Vertebrate Fossil Record Research Articles

The ecology of Australopithecus anamensis in the early Pliocene of Kanapoi, Kenya

Australopithecus anamensis is a pivotal species in human evolution. It is likely to be the direct ancestor of Australopithecus afarensis and the species that may have given rise to the Homo and Paranthropus lineages. It had a suite of adaptations for habitual bipedalism and a diet that differed from that of earlier hominin species. Under what environmental and ecological conditions did this suite of adaptations arise? The early Pliocene site of Kanapoi in the Lake Turkana Basin of Kenya has the largest sample of A. anamensis in eastern Africa and a rich record of fossil vertebrates. Most Kanapoi fossils are chronologically well constrained by radiometrically dated tephras between the ages of 4.2 and 4.1 million years ago. Sedimentological, isotopic, and faunal data indicate that the environments of Kanapoi during the early Pliocene had a complex range of vegetation types that included closed woodlands, shrubs, and grasslands near a river (for most of the sequence) or lake. These were dynamic landscapes that could shift rapidly from fluvial to lacustrine conditions, and then back. Australopithecus anamensis shared its environments with at least 10 species of very large herbivores, which undoubtedly played a major role in modifying the landscape by opening wooded areas and providing pathways for bipedal hominins. Hominins may have competed for terrestrial resources with abundant suids (Nyanzachoerus and Notochoerus) and for arboreal resources with monkeys (Parapapio being the most common cercopithecid). Kanapoi had a formidable group of predators that included a very abundant species of hyena (Parahyaena howelli), two sabre-tooth felids (Dinofelis and Homotherium), a giant otter (Enhydriodon cf. dikikae), and three species of crocodiles. Various measures of abundance indicate that A. anamensis was an important component of the Kanapoi early Pliocene ecosystems, and that its key adaptations allowed this species to thrive in complex and dynamic landscapes.

NEW RECORDS OF BIRDS IN THE SANTA CRUZ FORMATION (EARLY-MIDDLE MIOCENE) AT THE RÍO SANTA CRUZ VALLEY, PATAGONIA, ARGENTINA

The Santa Cruz Formation constitutes one of the most representative units of the Early-Middle Miocene of South America for its abundant and rich fossil record of vertebrates. The diversity of extinct birds is known so far by at least 17 species grouped in 15 genera and at least 10 families. Most of the avian taxa described from these levels come from localities of the Santa Cruz Province placed next to or along the Atlantic coast. New specimens recovered from the Río Santa Cruz valley, with accurate geographic and stratigraphic provenances, are presented in this contribution. They include rheids, tinamids, and phorusrhacids.

Variable preservation potential and richness in the fossil record of vertebrates

AbstractVariation in preservation and sampling probability clouds our estimates of past biodiversity. The most extreme examples are Lagerstätten faunas and floras. Although such deposits provide a wealth of information and represent true richness better than other deposits, they can create misleading diversity peaks because of their species richness. Here, we investigate how Lagerstätten formations add to time series of vertebrate richness in the UK, Germany and China. The first two nations are associated with well‐studied fossil records and the last is a country where palaeontology has a much shorter history; all three nations include noted Lagerstätten in their fossil records. Lagerstätten provide a larger proportion of China's sampled richness than in Germany or the UK, despite comprising a smaller proportion of its fossiliferous deposits. The proportions of taxa that are unique to Lagerstätten vary through time and between countries. Further, in all regions, we find little overlap between the taxa occurring in Lagerstätten and in ‘ordinary’ formations within the same time bin, indicating that Lagerstätten preserve unusual faunas. As expected, fragile taxa make up a greater proportion of richness in Lagerstätten than the remainder of the fossil record. Surprisingly, we find that Lagerstätten account for a minority of peaks in the palaeodiversity curves of all vertebrates (18% in the UK; 36% in Germany and China), and Lagerstätten count is generally not a good overall predictor of the palaeodiversity signal. Vastly different sampling probabilities through taxa, locations and time require serious consideration when analysing palaeodiversity curves.

