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Colour reconstructions have provided new insights into the lives of dinosaurs and other extinct animals, by predicting colouration patterns from fossilised pigment-bearing organelles called melanosomes. Although these methods have become increasingly popular, only a small number of dinosaurs have been studied using these techniques, which require exceptional preservation of fossil feathers, leaving open key questions such as whether dinosaurs changed their plumage patterns during ontogeny. Here we reconstruct the feather colouration of an approximately one-year-old individual of the Early Cretaceous dromaeosaurid theropod Wulong bohaiensis, which to our knowledge is the first unequivocal juvenile paravian for which aspects of the original colour has been predicted. Using quadratic discriminant analysis (QDA) and multinomial logistic regression (MLR) on the most comprehensive available datasets, we find strong evidence for iridescent plumage of the forelimb and hindlimb remiges and grey plumage on other portions of the body. This suggests that some juvenile paravians used shiny iridescent feathers for signalling purposes, possibly even before reaching somatic or sexual maturity, and thus we can conclude that this paravian used iridescent signalling for intraspecific communication other than sexual signalling. Finally, our results show that when analysing fossil datasets that are entirely comprised of solid and cylindrical melanosomes QDA consistently outperforms MLR, providing more accurate and higher classification probability colour predictions.

Numerous dromaeosaurid taxa recovered from the Upper Cretaceous strata of the Gobi Desert raise questions over niche partitioning among closely related species. Here, I describe a dromaeosaurid specimen from the Baruungoyot strata of the Khulsan locality, containing a partial skull in close association with the left hind limb. The material can be referred to the velociraptorine Shri devi, until now known only from a single specimen lacking a skull, collected from the same site. The referral is based on the apomorphic morphology of the pes, including the highly hypertrophic ungual of the second digit and details of the metatarsus. The skull of S. devi confirms its close affinities with Velociraptor mongoliensis, but shows distinctive features among Velociraptorinae, including a short antorbital fenestra, a Z-shaped maxillo-jugular suture, a distinct labial ridge above the supralabial foramina row of the maxilla, and the posterior position of the last maxillary tooth. The skull of S. devi is slender, but relatively short when compared to other velociraptorines, suggesting convergence to the North American eudromaeosaurians. The Baruungoyot strata with S. devi represent less arid conditions than the aeolian Djadokhta strata yielding V. mongoliensis, supporting earlier observations linking the elongation of the dromaeosaurid snout with the environment.

Two isolated metatarsals (III and IV) of theropod dinosaurs from the Bostobe Formation (Upper Cretaceous, Santonian–Campanian) of the Shakh-Shakh locality in Kazakhstan are assigned to the representatives of the families Caenagnathidae and Dromaeosauridae, respectively. The metatarsal III of Caena-gnathidae indet. confirms the presence of oviraptorosaurs in the dinosaur assemblage from the Bostobe Formation. This bone is very similar morphologically with the metatarsal III of Elmisaurus rarus Osmólska, 1981 from the Maastrichtian of Mongolia. The metatarsal IV of Dromaeosauridae indet. is characterized by a lateral crest, which among dromaeosaurids is known only for Velociraptor mongoliensis Osborn, 1924 from the Campanian of Mongolia. [ABSTRACT FROM AUTHOR]

Numerous dromaeosaurid taxa recovered from the Upper Cretaceous strata of the Gobi Desert raise questions over niche partitioning among closely related species. Here, I describe a dromaeosaurid specimen from the Baruungoyot strata of the Khulsan locality, containing a partial skull in close association with the left hind limb. The material can be referred to the velociraptorine Shri devi, until now known only from a single specimen lacking a skull, collected from the same site. The referral is based on the apomorphic morphology of the pes, including the highly hypertrophic ungual of the second digit and details of the metatarsus. The skull of S. devi confirms its close affinities with Velociraptor mongoliensis, but shows distinctive features among Velociraptorinae, including a short antorbital fenestra, a Z-shaped maxillo-jugular suture, a distinct labial ridge above the supralabial foramina row of the maxilla, and the posterior position of the last maxillary tooth. The skull of S. devi is slender, but relatively short when compared to other velociraptorines, suggesting convergence to the North American eudromaeosaurians. The Baruungoyot strata with S. devi represent less arid conditions than the aeolian Djadokhta strata yielding V. mongoliensis, supporting earlier observations linking the elongation of the dromaeosaurid snout with the environment. [ABSTRACT FROM AUTHOR]

