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A new specimen, MAU-Pv-PH-453, comprising an isolated femur from the Plottier Formation (Coniacian-Santonian), northern Patagonia, is described here. Its characteristics, i.e., an anteriorly curved diaphysis; fused lesser and greater trochanters forming a trochanteric crest; a prominent medially directed head; and the absence of a fourth trochanter, allow us to identify it as belonging to a maniraptoran theropod. Among Patagonian maniraptorans, MAU-Pv-PH-453 shares similarities with alvarezsaurians, such as the absence of a posterior trochanter, a trochanteric shelf, and the fourth trochanter. However, in Patagonian alvarezsaurs, the lesser and greater trochanters are generally separated by a cleft. Notably, MAU-Pv-PH-453 exhibits some features seen in femora of parvicursorine alvarezsaurids, including a proximally projected trochanteric crest and an L-shaped profile in proximal view. However, MAU-Pv-PH-453 presents differences with parvicursorines, such as a knob partially separating the lesser and greater trochanters. Phylogenetically, MAU-Pv-PH-453 may have parvicursorine affinities, although its fragmentary nature might generate a bias in its phylogenetic position. Due to the lack of more diagnostic characters, MAU-Pv-PH-453 is assigned to Alvarezsauria indet. This material represents the second theropod record from the Plottier Formation and it could fill a temporal gap (between Coniacian and Santonian) in the record of Upper Cretaceous Patagonian alvarezsaurians. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Ganzhou Basin of Jiangxi Province, South China is among one of the richest egg fossil sites in the world and yields abundant exquisite egg clutches and embryonic eggs, especially in oviraptorosaurs. Hadrosaurian, troodontid, and potential dromaeosaurid egg fossils were also reported, though they were rare. All these reported eggs vary in morphology but have relatively large sizes. Here, we report a partial egg clutch with six complete small eggs from the Upper Cretaceous Tangbian Formation of Ganzhou City, Southeast China. The microstructure of the eggshell indicates that it can be assigned to Ovaloolithidae. Hence, we established a new ootaxon, Minioolithus ganzhouensis oogen. et oosp. nov. based on a unique combination of characters, including a small egg size, irregular egg arrangement, worm-like and nodular ornamentation, and a gradual boundary between two structural layers. The egg morphology and eggshell microstructure support it to be the smallest known non-avian theropod egg up to date. This discovery increases the diversity of dinosaur eggs in the Late Cretaceous and is significant for our understanding of the evolution of theropods in the Late Cretaceous. [ABSTRACT FROM AUTHOR]

Dinosaur fossils are commonly found in Brazilian Mesozoic strata, with teeth being frequently found in Cretaceous outcrops. Many studies have been made with the aim of reviewing the known diversity of Brazilian dinosaurs, mostly focusing solely on their palaeobiogeography. However, few tried to typify these body fossils in order to see which kinds were most prevalent in the fossil record. This study aims to count and identify all occurrences of non-avian dinosaur teeth (isolated or in situ) unearthed from Brazilian Cretaceous strata in order to objectively measure their representativity in the national fossil record. Our literature search showed that almost half of the dinosaur fossil record from the Cretaceous of Brazil is composed by teeth, those being particularly abundant in the Alcântara, Adamantina and Marília formations. Theropod teeth are more abundant in comparison to sauropod teeth, with spinosaurids, deinonychosaurs, and abelisaurids being amply found. Despite representing a large share of the Brazilian fossil record, dinosaur teeth have only recently been studied in depth, with many specimens being reassessed through the current identification methods. Other aspects besides primary taxonomic identification can also be further explored using the latest technologies on dinosaur teeth, allowing a deeper understanding of the palaeobiology of these reptiles. [ABSTRACT FROM AUTHOR]

Bolivia has an outstanding tetrapod ichnological record from the uppermost Cretaceous deposits plus a new Triassic locality recently reported. Here, we report a new ichnosite, the first for the Jurassic to earliest Cretaceous in the Castellón Formation (Tarija, Bolivia) bearing about 350 dinosaur tracks. With the exception of few tridactyl tracks, all exhibit sauropod characteristics. The exposed set consists of three mediumgauge, subparallel large quadrupedal trackways, with one trackway oriented in opposite direction to the other two. The best preserved trackway shows large pedes of about 95 cm and 75 cm in length and width, respectively. The trackmaker was about 3.80 m in height at the hip and walked at a speed under 5 km/h. Available evidence suggests that the producer of the more detailed trackway may be a member of non-Neosauropoda Eusauropoda, even if a titanosauriform producer cannot be discarded. Dozens of small-sized sauropod tracks, less than 15 cm in pes diameter, appear associated with two of the trackways. The distribution of these trackways provides elements to test gregariousness among trackmakers if a possible synchronism is accepted. Wanderings recognisable on the sediment surface suggest that they may collectively represent an ichnological example of herd behaviour. [ABSTRACT FROM AUTHOR]

The Tuchengzi Formation represents a Jurassic – Cretaceous boundary regional lithological unit that bridges the temporal gap between the Yanliao biota and the Jehol biota. Tetrapod tracks represent the most significant vertebrate fossil records in the formation, and can be employed to supplement the Late Jurassic fauna and palaeoecological data from northern China. Here, we present a re-analysis of the theropod tracks from the Luofenggou site in northern Hebei Province, utilising an additional 3D model and a locomotory analysis to provide further insights into the ecological context. A morphological analysis indicates that these tracks are more similar to Grallator than to the previously proposed Therangospodus. The latter is diagnosed by coalesced, elongate, oval digital pads lacking a separation in distinct phalangeal pads, whereas these are clearly defined in the presented Tuchengzi material. They can therefore be assigned to the widespread G. ssatoi ichnospecies from the Tuchengzi Formation, although they are longer and more variable in size than other G. ssatoi. A general consideration of speed-related locomotive parameters, trackway morphology, and superposition allows for the speculation of the existence of cooperative or predatory relationships between theropod trackmakers that were differentiated by size or stages of ontogeny, but had similar foot structures. [ABSTRACT FROM AUTHOR]

