Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities

Strong metal–metal coupling in mixed-valent intermediates [Cl(L)Ru(μ-tppz)Ru(L)Cl]+, L = β-diketonato ligands, tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine

Five diruthenium(II) complexes [Cl(L)Ru(μ-tppz)Ru(L)Cl] (1–5) containing differently substituted β-diketonato derivatives (1: L = 2,4-pentanedionato; 2: L = 3,5-heptanedionato; 3: L = 2,2,6,6-tetramethyl-3,5-heptanedionato; 4: L = 3-methyl-2,4-pentanedionato; 5: L = 3-ethyl-2,4-pentanedionato) as ancillary ligands (L) were synthesized and studied by spectroelectrochemistry (UV-Vis- NIR, electron paramagnetic resonance (EPR)). X-ray structural characterisation revealed anti (1, 2, 5) or syn (3) configuration as well as non-planarity of the bis-tridentate tppz bridge and strong dπ(RuII) → π*(pyrazine, tppz) back- bonding. The widely separated one-electron oxidation steps, RuIIRuII/RuIIRuIII and RuIIRuIII/RuIIIRuIII, result in large comproportionation constants (Kc) of ≥1010 for the mixed-valent intermediates. The syn-configurated 3n exhibits a particularly high Kc of 1012 for n = 1+, accompanied by density functional theory (DFT)-calculated minimum Ru–N bond lengths for this RuIIRuIII intermediate. The electrogenerated mixed-valent states 1+–5+ exhibit anisotropic EPR spectra at 110 K with average values of 2.304–2.234 and g anisotropies Δg = g1–g3 of 0.82–0.99. Metal-to-metal charge transfer (MMCT) absorptions occur for 1+–5+ in the NIR region at 1660 nm–1750 nm (ε ≈ 2700 dm3 mol−1 cm−1, Δν1/2 ≈ 1800 cm−1). DFT calculations of 1+ and 3+ yield comparable Mulliken spin densities of about 0.60 for the metal ions, corresponding to valence-delocalised situations (Ru2.5)2. Rather large spin densities of about −0.4 were calculated for the tppz bridges in 1+ and 3+. The calculated electronic interaction values (VAB) for 1+–5+ are about 3000 cm−1, comparable to that for the Creutz–Taube ion at 3185 cm−1. The DFT calculations predict that the RuIIIRuIII forms in 12+–52+ prefer a triplet (S = 1) ground state with ΔE (S = 0 − S = 1) [similar]5000 cm−1. One-electron reduction takes place at the tppz bridge which results in species [Cl(L)RuII(μ-tppz˙−)RuII(L)Cl]− (1˙−–3˙−, 5˙−) which exhibit free radical-type EPR signals and NIR transitions typical of the tppz radical anion. The system 4n is distinguished by lability of the Ru–Cl bonds

A new Miocene whale-fall community dominated by the bathymodiolin mussel Adipicola from the Hobetsu area, Hokkaido, Japan

金沢大学理工研究域地球社会基盤学系We report the fourth record of a fossil whale-fall community in Japan. The new material consists of a single whale bone in association mainly with small bathymodiolin mussels, Adipicola sp., found in the Karumai Formation (late middle Miocene—early late Miocene) in the Hobetsu area of Hokkaido, Japan. This association of whale bone and Adipicola sp. and its mode of occurrence resembles the description of some other ancient whale-fall communities dominated by small mussels from the Olympic Peninsula in Washington State (early Oligocene), Shosanbetsu in Hokkaido (early middle Miocene) and Carpineti in northern Italy (middle Miocene) and constitutes an example of a chemosynthesis-based community sustained by whale-fall decay in the Miocene deep sea. The new example extends the Miocene distribution of bathymodiolin-dominated whale-fall communities to the northwestern Pacific Ocean

Discovery of chemosynthesis-based association on the Cretaceous basal leatherback sea turtle from Japan

金沢大学国際基幹教育院 GS教育系We report a Late Cretaceous chemosynthetic community fueled by decomposing basal leatherback sea turtle on the ocean floor in the western Pacific. The fossil association representing this community has been recovered from the matrix of a concretion containing a single carapace of Mesodermochelys sp. from Late Cretaceous outer shelf to upper slope deposit of northern Hokkaido, Japan. The carapace displays boreholes most likely performed by boring bivalves, and is associated with molluscan shells, mainly Provanna cf. nakagawensis and Thyasira tanabei. Since this association is similar to fauna already known from Late Cretaceous hydrocarbon seeps, sunken wood, and plesiosaur-falls in Hokkaido, it is suggested that all types of chemosynthesis-based communities in the Late Cretaceous of western Pacific may have belonged to the same regional pool of animals and were not yet fully differentiated into three independent types of communities as it is known today. This finding also indicates that the sulfophilic stage of the vertebrate-fall communities was supported not only by plesiosaur carcasses, which were previously reported, but also by sea turtle carcasses. It highlights the possibility of surviving vertebrate-fall communities through the end-Cretaceous mass extinction event on carcasses of sea turtles which are the only large marine vertebrates surviving this event. Copyright © 2017 R.G. Jenkins et al

Paleocene methane seep and wood-fall marine environments from Spitsbergen, Svalbard

