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Beast Companions
Despite their fame and reputation, dinosaurs represent only half
the story of the Mesozoic Era. In Beast Companions: The Unsung
Animals of the Dinosaurs' World , paleontologist John Foster
explores the often-overlooked animals that coexisted with them.
These ancient species, often equally remarkable as their dinosaur
neighbors, can provide valuable insights into the biotic history of
our planet. In some cases, these animals reveal just as much, if
not more, about the extinct ecosystems of the time as the dinosaurs
themselves.
By drawing on a wealth of current and past discoveries, Foster
embarks on a sweeping journey across 164 million years to visit the
beast companions of the dinosaurs. Along the way, he examines fish,
insects, the first frogs and salamanders, turtles, snakes and
lizards, marine reptiles, crocodiles, pterosaurs, birds, mammals,
and other animals of the Mesozoic Er a.
Beast Companions is a groundbreaking exploration of the
story of these contemporaries of the dinosaurs that set the modern
world in motion more than 200 million years ago
eBook
Aspects of vertebrate paleoecology, taphonomy, and biostratigraphy of the Morrison Formation (Upper Jurassic), Rocky Mountain region, western United States
The Morrison Formation is a deposit of primarily continental sedimentary rocks that is exposed in much of the Rocky Mountain region in the western United States. Diversities, relative abundances, and biomasses of taxa and ecological guilds of the diverse vertebrate paleofauna from this unit were analyzed for variation by stratigraphic level, geographic region, and paleoenvironmental context. Counts of the numbers of specimens of each taxon from more than 200 sites were compiled in order to determine the relative abundances. Within a range of expected variation due to different sample sizes and diversities preserved at certain large quarries, the structure of the paleocommunities in the Morrison Formation appears to have been fairly consistent throughout at least the last 4-6 my, and possibly all of the approximately 8 my of deposition. The diversity of Morrison vertebrate taxa was relatively high and consistent throughout deposition. As nearly as can be determined from death assemblages or trackways, the Morrison Formation paleocommunity was different from any modern community and most ancient ones in having a relatively high abundance and diversity of very large vertebrate animals. Vertebrate biomass appears to have been dominated by large herbivores to an even greater degree than are modern megaherbivore community biomasses, and this may have had an indirect impact on the abundances and diversities of smaller herbivores, small predators, and small non-dinosaurian reptiles. The abundance of microvertebrates in the formation appears to have been reasonably high and may indicate moderately high plant productivity and habitat heterogeneity. In addition to the sauropods, the most common and ecologically important dinosaurs included the ornithopods and the theropod Allosaurus. A paucity of vertebrate prey species in the middle adult weight categories (10-500 kg) may have been caused by competative pressure from juveniles of larger dinosaur species, as well as possibly selective pressure from predators in the middle to large size ranges. The long-ranging non-dinosaurian taxa may have been relatively more abundant in the upper part of the formation and maintained higher diversities there than the long-ranging dinosaurs. Thus, dinosaur diversity may have dropped slightly relative to non-dinosaurs near the end of Morrison deposition.
Dissertation
Structural and functional connectivity in tau mutation carriers: from presymptomatic to symptomatic frontotemporal dementia
INTRODUCTION Microtubule‐associated protein tau (MAPT) mutations cause frontotemporal dementia (FTD), characterised by behavioural, language, and motor impairments due to brain connectivity disruptions. We investigated structural and functional connectivity in 86 mutation carriers and 272 controls to map connectivity changes at different disease stages. METHODS The CDR Dementia Staging Instrument plus National Alzheimer's Coordinating Center (NACC) Behaviour and Language domains (CDR plus NACC FTLD) stratified carriers into three groups: asymptomatic, prodromal, and symptomatic. We extracted measures of cortical thickness, white matter integrity, and functional connectivity, which were compared between each carrier group and controls using linear mixed models. RESULTS Early isolated functional disruptions in salience/visual networks were present in asymptomatic carriers, along with anterior cingulate gray matter reductions. In prodromal carriers, functional changes extended to other networks, with additional structural damage in temporal poles/cingulate. DISCUSSION This study shows that functional networks likely drive lifelong compensation for a genetically determined disease, manifesting clinically when structural damage reaches a critical threshold. This supports connectivity measures as potential biomarkers for MAPT‐related neurodegeneration. Highlights Our findings reveal the progressive and staged nature of structural and functional connectivity alterations in MAPT mutation carriers, with distinct patterns at each disease stage. In asymptomatic carriers, we identified early functional connectivity alterations in salience and visual networks, despite preserved white matter and only subtle gray matter atrophy. These appear to represent both response to pathology and possible compensatory mechanisms. In prodromal carriers, functional connectivity alterations were accompanied by structural damage, including cortical atrophy and white matter tract disruptions, in regions directly connected to early‐affected networks. The sequential progression, from functional connectivity changes to structural degeneration, aligns with the hypothesis that tau propagates along axonal connections, disrupting neural network integrity before measurable atrophy occurs. We propose a theoretical data‐driven model of biomarker evolution in MAPT mutation carriers, highlighting functional disruptions as early indicators and structural damage as a later‐stage hallmark. These connectivity biomarkers have the potential to inform therapeutic strategies and clinical trial design.
