Dietary composition and prey preference of a new carnivorous marsupial species, the buff-footed antechinus (Antechinus mysticus), at the northern and southern limits of its range

The buff-footed antechinus (Antechinus mysticus) is a newly described carnivorous marsupial from eastern Australia. We examined the diet composition and prey preference of this little known dasyurid in the southernmost (Brisbane) and northernmost (Eungella) populations. Animals were captured over three months (July–September) during 2014 encompassing the breeding period (late July and August) of the species. Seasonal sampling carried over into a second year which followed the succeeding cohort of juveniles as they dispersed from their maternal nest (summer), through their maturation (autumn), to the beginning of breeding (winter), sampling across one complete generation. The diet of A. mysticus consisted predominantly of invertebrates, with 16 prey orders identified (11 Insecta, two Arachnida, two Myriapoda, one Crustacea). Vertebrate (Family Scincidae) consumption was recorded in low abundance at both sites. The diet of A. mysticus was dominated by Araneae (spiders), Blattodea (cockroaches) and Coleoptera (beetles). Comparison of identified prey consumption in scats with prey availability in pitfall traps showed A. mysticus to be a dietary generalist, opportunistically consuming mostly invertebrate prey with supplementary predation on small vertebrates. Juvenile A. mysticus preyed predominantly on Blattodea (33.4% mean percentage volume) and Coleoptera (31.6% mean percentage volume), potentially suggesting a preference for larger, easier to catch, prey items. Further exploration into the relationship between prey and body size is required to determine this.

Comparison of the Frequency of Sudden Cardiovascular Deaths in Young Competitive Athletes Versus Nonathletes: Should We Really Screen Only Athletes?

The issue of sudden death in young athletes and consideration for the most practical and optimal strategy to identify those genetic and/or congenital heart diseases responsible for these tragic events continues to be debated. However, proponents of broad-based and mandatory national preparticipation screening, including with 12-lead electrocardiograms have confined the focus to a relatively small segment of the youthful population who choose to engage in competitive athletic programs at the high school, college, and elite-professional level. Therefore, lost in this discussion of preparticipation screening of athletes is that the larger population of young people not involved in competitive sports (and, therefore, a priori are excluded from systematic screening) who nevertheless may die suddenly of the same cardiovascular diseases as athletes. To substantiate this hypothesis, we accessed the forensic Hennepin County, Minnesota registry in which cardiovascular sudden deaths were 8-fold more common in nonathletes (n = 24) than athletes (n = 3) and threefold more frequent in terms of incidence. The most common diseases responsible for sudden death were hypertrophic cardiomyopathy (n = 6) and arrhythmogenic right ventricular cardiomyopathy (n = 4). These data raise ethical considerations inherent in limiting systematic screening for unsuspected genetic and/or congenital heart disease to competitive athletes.

Benefits of being a generalist carnivore when threatened by climate change: the comparative dietary ecology of two sympatric semelparous marsupials, including a new endangered species (Antechinus arktos)

The endangered black-tailed dusky antechinus (Antechinus arktos) was described in 2014, so most aspects of its ecology are unknown. We examined diet composition and prey selection of A. arktos and a sympatric congener, the northern form of A. stuartii, at two sites in Springbrook National Park. Overall, taxa from 25 invertebrate orders were identified in the diets from 252 scat samples. Dietary components were similar for each species, but A. arktos consumed a higher frequency and volume of dipteran larvae and Diplopoda, while A. stuartii consumed more Coleoptera, Lepidoptera, Orthoptera and Isopoda. Both species of Antechinus had a higher percentage of ‘empty’ scats (devoid of any identifiable invertebrate material) in 2014 compared with 2015. The former was a drier year overall. Lower rainfall may have reduced abundance and diversity of arthropod prey, causing both species to supplement their diet with soft-bodied prey items such as earthworms, which are rarely detected in scats. Comparison of prey in scats with invertebrate captures from pitfall traps showed both species to be dietary generalists, despite exhibiting distinct preference and avoidance of certain prey categories. The ability of an endangered generalist marsupial to switch prey may be particularly advantageous considering the anticipated effects of climate change on Gondwanan rainforests during the mid-late 21st century.

