Andrea Cau

The recent discovery of small paravian theropod dinosaurs with well-preserved feathers in the Middle-Late Jurassic Tiaojishan Formation of Liaoning Province (northeastern China) has challenged the pivotal position of Archaeopteryx, regarded from its discovery to be the most basal bird. Removing Archaeopteryx from the base of Avialae to nest within...

Turning large dinosaurs into small birds Most paleontologists agree that birds are descended from dinosaurs. How did such large terrestrial or aquatic animals evolve into small feathered fliers? Lee et al. used two large databases of theropod morphology to explore possible evolutionary patterns that may have driven this dramatic transformation (see...

Maniraptora includes birds and their closest relatives among theropod dinosaurs. During the Cretaceous period, several maniraptoran lineages diverged from the ancestral coelurosaurian bauplan and evolved novel ecomorphologies, including active flight, gigantism, cursoriality and herbivory. Propagation X-ray phase-contrast synchrotron microtomograph...

Birds are one of the most successful groups of vertebrates. The origin of birds from their reptilian ancestors is traditionally rooted near the Jurassic "Urvogel" Archaeopteryx, an approach that has contributed in defining the dichotomy between the "reptilian" (pre-Archaeopteryx) and "avian" (post-Archaeopteryx) phases of what is instead a single e...

Metriorhynchidae is a clade of marine-adapted crocodilians known from several Middle Jurassic–Early Cretaceous specimens collected predominantly in South America and Europe, but poorly known in the northern margin of Gondwana. The “Portomaggiore crocodile” is the most complete specimen of an Italian metriorhynchid to date: it consists of a partial...

The study of the Cretaceous birds closest to the living euornithine species has mainly focused on the evolutionary patterns leading to the modern group. Yet, the morphological and ecological diversity of the euornithine branches not directly ancestral to the crown-group is probably underestimated. A new euornithine bird, Shuilingornis angelai gen....

Known since the 19 th Century, the compsognathids are among the smallest predatory dinosaurs, and include the first feathered non-avian species found. Traditionally, compsognathids have been considered small and unspecialized coelurosaurs, closer to birds than large-bodied forms like allosauroids and megalosaurids. Yet, all known compsognathids are...

A new small-bodied theropod dinosaur, Migmanychion laiyang gen. et sp. nov., is erected based on appendicular skeletal material from the Lower Cretaceous of the Pigeon Hill locality, Inner Mongolia, China. This theropod shows a peculiar combination of features in the hand, in part shared with therizinosauroids, oviraptorosaurs and with the enigmati...

We report a new fossil-bearing locality from the “Chaotic Complex” units in the Northern Apennine Chain of the Emilia-Romagna Region (northern Italy). The material collected includes an articulated series of nine caudal vertebrae referable to a large-bodied ichthyosaur. Based on the nannofossil assemblage sampled from the matrix encasing the verteb...

Dromaeosaurids were bird-like dinosaurs with a predatory ecology known to forage on fish, mammals and other dinosaurs. We describe Daurlong wangi gen. et sp. nov., a dromaeosaurid from the Lower Cretaceous Jehol Biota of Inner Mongolia, China. Exceptional preservation in this specimen includes a large bluish layer in the abdomen which represents on...

The ‘Kem Kem Compound Assemblage’ (KKCA) along the Algerian-Moroccan border is a series of fossiliferous localities, Cenomanian in age, particularly rich in large-bodied theropod dinosaurs. Two species of carcharodontosaurid allosauroids have been identified in these units, Carcharodontosaurus saharicus and Sauroniops pachytholus. Recently, the val...

Eotyrannus lengi Hutt et al., 2001 from the Lower Cretaceous Wessex Formation (part of the Wealden Supergroup) of the Isle of Wight, southern England, is described in detail, compared with other theropods, and evaluated in a new phylogenetic analysis. Eotyrannus is represented by a single individual that would have been c. 4.5 m long; it preserves...