Colour reconstructions have provided new insights into the lives of dinosaurs and other extinct animals, by predicting colouration patterns from fossilised pigment-bearing organelles called melanosomes. Although these methods have become increasingly popular, only a small number of dinosaurs have been studied using these techniques, which require exceptional preservation of fossil feathers, leaving open key questions such as whether dinosaurs changed their plumage patterns during ontogeny. Here we reconstruct the feather colouration of an approximately one-year-old individual of the Early Cretaceous dromaeosaurid theropod Wulong bohaiensis, which to our knowledge is the first unequivocal juvenile paravian for which aspects of the original colour has been predicted. Using quadratic discriminant analysis (QDA) and multinomial logistic regression (MLR) on the most comprehensive available datasets, we find strong evidence for iridescent plumage of the forelimb and hindlimb remiges and grey plumage on other portions of the body. This suggests that some juvenile paravians used shiny iridescent feathers for signalling purposes, possibly even before reaching somatic or sexual maturity, and thus we can conclude that this paravian used iridescent signalling for intraspecific communication other than sexual signalling. Finally, our results show that when analysing fossil datasets that are entirely comprised of solid and cylindrical melanosomes QDA consistently outperforms MLR, providing more accurate and higher classification probability colour predictions. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan has yielded many isolated bones and teeth representing a variety of non-avian theropod dinosaurs. A pedal phalanx II-2 indicates the presence of a dromaeosaurid theropod that attained a larger body size than any previously known member of that clade. The same formation also yielded a large maxillary fragment that has recently been described as a neovenatorid carcharodontosaurian (Ulughbegsaurus uzbekistanensis). However, this specimen lacks unambiguously diagnostic features of that clade, and its purported carcharodontosaurian characters are either taphonomic artefacts or also shared by dromaeosaurids. Thus, the phylogenetic relationships of Uleghbegsaurus uzbekistanensis remain uncertain. A giant dromaeosaurid occurred together with the medium-sized tyrannosauroid Timurlengia euotica in the Bissekty assemblage. [ABSTRACT FROM AUTHOR]

Dromaeosaurids are poorly known in Europe and their fossil records are mostly postcranial remains. To date, the French faunal records of the family Dromaeosauridae include two taxa: Pyroraptor olympius and Variraptor mechinorum. Nevertheless, their taxonomic validity and phylogenetic relationships as dromaeosaurids are controversial. Here, we report a new record of a dromaeosaurid-like pedal ungual from the 'Grès à Reptiles' Formation (Campanian-Maastrichtian) of the Upper Cretaceous of southern France. The French specimen was assigned to cf. Dromaeosauridae on the basis of an extensive qualitative analysis. The new specimen has a strongly curved morphology with a tall, narrow cross-section, which is one of the most characteristic anatomical features of the family. Direct comparison reveals that the claw is similar to that of Pyroraptor olympius (MNHN BO001) from a stratigraphically correlated locality. [ABSTRACT FROM AUTHOR]

While the terrestrial fossil record of the mid-Cretaceous interval (Aptian to Cenomanian) in North America has been poorly studied, the recent focus on fossil localities from the western United States has offered a more detailed picture of vertebrate diversity, ecosystem dynamics and faunal turnover that took place on the western landmass of Laramidia. This is in stark contrast to the terrestrial record from the eastern landmass of Appalachia, where vertebrate fossils are rare and consist mostly of isolated and fragmentary remains. However, a detailed understanding of these fossil communities during this interval is necessary for comparison of the faunal patterns that developed during the opening of the Western Interior Seaway (WIS). The Woodbine Group of Texas is a Cenomanian age (95-100 mya) deposit consisting of shallow marine, deltaic, and terrestrial communities, which were only recently separated from their western counterparts. These deposits have yielded a wealth of vertebrate remains, yet non-avian theropods are still largely unknown. Recently, multiple localities in the Lewisville Formation of the Woodbine Group have yielded new non-avian theropod material, including numerous isolated teeth and postcranial remains. While largely fragmentary, this material is sufficiently diagnostic to identify the following taxa: a large-bodied carcharodontosaur, a mid-sized tyrannosauroid, a large ornithomimosaur, a large dromaeosaurine, a small dromaeosaurid, a small troodontid, and a small coelurosaur. Some of these groups represent the first occurrence for Appalachia and provide a broader understanding of a newly expanded faunal diversity for the Eastern landmass. The Lewisville Formation theropod fauna is similar in taxonomic composition to contemporaneous deposits in Laramidia, confirming that these groups were widespread across the continent prior to extension of the WIS. The Lewisville Formation documents the transitional nature of Cenomanian coastal ecosystems in Texas while providing additional details on the evolution of Appalachian communities shortly after WIS extension. [ABSTRACT FROM AUTHOR]

