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Despite the recognition that bone histology provides much information about the life history and biology of extinct animals, osteohistology of extinct marsupials is sorely lacking. We studied the bone histology of the ca. 15-million-year-old Nimbadon lavarackorum from Australia to obtain insight into its biology. The histology of thin sections of five femora and five tibiae of juveniles, subadult, and adult Nimbadon lavarackorum was studied. Growth marks in the bones suggest that N. lavarackorum took at least 7–8 years (and likely longer) to reach skeletal maturity. The predominant bone tissue during early ontogeny is parallel-fibered bone, whereas an even slower rate of bone formation is indicated by the presence of lamellar bone tissue in the periosteal parts of the compacta in older individuals. Deposition of bone was interrupted periodically by lines of arrested growth or annuli. This cyclical growth strategy indicates that growth in N. lavarackorum was affected by the prevailing environmental conditions and available resources, as well as seasonal physiological factors such as decreasing body temperatures and metabolic rates.

The extinction of large-bodied terrestrial ‘megafauna’ during earlier phases of the Quaternary had a significant impact on the transforming structure of ecosystems. However, the causes of such losses remains difficult to determine in part because of a paucity of reliable geochronological information about the taxa involved. This is especially true for continents such as Australia where the majority of extinct species have never been dated using radiometric and/or luminescence methods. Here we add new understanding about the geochronology of the world's largest-ever marsupial, the giant wombat-like Diprotodon optatum, an iconic member of the large herbivore guild of Pleistocene Australia. We present 28 new direct U-series ages (dentine) and 10 luminescence ages (sediments) for D. optatum fossils from three sites in tropical north and subtropical eastern Australia. The luminescence ages lie close to saturation for the tropical northern site of Floraville and therefore indicate minimum ages, and sediments from Gowrie Creek in the Darling Downs were mixed and can only be stated as a likely age range. Nevertheless the results assist in our broader understanding of the timing of persistence of the species. Our results demonstrate that the species roamed the northern tropics at least until the mid-Pleistocene (ca. 420 ka). They likely remained widespread during Marine Isotope Stage 5 (ca. 110 ka) and were abundant on the Darling Downs of eastern Australia. The youngest of the new ages that we report (ca. 60 ka) are from Neds Gully on the Darling Downs, a catchment previously considered by some to contain among the last survivors of the now-extinct megafauna. The new dated record demonstrates that deposits of varying ages occur within the catchment. Consequently, existing species lists that treat Neds Gully as a single faunal assemblage are likely significantly time-averaged and overinflated in terms of palaeo-diversity.

With 14 species recorded, the Miocene La Venta bat fauna is the most diverse bat paleocommunity in South America. It includes the oldest plant-visiting bat in the New World and some of the earliest representatives of the extant families Phyllostomidae, Thyropteridae, and Noctilionidae. La Venta'sNotonycteris magdalenensisis an extinct member of the subfamily Phyllostominae, a group of modern Neotropical animalivorous bats, and is commonly included in studies of the evolution of Neotropical bats, but aspects of its biology remain unclear. In this study, we used multivariate dental topography analysis (DTA) to reconstruct the diet ofN. magdalenensisby quantitatively comparing measures of molar complexity with those of 25 modern noctilionoid species representing all major dietary habits in bats. We found clear differences in molar complexity between dietary guilds, indicating that DTA is potentially an informative tool to study bat ecomorphology. Our results suggestN. magdalenensiswas probably an omnivore or insectivore, rather than a carnivore like its modern relativesChrotopterus auritusandVampyrum spectrum. Also, we reconstructed the body mass ofN. magdalenensisto be ~95 g, larger than most insectivorous bats, but smaller than the largest carnivorous bat (V. spectrum). Our results confirm thatN. magdalenensiswas not a specialized carnivore. It remains to be demonstrated that the specialized carnivory ecological niche was occupied by the same lineage of phyllostomines from at least the middle Miocene. Combining our diet and body-mass reconstructions, we suggest thatN. magdalenensisexhibits morphological pre-adaptations crucial for the evolution of specialized carnivory.

Little is known about how the large brains of mammals are accommodated into the dazzling diversity of their skulls. It has been suggested that brain shape is influenced by relative brain size, that it evolves or develops according to extrinsic or intrinsic mechanical constraints, and that its shape can provide insights into its proportions and function. Here, we characterise the shape variation among 84 marsupial cranial endocasts of 57 species including fossils, using 3D geometric morphometrics and virtual dissections. Statistical shape analysis revealed four main patterns: over half of endocast shape variation ranges between elongate and straight to globular and inclined; little allometric variation with respect to centroid size, and none for relative volume; no association between locomotion and endocast shape; limited association between endocast shape and previously published histological cortex volumes. Fossil species tend to have smaller cerebral hemispheres. We find divergent endocast shapes in closely related species and within species, and diverse morphologies superimposed over the main variation. An evolutionarily and individually malleable brain with a fundamental tendency to arrange into a spectrum of elongate-to-globular shapes – possibly mostly independent of brain function - may explain the accommodation of brains within the enormous diversity of mammalian skull form.

