Matteo Fabbri

Field Museum of Natural History

Body size and body mass can give important hints on the ecology, behaviour, physiology and biomechanics of extinct organisms (e.g., Romano et al., 2023). Therefore, applying methods for obtaining precise and reliable estimates is essential. This is particularly true for tetrapods with unique anatomical blueprints and no modern-day ecological and mo...

The hylaeochampsid crocodylomorph Acynodon adriaticus, from the uppermost Cretaceous ‘Villaggio del Pescatore’ site, belongs to an early diverging lineage in Eusuchia. Here an additional specimen, MCSNT 57031, is osteologically and osteohistologically described in detail. After integrating this morphological information together with the recent chr...

Understanding the evolution of the tetrapod brain is essential to trace the history of ecomorphological diversification of modern clades. While previous studies focused on the morphological transformation of the nervous system along the dinosaur–bird transition, little is known about the brain anatomy of archosauriformes and early archosaurs. Here,...

While evolvability of genes and traits may promote specialization during species diversification, how ecology subsequently restricts such variation remains unclear. Chemosensation requires animals to decipher a complex chemical background to locate fitness‐related resources, and thus the underlying genomic architecture and morphology must cope with...

Birds and mammals independently evolved the highest metabolic rates among living animals¹. Their metabolism generates heat that enables active thermoregulation¹, shaping the ecological niches they can occupy and their adaptability to environmental change². The metabolic performance of birds, which exceeds that of mammals, is thought to have evolved...

Myhrvold et al. suggest that our inference of subaqueous foraging among spinosaurids is undermined by selective bone sampling, inadequate statistical procedures, and use of inaccurate ecological categorizations. Myhrvold et al. ignore major details of our analyses and results, and instead choose to portray our inferences as if they were based on qu...

Living birds (Aves) have bodies dramatically modified from the ancestral reptilian condition. The avian pelvis in particular experienced dramatic changes during the transition from early archosaurs to living birds. This stepwise transformation is well documented by an excellent fossil record; however, the ontogenetic alterations that underly it are...

Secondary aquatic adaptations evolved independently more than 30 times from terrestrial vertebrate ancestors1,2. For decades, non-avian dinosaurs were believed to be an exception to this pattern. Only a few species have been hypothesized to be partly or predominantly aquatic3–11. However, these hypotheses remain controversial12,13, largely owing to...

Eudromaeosauria is a clade of derived dromaeosaurids that typifies the common perception of ‘raptor’ dinosaurs. The evolutionary history of this clade has been controversial due to conflicting views of taxonomic identity, and because, due to taphonomic bias, several species were diagnosed primarily or solely by the maxilla. The maxilla is therefore...

During the latest Cretaceous, the European Archipelago was characterized by highly fragmented landmasses hosting putative dwarfed, insular dinosaurs, claimed as fossil evidence of the “island rule”. The Villaggio del Pescatore quarry (north-eastern Italy) stands as the most informative locality within the palaeo-Mediterranean region and represents...

While evolvability of genes and traits may promote specialization during species diversification, how ecology subsequently restricts such variation remains unclear. Chemosensation requires animals to decipher a complex chemical background to locate fitness-related resources, and thus the underlying genomic architecture and morphology must cope with...

The Late Cretaceous Mediterranean archipelago, its geodynamic history, ecological diversity, paleogeography and faunal composition stand as one of the most complex and debated topics related to the evolution of the Tethys Ocean and its continental margins. We conducted a pilot project started in 2019, generating novel and unforeseen outcomes relate...

The latest Cretaceous Adriatic Carbonate Platform (AdCP) system in the paleo-Mediterranean area stands as one of the most complex and debated topics related to the evolution of land vertebrates in the area surrounding the Tethys Sea. Italy holds the sole Late Cretaceous dinosaur-dominated site of the AdCP, namely the Villaggio del Pescatore localit...

Evolutionary variation in ontogeny played a central role in the origin of the avian skull. However, its influence in subsequent bird evolution is largely unexplored. We assess the links between ontogenetic and evolutionary variation of skull morphology in Strisores (nightbirds). Nightbirds span an exceptional range of ecologies, sizes, life-history...

Reduced limbs and limblessness have evolved independently in many lizard clades. Scincidae exhibit a wide range of limb‐reduced morphologies, but only some species have been used to study the embryology of limb reduction (e.g., digit reduction in Chalcides and limb reduction in Scelotes). The genus Brachymeles, a Southeast Asian clade of skinks, in...

Sauropod dinosaurs include the largest terrestrial vertebrates that have ever lived. Virtually every part of the sauropod body is heavily modified in association with gigantic size and associated physiological alterations. Sauropod skulls are no exception: they feature elongated, telescoped facial regions connected to tilted neurocrania and reorien...

Reduced limbs and limblessness have evolved independently in many lizard clades. Skinks exhibit a wide range of limb-reduced morphologies, but only some species have been used to study the embryology of limb reduction (i.g., digit reduction in Chalcides and limb reduction in Scelotes ). The genus Brachymeles , a Southeast Asian clade of skinks, inc...

Chemosensation is the most ubiquitous sense in animals, enacted by the products of complex gene families that detect environmental chemical cues and larger-scale sensory structures that process these cues. While there is a general conception that olfactory receptor (OR) genes evolve rapidly, the universality of this phenomenon across vertebrates, a...

Calcified eggshells protect developing embryos against environmental stress and contribute to reproductive success¹. As modern crocodilians and birds lay hard-shelled eggs, this eggshell type has been inferred for non-avian dinosaurs. Known dinosaur eggshells are characterized by an innermost membrane, an overlying protein matrix containing calcite...

