Federico J Degrange

National Scientific and Technical Research Council | conicet · CICTERRA - Centro de Investigaciones en Ciencias de la Tierra

Brain morphology has become a key element to predict a wide array of cognitive and behavioral, sensory and motor abilities, and to determine evolutionary rates of phenotypic transformation. Our information on early bird brain morphology comes of natural endocasts or studies of the intracranial cavity. Although the first studies of fossil bird brain...

To study the hindlimb connectivity patterns of aquatic birds, we compared the musculoskeletal multi-networks of non-divers (Numididae and Anatidae), wing-propelled divers (Alcidae and Sphenicidae), and foot-propelled divers (Anhingidae, Phalacrocoracidae, Podicipedidae, and Gaviidae). Anatomical multi-networks are undirected multigraphs where bones...

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...

To study morphological evolution, it is necessary to combine information from multiple intersecting research fields. Here, we report on the structure of the bony and muscular elements of the craniomandibular complex of birds, highlighting its morphological architecture and complexity (or simplification) in the context of anatomical networks of the...

en Few investigators have examined in vivo bite-force of birds, likely due, at least in part, to the difficulty in accessing suitable force transducers. We describe a low-cost, easy-to-build, and portable force transducer with the goal of encouraging ornithologists to improve our knowledge of in vivo bite forces of birds. We used a commercial piezo...

We describe a new species of a large buzzard (Accipitridae), Buteo dondasi sp. nov. from the late Pliocene of Buenos Aires Province, Argentina represented by an incomplete left hind limb, including a distal fragment of tibiotarsus, tarsometatarsus, fragment of os metatarsale I, and toes I and II. The new taxon exhibits characteristics of the crown...

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...

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...

The fossil bird Dryornis pampeanus Moreno & Mercerat, is reinterpreted after examination of new referred material (humerus, coracoid, fragments of ulna, radius, scapula, sternum and tibiotarsus) from the Pliocene Chapadmalal Formation of Argentina. The current diagnosis is emended in the light of important considerations that cast doubt on the prev...

We used three‐dimensional digital models to investigate the brain and endosseous labyrinth morphology of selected Neotropical Piciformes (Picidae, Ramphastidae, Galbulidae and Bucconidae). Remarkably, the brain morphology of Galbulidae clearly separates from species of other families. The eminentiae sagittales of Galbulidae and Bucconidae (insectiv...

Phorusrhacidae, popularly known as ‘terror birds’, are the most speciose clade within the avian order Cariamiformes, with a fossil record that ranges from the Eocene to the Pleistocene. Although several species have preserved skulls, our understanding of their cranial morphology remains incomplete. Here, a comprehensive overview of the current know...

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...

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...

We describe new avian remains from the lower levels of the Toro Negro Formation (~7-6 Ma, U–Pb), exposed in Quebrada de la Troya between Vinchina and Jagüé towns in La Rioja Province, Argentina. The Toro Negro Formation is composed of a thick continental sequence (~2.4 km) of sandstones, conglomerates and mudstones deposited in both fluvial and lac...

Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod di...

The giant carnivorous phorusrhacid bird Phorusrhacos longissimus (Aves, Cariamiformes) was first described in 1887 by Florentino Ameghino on the basis of a jaw fragment. The majority of a skull of the species still encased in crumbling rock was preserved only long enough for illustrations to be made by Carlos Ameghino in the field and for a brief d...

A new Anseriformes, Conflicto antarcticus gen. et sp. nov., represented by associated bones of a single individual, from the early Palaeocene of Antarctica is described. The new taxon is unlike any other known member of the order. Conflicto antarcticus is a medium-sized (2 kg) stem anseriform. The forelimb and pectoral girdle bones suggest that it...

A new Anseriformes, Conflicto antarcticus gen. et sp. nov., represented by associated bones of a single individual, from the early Palaeocene of Antarctica is described. The new taxon is unlike any other known member of the order. Conflicto antarcticus is a medium-sized (2 kg) stem anseriform. The forelimb and pectoral girdle bones suggest that it...

Here we address the morphology of the cranial musculoskeletal in the South American Band-winged nightjar (Systellura longirostris, Caprimulgiformes, Aves) with the focus upon in how the mouth closure and opening mechanism is. Bony characters such as the thinness of the interorbital septum and the reduction of the postorbital process co-assist the l...

