During the latest Cretaceous, western North America experienced several regressive and transgressive cycles of the Western Interior Seaway (WIS). Closely related, time-successive taxa of tyrannosaurids, ceratopsids, hadrosaurids, and pachycephalosaurids have been proposed to have evolved via anagenesis driven by habitat area fluctuations related to sea level change. Previous examinations into these anagenetic hypotheses have resulted in equivocal results. However, evolution related to this WIS hypothesis has yet to be tested for Pachycephalosauria. Originally, it was hypothesized that an undescribed taxon from the Two Medicine Formation constituted an anagenetic intermediate between the Campanian Stegoceras validum and the Maastrichtian Pachycephalosaurus wyomingensis. Here we describe this Two Medicine Formation pachycephalosaurid and test the proposed anagenetic lineage. This taxon is the first pachycephalosaurid from the Two Medicine Formation, and the massive frontoparietal dome indicates that it was the third largest North American pachycephalosaurid. Phylogenetic analyses recover this new taxon distant from both Stegoceras and Pachycephalosaurus; thus, refuting the hypothesis that this taxon constitutes any part of an ancestor-descent series between Stegoceras and Pachycephalosaurus. However, the new taxon not only increases understanding of pachycephalosaurid morphology and diversity, but shows that this clade contained relatively large body-sized taxa as early as the Middle Campanian.

A partial skull of a pachycephalosaurid from the Upper Cretaceous Hell Creek Formation, Montana, is interpreted as a new taxon, Platytholus clemensi gen. et sp. nov. MOR 2915 does not fit into an ontogenetic continuum of known pachycephalosaurids from the Hell Creek Formation, Montana, and contemporaneous sediments from the Western Interior. Comparisons to known ontogimorphs of Sphaerotholus and Pachycephalosaurus preclude including this specimen into an ontogenetic series of either taxon. We hypothesize that MOR 2915 is a new species based on a relatively low, broad dome at this advanced ontogenetic age that is neither round nor oval in dorsal view, distinct but fused lateral cranial elements fully incorporated into the dome without any dorsal lobe differentiation, and individual tab-like tubercle ornamentation dorsolaterally. Phylogenetic analysis posits that Platytholus clemensi is a Prenocephale-grade taxon deeply nested within Pachycephalosaurinae, but it is not a member of Pachycephalosaurini. Platytholus clemensi is intermediate in size between the other contemporaneous pachycephalosaurids in the Hell Creek Formation and suggests a diverse set of taxa-partitioned ecological niches by body size. We confirm a well organized, major internal vascular network using high resolution computed tomography. Foramina present on the orbital roofs indicate these canals penetrated the entire ceiling of the orbits within the frontal and supraorbital bones. Abundant neurovascular canals passing through the dome to the ectocranial surface indicate a keratinous structure of some kind, possibly with a vertical structural framework, was present on the dome. We review the history of the head-butting hypothesis and associated behavioral implications.

The thickened frontoparietal in pachycephalosaurid dinosaurs expands dramatically during ontogeny from a flat-headed to a domed state. This expansion results in the formation of zonal tissue characterized largely by differences in vascularity and bony tissue structure that changes through ontogeny. Void space identified in CT scans of the frontoparietal is a suitable proxy for relative vascularity. An increase in relative vascularity occurs with the development of the dome in the pachycephalosaur Stegoceras validum, followed by a significant decrease in late stage ontogeny. We employ a script adapted from an algorithm for human cortical bone imaging to: (1) determine the percent vascularity in any given CT slice; (2) quantify these observed changes in relative vascularity within a complete frontoparietal; and (3) identify ontogenetic changes in vascularity from a cranial growth series of Stegoceras. Morphological landmarks identified in the CT scans facilitate an accurate slice-by-slice comparison of homologous regions of the dome between skulls. This new tool enables: (1) a complete assessment of bone vascularity from CT scans; (2) is applicable to any fossil or modern bone in the vertebrate skeleton; and (3) provides an alternative measure to pixel-by-pixel manual thresholding, a time intensive and subjective process.