Bats show a remarkable ecological diversity that is reflected both in dietary and foraging guilds (FGs). Cranial ecomorphological adaptations linked to diet have been widely studied in bats, using a variety of anatomical, computational and mathematical approaches. However, foraging-related ecomorphological adaptations and the concordance between cranial and postcranial morphological adaptations remain unexamined in bats and limited to the interpretation of traditional aerodynamic properties of the wing (e.g. wing loading [WL] and aspect ratio [AR]). For this reason, the postcranial ecomorphological diversity in bats and its drivers remain understudied. Using 3D virtual modelling and geometric morphometrics (GMM), we explored the phylogenetic, ecological and biological drivers of humeral morphology in bats, evaluating the presence and magnitude of modularity and integration. To explore decoupled patterns of variation across the bone, we analysed whole-bone shape, diaphyseal and epiphyseal shape. We also tested whether traditional aerodynamic wing traits correlate with humeral shape. By studying 37 species from 20 families (covering all FGs and 85% of dietary guilds), we found similar patterns of variation in whole-bone and diaphyseal shape and unique variation patterns in epiphyseal shape. Phylogeny, diet and FG significantly correlated with shape variation at all levels, whereas size only had a significant effect on epiphyseal morphology. We found a significant phylogenetic signal in all levels of humeral shape. Epiphyseal shape significantly correlated with wing AR. Statistical support for a diaphyseal-epiphyseal modular partition of the humerus suggests a functional partition of shape variability. Our study is the first to show within-structure modular morphological variation in the appendicular skeleton of any living tetrapod. Our results suggest that diaphyseal shape correlates more with phylogeny, whereas epiphyseal shape correlates with diet and FG.

Understanding feeding ecology of extinct kangaroos is fundamental to understanding the evolution of kangaroos and the Australia paleoenvironment during the Oligo-Miocene. Comparisons with extant species have suggested that the macropodiforms of the Oligo/Miocene (kangaroos and allies) from the Riversleigh World Heritage Area, northern Australia, were predominantly folivorous browsers or fungivores, unlike the majority of extant species. To further test this hypothesis, we investigate the relationship between variation in cranial and mandibular shape of extant and extinct macropodiforms and ecological factors such as diet, locomotion, and body mass using 3D geometric morphometric analysis of 42 living species and eight extinct species from two radiations (the extinct clade of Balbaridae and some early representatives of the extant Macropodidae. Dietary class (fungivore, browser, grazer, and mixed feeder) correlated strongly with variation in cranial shape (20–25% of variance explained). There was also significant association between cranial shape, and both locomotor mode and body mass. In a principal component analysis of shape variation for crania (including the shape of the molar row), Riversleigh macropodiforms cluster with extant folivorous browsers on principal components (PC) 1 and 3, providing support for previous interpretations of these species as browsing kangaroos. However, as a group and regardless of phylogenetic association, the shape centroid of extinct species differs significantly from that of extant species. Riversleigh macropodiforms cluster with regular hoppers or arboreal tree kangaroos, but this may be a result of the correlation between diet and locomotor mode in kangaroos. Their similarity to extant browsers supports previous interpretations of rainforest and woodland environments at Riversleigh during the early and middle Miocene, respectively. Procrustes ANOVA Analysis of the full shape dataset and diet also shows that diet accounts for a significant portion of variation; however, when phylogeny is taken into account these results become nonsignificant. In analyses of dentary shape, some balbarid species cluster with extant mixed feeders, although this may reflect phylogenetic differences rather than ecological signal.

Diet has been linked to the diversification of the bat superfamily Noctilionoidea, a group that underwent an impressive ecological adaptive radiation within Mammalia. For decades, studies have explored morphological adaptations and diversity of noctilionoid bats to reveal traits associated with their ecological diversity. Surprisingly, despite such interest and recent application of novel techniques, ecomorphological studies have failed to fully resolve the link between diet and a critical component of the feeding apparatus: dental morphology. Using multivariate dental topographic analysis and phylogenetic comparative methods, we examined the phylogenetic, biological and ecological signal in the dental morphology of noctilionoid bats. Analysing the lower first molars of 110 species, we explored relationships between diet and dental morphology, accounting for three different dimensions of diet (guild, composition and breadth). Phylogenetic and size-dependent structuring of the dental topography data shows it does not correlate only to diet, highlighting the need to account for multiple sources of variation. Frugivorous noctilionoids have sharper molars than other previously reported frugivorous mammals. Nectarivorous noctilionoids showed reduced lower molar crown height and steepness, whereas animalivorous species had larger molars. Dietary composition suggested that the intensity of exploitation of a resource is also linked to different dimensions of dental morphology. Increasing carnivory positively correlated with MA, explaining the highest proportion of its variation, and increasing frugivory explained the highest proportion of variation in all other variables. Dietary breadth showed generalist species have sharper, more topographically-complex molars, whereas specialist herbivores and specialist animalivores fell at opposite ends in the range of tooth steepness and crown height. Together, the results suggest that adaptations affecting different attributes of dental morphology likely facilitated the dietary diversity and specialisation found in Noctilionoidea.