New Crocodylomorph Material from the Fayum Depression, Egypt, Including the First Occurrence of a Sebecosuchian in African Late Eocene Deposits

ABSTRACT During the Cretaceous and Paleogene periods, the Earth experienced tectonic and climatic changes, which included continental drift following the breakup of the supercontinents Gondwana and Laurasia, the end-Cretaceous mass extinction event, and several climatic events, including the Paleocene–Eocene Thermal Maximum and the Middle Eocene Climatic Optimum. In response to increased temperatures and vacancies of ecospace left by the extinction of non-avian dinosaurs, mammal and reptile lineages that survived into the Eocene underwent immense evolutionary radiations that led to the diversification of crown clades, such as Crocodylia. Late Eocene deposits in northern Africa provide insights into how crocodyliforms responded to these tectonic and climatic events. Specifically, the Birket Qarun Formation in the Fayum Depression of Egypt contains several species of crown crocodylians as part of its rich fossil record of vertebrates. This study provides description of new material attributable to crocodylian taxa previously known from this formation, as well as newly recognized non-crocodylian mesoeucrocodylian material referable to Sebecosuchia. The sebecosuchian material provides important evidence attesting to the diversity of crocodyliforms in the late Eocene of Africa and expands the known biogeographic range of sebecosuchians.

Integumentary structure and composition in an exceptionally well-preserved hadrosaur (Dinosauria: Ornithischia).

Preserved labile tissues (e.g., skin, muscle) in the fossil record of terrestrial vertebrates are increasingly becoming recognized as an important source of biological and taphonomic information. Here, we combine a variety of synchrotron radiation techniques with scanning electron and optical microscopy to elucidate the structure of 72 million-year-old squamous (scaly) skin from a hadrosaurid dinosaur from the Late Cretaceous of Alberta, Canada. Scanning electron and optical microscopy independently reveal that the three-dimensionally preserved scales are associated with a band of carbon-rich layers up to a total thickness of ∼75 microns, which is topographically and morphologically congruent with the stratum corneum in modern reptiles. Compositionally, this band deviates from that of the surrounding sedimentary matrix; Fourier-transform infrared spectroscopy and soft X-ray spectromicroscopy analyses indicate that carbon appears predominantly as carbonyl in the skin. The regions corresponding to the integumentary layers are distinctively enriched in iron compared to the sedimentary matrix and appear with kaolinite-rich laminae. These hosting carbonyl-rich layers are apparently composed of subcircular bodies resembling preserved cell structures. Each of these structures is encapsulated by calcite/vaterite, with iron predominantly concentrated at its center. The presence of iron, calcite/vaterite and kaolinite may, independently or collectively, have played important roles in the preservation of the layered structures.

Ungulate turnover in the Koobi Fora Formation: Spatial and temporal variation in the Early Pleistocene

The Koobi Fora Formation, located east of Lake Turkana in northern Kenya, is well-known for its well-sampled vertebrate fossil record. Thousands of identifiable remains have been collected from three Early Pleistocene geologic members of the Koobi Fora Formation: the Upper Burgi (1.98–1.87 Ma), KBS (1.87–1.56 Ma), and Okote (1.56–1.38 Ma). The large sample from these members permits analysis of spatial and temporal variation in species composition, particularly as it relates to broader changes within the basin. To investigate paleoecological trends in the Koobi Fora Formation during this period, we examine spatial and temporal variation in the proportional abundance of a large sample (NISP = 3713) of ecologically diverse ungulate taxa, in addition to variation in enamel isotope δ13C values. We find that the Karari subregion experienced significant turnover within key large mammalian families (Bovidae, Suidae, and Equidae) during this period, while changes in other subregions (Ileret and Koobi Fora Ridge) were relatively minimal. Our analyses indicate drier conditions in the Karari during the regression of Paleolake Lorenyang as the dominant water-dependent taxa (e.g., the bovid tribe Reduncini and the suid genus Kolpochoerus) were largely replaced with taxa adapted to xeric habitats including the bovid tribe Alcelaphini and the suid genus Metridiochoerus. Little change was detected in proportional abundances of broad dietary groups (grazers: mixed-feeders: browsers). These findings provide a more resolved spatiotemporal resolution for the mammalian communities occupying the region during this time. They further highlight the importance of considering localized habitat differentiation in eastern Africa during the Early Pleistocene, acknowledging that fossil records document complex and dynamic systems which varied spatially and temporally on many scales, much like modern African ecosystems.