The radiation of archosauromorph reptiles in the Triassic Period produced an unprecedented collection of diverse and disparate forms with a mix of varied ecologies and body sizes. Some of these forms were completely unique to the Triassic, whereas others were converged on by later members of Archosauromorpha. One of the most striking examples of this is with Triopticus primus, the early dome-headed form later mimicked by pachycephalosaurid dinosaurs. Here we fully describe the cranial anatomy of Triopticus primus, but also recognize a second dome-headed form from a Upper Triassic deposit in present-day India. The new taxon, Kranosaura kuttyi gen. et sp. nov., is likely the sister taxon of Triopticus primus based on the presence of a greatly expanded skull roof with a deep dorsal opening (possibly the pineal opening) through the dome, similar cranial sculpturing, and a skull table that is expanded more posterior than the posterior extent of the basioccipital. However, the dome of Kranosaura kuttyi gen. et sp. nov. extends anterodorsally, unlike that of any other archosauromorph. Histological sections and computed tomographic reconstructions through the skull of Kranosaura kuttyi gen. et sp. nov. further reveal the uniqueness of the dome of these early archosauromorphs. Moreover, our integrated analysis further demonstrates that there are many ways to create a dome in Amniota. The presence of 'dome-headed' archosauromorphs at two localities on the western and eastern portions of Pangea suggests that these archosauromorphs were widespread and are likely part of more assemblages than currently recognized.

The ontogeny and taxonomy of the dome-headed pachycephalosaurs are topics of continued debate. Pachycephalosaurid diversity in the Maastrichtian of North America is particularly controversial, and the validity and composition within the genus Sphaerotholus remains unresolved. While the type species, S. goodwini, is generally considered valid, debate has centred around the validity and taxonomy of S. buchholtzae and S. edmontonensis. Here we employ morphometrics, histology and phylogenetic analysis to resolve these issues. An ontogenetic assessment of S. buchholtzae (N > 20) confirms previously observed ontogenetic morphologies: inflation of the frontoparietal dome, obliteration of tesserate surface texture, blunting of the peripheral nodes and decreasing void space within the dome. While linear bivariate analysis finds S. edmontonensis nested within S. buchholtzae, three-dimensional geometric morphometrics supports S. edmontonensis and S. buchholtzae as distinct species. Phylogenetic analysis recovers a Sphaerotholus lineage with S. goodwini as sister-taxon to a clade formed by S. edmontonensis and S. buchholtzae. The stratigraphic, phylogenetic, morphometric and ontogenetic data support the validity of both S. edmontonensis and S. buchholtzae, and their placement within the genus Sphaerotholus. The morphological similarities of S. edmontonensis to immature S. buchholtzae, and the slightly older geological age of S. edmontonensis, suggest that S. edmontonensis and S. buchholtzae may be part of an anagenetic lineage.

Societal Impact Statement Enset is a staple food for over 20 million people via its starch‐rich corm and pseudostem, yet it is virtually unknown outside a narrow zone of cultivation in southern Ethiopia. Due to acculturation and urbanization coupled with climate change, emerging pests and the introduction of new crops, the extensive indigenous knowledge associated with this crop is in danger of being lost, imperilling the future food security and prosperity of millions of Ethiopians. Here, we synthesize the current state of enset ethnobotanical research, identifying key gaps and challenges, and provide a framework for further enset research to safeguard this important, but neglected, tropical crop. Summary Enset (Ensete ventricosum (Welw.) Cheesman) is the major starch staple of the Ethiopian Highlands, where its unique attributes enhance the food security of approximately 20 million people and have earned it the title “The Tree Against Hunger”. Yet enset‐based agriculture is virtually unknown outside of its narrow zone of cultivation, despite growing wild across much of East and Southern Africa. Here, we review historical production data to show that the area of land under enset production in Ethiopia has reportedly increased 46% in two decades, whilst yield increased 12‐fold over the same period, making enset the second most produced crop species in Ethiopia—though we critically evaluate potential issues with these data. Furthermore, we address a major challenge in the development and wider cultivation of enset, by reviewing and synthesizing the complex and fragmented agronomic and ethnobotanic knowledge associated with this species; including farming systems, processing methods, products, medicinal uses and cultural importance. Finally, we provide a framework to improve the quality, consistency and comparability of data collected across culturally diverse enset‐based agricultural systems to enhanced sustainable use of this neglected starch staple. In conclusion, we discuss the challenges and opportunities for enset cultivation beyond its restricted distribution, and the regional food security potential it could afford smallholders elsewhere in Southern and East Africa.