A new enantiornithine, Musivavis amabilis n. gen. n. sp., is reported from the Lower Cretaceous Jehol Biota in western Liaoning, China. The new taxon is similar to the bohaiornithids in the robust subconical teeth, bluntly expanded omal ends of the furcula, caudolaterally oriented lateral trabeculae with triangular distal ends of the sternum, and a...

Borogovia gracilicrus is a small-bodied theropod dinosaur from the Maastrichtian (Upper Cretaceous) Nemegt Formation of southern Mongolia. The taxon is based on a single fragmentary specimen preserving only the distal part of the hindlimbs. The morphology of Borogovia shows a peculiar combination of features, some of which are traditionally conside...

Theropoda is the monophyletic group including all predatory dinosaurs and birds. The study of theropod dinosaurs from Italy is a recent field, not more than three decades old. Although the current record of skeletal remains is limited to two individuals and one isolated bone, the quality and significance of the theropod material so far discovered i...

Spinosaurids are among the most distinctive and yet poorly-known of large-bodied theropod dinosaurs, a situation exacerbated by their mostly fragmentary fossil record and competing views regarding their palaeobiology. Here, we report two new Early Cretaceous spinosaurid specimens from the Wessex Formation (Barremian) of the Isle of Wight. Large-sca...

The furcula is a distinctive element of the pectoral skeleton in birds, which strengthens the shoulder region to withstand the rigor of flight. Although its origin among theropod dinosaurs is now well-supported, the homology of the furcula relative to the elements of the tetrapod pectoral girdle (i.e., interclavicle vs clavicles) remains controvers...

A new jeholornithiform - Kompsornis longicaudus gen. et sp. nov. - is reported based on a nearly complete specimen from the Jehol Biota in western Liaoning, China. Comprehensive comparisons and phylogenetic analysis, including all published species of Jeholornithiformes, are provided and indicate that Shenzhouraptor sinensis, Jeholornis prima, Jixi...

Observations of temporal overlap of niche occupation among Late Cretaceous marine amniotes suggest that the rise and diversification of mosasauroid squamates might have been influenced by competition with or disappearance of some plesiosaur taxa. We discuss that hypothesis through comparisons of the rates of morphological evolution of mosasauroids...

Two decades of paleontological discoveries of basal birds and non-avian theropods with preserved integumentary structures, especially in Late Jurassic to Early Cretaceous deposits from northeastern China, have greatly improved our understanding of the origin and early evolution of birds and their plumage. Here, we present a concise review of the pl...

We describe a new taxon of advanced ornithuromorph bird, Khinganornis hulunbuirensis gen. et sp. nov., from the previously unreported Pigeon Hill locality of the Lower Cretaceous Longjiang Formation in the northern Greater Khingan Range area of Inner Mongolia, China. A cladistics analysis resolves K. hulunbuirensis as the sister group of a clade fo...

The dromaeosaurid theropod Halszkaraptor escuilliei is characterized by several unusual features absent in other paravians, part of which has been interpreted as diagnostic of a novel lineage adapted to a semiaquatic ecology. Recently, these evolutionary and ecological interpretations have been challenged, and Halszkaraptor has been claimed to be a...

A new ceratosaurian theropod dinosaur, Huinculsaurus montesi gen. et sp. nov., is described here. This taxon is based on the last three dorsal vertebrae and the first and second sacral vertebrae found in association at Aguada Grande, Neuquén Province, Argentina. Although fragmentary, Huinculsaurus shows a unique mix of features which differentiates...

Neptunidraco ammoniticus is a thalattosuchian crocodylomorph from the Rosso Ammonitico Veronese Formation (RAVF, Middle Jurassic) of northern Italy. Erected from one partial specimen, Neptunidraco is pivotal in reconstructing thalattosuchian evolution, being it the oldest known member of Metriorhynchidae. Two additional RAVF thalattosuchians have b...