Sauropods were a successful group of herbivorous dinosaurs that colonised all continents throughout the Mesozoic. At first glance, the organisms in this group present a conservative shape of quadrupedal animals with elongated necks and tails. However, there was great diversification in the morphology of sauropods, which is still poorly understood in detail, especially during the Early Cretaceous. In this study, we describe a new ichnosite dated from the earliest stages of the Cretaceous of Brazil. The site includes a well-preserved trackway of a large sauropod dinosaur, with manus and pes prints, as well as tracks of theropods and indeterminate tetrapods. The sauropod trackway shows a unique set of characteristics that allowed the erection of a new ichnogenus and ichnospecies, Sousatitanosauripus robsoni igen. nov. et isp. nov. The probable trackmaker was a Titanosauriformes with a mosaic of basal and advanced features, bringing new insights into the diversity and evolution of the group. [ABSTRACT FROM AUTHOR]

The Upper Triassic – Lower Jurassic Stormberg Group, main Karoo Basin, is notably rich in diverse dinosaur trace fossils, particularly in the Roma Valley of western Lesotho. Here, we document in detail, for the first time, the Mokhosi ichnosite (Roma Valley), initially reported simply as preserving tridactyl tracks. Thirty-five pes tracks were identified, predominantly preserved as bipedal and quadrupedal trackways attributable to theropod and ornithischian trackmakers. Three distinct morphotypes consisting of pes or manus-pes pairs were assigned to Anomoepus, Eubrontes and tentatively to Kayentapus. Our Morphotype III, although comparable to Kayentapus, preserves quantitative and qualitative features distinct from other large southern African Kayentapus-like tracks, and possesses some characteristics that lean to an ornithischian affinity rather than theropod. Ultimately, the Mokhosi ichnosite contributes to the diverse ichnological record of the Roma Valley, which now includes 15 ichnosites that preserve Anomoepus, Eubrontes, Grallator, Kayentapus and Trisauropodiscus. Furthermore, this site provides essential data for refining our understanding of Early Jurassic ornithischians in Gondwana, which are minor components of the trace- and body-fossil records. [ABSTRACT FROM AUTHOR]

The Upper Cretaceous Cantwell Formation in Denali National Park and Preserve (DENA) preserves an abundant and diverse ichnofossil record of high latitude dinosaurs. Field-based investigations of the formation remain limited due to its wide areal extent and remoteness, leaving questions concerning its temporal and faunistic relationships to other units unaddressed. Here we describe the largest tracksite known in DENA and all of Alaska – a 7500 square metre outcrop of steeply dipping beds known as the Coliseum. The site exposes 66.3 metres of vertical section consisting of laterally extensive fine- to medium-grained sandstone, mudstone, calcareous shale, and bentonite. Vertebrate trace fossils include true tracks, transmitted tracks, natural casts, and trackways documented via handheld and UAV-assisted photogrammetry, enabling three-dimensional mapping of the site. Facies analysis reveals a depositional environment of crevasse splay and overbank deposits within a fluvial floodplain. U-Pb dating of bentonite collected from the site returned an age of 69.3 ± 0.9 Ma, improving the limited temporal constraints of the formation. We document several ichnotaxa, some new to the formation, representing ornithopods, ceratopsids, and large and small-bodied avian and non-avian theropods. The Coliseum provides a rare window into a high latitude, Late Cretaceous forested ecosystem deposited in a Greenhouse World. [ABSTRACT FROM AUTHOR]

Rebbachisaurids are a group of basal diplodocoid sauropods that diversified primarily in Gondwana between the early Lower Cretaceous and the early Upper Cretaceous. Their phylogenetic relationships are still under debate given the fragmentary and incomplete nature of its remains. Here, we provide a detailed description of the postcranial remains of Campananeyen fragilissimus gen. et sp. nov. from the Candeleros Formation (lower Cenomanian) of Neuquén Province, Argentina. Campananeyen presents notable features that allow it to be recognised as a new species by the presence of an underdeveloped crista prootica, paraoccipital process internally hollow and a fuse dorsal alar arm of the ilium. The phylogenetic analysis recovered this taxon as a basal rebbachisaurid closely related to Zapalasaurus, Sidersaura and the specimen from La Amarga Formation MACN-Pv-N 35. The new rebbachisaurid is recovered as the sister taxon of Sidersaura due the presence of procoelous posterior caudal vertebrae and dorsoventrally flattened posterior caudal centra. C. fragilissimus presents an extreme pneumatization of the sacral region with an autapomorphic dorsal alar arm of the sacral transverse processes. Finally, the phylogenetic analysis supports a South American origin for Rebbachisauridae and an early diversification to Africa and Europe by the Barremian-Aptian as previously suggested. [ABSTRACT FROM AUTHOR]

Currently, only birds have a pneumatic system, but in the past, this was common among several ornithodirans. Within Titanosauria, it was the saltasaurines that showed a high degree of postcranial pneumaticity. The objective of this work is analysing the extent of postcranial pneumaticity in saltasaurines and compare it with other derived titanosaurs. To carry out this work, presacral vertebrae, dorsal ribs, scapulae, coracoids and ilia of saltasaurines were analysed. The presacral vertebrae present a high degree of pneumatisation with a highly variable distribution of foramina, with some ‘foramina zones’, there is a homoplastic pattern of pneumaticity: presence of foramina connected to camellated tissue. With respect to the ilia, camellated tissue was recorded in all taxa. Instead, scapulae and coracoids, present camellated tissue in Saltasaurus and they cannot be pneumatised in Neuquensaurus. Comparing with other titanosaurs, we observe that there are ‘foramina zones’ for presacral and caudal vertebrae. It is also possible to establish that the pneumatisation of the dorsal ribs has a conservative pattern, not only in saltasaurines but also in the Saurischia clade, and the presence of pneumaticity in the ilia is frequent in the Lithostrotia and even outside, in rebbachisaurs. [ABSTRACT FROM AUTHOR]

Omission surfaces represent a gap in the sedimentary record on a particular environment, constituting an important tool for basin analyses. Nevertheless, not always these surfaces constitute key sequence-stratigraphic surfaces, and their correct interpretation is highly important for the recognition of genetically related strata. Documentation and interpretation of ichnological data from stratigraphic surface can refine the sedimentological model. The Puesto El Moro Formation (lower Upper Cretaceous) in the Austral-Magallanes Basin, southern Patagonia (Argentina), shows excellent examples of several omission surfaces stacked during a transgressive context associated with the beginning of the foreland stage. Each of these surfaces, interpreted as Tidal Ravinement Surfaces, contain Thalassinoides isp. and Sinusichnus isp., which represent opportunistic colonization by crustaceans into a predominantly firm substrate. In this case study, the vertical recurrence of substrate-controlled trace fossil suites is the result of high-frequency repeated coastal conditions during the transgression; the associated surfaces, which have limited lateral extension, have low potential for correlation at basin scale. [ABSTRACT FROM AUTHOR]

