Chitinozoan biozonation in the upper Katian and Hirnantian of the Welsh Basin, UK

AbstractHere we present a chitinozoan biostratigraphical framework for the South Wales upper Katian and Hirnantian (Ashgill) succession. The current study indicates that three of the six Avalonian Ashgill chitinozoan biozones are recognised in the Welsh Basin; the bergstroemi, fossensis and umbilicata biozones. The Baltoscandian and Laurentian Hercochitina gamachiana biozone is suggested by the presence of Belonechitina cf. gamachiana and the Spinachitina taugourdeaui biozone is suggested by Spinachitina cf. taugourdeaui. Intervening between these is a newly erected lower Hirnantian regional biozone, the Belonechitina llangrannogensis n. sp. biozone. The late Katian (Cautleyan–Rawtheyan) Conochitina rugata biozone was not recognised, though the index taxon is recorded. The presence of B. cf. gamachiana below the lithological expression of the Hirnantian glacial maximum and alongside Rawtheyan graptolite and trilobite assemblages shows that the local base of the B. cf. gamachiana biozone lies beneath the Katian–Hirnantian boundary. Although at present in open nomenclature, the finds of B. cf. gamachiana and S. cf. taugourdeaui, from sites where these chitinozoans co-occur with graptolites, are potentially important; the area offers the potential to study how B. cf. gamachiana and S. cf. taugourdeaui are taxonomically and stratigraphically linked to the original index species. A composite Katian–Hirnantian chitinozoan biozonation for the Welsh Basin is presented and three new species are defined: Belonechitina llangrannogensis n. sp., Belonechitina ceregidionensis n. sp. and Spinachitina penbryniensis n. sp

Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland

Dinosaur fossils from the Middle Jurassic are rare globally, but the Isle of Skye (Scotland, UK) preserves a varied dinosaur record of abundant trace fossils and rare body fossils from this time. Here we describe two new tracksites from Rubha nam Brathairean (Brothers’ Point) near where the first dinosaur footprint in Scotland was found in the 1980s. These sites were formed in subaerially exposed mudstones of the Lealt Shale Formation of the Great Estuarine Group and record a dynamic, subtropical, coastal margin. These tracksites preserve a wide variety of dinosaur track types, including a novel morphotype for Skye: Deltapodus which has a probable stegosaur trackmaker. Additionally, a wide variety of tridactyl tracks shows evidence of multiple theropods of different sizes and possibly hints at the presence of large-bodied ornithopods. Overall, the new tracksites show the dinosaur fauna of Skye is more diverse than previously recognized and give insight into the early evolution of major dinosaur groups whose Middle Jurassic body fossil records are currently sparse

Ichthyosaurs from the Jurassic of Skye, Scotland

Fossils of Mesozoic vertebrates are rare in Scotland, particularly specimens of marine reptiles such as plesiosaurs and ichthyosaurs. We describe a suite of ichthyosaur fossils from the Early to Middle Jurassic of Skye, which to our knowledge are the first ichthyosaurs from Scotland to be described and figured in detail. These fossils span approximately 30 million years, from the Sinemurian to the Bathonian, and indicate that ichthyosaurs were a major component of Scottish marine faunas during this time. The specimens include isolated teeth that could represent the most northerly known occurrences of the widespread Sinemurian species Ichthyosaurus communis, a characteristic component of the famous Lyme Regis faunas of England, suggesting that such faunas were also present in Scotland during the Early Jurassic. An associated humerus and vertebrae from Toarcian–Bajocian-aged deposits are named as a new genus and species of basal neoichthyosaurian, Dearcmhara shawcrossi. The taxonomic affinities of this taxon, which comes from a critical but poorly sampled interval in the fossil record, suggest that non-ophthalmosaurid neoichthyosaurians dominated European assemblages around the Early–Middle Jurassic boundary, and were later replaced by ophthalmosaurids, whose radiation likely took place outside Europe. Many of these specimens were collected by amateurs and donated to museum collections, a co-operative relationship essential to the preservation of Scotland’s fossil heritage

Thinking falls - taking action: development of a guide to action for falls prevention tool (GtA)

Clinical guidelines and research papers help clinicians measure and understand the risk of falling in their older clients but very few provide the assessor with recommendations as to which interventions they can use to reduce the risk of a fall. The Guide to Action for Falls Prevention tool (GtA) was developed to help professionals from a broad range of organisations to recognise factors that might increase falls risk and know which actions to take to lessen that risk. Twenty four professionals tested the GtA in a clinical setting and found it quick (15 mins) and easy to complete. The GtA needs further evaluation to test whether it is a practical way of delivering a falls prevention intervention

Data from: The cranial endocast of Dipnorhynchus sussmilchi (Sarcopterygii: Dipnoi) and the interrelationships of stem-group lungfishes

The first virtual cranial endocast of a lungfish from the Early Devonian, Dipnorhynchus sussmilchi, is described. Dipnorhynchus, only the fourth Devonian lungfish for which a near complete cranial endocast is known, is a key taxon for clarifying primitive character states within the group. A ventrally-expanded telencephalic cavity is present in the endocast of Dipnorhynchus demonstrating that this is the primitive state for “true” Dipnoi. Dipnorhynchus also possesses a utricular recess differentiated from the sacculolagenar pouch like that seen in stratigraphically younger lungfish (Dipterus, Chirodipterus, Rhinodipterus), but absent from the dipnomorph Youngolepis. We do not find separate pineal and para-pineal canals in contrast to a reconstruction from previous authors. We conduct the first phylogenetic analysis of Dipnoi based purely on endocast characters, which supports a basal placement of Dipnorhynchus within the dipnoan stem group, in agreement with recent analyses. Our analysis demonstrates the value of endocast characters for inferring phylogenetic relationships