For the Upper Triassic, conodonts are the primary tools utilized in biostratigraphic investigations. For an effective biostratigraphic zonation, the species should be constrained by clear phylogenetic relationships, in which the stratigraphic ranges and taxonomy are reliable. Unfortunately, a phylogenetic framework for the Late Triassic pectiniform...

The homology of the tridactyl hand of birds is a still debated subject, with both paleontological and developmental evidence used in support of alternative identity patterns in the avian fingers. With its simplified phalangeal morphology, the Late Jurassic ceratosaurian Limusaurus has been argued to support a II-III-IV digital identity in birds and...

Hulsanpes perlei is an enigmatic theropod dinosaur from the Baruungoyot Formation (?mid-to upper Campanian, Upper Cretaceous) of Mongolia. It was discovered in 1970, during the third Polish-Mongolian paleontological expedition to the Nemegt Basin. The taxon is known based on a partial braincase and an incomplete right hindlimb. However, the brainca...

Phylogenetic data matrix Data matrix in .tnt format, with scores updated for Hulsanpes. Character list in Cau et al. (2017, supplementary data).

Character statements of Cau (2018) phylogenetic analysis.

Mosasauroid squamates represented the apex predators within the Late Cretaceous marine and occasionally also freshwater ecosystems. Proper understanding of the origin of their ecological adaptations or paleobiogeographic dispersals requires adequate knowledge of their phylogeny. The studies assessing the position of mosasauroids on the squamate evo...

BEAST file for Bayesian analysis

TNT file for parsimony analyses

Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have...

Brachauchenine pliosaurids were marine macropredatory reptiles that might have been the only evolutionary lineage of pliosaurid plesiosaurians that crossed the Jurassic-Cretaceous boundary. Yet progress in understanding their origins and phylogenetic relationships has been hindered by limited knowledge of Early Cretaceous brachauchenine pliosaurid...

The caudofemoralis longus muscle (CFL) is the primary limb retractor among non-avian sauropsids, and underwent a dramatic reduction along the dinosaur lineage leading to birds. The osteological correlates of the CFL among fossil reptiles have been controversial, because, contrary to traditional interpretations, the extent of the muscle is not neces...

Bayesian phylogenetic methods integrating simultaneously morphological and strati-graphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa...

Character statements used in phylogenetic analysis

Data file for analysis in BEAST vers.2

Here we describe the first sauropod skeletal remains from the Italian peninsula that also represent the earliest record of titanosaurs in Southern Europe. Scattered bones, including an almost complete anterior caudal vertebra, were found in Cretaceous (AptianeAlbian) marine deposits, some 50 km East of Rome. The vertebra shows a bizarre and perhaps...

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...

The fossil record of ornithischian dinosaurs from Africa is particularly scarce and limited to a few historic localities. In this study we describe new ornithischian remains from the Albian deposits of southern Tunisia (Tataouine Governorate), represented by isolated teeth of large-bodied iguanodontians. Teeth display a wide, diamond-shaped crown w...

Megaraptoridae comprises a clade of enigmatic Gondwanan theropods with characteristic hypertrophied claws on the first and second manual digits. The majority of megaraptorids are known from South America, although a single genus (Australovenator) plus additional indeterminate material is also known from Australia. This clade has a controversial pla...

Four feathered theropods have already been described from the Middle-Late Jurassic Tiaojishan Formation in Liaoning Province (China): Anchiornis huxleyi, Xiaotingia zhengi, Eosinopteryx brevipenna, and Aurornis xui.

Two small bones from the Upper Triassic of Cromhall Quarry (Gloucestershire, England), which are referred in the literature to pterosaurian wing metacarpals, are compared with wing metacarpals of unequivocal pterosaur specimens from the Upper Triassic of Italy and Greenland as well as those of the Liassic Dimorphodon macronyx from England. The two...

The fossil record of metriorhynchids and plesiosaurians from the Rosso Ammonitico Veronese Formation (RAVFm, Middle–Upper Jurassic, Italy) is represented by elements collected between the eighteenth and twentieth centuries. All the metriorhynchid material is referred to the genus Neptunidraco. The first RAVFm plesiosaurian material was collected in...

