dinosaurs that have been documented in Africa, Oceania, and Asia, although the most abundant record comes from South America and especially from Argentina. Here we report a new megaraptoran specimen (MCNA-PV 3109 to 3117 and 5119 to 5123) recovered from Cañadón Amarillo in out-cro...

Unenlagiinae is mostly recognized as a subclade of dromaeosaurids. They have the modified pedal digit II that characterize all dromeosaurids, which is typically related to predation. However, derived Laurasian dromaeosaurids (eudromaeosaurs) differ from unenlagiines in having a shorter metatarsus and pedal phalanx II-1, and more ginglymoid articula...

Strict consensus of the MPTs obtained from the phylogenetic analysis.

Character list used for phylogenetic analysis.

Selected measurements of the postcranial bones of the holotype and referred specimens of Buitreraptor gonzalezorum.

Here we provide a detailed description of the postcranial skeleton of the holotype and referred specimens of Buitreraptor gonzalezorum . This taxon was recovered as a unenlagiine dromaeosaurid in several recent phylogenetic studies and is the best represented Gondwanan dromaeosaurid discovered to date. It was preliminarily described in a brief arti...

Several remains of an abelisaurid theropod including a nearly complete sacral complex articulated with both ilia, the distal boot of the pubes, the furcula, teeth, and fragments of transverse processes of caudal vertebrae was discovered in the La Invernada fossil site, northern Patagonia from the Bajo de la Carpa Formation (Santonian). The sacrum e...

The complete osteology of the abelisaurid Viavenator exxoni, from the Bajo de la Carpa Formation (Santonian, Upper Cretaceous) is described. Viavenator is characterized by a series of autapomorphies, including: transversely compressed parietal depressions on both sides of the supraoccipital crest; ventral edges of the paraoccipital processes locate...

Buitreraptor gonzalezorum is a theropod dinosaur belonging to the clade Unenlagiidae. It is known by several specimens coming from the Upper Cretaceous of Northwestern Patagonia, Argentina. In spite of its completeness, only a preliminary description of its postcranial anatomy is available. The aim of the present contribution is to make a detailed...

Buitreraptor gonzalezorum is a paravian theropod from the Late Cretaceous of Patagonia that has been recovered as an unenlagiine dromaeosaurid in several phylogenies. It was preliminarily described in a brief article, but a detailed osteology has not been published to date. Here we provide a thorough osteological description of the skull of the hol...

Here, we describe new theropod materials (several isolated teeth, an axis, two caudal centra and a proximal left tibia) from the type locality of the Bajada Colorada Formation (Lower Cretaceous, Berriasian–Valanginian). Although fragmentary, the recovered material shows a diverse association of meat-eating dinosaurs for this poorly understood perio...

The records of Argentine pterosaurs have lately increased notably, both in number of localities and temporal range. New findings come from Late Triassic, Middle and Late Jurassic, and Cretaceous levels. The Late Triassic record is the oldest from Gondwana so far, whereas those of the Jurassic complement the scarce record from this period worldwide....

The braincase anatomy of pterosaurs is poorly known because this region of the skull is rarely preserved, particularly in basal pterodactyloid pterosaurs (Archaeopterodactyloidea). We present new information on the braincase morphology of the Early Cretaceous Argentinean ctenochasmatid Pterodaustro guinazui. Morphological information collected from...

Here we present archosauriform remains from ‘Abra de los Colorados’, a fossiliferous locality at Sierra de Guayaguas, NW San Luis Province. Two fossiliferous levels were identified in outcrops of the Quebrada del Barro Formation (Norian), which represent the southernmost outcrops of the Marayes–El Carrizal Basin. These levels are composed by massiv...

In this contribution, we present tetrapod remains from the Quebrada del Barro Formation, south of Sierra de Guayaguas, NW of San Luis Province. The locality was previously reported but a detailed study of the material is conducted here. The specimens were found isolated, and consist in one partial incomplete maxilla (MIC-V718), one caudal vertebra...

The ichnological record provides valuable information on the lifestyle, behaviour, and other palaeobiological and palaeoecological aspects of the biota. Here, we describe an interesting case of bioerosion trace fossils in bones of Buitreraptor gonzalezorum Makovicky, Apesteguía and Agnolín, 2005, a deinonychosaurian theropod from the fossiliferous...

A new coelurosaurian theropod, Alnashetri cerropoliciensis, is reported here based on articulated hind limbs of a single individual discovered at the locality of La Buitrera (Candeleros Formation, Cenomanian–Turonian), Rı´o Negro Province, Argentina. The new taxon differs from other coelurosaurs in the possession of a low ridge that separates the r...

Over the past two decades, the record of South American unenlagiine dromaeosaurids was substantially increased both in quantity as well as in quality of specimens. Here is presented a summary review of the South American record for these theropods.Unenlagia comahuensis, Unenlagia paynemili, and Neuquenraptor argentinus come from the Portezuelo Form...

The tetrapod assemblage of the Bajo de la Carpa Formation (Late Cretaceous; Santonian-early Campanian) is dominated by archosaurs, represented by saurischians, such as alvarezsaurid, enanthiornithine, and abelisauroid theropods (e.g. Velocisaurus unicus Bonaparte, 1991) and titanosaurs (e.g. Bonitasaura salgadoi Apesteguía, 2004), as well as crocod...

The Unenlagiinae is a clade of Gondwanan dromaeosaurid theropods mainly known from incomplete skeletal material. The group includes two recently discovered theropods, Buitreraptor and Austroraptor, from which cranial remains are available with in situ maxillary and dentary teeth, thus allowing the study of tooth morphology. Among the derived traits...

Gong and colleagues recently described unusual traits in the dromaeosaurid Sinornithosaurus that were interpreted as the first evidence of a venomous dinosaur. This interpretation was based on extremely elongated maxillary teeth, morphologically similar to those present in poisonous snakes; labial grooves on maxillary and dentary tooth crowns; and...