Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
1,154
datasets available to search
ShareScore release 0.9.0
Dataset results
1,154 results for “Extant”
Figs 51–58 in New fossil genus and new extant species of diatoms (Stephanodiscaceae, Bacillariophyceae) from Pleistocene sediments in the Neotropics (Guatemala, Central America): adaptation to a changing environment?
Figs 51–58 (next page). Type material of fossil lacustrine diatom Discostella gabinii Paillès & Sylvestre sp. nov., Lake Petén-Itzá (Guatemala); SEM valve views. 51. External valve view showing a colliculate central area with scattered areolae, knots and papillae, and a marginal area with finely punctuated radiating striae. 52. External view of a large specimen with numerous areolae in the central area; the striae have rounded ends near the margin. 53. Valve view of a complete corroded frustule showing valve interior with medium sized alveoli and marginal fultoportulae located in the middle of every 3rd to 5th alveoli; open valvocopula present. 54. External openings of marginal fultoportulae located just below the crescent end of the striae (white arrowheads). 55. Internal valve view with medium sized alveoli and a large expansion of the smooth central lamina; marginal fultoportulae located on every 3rd to 5th alveoli. 56. Internal valve view with smooth central area with a single areola; open valvocopula present. 57. Detail view of valve margin; marginal fultoportulae composed of one tube with two satellite pores positioned on the external ends of the alveoli; rimoportula with vertically orientated lips, located between two costae at the edge of an alveolus and within the ring of marginal fultoportulae. 58. Detail view of the valve margin with an eroded marginal fultoportula at the edge of the alveolus; note a row of fine pores on the interior of the girdle band (white arrowheads). Scale bars = 51–56 = 2 µm; 57–58 = 1 µm.
Figs 33–40 in New fossil genus and new extant species of diatoms (Stephanodiscaceae, Bacillariophyceae) from Pleistocene sediments in the Neotropics (Guatemala, Central America): adaptation to a changing environment?
Figs 33–40 (next page). Type material of fossil lacustrine diatom Cyclocostis rolfii Paillès gen. et sp. nov.; SEM internal valve views. 33. Broken valve revealing internal structure; note the reduced cell cavity (white arrowhead). 34. Valve interior showing strong anastomosing ribs merging to a central siliceous ring; central lamina absent; marginal fultoportulae located on every 2nd recessed costa; note the slightly deflected rimoportula (white arrow). 35. Valve interior of a small specimen with strong thick ribs and reduced alveoli, central lamina absent; note the single valve face fultoportula (white arrowhead) located near the valve margin on the raised central area; open valvocopula in place. 36. Broken valve margin showing complex alveolar structure: two thick ribs with a median recessed costa, more inwardly bent, carrying marginal fultoportula composed of one tube and three satellite pores. 37. Valve interior of a small specimen with valvocopula. 38. Heart shaped alveoli due to the marginal fultoportula located on median recessed costa. 39. Internal valve view with marginal fultoportulae and rimoportula arranged in a ring below the valve margin; the single valve face fultoportula (double white arrowhead) is always on the opposite side from the rimoportula (single white arrowhead). 40. Detail of the single valve face fultoportula composed of a short tube and three satellite pores always in an eccentric position. Scale bars: 33, 34 = 5 µm; 35, 39 = 2 µm; 36–38 = 1 µm; 40 = 0.5 µm.