THE VALIDITY OF LAGOSUCHUS TALAMPAYENSIS ROMER, 1971 (ARCHOSAURIA, DINOSAURIFORMES), FROM THE LATE TRIASSIC OF ARGENTINA

The Chanares Formation (latest Middle–earliest Late Triassic) of northwestern Argentina is part of the Ischigualasto–Villa Union Basin and preserves a rich fossil vertebrate record discovered by a crew of the Museum of Comparative Zoology (Harvard University) led by Alfred Romer. A diverse non-dinosaurian dinosauromorph assemblage has been described from this formation and includes the iconic, small-sized “proto-dinosaur” Lagosuchus talampayensis Romer, 1971. This species has been crucial to understand the body plan of dinosaur precursors and the higher-level phylogenetic relationships of dinosaurs. More recently, authors considered this genus and species as nomina dubia. The aim of this contribution is to reassess the taxonomic validity of L. talampayensis. New observations indicate that the holotype of L. talampayensis differs from other avemetatarsalians, but not from the hypodigm of Marasuchus lilloensis, in the presence of a globose femoral head (strongly convex proximal and medial surfaces) with a distinctly dorsal orientation and a sub-oval outline in proximal view as a result of incipient posterior and posteromedial tuberosities. Thus, Lagosuchus talampayensis is here considered a senior synonym of “Marasuchus lilloensis” (Romer, 1972). Our conclusions have implications in the knowledge about early dinosauromorph diversity and the taxonomic richness of the group in the Chanares Formation.

The most representative vertebrate fossil record and palaeontological heritage from the western Pyrenees

The western Pyrenees is a territory with a remarkable geodiversity and an important fossil record, which constitutes a large archive of palaeobiodiversity. With respect to the vertebrate fossil record, the western Pyrenees (Basque-Cantabrian Region, Pamplona Basin and the north-western sector of the Ebro Basin) are relevant both from the point of view of palaeontological sites and fossil collections. Several vertebrate fossil sites are integrated into the Inventory of Geological Interest Sites (LIG) with high to very high palaeontological interest of the Autonomous Community of the Basque Country. The valuation of the palaeobiodiversity and fossil record is an important step for the study of palaeontological heritage of a territory and the set-up of geoconservation designations (e.g., LIG, geosites). However, the mere inclusion of the palaeontological assents in these geoconservation designations does not guarantee either their protection and conservation or the suitable management of the fossil collection The scientific and cultural dissemination of the palaeontological heritage of a territory like one studied here should have greater collaboration between the palaeontologists that have valued the palaeontological assets and the technicians and institutions that manage them. This requires the provision of specific budgetary items that enable the development of the different activities of research, conservation and social dissemination of this heritage.

Refined age and geological context of two of Australia’s most important Jurassic vertebrate taxa (Rhoetosaurus brownei and Siderops kehli), Queensland

Australia’s Jurassic vertebrate fossil record remains extremely sparse with only two dinosaur taxa and two temnospondyl amphibians identified to date. Of these, the spectacular and extremely well-preserved giant amphibian, Siderops kehli, and the only known pre-Cretaceous sauropod in Australia, Rhoetosaurus brownei, are perhaps the most important. The age of both specimens, and the stratigraphic context of Rhoetosaurus brownei, are weakly constrained and imprecisely defined, limiting our understanding of their evolutionary relationships within a broader Gondwanan context. To clarify and contextualise the evolutionary relationships and ages of these two iconic Jurassic taxa, we used UPb detrital zircon geochronology to date the sandstone matrix from around the bones of the historic museum specimens. The robust maximum depositional age for Siderops was calculated at 176.6 Ma ± 2 Ma, indicating that it is no older than late Toarcian, which refines existing biostratigraphic estimates. The Rhoetosaurus maximum depositional age was determined to be 162.6 ± 1.1 Ma, no older than early Oxfordian, demonstrating that the fossils are younger than expected, and definitely recovered from the Walloon Coal Measures.