Neuroanatomical reconstructions of extinct animals have long been recognized as powerful proxies for palaeoecology, yet our understanding of the endocranial anatomy of dromaeosaur theropod dinosaurs is still incomplete. Here, we used X‐ray computed microtomography (µCT) to reconstruct and describe the endocranial anatomy, including the endosseous labyrinth of the inner ear, of the small‐bodied dromaeosaur, Velociraptor mongoliensis. The anatomy of the cranial endocast and ear were compared with non‐avian theropods, modern birds, and other extant archosaurs to establish trends in agility, balance, and hearing thresholds in order to reconstruct the trophic ecology of the taxon. Our results indicate that V. mongoliensis could detect a wide and high range of sound frequencies (2,368–3,965 Hz), was agile, and could likely track prey items with ease. When viewed in conjunction with fossils that suggest scavenging‐like behaviours in V. mongoliensis, a complex trophic ecology that mirrors modern predators becomes apparent. These data suggest that V. mongoliensis was an active predator that would likely scavenge depending on the age and health of the individual or during prolonged climatic events such as droughts. [ABSTRACT FROM AUTHOR]

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 transitional form between non-dromaeosaurid maniraptoriforms and other dromaeosaurids: following that reevaluation, its peculiar body plan would represent the retention of several maniraptoran plesiomorphies, lost among other dromaeosaurids, and not an adaptation to a novel ecology. This alternative scenario is here carefully investigated and tested. It is shown that most statements supporting this scenario are based on misinterpretation of anatomical traits and bibliography. Once these statements have been corrected, character state transition optimization over a well-supported phylogenetic framework indicates that the large majority of the peculiar features of the Halszkaraptor lineage are derived novelties acquired by the latter after its divergence from the last ancestor shared with eudromaeosaurs, and thus are not maniraptoriform plesiomorphies. At least seven novelties of the Halszkaraptor lineage are convergently acquired with spinosaurids, and are integrated in semiaquatic adaptations: one of these is reported here for the first time. The amount of morphological divergence of Halszkaraptorinae from the ancestral dromaeosaurid condition is comparable to those of Microraptorinae and Velociraptorinae. Among extant taxa, the sawbills (Mergini, Anseriformes) show the closest ecomorphological similarity with the peculiar body plan inferred for Halszkaraptor. The halszkaraptorine bauplan is thus confirmed as a derived amphibious specialization, and does not represent a "transitional" stage along the evolution of dromaeosaurids. [ABSTRACT FROM AUTHOR]

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 braincase fragment has never been described nor illustrated. We redescribe all elements that form the holotype of Hulsanpes and discuss the affinities of this taxon. The braincase fragment is interpreted as belonging to the inner ear region, and includes the floccular recess and part of the labyrinth. Hulsanpes perlei is confirmed as a valid taxon, diagnosed by a unique combination of metatarsal characters, including two autapomorphies. Historically, it represents the oldest record of the recentlyes tablished clade Halszkaraptorinae. Our findings identify subcursorial adaptations for Hulsanpes, shared with Mahakala, and differentiating them from Halszkaraptor. As such, appendicular disparity in the potentially sympatric halszkaraptorines suggest a reduced ecological overlap among these taxa, which may explain the co-occurrence of multiple species of this clade during the latest Cretaceous in what is now the Nemegt Basin. [ABSTRACT FROM AUTHOR]