The analysis of regional scale patterns of diversity allows insights into the processes that have shaped modern biodiversity at the macro‐scale. Previous analyses studying biogeographic regionalisation across different high‐level taxa have shown similar trends at a global scale. However, incorporating phylogenetic methods when comparing biogeographic regionalisation between subgroups facilitates identification of mechanisms leading to the biogeographic distribution of specific taxa. We analysed the spatial trends of phylogenetic diversity and phylogenetic endemism of 325 species of New World bats, using updated range maps of the modern distributions. These analyses showed phylogeographic signals that reflect the different evolutionary histories of these families. Zoogeographical zones were detected based on range‐weighted phylogenetic turnover. Values of high phylogenetic diversity and endemism were distributed differently across families, suggesting niche conservatism, but a general latitudinal trend of diversity was evident across taxa. Overall, two main bioregions were shared across New World bat taxa (Nearctic and Neotropical), with two additional subregions (Andean and La Platan). We found strong support for an additional transitional zone in the Pacific coast of South America for Emballonuridae and Molossidae. Differences in regionalisation across families indicate that niche conservatism, in situ diversification and dispersal ability are major drivers for the regionalisation of New World bats, within a dual‐centre of diversification scenario. We also found strong inter‐familial support for an independent Caribbean biogeographic region.

Bats use their forelimbs in different ways, but flight is the most notable example of morphological adaptation. Foraging and roosting specializations beyond flight have also been described in several bat lineages. Understanding postcranial evolution during the locomotory and foraging diversification of bats is fundamental to understanding bat evolution. We investigated whether different foraging and roosting behaviors influenced humeral cross-sectional shape and biomechanical variation, following Wolff's law of bone remodeling. The effect of body size and phylogenetic relatedness was also tested, in order to evaluate multiple sources of variation. Our results suggest strong ecological signal and no phylogenetic structuring in shape and biomechanical variation in humeral phenotypes. Decoupled modes of scaling of shape and biomechanical variation were consistently indicated across foraging and roosting behaviors, suggesting divergent allometric trajectories. Terrestrial locomoting and upstand roosting species showed unique patterns of shape and biomechanical variation across all our analyses, suggesting that these rare behaviors among bats place unique functional demands on the humerus, canalizing phenotypes. Our results suggest that complex and multiple adaptive pathways interplay in the postcranium, leading to the decoupling of different features and regions of skeletal elements optimized for different functional demands. Moreover, our results shed further light on the phenotypical diversification of the wing in bats and how adaptations besides flight could have shaped the evolution of the bat postcranium.

Sheath-tailed bats (Family Emballonuridae) from the early Pleistocene Rackham’s Roost Site cave deposit in the Riversleigh World Heritage Area, north-western Queensland are the oldest recorded occurrence for the family in Australia. The fossil remains consist of maxillary and dentary fragments, as well as isolated teeth, but until now their precise identity has not been assessed. Our study indicates that at least three taxa are represented, and these are distinguished from other Australian emballonurids based on morphometric analysis of craniodental features. Most of the Rackham’s Roost Site emballonurid remains are referrable to the modern speciesTaphozous georgianusThomas, 1915, but the extant speciesT. troughtoniTate, 1952 also appears to be present, as well as a very large, as-yet undetermined species ofSaccolaimusTemminck, 1838. We identify craniodental features that clearly distinguishT. georgianusfrom the externally very similarT. troughtoni. Results suggest that the distributions ofT. georgianusandT. troughtonimay have overlapped in north-western Queensland since at least the early Pleistocene.

The middle Miocene La Venta bat fauna is the most diverse bat palaeocommunity in South America, with at least 14 species recorded. They include the oldest plant-visiting bat in the New World, and some of the earliest representatives of the extant families Phyllostomidae, Thyropteridae and Noctilionidae. La Venta’sNotonycteris magdalenensisis an extinct member of the subfamily Phyllostominae, a group of modern Neotropical animalivorous and omnivorous bats, and is commonly included in studies of the evolution of Neotropical bats, but aspects of its biology remain unclear. In this study, we used a multivariate dental topography analysis (DTA) to reconstruct the likely diet ofN. magdalenensisby quantitatively comparing measures of molar complexity with that of 25 modern phyllostomid and noctilionid species representing all major dietary habits in bats. We found clear differences in molar complexity between dietary guilds, indicating that DTA is potentially an informative tool to study bat ecomorphology. Our results suggestN. magdalenensiswas probably an omnivore or insectivore, rather than a carnivore like its modern relativesChrotopterus auritusandVampryum spectrum. Also, we reconstructed the body mass ofN. magdalenensisto be ∼50 g, which is larger than most insectivorous bats, but smaller than most carnivorous bats. Our results confirm thatNotonycteris magdalenensiswas probably not a specialised carnivore. It remains to be demonstrated that the specialised carnivory ecological niche was occupied by the same lineage of phyllostomines from at least the middle Miocene. Combining our diet and body mass reconstructions, we suggest thatN. magdalenensisexhibits morphological pre-adaptations crucial for the evolution of specialised carnivory.