In recent decades, intensive research on non-avian dinosaurs has strongly suggested that these animals were restricted to terrestrial environments¹. Historical proposals that some groups, such as sauropods and hadrosaurs, lived in aquatic environments2,3 were abandoned decades ago4–6. It has recently been argued that at least some of the spinosauri...

The most commonly preserved soft tissues associated with ornithischian dinosaurs are skin remains. The apparent resistance of hadrosaur skin to decay, and its abundance in the fossil record relative to that of other tetrapods, has been attributed to factors such as thickness and composition. Here we report additional intrinsic factors within hadros...

Vertebrate hard tissues consist of mineral crystallites within a proteinaceous scaffold that normally degrades post-mortem. Here we show, however, that decalcification of Mesozoic hard tissues preserved in oxidative settings releases brownish stained extracellular matrix, cells, blood vessels, and nerve projections. Raman Microspectroscopy shows th...

Spinosaurinae are known to have a strong relationship with aquatic environments, involving several anatomical adaptations. Nonetheless, this group of theropods remains enigmatic, due to the relative incompleteness of its fossil record. A large partial tibia from the Aptian-Albian Romualdo Formation, Northeast Brazil, is herein described through ana...

Spinosaurinae are known to have a strong relationship with aquatic environments, involving several anatomical adaptations. Nonetheless, this group of theropods remains enigmatic, due to the relative incompleteness of its fossil record. A large partial tibia from the Aptian-Albian Romualdo Formation, Northeast Brazil, is herein described through ana...

Abstract - MSNM V345 is a partial skeleton of the North American hadrosaur species Gryposaurus notabilis, Lambe 1914, discovered in 1922 in the Dinosaur Park Formation of Dinosaur Provincial Park, Alberta, Canada. It was shipped in several crates to the Museo di Storia Naturale di Milano (MSNM), Italy, where it arrived in October 1958. Careless tra...

Major transformations in brain size and proportions, such as the enlargement of the brain during the evolution of birds, are accompanied by profound modifications to the skull roof. However, the hypothesis of concerted evolution of shape between brain and skull roof over major phylogenetic transitions, and in particular of an ontogenetic relationsh...

Ouranosaurus nigeriensis is an iconic African dinosaur taxon that has been described on the basis of two nearly complete skeletons from the Lower Cretaceous Gadoufaoua locality of the Ténéré desert in Niger. The entire holotype and a few bones attributed to the paratype formed the basis of the original description by Taquet (1976). A mounted skelet...

Supplementary information on measurements, field maps and phylogenetic analysis

Many recent studies using next generation technologies to unravel exceptional molecular preservation have changed our view on the limits of biomolecular stability during fossilization. Nevertheless, common hard tissues have not attracted much attention. Thus, the color change of vertebrate hard tissues from in vivo white to blackish-brown in many f...

The avian skull is distinctive in its construction and in its function. Much of bird anatomical variety is expressed in the beak; but the beak itself, largely formed of the premaxillary bone, is set upon a shortened face and a bulbous, enlarged braincase. Here, we use original anatomical observations and reconstructions to describe the overall form...

A well preserved middle caudal vertebra from middle Cretaceous (?Albian–lower Cenomanian) deposits informally known as the “Kem Kem beds” exposed in the Gara Sbaa region of Morocco is attributed to a large-bodied titanosaurian sauropod dinosaur. It represents one of the best-preserved and most complete skeletal elements reported for this sauropod g...

Discovered over a century ago in Cretaceous rocks in Egypt, Spinosaurus aegyptiacus has remained an enigma, as all of the original associated bones were destroyed in a WW2 air raid and all that has come to light since are isolated specimens. In 2008, a partial skeleton was discovered by local collectors from the lower unit of the mid-Cretaceous Kem...

The specimen MSNM V345, a nearly complete skeleton of Gryposaurus notabilis from the Dinosaur Park Formation, Alberta, Canada, arrived at the Museo di Storia Naturale di Milano (MSNM) in 1958, after an exchange of paleontological specimens with the Field Museum of Chicago. A preliminary study of the fossil was conducted while part of it was still u...

We describe adaptations for a semiaquatic lifestyle in the dinosaur Spinosaurus aegyptiacus. These adaptations include retraction of the fleshy nostrils to a position near the mid-region of the skull and an elongate neck and trunk that shift the center of body mass anterior to the knee joint. Unlike terrestrial theropods, the pelvic girdle is downs...

Preparation of the holotype specimen of Bobosaurus forojuliensis, a large sauropterygian from the lower Carnian of northeastern Italy, revealed new morphological data relevant in establishing its phylogenetic affinities among pistosauroid taxa and its relationships with plesiosaurians. Inclusion of B. forojuliensis in two phylogenetic analyses focu...

In this study, we erect Sauroniops pachytholus gen. et sp. nov., a large-bodied theropod dinosaur from the Cenomanian (Upper Cretaceous) of Morocco, on the basis of an almost complete frontal showing a unique combination of features including a naso-frontal suture extended along 40% of the frontal length, a thick dome in the anterolateral corner of...

We report an isolated frontal of a large-bodied theropod from the Cenomanian “Kern Kern beds” of Morocco with an unusual morphology that we refer to a new carcharodontosaurid distinct from the sympatric Carcharodontosaurus. The specimen shows an unique combination of plesiomorphic and potentially autapomorphic features: very thick and broad bone wi...