Abstract During the Cretaceous period, North America was divided into two landmasses, the eastern Appalachia and western Laramidia. Recent research on several sites scattered across the eastern margin of North America has allowed for the analysis of vertebrate faunas from the once obscure terrestrial fossil record of Appalachia, revealing the landmass harbored a distinctive fauna composed of mostly relict forms. One geological unit that has produced a comparatively extensive record of terrestrial vertebrates, including non-avian dinosaurs, is the middle Campanian Tar Heel Formation of North Carolina. Here, the first definitive occurrence of a dromaeosaurid from the Tar Heel Formation is reported on the basis of a tooth from a fairly large member of that group. This tooth clusters with those of dromaeosaurine dromaeosaurids from the western United States and Canada in morphometric analysis, differing in morphology and size from other dromaeosaurid teeth from southeastern North America that have been assigned to saurornitholestines or considered indeterminate. The tooth described herein is intermediate in size between those of smaller dromaeosaurids like Saurornitholestes and gigantic forms like Dakotaraptor , filling the gap between larger- and smaller-bodied dromaeosaurids from the Late Cretaceous. [ABSTRACT FROM AUTHOR]

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 braincase fragment has never been described nor illustrated. We redescribe all elements that form the holotype of Hulsanpes and discuss the affinities of this taxon. The braincase fragment is interpreted as belonging to the inner ear region, and includes the floccular recess and part of the labyrinth. Hulsanpes perlei is confirmed as a valid taxon, diagnosed by a unique combination of metatarsal characters, including two autapomorphies. Historically, it represents the oldest record of the recently-established clade Halszkaraptorinae. Our findings identify subcursorial adaptations for Hulsanpes, shared with Mahakala, and differentiating them from Halszkaraptor. As such, appendicular disparity in the potentially sympatric halszkaraptorines suggest a reduced ecological overlap among these taxa, which may explain the co-occurrence of multiple species of this clade during the latest Cretaceous in what is now the Nemegt Basin.

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 braincase fragment has never been described nor illustrated. We redescribe all elements that form the holotype of Hulsanpes and discuss the affinities of this taxon. The braincase fragment is interpreted as belonging to the inner ear region, and includes the floccular recess and part of the labyrinth. Hulsanpes perlei is confirmed as a valid taxon, diagnosed by a unique combination of metatarsal characters, including two autapomorphies. Historically, it represents the oldest record of the recentlyestablished clade Halszkaraptorinae. Our findings identify subcursorial adaptations for Hulsanpes, shared with Mahakala, and differentiating them from Halszkaraptor. As such, appendicular disparity in the potentially sympatric halszkaraptorines suggest a reduced ecological overlap among these taxa, which may explain the co-occurrence of multiple species of this clade during the latest Cretaceous in what is now the Nemegt Basin. [ABSTRACT FROM AUTHOR]

Isolated sacrum fragments, manual ungual phalanges, and a third metatarsal from the Upper Cretaceous (Santonian) Yalovach Formation at the Kansai locality in Tajikistan, show similarities to those elements in various dromaeosaurid theropods and are referred to Kansaignathus sogdianus , previously described on the basis of a dentary from the same locality. The phylogenetic analysis incorporating the new characters from these elements confirms phylogenetic position of Kansaignathus as the basalmost Asiatic velociraptorine. It is also the oldest known member of this clade in Asia and worldwide. [ABSTRACT FROM AUTHOR]

Dakotaraptor steini is a recently described dromaeosaurid dinosaur from the Upper Cretaceous (Maastrichtian) Hell Creek Formation of South Dakota. Included within the D. steini hypodigm are three elements originally identified as furculae, one of which was made part of the holotype specimen. We show that the elements described as D. steini ‘furculae’ are not theropod dinosaur furculae, but are rather trionychid turtle entoplastra referable to cf. Axestemys splendida. The hypodigm of D. steini should be adjusted accordingly.

