Federico Fanti

New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia

Two new specimens of the oviraptorid theropod Nemegtomaia barsboldi from the Nemegt Basin of southern Mongolia are described. Specimen MPC-D 107/15 was collected from the upper beds of the Baruungoyot Formation (Campanian-Maastrichtian), and is a nest of eggs with the skeleton of the assumed parent of Nemegtomaia on top in brooding position. Much of the skeleton was damaged by colonies of dermestid coleopterans prior to its complete burial. However, diagnostic characters are recovered from the parts preserved, including the skull, partial forelimbs (including the left hand), legs, and distal portions of both feet. Nemegtomaia represents the fourth known genus of oviraptorid for which individuals have been found on nests of eggs. The second new specimen, MPC-D 107/16, was collected a few kilometers to the east in basal deposits of the Nemegt Formation, and includes both hands and femora of a smaller Nemegtomaia individual. The two formations and their diverse fossil assemblages have been considered to represent sequential time periods and different environments, but data presented here indicate partial overlap across the Baruungoyot-Nemegt transition. All other known oviraptorids from Mongolia and China are known exclusively from xeric or semi-arid environments. However, this study documents that Nemegtomaia is found in both arid/aeolian (Baruungoyot Formation) and more humid/fluvial (Nemegt Formation) facies.

A new sauropod dinosaur from the Early Cretaceous of Tunisia with extreme avian-like pneumatization

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 refer it to a new rebbachisaurid sauropod, Tataouinea hannibalis gen. et sp. nov. The Tunisian specimen shows a complex pattern of caudosacral and pelvic pneumatization--including the first report of an ischial pneumatic foramen among Dinosauria--strongly supporting the presence of abdominal air sacs. Character optimization among Rebbachisauridae indicates that in the caudal vertebrae, pneumatization of the neural arches preceded that of the centra; in the pelvis, pneumatization of the bones adjacent to the sacrum preceded that of more distal elements. Tataouinea was more closely related to European nigersaurines than to otherwise Gondwanan rebbachisaurids; this supports an Afro-European route for rebbachisaurid dispersal.

New Information on Tataouinea hannibalis from the Early Cretaceous of Tunisia and Implications for the Tempo and Mode of Rebbachisaurid Sauropod Evolution

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 facies distribution at the main quarry and a revision of the vertebrate fauna associated with the skeleton. Data provide information on a complex ecosystem dominated by crocodilian and other brackish water taxa. Taphonomic interpretations indicate a multi-event, pre-burial history with a combination of rapid segregation in high sediment supply conditions and partial subaerial exposure of the carcass. After the collection in 2011 of the articulated sacrum and proximalmost caudal vertebrae, all showing a complex pattern of pneumatization, newly discovered material of the type specimen allows a detailed osteological description of Tataouinea. The sacrum, the complete and articulated caudal vertebrae 1–17, both ilia and ischia display asymmetrical pneumatization, with the left side of vertebrae and the left ischium showing a more extensive invasion by pneumatic features than their right counterparts. A pneumatic hiatus is present in caudal centra 7 to 13, whereas caudal centra 14–16 are pneumatised by shallow fossae. Bayesian inference analyses integrating morphological, stratigraphic and paleogeographic data support a flagellicaudatan-rebbachisaurid divergence at about 163 Ma and a South American ancestral range for rebbachisaurids. Results presented here suggest an exclusively South American Limaysaurinae and a more widely distributed Rebbachisaurinae lineage, the latter including the South American taxon Katepensaurus and a clade including African and European taxa, with Tataouinea as sister taxon of Rebbachisaurus. This scenario would indicate that South America was not affected by the end-Jurassic extinction of diplodocoids, and was most likely the centre of the rapid radiation of rebbachisaurids to Africa and Europe between 135 and 130 Ma.

