Global Taxonomic Diversity of Anomodonts (Tetrapoda, Therapsida) and the Terrestrial Rock Record Across the Permian-Triassic Boundary

The end-Permian biotic crisis (∼252.5 Ma) represents the most severe extinction event in Earth's history. This paper investigates diversity patterns in Anomodontia, an extinct group of therapsid synapsids (‘mammal-like reptiles’), through time and in particular across this event. As herbivores and the dominant terrestrial tetrapods of their time, anomodonts play a central role in assessing the impact of the end-Permian extinction on terrestrial ecosystems. Taxonomic diversity analysis reveals that anomodonts experienced three distinct phases of diversification interrupted by the same number of extinctions, i.e. an end-Guadalupian, an end-Permian, and a mid-Triassic extinction. A positive correlation between the number of taxa and the number of formations per time interval shows that anomodont diversity is biased by the Permian-Triassic terrestrial rock record. Normalized diversity curves indicate that anomodont richness continuously declines from the Middle Permian to the Late Triassic, but also reveals all three extinction events. Taxonomic rates (origination and extinction) indicate that the end-Guadalupian and end-Permian extinctions were driven by increased rates of extinction as well as low origination rates. However, this pattern is not evident at the final decline of anomodont diversity during the Middle Triassic. Therefore, it remains unclear whether the Middle Triassic extinction represents a gradual or abrupt event that is unique to anomodonts or more common among terrestrial tetrapods. The end-Permian extinction represents the most distinct event in terms of decline in anomodont richness and turnover rates

Revised Lithostratigraphy of the Sonsela Member (Chinle Formation, Upper Triassic) in the Southern Part of Petrified Forest National Park, Arizona

BACKGROUND: Recent revisions to the Sonsela Member of the Chinle Formation in Petrified Forest National Park have presented a three-part lithostratigraphic model based on unconventional correlations of sandstone beds. As a vertebrate faunal transition is recorded within this stratigraphic interval, these correlations, and the purported existence of a depositional hiatus (the Tr-4 unconformity) at about the same level, must be carefully re-examined. METHODOLOGY/PRINCIPAL FINDINGS: Our investigations demonstrate the neglected necessity of walking out contacts and mapping when constructing lithostratigraphic models, and providing UTM coordinates and labeled photographs for all measured sections. We correct correlation errors within the Sonsela Member, demonstrate that there are multiple Flattops One sandstones, all of which are higher than the traditional Sonsela sandstone bed, that the Sonsela sandstone bed and Rainbow Forest Bed are equivalent, that the Rainbow Forest Bed is higher than the sandstones at the base of Blue Mesa and Agate Mesa, that strata formerly assigned to the Jim Camp Wash beds occur at two stratigraphic levels, and that there are multiple persistent silcrete horizons within the Sonsela Member. CONCLUSIONS/SIGNIFICANCE: We present a revised five-part model for the Sonsela Member. The units from lowest to highest are: the Camp Butte beds, Lot's Wife beds, Jasper Forest bed (the Sonsela sandstone)/Rainbow Forest Bed, Jim Camp Wash beds, and Martha's Butte beds (including the Flattops One sandstones). Although there are numerous degradational/aggradational cycles within the Chinle Formation, a single unconformable horizon within or at the base of the Sonsela Member that can be traced across the entire western United States (the "Tr-4 unconformity") probably does not exist. The shift from relatively humid and poorly-drained to arid and well-drained climatic conditions began during deposition of the Sonsela Member (low in the Jim Camp Wash beds), well after the Carnian-Norian transition

Grass pollen immunotherapy for hayfever is associated with increases in local nasal but not peripheral Th1 : Th2 cytokine ratios

Grass pollen immunotherapy is the only treatment for hayfever that is both effective and confers long-term benefit. Immunotherapy may act by altering the local nasal mucosal T helper type 2 (Th2) to type 1 (Th1) cytokine balance either by down-regulation and/or immune deviation of T-lymphocyte responses. There is controversy as to whether these changes are detectable in peripheral blood. We therefore examined both local nasal and peripheral T-cell responses to allergen exposure in the same subjects before and after immunotherapy. In a double-blind trial of grass pollen immunotherapy, nasal biopsies were obtained at baseline and during the peak pollen season following 2 years of immunotherapy. Placebo-treated patients showed a seasonal increase in CD3(+) T cells (P = 0·02) and in interleukin-5 (IL-5) mRNA(+) cells (P = 0·03) and no change in interferon-γ (IFN-γ) mRNA(+) cells (P = 0·2) in the nasal mucosa. In contrast, in the immunotherapy-treated group, there were no changes in the number of CD3(+) T cells (P = 0·3) and IL-5 mRNA(+) cells (P = 0·2) but a significant increase in the number of IFN-γ mRNA(+) cells (P = 0·03). Furthermore, clinical improvement in the immunotherapy-treated group was accompanied by a seasonal increase in the ratio of IFN-γ to IL-5 mRNA(+) cells in the nasal mucosa (P = 0·03). In contrast, there were no significant changes in peripheral T-cell proliferative responses or cytokine production for IFN-γ or IL-5 in response to grass pollen either within or between the two treatment groups. We conclude that successful grass pollen immunotherapy was associated with an increase in the ratio of IFN-γ to IL-5 mRNA(+) cells in the nasal mucosa, whereas these changes were not reflected by alterations in peripheral blood T-cell proliferative responses or cytokine production before/after treatment

The braincase of a specimen of Proterochampsa Reig (Archosauriformes: Proterochampsidae) from the Late Triassic of Argentina

The proterochampsids are a Triassic group of superficially crocodile-like forms belonging to the Archosauriformes. In the present contribution, we present new information regarding the braincase of the proterochampsid Proterochampsa Reig 1959, from the Ischigualasto Formation (Carnian) of Argentina, and discuss its phylogenetic considerations. Some unique neurocranial features of Proterochampsa are described, including: the prominence and thickness of the V-shaped ridge that surrounds the basisphenoidal fossa; the medially concave lateral arms of the same ridge; and the semilunar depression on the parabasisphenoid ventrolaterally exposed. Other features are only shared with likely unrelated archosauriforms, including: the great lateral development of the basipterygoid processes and caudal development of its distal end; an eight-shaped metotic foramen; laterally directed basipterygoid processes; and rostral boundary of the basisphenoidal recess V-shaped. Proterochampsa differs in many other aspects from the archosauriform Chanaresuchus, including: a proportionally shorter basioccipital basal tubera; cultriform process ovoid in cross-section; longitudinal sulcus dorsal to the basipterygoid process; deep basisphenoidal recess; and the absence of a prominent intertuberal plate. In many braincase features, Proterochampsa is more similar to archosaurs than to Euparkeria, erythrosuchids and Proterosuchus. They include a reduced semilunar depression. A ventral border of the basioccipital forming a wide convexity and a dorsoventrally thin paroccipital process likely represents a feature shared with Chanaresuchus, but not with Doswellia and other basal archosauriforms.Fil: Trotteyn, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan; ArgentinaFil: Haro, Jose Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones Paleobiológicas; Argentin