Whale falls produce remarkable organic- and sulfide-rich habitat islands at the seafloor. The past decade has seen a dramatic increase in studies of modern and fossil whale remains, yielding exciting new insights into whale-fall ecosystems. Giant body sizes and especially high bone-lipid content allow great-whale carcasses to support a sequence of heterotrophic and chemosynthetic microbial assemblages in the energy-poor deep sea. Deep-sea metazoan communities at whale falls pass through a series of overlapping successional stages that vary with carcass size, water depth, and environmental conditions. These metazoan communities contain many new species and evolutionary novelties, including bone-eating worms and snails and a diversity of grazers on sulfur bacteria. Molecular and paleoecological studies suggest that whale falls have served as hot spots of adaptive radiation for a specialized fauna; they have also provided evolutionary stepping stones for vent and seep mussels and could have facilitated speciation in other vent/seep taxa.

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Whale-Fall Ecosystems: Recent Insights into Ecology, Paleoecology, and Evolution

Post-mortem examination of dead and live stranded beach-cast pinnipeds and cetaceans for determination of a cause of death provides valuable information for the management, mitigation and prosecution of unintentional and sometimes malicious human impacts, such as vessel collision, fishing gear entanglement and gunshot. Delayed discovery, inaccessibility, logistics, human safety concerns, and weather make these events challenging. Over the past 3 decades, in response to public concern and federal and state or provincial regulations mandating such investigations to inform mitigation efforts, there has been an increasing effort to objectively and systematically investigate these strandings from a diagnostic and forensic perspective. This Theme Section provides basic investigative methods, and case definitions for each of the more commonly recognized case presentations of human interactions in pinnipeds and cetaceans. Wild animals are often adversely affected by factors such as parasitism, anthropogenic contaminants, biotoxins, subclinical microbial infections and competing habitat uses, such as prey depletion and elevated background and episodic noise. Understanding the potential contribution of these subclinical factors in predisposing or contributing to a particular case of trauma of human origin is hampered, especially where putrefaction is significant and resources as well as expertise are limited. These case criteria descriptions attempt to acknowledge those confounding factors to enable an appreciation of the significance of the observed human-derived trauma in that broader context where possible.

https://www.int-res.com/articles/dao_oa/d103p229.pdf

Criteria and case definitions for serious injury and death of pinnipeds and cetaceans caused by anthropogenic trauma.

Althoughcardiomyopathy is no longeran uncommon diagnosis the definition as heart muscle disease of unknown etiology still applies. This book, which appears to be based on a symposium, aims to present an up-to-date account of recent developments in this field. Most contributions relate to the primary forms; there are also papers on hypertrophy of other causes, experimental cardiomyopathy, tefhnical aspects and problems of myocardial biopsy techniques together with a large section on angiography and non-invasive diagnostic procedures. All but three of the 46 contributors are from Germany, and the editors are to be congratulated on the fact that this is in no way apparent in their texts. The papers are mainly short, clearly written, and well illustrated. The place of myocardial biopsy is still being debated, and the editors conclude that although the procedure may be useful for prognosis its main value is in research, and its general application is not justified. The book probably offers little of immediate relevance to most readers of this journal since the pathological emphasis is predictably on ultrastructure. However, those working in centres where myocardial biopsies are performed or under consideration will undoubtedly find it of interest. ARIELA POMERANCE

https://jcp.bmj.com/content/jclinpath/31/10/1006.3.full.pdf

Forensic Medicine: A Study in Trauma and Environmental Hazards.

Mortality from collisions with vessels is one of the main human causes of death for large whales. Ship strikes are rarely witnessed and the distribution of strike risk and estimates of mortality remain uncertain at best. We estimated ship strike mortality for blue humpback and fin whales in U.S. West Coast waters using a novel application of a naval encounter model. Mortality estimates from the model were far higher than current minimum estimates derived from stranding records and are closer to extrapolations adjusted for detection probabilities of dead whales. Our most conservative model estimated mortality to be 7.8x, 2.0x and 2.7x the U.S. recommended limit for blue, humpback and fin whales, respectively, suggesting that death from vessel collisions may be a significant impediment to population growth and recovery. Comparing across the study area, the majority of strike mortality occurs in waters off California, from Bodega Bay south and tends to be concentrated in a band approximately 24 Nm (44.5 km) offshore and in designated shipping lanes leading to and from major ports. While some mortality risk exists across nearly all West Coast waters, 74%, 82% and 65% of blue, humpback and fin whale mortality, respectively, occurs in just 10% of the study area, suggesting conservation efforts can be very effective if focused in these waters. Risk is highest in the shipping lanes off San Francisco and Long Beach, but only a fraction of total estimated mortality occurs in these proportionally small areas, making any conservation efforts exclusively within these areas insufficient to address overall strike mortality. We recommend combining shipping lane modifications and re-locations, ship speed reductions and creation of 'Areas to be Avoided' by vessels in ecologically important locations to address this significant source of whale mortality.