Data from: Early diversification trend and Asian origin for extant bat lineages
Bats are a unique mammalian group, which belong to one of the largest and most diverse mammalian radiations, but their early diversification is still poorly understood, and conflicting hypotheses have emerged regarding their biogeographic history. Understanding their diversification is crucial for untangling the enigmatic evolutionary history of bats. In this study, we elucidated the rate of diversification and the biogeographic history of extant bat lineages using genus-level chronograms. The results suggest that a rapid adaptive radiation persisted from the emergence of crown bats until the Early Eocene Climatic Optimum, whereas there was a major deceleration in diversification around 35–49 Ma. There was a positive association between changes in the palaeotemperature and the net diversification rate until 35 Ma, which suggests that the palaeotemperature may have played an important role in the regulation of ecological opportunities. By contrast, there were unexpectedly higher diversification rates around 25–35 Ma during a period characterized by intense and long-lasting global cooling, which implies that intrinsic innovations or adaptations may have released some lineages from the intense selective pressures associated with these severe conditions. Our reconstruction of the ancestral distribution suggests an Asian origin for bats, thereby indicating that the current panglobal but disjunct distribution pattern of extant bats may be related to events involving seriate cross-continental dispersal and local extinction, as well as the influence of geological events and the expansion and contraction of megathermal rainforests during the Tertiary.
Data from: Mandible allometry in extant and fossil Balaenopteridae (Cetacea: Mammalia): the largest vertebrate skeletal element and its role in rorqual lunge-feeding
Rorqual whales (crown Balaenopteridae) are unique among aquatic vertebrates in their ability to lunge-feed. During a single lunge, rorquals rapidly engulf a large volume of prey-laden water at high speed, which they then filter to capture suspended prey. Engulfment biomechanics are mostly governed by the coordinated opening and closing of the mandibles at large gape angles, which differentially exposes the floor of the oral cavity to oncoming flow. Mouth area in rorquals is delimited by unfused bony mandibles that form kinetic linkages to each other and with the skull. The relative scale and morphology of these skeletal elements have profound consequences for the energetic efficiency of foraging in these gigantic predators. Here we performed a morphometric study of rorqual mandibles using a dataset derived from a survey of museum specimens. Across adult specimens of extant balaenopterids, mandibles range in size from ~1-6 m in length, and at their upper limit they represent the single largest osteological element of any vertebrate, living or extinct. Our analyses determined that rorqual mandibles exhibit positive allometry, whereby the relative size of these mandibles becomes greater with increasing body size. These robust scaling relationships allowed us to predict mandible length for fragmentary remains (e.g., incomplete and/or fossil specimens), as we demonstrated for two partial mandibles from the latest Miocene of California, U.S.A., and for mandibles from previously described fossil balaenopterids. Furthermore, we showed the allometry of mandible length to body size in extant mysticetes, which hints at fundamental developmental constraints in mysticetes despite their ecomorphologic differences in the feeding styles. Lastly, we outlined how our findings can be used to test hypotheses about the antiquity and evolution of lunge-feeding.
Data from: A new method for reconstructing brain morphology: applying the brain-neurocranial spatial relationship in an extant lungfish to a fossil endocast
Lungfish first appeared in the geological record over 410 million years ago and are the closest living group of fish to the tetrapods. Palaeoneurological investigations into the group show that unlike numerous other fishes—but more similar to those in tetrapods—lungfish appear to have had a close fit between the brain and the cranial cavity that housed it. As such, researchers can use the endocast of fossil taxa (an internal cast of the cranial cavity) both as a source of morphological data but also to aid in developing functional and phylogenetic implications about the group. Using fossil endocast data from a three-dimensional-preserved Late Devonian lungfish from the Gogo Formation, Rhinodipterus, and the brain-neurocranial relationship in the extant Australian lungfish, Neoceratodus, we herein present the first virtually reconstructed brain of a fossil lungfish. Computed tomographic data and a newly developed 'brain-warping' method are used in conjunction with our own distance map software tool to both analyse and present the data. The brain reconstruction is adequate, but we envisage that its accuracy and wider application in other taxonomic groups will grow with increasing availability of tomographic datasets.
