Alfio Alessandro Chiarenza

University College London | UCL · Department of Earth Sciences

A fundamental question in dinosaur evolution is how they adapted to long-term climatic shifts during the Mesozoic and when they developed environmentally independent, avian-style acclimatization, becoming endothermic. The ability of warm-blooded dinosaurs to flourish in harsher environments, including cold, high-latitude regions, raises intriguing...

Significance We present a quantitative test of end-Cretaceous extinction scenarios and how these would have affected dinosaur habitats. Combining climate and ecological modeling tools, we demonstrate a substantial detrimental effect on dinosaur habitats caused by an impact winter scenario triggered by the Chicxulub asteroid. We were not able to obt...

In the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian–Maastrichtian [83–66 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by u...

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...

Past responses to environmental change provide vital baseline data for estimating the potential resilience of extant taxa to future change. Here, we investigate the latitudinal range contraction that terrestrial and freshwater turtles (Testudinata) experienced from the Late Cretaceous to the Paleogene (100.5–23.03 mya) in response to major climatic...

Dinosaurs thrived for over 160 million years in Mesozoic ecosystems, displaying diverse ecological and evolutionary adaptations. Their ecology was shaped by large-scale climatic and biogeographic changes, calling for a ‘deep-time’ macroecological investigation. These factors include temperature fluctuations and the break up of Pangaea, influencing...

Understanding the biospheric response to climate change over evolutionary time scales is a paleontological endeavor. Dinosaurs offer a unique opportunity to examine continuous (>150 million years, Ma) responses to climate in a large clade of terrestrial tetrapods. Throughout the Mesozoic, multiple hyperthermal events influenced diversity, biogeogra...

Dinosaurs potentially originated in the mid-palaeolatitudes of Gondwana 245–235 million years ago (Ma) and may have been restricted to cooler, humid areas by low-latitude arid zones until climatic amelioration made northern dispersals feasible ca 215 Ma. However, this scenario is challenged by new Carnian Laurasian fossils and evidence that even th...

Acynodon adriaticus, a small eusuchian from the Late Cretaceous of Italy, is known for its well‐preserved cranial and postcranial material. Despite its excellent preservation, many details remain hidden due to the physical overlap between the elements and matrix obliteration. We used Micro‐CT scans to reveal previously overlooked anatomical feature...

Collecting data for use in constructing phylogenies is a valuable but time- and resource-consuming pursuit. As a result, indicators of the potential value of including certain species in a phylogeny a priori could prove useful when planning this stage of research. Here, we used a simulation approach to investigate whether there are trends in the ab...

A fundamental question in dinosaur evolution is how they adapted to substantial long-term shifts in Earth System during the Mesozoic and when they developed environmentally independent, avian-style acclimatization due to the evolution of an endothermic physiology. Combining fossil occurrences with macroevolutionary and paleoclimatic models, we unve...

Multiple hypotheses have been proposed to explain the extinction of non-avian dinosaurs, 66 million years ago, with currently two leading contenders: a sudden and catastrophic extinction driven by the impact of an extra-terrestrial body, or a more gradual decline, possibly driven by an extensive period of volcanism. It is now indisputable that an a...

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...

Il clade Dinosauria è un ottimo candidato per lo studio degli effetti del clima sulla macroevoluzione dei vertebrati, avendo attraversato numerosi cambiamenti climatici e paleogeografici sin dalla sua origine, ~235 milioni di anni fa (ma). Per questo studio è stato generato un registro basato su esemplari di tutti i taxa di dinosauri fossili ad ogg...

1. The open-source programming language ‘R' has become a standard tool in the palaeobiologist's toolkit. Its popularity within the palaeobiological community continues to grow, with published articles increasingly citing the usage of R and R packages. However, there are currently a lack of agreed standards for data preparation and available framewo...

It has long been debated why groups such as non-avian dinosaurs became extinct whereas mammals and other lineages survived the Cretaceous/Paleogene mass extinction 66 million years ago. We used Markov networks, ecological niche partitioning, and Earth System models to reconstruct North American food webs and simulate ecospace occupancy before and a...

Dinosauria experienced several episodes of climatic upheavals and palaeogegraphic reconfigurations during their ~150 million years long Mesozoic dominance. These physical changes had a long-term influence on Earth System, making them ideal candidates for investigating the interplay between climate change and evolution. We built a comprehensive data...

1. The open-source programming language ‘R’ has become a standard tool in the palaeobiologist’s toolkit. Its popularity within the palaeobiology community continues to grow, with published articles increasingly citing the usage of R and R packages. However, there are currently a lack of agreed standards for data preparation and available frameworks...

Ecological Niche Models (ENM), the set of different algorithms and workflows designed to obtain hypothetical maps of species, have been broadly used in studies on current biogeography, macroecology and conservation biology. The field experienced hot methodological debates around 10 years ago, when researchers tested the accuracy of the different al...

Ecological niche modelling is applied broadly in ecology to model a species’ niche and map suitable habitat. The approach links species’ occurrences with environmental predictors to statistically derive response curves. Although commonly applied to study extant taxa, ecological niche modelling is an emerging method in palaeobiology, providing oppor...

Paleontological survey in the remote Yukon-Charley Rivers National Preserve in Alaska led to the discovery of lobed Zoophycos from the lower Tahkandit Limestone (informally named Sandstone unit), an interval characterized by grayish-green glauconitic sandstone and conglomerate of coastal origin. The studied Zoophycos consists of a lobate skirt-like...