Madrynornis mirandus, one of the few fossil penguins known from a nearly complete articulated skeleton, represents a key taxon for understanding the stem-crown transition in penguins. Despite the wealth of morphological character data preserved in the holotype specimen, the phylogenetic placement of this early late Miocene taxon has remained contro...

The cranio-mandibular complex is an important structure involved in food capture and processing. Its morphology is related to the nature of the food item. Jaw muscles enable the motion of this complex and their study is essential for functional and evolutionary analysis. The present study compares available behavioral and dietary data obtained from...

[This corrects the article DOI: 10.1098/rsos.170975.].

The extinct dromornithids, gastornithids and phorusrhacids are among the most spectacular birds to have ever lived, with some giants exceeding 500 kg. The affinities and evolution of these and other related extinct birds remain contentious, with previous phylogenetic analyses being affected by widespread convergence and limited taxon sampling. We a...

Supplementary text Document;A complete list of Morphological characters;Data on mass, diet and age of study taxa;3 Apomorphy lists as separate files;Executable files x2

Supplementary text Document;A complete list of Morphological characters;Data on mass, diet and age of study taxa;3 Apomorphy lists as separate files;Executable files x2

Supplementary text Document;A complete list of Morphological characters;Data on mass, diet and age of study taxa;3 Apomorphy lists as separate files;Executable files x2

Supplementary text Document;A complete list of Morphological characters;Data on mass, diet and age of study taxa;3 Apomorphy lists as separate files;Executable files x2

Supplementary text Document;A complete list of Morphological characters;Data on mass, diet and age of study taxa;3 Apomorphy lists as separate files;Executable files x2

The hind limbs of birds have long been considered a key feature in the conquest of different environments. However, the high level of morphological diversity encountered complicates the foundation of a good theoretical correlation between morphology, locomotor habits and substrate preference and this, in turn, complicates palaeobiological interpret...

Se denomina complejo cráneo-mandibular (CCM) al conjunto de estructuras óseas, musculares y nerviosas que ejerce funciones tales como protección (del encéfalo, los órganos sensoriales y de la porción anterior del tracto digestivo y respiratorio) o de conducta (alimentación, construcción de nidos, acicalamiento, defensa, actividades sociales). El cr...

La visualización y análisis de los organismos asistido por computadoras ha revolucionado el estudio de los mismos tanto vivientes como fósiles. Técnicas novedosas permiten caracterizar los restos en tres dimensiones y acceder a detalles sin precedentes. Esto ha permitido ganar importantes conocimientos sobre la anatomía, el desarrollo, la función y...

Penguins have a more than 60 million year long evolutionary history. Thus, stem lineage fossil taxa are key to understanding their evolution. Here, we present data on three virtual endocasts from stem penguin skulls collected from the Eocene La Meseta Formation of Seymour Island (Antarctica), along with comparative data from extant penguins and out...

Psittaciform birds exhibit novelties in jaw bone structure and musculature that are associated with strong bite forces. These features include an ossified arcus suborbitalis and the muscles ethmomandibularis and pseudomasseter. We analyse the jaw musculature of the monk parakeet (Myiopsitta monachus) to enable future studies aimed at understanding...

Psittaciformes are a very diverse group of non-passerine birds, with advanced cognitive abilities and highly developed locomotor and feeding behaviours. Using computed tomography and three-dimensional (3D) visualization software, the endocasts of 14 extant Neotropical parrots were reconstructed, with the aim of analysing, comparing and exploring th...

Psilopterines are the smallest and most gracile predatory birds belonging to the large terrestrial Phorusrhacidae, which were abundant during the South American Tertiary. Two taxa are recognized from the Santacrucian (late Early Miocene) beds of Argentinian Patagonia: Psilopterus lemoinei and Psilopterus bachmanni. Although the first species was re...

Terror birds constitute the most outstanding group of the South American Cenozoic avifauna. Considered as apex predators, their hunting skills have recently been examined, but their diversity is still unresolved. Here we report a new terror bird from the late Pliocene of Argentina, represented by the most complete articulated skeleton of one yet fo...

Visualization and analysis of fossils assisted by computers have revolutionized the study of extinct organisms. Innovative techniques allow to characterize the remains in three dimensions with unprecedented detail, allowing paleontologists to gain important knowledge about anatomy, development, function and even conservation. Digital reconstruction...