Data from: Ventilatory mechanics from maniraptoran theropods to extant birds
Shared behavioural, morphological and physiological characteristics are indicative of the evolution of extant birds from non-avian maniraptoran dinosaurs. One such shared character is the presence of uncinate processes; respiratory structures in extant birds. Recent research has suggested a respiratory role for these processes found in oviraptorid and dromaeosaurid dinosaurs. By measuring the geometry of fossil rib cage morphology we demonstrate that the mechanical advantage, conferred by uncinate processes, for movements of the ribs in the oviraptorid theropod dinosaur, Citipati osmolskae, basal avialan species Zhongjianornis yangi, Confuciusornis sanctus, and the more derived ornithurine Yixianornis grabaui, is of the same magnitude as found in extant birds. These skeletal characteristics provide further evidence of a flow-through respiratory system in non-avian theropod dinosaurs and basal avialans, and indicate that uncinate processes are a key adaptation facilitating the ventilation of a lung air sac system that diverged earlier than extant birds.
Data from: Range-edge genetic diversity: locally poor extant southern patches maintain a regionally diverse hotspot in the seagrass Zostera marina
Refugial populations at the rear edge are predicted to contain higher genetic diversity than those resulting from expansion, such as in post-glacial recolonizations. However, peripheral populations are also predicted to have decreased diversity compared to the center of a species' distribution. We aim to test these predictions by comparing genetic diversity in populations at the limits of distribution of the seagrass Zostera marina, with populations in the species' previously described central diversity 'hotspot'. Zostera marina populations show decreased allelic richness, heterozygosity and genotypic richness in both the 'rear' edge and the 'leading' edge compared to the diversity 'hotspot' in the North Sea / Baltic region. However, when populations are pooled, genetic diversity at the southern range is as high as in the North Sea / Baltic region while the 'leading edge' remains low in genetic diversity. The decreased genetic diversity in these Southern Iberia populations compared to more central populations is possibly the effect of drift due to small effective population size, as a result of reduced habitat, low sexual reproduction and low gene flow. However, when considering the whole southern edge of distribution rather than per population, diversity is as high as in the central 'hotspot' in the North Sea / Baltic region. We conclude that diversity patterns assessed per population can mask the real regional richness that is typical of rear edge populations, which have played a key role in the species biogeographic history and as marginal diversity hotspots have very high conservation value.
Data from: Qualitative skeletal correlates of wing shape in extant birds (Aves: Neoaves)
Background: Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long and narrow vs. short and broad wings. Increasing aspect ratio results in a functional tradeoff between low induced drag (efficient cruise) and increased wing inertia (difficult takeoff). Given the wide scope of its functional effects, the pattern of aspect ratio evolution is an important factor that contributes to the substantial ecological and phylogenetic diversity of living birds. However, because the feathers that define the wingtip (and hence wingspan and aspect ratio) often do not fossilize, resolution in the pattern of avian wing shape evolution is obscured by missing information. Here I use a comparative approach to investigate the relationship between skeletal proxies of flight feather attachment and wing shape. Results: An accessory lobe of the internal index process of digit II-1, a bony correlate of distal primary attachment, shows weak but statistically significant relationships to aspect ratio and mass independent of other skeletal morphology. The dorsal phalangeal fossae of digit II-1, which house distal primaries VIII and IX, also show a trend of increased prominence with higher aspect ratio. Quill knobs on the ulna are examined concurrently, but do not show consistent signal with respect to wing shape. Conclusions: Although quill knobs are cited as skeletal correlates of flight performance in birds, their relationship to wing shape is inconsistent among extant taxa, and may reflect diverging selection pressures acting on a conserved architecture. In contrast, correlates of distal primary feather attachment on the major digit show convergent responses to increasing aspect ratio. In light of the diversity of musculoskeletal and integumentary mophology that underlies wing shape in different avian clades, it is unlikely that a single skeletal feature will show consistent predictive power across Neoaves. Confident inference of wing shape in basal ornithurine birds will require multiple lines of evidence, together with an understanding of clade-specific evolutionary trends within the crown.