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High mortality of blue, humpback and fin whales from modeling of vessel collisions on the U.S. West Coast suggests population impacts and insufficient protection

More or less complete and articulated skeletons of fossil air-breathing vertebrates with a long neck and tail often exhibit a body posture in which the head and neck are recurved over the back of the animal. Additionally, the tail is typically drawn over the body, while the limbs have a rigid appearance. In palaeontological literature, this “opisthotonic posture” of such fossils still requires a causal interpretation in an etiological context. According to this hypothesis, there is a presumption of a cerebral disorder generating perimortem muscle spasms that are preserved by rapid burial or other sequestration of a skeleton in the fossil record. We re-evaluate this “opisthotonic posture hypothesis” by analysing the non-avian theropods Compsognathus longipes and Juravenator starki from the famous South Franconian plattenkalks of the Upper Jurassic Solnhofen Archipelago. Decay experiments with the extant domestic fowl Gallus gallus L. and analysis of the theropods’ constructional morphological constraints reveal that the opisthotonic posture is not a peri- but a postmortem phenomenon. By analysing the timeline of decomposition, it is possible to recognise different stages of decay, depending on the varying decay resistance of soft tissues. Adipocere formation must have blocked further decay until embedding was completed by minimal sedimentation. Analyses of the palaeoenvironment of the basins of the Solnhofen Archipelago show that the conditions of deposition of individual basins cannot be considered to be similar, even inside the same time frame. Therefore, a generalised approach of looking at the depositional setting must be excluded. Assumptions by Faux and Padian (2007) that the accepted palaeoenvironmental reconstruction of the Solnhofen Fossillagerstatte has to be questioned in the light of the opisthotonic posture hypothesis enforce the need for a review of palaeoecological factors of the Franconian Plattenkalks from a taphonomic perspective.

https://doc.rero.ch/record/314728/files/12549_2011_Article_68.pdf

Re-evaluating Moodie’s Opisthotonic-Posture Hypothesis in Fossil Vertebrates Part I: Reptiles—the taphonomy of the bipedal dinosaurs Compsognathus longipes and Juravenator starki from the Solnhofen Archipelago (Jurassic, Germany)

What happens after the death of a marine tetrapod in seawater? Palaeontologists and neontologists have claimed that large lung-breathing marine tetrapods such as ichthyosaurs had a lower density than seawater, implying that their carcasses floated at the surface after death and sank subsequently after leakage of putrefaction gases (or ‘‘carcass explosions’’). Such explosions would thus account for the skeletal disarticulation observed frequently in the fossil record. We examined the taphonomy and sedimentary environment of numerous ichthyosaur skeletons and compared them to living marine tetrapods, principally cetaceans, and measured abdominal pressures in human carcasses. Our data and a review of the literature demonstrate that carcasses sink and do not explode (and spread skeletal elements). We argue that the normally slightly negatively buoyant carcasses of ichthyosaurs would have sunk to the sea floor and risen to the surface only when they remained in shallow water above a certain temperature and at a low scavenging rate. Once surfaced, prolonged floating may have occurred and a carcass have decomposed gradually. Our conclusions are of significance to the understanding of the inclusion of carcasses of lung-breathing vertebrates in marine nutrient recycling. The postmortem fate has essential implications for the interpretation of vertebrate fossil preservation (the existence of complete, disarticulated fossil skeletons is not explained by previous hypotheses), palaeobathymetry, the physiology of modern marine lung-breathing tetrapods and their conservation, and the recovery of human bodies from seawater.

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Float, explode or sink: postmortem fate of lung-breathing marine vertebrates

In his recent discussion on the taphonomy of ichthyosaurs, van Loon (2013) supported—at least partially—the view of Reisdorf et al. (2012) and emphasized that explosion of vertebrate carcasses on the sea floor should not be considered as a taphonomically reasonable scenario. Carcass explosion is thus not a process that can be used to explain both the disarticulation of certain ichthyosaur skeletons and the displacement of their bones in the geological record. Van Loon (2013), however, did suggest that, as an alternative hypothesis, implosion could have led to the displacement of bones on the sea floor. Van Loon (2013) focussed his explanation of the implosion hypothesis on the example of a maternal ichthyosaur having embryonic ichthyosaurs around and within its body cavity (Staatliches Museum fur Naturkunde Stuttgart, specimen number SMNS 50 007). Reisdorf et al. (2012) outlined that

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Daniel Wyler

Papers

Float, explode or sink: postmortem fate of lung-breathing marine vertebrates

Reply to “Ichthyosaur embryos outside the mother body: not due to carcass explosion but to carcass implosion” by van Loon (2013)