Agustin G. Martinelli

Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" · Seccion Paleontologia de Vertebrados

We summarize here the Late Cretaceous vertebrate record of the Triângulo Mineiro (western portion of the Minas Gerais State, southeastern Brazil). All the specimens come from the Bauru Group (Bauru Basin) from the Adamantina (Campanian), Uberaba (Campanian) and Marília (Maastrichtian) formations. Vertebrate-bearing sites are distributed throughout...

We describe two new cynodonts from the early Late Triassic of southern Brazil. One taxon, Bonacynodon schultzi gen. et sp. nov., comes from the lower Carnian Dinodontosaurus AZ, being correlated with the faunal association at the upper half of the lower member of the Chañares Formation (Ischigualasto-Villa Unión Basin, Argentina). Phylogenetically,...

The fossil record of non-mammaliaform probainognathian cynodonts is outstanding in the Late Triassic rocks of Brazil and Argentina. Approximately 15 genera are known, providing unique insights in the study of the major skeletal transformations prior to the mammalian condition. Globally, the diversity of probainognathians is possibly under-represent...

In this contribution we report the first occurrence of the enigmatic African probainognathian genus Aleodon in the Middle-early Late Triassic of several localities from the state of Rio Grande do Sul in southern Brazil. Aleodon is unusual among early probainognathians in having transversely-expanded postcanine teeth, similar to those of gomphodont...

In the last decades, several discoveries have uncovered the complexity of mammalian evolution during the Mesozoic Era, including important Gondwanan lineages: the australosphenidans, gondwanatherians, and meridiolestidans (Dryolestoidea). Most often, their presence and diversity is documented by isolated teeth and jaws. Here, we describe a new meri...

Hasta recientemente, la principal fuente de información sobre mamíferos mesozoicos sudamericanos provenía de la Patagonia argentina, con numerosas especies de mamíferos no-Theria, incluidos en los clados Gondwanatheria/Allotheria, Meridiolestida y Driolestidae. Sin embargo, hallazgos recientes en rocas del Cretácico Superior de la Formación Dorotea...

The description of new titanosaur specimens unearthed from deposits of the Serra da Galga Formation (Bauru Group, Late Cretaceous) at the BR-262 site, near Peirópolis (Uberaba, Minas Gerais State, Brazil), sheds light on the taxonomy of two taxa previously known from the same area and geological unit: Baurutitan britoi and Trigonosaurus pricei. A c...

The Lohan Cura Formation (Albian) at the Cerro de los Leones locality (Neuquén Province, Patagonia, Argentina) yielded several fossil materials, especially sauropod specimens. Among these, Agustinia ligabuei includes postcranial elements of a single individual, with widely debated taxonomy and phylogeny. Here, we provide an extended osteological de...

Two lineages of Kannemeyeriiformes (Synapsida, Dicynodontia) are currently known in the Ladinian-Carnian Chañares Formation (Ischigualasto-Villa Unión Basin, Argentina): stahleckeriine stahleckeriids, based upon postcrania, and a single non-stahleckeriine species, Dinodontosaurus brevirostris, known mostly by cranial material. Available data on the...

Las asociaciones de vertebrados del Cretácico Superior en altas latitudes de Sudamérica son relevantes para el entendimiento de la evolución y paleobiogeografía de las biotas australes. En particular, los afloramientos de la Formación Dorotea en el Valle del río de Las Chinas, ubicado en la Región de Magallanes, preservan un extenso registro geológ...

Among terrestrial vertebrates, only crown birds (Neornithes) rival mammals in terms of relative brain size and behavioural complexity. Relatedly, the anatomy of the avian central nervous system and associated sensory structures, such as the vestibular system of the inner ear, are highly modified with respect to those of other extant reptile lineage...

Endothermy underpins the ecological dominance of mammals and birds in diverse environmental settings1,2. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most of the fossil evidence is ambiguous3–17. Here we show that this key evolutionary transition can be investigated using the morphology of the e...

In this contribution we compile, still preliminarily, information on Santiago Pozzi (1849-1929), son of Antonio (1822-1898), who made immense contributions to natural and anthropological sciences as part of his work as a technician at the Argentinean National Museum and the Museo de La Plata, being a tireless assistant and companion in fieldwork ta...

Elio Massoia (1936-2001) se interesó desde joven por las ciencias naturales y rápidamente descubrió en los mamíferos, y especialmente entre los roedores, un campo de investigación casi ilimitado. Durante su vida Massoia generó más de 250 trabajos publicados y editó una revista de comunicaciones científicas de elaboración muy artesanal que se convir...

PALEOHERPETOLOGY IN THE MIGUEL LILLO INSTITUTE OF THE NATIONAL UNIVERSITY OF TUCUMAN, ARGENTINA. The Vertebrate Fossil Laboratory (LVF) of the Miguel Lillo Institute at the National University of Tucuman started in 1957 with the initial drive of Osvaldo Reig, who was its first Director and Curator of the Lillo Vertebrate Paleontology (PVL) collecti...

Titanosaurs were successful herbivorous dinosaurs widely distributed in all continents during the Cretaceous, with the major diversity in South America. The success of titanosaurs was probably due to several physiological and ecological factors, in addition to a series of morphological traits they achieved during their evolutionary history. However...

Osteological knowledge of the sauropod dinosaur Ligabuesaurus leanzai is increased by the description of new postcranial elements assigned to the holotype MCF-PVPH-233. Furthermore, a newly referred specimen, MCF-PVPH-228, is recognized after a detailed revision of the abundant sauropod material collected from the Lohan Cura Formation outcrops in t...