Dinosaurs dominated Mesozoic terrestrial ecosystems globally. However, whereas a pole-to-pole geographic distribution characterized ornithischians and theropods, sauropods were restricted to lower latitudes. Here, we evaluate the role of climate in shaping these biogeographic patterns through the Jurassic–Cretaceous (201–66 mya), combining dinosaur...

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...

I dinosauri hanno dominato la maggior parte degli habitat terrestri per circa 160 milioni di anni, offrendo così un esempio unico di macroevoluzione in risposta a prolungate e frequenti perturbazioni degli ecosistemi terrestri. Combinando metodi avanzati di modellizzazione paleoclimatica ed ecosistemica, viene dimostrato come: i dinosauri non avian...

Documenting the patterns and potential associated processes of ancient biotas has always been a central challenge in palaeontology. Over recent decades, intense debate has focused on the organization of dinosaur-dominated communities, yet no general consensus has been reached on how these communities were organized in a spatial context. Here, we us...

Compared to the osteological record of herbivorous dinosaurs from the Late Cretaceous Prince Creek Formation of northern Alaska, there are relatively fewer remains of theropods. The theropod record from this unit is mostly comprised of isolated teeth, and the only non-dental remains known can be attributed to the troodontid cf. Troodon and the tyra...

The advent of palaeontological occurrence databases has allowed for detailed reconstruction and analyses of species richness through deep time. While a substantial literature has evolved ensuring that taxa are fairly counted within and between different time periods, how time itself is divided has received less attention. Stage‐level or equal‐inter...

The availability of large-scale occurrence databases has revolutionized palaeobiology, allowing for investigation of diversity and macroecological trends through deep-time. However, the problem of data absence (i.e. does the lack of a fossil occurrence indicate genuine absence or imperfect detection?) has hindered studies, and potentially biased ou...

The archive of fossils and the sedimentary rocks that enclose them preserves a long record of climate change and associated fluctuations of biodiversity. However, this record is biased, and considerable efforts have focused on developing sampling methodologies and statistical treatments to mitigate for bias in a way that will allow us to understand...

The 24 extant crocodylian species are the remnants of a once much more diverse and widespread clade. Crocodylomorpha has an approximately 230 million year evolutionary history, punctuated by a series of radiations and extinctions. However, the group's fossil record is biased. Previous studies have reconstructed temporal patterns in subsampled croco...

Assessments of dinosaur macroevolution at any given time can be biased by the historical publication record. Recent studies have analysed patterns in dinosaur diversity that are based on secular variations in the numbers of published taxa. Many of these have employed a range of approaches that account for changes in the shape of the taxonomic abund...

Assessments of dinosaur macroevolution at any given time can be biased by the historical publication record. Recent studies have analysed patterns in dinosaur diversity that are based on secular variations in the numbers of published taxa. Many of these have employed a range of approaches that account for changes in the shape of the taxonomic abund...

https://gsa.confex.com/gsa/2016AM/webprogram/Paper282955.html

http://svpca.org/years/2016_liverpool/Abstract%20Bookv3.pdf

ABSTRACT: The Kem Kem Compound Assemblage (KKCA) of North Africa has yielded isolated skeletal elements (three maxillae and a femur) unambiguously referred to Abelisauridae, a Middle Jurassic to Late Cretaceous ceratosaurian clade with a predominantly Gondwanan distribution. Although two clearly distinct abelisaurid taxa have been recognized in sub...

We describe the partially preserved femur of a large-bodied theropod dinosaur from the Cenomanian “Kem Kem Compound Assemblage” (KKCA) of Morocco. The fossil is housed in the Museo Geologico e Paleontologico “Gaetano Giorgio Gemmellaro” in Palermo (Italy). The specimen is compared with the theropod fossil record from the KKCA and coeval assemblages...

In 1841, Richard Owen erected Cetiosaurus (‘whale lizard’) for a series of giant vertebrae he interpreted as the remains of a marine reptile similar to cetaceans. Further discoveries revealed that such material were the first remains ever collected of fully terrestrial animals, now known as sauropod dinosaurs. Among sauropods, the holotype of the...

Here we report for the first time on the presence of ichthyosaurs in Sicily, southern Italy. The deposit of origin (Mufara Formation) can be dated to the upper Carnian (Tuvalian substage) based on a typical association of ammonites, one of which (Shastites sp.) is embedded in the sediment still encrusting one of the bone specimens recently found. T...

The “Bonaventura Gravina” Collection of the Earth Science Museum of Catania (Italy) includes an ichthyosaur specimen of unknown geographic and stratigraphic provenance, age, and taxonomic determination. On comparison with other fossils from the same collection it was established that the specimen is from Böll, southwestern Germany; the ammonites pr...

The fossil record of Mesozoic theropod dinosaurs is relatively fragmentary in the Southern Europe; the latter usually considered a pivotal area from a paleobiogeographic perspective, as a possible "bridge" for faunal interchange across Laurasia and Gondwana during the Mesozoic. Here, we use a well sampled phylogeny of Theropoda as a framework for f...

Descrizione preliminare dell’esemplare di ittiosauro Stenopterygius MSDTC 316 467 appartenente alla collezione ”Bonaventura Gravina” del Museo di Scienze della Terra dell’Università di Catania.