The cranial remains of the holotype of the Lower Cretaceous Bajada Colorada Formation (Neuquén, Argentina) Bajadasaurus pronuspinax and its associated 3D model are studied and compared herein. These materials comprise a complete braincase, skull roof and occiput, several periorbital elements, several palatal elements, a partially complete upper jaw and complete lower jaw, a partially complete functional dentition, and an indeterminate element. Three potential synapomorphies for the taxon, related to the temporomandibular articulation area, were recognised, two of them in the quadrate and one in the squamosal. Four potential synapomorphies for Dicraeosauridae were recognised, related to the braincase and the jaws, in the orbitosphenoids, prefrontals, maxillae and dentaries, and surangulars. The new information highlights the variability and similarities among Dicraeosauridae, allowing the reassessment of previously suggested skull configurations within the group, which are reinterpreted here a presenting stylised lower jaws, and suggests the presence of a cornified sheath on the rostral portions of the muzzle, such as the observed in other dinosaurian groups. [ABSTRACT FROM AUTHOR]

We report five new dinosaur track sites in Chaya County, about 120 km southeast of Changdu City. The track assemblages are dominated by sauropods (45 tracks), which have been identified tentatively as cf. Brontopodus. Also present are two thyreophoran trackways consisting of 13 tracks that show strong similarities with the ichnogenus Deltapodus, the potential trackmakers of which were probably stegosaurids. The sauropod tracks from the Chaya region are dominated by large tracks with different affinities if compared to those of the Changdu area. The isolated sauropod tracks from Changdu and Chaya regions show similar morphological patterns, but those from the Chaya region lack large scale tracks. This paper compares and discusses the known ichno and body fossil records of sauropods, theropods, and ornithischians from the Middle Jurassic of Yunnan, Sichuan, and eastern Tibet and their importance for our understanding of dinosaur faunas from this region. The absence of basal neornithischian records in the Yunnan and Changdu regions is likely a preservational bias but also an ecological pecularity cannot be completely excluded. The palaeogeographic position of the four sampled skeleton and track sites suggests the possible existence of a corridor through which faunal exchanges were taking place throughout the Jurassic. [ABSTRACT FROM AUTHOR]

The holotype of Sinosaurus triassicus is poorly preserved, and no previous research has focused exclusively on its anatomy. This research reports a new specimen recovered near the locality of the holotype of S. triassicus including a complete skull with mandible and 11 cervical vertebrae. Three newly identified traits are proposed to be unique of the species – (1) a vertical crest developed dorsoventrally from the ventral portion of the maxilla to the nasal crest; (2) ventral border of the antorbital fenestra formed mostly by the anterior process of the jugal; and (3) a fenestra between the nasal, the lacrimal and the prefrontal. This research provides new information on the cranial anatomy of this species as well as the genus Sinosaurus, offering more accessibility for later research concerning the evolution of early deriving neotheropods. [ABSTRACT FROM AUTHOR]

The mid-Cretaceous Sunjiawan Formation of western Liaoning Province, China has yielded a diverse of dinosaurs, yet without records of theropods. Recently, four isolated dinosaur teeth were discovered from the Sunjiawan Formation in Shuangmiao, Liangshuihe, Beipiao, Liaoning, China. They can be assigned to Tyrannosauroidea, Titanosauriformes and Hadrosauroidea based on morphological features. The tyrannosauroid tooth represents the first fossil record of Theropoda in the Sunjiawan Formation. The titanosauriform tooth is provisionally attributed to Borealosaurus considering that they are from the same horizon and locality. The hadrosauroid teeth represent a distinct taxon from Shuangmiaosaurus, the only known hadrosauroid from this formation. These findings increased the diversity of dinosaurs of the Sunjiawan Formation from three taxa to five. [ABSTRACT FROM AUTHOR]

A pathological metatarsal of the early-branching megaraptoran Phuwiangvenator yaemniyomi from the Lower Cretaceous of Thailand is here studied. It was CT-scanned and compared with pathology in other dinosaurs and living animals. The result shows that the palaeopathology in Phuwiangvenator was a traumatic fracture, specifically a greenstick fracture, based on the incomplete breakage of the bone, which occurred only on one side and twisted or distorted in the opposite direction to the force that caused the pathology. The cause of the fracture was possibly by accidentally hitting or kicking hard material, fighting, or falling to the ground. Phuwiangvenator was probably an adolescent when it was injured and survived the incident. This is the second report of a greenstick fracture in Theropoda after Akansaurus fridayii; the first detailed analysis of palaeopathology in Megaraptora; and the first record and detailed description of palaeopathology in non-avian theropods in Southeast Asia. [ABSTRACT FROM AUTHOR]

A newly discovered dinosaur tracksite in the Middle Jurassic Xietan Formation of the Zigui Basin, is the first reported from Hubei Province, China. Access to the site is difficult due to the steep inclination (~60°) of the track-bearing beds. The tracks are poorly preserved and occur in a fragmented mudstone substrate. However, it is possible to identify a sauropod trackway and isolated tridactyl (theropod) tracks, suggesting a saurischian dominated ichnofauna. The preserved sauropod trackway falls into the range of a typical wide gauge sequence and, together with the overall shape of the imprints and low heteropody, points to the ichnogenus Brontopodus. The tracks are of relatively small size and can possibly be attributed to juveniles of a large species or, alternatively, to adults of a small species of eusauropods. The tridactyl tracks are incomplete and cannot be assigned to a distinct ichnotaxon with certainty. [ABSTRACT FROM AUTHOR]