A mixed vertebrate eggshell assemblage from the Transylvanian Late Cretaceous

A Late Cretaceous-aged multi-taxon nesting site from Romania preserved in three dimensions reveals the earliest example of nest site sharing yet known from the vertebrate fossil record. Eggshell and osteological evidence combined in this single accumulation demonstrate that at least four vertebrate taxa including enantiornithine birds and another avian of indeterminate affinities as well as crocodylomorphs and gekkotan squamates nested together in the same place. Colonial nesting in enantiornithines was previously described from this site; here, we present the first fossil evidence that other vertebrates also nested in the same place, perhaps exploiting the presence of the large bird colony. We describe four distinct eggshell morphotypes that have been collected from this site and draw palaeoecological inferences based on this unique multi-taxon nesting association.

The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific.

The extinct giant shark Otodus megalodon is the last member of the predatory megatoothed lineage and is reported from Neogene sediments from nearly all continents. The timing of the extinction of Otodus megalodon is thought to be Pliocene, although reports of Pleistocene teeth fuel speculation that Otodus megalodon may still be extant. The longevity of the Otodus lineage (Paleocene to Pliocene) and its conspicuous absence in the modern fauna begs the question: when and why did this giant shark become extinct? Addressing this question requires a densely sampled marine vertebrate fossil record in concert with a robust geochronologic framework. Many historically important basins with stacked Otodus-bearing Neogene marine vertebrate fossil assemblages lack well-sampled and well-dated lower and upper Pliocene strata (e.g., Atlantic Coastal Plain). The fossil record of California, USA, and Baja California, Mexico, provides such an ideal sequence of assemblages preserved within well-dated lithostratigraphic sequences. This study reviews all records of Otodus megalodon from post-Messinian marine strata from western North America and evaluates their reliability. All post-Zanclean Otodus megalodon occurrences from the eastern North Pacific exhibit clear evidence of reworking or lack reliable provenance; the youngest reliable records of Otodus megalodon are early Pliocene, suggesting an extinction at the early-late Pliocene boundary (∼3.6 Ma), corresponding with youngest occurrences of Otodus megalodon in Japan, the North Atlantic, and Mediterranean. This study also reevaluates a published dataset, thoroughly vetting each occurrence and justifying the geochronologic age of each, as well as excluding several dubious records. Reanalysis of the dataset using optimal linear estimation resulted in a median extinction date of 3.51 Ma, somewhat older than a previously proposed Pliocene-Pleistocene extinction date (2.6 Ma). Post-middle Miocene oceanographic changes and cooling sea surface temperature may have resulted in range fragmentation, while alongside competition with the newly evolved great white shark (Carcharodon carcharias) during the Pliocene may have led to the demise of the megatoothed shark. Alternatively, these findings may also suggest a globally asynchronous extinction of Otodus megalodon.

A new specimen of Platypterygius sachicarum (Reptilia, Ichthyosauria) from the Early Cretaceous of Colombia and its phylogenetic implications