In the Cretaceous of North America, environmental sensitivity and habitat specialization have been hypothesized to explain the surprisingly restricted geographic ranges of many large-bodied dinosaurs. Understanding the drivers behind this are key to determining broader trends of dinosaur species and community response to climate change under greenhouse conditions. However, previous studies of this question have commonly examined only small components of the paleo-ecosystem or operated without comparison to similar modern systems from which to constrain interpretations. Here we perform a high-resolution multi-taxic δ13C and δ18O study of a Cretaceous coastal floodplain ecosystem, focusing on species interactions and paleotemperature estimation, and compare with similar data from extant systems. Bioapatite δ13C preserves predator-prey offsets between tyrannosaurs and ornithischians (large herbivorous dinosaurs), and between aquatic reptiles and fish. Large ornithischians had broadly overlapping stable isotope ranges, contrary to hypothesized niche partitioning driven by specialization on coastal or inland subhabitat use. Comparisons to a modern analogue coastal floodplain show similar patterns of ecological guild structure and aquatic-terrestrial resource interchange. Multi-taxic oxygen isotope temperature estimations yield results for the Campanian of Alberta (Canada) consistent with the few other paleotemperature proxies available, and are validated when applied for extant species from a modern coastal floodplain, suggesting that this approach is a simple and effective avenue for paleoenvironmental reconstruction. Together, these new data suggest that dinosaur niche partitioning was more complex than previously hypothesized, and provide a framework for future research on dinosaur-dominated Mesozoic floodplain communities.

BACKGROUNDEnset (Ensete ventricosum, Musaceae) is an African crop that currently provides the staple food for approx. 20 million Ethiopians. Whilst wild enset grows over much of East and Southern Africa and the genus extends across Asia to China, it has only ever been domesticated in the Ethiopian Highlands. Here, smallholder farmers cultivate hundreds of landraces across diverse climatic and agroecological systems.SCOPEEnset has several important food security traits. It grows over a relatively wide range of conditions, is somewhat drought-tolerant, and can be harvested at any time of the year, over several years. It provides an important dietary starch source, as well as fibres, medicines, animal fodder, roofing and packaging. It stabilizes soils and microclimates and has significant cultural importance. In contrast to the other cultivated species in the family Musaceae (banana), enset has received relatively little research attention. Here, we review and critically evaluate existing research, outline available genomic and germplasm resources, aspects of pathology, and explore avenues for crop development.CONCLUSIONEnset is an underexploited starch crop with significant potential in Ethiopia and beyond. Research is lacking in several key areas: empirical studies on the efficacy of current agronomic practices, the genetic diversity of landraces, approaches to systematic breeding, characterization of existing and emerging diseases, adaptability to new ranges and land-use change, the projected impact of climate change, conservation of crop wild relatives, by-products or co-products or non-starch uses, and the enset microbiome. We also highlight the limited availability of enset germplasm in living collections and seedbanks, and the lack of knowledge of reproductive and germination biology needed to underpin future breeding. By reviewing the current state of the art in enset research and identifying gaps and opportunities, we hope to catalyse the development and sustainable exploitation of this neglected starch crop.

Stable isotopes are powerful tools for elucidating ecological trends in extant vertebrate communities, though their application to Mesozoic ecosystems is complicated by a lack of extant isotope data from comparable environments/ecosystems (e.g. coastal floodplain forest environments, lacking significant C-4 plant components). We sampled 20 taxa across a broad phylogenetic, body size, and physiological scope from the Atchafalaya River Basin of Louisiana as an environmental analogue to the Late Cretaceous coastal floodplains of North America. Samples were analysed for stable carbon, oxygen and nitrogen isotope compositions from bioapatite and keratin tissues to test the degree of ecological resolution that can be determined in a system with similar environmental conditions, and using similar constraints, as those in many Mesozoic assemblages. Isotopic results suggest a broad overlap in resource use among taxa and considerable terrestrial-aquatic interchange, highlighting the challenges of ecological interpretation in C-3 systems, particularly when lacking observational data for comparison. We also propose a modified oxygen isotope-temperature equation that uses mean endotherm and mean ectotherm isotope data to more precisely predict temperature when compared with measured Atchafalaya River water data. These results provide a critical isotopic baseline for coastal floodplain forests, and act as a framework for future studies of Mesozoic palaeoecology.