Here, we describe a pathological sub-adult theropod dinosaur from the Late Jurassic Morrison Formation in Dana Quarry, Wyoming, U.S.A. It exhibits multiple pathologies, involving three dorsal vertebrae, the right scapula and coracoid, and apparent pathology of the left scapula. The fourth dorsal vertebra has four irregularly shaped growths on the vertebral arch. The eighth and ninth vertebrae are fused. The scapulocoracoid joint has an obvious deformity. The distal part of the right scapula is more rounded than normal. The left scapula has a depression on the lateral blade. These pathologies can be identified as follows: the fourth dorsal vertebra is possibly neoplastic or exhibiting compensatory hyperplasia; the eighth and ninth vertebral and the right scapular pathology are consistent with spondyloarthropathy. Diagnoses considered for the left scapula pathology are infections, trauma or unknown. The animal survived the pathologies, which are unlikely the cause of its death. This specimen represents the first known occurrence of spondyloarthropathy in a theropod. [ABSTRACT FROM AUTHOR]

A well-preserved paravian manus was described from the Jehol Biota of western Liaoning, China. This specimen was inferred as an early-diverging troodontid and reveals new morphological details of the troodontid clade, such as both ends of phalanx II-1 and phalanx II-2 asymmetrical, phalanx II-1 and phalanx III-3 twisted medially, the ventral side of the distal end of phalanx II-2 flat, and the proximal articular surface of phalanx III-1 non-trochoid. The range of motion of this manus was examined based on the CT data of the bones, showing that the range of flexion of this troodontid manus is relatively large while the range of extension is relatively limited, which is consistent with the tendency of the decrease in the manual extension capabilities from early-diverging theropods to maniraptoriforms. [ABSTRACT FROM AUTHOR]

An incomplete albeit well preserved tooth from the Late Jurassic Tacuarembó Formation (Uruguay) shows a character combination only found in abelisaurid theropods, i.e. irregular enamel, hooked distal denticles, interdenticular sulci, lanceolate cross-sectional shape, and straight distal border. Its referral to Abelisauridae was tested via a phylogenetic analysis, with the Uruguayan taxon deeply nested within the clade. This is the first record of abelisaurids in Uruguay and one of the few Jurassic records of the group worldwide. Abelisaurids occur together with ceratosaurids and megalosaurines in the Tacuarembó Formation, revealing a rich Late Jurassic theropod assemblage. [ABSTRACT FROM AUTHOR]

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 validity of the second species has been challenged, and all carcharodontosaurid material from the KKCA has been referred uniquely to the former species. Here, we describe a new theropod cranial material from the KKCA which is referred to Carcharodontosauridae, including one partial maxilla which shows a morphology distinct from that of C. saharicus. We review the arguments used to interpret Sauroniops holotype as an immature individual of Carcharodontosaurus and show that they were based on non-homologous comparisons and on the misinterpretation of the original description of S. pachytholus: The latter is confirmed to be a valid taxon, distinct from C. saharicus and with an inferred body size comparable to the largest carcharodontosaurids. The presence of more than one giant carcharodontosaurid species in the Cenomanian of Morocco recalls the carcharodontosaurid diversity from penecontemporary units from Argentina. [ABSTRACT FROM AUTHOR]

The early radiation of dinosaurs was an evolutionary event characterized by distinct episodes. While the earliest unequivocal records are from Carnian strata and relatively well-documented, the subsequent moment of dinosaur radiation is poorly studied. The fossil record of early Norian dinosaurs from Brazil provides one of the best samples regarding the dawn of the “Prosauropod Empire”. In the present study, we describe the first occurrence of Macrocollum itaquii outside its type locality and discuss its biostratigraphic implications. This dinosaur is of particular interest due to its significance as the oldest sauropodomorph with an elongated neck, expressing the typical body plan seen in post-Carnian sauropodomorphs. The new specimen consists of a partial posterior autopodium, sharing anatomical features exclusively with M. itaquii among sauropodomorphs. The presence of this unaysaurid at the “Boi da Guampa Torta” site allows the biostratigraphic correlation with the “Wachholz” site. According to the phylogenetic affinities of M. itaquii (which is more derived than Pampadromaeus barberenai and Bagualosaurus agudoensis), both fossiliferous sites are younger than the “Várzea do Agudo” site. Nevertheless, further specimens are necessary in order to determine the position of the sites with M. itaquii in relation to the other surrounding outcrops (i.e., Siriusgnathus-bearing outcrops). [ABSTRACT FROM AUTHOR]

Brachytrachelopan is a dicraeosaurid sauropod that comes from the Jurassic of Argentine Patagonia. With the purpose to infer different palaeobiological traits (e.g., ontogenetic stage, growth dynamics, temporal correlation between morphological and anatomical parameters of maturation), we perform an osteohistological study on different postcranial elements from the holotype individual, including axial (i.e., cervical hemispinous process, dorsal ribs) and appendicular (i.e., femur) bones. The absence of a distinct external fundamental system indicates that the individual died before full body size achievement (i.e., somatic maturity). Furthermore, although not conclusive, the histological data suggest that despite its body size, which is comparable with fully grown individuals of other dicraeosaurid taxa, the individual also corresponds to a sexually immature specimen. Predominance of highly vascularised fibrolamelar with only a cyclical growth mark (CGM) in the outer cortex of the femur reveals a sustained, accelerated growth, typical feature of neosauropod dinosaurs. The external anatomy (i.e., neurocentral sutures are visible in presacral vertebrae) is consistent with histological data, since both indicate some degree of immaturity. Dorsal ribs are best elements to estimate age. The new evidence reinforces the hypothesis that mechanical forces were higher in the anterior edge of cervical hemispinous processes, although, these findings do not support the presence of horn cores or interspinous ligament system in the neck of Brachytrachelopan. [ABSTRACT FROM AUTHOR]

Comprising more than 350 dinosaur footprints and at least 38 trackways, the TY tracksite described herein is located close to the border of NW Lesotho, near Teyateyaneng (TY), and is probably identical to the site originally mentioned by Dornan in 1908. The tridactyl footprints are exposed as natural casts on a cliff overhang and a fallen block at the base of the cliff in the uppermost Elliot Formation (Sinemurian, Lower Jurassic). High-resolution photogrammetry and zoom lenses facilitated the detailed ichnological documentation of the otherwise inaccessible overhang. The tracks vary greatly in morphology, likely due to moisture fluctuations in the tracking surface during their formation. Repeated wetting and drying of the track-bearing sediment is indicated by the cross-cutting relationship of the several generations of desiccation cracks and tracks. Two footprint size classes can be distinguished, with the smaller class being Grallator-like and the larger class being assignable to Eubrontes. All tracks are likely attributable to bipedal, small to moderately large theropod dinosaurs that roamed the drylands of the region c. 190 million years ago. Our ichnological account turns this aesthetic TY footprint site into an apt geoheritage destination with scientific and educational value for all. [ABSTRACT FROM AUTHOR]