Data from: Cats in the forest: predicting habitat adaptations from humerus morphometry in extant and fossil Felidae (Carnivora)
Mammalian carnivores are rarely incorporated in paleoenvironmental reconstructions, largely because of their rarity within the fossil record. However, multivariate statistical modeling can be successfully used to quantify specific anatomical features as environmental predictors. Here we explore morphological variability of the humerus in a closely related group of predators (Felidae) to investigate the relationship between morphometric descriptors and habitat categories. We analyze linear measurements of the humerus in three different morphometric combinations (log-transformed, size-free, and ratio), and explore four distinct ways of categorizing habitat adaptations. Open, Mixed, and Closed categories are defined according to criteria based on traditional descriptions of species, distributions, and biome occupancy. Extensive exploratory work is presented using linear discriminant analyses and several fossils are included to provide paleoecological reconstructions. We found no significant differences in the predictive power of distinct morphometric descriptors or habitat criteria, although sample splitting into small and large cat guilds greatly improves the stability of the models. Significant insights emerge for three long-canine cats: Smilodon populator, Paramachairodus orientalis, and Dinofelis sp. from Olduvai Gorge (East Africa). S. populator and P. orientalis are both predicted to have been closed-habitat adapted taxa. The false "sabertooth" Dinofelis sp. from Olduvai Gorge is predicted to be adapted to mixed habitat. The application of felid humerus ecomorphology to the carnivoran record of Olduvai Gorge shows that the older stratigraphic levels (Bed I, 1.99–1.79 Ma) included a broader range of environments than Beds II or V, where there is an abundance of cats adapted to open environments.
Data from: Morphological analysis of phylogenetic relationships among extant rhynchonellide brachiopods
Rhynchonellida is the stratigraphically oldest and phylogenetically most basal of the extant rhynchonelliform brachiopod orders, yet phylogenetic relationships among rhynchonellides are poorly known. The fourteen named rhynchonellide superfamilies (four of which have extant representatives) were defined primarily on the basis of features of the dorsal cardinalia, particularly crural morphology, but their homology and polarity have not been investigated rigorously. Superfamily monophyly is unclear, as is the evolution of several distinctive rhynchonellide morphological features, such as crura. The purpose of this study is to investigate the phylogenetic relationships among extant rhynchonellide genera using skeletal characters, and to compare the results with the current classification, elucidating the evolution of morphological features in the process. We completed parsimony-based and Bayesian analyses using fifty-eight characters of the interior and exterior of the shell that vary among the nineteen extant genera. Our results are readily interpretable with respect to the classification, and indicate that Hemithiridoidea, Dimerelloidea, and (in some analyses) Pugnacoidea appear to be monophyletic. Species classified in Dimerelloidea and Pugnacoidea, and in certain cases Hemithiridoidea, each form derived subclades that evolve from within a paraphyletic Norelloidea at the base of each subclade. Raduliform crura appear to be the most basal, phylogenetically; five other crural morphologies evolve from the raduliform state. However, morphological characters currently uniting genera in rhynchonellide superfamilies are not clearly diagnostic and exhibit a relatively high degree of homoplasy overall, suggesting that consistency with the classification may be based on a false sense of confidence in rhynchonellide morphology to clearly elucidate evolutionary relationships. Published molecular phylogenetic hypotheses conflict with the morphological topologies, further supporting this possibility. The evolutionary trends among diagnostic characters of Recent rhynchonellides appear to reflect successive juvenilization in adult morphology in several subclades, suggesting that heterochrony may have played an important role in the evolution of the group.
Data from: Extant primitively segmented spiders have recently diversified from an ancient lineage
Living fossils are lineages that have retained plesiomorphic traits through long time periods. It is expected that such lineages have both originated and diversified long ago. Such expectations have recently been challenged in some textbook examples of living fossils, notably in extant cycads and coelacanths. Using a phylogenetic approach, we tested the patterns of the origin and diversification of liphistiid spiders, a clade of spiders considered to be living fossils due to their retention of arachnid plesiomorphies and their exclusive grouping in Mesothelae, an ancient clade sister to all modern spiders. Facilitated by original sampling throughout their Asian range, we here provide the phylogenetic framework necessary for reconstructing liphistiid biogeographic history. All phylogenetic analyses support the monophyly of Liphistiidae and of eight genera. As the fossil evidence supports a Carboniferous Euramerican origin of Mesothelae, our dating analyses postulate a long eastward over-land dispersal towards the Asian origin of Liphistiidae during the Palaeogene (39–58 Ma). Contrary to expectations, diversification within extant liphistiid genera is relatively recent, in the Neogene and Late Palaeogene (4–24 Ma). While no over-water dispersal events are needed to explain their evolutionary history, the history of liphistiid spiders has the potential to play prominently in vicariant biogeographic studies.