ABSTRACTPlatypterygius sachicarum is one of the few Lower Cretaceous ichthyosaurian species described from the Hauterivian–Aptian-aged Paja Formation, the most complete Lower Cretaceous sedimentary sequence in northern South America. To date, P. sachicarum has been described only from a single skull, limiting morphological, stratigraphic, and phylogenetic comparisons. Here, we describe a new skull and associated postcranium of upper Barremian age from Villa de Leyva, Colombia, which represent the first documented postcranial remains of this species and enable detailed comparison with other Early Cretaceous ophthalmosaurid ichthyosaurs. Platypterygius sachicarum shares many morphological similarities with contemporaneous taxa from Europe but differs in both skull and tooth morphology from coeval South American species from northern South America and from the eastern Pacific. The additional data provide new diagnostic characters for this species and resolve the position of P. sachicarum as part of a polytomy of other species historically referred to Platypterygius. However, as with previous analyses, all recovered clades are poorly supported. The rich vertebrate fossil record of the Paja Formation provides an unparalleled opportunity to explore paleobiogeographic and paleoecological questions pertaining to Cretaceous marine reptiles; however, in most cases, a robust stratigraphic and phylogenetic framework remains elusive.

Sedimentary provenance and maximum depositional age analysis of the Cretaceous? Lapur and Muruanachok sandstones (Turkana Grits), Turkana Basin, Kenya

AbstractThe Turkana Basin of northwestern Kenya is well known for its rich Neogene–Quaternary vertebrate fossil record; however, it also represents one of the few locations in sub-Saharan Africa where Cretaceous vertebrate fossils, including dinosaurs and other archosaurs, are preserved. These Cretaceous deposits are colloquially referred to as the ‘Turkana Grits’, and assumed to be Cretaceous in age based on their limited biostratigraphy. The ‘Turkana Grits’ are overlain by Palaeogene volcanic rocks (<35 Ma), which are widely considered to record the earliest evidence of plume-related volcanism in the East African Rift System. In this study, we present the results of an integrated sedimentary provenance investigation of two units within the ‘Turkana Grits’ called the Lapur and Muruanachok sandstones. Analysis of U–Pb ages and Lu–Hf initial ɛHf(t) values from 1106 detrital zircons demonstrate that sediments are primarily derived from Neoarchaean and Neoproterozoic basement sources, except for six Palaeogene grains from the upper Lapur Sandstone, which are of unknown provenance. Considered together, these data point to the Mozambique Belt, which makes up the nearby rift flanks, as the primary provenance source. This is consistent with palaeocurrent data, and suggests localized sediment input by alluvial fans, which fed into NNW-directed fluvial systems. Perhaps the most surprising finding is the identification of the late Paleocene detrital zircons, which not only demonstrate that the depositional age for the top of the formation is Paleocene rather than Cretaceous, but also provides possible evidence for the oldest Palaeogene volcanic activity within the East African Rift System.

A new species of the deep-bodied actinopterygian Dapedium from the Middle Jurassic (Aalenian) of southwestern Germany.

Dapedium is one of the most abundant and diverse genera of ganoid fishes from the Early Jurassic fossil lagerstätte of Europe. In spite of its abundance, however, its timing of extinction is poorly constrained, with the youngest described material being Early Jurassic in age. We describe new diagnostic and relatively complete material of a large species of Dapedium (standard length estimated at 50 cm) from the Middle Jurassic (earliest Aalenian) Opalinuston Formation of Baden-Württemberg, Germany. The Aalenian material represents a distinct species, D. ballei sp. nov., differing from Early Jurassic species in a unique combination of characters pertaining to the shape of the dermal skull elements, pectoral fin position, and scale shape and ornamentation. However, although D. ballei sp. nov. exhibits a unique combination of characters, there are no autapomorphies with which to distinguish it from the Toarcian species of Dapedium. Dapedium ballei represents the geologically youngest species of Dapedium, extending the range of this genus into the Middle Jurassic. The Opalinuston Formation fills an important gap in the marine vertebrate fossil record, and finds from this horizon have the potential to greatly improve our understanding of evolutionary dynamics over this period of faunal transition.

