Silurian (Ludlow) acastid trilobites from Gotland and Scania,Sweden

Acastid trilobites from Ludlow strata on Gotland include three stratigraphically non-overlapping species ofAcastella Reed:Acastella madidipes n. sp. (Hemse Marl and Eke Beds),A. breviceps (Angelin 1851) (Burgsvik Beds), andA. amatrix n. sp. (Hamra Beds, and probably Burgsvik Beds). Type and other material ofA. breviceps (Angelin) from the Klinta Formation, Scania, is revised. Meraspid and early holaspid material ofAcastella is described. Some characters supportAcaste and allied taxa of mostly Wenlock age as a monophyletic subfamily Acastinae.Acastella as widely recognized is a grade with Devonian species more closely related to Asteropyginae than to the Ludlow type species. Baltic Ludlow-P?00ED;dolí species previously placed inScotiella Delo form a distinct group,Ewacaste n. gen., that includes a species from the uppermost Eke Beds on Gotland.     

Evolution of blindness in scolopendromorph centipedes (Chilopoda: Scolopendromorpha): insight from an expanded sampling of molecular data

Relative to its diversity (34 genera, 700 species), Scolopendromorpha has been undersampled in molecular phylogenetic analyses compared with the other chilopod orders. Previous analyses based on morphology have not resolved several key controversies in systematics and evolutionary morphology unambiguously. Here we apply new molecular and morphological data to scolopendromorph phylogenetics, with a focus on the evolution of blindness. The taxonomic sample includes 19 genera, many lacking previous molecular data, and diverse, cosmopolitan genera of Scolopendridae are sampled by multiple species. Phylogenetic analysis with Direct Optimization used 94 morphological characters and ca. 4.5 kb of sequence data from two nuclear (18S and 28S rRNA) and two mitochondrial (16S rRNA and COI) loci. A single most‐parsimonious cladogram selected after sensitivity analyses resolves Scolopendromorpha as monophyletic, and divides it into a blind clade of three families (Plutoniumidae, Cryptopidae, Scolopocryptopidae) and its ocellate sister group, Scolopendridae. Some species‐rich, cosmopolitan genera (Cormocephalus, Otostigmus, Scolopendra) in Scolopendridae are non‐monophyletic, and in several instances (e.g. New and Old World Scolopendra) relationships are more congruent with geographical distributions than with traditional classifications. The tribe Asanadini is particularly subject to parameter‐sensitivity, nesting in the combined analysis within Scolopendrini but as sister to all other Scolopendrinae for molecular data alone. The total‐evidence tree unambiguously optimizes trunk segmentation: a 23‐segmented trunk has a single origin in the blind clade. © The Willi Hennig Society 2011.     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

Unveiling biases in soft‐tissue phosphatization: extensive preservation of musculature in the Cretaceous (Cenomanian) polychaete Rollinschaeta myoplena (Annelida: Amphinomidae)

The process of soft‐tissue phosphatization (the replication of labile tissues by calcium phosphate) is responsible for many instances of high‐resolution soft tissue preservation, often revealing anatomical insights into the animals that so preserved. However, while much work has gone into exploring key issues such as biases and micro‐controls, phosphatization remains poorly understood as a taphonomic process. Here, using camera lucida, plain‐light microscopy and SEM imagery, we address this issue by describing the taphonomy and fidelity of the musculature of Rollinschaeta myoplena Parry et al., a phosphatized annelid from the Cretaceous Konservat‐Lagerstätten of Hakel and Hjoula, Lebanon, with an unprecedented quantity of three‐dimensional soft‐tissue preservation. Analysis highlights two strong, previously recognized biases affecting the process of phosphatization: (1) a taxonomic bias restricted to R. myoplena that triggers unusually extensive phosphatization; and (2) a tissue bias whereby longitudinal and parapodial musculature show markedly higher fidelity in comparison to the musculature of the intestine and body wall circular muscles. Potential explanations for these biases include internal phosphate‐enrichment by relative muscle density, the relative rate of decay and the physiology of musculature. Incongruence between experimental decay series for polychaetes and the prevalence of labile tissue preservation over recalcitrant tissues in R. myoplena exposes the limits of decay experiments for understanding exceptional preservation.     

Palaeomorphology: fossils and the inference of cladistic relationships

Edgecombe, G.D. 2010. Palaeomorphology: fossils and the inference of cladistic relationships. —Acta Zoologica (Stockholm) 91 : 72–80 Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson’s bold conjecture that this phenomenon ‘may be non‐existent’. Suppositions and misconceptions about missing data, often couched in terms of ‘wildcard taxa’ and ‘the missing data problem’, continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no a priori (or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible.     

