Suction feeding preceded filtering in baleen whale evolution

The origin of baleen, the key adaptation of modern whales (Mysticeti), marks a profound yet poorly understood transition in vertebrate evolution, triggering the rise of the largest animals on Earth. Baleen is thought to have appeared in archaic tooth-bearing mysticetes during a transitional phase that combined raptorial feeding with incipient bulk filtering. Here we show that tooth wear in a new Late Oligocene mysticete belonging to the putatively transitional family Aetiocetidae is inconsistent with the presence of baleen, and instead indicative of suction feeding. Our findings suggest that baleen arose much closer to the origin of toothless mysticete whales than previously thought. In addition, they suggest an entirely new evolutionary scenario in which the transition from raptorial to baleen-assisted filter feeding was mediated by suction, thereby avoiding the problem of functional interference between teeth and the baleen rack

Clawed forelimbs allow northern seals to eat like their ancient ancestors

Funding for this project was provided by a Marie Skłodowska-Curie Global Postdoctoral Fellowship (656010/MYSTICETI) to F.G.M, by Marine Scotland to support the wild observations recorded by R.N.H., by an Australian Research Council Future Fellowship FT130100968 to A.R.E., and by an Australian Research Council Linkage Project LP150100403 to A.R.E. and E.M.G.F.Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.Publisher PDFPeer reviewe

A global research priority agenda to advance public health responses to fatty liver disease

Background & aims An estimated 38% of adults worldwide have non-alcoholic fatty liver disease (NAFLD). From individual impacts to widespread public health and economic consequences, the implications of this disease are profound. This study aimed to develop an aligned, prioritised fatty liver disease research agenda for the global health community. Methods Nine co-chairs drafted initial research priorities, subsequently reviewed by 40 core authors and debated during a three-day in-person meeting. Following a Delphi methodology, over two rounds, a large panel (R1 n = 344, R2 n = 288) reviewed the priorities, via Qualtrics XM, indicating agreement using a four-point Likert-scale and providing written feedback. The core group revised the draft priorities between rounds. In R2, panellists also ranked the priorities within six domains: epidemiology, models of care, treatment and care, education and awareness, patient and community perspectives, and leadership and public health policy. Results The consensus-built fatty liver disease research agenda encompasses 28 priorities. The mean percentage of ‘agree’ responses increased from 78.3 in R1 to 81.1 in R2. Five priorities received unanimous combined agreement (‘agree’ + ‘somewhat agree’); the remaining 23 priorities had >90% combined agreement. While all but one of the priorities exhibited at least a super-majority of agreement (>66.7% ‘agree’), 13 priorities had 90% combined agreement. Conclusions Adopting this multidisciplinary consensus-built research priorities agenda can deliver a step-change in addressing fatty liver disease, mitigating against its individual and societal harms and proactively altering its natural history through prevention, identification, treatment, and care. This agenda should catalyse the global health community’s efforts to advance and accelerate responses to this widespread and fast-growing public health threat. Impact and implications An estimated 38% of adults and 13% of children and adolescents worldwide have fatty liver disease, making it the most prevalent liver disease in history. Despite substantial scientific progress in the past three decades, the burden continues to grow, with an urgent need to advance understanding of how to prevent, manage, and treat the disease. Through a global consensus process, a multidisciplinary group agreed on 28 research priorities covering a broad range of themes, from disease burden, treatment, and health system responses to awareness and policy. The findings have relevance for clinical and non-clinical researchers as well as funders working on fatty liver disease and non-communicable diseases more broadly, setting out a prioritised, ranked research agenda for turning the tide on this fast-growing public health threat

Detailed histopathologic characterization of the retinopathy, globe enlarged (rge) chick phenotype.

Contains fulltext : 47395.pdf (publisher's version ) (Open Access)PURPOSE: The purpose of this study was to characterize the morphological abnormalities in the retinas of chicks (Gallus gallus) suffering from the autosomal recessive disease, retinopathy, globe enlarged (rge/rge). METHODS: rge/rge affected and age matched control retinas were examined from hatch up to 730 days of age. Thickness of retinal layers at six retinal regions was measured from plastic embedded sections. Morphological features were examined on semi-thin sections by light microscopy and on ultra-thin sections by transmission electron microscopy. Immunohistochemistry was performed using a panel of several different antibodies. Additionally, comparative counting of rod outer segments, rows of cells in the inner nuclear layer, and ganglion cells per unit length was performed. RESULTS: The earliest changes observed in rge/rge retinas were disorganization of the outer plexiform layer and abnormal location of the endoplasmic reticulum of the photoreceptors. In rge/rge retinas, cone pedicles were larger, irregular in shape, and usually contained multivesicular bodies. In addition, synaptic ribbons of the cone pedicles and rod spherules in rge/rge retinas were less numerous compared to controls. Large glycogen deposits progressively accumulated in the perinuclear cytoplasm associated with the abnormally located endoplasmic reticuli in accessory cones and rods. Total retinal thickness progressively decreased with age in rge/rge birds. This was accompanied by a decrease in the number of cells in the inner nuclear layer and a decrease in the number of rod outer segments (OSs). Several changes were detected in the rge/rge retinas using immunohistochemistry, including mislocalized opsin immunoreactivity of rod photoreceptors, a decrease in number and disorganization of opsin positive rod OSs (especially in the peripheral regions), a decrease in number of tyrosine hydroxylase positive neurites in the distal inner plexiform layer, and activation of macroglial and microglial cells. CONCLUSIONS: As we previously reported, the rge/rge chick has vision loss that is not the result of photoreceptor loss and is unusual in that electroretinographic responses, although abnormal, are maintained until well after vision loss has developed. The phenotype is associated with a developmental disruption of both rod and cone photoreceptor synaptic terminals that progresses with age. It is possible that these changes may be indicative of abnormal circuitry within the outer plexiform layer, and that they underlie the progressive loss of vision in rge/rge birds. Other early changes suggesting photoreceptor abnormality are dilation of photoreceptor cell bodies, abnormal positioning of endoplasmic reticulum in the perinuclear region that is associated with abnormal glycogen deposition, and mislocalization of opsin immunoreactivity in rods. The rge/rge birds develop globe enlargement after the morphological and electroretinographic abnormalities. Globe enlargement in chicks can be induced by a number of different environmental factors. It is possible that abnormal signaling of photoreceptors to inner retinal cells could induce excessive ocular growth in the rge/rge birds. Many of the morphological changes such as retinal thinning seen in older rge/rge birds may be partly the result of the considerable globe enlargement that occurs later in the disease process. Molecular genetic studies to identify the causal gene mutation should help explain the morphological features of the rge/rge phenotype and clarify their association with vision loss and electroretinographic abnormalities