The Perfect Murder: How a Suicide Became a Homicide

This case report describes the death of a 51-year-old female, which presented by autopsy, scene circumstances, and social history as a suicidal ligature hanging. However, when her boyfriend walked into a police department in another state, months later, claiming to have killed the woman and staged a hanging, the medical examiner's office was asked to review the admission, as it was thought wholly inconsistent with the timeline provided. Upon reenactment of the admission, the perpetrator perfectly demonstrated the use of a lateral vascular neck restraint (carotid restraint), known to incapacitate and potentially kill an individual within a matter of seconds. The autopsy finding of severe atherosclerotic heart disease was important in understanding the mechanism of death, the timeline of events, and in corroborating the confession. This case demonstrates the value of performing an autopsy even though investigation and history suggested an obvious cause and manner of death.

Suicide by Hypothermia: A Report of Two Cases and 23-Year Retrospective Review

Hypothermia deaths are frequently accidental and associated with impairment by alcohol, injuries, mental illness, or natural disease. Hypothermia as a method of suicide is unusual, with only nine case reports in the scientific literature. In the early months of 2014, during one of the coldest winters on record, the Hennepin County Medical Examiner's office investigated and certified two unrelated cases of suicide by hypothermia; we describe the salient features of these cases. A retrospective review of all cases investigated by our office from January 1991-April 2014 identified 146 cases in which “hypothermia” or “environmental cold exposure” was listed as a cause of death, contributing condition, or mechanism of injury. Death investigation narratives and autopsy reports were reviewed to confirm hypothermia and evaluate for the presence or absence of characteristic hypothermia findings. In these cases the manner of death was certified as follows: 116 accident (79.4%), 15 undetermined (10.3%), 8 suicide (5.5%), 6 natural (4.1%), and 1 homicide (0.7%). Further examination of the eight suicide cases revealed that half were female and half were male, and most were younger individuals with only one decedent above 50 years of age. Four of these deaths were associated with drug toxicities, five were associated with additional self-inflicted injuries (blunt force, sharp force, and/or gunshot wounds), and none of them exhibited paradoxical undressing. It is important for medicolegal death investigation professionals to recognize that, while rare, hypothermia deaths may represent intentional injury, and suicide as a manner of death should be considered in all cases.

Cerebral Toxoplasmosis Presenting as a Medical Examiner Case

Toxoplasma gondii is a common parasite, with infection rates ranging from 16–40% of the United States population to up to 80% in some Central and South American and European countries. Clinically significant toxoplasmosis is considerably rarer, primarily affecting those with compromised immune systems. In the era of widespread human immunodeficiency virus (HIV) testing and effective HIV therapies, toxoplasmosis is rarely encountered in the medical examiner setting. We report a case of previously undiagnosed cerebral toxoplasmosis in a prisoner not known to be HIV-positive, who was hospitalized and treated for a presumed head injury. Manifestations of toxoplasmosis, pathology, treatment, and outcomes are discussed. This case highlights the need for thorough autopsies not only for deaths apparently resulting from injuries in jails and correctional institutions, but also when prisoners are hospitalized for seemingly benign reasons, yet the cause of death remains unclear despite clinical evaluation and treatment.

Establishing a Multidisciplinary Network for the Workup of Sudden Cardiac Death

Sudden cardiac death (SCD) often falls under the jurisdiction of the medical examiner (ME). A recent expert consensus statement recommends cardiac evaluation for all first degree blood relatives of an individual with SCD and supports the referral of these family members to a multidisciplinary inherited arrhythmia clinic; however, most MEs lack the appropriate clinical network for a specific referral and family members are often not followed up. In 2010, Minnesota MEs and cardiovascular pathologists began collaborating with a cardiology referral center specializing in familial cardiac conditions to form a regional Sudden Death Network (SDN). The cardiac pathologists and MEs have established protocols for appropriate specimen retention in accordance with the National Association of Medical Examiners position paper on postmortem deoxyribonucleic acid (DNA) collection and for referring families for clinical evaluation. The expertise of a genetic counselor has been essential to the evaluation of these families in coordinating appropriate genetic testing and assisting with the identification of at-risk family members in extended pedigrees. This SDN uses a multidisciplinary approach for referral of family members for screening and treatment of SCD risk and represents an important resource for MEs. Development of SDNs across the country would lead to a more uniform approach to SCD follow-up and a more efficient use of clinical resources. The ME's role is essential in consulting cardiac pathologists when needed, establishing the correct diagnosis, collecting and retaining appropriate specimens, and initiating the referral of at-risk family members to specialists.