Data from: The cranial endocast of Dipnorhynchus sussmilchi (Sarcopterygii: Dipnoi) and the interrelationships of stem-group lungfishes

The first virtual cranial endocast of a lungfish from the Early Devonian, Dipnorhynchus sussmilchi, is described. Dipnorhynchus, only the fourth Devonian lungfish for which a near complete cranial endocast is known, is a key taxon for clarifying primitive character states within the group. A ventrally-expanded telencephalic cavity is present in the endocast of Dipnorhynchus demonstrating that this is the primitive state for “true” Dipnoi. Dipnorhynchus also possesses a utricular recess differentiated from the sacculolagenar pouch like that seen in stratigraphically younger lungfish (Dipterus, Chirodipterus, Rhinodipterus), but absent from the dipnomorph Youngolepis. We do not find separate pineal and para-pineal canals in contrast to a reconstruction from previous authors. We conduct the first phylogenetic analysis of Dipnoi based purely on endocast characters, which supports a basal placement of Dipnorhynchus within the dipnoan stem group, in agreement with recent analyses. Our analysis demonstrates the value of endocast characters for inferring phylogenetic relationships

Exploring the location and function of a Late Neolithic house at Crossiecrown, Orkney by geophysical, geochemical and soil micromorphological methods

Magnetic prospection was instrumental in the discovery of a multi-phase Neolithic settlement at Crossiecrown on Mainland Orkney. Subsequent excavation revealed a number of structures, including a large circular walled house of Late Neolithic date with a range of well-defined architectural features in its interior. This paper presents the discovery, excavation and in particular the functional analysis of this house. Soil micromorphology established the sequence from the house’s initial floor construction to its abandonment. On the basis of multi-element and magnetic susceptibility data obtained from analysis of samples taken from the floor of the house, several element distributions were found to be distinctive in the way they correlated with some of the house’s ‘fixed furniture’ and moreover with the distributions of certain artefacts, notably the stone tools. The archaeological implications of these findings are discussed

Organic-carbon deposition and coastal upwelling at mid-latidude during the Upper Ordovician (Late Katian): a case study from the Welsh Basin, UK

A lack of stratigraphical, sedimentological and geochemical data for sediment accumulation rates and indicators of productivity and anoxia means that causative models for ancient black shales are largely inferred from modern settings. Coastal upwelling has been suggested as a general hypothesis for Ordovician black shale deposition within the Iapetus Ocean, but has not been directly tested. Despite anchizone metamorphism we utilize a suite of geological and geochemical environmental proxy data (TOC wt.%, δ13Corg, Ba/Al, P) to elucidate the mechanism for the origin of a single grey-black shale cycle within the upper Katian succession of the Welsh Basin. Here we interpret organic carbon (OC)-rich deposition to be suggestive of a period of high photic productivity (higher TOC wt.%), with 12C and Ba enrichment, comparable to high productivity events in modern coastal upwelling systems. Productivity proxy values are consistent with those from margins where sedimentation rates are high (e.g. Gulf of California). Inter-bedded grey shales have low TOC wt.% more positive δ13Corg and marginally lower Ba and are interpreted as low productivity events. Thalassinoides, Planolites and Chondrites ichnofacies indicate changing seafloor oxygen levels. These show predominantly dysoxic conditions even during the deposition of OC-poor grey shales. During an OC-rich laminated hemipelagite event, oxygen levels declined at the sea floor before the deposition of the OC-rich layers. Full anoxia was established early on in the deposition of OC-rich layers and the return to more oxic conditions was rapid though fluctuating and coincident with the return of grey shale deposition. This pattern suggests OC accumulation at the seafloor resulted from a complex interaction of productivity and preservation. None of the widely used trace element redox proxies are reliable in anchizone metamorphic rocks. Climate sensitive detrital proxies (K/Al and Ti/Al) indicate arid–temperate conditions in the basin hinterland during the deposition of the OC-rich layers. The Welsh Basin was situated on the southern margin of the Iapetus Ocean in (30°S) beneath the prevailing SE trade winds. We interpret the occurrence of OC-rich laminated hemipelagite events to represent the intensification of upwelling, prior to the Hirnantian glaciation, possibly having resulted from a strengthening of the trade winds, associated with stepped changes in ice volume, and a more arid local climate

Data from: The cranial endocast of Dipnorhynchus sussmilchi (Sarcopterygii: Dipnoi) and the interrelationships of stem-group lungfishes

The first virtual cranial endocast of a lungfish from the Early Devonian, Dipnorhynchus sussmilchi, is described. Dipnorhynchus, only the fourth Devonian lungfish for which a near complete cranial endocast is known, is a key taxon for clarifying primitive character states within the group. A ventrally-expanded telencephalic cavity is present in the endocast of Dipnorhynchus demonstrating that this is the primitive state for “true” Dipnoi. Dipnorhynchus also possesses a utricular recess differentiated from the sacculolagenar pouch like that seen in stratigraphically younger lungfish (Dipterus, Chirodipterus, Rhinodipterus), but absent from the dipnomorph Youngolepis. We do not find separate pineal and para-pineal canals in contrast to a reconstruction from previous authors. We conduct the first phylogenetic analysis of Dipnoi based purely on endocast characters, which supports a basal placement of Dipnorhynchus within the dipnoan stem group, in agreement with recent analyses. Our analysis demonstrates the value of endocast characters for inferring phylogenetic relationships.Clement, A.M. et al. (2016), Data from: The cranial endocast of Dipnorhynchus sussmilchi (Sarcopterygii: Dipnoi) and the interrelationships of stem-group lungfishes, Dryad, Dataset, 10.5061/dryad.22dr