Current paleontological techniques to separate vertebrate fossils from encasing iron-rich cements by chemical means are limited by the low solubility of common iron(III) hydroxide oxides such as hematite and goethite. This study examines novel geochemical extractions capable of selectively dissolving iron(III) hydroxide oxides, in aqueous solutions of pH 9-11, without damaging fossilised bones or teeth (hydroxidecarbonate-apatite). This involves the siderophore ligands pyridoxal isonicotinoyl hydrazone (PIH), salicylaldehyde isonicotinoyl hydrazone (SIH), and acetohydroxamic acid (aHA), whose coordination complexes with iron(III) show exceptionally high formation stability constants. The methods have been tested on natural hematite and fossil containing samples from the Riversleigh World Heritage Area in Australia. Both 0.01 mol dm-3 aHA and 0.001 mol dm-3 PIH at pH 9.7 were able to dissolve over 0.1 mmol dm-3 of the goethite coating bone fragments.

Quail-thrushes (Passeriformes: Cinclosomatidae: Cinclosoma) are ground-dwelling corvoid songbirds endemic to Australia and New Guinea. Until now, the only known quail-thrush fossils have been from late Quaternary cave deposits in Australia. A new species of quail-thrush, Cinclosoma elachum sp. nov., is described from the early to middle Miocene deposits in the Riversleigh World Heritage Area, Queensland, Australia. A second, larger quail-thrush is identified from the middle Miocene of Riversleigh. The new fossils considerably extend the geographic and temporal ranges of cinclosomatids, and indicate the presence of two species of quail-thrushes in the Miocene of northern Australia, located more than 300 km from the nearest extant member of Cinclosoma. These fossils provide a minimum age of ~18 million years for Cinclosomatidae. They cannot be confidently assigned to the crown group of the genus Cinclosoma, but can be used to calibrate the split between this genus and Ptilorrhoa in molecular dating studies of the Corvides radiation and Passeriformes overall. This material also adds to the growing diversity of songbirds identified from the pre-Pleistocene record of Australia, and reemphasises the global significance of the Riversleigh deposits in developing understanding about the early evolutionary history of passerines.

New World bats represent over one third of global bat species and encompass the widest adaptive radiation among bats. Modern bat diversity in the Americas resulted from a mixture of migrations and colonisations of different taxa throughout the Cenozoic. Traditionally, these taxa are conceived as either South or North American, based on the location of their centres of diversification. To better understand the spatial and temporal processes behind modern biogeographic patterns of New World bat fauna, we investigated phylogenetic diversity (PD) and endemism (PE) for 325 American bat species using distribution maps and a species-level phylogenetic supertree of bats. Randomisation tests were used to evaluate the statistical significance of our results, and to derive a categorical analysis of neo- and palaeo-endemism (CANAPE) to deconstruct significant endemism into its different components. PD and PE showed different patterns than those previously reported for New World bats based on traditional measures of diversity. We found multiple centres of significant endemism across the New World for most bat families, extending the hypothesis of dual centres of diversification, previously proposed for Emballonuridae, Phyllostomidae and Mormoopidae, to Molossidae and Vespertilionidae. Our results indicate that Central America and southern North America played important roles in the diversification of New World bats, as did the Andes in the diversification of Vespertilionidae in South America. This article is protected by copyright. All rights reserved.

While known for over a decade to exist, fossil rails of the early Miocene (19–16 Ma) St Bathans Fauna, from the South Island of New Zealand, have not previously been described taxonomically or studied in detail. Here we use qualitative osteological features and analyse measurements from wing and leg bones to determine the number of taxa represented, their flight ability, and the presence and nature of sexual dimorphism within the identified taxa. We describe two new rail species in monospecific genera from the St Bathans Fauna: Priscaweka parvales gen. et sp. nov., which is extremely common, and Litorallus livezeyi gen. et sp. nov., a distinctly larger, uncommon species. Priscaweka parvales exhibited a significant degree of sexual dimorphism and was tiny, being the size of the extinct Chatham Island Rail Cabalus modestus. Both newly described species exhibit skeletal proportions and osteological features that indicate they had reduced wings and were flightless. These observations reveal that flightless ra...