Mosasauroidea is a species-rich clade of mostly marine, small to gigantic squamates with an evolutionary history recorded exclusively in Upper Cretaceous strata. Although the most distinguishable mosasauroid lineages, such as tylosaurines, plioplatecarpines and derived mosasaurines, have already been adequately recognised decades ago, their interre...

The exceptionally well-preserved Romanian dinosaur Balaur bondoc is the most complete theropod known to date from the Upper Cretaceous of Europe. Previous studies of this remarkable taxon have included its phylogenetic interpretation as an aberrant dromaeosaurid with velociraptorine affinities. However, Balaur displays a combination of both apparen...

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...

The rebbachisaurid sauropod Tataouinea hannibalis represents the first articulated dinosaur skeleton from Tunisia and one of the best preserved in northern Africa. The type specimen was collected from the lower Albian, fluvio-estuarine deposits of the Ain el Guettar Formation (southern Tunisia). We present detailed analyses on the sedimentology and...

Current knowledge of theropod dinosaurs of northern Africa and their diversity during the Early Cretaceous is deceptively fragmentary and commonly associated with inadequate stratigraphic and palaeoecological data. Thereby, confused taxonomic affinities of theropod remains, represented primarily by isolated teeth and fragmentary skeletal remains, r...

In 1787, a fragmentary fossil skull of a crocodylian was discovered in the Altopiano dei Sette Comuni (Veneto, Northern Italy). In 1883, the specimen was referred to a new species of the teleosauroid Steneosaurus, S. barettoni. In this study, the specimen is redescribed and its taxonomic status reviewed. S. barettoni fails to conform to Article 12...

A snout of a large-sized mosasaur from the Upper Cretaceous pelagic-turbiditic deposits of the Argille Scagliose Complex of Northern Italy is described. Nannofossil assemblages from the immediately overlying strata belong to the late but not latest Campanian calcareous nannofossil standard zone CC22, based on the presence of Uniplanarius trifidus a...

Birds are among the most diverse and intensivelystudied vertebrate groups, but many aspects of theirhigher-level phylogeny and evolution still remaincontroversial. One contentious issue concerns theantiquity of modern birds (=crown Aves): the ageof the most recent common ancestor of all livingbirds (Gauthier 1986). Very few Mesozoic fossilsare attr...

The paleontological collection of the Comiso Natural History Museum (Sicily, Italy) includes two ichthyosaurian specimens from the Lower Jurassic Posidonia Shale (southwestern Germany). Based on comparative morphology, we refer them to Temnodontosaurus and Stenopterygius both common genera in the Toarcian of Southern Germany.

Isolated sauropod remains including vertebrae and a humerus from the Aïn El Guettar Formation (Albian, Early Cretaceous) of Tunisia are described. Vertebrae include a slightly procoelous anterior caudal vertebra, amphicoelous middle caudal vertebrae, and strongly procoelous distal caudal vertebrae. The humerus has an anteroposteriorly compressed sh...

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...

Recent interpretations of the postcranial anatomy of sauropod dinosaurs differ about pneumatic features supporting an avian-like ventilatory system; the most conservative workers reject most postcranial pneumatizations as being unambiguous evidence of abdominal air sacs. Here we describe the first articulated dinosaur skeleton from Tunisia and refe...

Plesiosauria is a clade of medium to large bodied marine reptiles with a cosmopolitan distribution ranging from the latest Triassic to the end of the Cretaceous. In Europe, the fossil record of Plesiosauria is mainly known from the Northern latitudes, whereas it is much rarer from the Southern and Mediterranean areas. Here, we report the first arti...

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...

The high intraspecific variability of conodont platform elements in the upper Carnian–lower Norian interval and the proliferation of numerous species in this relatively short time have generated many problems for the understanding of Late Triassic conodont phylogeny, systematics and taxonomy. Since Late Triassic natural assemblages are still unknow...

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...