Lower Miocene alligatoroids (Crocodylia) from the Castillo Formation, northwest of Venezuela

Crocodyliform diversity was particularly high during the middle and late Miocene of South America, with up to 12 species recovered from a single geological unit. Nonetheless, the early Miocene fossil record of low-latitude vertebrates is scarce; hence, crocodylians remain poorly known in the region. The Castillo Formation, located in the northwest of Venezuela, preserves an interesting vertebrate fauna with a well-constrained late early Miocene age. Previous work dealing with crocodylians of this formation only recorded three taxa: the gavialoid Siquisiquesuchus venezuelensis and Gryposuchus sp. and indeterminate alligatoroid remains. New cranial and mandibular material recently recovered from the Castillo Formation allows us to document four previously unrecognised alligatoroid forms: Purussaurus sp., Caiman sp., an indeterminate caimanine and an indeterminate alligatoroid. With six taxa, the crocodylian assemblage reveals a previously undocumented relatively high taxonomic diversity in the early Miocene. The Castillo crocodylians show a broad range of morphological disparity and body sizes ranging from small (2.5 m–62 kg) to large (7.5 m–1600 kg) taxa. Thus, crocodylian niche partition, as well as the abundance and variety of resources and environmental heterogeneity of aquatic ecosystems in South America, were already established by at least the early Miocene. The presence of Caiman in ~ 18 Ma strata represents the unequivocally earliest record of the taxon in South America and allows us to propose that the origin of the jacareans is more likely to have occurred during or before the early Miocene, challenging previous molecular hypotheses.

A primitive actinopterygian braincase from the Tournaisian of Nova Scotia.

The vertebrate fossil record of the earliest Carboniferous is notoriously poorly sampled, obscuring a critical interval in vertebrate evolution and diversity. Recent studies of diversity across the Devonian–Carboniferous boundary have proposed a vertebrate mass extinction at the end-Devonian, and recent phylogenies suggest that the origin of the actinopterygian crown may have occurred in the earliest Carboniferous, as part of a broader recovery fauna. However, the data necessary to test this are limited. Here, we describe a partial actinopterygian skull, including diagnostic elements of the posterior braincase, from the Tournaisian Horton Bluff Formation of Blue Beach, Nova Scotia. The braincase surprisingly shows a confluence of characters common in Devonian taxa but absent in Mississippian forms, such as an open spiracular groove; lateral dorsal aortae that pass through open broadly separated, parallel grooves in the ventral otoccipital region, posterior to the articulation of the first infrapharyngobranchial and an intertemporal–supratemporal complex. Phylogenetic analysis places it deep within the actinopterygian stem, among Devonian moythomasiids and mimiids, suggesting more phylogenetically inclusive survivorship of stem group actinopterygians across the end-Devonian mass extinction. With a high lineage survivorship in tetrapods and lungfish across the Devonian–Carboniferous boundary and high vertebrate diversity at Tournaisian localities, this hints at a more gradual turnover between Devonian and Carboniferous vertebrate faunas.

Carnivore stable carbon isotope niches reflect predator-prey size relationships in African savannas.

Predator-prey size relationships are among the most important patterns underlying the structure and function of ecological communities. Indeed, these relationships have already been shown to be important for understanding patterns of macroevolution and differential extinction in the terrestrial vertebrate fossil record. Stable isotope analysis (SIA) is a powerful remote approach to examining animal diets and paleodiets. The approach is based on the principle that isotope compositions of consumer tissues reflect those of their prey. In systems where resource isotope compositions are distributed along a body size gradient, SIA could be used to reconstruct predator-prey size relationships. We analyzed stable carbon isotope distributions amongst mammalian herbivores in extant and Plio-Pleistocene African savanna assemblages, and show that the range of δ13 C values among mammalian prey species (herbivores and rodents) increases with body mass (BM), because C4 plant feeding (essentially grazing) is more common among larger taxa. Consequently, δ13 C values of mammalian carnivores in these systems are related to species' BM, reflecting a higher average C4 prey component in the diets of larger-bodied carnivores. This pattern likely emerges because only the largest carnivores in these systems have regular access to the C4 prey base, whereas smaller carnivores do not. The δ13 C-BM relationship observed in mammalian carnivores is a potentially powerful approach for reconstructing and parameterizing predator-prey size relationships in contemporary and fossil savanna assemblages, and for interpreting how various behavioral, ecological and environmental factors influence prey size selection.