Theropods form a taxonomically and morphologically diverse group of dinosaurs that include extant birds. Inferred relationships between theropod clades are complex and have changed dramatically over the past thirty years with the emergence of cladistic techniques. Here, we present a brief historical perspective of theropod discoveries and classification, as well as an overview on the current systematics of non-avian theropods. The first scientifically recorded theropod remains dating back to the 17th and 18th centuries come from the Middle Jurassic of Oxfordshire and most likely belong to the megalosaurid Megalosaurus. The latter was the first theropod genus to be named in 1824, and subsequent theropod material found before 1850 can all be referred to megalosauroids. In the fifty years from 1856 to 1906, theropod remains were reported from all continents but Antarctica. The clade Theropoda was erected by Othniel Charles Marsh in 1881, and in its current usage corresponds to an intricate ladder-like organization of 'family' to 'superfamily' level clades. The earliest definitive theropods come from the Carnian of Argentina, and coelophysoids form the first significant theropod radiation from the Late Triassic to their extinction in the Early Jurassic. Most subsequent theropod clades such as ceratosaurs, allosauroids, tyrannosauroids, ornithomimosaurs, therizinosaurs, oviraptorosaurs, dromaeosaurids, and troodontids persisted until the end of the Cretaceous, though the megalosauroid clade did not extend into the Maastrichtian. Current debates are focused on the monophyly of deinonychosaurs, the position of dilophosaurids within coelophysoids, and megaraptorans among neovenatorids. Some recent analyses have suggested a placement of dilophosaurids outside Coelophysoidea, Megaraptora within Tyrannosauroidea, and a paraphyletic Deinonychosauria with troodontids placed more closely to avialans than dromaeosaurids. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous of England has produced a diverse assemblage of dinosaurs, including ornithischians, sauropods, and theropods. The origins of this assemblage are poorly understood. Here, we describe a new dromaeosaurid, Vectiraptor greeni gen. et sp. nov., from the Barremian Wessex Formation of the Isle of Wight. The animal is represented by associated dorsal vertebrae and a partial sacrum. Dorsal vertebrae are short, with pleurocoels, camellate pneumatization, stalked parapophyses and enlarged neural canals. Neural spines are tall, with large ligament scars. Sacral centra lack pleurocoels but have large neural canals and foramina suggesting pneumatization. These characters suggest affinities with Dromaeosauridae and specifically the derived, large-bodied Eudromaeosauria. Vectiraptor resembles Early Cretaceous eudromaeosaurs from North America, suggesting a faunal exchange between Europe and North America. The diverse Early Cretaceous dinosaur assemblage found in England and Europe resulted from dispersal from North America, Asia, and West Gondwana, likely involving both land bridges and oceanic dispersal. Europe served as a biotic crossroads in the Early Cretaceous, allowing faunal interchange between landmasses. [ABSTRACT FROM AUTHOR]

Skeletal remains of dromaeosaurid theropods are uncommon in the richly fossiliferous continental strata of the Upper Cretaceous (Turonian) Bissekty Formation of the Kyzylkum Desert in Uzbekistan. The phylogenetic position of the first published specimen, a partial braincase designated as the holotype of Itemirus medullaris Kurzanov, 1976, has long been contentious. Our examination of the specimen supports its attribution to Dromaeosauridae. Additional, mostly well-preserved dromaeosaurid skeletal remains from the Bissekty Formation include cranial bones, teeth, vertebrae, and some podial elements. They are tentatively referred to the same taxon, Itemirus medullaris, and establish the presence of dromaeosaurid paravians in present-day Central Asia during the Turonian. [ABSTRACT FROM AUTHOR]

Dromaeosaurids from the Maastrichtian of North America have a poor fossil record and are known largely from isolated teeth, which have typically been referred to taxa based on more complete material from earlier Campanian strata. An almost complete maxilla with well-preserved dentition and an associated dentary from the Hell Creek Formation of Montana are used to establish a new dromaeosaurid taxon in the latest Maastrichtian, immediately prior to the end-Cretaceous extinction event. Acheroraptor temertyorum gen. et sp. nov. is differentiated from other dromaeosaurids on the basis of a hypertrophied postantral wall that projects posteriorly into the antorbital fenestra, a maxillary fenestra positioned low in the antorbital fossa and directly posterior to the promaxillary fenestra, and distinctive dentition with marked apicobasal ridges. The new material allows a dromaeosaurid from the Maastrichtian of North America to be placed within a phylogenetic framework for the first time. Phylogenetic analysis suggests Acheroraptor is a velociraptorine that is more closely related to Asian dromaeosaurids, including Tsaagan and Velociraptor, than it is to Dromaeosaurus, Saurornitholestes, or any other taxon from North America. As part of the Lancian Tyrannosaurus– Triceratops fauna, A. temertyorum is the latest occurring dromaeosaurid. Its relationships and occurrence suggest a complex historical biogeographic scenario that involved multiple, bi-directional faunal interchanges between Asia and North America during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Abstract: New dinosaur track assemblages were discovered recently in the Tianjialou Formation of the Lower Cretaceous Dasheng Group in Shandong Province, China. Theropods are represented by the trackways of two different medium-sized groups: (1) tridactyl tracks with a typical mesaxonic shape; (2) functionally didactyl tracks attributed to deinonychosaurian theropods. The latter report, the third from the Cretaceous of Shandong Province, enlarges the global record of didactyl theropod tracks, until now sparsely documented from only a few locations in Asia, North America and Europe. A number of features in the dromaeosaur trackway suggest the assignment to cf. Dromaeosauripus. Several medium-sized trackways resemble the narrow-gauge, small manus ichnogenus Parabrontopodus, and one large trackway is characterised by a wide-gauge and large manus, similar to Brontopodus. This suggests the co-occurrence of two different sauropod groups. A further component in these ichnoassemblages is a tetradactyl morphotype and trackways of ornithischian affinity that are tentatively attributed to psittacosaurs. [Copyright &y& Elsevier]