Prey of the silver-headed antechinus (Antechinus argentus), a new species of Australian dasyurid marsupial

The silver-headed antechinus (Antechinus argentus) is one of Australia’s most recently described mammals, and the single known population at Kroombit Tops in south-east Queensland is threatened. Nothing is known of the species’ ecology, so during 2014 we collected faecal pellets each month (March–September) from a population at the type locality to gather baseline data on diet composition. A total of 38 faecal pellets were collected from 12 individuals (eight females, four males) and microscopic analysis of pellets identified seven invertebrate orders, with 70% combined mean composition of beetles (Coleoptera: 38%) and cockroaches (Blattodea: 32%). Other orders that featured as prey were ants, crickets/grasshoppers, butterflies/moths, spiders, and true bugs. Given that faecal pellets could only be collected from a single habitat type (Eucalyptus montivaga high-altitude open forest) and location, this is best described as a generalist insectivorous diet that is characteristic of other previously studied congeners.

Overview of the Organization of Scientific Area Committees

The National Institute of Standards and Technologies (NIST) has transformed the majority of the Scientific Working Groups (SWGs) into the Organization of Scientific Area Committees (OSAC). The OSAC has been created to foster the development of standards and guidelines for the practice of documenting evidence by methods that are technically sound and accepted by the consensus of forensic practitioners. The OSAC is composed of 33 committees arranged in a hierarchy. Potential standards begin in a Subcommittee and must work their way through approval by the Subcommittee, the Subcommittee's parent Scientific Area Committee (SAC), and finally the Forensic Science Standards Board (FSSB) before being adopted into the FSSB Registry of Approved Standards. NIST hopes to find existing standards with technical merit that were developed through a standards development process for adoption as national standards of practice. The OSAC provides forensic scientists the unprecedented opportunity of validating their own scientific practices within the framework of sound scientific practice.

Phase segregation of sulfonate groups in Nafion interface lamellae, quantified via neutron reflectometry fitting techniques for multi-layered structures

Neutron reflectometry analysis methods for under-determined, multi-layered structures are developed and used to determine the composition depth profile in cases where the structure is not known a priori. These methods, including statistical methods, sophisticated fitting routines, and coupling multiple data sets, are applied to hydrated and dehydrated Nafion nano-scaled films with thicknesses comparable to those found coating electrode particles in fuel cell catalyst layers. These results confirm the lamellar structure previously observed on hydrophilic substrates, and demonstrate that for hydrated films they can accurately be described as layers rich in both water and sulfonate groups alternating with water-poor layers containing an excess of fluorocarbon groups. The thickness of these layers increases slightly and the amplitude of the water volume fraction oscillation exponentially decreases away from the hydrophilic interface. For dehydrated films, the composition oscillations die out more rapidly. The Nafion-SiO2 substrate interface contains a partial monolayer of sulfonate groups bonded to the substrate and a large excess of water compared to that expected by the water-to-sulfonate ratio, λ, observed throughout the rest of the film. Films that were made thin enough to truncate this lamellar region showed a depth profile nearly identical to thicker films, indicating that there are no confinement or surface effects altering the structure. Comparing the SLD profile measured for films dried at 60 °C to modeled composition profiles derived by removing water from the hydrated lamellae suggests incomplete re-mixing of the polymer groups upon dehydration, indicated limited polymer mobility in these Nafion thin films.