FIRST RECORD OF BIRD TRACKS IN THE LATE CRETACEOUS (CENOMANIAN) OF TUNISIA

Abstract The discovery of fossil bird tracks from the Cenomanian Kerker Member (Zebbag Formation) in southern Tunisia represents the oldest report of fossil birds from the Cretaceous of continental Africa. Three small bird tracks were discovered in a track-bearing surface dominated by tridactyl dinosaur footprints and are attributed to the ichnogenus Koreanaornis. This represents the first occurrence of this ichnogenus in Africa and indicates a worldwide distribution of these shorebirdlike tracks, previously known only from Asia and North America. Tracks described in this study are also smaller than any other fossil bird track known to date, thus they can be included in the minute size class following modern bird track groups. A comparison with present-day shorebird tracks indicates strong similarities in size, morphology, and environment with extant members of the Actitis genus, commonly known as sandpipers, which inhabit arid central African tidal flats. The occurrence of bird tracks in the early Late Cretaceous of Tunisia also brings important new insight into the paleoecology of an area previously thought to be a site of exclusively marine deposition.

Vertebrate Tracksites in the Middle Jurassic-Upper Cretaceous of South Tunisia

Four vertebrate tracksites from the Middle Jurassic and Upper Cretaceous in the Tataouine basin of southern Tunisia are described. Approximately 130 tridactyl footprints distributed over an area of 200 square meters, preserved on Callovian beds exposed at the Beni Ghedir site, represent the oldest evidence of a dinosaur fauna in Tunisia. In addition, three tracksites—Chenini, Ksar Ayaat, and Jebel Boulouha—have been discovered in the Cretaceous beds of the upper Continental Intercalaire, previously considered as a strictly marine depositional sequence. In addition to dinosaur tracks, the Chenini tracksite (late Albian) includes poorly preserved crocodilian tracks, and footprints assigned to a pleurodiran turtle have been recovered at the Ksar Ayaat locality (early Cenomanian). The Jebel Boulouha tracksite is dominated by well-preserved tridactyl tracks referred to small-sized theropods. Depositional settings of each tracksite have been defined on stratigraphic and sedimentologic data, and tracks were ascribed to different ichnocoenoses in relation to their paleoenvironments. This new and differentiated track record gives important information on how the fossil vertebrate fauna changed in southern Tunisia during mid-Jurassic to mid-Cretaceous times. These data provide a unique and useful census of tetrapod associations along the southern margin of the peri-Mediterranean area.

Borioteiioidean lizard skulls from Kleskun Hill (Wapiti Formation; upper Campanian), west-central Alberta, Canada

ABSTRACT New material of borioteiioidean lizards (Squamata: Scincomorpha) from west-central Alberta, Canada, represent the first and northernmost record of multiple articulated skull elements from the Cretaceous of North America. Specimens were recovered from the fluvial beds of the Wapiti Formation (Campanian) within a bentonitic paleosol exposed at the Kleskun Hill Park, east of the city of Grande Prairie. Such beds accumulated during the maximum transgression of the Bearpaw Seaway (73–74 Ma), thus providing crucial information on lizard faunas during a time interval represented in most of coeval North American deposits by marine strata. Cranial material ascribed to Socognathus unicuspis give the occasion for a revision of the taxon with respect to osteologically better-known Polyglyphanodon sternbergi from the Late Cretaceous of Utah as well as a comparison with several lizards reported from coeval strata of Mongolia. Furthermore, a new scincomorphan lizard, Kleskunsaurus grandeprairiensis, gen. et sp. nov., is described. Socognathus unicuspis is assigned to Chamopsiidae, taxon nov., which also includes Chamops, Leptochamops, and several other morphologically similar taxa from the Cretaceous of North America.

New Data on Two Large Dinosaur Tracksites from the Upper Jurassic of Eastern Turkmenistan (Central Asia)

In this study, we present new data on the Hojapil-Ata dinosaur mega-tracksite located in the Koitendag National Park of eastern Turkmenistan, central Asia. Accurate GPS mapping, three-dimensional data on preserved tracks, and comparison with previous studies provides now a detailed database for this site. The track-bearing surface, Upper Jurassic in age, is discontinuously exposed over an area of 28.500 square meters, with 24 trackways and at least 913 footprints preserved. The collected data support the previously identified co-occurrence of the two ichnogenera Megalosauripus and Therangospodus and allow us to propose an amended systematic description of M. uzbekistanicus. In addition, a previously unreported site located a few km to the east of the main tracksite is described. The track-bearing surface extends over 24.000 square meters, and 34 trackways and 730 footprints have been mapped. These two sites represent the sole evidence of dinosaurs in Turkmenistan and they are among the largest in the world. Data collected for this study document that both localities are deteriorating at an increasing rate due to natural erosion and human activities. High-resolution laser scanner and digital photogrammetry allowed for the realization of comparable digital 3D models of dinosaur track to guarantee their fruition for future research.