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Islands are noted for the occurrence of aberrant, endemic, and dwarfed taxa (the "island effect"). Late Cretaceous vertebrate assemblages of Romania and elsewhere in Europe are classic examples of island faunas in the fossil record, and are characterized by dwarfed herbivorous dinosaurs and other endemic taxa that are noticeably primitive relative to their mainland contemporaries. Fossils of the predators inhabiting the European paleoislands, however, are exceptionally rare and fragmentary. We describe a new dromaeosaurid theropod, based on an articulated skeleton from the Maastrichtian of Romania, which represents the most complete predatory dinosaur from the middle to Late Cretaceous of Europe. This taxon is characterized by a peculiar body plan, most notably extensive fusion in the hand and distal hindlimb, a highly retroverted pelvis with enlarged femoral muscle attachments, and a pair of hyperextensive pedal claws. However, unlike the island-dwelling herbivorous dinosaurs, its closest relatives are contemporary similar-sized Laurasian taxa, indicating faunal connections between Asia and the European islands late into the Cretaceous. This theropod provides support for the aberrant nature of the Late Cretaceous European island-dwelling dinosaurs, but indicates that predators on these islands were not necessarily small, geographically endemic, or primitive. [ABSTRACT FROM AUTHOR]

Abstract: Some isolated teeth of theropod and sauropod dinosaurs from the Cenomanian (Late Cretaceous) of Charentes are described. Two new teeth of Troodontidae confirm the presence of this theropod family, previously based on a single specimen. New dental morphotypes are recognized within Dromaeosauridae and Brachiosauridae in comparison with those already known from Charentes. Lastly, a very small tooth is tentatively assigned to an embryonic or neonatal sauropod. The palaeobiogeographical history of European hadrosauroids is briefly discussed. This history was probably more complex than it appears, involving exchanges with both North America and Asia as early as the mid-Cretaceous (Albian–Cenomanian). [Copyright &y& Elsevier]

Abstract: Dinosaur remains from Upper Cretaceous outcrops of northern Gondwana are extremely rare, in contrast with the much richer sample of coeval beds from southern Gondwana. Dinosaur remains from the uppermost Cretaceous Ortega locality of the Upper Magdalena Basin (Maastrichtian) of the Department of Tolima, Colombia, provides new information on northern Gondwanan faunas of this time. A revision of dinosaur material from this outcrop, consisting of three theropod shed teeth, reveals the presence of two morphotypes. One of them is referred to Abelisauridae based on the presence of crowns with mesial margin with a strong curvature beginning at about the second-third of the crown height and straight to slightly concave distal margin. The second morphotype exhibits un-serrated mesial and distal margins without carinae and no constriction at the base of the crown, a combination of features only observed in unenlagiine dromaeosaurids within Theropoda. Members of these clades are also present in coeval beds of southern and central South America, Madagascar, northern Africa, and India, indicating a cosmopolitan distribution in western and central Gondwana during the Late Cretaceous. Regarding South America, abelisaurid and probably dromaeosaurid theropods are recorded across a large latitudinal area, from the Palaeo-Equator to considerably high palaeo-latitudes in Patagonia, and probably spanning quite different environmental conditions. [Copyright &y& Elsevier]

Abstract: Theropod teeth from the Bajo Barreal Formation (Upper Cretaceous: Cenomanian–Turonian) at the “estancia Ocho Hermanos”, Chubut Province are described. Most of them show features of Abelisauroidea, a clade already represented in the Bajo Barreal Formation by Xenotarsosaurus bonapartei and other isolated remains including a left maxilla. Dromaeosauridae and Carcharodontosauridae represent the first record of these taxa for the Bajo Barreal Formation. Besides this, at least three theropod clades (Abelisauroidea, Carcharodontosauridae, and Dromaeosauridae) coexisted in central Patagonia during the Cenomanian–Turonian along with other theropods as Aniksosaurus darwini and Megaraptor sp. [Copyright &y& Elsevier]