We describe the fossil content of the Carolina Soil outcrop in Vera Cruz Municipality (Rio Grande do Sul State, Brazil), which represents one of the few localities with a conspicuous fossil record in the still poorly sampled Upper Triassic Santacruzodon Assemblage Zone (Santa Cruz Sequence, Santa Maria Supersequence). The site has yielded numerous...

Notosuchia is a highly diverse group of crocodyliforms that peaked during the Cretaceous period. Their taxonomic abundance and morphological disparity in the Upper Cretaceous Bauru Group (Bauru Basin, Brazil) is remarkable, with over 20 species reported. The stable carbon and oxygen isotope composition of notosuchian bioapatite from two sites (i.e....

The fossil record of the genus Bothrops is still sparse in South America. Most records belong to extant species recovered in strata not older than the late Pleistocene. The genus was also tentatively reported from the early Pliocene and earlymiddle Pleistocene of Buenos Aires province, Argentina, based on fragmentary specimens. The aim of the prese...

Irajatherium hernandezi is a poorly known non‐mammaliaform cynodont from the Late Triassic of southern Brazil. A new specimen of this cynodont was found in recent fieldwork to the type‐locality, the Linha São Luiz site (Candelária Sequence), providing new insights into the anatomy of this mammalian forerunner. The new specimen comprises a partial s...

Rhynchocephalians are a group of lizard-like diapsid reptiles that were very diverse during the Mesozoic but are now restricted to a single extant genus in New Zealand. Recent cladistic analyses have revealed two major clades, Eusphenodontia and the more crownward Neosphenodontia, but relationships of individual taxa have remained difficult to dete...

Hasta recientemente, la principal fuente de información sobre mamíferos mesozoicos sudamericanos provenía de la Patagonia argentina, con numerosas especies de mamíferos no-Theria, incluidos en los clados Gondwanatheria/Allotheria, Meridiolestida y Driolestidae. Sin embargo, hallazgos recientes en rocas del Cretácico Superior de la Formación Dorotea...

Polyphyodonty—multiple tooth generations—in Mesozoic birds has been confirmed since the nineteenth century. Their dental cycle had been assessed through sparse data from tooth roots revealed through broken jawbones and disattached teeth. However, detailed descriptions of their tooth cycling are lacking, and the specifics of their replacement patter...

Here we present, for the first time, the use of finite element analysis to evaluate bites of two possible predators, a baurusuchid crocodyliform and an abelisaurid theropod into titanosaur osteoderms, in order to test if these structures could act as defensive tools. Our results showed that bites caused much less stress on osteoderms that did not w...

The Late Cretaceous Marília Formation (Bauru Group, Bauru Basin) is a geological unit that occurs on São Paulo, Minas Gerais, Goiás, and Mato Grosso do Sul states, Brazil. This formation consists predominantly of paleosols developed in a semiarid/arid environment and recent reappraisal of its formerly known members reduced its lithological composit...

We present a new record of amiid fish discovered during field works carried out in 2019-2020 in rocks of the Upper Cretaceous Araçatuba Formation, Western São Paulo State, southeastern Brazil. Although the fish fauna of the Bauru Group is still poorly known, mainly based on isolated remains, the discoveries of amiid remains (including the one here...

Notosuchians are the most diverse group and are frequently found in rocks of the Upper Cretaceous Bauru Group of southeastern Brazil. These crocodyliforms occupied several different terrestrial ecological niches, ranging from small to large bodied forms, including hypercarnivore to strictly herbivore animals. Most of this diversity comes from the A...

The record of Cretaceous terrestrial lizards (Squamata) in South America is patchy, with seven species described from north-eastern and south-eastern Brazil, and few isolated records of iguanians and scincomorphans from the Argentinian Patagonia. Herein we describe a new genus and species of Cretaceous lizard, Paleochelco occultato gen. et sp. nov....

Los mamíferos de la Era Mesozoica y los sobrevivientes a la extinción que marcó el final del Cretácico ilustran una compleja y antigua historia evolutiva en América del Sur

In: Libro de Resúmenes, 34º JORNADAS ARGENTINAS DE PALEONTOLOGÍA DE VERTEBRADOS

Endothermy (“warm-bloodedness”) underpins the ecological dominance of mammals and birds in diverse environmental settings1-3. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most fossil evidence is ambiguous4-25. Here, we show that new information on this key evolutionary transition can be obtained...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The deposits corresponding to the Upper Cretaceous Neuquén and San Jorge Gulf basins from northern and central Patagonia have provided two of the most complete sequences of terrestrial vertebrate faunas of all Gondwanan landmasses. Among the carnivorous components, the carcharodontosaurid theropods appeared as common elements during the Early Creta...

Aeolosaurus is a late Cretaceous Titanosaur genus with two species discovered in Argentina and one in Brazil. Although the allocation of the Argentinean Aeolosaurus seems unequivocal, that is not the case for the Brazilian species Aeolosaurus maximus since several authors questioned its positioning into this genus, based on both anatomical and phyl...

Triassic beds from Argentina and Brazil provide the most relevant fossil record of early dinosauriforms in terms of numerical abundance and taxonomic diversity. This record currently represents the best source to understand the origin and early evolutionary radiation of dinosaurs. In the present paper we offer an updated review focused on the avail...

Understanding the ontogeny of a taxon is a crucial step to properly elucidate its taxonomy and evolution. However, aside from histological data, osteological criteria for assessing maturity are considered lineage specific or controversial. The sequence of neurocentral suture closure of the axial skeleton of extant crocodilians, which occurs in a po...

Traversodontidae is a group of Triassic herbivorous/omnivorous cynodonts that represents the most diversified lineage within Cynognathia. In southern Brazil, a rich fossil record of late Middle/mid-Late Triassic cynodonts has been documented, with Exaeretodon riograndensis Abdala, Barberena, and Dornelles, 2002 and Siriusgnathus niemeyerorum Pavana...