A recently discovered Paleocene seep locality from Fossildalen on Spitsbergen, Svalbard, is described. This is one of a very few seep communities of the latest Cretaceous–earliest Palaeogene age, and the best preserved Paleocene seep community known so far. The seep carbonates and associated fossils have been first identified in museum collections, and subsequently sampled in the field. The carbonates are exclusively ex-situ and come from the offshore siltstones of the Basilika Formation. Isotopically light composition (δ13C values approaching -50‰ V-PDB), and characteristic petrographic textures of the carbonates combined with the isotopically light archaeal lipid are consistent with the formation at fossil hydrocarbon seep. The invertebrate fauna associated with the carbonates is of moderate diversity (16 species) and has a shallow water affinity. It contains a species of the thyasirid genus Conchocele, common in other seeps of that age. The finding sheds new light onto the history of seepage on Svalbard, and onto the evolution and ecology of seep faunas during the latest Cretaceous–earliest Palaeogene time interval

Longitudinal functional connectivity changes related to dopaminergic decline in Parkinson’s disease

Background: Resting-state functional magnetic resonance imaging (fMRI) studies have demonstrated that basal ganglia functional connectivity is altered in Parkinson’s disease (PD) as compared to healthy controls. However, such functional connectivity alterations have not been related to the dopaminergic deficits that occurs in PD over time. Objectives: To examine whether functional connectivity impairments are correlated with dopaminergic deficits across basal ganglia subdivisions in patients with PD both cross-sectionally and longitudinally. Methods: We assessed resting-state functional connectivity of basal ganglia subdivisions and dopamine transporter density using 11C-PE2I PET in thirty-four PD patients at baseline. Of these, twenty PD patients were rescanned after 19.9 ± 3.8 months. A seed-based approach was used to analyze resting-state fMRI data. 11CPE2I binding potential (BPND) was calculated for each participant. PD patients were assessed for disease severity. Results: At baseline, PD patients with greater dopaminergic deficits, as measured with 11C-PE2I PET, showed larger decreases in posterior putamen functional connectivity with the midbrain and pallidum. Reduced functional connectivity of the posterior putamen with the thalamus, midbrain, supplementary motor area and sensorimotor cortex over time were significantly associated with changes in DAT density over the same period. Furthermore, increased motor disability was associated with lower intraregional functional connectivity of the posterior putamen. Conclusions: Our findings suggest that basal ganglia functional connectivity is related to integrity of dopaminergic system in patients with PD. Application of resting-state fMRI in a large cohort and longitudinal scanning may be a powerful tool for assessing underlying PD pathology and its progression

A new Late Pliocene large provannid gastropod associated with hydrothermal venting at Kane Megamullion, Mid-Atlantic Ridge

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Taylor & Francis for personal use, not for redistribution. The definitive version was published in Journal of Systematic Palaeontology 10 (2012): 423-433, doi:10.1080/14772019.2011.607193.A new gastropod, Kaneconcha knorri gen et sp. nov., was found in marlstone dredged from the surface of Adam Dome at Kane Megamullion on the flank of the Mid-Atlantic Ridge in an area of former hydrothermal activity. The snail is interpreted as a large provannid similar to the chemosymbiotic genera Ifremeria and Alviniconcha. This is the first record of presumably chemosymbiotic provannids from the Atlantic Ocean and also the first fossil record of such large provannids associated with hydrothermal venting. Extant Alviniconcha and Ifremeria are endemic to hydrothermal vents in the Pacific and Indian oceans. Kaneconcha differs from Ifremeria in having no umbilicus and a posterior notch, and it differs from Alviniconcha in having the profile of the whorl slightly flattened and having no callus on the inner lip. A dark layer covering the Kaneconcha shell is interpreted here as a fossilized periostracum. The shell/periostracum interface shows fungal traces attributed to the ichnospecies Saccomorpha clava. We hypothesize that large chemosymbiotic provannids (i.e., Kaneconcha, Ifremeria, and Alviniconcha) form a clade that possibly diverged from remaining provannids in the Late Jurassic, with the Late Jurassic/Early Cretaceous Paskentana being an early member.R/V Knorr Cruise 180- 2 to Kane Megamullion was supported by National Science Foundation grant OCE- 0118445. A. Kaim acknowledges support from the Alexander von Humboldt Foundation. B. Tucholke acknowledges support from an Andrew W. Mellon Foundation Award for Innovative Research and from the Deep Ocean Exploration Institute at Woods Hole Oceanographic Institution

Contact Force and Scanning Velocity during Active Roughness Perception

Haptic perception is bidirectionally related to exploratory movements, which means that exploration influences perception, but perception also influences exploration. We can optimize or change exploratory movements according to the perception and/or the task, consciously or unconsciously. This paper presents a psychophysical experiment on active roughness perception to investigate movement changes as the haptic task changes. Exerted normal force and scanning velocity are measured in different perceptual tasks (discrimination or identification) using rough and smooth stimuli. The results show that humans use a greater variation in contact force for the smooth stimuli than for the rough stimuli. Moreover, they use higher scanning velocities and shorter break times between stimuli in the discrimination task than in the identification task. Thus, in roughness perception humans spontaneously use different strategies that seem effective for the perceptual task and the stimuli. A control task, in which the participants just explore the stimuli without any perceptual objective, shows that humans use a smaller contact force and a lower scanning velocity for the rough stimuli than for the smooth stimuli. Possibly, these strategies are related to aversiveness while exploring stimuli