The relatively large (1,600 m2) Jeo-ri dinosaur tracksite from the Lower Cretaceous Sagok Formation in the Uiseong County area in Gyeongsangbuk-do (North Gyeongsang Province) was the first dinosaur tracksite designated as a Korean Natural Monument (Number 373). However, it has never been described in any detail. It is shown to reveal more than 380 footprints attributed to theropods, sauropods and ornithopods. The trackways show a preferred orientation to the north and northwest with some similarly sized ornithopod trackways suggesting gregarious behaviour. A smaller tracksite from the Mancheon-ri site, representing the Sagok Formation also reveals theropod, sauropod and ornithopod trackways. These include trackways of two small ornithopods (footprint lengths ~9.9-11.5 cm) that indicate deceleration while transitioning from bipedal to quadrupedal progression. One trackway shows rare evidence of pausing to 'stand' and leave 'side-by-side' footprints. The Sagok Formation is considered correlative with the Haman Formation which is well known for its dinosaur tracksites in Gyeongsangnam-do (South Gyeongsang Province). This correlation underscores the importance of understanding the remarkable abundance and spatiotemporal distribution of dinosaur tracks in the Lower Cretaceous of Korea. [ABSTRACT FROM AUTHOR]

Recently, a new fossil site containing microvertebrate remains has been discovered in the upper part of the Nenjiang Formation (early Campanian) in the Songliao Basin, northeast China. Five isolated theropod teeth were discovered. The teeth were analysed based on morphological traits and the results showed that they correspond to the clades of Troodontidae, Dromaeosauridae and ?Tyrannosauridae. One dromaeosaurid tooth can be furtherly assigned to Dromaeosaurinae. It is the first discovery of theropod teeth from the Nenjiang Formation, also the first record of the Dromaeosaurinae from China. This study extends the known geographic range of these clades of theropods. The new materials also expand knowledge of the terrestrial ecosystem during the Late Cretaceous of the Songliao Basin. [ABSTRACT FROM AUTHOR]

Trace fossils offer a great potential to enhance our understanding of the rise of dinosaurs and their interactions with the environment. Here, we report a Rhaetian theropod footprint found in the Shazhenxi Formation of the Zigui Basin, representing the stratigraphically oldest dinosaur track recorded from the Middle Yangtze region and has great significance for understanding the Late Triassic theropods and their distribution across East Asia. The tridactyl track is assigned to cf. Eubrontes isp. and shows a similar morphology with some tracks from the Sichuan Basin, indicating that Eubrontes had a wider spatial distribution in the Upper Triassic than previously thought. This work highlights the great interest and importance of palaeoichnological prospecting in the Triassic deposits of the Zigui Basin. [ABSTRACT FROM AUTHOR]

Spinosaurid dinosaurs show a wide geographical and temporal distribution, being present in Gondwanan and Laurasian landmasses, at least, during the Lower Cretaceous and the Cenomanian. European spinosaurids are more diverse than previously thought with five, and probably six, currently recognised genera. The revision of CPI 477, a fragment of a left maxilla from the Lower Cretaceous of La Rioja (Spain) previously assigned to Baryonyx, demonstrates that this specimen cannot be referred to this genus and likely belongs to an indeterminate baryonychine closer to Baryonyx than to Suchomimus. CPI 477 exhibits a tooth replacement process comparable to that of other theropods and, besides, similar to other large theropods, two replacement teeth could simultaneously be developed in the same alveolus, partly explaining high replacement ratios and the overabundance of spinosaurid teeth in some fossil sites. Furthermore, the Oxalaia maxilla shares the anteriorly located external naris with Irritator and baryonychine spinosaurids, which differ from the more retracted ones in African spinosaurines. Finally, in addition to the previously noticed differences between Baryonychinae and Spinosaurinae, the paradental groove of African spinosaurines and Oxalaia differs from that of baryonychines in being sinusoidal instead of straight. [ABSTRACT FROM AUTHOR]

Predators affect prey by killing them or inducing changes in their physiology and behaviour through a fear effect associated with predation risk. In birds, perceived predation risk influences reproductive decisions, such as the reduction of parental investment in offspring during both egg production and nestling rearing. Visual and vocal cues of predator presence have been widely used to test the direct effects of predation risk. However, few studies have examined the indirect cues of predator activity such as dead avian prey or their remains. In this study, for the first time, we experimentally studied whether piles of feathers, simulating the remains of avian prey, induce changes in the reproductive decisions of adult birds. Before and during egg laying, great tit, Parus major, pairs were exposed to piles of bright down and cover feathers from domestic goose (treatment), woodchips (procedural control), or were not exposed (control). Our experiment affected maternal investment in individual eggs, but did not influence other reproductive parameters. Females from the treatment group laid larger and more asymmetrical (pointed) eggs than control females. Moreover, females from the procedural control group laid larger eggs than those from the control group, but without differences in egg shape. However, the eggs from the treatment and procedural control groups did not differ. This indicates that great tit females can perceive feathers and woodchips as informative cues, such as potential predation risk or habitat suitability, or as novel items in the environment. Importantly, females respond to such cues by changing their maternal investment in eggs, which may result from an adaptive mechanism aimed at increasing offspring fitness in the face of specific environmental conditions experienced by a female. Our study contributes to the understanding of how female songbirds adjust their maternal reproductive investment in response to publicly available social and environmental cues. [ABSTRACT FROM AUTHOR]

Although osteohistology has proven to be useful to discern several palaeobiological traits and systematics in non-avian dinosaurs, the bone microstructure of several groups (e.g., abelisaurid theropods) is still poorly documented. Here, we provide a microstructural description of different bones (a cervical epipophysis, three dorsal ribs, three grastralia, and the left femur) of the type specimen of the abelisaurid Aucasaurus garridoi, its ontogenetic stage and compare its growth with other theropods, especially abelisauroid taxa. The cortical bone is mostly composed by fibrolamellar bone tissue composed of a woven-fibred matrix. Secondary remodelling varies among the different elements. The compacta of the rib shows eleven growth marks (with an additional seven in the external fundamental system), implying that the specimen was at least eleven years old and had reached somatic maturity when it died. The presence of lines of arrested growth/annuli supports a cyclical growth strategy, as in Niebla, Quilmesaurus, and Abelisauridae indet. MMCh-PV 69. All these abelisaurids indicate that the maturity based on cyclical growth marks spacing is not reliable, due to considerable variability of this parameter within a single element. This study represents the first intensive osteohistological investigation for an Abelisauridae member, providing new information on palaeobiological traits of this clade. [ABSTRACT FROM AUTHOR]