Cretaceous Continental Bridges, Insularity, and Vicariance in the Southern Hemisphere: Which Route Did Dinosaurs Take?

The history of dispersal of biota during the Mesozoic in the southern hemisphere is much debated. Clearly, the sequential break-up of Gondwana produced physical barriers that must, variously, have hampered dispersal events, and therefore impacted the phylogenetic hypotheses. Did various terrestrial organisms undergo dispersal via recently claimed continental bridges? When were the geographic and environmental conditions at an optimum for diffusion during Mesozoic times? Dinosaurs are arguably the most relevant group for illuminating the biogeography of the southern landmasses during the Cretaceous. Their vast stratigraphic and geographic occurrence is intimately linked to the evolution of Gondwana. Recent discoveries from all southern landmasses challenge several vicariant models. This study summarizses the most significant geologic, palaeogeographic, palaeontologic, and phylogenetic data on Cretaceous Gondwanan dinosaur evolution, with particular emphasis on the ephemeral land bridges that bulk large in recently developed biogeographic models. Comparison between different datasets accords with a complex and sequential mix of vicariance and dispersal patterns characterizing the fabric of dinosaurian faunas at that time. This study probes the significance of ephemeral intercontinental connections with regard to the biotic dispersal in the Late Cretaceous. An earlier peak in dinosaur diversity and dispersals seems likely.

An exceptionally preserved Eocene shark and the rise of modern predator–prey interactions in the coral reef food web

BackgroundFollowing extreme climatic warming events, Eocene Lagerstätten document aquatic and terrestrial vertebrate faunas surprisingly similar to modern counterparts. This transition in marine systems is best documented in the earliest teleost-dominated coral reef assemblage of Pesciara di Bolca, northern Italy, from near the end of the Eocene Climatic Optimum. Its rich fauna shows similarities with that of the modern Great Barrier Reef in niche exploitation by and morphological disparity among teleost primary consumers. However, such paleoecological understanding has not transcended trophic levels above primary consumers, particularly in carcharhiniform sharks.ResultsWe report an exceptionally preserved fossil school shark (Galeorhinus cuvieri) from Pesciara di Bolca. In addition to the spectacular preservation of soft tissues, including brain, muscles, and claspers, this male juvenile shark has stomach contents clearly identifiable as a sphyraenid acanthomorph (barracuda). This association provides evidence that a predator–prey relationship between Galeorhinus and Sphyraena in the modern coral reefs has roots in the Eocene. A growth curve of the living species of Galeorhinus fitted to G. cuvieri suggests that all specimens of G. cuvieri from the lagoonal deposits of Bolca represent sexually and somatically immature juveniles.ConclusionThe modern trophic association between higher-degree consumers (Galeorhinus and Sphyraena) has a counterpart in the Eocene Bolca, just as Bolca and the Great Barrier Reef show parallels among teleost primary consumers. Given the age of Bolca, trophic networks among consumers observed in modern coral reefs arose by the exit from the Climatic Optimum. The biased representation of juveniles suggests that the Bolca Lagerstätte served as a nursery habitat for G. cuvieri. Ultraviolet photography may be useful in probing for exceptional soft tissue preservation before common acid preparation methods.

High evolutionary rates and the origin of the Rosso Ammonitico Veronese Formation (Middle-Upper Jurassic of Italy) reptiles

Abstract 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 the nineteenth century and referred to Plesiosaurus: elements are here described and interpreted as a chimerical association of crocodylomorph and plesiosaurian bones, providing the first co-occurrence of these clades in the RAVFm. The second plesiosaurian is the associated skeleton that we refer to Anguanax zignoi gen. et sp. nov. Bayesian phylogenetic analysis confirms the basal geosaurine affinities of Neptunidraco resulted by parsimony analysis. Using both methods, Anguanax was recovered as a basal pliosaurid, sister group of the clade including Marmornectes and Thalassophonea. Bayesian inference methods indicate that both Italian lineages diverged from other known lineages between 176 and 171 Mya, also showing divergence rates significantly higher than any other representative of their respective clades. We suggest a phase of rapid evolutionary adaptation to deeper marine environments in the ancestors of the Rosso Ammonitico Veronese reptiles as a response to the latest Liassic regressive regime in Northern Tethys.