Visualization and analysis of fossils assisted by computers have revolutionized the study of extinct organisms. Innovative techniques allow to characterize the remains in three dimensions with unprecedented detail, allowing paleontologists to gain important knowledge about anatomy, development, function and even conservation. Digital reconstruction...

The aim of this contribution is to verify the presence of the suborbital arch and the ethmomandibularis and pseudomasseter muscles in the holotype of Nandayus vorohuensis (Tonni and Noriega, 1996) in order to gain a better understanding of the capabilities of its cranio-mandibular complex and provide new tools for the discussion on the evolution of...

The aim of this work is to describe for the first time the skin and the subcutaneous diverticula at histological level (by light microscopy) of the Southern Screamer Chauna torquata. We found that the main distinguishing features of the skin were the presence of deep and branched epidermal invaginations whereas in the dermis abundant elastic fibers...

Eight adult tarsometatarsi belonging to eight fossil species (Palaeeudyptes gunnari, Palaeeudyptes klekowskii, Anthropornis grandis, Anthropornis nordenskjoeldi, Archaeospheniscus wimani, Marambiornis exilis, Delphinornis arctowskii and Delphinornis larseni) collected from the Antarctic A. nordenskjoeldi Biozone (La Meseta Formation, , 34.2 Ma) wer...

No science is based on complete information, and paleornithology is not the exception. There are several reasons for these gaps in the knowledge. The avian fossil record is certainly incomplete; bird remains constitute a biased data set, the discovery of fossils is not haphazard, and those found reveal only limited information, usually about skelet...

The continental vertebrate collection of the Santa Cruz Formation (Late-early Miocene) is known worldwide by its abundance and diversity. With regard to the bird fossil record, the taxonomical and morphological diversity is also really high. The initial collection was largely made by Carlos Ameghino by the end of the nineteenth century and the rema...

Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress from multidisciplinary analyses encompassing tectonic, isotopic, and radiochemical dating and molecular studies in modern forms. This also changed the k...

Mourasuchus is a Miocene alligatorid endemic to South America, and is represented by four species. Together with the closely related Purussaurus, it is a peculiar crocodylian taxon of neogene Caimaninae and one of the most bizarre forms among eusuchian crocodiles. The phylogenetic relationships between Mourasuchus species have not been explored, an...

Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress from multidisciplinary analyses encompassing tectonic, isotopic, and radiochemical dating and molecular studies in modern forms. This also changed the k...

Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress from multidisciplinary analyses encompassing tectonic, isotopic, and radiochemical dating and molecular studies in modern forms. This also changed the k...

Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress from multidisciplinary analyses encompassing tectonic, isotopic, and radiochemical dating and molecular studies in modern forms. This also changed the k...

Aves remains have been recovered from several continental Cenozoic localities in SSA, mainly in the Pampas and Patagonia in Argentina, Uruguay, and Brazil. We have selected 13 localities because they have the most complete fossil bird associations.

It has been suggested that in South American ecosystems during Cenozoic times, carnivorous birds were hegemonic not only over any other trophic avian guild but also over other vertebrate carnivorous groups (Tambussi 2011 and the literature cited therein). To investigate this, we have chosen to dissect the avian fossil record to determine whether th...

Coastal exposures of the Santa Cruz Formation in southern Patagonia have been a fertile ground for recovery of Early Miocene vertebrates for more than 100 years. This volume presents a comprehensive compilation of important mammalian groups which continue to thrive today. It includes the most recent fossil finds as well as important new interpretat...

Andalgalornis steulleti from the upper Miocene-lower Pliocene (≈6 million years ago) of Argentina is a medium-sized patagornithine phorusrhacid. It was a member of the predominantly South American radiation of 'terror birds' (Phorusrhacidae) that were apex predators throughout much of the Cenozoic. A previous biomechanical study suggests that the s...

The aim of this work is to characterize the growth of the hindlimb muscle mass of the Greater Rhea Rhea americana at different postnatal ages. Twentione muscles were dissected and weighed in 22 specimens of various ages (ranging from a month to full adults) to evaluate their proportion in relation to the body mass and their contribution to the exte...

The aim of this work is to characterize the growth of the hindlimb muscle mass of the Greater Rhea Rhea Americana at different postnatal ages. Twenty- one muscles were dissected and weighed in 22 specimens of various ages (ranging from a month to full adults) to evaluate their proportion in relation to the body mass and their contribution to the ex...