The generic and specific status of fossil kangaroo specimens attributed to Nambaroo and Ganawamaya from the Riversleigh World Heritage Area, Australia, are revised and new material is described. Results indicate that the previously proposed 12 species (eight of Nambaroo and four of Ganawamaya) represent four species from a single genus (Ganawamaya). Previous studies distinguished species of Ganawamaya from Nambaroo in lacking a protostylid on the lower first molar. However, our analyses indicate that the apparent presence/absence of the protostylid is related to the degree of dental wear, being totally worn in older individuals. Unworn specimens from Riversleigh were previously typically attributed to Nambaroo, while worn specimens were most commonly attributed to Ganawamaya. With support from phylogenetic analyses, we refer Riversleigh's N. couperi and N. gillespieae to Ganawamaya. The diagnoses of both genera are revised. We also assign undescribed specimens from the Ngapakaldi Quarry and Leaf Locality, South Australia, to Gan. couperi comb. nov. and Gan. acris, respectively, and describe new material of Gan. acris and Gan. aediculis.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/., A new genus and species of fossil bat is described from New Zealand’s only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa’s endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand’s fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats.

Wakaleo schouteni sp. nov., a dog-sized marsupial lion (Thylacoleonidae), is described from late Oligocene to early Miocene sediments of the Riversleigh World Heritage Area, Queensland, Australia. ...

The Riversleigh World Heritage Area, northwestern Queensland, Australia, contains numerous Oligo-Miocene and Pleistocene fossil bearing deposits. Species of the suborder Macropodiformes (kangaroos and allies) described from Oligo-Miocene sediments at Riversleigh include representatives of all three macropodiform families: Macropodidae, Hypsiprymnodontidae and Balbaridae, a family of extinct fanged kangaroos. Despite extensive taxonomic study, few studies have focused on the ecology of balbarids that are present in Late Oligocene to Late Miocene faunal assemblages. Recently, several macropodiform species from Riversleigh have been described or revised that significantly alter previous interpretations of species richness and abundance at Riversleigh. In this study, Riversleigh macropodiform species richness and relative abundance is explored against a framework of recently revised taxonomic interpretations and biostratigraphy. With the exception of the Early Miocene, our results suggest that balbarids were less abundant than macropodids at Riversleigh. Balbarid species richness declined by the Early Miocene while macropodid species diversity declined from the Early Miocene to Middle Miocene and again in the Late Miocene. We also estimate body mass for macropodiform taxa throughout the Oligo-Miocene. A statistically significant increase in body mass is evident for most taxa through time. A number of ancestral macropodid genera suffer extinction in the Middle Miocene and are replaced by larger sthenurine macropodids around the time of the Miocene Climatic Optimum. Trends in faunal turnover (extinction and replacement of several macropodiform species) in the Middle Miocene are consistent with trends for other mammalian groups both from Riversleigh and globally.

The Riversleigh World Heritage Area in Queensland contains a vast array of Oligocene-Pleistocene vertebrate, invertebrate and plant fossils. The existing suite of fossil deposits contains a number of temporal gaps in the faunal succession, and exploration is turning to large expanses of recently-discovered Cenozoic carbonates to the west and south of Riversleigh. Previous exploration for new deposits has been primarily based on visual detection of bone or tooth fragments in outcrops or by excavation of sites where lithofacies or mineralogy indicates potential host structures. This study examines the application of field-portable X-ray fluorescence spectrometry (fpXRF) to detecting lithogeochemical or mineralogical indicators of fossil fragments and host structures where visual indicators are absent or subtle. Elemental analysis of outcrops by fpXRF has permitted geochemical differentiation of Cenozoic from underlying Cambrian limestones using Sr/Ca and Mn/Ca ratios. Potentially productive depositional environments and structures such as caves and palaeo-channels can be mapped using various combinations of Ti, Zr, and other relatively immobile elements associated with heavy minerals. Detection of finely-divided vertebrate fossiliferous materials is also possible, using ratios of U, Zn and Pb against Ca, or simply by detecting elevated P. The provision of real-time lithogeochemical data by fpXRF offers potential to accelerate the current exploration program in the Riversleigh area, at regional to local scales, and the detection of important vertebrate fossil deposits otherwise overlooked using the conventional visual survey methods.

A new Early Eocene bat is described from dental remains recovered from the locality of Premontre in the Paris Basin, northern France. It is referred to the extinct family Archaeonycteridae, whose members are among the oldest and dentally most plesiomorphic bats. The new archaeonycterid is part of the diverse Premontre mammal fauna of the late Ypresian (MP10; 50 Ma) which includes a suite of archaic mammals as well as early representatives of modern mammal families. Like other archaeonycterids, this bat may have been an insectivorous perch hunter in paratropical forests that extended into high latitudes during the Early and Middle Eocene. Archaeonycterids disappear from the fossil record after the Middle Eocene, along with many other archaic mammal groups, probably in response to significant changes in climate and habitats as well as competition from crown group bats possibly better adapted to less predictable conditions.http://zoobank.org/urn:lsid:zoobank.org:act:194C2A09-77A6-460C-93E2-017362FD0DC3