Phylogenetics of scutigeromorph centipedes (Myriapoda: Chilopoda) with implications for species delimitation and historical biogeography of the Australian and New Caledonian faunas

Phylogeny of the centipede order Scutigeromorpha has received recent attention from combined analyses of molecular and morphological data. Denser generic sampling, an additional marker (12S rRNA), and multiple specimens for selected species are used to explore phylogeny, biogeography and taxonomy of this charismatic group of centipedes. Among 55 specimens/27 species analysed for six genes are the first molecular data for the genera Dendrothereua , Pilbarascutigera , and Tachythereua , and previously unsampled species of Scutigerinae from Madagascar. Sampling density is especially increased for Thereuoneminae from Australia and New Caledonia. At the base of Scutigeromorpha, the split of Pselliodidae from Scutigerinidae + Scutigeridae is favoured by the optimal parameter set in combined analyses, but most suboptimal parameter sets instead unite pselliodids and scutigerinids. Dendrothereua is re-established for a Neotropical clade that variably resolves as sister to Tachythereua or separate from Scutigerinae, grouped with Pselliodidae and Scutigerinidae. As traditionally diagnosed, the genera that comprise most of Australian and New Caledonian diversity, Allothereua and Parascutigera , are mutually polyphyletic, though they unite as a well supported clade, sister to or including the Western Australian Pilbarascutigera . The main biogeographical signal within the Allothereua / Parascutigera clade is Western Australia as sister area to eastern Australia/New Caledonia, within which New Caledonian " Parascutigera " has a single origin under optimal parameter sets. Genetic variation within scutigeromorph species is appraised using samples of Scutigera coleoptrata throughout its native distribution plus presumed synanthropic records, and from the Allothereua/Parascutigera clade. Variation between six alleged narrow-range endemic species of Parascutigera in north Queensland is consistent with a single species.     

Anaerobic degradation of papermill sludge in a two-phase digester containing rumen microorganisms and colonized polyurethane foam

Summary The use of reticulated polyurethane foam as a support material for the immobilization of methanogenic associations and its application to the anaerobic treatment of fine particulate solid wastes was investigated. The colonization of polyurethane support particles in a continuous upflow reactor fed on a mixture of acetate, propionate and butyrate, was both rapid and dense. The combination of rumen microorganisms and colonized support particles in a two-phase digester resulted in an efficient anaerobic decomposition of papermill sludge.     

Soft‐Bodied Fossils Are Not Simply Rotten Carcasses – Toward a Holistic Understanding of Exceptional Fossil Preservation

Exceptionally preserved fossils are the product of complex interplays of biological and geological processes including burial, autolysis and microbial decay, authigenic mineralization, diagenesis, metamorphism, and finally weathering and exhumation. Determining which tissues are preserved and how biases affect their preservation pathways is important for interpreting fossils in phylogenetic, ecological, and evolutionary frameworks. Although laboratory decay experiments reveal important aspects of fossilization, applying the results directly to the interpretation of exceptionally preserved fossils may overlook the impact of other key processes that remove or preserve morphological information. Investigations of fossils preserving non‐biomineralized tissues suggest that certain structures that are decay resistant (e.g., the notochord) are rarely preserved (even where carbonaceous components survive), and decay‐prone structures (e.g., nervous systems) can fossilize, albeit rarely. As we review here, decay resistance is an imperfect indicator of fossilization potential, and a suite of biological and geological processes account for the features preserved in exceptional fossils.     

A timeline for terrestrialization: consequences for the carbon cycle in the Palaeozoic

The geochemical carbon cycle is strongly influenced by life on land, principally through the effects of carbon sequestration and the weathering of calcium and magnesium silicates in surface rocks and soils. Knowing the time of origin of land plants and animals and also of key organ systems (e.g. plant vasculature, roots, wood) is crucial to understand the development of the carbon cycle and its effects on other Earth systems. Here, we compare evidence from fossils with calibrated molecular phylogenetic trees (timetrees) of living plants and arthropods. We show that different perspectives conflict in terms of the relative timing of events, the organisms involved and the pattern of diversification of various groups. Focusing on the fossil record, we highlight a number of key biases that underpin some of these conflicts, the most pervasive and far-reaching being the extent and nature of major facies changes in the rock record. These effects probably mask an earlier origin of life on land than is evident from certain classes of fossil data. If correct, this would have major implications in understanding the carbon cycle during the Early Palaeozoic.