Abstract: The dinosaur fauna of the palynologically dated lower Berriasian Skyttegård Member of the Rabekke Formation on the Baltic island of Bornholm, Denmark, is represented by isolated tooth crowns. The assemblage is restricted to small maniraptoran theropods, assigned to the Dromaeosauridae incertae sedis and Maniraptora incertae sedis. The dromaeosaurid teeth are characterized by their labiolingually compressed and distally curved crowns that are each equipped with a lingually flexed mesial carina and a distinctly denticulated distal cutting edge. A morphologically aberrant tooth crown (referred to as Maniraptora incertae sedis) has triangular denticles of uneven width, a feature occasionally found in Upper Cretaceous hesperornithiform toothed diving birds, but also in premaxillary teeth of the velociraptorine Nuthetes from the Lower Cretaceous of England. [Copyright &y& Elsevier]

Dromaeosauridae is the sister taxon of the Avialae; thus, an investigation of dromaeosaur shoulder girdle musculature and forelimb function provides substantial information regarding changes in the size and performance of the theropod shoulder girdle musculature leading to avian powered flight. Twenty-two shoulder girdle muscles were reconstructed for the dromaeosaurid shoulder apparatus, based on phylogenetic inference, which involves the comparison of lepidosaurian, crocodilian and avian musculature, and extrapolatory inference, which involves a secondary comparison with functional analogues of theropods. In addition to these comparative methodologies, osteological correlates of shoulder musculature preserved in eumaniraptorans are identified, and comparisons with those of extant archosaurs allow these muscles to be definitively inferred in dromaeosaurids. This muscle reconstruction provides a foundation for subsequent investigation of differences in muscular attachment and function, based on scapulocoracoid morphology, across the theropod lineage leading to birds. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 146, 301–344. [ABSTRACT FROM AUTHOR]

Velociraptorine dromaeosaurid dinosaur teeth are reported for the first time from the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight, southern England. They represent the second record of the Dromaeosauridae in Britain and the first of this clade from strata of the British Wealden Group. [Copyright &y& Elsevier]

Postcranial skeletal pneumaticity (PSP) characterizes extant birds. This feature is related to a series of air sacs connected to the lungs and prolonged in diverticula that invade bones internally. Previous works revealed that PSP was present along the line to birds, being distinctive of pterosaurs and saurischian dinosaurs. PSP is profuse in the vertebral column of sauropods and theropods and was very studied in sauropods, although scarcely in non-avian theropods. Here we analyze the vertebral pneumaticity of the unenlagiine theropod Unenlagia comahuensis , including the observation through CT scans. Unenlagiinae is a clade of southern dromaeosaurid theropods that is closely related to birds. The vertebral centra have lateral pneumatic foramina (lpf) within fossae (commonly termed 'pleurocoels') in middle and posterior dorsals, an unusual feature among extant birds and many non-avian theropods. Another possibly pneumatic fossa stands out at both sides of the neural spine base, which is not present in dorsals of other non-avian theropods, except the unenlagiine Unenlagia paynemili. CT scans revealed camellate tissue in the centra, consisting of small chambers separated by thin trabeculae. Camellae are also observed in the unenlagiines U. paynemili and Austroraptor cabazai , other dromaeosaurids, other coelurosaurs, and some non-coelurosaurian tetanurans. Instead, more primitive groups generally have camerae (larger chambers separated by scarce thick septa). Thus, a possible trend of the vertebral inner pneumaticity types is observed throughout non-avian theropod evolution, as indicated by previous authors. This study provides valuable information that helps to clarify this trend, not only in dromaeosaurids but also throughout theropod evolution. • Pneumatic features of the dorsal vertebrae of Unenlagia comahuensis are studied. • Lateral pneumatic foramina are in the centrum from anterior to posterior dorsals. • CT scans revealed camellate tissue in the vertebral centra. • Camellae are also observed in other unenlagiines, such as Unenlagia paynemili. • This study increases the knowledge of pneumaticity of non-avian theropods. [ABSTRACT FROM AUTHOR]