The fossil record provides important information about changes in species diversity, distribution, habitat and abundance through time. As we understand more about these changes, it becomes possible to envisage a wider range of options for translocations in a world where sustainability of habitats is under increasing threat. The Critically Endangered alpine/subalpine mountain pygmy-possum, Burramys parvus (Marsupialia, Burramyidae), is threatened by global heating. Using conventional strategies, there would be no viable pathway for stopping this iconic marsupial from becoming extinct. The fossil record, however, has inspired an innovative strategy for saving this species. This lineage has been represented over 25 Myr by a series of species always inhabiting lowland, wet forest palaeocommunities. These fossil deposits have been found in what is now the Tirari Desert, South Australia (24 Ma), savannah woodlands of the Riversleigh World Heritage Area, Queensland (approx. 24–15 Ma) and savannah grasslands of Hamilton, Victoria (approx. 4 Ma). This palaeoecological record has led to the proposal overviewed here to construct a lowland breeding facility with the goal of monitoring the outcome of introducing this possum back into the pre-Quaternary core habitat for the lineage. If this project succeeds, similar approaches could be considered for other climate-change-threatened Australian species such as the southern corroboree frog ( Pseudophryne corroboree ) and the western swamp tortoise ( Pseudemydura umbrina ). This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

Insular avifaunas have repeatedly spawned evolutionary novelties in the form of unusually large, often flightless species. We report fossils from the Early Miocene St Bathans Fauna of New Zealand that attests to the former existence of a giant psittaciform, which is described as a new genus and species. The fossils are two incomplete tibiotarsi from a bird with an estimated mass of 7 kg, double that of the heaviest known parrot, the kakapo Strigops habroptila . These psittaciform fossils show that parrots join the growing group of avian taxa prone to giantism in insular species, currently restricted to palaeognaths, anatids, sylviornithids, columbids, aptornithids, ciconiids, tytonids, falconids and accipitrids.

Background Self-powered flight is one of the most energy-intensive types of locomotion found in vertebrates. It is also associated with a range of extreme morpho-physiological adaptations that evolved independently in three different vertebrate groups. Considering that development acts as a bridge between the genotype and phenotype on which selection acts, studying the ossification of the postcranium can potentially illuminate our understanding of bat flight evolution. However, the ontogenetic basis of vertebrate flight remains largely understudied. Advances in quantitative analysis of sequence heterochrony and morphogenetic growth have created novel approaches to study the developmental basis of diversification and the evolvability of skeletal morphogenesis. Assessing the presence of ontogenetic disparity, integration and modularity from an evolutionary approach allows assessing whether flight may have resulted in evolutionary differences in the magnitude and mode of development in bats. Results We quantitatively compared the prenatal ossification of the postcranium (24 bones) between bats (14 species), non-volant mammals (11 species) and birds (14 species), combining for the first time prenatal sequence heterochrony and developmental growth data. Sequence heterochrony was found across groups, showing that bat postcranial development shares patterns found in other flying vertebrates but also those in non-volant mammals. In bats, modularity was found as an axial-appendicular partition, resembling a mammalian pattern of developmental modularity and suggesting flight did not repattern prenatal postcranial covariance in bats. Conclusions Combining prenatal data from 14 bat species, this study represents the most comprehensive quantitative analysis of chiropteran ossification to date. Heterochrony between the wing and leg in bats could reflect functional needs of the newborn, rather than ecological aspects of the adult. Bats share similarities with birds in the development of structures involved in flight (i.e. handwing and sternum), suggesting that flight altriciality and early ossification of pedal phalanges and sternum are common across flying vertebrates. These results indicate that the developmental modularity found in bats facilitates intramodular phenotypic diversification of the skeleton. Integration and disparity increased across developmental time in bats. We also found a delay in the ossification of highly adaptable and evolvable regions (e.g. handwing and sternum) that are directly associated with flight performance. Electronic supplementary material The online version of this article (10.1186/s12862-019-1396-1) contains supplementary material, which is available to authorized users.

BackgroundThe Mountain Pygmy-possum (Burramys parvus) is a critically endangered marsupial, endemic to alpine regions of southern Australia. We investigated the diet of a recently discovered population of the possum in northern Kosciuszko National Park, NSW, Australia. This new population occurs at elevations well below the once-presumed lower elevation limit of 1,600 m.Goals and MethodsFaecal material was analysed to determine if dietary composition differed between individuals in the newly discovered northern population and those in the higher elevation southern population, and to examine how diet was influenced by rainfall in the southern population and seasonal changes in resource availability in the northern population.Results and DiscussionThe diet ofB. parvusin the northern population comprised of arthropods, fruits and seeds. Results indicate the diet of both populations shares most of the same invertebrate orders and plant species. However, in the absence of preferred food types available to the southern population, individuals of the northern population opportunistically consumed different species that were similar to those preferred by individuals in higher altitude populations. Differing rainfall amounts had a significant effect on diet, with years of below average rainfall having a greater percentage composition and diversity of invertebrates. Seasonal variation was also recorded, with the northern population increasing the diversity of invertebrates in their diet during the Autumn months when Bogong Moths (Agrotis infusa) were absent from those sites, raising questions about the possum’s dependence on the speciesConclusionsMeasurable effects of rainfall amount and seasonal variation on the dietary composition suggest that predicted climatic variability will have a significant impact on its diet, potentially impacting its future survival. Findings suggest that it is likely thatB. parvusis not restricted by dietary requirements to its current pattern of distribution. This new understanding needs to be considered when formulating future conservation strategies for this critically endangered species.