Fig. 116 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 116. Ventromedial views of left petrosals of Equus caballus (SB MP 55) (Perissodactyla, Hippomorpha) and Tapirus terrestris (AMNH-VP 14103/1587) (Perissodactyla, Ceratomorpha). Dorsomedial and ventrolateral surfaces are gray.
Fig. 117 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 117. Anterior views of left petrosals of Equus caballus (SB MP 55) (Perissodactyla, Hippomorpha) and Tapirus terrestris (AMNH-VP 14103/1587) (Perissodactyla, Ceratomorpha). Ventrolateral surface is gray.
Fig. 70 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 70. Ventromedial views of left petrosals of †Elomeryx armatus (AMNH-VP 579), (†Anthracotherioidea, †Anthracotheriidae), †Merycoidodon sp. (AMNH-VP LUSK 0781572) (†Oreodontoidea, †Oreodontidae), and †Archaeotherium sp. (AMNH-VP 96433) (†Entelodontoidea, †Entelodontidae). Dorsomedial and ventrolateral surfaces are gray.
Fig. 94 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 94. Ventrolateral (tympanic) views of left petrosal Ziphius cavirostris (AMNH-M 70378) (Cetacea, Odonotoceti). Striped areas indicate attached tympanic bulla. Scale 5 1 cm.
Fig. 43 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 43. Tympanic contacts with ventrolateral petrosal for Choeropsis liberiensis (UCR 3116) (Cetancodonta, Hippopotamidae), Hipppotamus amphibius (AMNH-M 24289) (Cetancodonta, Hippopotamidae), Potamochoerus porcus (AMNH-M 238329) (Suina, Suidae), and Sus scrofa (AMNH-M 254518) (Suina, Suidae). Hatched areas are fused bulla.
Fig. 36 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 36. Ventromedial views of left petrosals of Camelus dromedarius (SBU MAR 31) (Camelidomorpha, Camelidae), †Poebrotherium sp. (AMNH-VP 140343) (Camelidomorpha, Camelidae), and †Protoceras celer (AMNH-VP 645) (†Protoceratidae). Dorsomedial and ventrolateral surfaces are gray.
Fig. 4 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 4. Tympanic contacts with ventrolateral petrosals of †Protungulatum sp. (AMNH-VP 118359), Tragulus napu (AMNH-M 102872) (Ruminantia, Tragulidae), †Leptomeryx sp. (AMNH-VP 53786) (Ruminantia, †Leptomerycidae), and Antilocapra americana (UCM VZ 96100) (Ruminantia, Antilocapridae). Damaged areas are hatched. Dotted lines are estimated contacts.
Fig. 35 in An Anatomical And Phylogenetic Study Of The Osteology Of The Petrosal Of Extant And Extinct Artiodactylans (Mammalia) And Relatives
Fig. 35. Dorsolateral views of left petrosals of Camelus dromedarius (SBU MAR 31) (Camelidomorpha, Camelidae), †Poebrotherium sp. (AMNH-VP 140343) (Camelidomorpha, Camelidae), and †Protoceras celer (AMNH-VP 645) (†Protoceratidae). Dorsomedial and ventrolateral surfaces are gray.
FIGURE 60. Umbrina coroides Cuvier 1830, MCUC ZOO.0000033, 330 in The fish collection of José Mariano da Conceição Veloso (1742-1811) and the beginning of ichthyological research in Brazil, with a taxonomic description of the extant specimens
FIGURE 60. Umbrina coroides Cuvier 1830, MCUC ZOO.0000033, 330 mm SL. Photo by Luis M. P. Ceríaco.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.