Theropods comprise a successful group of mostly predatory dinosaurs with varied growth rates that colonized all continents. Much research has addressed the histology of the Global North's Mesozoic populations, especially coelurosaurians and allosauroids. However, little has been done to understand the histological patterns of the Gondwanan populations, especially abelisauroids. Previous studies detected disparate (parallel-fibered or fibrolamellar) bone profiles between noasaurids and abelisaurids but did not include broader quantitative analyses. Here we describe the femoral histology of a mid-sized abelisaurid from the Upper Cretaceous Serra da Galga Formation, Bauru Group, Southeast Brazil. Despite the harsh semiarid paleotropical context, our specimen shows a growth rate more similar to the Patagonian abelisaurids, challenging a previous hypothesis on environmental pressure selecting taxa with lower growth rates and parallel-fibered bone tissue. We also bring data to bear from several taxa to test the hypothesis of tissue differentiation within abelisauroid clades. Our logistic regression and correlation analyses show that the variation in histology in noasaurids and abelisaurids can be explained by body size and phylogeny when considering fibrolamellar tissue, but not parallel-fibered tissue. A decrease in growth rate through the deposition of parallel-fibered bone tissue may be an example of evolutionary convergence between noasaurids and some small-bodied sauropods. [ABSTRACT FROM AUTHOR]

Small-bodied theropod dinosaurs are rare on southern landmasses but have been known from India for a century. Excavations by Charles Matley and Durgansankar Bhattacharji in uppermost Cretaceous sediments at Bara Simla, central India in 1917–1919 recovered small theropod vertebral and limb elements originally interpreted as coelurosaurians and separated into at least three species (Compsosuchus solus, Laevisuchus indicus, Jubbulpuria tenuis) based on features that can now be attributed to their serial position in the vertebral column. The comparatively recent discoveries of Noasaurus leali and Masiakasaurus knopfleri from similar-aged rocks in South America and Madagascar, respectively, and advances in basal theropod systematics led to a revised interpretation of most small-bodied Indian theropods as noasaurid abelisauroids. Here we review and redescribe Laevisuchus, Jubbulpuria, and Compsosuchus, including several elements that until now were thought lost, and describe a new partial noasaurid dentary from central India. The dentary bears the characteristic procumbent dentition of Masiakasaurus, which apparently is absent in Noasaurus. Likewise, cervical vertebrae of Laevisuchus more closely resemble those of Masiakasaurus than those of Noasaurus. Despite these similarities, phylogenetic analyses indicate that the balance of character data supports the Indian noasaurid species outside the sister-taxon pairing of South American and Malagasy species. Bones of small-bodied theropods have been recovered exclusively from the youngest Mesozoic localities in India (e.g., Pisdura, Bara Simla); to date they have not been reported from the slightly older localities in western and central India, from southern Indian sites in the Cauvery Basin, nor from the Vitakri Formation of Pakistan. [ABSTRACT FROM AUTHOR]

Nine morphotypes of coprolites, including Heteropolacopros texaniensis, Liassocopros isp., Hyronocopros amphipola, Eucoprus isp. 1, Eucoprus isp. 2, Morphotype 1, Morphotype 2, Morphotype 3, and Morphotype 4, are distinguished from the basal Late Cretaceous (Lower Cenomanian) of the 'Continental Intercalaire' deposits at Gara Samani (Sahara, southern Algeria). This coprofauna is the first to be identified, described and illustrated from the Mesozoic of Algeria. It adds new information on the trace-fossil assemblages previously reported from the Cretaceous localities of North Africa. The Gara Samani coproassociation marks the youngest occurrence of the ichnogenera Heteropolacopros and Hyronocopros. Most coprolites were produced by ichthyophagous carnivores, such as crocodiles, theropods (Spinosaurus) and different kinds of fish. [ABSTRACT FROM AUTHOR]

The Jurassic and Cretaceous tetrapod track record in China has incrementally expanded due to the discovery of small sites in widely dispersed geographical locations, which often lack body fossils. Many of these are theropod dominated tracksites where, despite morphological variation, identification of ichnotaxa is difficult at low taxonomic levels (i.e., ichnogenus/ichnospecies assignments). Here we report on an Early to mid-Cretaceous site from the Mawu Formation (Zhagang Group) in Guangdong Province, China, a region thus far scarcely known from dinosaur fossils. The new site yielded three different morphotypes tentatively labelled as a Paracorpulentapus-eubrontid-grallatorid assemblage. It is noted that similar assemblages have been identified from Cretaceous deposits in Sichuan and Anhui provinces of China. [ABSTRACT FROM AUTHOR]

Monospecific assemblages of non-avian theropod tracks are relatively rare in the Cretaceous of Korea, where assemblages dominated by the tracks of diverse tetrapods (birds, sauropods, ornithopods, and pterosaurs) are well known and widely distributed in the Haman and Jindong formations (Hayang Group). To date, few high-density assemblages of theropod tracks have been documented. A Haman Formation site on Adu Island reveals a small high-density assemblage of Grallator tracks (~29 tracks/m2). The tracks, which indicate registration on a sandy substrate infused with microbial mat, are indistinguishable from Grallator tracks known from a few other Lower Cretaceous sites in China and east Asia. Early and Middle Jurassic Grallator-dominated assemblages are common in east Asia, and persist into the Late Jurassic- Early Cretaceous (Neocomian) transition in China, where they are typically only associated with sauropodomorph tracks. Post-Neocomian (Aptian-Albian) Cretaceous assemblages from Korea are much more diverse, and characterised by tracks of sauropod and ornithopod dinosaurs, non-avian and avian theropods (birds), pterosaurs and other tetrapods. Post-Neocomian assemblages dominated by theropod tracks, are rare and no large monospecific grallatorid assemblages are currently known. [ABSTRACT FROM AUTHOR]