Psilopterus lemoinei, the largest species in this genus, was a small terror bird weighing 8–9 kg, and was a ground bird with functionally tridactyl feet. New remains of this phorusrhacid, including an exceptionally preserved anterior part of a skull recovered from the Patagonian Killik Aike Norte locality (Santa Cruz Formation, late early Miocene),...

A juvenile of Pterocnemia pennata (MACN 14780) from the Bonaerian (early Late Pleistocene) locality of Salto (Salto district), in the north of Buenos Aires Province, Argentina is presented. This is the northernmost record for the species. The specimen consists of the hind limbs and fragments of fore limbs, phalanxes and vertebrae. The aim of this w...

A juvenile of Pterocnemia pennata (MACN 14780) from the Bonaerian (early Late Pleistocene) locality of Salto (Salto district), in the north of Buenos Aires Province, Argentina is presented. This is the northernmost record for the species. The specimen consists of the hind limbs and fragments of fore limbs, phalanxes and vertebrae. The aim of this w...

A juvenile of Pterocnemia pennata (MACN 14780) from the Bonaerian (early Late Pleistocene) locality of Salto (Salto district), in the north of Buenos Aires Province, Argentina is presented. This is the northernmost record for the species. The specimen consists of the hind limbs and fragments of fore limbs, phalanxes and vertebrae. The aim of this w...

Psilopterus lemoinei, the largest species in this genus, was a small terror bird weighing 8–9 kg, and was a ground bird with functionally tridactyl feet. New remains of this phorusrhacid, including an exceptionally preserved anterior part of a skull recovered from the Patagonian Killik Aike Norte locality (Santa Cruz Formation, late early Miocene),...

The Tinamidae comprise exclusively Neotropical palaegnathous birds, with homogeneous body morphology and no sexual dimorphism. The goal of this work was to explore the variation in skull morphology between taxa and its possible correspondence with features such as diet or gender using geometric morphometric tools. Eleven landmarks were analyzed in...

We examined the external anatomy of the endocast of the Greater Rhea (Rhea americana, Palaeognathae), during 3 main stages of its postnatal life, and compared it with information available on other palaeognathous birds. Series of scans with spiral computed tomographies were obtained from 3 skulls of different ages (chick, juvenile and adult) of R....

Skull of Andalgalornis steulleti (FMNH P1435). Left lateral view (volume rendering of CT scan data) with slice planes (A-B) displaying the hollow beak cavity. (3.96 MB TIF)

Log bite force in birds plotted against log body mass. Passeriforms in blue (dark blue: Estrildidae, sky blue: Fringillidae), Rheidae in green, Accipitridae in red, Cathartidae in rose and Cariamidae in black. See Table S1 for raw data. (3.39 MB TIF)

Bite force and body mass table. (0.07 MB DOC)

Andalgalornis' fossil. (0.03 MB DOC)

The South American phorusrhacid bird radiation comprised at least 18 species of small to gigantic terrestrial predators for which there are no close modern analogs. Here we perform functional analyses of the skull of the medium-sized (approximately 40 kg) patagornithine phorusrhacid Andalgalornis steulleti (upper Miocene-lower Pliocene, Andalgalá F...

Tinamous are mainly ground-dwelling birds whose fossil records occur primarily during the Pliocene and Pleistocene from Argentina. In this work, we describe a right coracoids fragment of an indeterminate species of Nothura found in early-middle Pleistocene sediments (Ensenada Formation, Ensenadan) in the Buenos Aires Province. This is the first rec...

Aves fósiles, Tinamidae, Formación Ensenada, Ensenadense, Pleistoceno, Argentina.

The meaning humerus characters in the differentiation of living and fossil penguins of South America and Antarctica was evaluated. Statistical tests, principal components analysis (PCA) and diagrams of logarithmic differences (DLD), were applied to eight decimal variables and four angular values of 192 humerus of 15 species. Patagonian fossil speci...

Evaluation of humerus characters in fossil and living penguins to use them with system-atic purposes. – The meaning humerus characters in the differentiation of living and fossil penguins of South America and Antarctica was evaluated. Statistical tests, principal components analysis (PCA) and diagrams of logarithmic differences (DLD), were applied...