New dinosaur remains from the Quiricó Formation, Sanfranciscana Basin (Lower Cretaceous), Southwestern Brazil

The vertebrate fossil record from the Quiricó Formation, Sanfranciscana Basin (Lower Cretaceous), is scarce, but the remains yet found are of great importance for the understanding of the paleobiogeographic and biogeographic processes that took place during the initial stages that led to the opening of the Atlantic Ocean. In this work, new occurrences of sauropod dinosaur bones and theropod teeth from the Barremian–Aptian Quiricó Formation, collected in Campo Azul and Olhos D'Água, State of Minas Gerais, Brazil, are described. The fossils comprise isolated bones of sauropod dinosaurs, such as fragments of sauropod vertebrae, and isolated theropod teeth, both preserved in lacustrine siltstones and associated sandstones. The anatomical features of the sauropod bones suggest that they can be assigned to Rebbachisauridae and the morphological analysis of the isolated theropod teeth placed them within Abelisauridae and Carcharodontosauridae. This suggests that during the Early Cretaceous, the dinosaurian fauna from the southeastern Brazil was more closely related to African faunas than to other South-American ones.

On a cranial bony nodular protuberance on Mourasuchus pattersoni Cidade et al. 2017 (Crocodylia, Alligatoroidea) from the late Miocene of Venezuela

Mourasuchus pattersoni, from the late Miocene Urumaco Formation of Venezuela, is the fourth and most recent species described for the genus. The holotype, and only known specimen, is comprised of an almost complete skull with both mandibular rami and several postcranial remains. In ventral view, the right palatine bone has a spherical, nodular bony protuberance located on the anterior portion, near the suture with the maxilla. Unfortunately, we cannot assign a specific diagnosis based only on macroscopic inspection. Its appearance, form and location are compatible with three conditions: torus palatinus, a common benign intraoral bone overgrowth; osteoma, a benign neoplasical overgrowth of the bone; and hamartoma, an overgrowth of normal bone tissue that can only be differed from an osteoma by histological features. While occurrences of torus palatinus or hamartomas are not yet known in the nonhominid vertebrate fossil record, there are previous records of osteomas in fossil vertebrates, including in crocodylians, such as a specimen assigned to ‘Crocodylus sp.’ from the Eocene, aside from several records for living crocodylians. Future studies are needed to uncover an accurate diagnosis of this unusual structure and help increase our knowledge of paleopathology in fossil crocodylomorphs in general, especially in the Caimaninae clade.

A probable ankylosaurian (Dinosauria, Thyreophora) from the Early Cretaceous of New South Wales, Australia

Bell, P.R., Burns, M.E. & Smith, E.T. October 2017. A probable ankylosaurian (Dinosauria, Thyreophora) from the Early Cretaceous of New South Wales, Australia. Alcheringa 42, 120–124. ISSN 0311-5518.We describe an isolated osteoderm from the Albian Griman Creek Formation where it is exposed near the town of Lightning Ridge in central-northern New South Wales, Australia. Several lines of evidence allow referral of this element to the Ankylosauria—a group that epitomises body armour and ubiquitous osteodermal coverage among dinosaurs. Despite the abundant record of fossil vertebrates from this interval, ankylosaurians have not been previously reported, although, they have been described from penecontemporaneous deposits in western Queensland and Victoria. This discovery, therefore, provides an important link between the northerly faunas (including the Griman Creek Formation) that flourished at the edge of the epeiric Eromanga Sea, with those from the sub-polar rift-valley system of Victoria during the mid-Cretaceous.Phil R. Bell [pbell23@une.edu.au], School of Environmental and Rural Science, University of New England, Armidale 2351, NSW, Australia; Michael E. Burns [mburns3@jsu.edu], Department of Biology, Jacksonville State University, 700 Pelham Rd N., Jacksonville, AL 36265-2138, USA; Elizabeth T. Smith [elizabethtsmith@exemail.com.au], Australian Opal Centre, Lightning Ridge 2834, NSW, Australia.