Dinosaur fossils of the Lower Cretaceous (Aptian–Albian) Eumeralla Formation (Otway Basin) of Victoria provide insights into the faunal and ichnofaunal diversity of southern hemisphere high latitude dinosaurs during the initial separation of Australia from Antarctica. To date, at least eight dinosaur fossil locations have been reported from this formation. In this paper, we describe a new tracksite locality along the coastline of Wattle Hill that represents the most westerly occurrence of dinosaur fossils in the state. Some of the Wattle Hill prints resemble tracks attributed to ornithopodan trackmakers from neighbouring tracksites of the Eumeralla Formation (Knowledge Creek, Browns Creek), while others resemble bird prints. The site also preserves a large non-avian theropod footprint that resembles Megalosauropus prints from the Lower Cretaceous (Valanginian–Barremian) Broome Sandstone, Western Australia that if correct, extends the temporospatial range of this ichnogenus. The Wattle Hill tracks vary in their erosion between and within tracksites, from a natural mould (concave epirelief), transmitted tracks, possibly penetrative tracks and infilled reliefs that resemble (but differ from) natural casts. With the constant weathering of the Eumeralla Formation exposures, it seems likely that additional dinosaur tracks fossils will be discovered with continued Victorian coastal explorations. [ABSTRACT FROM AUTHOR]

The Middle Jurassic lower Shaximiao Formation in Sichuan Province of south-western China has yielded a diverse terrestrial vertebrate fauna dominated by sauropod dinosaurs. However, many of these sauropods lack detailed descriptions or explicit phylogenetic diagnoses. Here, we present a comprehensive redescription of Dashanpusaurus dongi, a species of sauropod found only in the lower Shaximiao Formation. We define the revised autapomorphies of the species as follows: neural canals are sub-square in anterior dorsal vertebrae; the presence of a thin accessory lamina that contacts the prezygodiapophyseal and paradiapophyseal laminae of the middle dorsals, forming an angle of 75° to the horizontal; and four ridges on the anterodistal edge of the humerus. Often considered part of the epipophyseal-prezygapophyseal lamina, a strut invades the spinodiapophyseal fossa in the cervical and anterior dorsal vertebrae. Anatomical comparisons indicate that this feature was widespread among early-diverging Middle Jurassic eusauropod lineages. This comparative anatomical data provides an opportunity to revisit the phylogenetic position of Dashanpusaurus and the relationships of the neosauropod clade. Recovered as a macronarian, a better understanding of Dashanpusaurus dongi will allow for clarification of the origin, early evolution, and palaeogeographical distribution of neosauropods. This study also suggests that the diversity and dispersity of the neosauropod clade occurred much earlier than previously realized. [ABSTRACT FROM AUTHOR]

Skorpiovenator bustingorryi is a derived abelisaurid theropod represented by a fairly complete skeleton from the Late Cretaceous sedimentary beds of north-western Patagonia. Although some features were described in the original paper, mainly related to the skull, the appendicular anatomy remains undescribed. The aim of the present contribution is to provide a detailed description and analysis of the available appendicular bones, including comparisons with other ceratosaurian theropods close to Skorpiovenator. In this way, new autapomorphies emerged to further distinguish Skorpiovenator from its relatives. Furthermore, a comprehensive phylogenetic analysis was performed and several characteristics of the hind limb, in particular some of the autopodium, resulted in the identification of new apomorphic traits for Ceratosauria and Abelisauridae. These features might prove to be useful for future phylogenetic analyses and may help to resolve the still confusing and debated internal relationships of abelisaurid theropods. [ABSTRACT FROM AUTHOR]

An almost complete dinosaur femur found in the Baynshire Formation (late Cenomanian to Santonian; Mongolia) in 1963 during the Polish–Mongolian Paleontological Expeditions is described here for the first time. The morphology of the femur and bone histology suggest that the specimen was a representative of the Titanosauriformes, the predominant sauropod clade during the Cretaceous. Bone tissue exclusive to this clade, modified laminar bone that indicates a reduced growth rate, is identified in the thin sections taken from the femur. Based on its bone histology, the already ca. 20-meter-long specimen appears to be a subadult. This specimen achieved a significantly larger size compared with other Titanosauriformes with modified lamellar bone at a similar growth stage. [ABSTRACT FROM AUTHOR]

The Lower to Middle Jurassic Kota Formation of India has yielded abundant yet disarticulated skeletal remains attributed to the basally diverging sauropod Kotasaurus yamanpalliensis. The hypodigm of Kotasaurus yamanpalliensis includes four ellipsoidal elements that we identify as tail clubs, based on morphological similarities to tail clubs attributed to two basal sauropods from China: Shunosaurus lii, for which a fully articulated tail series was recovered, and Omeisaurus tianfuensis. Detailed comparison of the Chinese and Indian tail clubs suggests that they are composed of up to three individual elements that fuse in adulthood. Computed tomography of the Indian tail clubs reveals their internal structure, which shows incremental growth lines as well as other features whose origin and function remain unknown. The Indian and Chinese tail clubs share a similar temporal range (Early to Middle Jurassic) and similar morphologies, which raises the question of whether sauropod tail clubs evolved once, multiple times, or were gained and then lost within basally diverging members of Sauropoda. We describe four new characters to reflect the morphological constituents of sauropod tail clubs known to date. [ABSTRACT FROM AUTHOR]

Ichnofossils are a useful tool in determining some aspects of the palaeoecology from past ecosystems, being often used as evidence of interactions between extinct organisms. In this paper we describe tooth traces found in UFRJ-DG 705 R, a fragmentary sauropod epiphysis, from the Presidente Prudente Formation, Bauru Group. We infer that these traces were made by a small to medium-sized crocodyliform, most likely an itasuchid, in a possible act of necrophagy. This new record of tooth traces in the Bauru Group showcases important evidence concerning trophic relations between sauropods and crocodyliforms in this locality during the Late Cretaceous. [ABSTRACT FROM AUTHOR]