The Chionoidea are a small, southern hemispheric shorebird clade that today includes the Magellanic Plover (Pluvianellidae) and two species of sheathbills (Chionidae). Here we describe the first fossil remains attributable to this group. The two newly described species, the early Miocene Neilus sansomae gen. et sp. nov. from New Zealand and the late Oligocene Chionoides australiensis gen. et sp. nov. from South Australia, are overall more similar to sheathbills, but the mosaic of characters shared with both Chionidae and Pluvianellidae preclude referral to either lineage. Attribution of fossils this age to these lineages also conflicts with divergence dates based on molecular data, as the split between the Magellanic Plover and sheathbills is hypothesised to be more recent. We therefore suggest that these Australasian, plover-size species represent the first record of stem-group taxa within Chionoidea.http://zoobank.org/urn:lsid:zoobank.org:pub:2A5A2FD1-C3B5-4BAB-88D8-5862FE9E7976

Wilson, L.A.B., Hand, S.J., Lopez-Aguirre, C., Archer, M., Black, K.H., Beck, R.M.D., Armstrong, K.N. & Wroe, S., July 2016. Cranial shape variation and phylogenetic relationships of extinct and extant Old World leaf-nosed bats. Alcheringa 40, 509–524. ISSN 0311-5518The leaf-nosed bats in Hipposideridae and Rhinonycteridae currently have an Old World tropical to subtropical distribution, with a fossil record extending back to the middle Eocene of Europe. The Riversleigh World Heritage fossil site in northwestern Queensland constitutes a particularly rich archive of faunal diversity for Old World leaf-nosed bats, having yielded more than 20 species. We used 2D geometric morphometrics to quantify cranial shape in hipposiderids and rhinonycterids, with the aim of referring unallocated fossil species, particularly from Riversleigh, to each family within a phylogenetic framework, and using a quantitative approach to reconstruct cranial shape for key clades in these Old World radiations. Our sample comprised 21...

Binfield, P., Archer, M., Hand, S.J., Black, K.H., Myers, T.J., Gillespie, A.K. & Arena, D.A., June 2016. A new Miocene carnivorous marsupial, Barinya kutjamarpensis (Dasyuromorphia), from central Australia. Alcheringa 41, xx–xx. ISSN 0311-5518.A new dasyuromorphian, Barinya kutjamarpensis sp. nov., is described on the basis of a partial dentary recovered from the Miocene Wipajiri Formation of northern South Australia. Although about the same size as the only other species of this genus, B. wangala from the Miocene faunal assemblages of the Riversleigh World Heritage Area, northwestern Queensland, it has significant differences in morphology including a very reduced talonid on M4 and proportionately wider molars. Based on the structural differences and the more extensive wear on its teeth, the central Australian species might have consumed harder or more abrasive prey in a more silt-rich environment than its congener, which hunted in the wet early to middle Miocene forests of Riversleigh.Pippa Binfield [p...

Radiometric U–Pb ages are presented for the Riversleigh World Heritage fossil mammal site in northwestern Queensland, Australia. The ages are determined on speleothems which are generally found in intimate or well-documented association with fossil remains and thus can be assumed to record the age of the latter with a high degree of confidence. The new ages encompass the early (18.2–16.5 Ma) and middle Miocene (15.1–13.5 Ma) deposits at Riversleigh in addition to the younger Rackham's Roost Site which returns early Pleistocene ages. Together, these provide a robust chronological framework for the interpretation of Neogene biotic change in Australia that has, until now, relied almost entirely upon biocorrelative techniques. In particular they permit closer investigation of links between other regions/faunas and allow comparison with other records of climatic and environmental change. This is the first documented example of a methodology that has widespread potential application across many continents and throughout much of Earth history.

