A new icriodontid conodont cluster with specific mesowear supports an alternative apparatus motion model for Icriodontidae

Increasing numbers of conodont discoveries with soft tissue preservation, natural assemblages and fused clusters of the hard tissue have strengthened the hypothesis regarding the function and mechanism of the conodont feeding apparatus. Exceptional fossil preservation serves as a solid basis for modern reconstructions of the conodont apparatus illustrating the complex interplay of the single apparatus elements. Reliable published models concern the ozarkodinid apparatus of Pennsylvanian and Early Triassic conodonts. Recognition of microwear and mammal-like occlusion, especially of platform elements belonging to individuals of the genus Idiognathodus, allows rotational closure to be interpreted as the crushing mechanism of ozarkodinid platform (P1) elements. Here we describe a new icriodontid conodont cluster of Caudicriodus woschmidti that consists of one pair of icriodontan (I) and 10 pairs of coniform (C1\ue2\u80\u935) elements, with I elements being preserved in interlocking position. The special kind of element arrangement within the fused cluster provides new insights into icriodontid apparatus reconstruction and notation of elements. However, orientation of coniform elements is limited to a certain degree by possible preservational bias. Four possible apparatus models are introduced and discussed. Recognition of specific wear on denticle tips of one of the icriodontan elements forms the basis for an alternative hypothesis of apparatus motion. Analysis of tip wear suggests a horizontal, slightly elliptical motion of opposed, antagonistically operating I elements. This is supported by similar tip wear from much better preserved, but isolated, elements of Middle Devonian icriodontids. More detailed interpretation of the masticatory movement will allow enhanced understanding of anatomical specifications, diet and palaeobiology of different euconodont groups

Devonian shallow-water sequences from the North Gondwana coastal margin (Central and Eastern Taurides, Turkey): Sedimentology, facies and global events

Turkey is an integral part of the Alpine-Himalayan orogenic belt with a number of tectonostratigraphic units striking in an E-W direction. These belts consist of terranes of different tectonic settings, ranging from oceanic basins to active and passive continental margins. The age of incorporated units of continental margin origin ranges from the Cambrian to the Cenozoic, and includes unmetamorphosed to low-grade Devonian rocks in the Pontides, Taurides and on the Arabian Plate. This paper describes the detailed sedimentology, facies and biostratigraphy of three 900 to 1200 m thick Devonian successions in the Central and Eastern Taurides (Eceli, Halevikdere and Kocadere). During the Devonian, the Central and Eastern Taurides were situated at the northern margin of Gondwana. The sediments described were deposited on this margin in coastal to shelf environments. Despite similar large-scale trends, regional differences in the sedimentary sequences can be distinguished, especially for the lower part of the Devonian. For the first time, sufficient biostratigraphical data have been recovered to allow the successions to be subdivided at a stage scale, permitting their approximate correlation and comparison with the regional lithostratigraphy. The temporal development of sedimentary processes, facies changes, and hinterland signatures recorded in the individual sections have been reconstructed, allowing their correspondence to global events to be recognized and discussed for the first time. The palaeobiogeographic distribution of various organisms within these succession suggests a comparatively narrow sea ('Rheic Ocean') between Laurasia and Gondwana/Peri-Gondwana during the Devonian. © 2009 International Association for Gondwana Research.Bundesministerium für Bildung und ForschungThis paper is a contribution to DEVEC-TR, a project related to IGCP Project 499 ‘Devonian land–sea interaction: Evolution of ecosystems and climate (DEVEC)’. The TÜBITAK and BMBF are kindly acknowledged for funding the project. Thanks are also due to the technical staff of the participating institutions (Universities of Istanbul, Adana and Mersin, MTA, TPAO, Senckenberg Forschungsinstitute und Naturmuseen) for processing, preparing and analyzing the vast amount of samples taken during the two field campaigns. Comments and remarks of two reviewers improved the paper and are gratefully acknowledged. Alan Lord (Senckenberg Forschungsinstitut und Naturmuseum Frankfurt) is gratefully acknowledged for the helpful comments and linguistic improvements. Appendix

Devonian climate and reef evolution : insights from oxygen isotopes in apatite

Conodonts, microfossils composed of carbonate-fluor apatite, are abundant in Palaeozoic–Triassic sediments and have a high potential to preserve primary oxygen isotope signals. In order to reconstruct the palaeotemperature history of the Devonian, the oxygen isotope composition of apatite phosphate was measured on 639 conodont samples from sequences in Europe, North America and Australia. The Early Devonian (Lochkovian; 416–411 Myr) was characterized by warm tropical temperatures of around 30 °C. A cooling trend started in the Pragian (410 Myr) with intermediate temperatures around 23 to 25 °C reconstructed for the Middle Devonian (397–385 Myr). During the Frasnian (383–375 Myr), temperatures increased again with temperatures to 30 °C calculated for the Frasnian–Famennian transition (375 Myr). During the Famennian (375–359 Myr), surface water temperatures slightly decreased. Reconstructed Devonian palaeotemperatures do not support earlier views suggesting the Middle Devonian was a supergreenhouse interval, an interpretation based partly on the development of extensive tropical coral–stromatoporoid communities during the Middle Devonian. Instead, the Devonian palaeotemperature record suggests that Middle Devonian coral–stromatoporoid reefs flourished during cooler time intervals whereas microbial reefs dominated during the warm to very warm Early and Late Devonian.11 page(s

A Novel SLC6A8 Mutation in a Large Family with X-Linked Intellectual Disability: Clinical and Proton Magnetic Resonance Spectroscopy Data of Both Hemizygous Males and Heterozygous Females

X-linked creatine transport (CRTR) deficiency, caused by mutations in the SLC6A8 gene, leads to intellectual disability, speech delay, epilepsy, and autistic behavior in hemizygous males. Additional diagnostic features are depleted brain creatine levels and increased creatine/creatinine ratio (cr/crn) in urine. In heterozygous females the phenotype is highly variable and diagnostic hallmarks might be inconclusive. This survey aims to explore the intrafamilial variability of clinical and brain proton Magnetic Resonance Spectroscopy (MRS) findings in males and females with CRTR deficiency. X-chromosome exome sequencing identified a novel missense mutation in the SLC6A8 gene (p.G351R) in a large family with X-linked intellectual disability. Detailed clinical investigations including neuropsychological assessment, measurement of in vivo brain creatine concentrations using quantitative MRS, and analyses of creatine metabolites in urine were performed in five clinically affected family members including three heterozygous females and one hemizygous male confirming the diagnosis of CRTR deficiency. The severe phenotype of the hemizygous male was accompanied by most distinct aberrations of brain creatine concentrations (-83% in gray and -79% in white matter of age-matched normal controls) and urinary creatine/creatinine ratio. In contrast, the heterozygous females showed varying albeit generally milder phenotypes with less severe brain creatine (-50% to -33% in gray and -45% to none in white matter) and biochemical urine abnormalities. An intrafamilial correlation between female phenotype, brain creatine depletion, and urinary creatine abnormalities was observed. The combination of powerful new technologies like exome-next-generation sequencing with thorough systematic evaluation of patients will further expand the clinical spectrum of neurometabolic diseases