A new genus and species of middle size bunodont artiodactyl (Mammalia), Erlianhyus primitivus, is established based on a partial maxilla with P3–M3 from the lower middle Eocene Irdin Manha Formation, Erlian Basin, Nei Mongol, China. Erlianhyus is characterised by a low tooth crown, bunodont cusps, a protocone smaller and lower than the paracone on P4, a large metaconule, reduced paraconule, no hypocone and styles on M1–3, and weak crista between the main cones on the upper cheek teeth. Erlianhyus is more similar in dental morphology to the Asian Myanmarius, Myaingtherium and Siamotherium rather than to other artiodactyls. Our cladistics analysis shows that Erlianhyus is positioned outside of the anthracotheriid-suoid-dichobunoid clade and is located more basally within the Artiodactyla, so now it is not referred to any known family or superfamily in artiodactyls. [ABSTRACT FROM AUTHOR]

The age of Yunnanosaurus youngi, a non-sauropod basal sauropodomorph, was reported as the Middle Jurassic. However, no basal sauropodomorphs have been reported worldwide in the Middle Jurassic previously, and only one clade of sauropodomorphs, Sauropoda, existed in the Middle Jurassic and became extinct by the end of the Cretaceous. Here, we further investigated the locality and its horizon of Yunnanosaurus youngi in Jiangyi, Yuanmou County, Yunnan Province, China. We found the species horizon is actually from the Lower Jurassic Fengjiahe Formation, and its age is probably Pliensbachian. Furthermore, the three known Yunnanosaurus-bearing horizons in Chuxiong, Yunnan can be correlated lithostratigraphically. Abbreviations FJHF: Fengjiahe Formation; LFF: Lufeng Formation; P: profile; TJB: Triassic-Jurassic boundary; YNOQ: quarry of Yunnanosaurus youngi; ZHF: Zhanghe Formation. [ABSTRACT FROM AUTHOR]

Despite being poorly known from limited skeletal remains as teeth and a few postcranial material, spinosaurid remains have been reported from two different Lower Cretaceous localities in Brazil, with three officially proposed taxa up to now: Angaturama, Irritator and Oxalaia. Here, we report the first record of a spinosaurid pedal ungual from the Itapecuru Formation, Parnaíba Basin, Lower Cretaceous rocks of Maranhão State. The specimen retains a quite flat ventral surface that is proportionally almost two times broader than its proximal depth, which is a feature also found in Spinosaurus. Moreover, size inferences are made for this immature specimen. [ABSTRACT FROM AUTHOR]

The morphology of the neurovascular canal in the jaw has been analysed in several fossil reptiles, including theropod dinosaurs. However, the details of the neurovascular canal in the dentary of theropods have not been fully elucidated. In this study, we described the well-preserved dentary of Tyrannosaurus rex, analysed the morphology of the neurovascular canal in the dentary using computed tomography techniques, and compared its distribution pattern with other dinosaurs and extant crocodiles. The results show that the neurovascular canal in the dentary of Tyrannosaurus exhibits a rather complex branching amongst the sampled dinosaurs, and that the complexity is comparable to that of extant crocodilians. The complexity of the canal branching is likely related to the high tactile sensitivity of the dentary, suggesting that the jaw tip of Tyrannosaurus may have played an essential role as a sensitive tactile sensor. [ABSTRACT FROM AUTHOR]

Shunosaurus is a small eusauropod from China. It is characterised by solid cervical and dorsal vertebral centra without complicated pneumatic structures, platycoelous or amphicoelous middle and posterior vertebrae and a lack of pubic foramen in adult individuals. Although many Shunosaurus individuals have been discovered, the ontogenetic characteristics of its long bones and bone tissues are not very clear and the existing description of the postcranial skeleton is relatively rudimentary. The new well-preserved and the smallest Shunosaurus specimen discovered in Yunyang, Chongqing, China, provides good material for solving these problems. The radial distal breadth is more than twice the minimum midshaft breadth, and the fibular distal end is twice as wide as the midshaft, while these ratios are all smaller in adult specimens. The lateral trochanter is undeveloped. This individual does show a pubic foramen. The degree of vascularisation of the bone tissue in the juvenile bone tissue is higher for adults. There are no arrested growth lines and peripheral rest lines in the compact bone, indicating that body size still increases slowly after maturity. The discovery of this new material expands the distribution range of Shunosaurus in China. [ABSTRACT FROM AUTHOR]

Dinosaurs produced a broad range of different types of eggs. Some of which have no analogue among those laid by living reptiles and birds. Eggs with shell units branching into an unusual labyrinth associated with a complicated pneumatic system were assigned to the parataxonomic oofamilies Faveoloolithidae and Dendroolithidae. While numerous new related ootaxa were described recently, many biological aspects as well as the identity of their producers have remained unknown or unresolved. Here, we provide the first experimental evidence that some mid-sized dendroolithid eggs were laid by a therizinosauroid theropod. We scanned and studied two faveoloolithid eggs. One of them contains putative embryonic remains that correspond to an articulated cranial skeleton exhibiting rather reduced antorbital region/opening similar to that in titanosaurian embryos. Another faveoloolithid egg exhibits unusual bending of the uninterrupted shell; we discuss three alternative interpretations: natural deformation, pathology and pliability, to explain this unusual phenomenon. [ABSTRACT FROM AUTHOR]

The smallest non-avian theropods have often attracted attention of palaeobiological and ichnological research. Here, we describe a diminutive tridactyl track (10.2 mm in length) from the Lower Jurassic Ma'anshan Member of the Ziliujing Formation, Wuli site, Sichuan Province, China. The Wuli specimen may be the smallest theropod track in the world. However, as with other diminutive tracks, it remains unresolved if it was made by a juvenile or by a small species. The body length of the trackmaker is estimated at 12 cm, equivalent to the size of a modern sparrow. Possibly the track belongs to a juvenile suggesting precociality or superprecociality. [ABSTRACT FROM AUTHOR]

Aeolosaurus is a late Cretaceous Titanosaur genus with two species discovered in Argentina and one in Brazil. Although the allocation of the Argentinean Aeolosaurus seems unequivocal, that is not the case for the Brazilian species Aeolosaurus maximus since several authors questioned its positioning into this genus, based on both anatomical and phylogenetic data. The revision of the diagnosis of Ae. maximus, with the proposition of a new autapomorphy, corroborates the anatomical uniqueness and our phylogenetic analysis stresses that the relation of Ae. maximus to the Argentinean Aeolosaurus is uncertain. Based upon that, we propose a new genus, Arrudatitan, to accommodate the Brazilian taxon. [ABSTRACT FROM AUTHOR]