Uncorrected/ungrouped stable isotope data

The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic.

Despite over a century of intense collecting, the Hell Creek Formation has produced exceedingly few specimens of small juveniles and nestling-sized dinosaurs. Here, we report on the first cranial material of nestling-sized hadrosaurid dinosaurs from the formation. The specimens were recovered from the Sandstone Basin locality in Garfield County, northeastern Montana. The material consists of two dentaries, a surangular, and a quadrate from disassociated individuals, which through ontogenetically independent characters allows assignment of the surangular (UCMP 235857) and quadrate (UCMP 235859) to Hadrosaurinae and the dentary (UCMP 235860) to Edmontosaurus. Since Edmontosaurus annectens is the only known hadrosaurid in the formation, we hypothesize that these specimens represent the earliest ontogenetic growth stage of E. annectens providing a significant ontogenetic extension when assessing aspects of cranial ontogeny in this taxon. Using the newly identified nestling cranial material as end members of ontogenetic series for each element in E. annectens, we evaluated ontogenetic variability in phylogenetic characters associated with these elements that are used in assessing phylogenetic relationships among hadrosaurids. Although the quadrate and surangular generally develop isometrically and show minimal ontogenetic variation in morphology, the dentary undergoes significant ontogenetic changes. In particular, the dental battery exhibits a high degree of intraspecific variability through ontogeny. Ontogenetic variability in the dentary should reflect a commensurate degree of variation in the jaws and facial skeleton, suggesting caution should be used when taxonomically identifying small edmontosaur material, such as that known from Alaska. Taxonomic identification of new taxa should be restricted to adult individuals until enough specimens are available to adequately assess taxonomic variation in ontogenetically equivalent semaphorants/ontogimorphs for a large range of complementing taxa.

Ethiopia preserves extensive Mesozoic non-marine sedimentary sequences, but dinosaur fossils are exceptionally rare. The record is limited to a handful of theropod and ornithischian teeth from the Upper Jurassic Mugher Mudstone of the eastern margin of the Northwest Plateau, which has otherwise produced a diverse vertebrate fossil assemblage including actinopterygians, dipnoans, testudineans, crocodyliforms, and mammaliaforms. Here, we report the discovery of the first confirmed sauropod dinosaur from Ethiopia. The tooth BST VP-1/1 comes from a fine-to medium-grained, pebble and clast-rich zone with concentrated lenses of vertebrate microfossils in the lower part of the Mugher Mudstone. BST VP-1/1 is broad crowned, complete to the root, and slightly ellipsoidal midway in cross-section proximally toward the root. The distal half of the tooth has a chisel-like appearance. BST VP-1/1 is planar lingually, convex labially, and narrows apically. These features compare closely with those of early macronarians, such as Giraffatitan brancai from the penecontemporaneous Tendaguru Formation in Tanzania. This specimen demonstrates the presence of sauropods in Ethiopia for the first time, and indicates that macronarians were widespread in East Africa during the Late Jurassic Epoch.

Natural history data for taxa sampled in this study

The current status of enset in cultivation in Ethiopia and its more widely distributed wild populations is reviewed. Biodiversity research gaps are identified, and the potential benefits of the plant and benefits of undertaking that research are discussed, in particular on food and resource security and livelihoods in Ethiopia. Knowledge of the resilience of enset will provide the evidence base underpinning a decision whether to expand its use in Africa.Keywords/phrases: Diversity, Enset, Food security, Livelihoods, Resilience

The Hell Creek Formation preserves one of the most intensely studied late Cretaceous terrestrial fossil units. Over 22 dinosaur genera are currently recognized from this unit, but the record of juvenile individuals is surprisingly limited. Here, we document a nestling hadrosaur that represents the first occurrence of an articulated nestling dinosaur skeleton from the latest Cretaceous (late Maastrichtian) of North America. The specimen (UCMP 128181) preserves a partial scapula, nearly complete rib cage, vertebral series from the shoulder to mid-tail, a large portion of the pelvic girdle, and both hind limbs through a combination of bone and/or natural impressions in the concretion. It is assignable to the genus Edmontosaurus based on the shape of the prepubic process, or blade, of the pubis. The specimen represents the earliest ontogenetic growth stage of Edmontosaurus cf. annectens and possesses a femur length of 148 mm. It greatly contributes as a new end member to a sample of associated Edmontosaurus skeletons that is well suited for allometrically testing the hypothesized ontogenetic gait shift in hadrosaurs from bipedal juveniles to quadrupedal adults using individual limb proportions. Although UCMP 128181 does not preserve forelimbs, regressions based on associated Edmontosaurus skeletons (N = 25) reveal overall isometry of the forelimb relative to the hind limb, and within each limb. These data indicate that Edmontosaurus nestlings were anatomically capable of fully quadrupedal locomotion and provide no compelling evidence to support an ontogenetic gait shift in hadrosaurids.

New end-stage juvenile specimens of Pachycephalosaurus from the Upper Cretaceous Hell Creek Formation, Montana, confirm the earliest expression of squamosal nodes, parietal ornamentation, and jugal morphology in the smallest and presumably youngest individuals yet known. High-resolution computed tomography of the slightly thickened, undomed parietal reveals a dense cortex, a highly cancellous interior of irregularly shaped erosion cavities, and bony trabeculae indicative of primary, fast growing bone. The parietal, with its highly ornamented septum morphology and patent sutures, is nearly identical to the holotype of Dracorex hogwartsia,' and combined with these new internal histological details, supports the alternative interpretation that D. hogwartsia' is a juvenile Pachycephalosaurus wyomingensis. The squamosal nodes grow into an array of horns and secondary nodes exemplified by the pachycephalosaurin Stygimoloch spinifer' considered in this study to be a subadult P. wyomingensis. Unlike the squamosal ornamentation, the hypertrophied midline row of parietal nodes is transient as the frontoparietal dome expands later in ontogeny. We propose the term ontogimorph' as a substitute for semaphoront' to describe these taxon-specific morphological variants that grow allometrically and express extreme cranial morphology along a postnatal growth continuum ontogenetically. These juvenile-, sub-adult-, and adult-specific features in the skull of Pachycephalosaurus may have allowed the visual identification of ontogimorphs and signal their changing sociobiological status.Citation for this article: Goodwin, M. B., and D. C. Evans. 2016. The early expression of squamosal horns and parietal ornamentation confirmed by new end-stage juvenile Pachycephalosaurus fossils from the Upper Cretaceous Hell Creek Formation, Montana. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1078343.

The persistence of original soft tissues in Mesozoic fossil bone is not explained by current chemical degradation models. We identified iron particles (goethite-αFeO(OH)) associated with soft tissues recovered from two Mesozoic dinosaurs, using transmission electron microscopy, electron energy loss spectroscopy, micro-X-ray diffraction and Fe micro-X-ray absorption near-edge structure. Iron chelators increased fossil tissue immunoreactivity to multiple antibodies dramatically, suggesting a role for iron in both preserving and masking proteins in fossil tissues. Haemoglobin (HB) increased tissue stability more than 200-fold, from approximately 3 days to more than two years at room temperature (25°C) in an ostrich blood vessel model developed to test post-mortem 'tissue fixation' by cross-linking or peroxidation. HB-induced solution hypoxia coupled with iron chelation enhances preservation as follows: HB + O2 > HB - O2 > -O2 >> +O2. The well-known O2/haeme interactions in the chemistry of life, such as respiration and bioenergetics, are complemented by O2/haeme interactions in the preservation of fossil soft tissues.

Recent descriptions of blood vessels recovered from dinosaur bones have raised many questions regarding tissue diagenesis and the associated chemical pathways that led to preservation. Previous analyses have identified preserved elastin and collagen proteins in a variety of specimens [1][2]. In particular, the mechanical, chemical, and thermal susceptibility of fibrillar collagen is partially dependent on the degree of intermolecular crosslinking. While collagen crosslinking can be either enzymatically or non-enzymatically driven in life, in death, only non-enzymatic pathways are available. Hence, non-enzymatic intermolecular crosslinking of fibrillar collagen supermolecular networks in fossil blood vessels has been suggested as a possible contributor to tissue longevity.