Journal Article
New records of injured Cambrian and Ordovician trilobites
Records of abnormal fossil arthropods present important insight into how extinct forms responded to traumatic damage and developmental complications. Trilobites, bearing biomineralized dorsal exoskeletons, have arguably the most well-documented record of abnormalities spanning the Cambrian through the end-Permian. As such, new records of malformed, often injured, trilobites are occasionally identified. To further expand the documentation of abnormal specimens, we describe malformed specimens of Lyriaspis sigillumWhitehouse, 1939, Zacanthoides sp. indet., Asaphiscus wheeleriMeek, 1873, Elrathia kingii (Meek, 1870), and Ogygiocarella debuchii (Brongniart, 1822) from lower Paleozoic deposits. In considering these forms, we propose that they illustrate examples of injuries, and that the majority of these injuries reflect failed predation. We also considered the origin of injuries impacting singular segments, suggesting that these could reflect predation, self-induced damage, or intraspecific interactions during soft-shelled stages. Continued examination of lower Paleozoic trilobite injuries will further the understanding of how trilobites functioned as prey and elucidate how disparate trilobite groups recovered from failed attacks.
Journal Article
White matter hyperintensities precede other biomarkers in GRN frontotemporal dementia
INTRODUCTION Increased white matter hyperintensities (WMHs) have been reported in genetic frontotemporal dementia (FTD) in small studies, but the sequence of WMH abnormalities relative to other biomarkers is unclear. METHODS Using a large dataset (n = 763 GENFI2 participants), we measured WMHs and examined them across genetic FTD variants and stages. Cortical and subcortical volumes were parcellated, and serum neurofilament light chain (NfL) levels were measured. Biomarker progression was assessed with discriminative event‐based and regression modeling. RESULTS Symptomatic GRN carriers showed elevated WMHs, primarily in the frontal lobe, while no significant increase was observed in symptomatic C9orf72 or MAPT carriers. WMH abnormalities preceded NfL elevation, ventricular enlargement, and cortical atrophy. Longitudinally, baseline WMHs predicted subcortical changes, while subcortical volumes did not predict WMH changes, suggesting WMHs may precede neurodegeneration. DISCUSSION WMHs are elevated in a subset of GRN‐associated FTD. When present, they appear early and should be considered in disease progression models. Highlights Elevated WMH volumes are found predominantly in symptomatic GRN. WMH accumulation is mostly observed in the frontal lobe. WMH abnormalities appear early in GRN‐associated FTD, before NfL, atrophy, and ventriculomegaly. Longitudinally, WMH volumes can predict subcortical changes, but not vice versa. WMHs are key early markers in GRN‐associated FTD and should be included in progression models.
Journal Article
Frontoparietal network integrity supports cognitive function in pre‐symptomatic frontotemporal dementia: Multimodal analysis of brain function, structure, and perfusion
INTRODUCTION Genetic mutation carriers of frontotemporal dementia can remain cognitively well despite neurodegeneration. A better understanding of brain structural, perfusion, and functional patterns in the pre‐symptomatic stage could inform accurate staging and potential mechanisms. METHODS We included 207 pre‐symptomatic genetic mutation carriers and 188 relatives without mutations. The gray matter volume, cerebral perfusion, and resting‐state functional network maps were co‐analyzed using linked independent component analysis (LICA). Multiple regression analysis was used to investigate the relationship of LICA components to genetic status and cognition. RESULTS Pre‐symptomatic mutation carriers showed an age‐related decrease in the left frontoparietal network integrity, while non‐carriers did not. Executive functions of mutation carriers became dependent on the left frontoparietal network integrity in older age. DISCUSSION The frontoparietal network integrity of pre‐symptomatic mutation carriers showed a distinctive relationship to age and cognition compared to non‐carriers, suggesting a contribution of the network integrity to brain resilience. Highlights A multimodal analysis of structure, perfusion, and functional networks. The frontoparietal network integrity decreases with age in pre‐symptomatic carriers only. Executive functions of pre‐symptomatic carriers dissociated from non‐carriers.
Journal Article
Multidisciplinary assessment of the Abbott BinaxNOW SARS-CoV-2 point-of-care antigen test in the context of emerging viral variants and self-administration
While there has been significant progress in the development of rapid COVID-19 diagnostics, as the pandemic unfolds, new challenges have emerged, including whether these technologies can reliably detect the more infectious variants of concern and be viably deployed in non-clinical settings as “self-tests”. Multidisciplinary evaluation of the Abbott BinaxNOW COVID-19 Ag Card (BinaxNOW, a widely used rapid antigen test, included limit of detection, variant detection, test performance across different age-groups, and usability with self/caregiver-administration. While BinaxNOW detected the highly infectious variants, B.1.1.7 (Alpha) first identified in the UK, B.1.351 (Beta) first identified in South Africa, P.1 (Gamma) first identified in Brazil, B.1.617.2 (Delta) first identified in India and B.1.2, a non-VOC, test sensitivity decreased with decreasing viral loads. Moreover, BinaxNOW sensitivity trended lower when devices were performed by patients/caregivers themselves compared to trained clinical staff, despite universally high usability assessments following self/caregiver-administration among different age groups. Overall, these data indicate that while BinaxNOW accurately detects the new viral variants, as rapid COVID-19 tests enter the home, their already lower sensitivities compared to RT-PCR may decrease even more due to user error.
Journal Article