Conservation genetics of the water mouse, Xeromys myoides Thomas, 1889

The water mouse, Xeromys myoides, is currently recognised as a vulnerable species in Australia, inhabiting a small number of distinct and isolated coastal regions of Queensland and the Northern Territory. An examination of the evolutionary history and contemporary influences shaping the genetic structure of this species is required to make informed conservation management decisions. Here, we report the first analysis undertaken on the phylogeography and population genetics of the water mouse across its mainland Australian distribution. Genetic diversity was assessed at two mitochondrial DNA (Cytochrome b, 1000 bp; D-loop, 400 bp) and eight microsatellite DNA loci. Very low genetic diversity was found, indicating that water mice underwent a recent expansion throughout their Australian range and constitute a single evolutionarily significant unit. Microsatellite analyses revealed that the highest genetic diversity was found in the Mackay region of central Queensland; population substructure was also identified, suggesting that local populations may be isolated in this region. Conversely, genetic diversity in the Coomera region of south-east Queensland was very low and the population in this region has experienced a significant genetic bottleneck. These results have significant implications for future management, particularly in terms of augmenting populations through translocations or reintroducing water mice in areas where they have gone extinct.

Taxonomy and redescription of the Atherton Antechinus, Antechinus godmani (Thomas) (Marsupialia: Dasyuridae)

We provide a taxonomic redescription of the dasyurid marsupial Atherton Antechinus, Antechinus godmani (Thomas). A. godmani is only rarely encountered and limited to wet tropical rainforests of north-east Queensland, Australia, between the towns of Cardwell and Cairns (a distribution spanning 135 kilometres from north to south). The distinctive species occurs at altitudes of over 600 meters asl, in all major rainforest types, and can be found with both the northern subspecies of the Yellow-footed Antechinus, A. flavipes rubeculus Van Dyck and the Rusty Antechinus, A. adustus (Thomas). A. godmani is clearly separated from all congeners on the basis of both morphometrics and genetics. A. godmani can be distinguished from all extant congeners based on external morphology by a combination of large size, naked-looking tail and reddish fur on the face and head. A. godmani skulls are characteristically large, with a suite of long features: basicranium, palate, upper premolar tooth row, inter-palatal vacuity distance and dentary. Phylogenies generated from mt- and nDNA data position Antechinus godmani as monophyletic with respect to other members of the genus; A. godmani is strongly supported as the sister-group to a clade containing all other antechinus, but excluding the south-east Australian Dusky Antechinus, A. swainsonii (Waterhouse) and Swamp Antechinus, A. minimus (Geoffroy). Antechinus godmani are genetically very divergent compared to all congeners (mtDNA: range 12.9-16.3%).

Unexpected Death from Hemorrhagic Pericarditis Complicating IgA Nephropathy

IgA nephropathy is the most common cause of glomerulonephritis in the developed world; however, it is usually an indolent or slowly progressive disease presenting initially as self-limited hematuria, typically following a viral or bacterial infection. We report a case of previously undiagnosed IgA nephropathy manifesting with end stage renal disease, fibrinous pericarditis, and hemorrhagic pericardial effusion in a 26-year-old white male. Clinical manifestations of IgA nephropathy, the presumed pathogenesis, and complications are reviewed. This case highlights the importance of interdisciplinary collaborations with other specialized pathology services—in this case renal pathology, including direct immunofluorescence and electron microscopy—that may not be routinely available or used in forensic pathology practices. In this instance, such collaboration provided the etiologically specific diagnosis for an unusual presentation of a common disease.

Molecular phylogeny supports the paraphyletic nature of the genus Trogoderma (Coleoptera: Dermestidae) collected in the Australasian ecozone

To date, a molecular phylogenetic approach has not been used to investigate the evolutionary structure of Trogoderma and closely related genera. Using two mitochondrial genes, Cytochrome Oxidase I and Cytochrome B, and the nuclear gene, 18S, the reported polyphyletic positioning of Trogoderma was examined. Paraphyly in Trogoderma was observed, with one Australian Trogoderma species reconciled as sister to all Dermestidae and the Anthrenocerus genus deeply nested within the Australian Trogoderma clade. In addition, time to most recent common ancestor for a number of Dermestidae was calculated. Based on these estimations, the Dermestidae origin exceeded 175 million years, placing the origins of this family in Pangaea.