We present the first detailed descriptions of postcranial elements of the fossil marsupial mole Naraboryctes philcreaseri (Marsupialia: Notoryctemorphia), from early Miocene freshwater limestone deposits in the Riversleigh World Heritage Area, northwestern Queensland. Qualitative functional analysis of these elements suggest that Na. philcreaseri was very well-adapted for burrowing, albeit somewhat less so than the living marsupial moles Notoryctes typhlops and N. caurinus. Quadratic discriminant analysis of limb measurements suggests that Na. philcreaseri was subterranean, and its Index of Fossorial Ability is almost identical to that of Notoryctes species, being among the highest known for any mammal. These results suggest that notoryctemorphians evolved their specialised, “mole-like” subterranean lifestyle prior to the early Miocene. Given that forested environments predominated in Australia until the middle-late Miocene, this transition to subterranean behaviour may have occurred via burrowing in forest floors, in which case fossorial mammals that live in tropical rainforests today (such as the placental golden moles Chrysospalax trevelyani and Huetia leucorhina) may represent reasonable living analogues for early notoryctemorphians. However, alternative scenarios, such as a cave-dwelling or semi-aquatic ancestry, should be considered. Phylogenetic analysis using a Bayesian total evidence dating approach places Naraboryctes as sister to Notoryctes with strong support (Bayesian posterior probability = 0.91), and indicates that Naraboryctes and Notoryctes diverged 30.3 MYA (95% HPD: 17.7-46.3 MYA). The age and known morphology of Na. philcreaseri does not preclude its being ancestral to Notoryctes. Using estimates of divergence times and ratios of nonsynonymous to synonymous substitutions per site, we infer that the nuclear gene “Retinol-binding protein 3, interstitial” (RBP3), which plays a key role in vision, became inactive in the Notoryctes lineage ~5.4 MYA (95% HPD: 4.5-6.3 MYA). This is much younger than previous published estimates, and postdates considerably the age of Na. philcreaseri, implying that RBP3 was active in this fossil taxon; hence, Na. philcreaseri may have retained a functional visual system. Our estimate for the inactivation of RBP3 in the Notoryctes lineage coincides with palaeobotanical evidence for a major increase in the abundance of grasses in Australia, which may indicate the appearance of more open environments, and hence selection pressure on notoryctemorphians to spend less time on the surface, leading to relaxed selection on RBP3. Ultimately, however, a fuller understanding of the origin and evolution of notoryctemorphians-including when and why they became “mole-like”-will require improvements in the Palaeogene fossil record of mammals in Australia

Lineage zones within nine contemporaneous mammalian lineages represented in the Cenozoic fossil vertebrate record from the Riversleigh World Heritage Area in northern Australia are used to resolve a series of faunal intervals from the Late Oligocene to Late Miocene. The results agree with previous interpretations of Cenozoic biostratigraphy, provide evidence for the presence of time horizons subdividing some of the four previously recognized Riversleigh biochrons A–D and also provide evidence supporting the allocation of a greater number of Riversleigh faunas to intervals within the Riversleigh biochronology than other methods in previous work. This approach demonstrates the biostratigraphical potential of evolutionary lineages.

New specimens of the late Oligocene macropodiform, Gumardee pascuali, are described, as well as two new late Oligocene to early Miocene species, G. springae sp. nov. and G. richi sp. nov. Species of Gumardee exhibit a unique combination of features, including very long upper and lower third premolars, partially lophodont molars and, in dorsoventral plane, concave lower molar row and convex upper molar row. We combined two morphological matrices to assess the phylogenetic relationships of these species. Our analysis recovered species of Gumardee as a well-supported monophyletic group, nested within Potoroinae. Gumardee richi and G. pascuali appear to be more derived than G. springae in having a more strongly developed posthypocristid that is almost hypolophid-like.

Morphological shifts observed in the fossil record of a lineage potentially indicate concomitant shifts in ecology of that lineage. Mekosuchine crocodiles of Cenozoic Australia display departures from the typical eusuchian body-plan both in the cranium and postcranium. Previous qualitative studies have suggested that these crocodiles had a more terrestrial habitus than extant crocodylians, yet the capacity of mekosuchine locomotion remains to be tested. Limb bone shape, such as diaphyseal cross-section and curvature, has been related to habitual use and locomotory function across a wide variety of taxa. Available specimens of mekosuchine limbs, primarily humeri, are distinctly columnar compared with those of extant crocodylians. Here we apply a quantitative approach to biomechanics in mekosuchine taxa using both geomorphic morphometric and finite element methods to measure bone shape and estimate locomotory stresses in a comparative context. Our results show mekosuchines appear to diverge from extant semi-aquatic saltwater and freshwater crocodiles in cross-sectional geometry of the diaphysis and generate different structural stresses between models that simulate sprawling and high-walk gaits. The extant crocodylians display generally rounded cross-sectional diaphyseal outlines, which may provide preliminary indication of resistance to torsional loads that predominate during sprawling gait, whereas mekosuchine humeri appear to vary between a series of elliptical outlines. Mekosuchine structural stresses are comparatively lower than those of the extant crocodylians and reduce under high-walk gait in some instances. This appears to be a function of bending moments induced by differing configurations of diaphyseal curvature. Additionally, the neutral axis of structural stresses is differently oriented in mekosuchines. This suggests a shift in the focus of biomechanical optimisation, from torsional to axial loadings. Our results lend quantitative support to the terrestrial habitus hypothesis in so far as they suggest that mekosuchine humeri occupied a different morphospace than that associated with the semi-aquatic habit. The exact adaptational trajectory of mekosuchines, however, remains to be fully quantified. Novel forms appear to emerge among mekosuchines during the late Cenozoic. Their adaptational function is considered here; possible applications include navigation of uneven terrain and burrowing.