Tomographic Reconstruction of Carboniferous Arthropods

Carboniferous fossils are often found as three-dimensional voids within siderite (FeCO3) nodules. Traditional techniques of study – splitting the host concretion and inspecting the surfaces revealed – do not allow the investigation of morphology within the part / counterpart, and prevent complete data recovery. X-ray micro-tomography (XMT) and 'virtual palaeontology' can overcome such limitations. This thesis documents the application of XMT to a number of Carboniferous arthropod groups. In the trigonotarbids (Arachnida: Trigonotarbida) the technique has revealed novel features such as coxal endites and tarsal claws, and allowed a taxonomic revision of the family Anthracomartidae. The harvestmen (Arachnida: Opiliones) have a sparse fossil record, resulting from their poorly sclerotized exoskeleton and terrestriality. Two new species have been reconstructed, greatly expanding morphological data from the early history of the group, and the cladistic assignment of both to extant clades supports molecular estimates of early (Palaeozoic) cladogenesis among the Opiliones. XMT of Compsoscorpius buthiformis (Arachnida: Scorpiones) has allowed a taxonomic revision of numerous Carboniferous scorpions, and provided insight regarding the species' mode of life. XMT analysis of stem-dictyopteran Archimylacris eggintoni (Insecta: Neoptera) – now one of the morphologically best known 'roachoid' fossils – has provided evidence that it was a fast runner, an adept climber and a detritivore. Two new species of insect nymph have also been reconstructed: a heavily spined example is quite unlike any previously described taxa, whereas the other has possible roachoid affinities. The investigation of the enigmatic arthropod Camptophyllia has failed to reveal a sternal surface or appendages, but has nevertheless provided new details of the morphology of this unusual taxon. XMT is a powerful new technique for studying siderite-hosted fossils: it reveals their morphology in great detail, and can inform debates regarding the mode of life, phylogeny, and taxonomy of a wide range of Carboniferous arthropods

Tomographic reconstruction of neopterous Carboniferous insect nymphs

Two new polyneopteran insect nymphs from the Montceau-les-Mines Lagerstätte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One–Anebos phrixos gen. et sp. nov.–is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles’ palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work

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http://archive.org/details/determinationofc00gallN

Assessing the patterns and drivers of shape complexity in the amblypygid pedipalp

Amblypygi is an arachnid order possessing a unique pair of spined pedipalps: appendages that perform in prey capture, courtship, and contest. Pedipalp length, hypothesized to be under sexual selection, varies markedly across amblypygid species, and pedipalp spination, thought to reflect selection for function in prey capture, also differs interspecifically. Differences in pedipalp shape between species may indicate that the relative strength of selection for prey capture and sexual selection vary across the group. However, interspecific differences in pedipalp shape have not been quantified, due to difficulties in identifying homologous features. For the first time, we quantify trends in amblypygid pedipalp shape complexity. We use elliptical Fourier analysis to quantify 2D complexity in pedipalp outlines across eleven species and six genera. We find that complexity significantly decreases as pedipalp length increases. This appears to be driven by relative spine length, suggesting that a trade-off exists between pedipalp length and spination. Furthermore, significant female-biased sexual dimorphism in shape complexity is present in the tibial segment of the amblypygid pedipalp. Our results provide novel insights into the drivers of amblypygid pedipalp evolution and suggest that a functional trade-off between performance in prey capture and other functions under sexual selection exist in this enigmatic structure

The Inter-Rater Consistency of Clinician Ratings of Posttraumatic Stress Disorder (PTSD) Therapy Content.

Effective communication between clinicians is essential for the success of mental health interventions in multidisciplinary contexts. This relies on a shared understanding of concepts, diagnoses and treatments. A major assumption of clinicians when discussing psychological treatments with each other is that both parties have a shared understanding of the theory, rationale and application of the respective technique. We aimed to determine to what extent there is inter-rater agreement between clinicians in describing the content of group therapy sessions. Pairs of clinicians, drawn from a large multidisciplinary team (13), were asked to provide ratings of the therapeutic content and emphasis of N = 154 group therapy sessions conducted during an intensive residential treatment program for post-traumatic stress disorder (PTSD). In most therapeutic content domains there was a moderate level of agreement between clinicians regarding session content (Cohen's Kappa 0.4 to 0.6), suggesting that clinicians have a broad shared understanding of therapeutic content, but that there are also frequent discordant understandings. The implications of these findings on multidisciplinary team communication, patient care and clinical handovers are discussed and directions for further research are outlined

Personal wellbeing in posttraumatic stress disorder (PTSD): Association with PTSD symptoms during and following treatment

© 2018 The Author(s). Background: It remains unclear to what extent treatment-related gains in posttraumatic stress disorder (PTSD) symptoms translate to improvements in broader domains of personal wellbeing, such as community connectedness, life achievement and security. We sought to determine whether: 1. personal wellbeing improves during the course of a treatment program and 2. changes in core symptom domains (PTSD, anxiety and depression) were associated with improvements in overall personal wellbeing. Methods: Participants (N=124) completed the PTSD Checklist, the Depression and Anxiety Stress Scales and the Personal Wellbeing Index at the start and end of a 4-week Trauma Focused CBT residential program, as well as 3- and 9-months post-treatment. Results: Personal wellbeing improved significantly across the 9-months of the study. Generalised estimating equations analyses indicated that (older) age and improvements in PTSD and depressive symptoms were independent predictors of personal wellbeing across time. Conclusions: Although personal wellbeing improved in tandem with PTSD symptoms, the magnitude of improvement was small. These findings highlight a need to better understand how improvements in personal wellbeing can be optimised following PTSD treatment

Almost a spider: a 305-million-year-old fossil arachnid and spider origins

Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasieri gen. et sp. nov. from the Late Carboniferous (Stephanian, ca 305–299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian–Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri. While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies