Elemental signatures of Australopithecus africanus teeth reveal seasonal dietary stress.

Reconstructing the detailed dietary behaviour of extinct hominins is challenging1-particularly for a species such as Australopithecus africanus, which has a highly variable dental morphology that suggests a broad diet2,3. The dietary responses of extinct hominins to seasonal fluctuations in food availability are poorly understood, and nursing behaviours even less so; most of the direct information currently available has been obtained from high-resolution trace-element geochemical analysis of Homo sapiens (both modern and fossil), Homo neanderthalensis4 and living apes5. Here we apply high-resolution trace-element analysis to two A. africanus specimens from Sterkfontein Member 4 (South Africa), dated to 2.6-2.1 million years ago. Elemental signals indicate that A. africanus infants predominantly consumed breast milk for the first year after birth. A cyclical elemental pattern observed following the nursing sequence-comparable to the seasonal dietary signal that is seen in contemporary wild primates and other mammals-indicates irregular food availability. These results are supported by isotopic evidence for a geographical range that was dominated by nutritionally depauperate areas. Cyclical accumulation of lithium in A. africanus teeth also corroborates the idea that their range was characterized by fluctuating resources, and that they possessed physiological adaptations to this instability. This study provides insights into the dietary cycles and ecological behaviours of A. africanus in response to food availability, including the potential cyclical resurgence of milk intake during times of nutritional challenge (as observed in modern wild orangutans5). The geochemical findings for these teeth reinforce the unique place of A. africanus in the fossil record, and indicate dietary stress in specimens that date to shortly before the extinction of Australopithecus in South Africa about two million years ago.

Biomechanical correlates of zygomaxillary-surface shape in papionin primates and the effects of hard-object feeding on mangabey facial form.

Extant African papioninans are distinguished from macaques by the presence of excavated facial fossae; however, facial excavation differs among taxa. Mangabeys (Cercocebus, Rungwecebus, and Lophocebus) exhibit fossae that invade the zygomatic forming pronounced suborbital fossae (SOFs). Larger-bodied Papio, Mandrillus, and Theropithecus have lateral rostral fossae with minimal/absent suborbital fossae. Because prior studies have shown that mangabeys exhibit adaptations to anterior dental loading (e.g., palatal retraction), it is plausible that mangabey SOFs represent structural accommodation to masticatory-system shape rather than facial allometry, as commonly hypothesized. We analyzed covariation between zygomaxillary-surface shape, masticatory-system shape, and facial size in 141 adult crania of Macaca fascicularis, Papio kindae, Cercocebus, and Lophocebus. These taxa represent the range of papionin SOF expression while minimizing size variation (narrow allometry). Masticatory-system landmarks (39) registered palate shape, bite points, masticatory muscle attachments, and the temporomandibular joint. Semilandmarks (450) captured zygomaxillary-surface shape. Following Procrustes superimposition with semilandmark sliding and principal components analyses, multivariate regression was used to explore allometry, and two-block partial least-squares analyses (within-configuration and separate-blocks) were used to examine covariation patterns. Scores on principal components 1-2 and the first partial least-square (PLS1) separate mangabeys from Macaca and Papio. Both zygomaxillary-surface shape and masticatory-system shape are correlated with size within taxa and facial morphotypes; however, regression distributions indicate morphotype shape differences are non-allometric. PLS1 accounts for ∼95% of shape covariance (p < 0.0001) and shows strong linear correlations (r-PLS = âˆ¼0.95, p < 0.0001) between blocks. Negative PLS1 scores in mangabeys reflect deep excavation of the suborbital malar surface, palatal retraction, and anterior displacement of jaw adductor muscles and the temporomandibular joint. Neither PC1 nor PLS1 scores ordinate specimens by facial size. Taken together, these results fail to support the allometric hypothesis but suggest that mangabey zygomaxillary morphology is closely linked with adaptations to hard-object feeding.

A universal power law for modelling the growth and form of teeth, claws, horns, thorns, beaks, and shells.

BACKGROUND: A major goal of evolutionary developmental biology is to discover general models and mechanisms that create the phenotypes of organisms. However, universal models of such fundamental growth and form are rare, presumably due to the limited number of physical laws and biological processes that influence growth. One such model is the logarithmic spiral, which has been purported to explain the growth of biological structures such as teeth, claws, horns, and beaks. However, the logarithmic spiral only describes the path of the structure through space, and cannot generate these shapes. RESULTS: Here we show a new universal model based on a power law between the radius of the structure and its length, which generates a shape called a 'power cone'. We describe the underlying 'power cascade' model that explains the extreme diversity of tooth shapes in vertebrates, including humans, mammoths, sabre-toothed cats, tyrannosaurs and giant megalodon sharks. This model can be used to predict the age of mammals with ever-growing teeth, including elephants and rodents. We view this as the third general model of tooth development, along with the patterning cascade model for cusp number and spacing, and the inhibitory cascade model that predicts relative tooth size. Beyond the dentition, this new model also describes the growth of claws, horns, antlers and beaks of vertebrates, as well as the fangs and shells of invertebrates, and thorns and prickles of plants. CONCLUSIONS: The power cone is generated when the radial power growth rate is unequal to the length power growth rate. The power cascade model operates independently of the logarithmic spiral and is present throughout diverse biological systems. The power cascade provides a mechanistic basis for the generation of these pointed structures across the tree of life.

Low elbow mobility indicates unique forelimb posture and function in a giant extinct marsupial.

Joint mobility is a key factor in determining the functional capacity of tetrapod limbs, and is important in palaeobiological reconstructions of extinct animals. Recent advances have been made in quantifying osteological joint mobility using virtual computational methods; however, these approaches generally focus on the proximal limb joints and have seldom been applied to fossil mammals. Palorchestes azael is an enigmatic, extinct ~1000 kg marsupial with no close living relatives, whose functional ecology within Australian Pleistocene environments is poorly understood. Most intriguing is its flattened elbow morphology, which has long been assumed to indicate very low mobility at this important joint. Here, we tested elbow mobility via virtual range of motion (ROM) mapping and helical axis analysis, to quantitatively explore the limits of Palorchestes' elbow movement and compare this with their living and extinct relatives, as well as extant mammals that may represent functional analogues. We find that Palorchestes had the lowest elbow mobility among mammals sampled, even when afforded joint translations in addition to rotational degrees of freedom. This indicates that Palorchestes was limited to crouched forelimb postures, something highly unusual for mammals of this size. Coupled flexion and abduction created a skewed primary axis of movement at the elbow, suggesting an abducted forelimb posture and humeral rotation gait that is not found among marsupials and unlike that seen in any large mammals alive today. This work introduces new quantitative methods and demonstrates the utility of comparative ROM mapping approaches, highlighting that Palorchestes' forelimb function was unlike its contemporaneous relatives and appears to lack clear functional analogues among living mammals.

A Novel 3-Dimensional Printing Fabrication Approach for the Production of Pediatric Airway Models.

BACKGROUND: Pediatric airway models currently available for use in education or simulation do not replicate anatomy or tissue responses to procedures. Emphasis on mass production with sturdy but homogeneous materials and low-fidelity casting techniques diminishes these models' abilities to realistically represent the unique characteristics of the pediatric airway, particularly in the infant and younger age ranges. Newer fabrication technologies, including 3-dimensional (3D) printing and castable tissue-like silicones, open new approaches to the simulation of pediatric airways with greater anatomical fidelity and utility for procedure training. METHODS: After ethics approval, available/archived computerized tomography data sets of patients under the age of 2 years were reviewed to identify those suitable for designing new models. A single 21-month-old subject was selected for 3D reconstruction. Manual thresholding was then performed to produce 3D models of selected regions and tissue types within the dataset, which were either directly 3D-printed or later cast in 3D-printed molds with a variety of tissue-like silicones. A series of testing mannequins derived using this multimodal approach were then further refined following direct clinician feedback to develop a series of pediatric airway model prototypes. RESULTS: The initial prototype consisted of separate skeletal (skull, mandible, vertebrae) and soft-tissue (nasal mucosa, pharynx, larynx, gingivae, tongue, functional temporomandibular joint [TMJ] "sleeve," skin) modules. The first iterations of these modules were generated using both single-material and multimaterial 3D printing techniques to achieve the haptic properties of real human tissues. After direct clinical feedback, subsequent prototypes relied on a combination of 3D printing for osseous elements and casting of soft-tissue components from 3D-printed molds, which refined the haptic properties of the nasal, oropharyngeal, laryngeal, and airway tissues, and improved the range of movement required for airway management procedures. This approach of modification based on clinical feedback resulted in superior functional performance. CONCLUSIONS: Our hybrid manufacturing approach, merging 3D-printed components and 3D-printed molds for silicone casting, allows a more accurate representation of both the anatomy and functional characteristics of the pediatric airway for model production. Further, it allows for the direct translation of anatomy derived from real patient medical imaging into a functional airway management simulator, and our modular design allows for modification of individual elements to easily vary anatomical configurations, haptic qualities of components or exchange components to replicate pathology.

Design of a novel multifunction decision support/alerting system for in-patient acute care, ICU and floor (AlertWatch AC).

BACKGROUND: Multifunction surveillance alerting systems have been found to be beneficial for the operating room and labor and delivery. This paper describes a similar system developed for in-hospital acute care environments, AlertWatch Acute Care (AWAC). RESULTS: A decision support surveillance system has been developed which extracts comprehensive electronic health record (EHR) data including live data from physiologic monitors and ventilators and incorporates them into an integrated organ icon-based patient display. Live data retrieved from the hospitals network are processed by presenting scrolling median values to reduce artifacts. A total of 48 possible alerts are generated covering a broad range of critical patient care concerns. Notification is achieved by paging or texting the appropriated member of the critical care team. Alerts range from simple out of range values to more complex programing of impending Ventilator Associated Events, SOFA, qSOFA, SIRS scores and process of care reminders for the management of glucose and sepsis. As with similar systems developed for the operating room and labor and delivery, there are green, yellow, and red configurable ranges for all parameters. A census view allows surveillance of an entire unit with flashing or text to voice alerting and enables detailed information by windowing into an individual patient view including live physiologic waveforms. The system runs via web interface on desktop as well as mobile devices, with iOS native app available, for ease of communication from any location. The goal is to improve safety and adherence to standard management protocols. CONCLUSIONS: AWAC is designed to provide a high level surveillance view for multi-bed hospital units with varying acuity from standard floor patients to complex ICU care. Alerts are generated by algorithms running in the background and automatically notify the selected member of the patients care team. Its value has been demonstrated for low acuity patients, further study is required to determine its effectiveness in high acuity patients.

The reproduction of human pathology specimens using three-dimensional (3D) printing technology for teaching purposes.

The teaching of medical pathology has undergone significant change in the last 30-40 years, especially in the context of employing bottled specimens or 'pots' in classroom settings. The reduction in post-mortem based teaching in medical training programs has resulted in less focus being placed on the ability of students to describe the gross anatomical pathology of specimens. Financial considerations involved in employing staff to maintain bottled specimens, space constraints and concerns with health and safety of staff and student laboratories have meant that many institutions have decommissioned their pathology collections. This report details how full-colour surface scanning coupled with CT scanning and 3 D printing allows the digital archiving of gross pathological specimens and the production of reproductions or replicas of preserved human anatomical pathology specimens that obviates many of the above issues. With modern UV curable resin printing technology, it is possible to achieve photographic quality accurate replicas comparable to the original specimens in many aspects except haptic quality. Accurate 3 D reproductions of human pathology specimens offer many advantages over traditional bottled specimens including the capacity to generate multiple copies and their use in any educational setting giving access to a broader range of potential learners and users.

Did the thylacine violate the costs of carnivory? Body mass and sexual dimorphism of an iconic Australian marsupial.

The relative body masses of predators and their prey strongly affect the predators' ecology. An accurate estimate of the mass of an extinct predator is therefore key to revealing its biology and the structure of the ecosystem it inhabited. Until its extinction, the thylacine was the largest extant carnivorous marsupial, but little data exist regarding its body mass, with an average of 29.5 kg the most commonly used estimate. According to the costs of carnivory model, this estimate predicts that thylacines would have focused on prey subequal to or larger than themselves; however, many studies of their functional morphology suggest a diet of smaller animals. Here, we present new body mass estimates for 93 adult thylacines, including two taxidermy specimens and four complete mounted skeletons, representing 40 known-sex specimens, using three-dimensional volumetric model-informed regressions. We demonstrate that prior estimates substantially overestimated average adult thylacine body mass. We show mixed-sex population mean (16.7 kg), mean male (19.7 kg), and mean female (13.7 kg) body masses well below prior estimates, and below the 21 kg costs of carnivory threshold. Our data show that the thylacine did not violate the costs of carnivory. The thylacine instead occupied the 14.5-21 kg predator/prey range characterized by small-prey predators capable of occasionally switching to relatively large-bodied prey if necessary.

First monk seal from the Southern Hemisphere rewrites the evolutionary history of true seals.

Living true seals (phocids) are the most widely dispersed semi-aquatic marine mammals, and comprise geographically separate northern (phocine) and southern (monachine) groups. Both are thought to have evolved in the North Atlantic, with only two monachine lineages-elephant seals and lobodontins-subsequently crossing the equator. The third and most basal monachine tribe, the monk seals, have hitherto been interpreted as exclusively northern and (sub)tropical throughout their entire history. Here, we describe a new species of extinct monk seal from the Pliocene of New Zealand, the first of its kind from the Southern Hemisphere, based on one of the best-preserved and richest samples of seal fossils worldwide. This unanticipated discovery reveals that all three monachine tribes once coexisted south of the equator, and forces a profound revision of their evolutionary history: rather than primarily diversifying in the North Atlantic, monachines largely evolved in the Southern Hemisphere, and from this southern cradle later reinvaded the north. Our results suggest that true seals crossed the equator over eight times in their history. Overall, they more than double the age of the north-south dichotomy characterizing living true seals and confirms a surprisingly recent major change in southern phocid diversity.

Natural climate solutions.

Better stewardship of land is needed to achieve the Paris Climate Agreement goal of holding warming to below 2 °C; however, confusion persists about the specific set of land stewardship options available and their mitigation potential. To address this, we identify and quantify "natural climate solutions" (NCS): 20 conservation, restoration, and improved land management actions that increase carbon storage and/or avoid greenhouse gas emissions across global forests, wetlands, grasslands, and agricultural lands. We find that the maximum potential of NCS-when constrained by food security, fiber security, and biodiversity conservation-is 23.8 petagrams of CO2 equivalent (PgCO2e) y-1 (95% CI 20.3-37.4). This is ≥30% higher than prior estimates, which did not include the full range of options and safeguards considered here. About half of this maximum (11.3 PgCO2e y-1) represents cost-effective climate mitigation, assuming the social cost of CO2 pollution is ≥100 USD MgCO2e-1 by 2030. Natural climate solutions can provide 37% of cost-effective CO2 mitigation needed through 2030 for a >66% chance of holding warming to below 2 °C. One-third of this cost-effective NCS mitigation can be delivered at or below 10 USD MgCO2-1 Most NCS actions-if effectively implemented-also offer water filtration, flood buffering, soil health, biodiversity habitat, and enhanced climate resilience. Work remains to better constrain uncertainty of NCS mitigation estimates. Nevertheless, existing knowledge reported here provides a robust basis for immediate global action to improve ecosystem stewardship as a major solution to climate change.

We need both natural and energy solutions to stabilize our climate.

We respond to concerns raised by Baldocchi and Penuelas who question the potential for ecosystems to provide carbon sinks and storage, and conclude that we should focus on decarbonizing our energy systems. While we agree with many of their concerns, we arrive at a different conclusion: we need strong action to advance both clean energy solutions and natural climate solutions (NCS) if we are to stabilize warming well below 2°C. Cost-effective NCS can deliver 11.3 PgCO2 e yr-1 or ~30% of near-term climate mitigation needs through protection, improved management, and restoration of ecosystems, as we increase overall ambition.

Technical note: The use of 3D printing in dental anthropology collections.

OBJECTIVES: Rapid prototyping (RP) technology is becoming more affordable, faster, and is now capable of building models with a high resolution and accuracy. Due to technological limitations, 3D printing in biological anthropology has been mostly limited to museum displays and forensic reconstructions. In this study, we compared the accuracy of different 3D printers to establish whether RP can be used effectively to reproduce anthropological dental collections, potentially replacing access to oftentimes fragile and irreplaceable original material. METHODS: We digitized specimens from the Yuendumu collection of Australian Aboriginal dental casts using a high-resolution white-light scanning system and reproduced them using four different 3D printing technologies: stereolithography (SLA); fused deposition modeling (FDM); binder-jetting; and material-jetting. We compared the deviations between the original 3D surface models with 3D print scans using color maps generated from a 3D metric deviation analysis. RESULTS: The 3D printed models reproduced both the detail and discrete morphology of the scanned dental casts. The results of the metric deviation analysis demonstrate that all 3D print models were accurate, with only a few small areas of high deviations. The material-jetting and SLA printers were found to perform better than the other two printing machines. CONCLUSIONS: The quality of current commercial 3D printers has reached a good level of accuracy and detail reproduction. However, the costs and printing times limit its application to produce large sample numbers for use in most anthropological studies. Nonetheless, RP offers a viable option to preserve numerically constraint fragile skeletal and dental material in paleoanthropological collections.

Design of a Novel Multifunction Decision Support Display for Anesthesia Care: AlertWatch® OR.

BACKGROUND: This paper describes the design of a multifunction alerting display for intraoperative anesthetic care. The design was inspired by the multifunction primary flight display used in modern aviation. RESULTS: The display retrieves live data from multiple sources; the physiologic monitors, the anesthesia information management system, the laboratory values and comorbidities from patient's problem summary list, medical history or history & physical. This information is integrated into a display composed of readily identifiable icons of organ systems, which are color coded to signify normal range, marginal range, abnormal range (by green, yellow, red respectively) and orange outlines for comorbidities/risk factors. There are dozens of text alerts, which can be presented as black text (informational), red text (important information) and red scrolling text (highest importance information). The alerts are derived from current standards in the literature and some involve complex calculations being conducted in the background. CONCLUSIONS: The goal of such a system is to improve the quality and safety of anesthetic care by providing enhanced situational awareness in a fashion analogous to the "glass cockpit" and its primary flight display which has improved aviation safety.

The remarkable convergence of skull shape in crocodilians and toothed whales.

The striking resemblance of long-snouted aquatic mammals and reptiles has long been considered an example of morphological convergence, yet the true cause of this similarity remains untested. We addressed this deficit through three-dimensional morphometric analysis of the full diversity of crocodilian and toothed whale (Odontoceti) skull shapes. Our focus on biomechanically important aspects of shape allowed us to overcome difficulties involved in comparing mammals and reptiles, which have fundamental differences in the number and position of skull bones. We examined whether diet, habitat and prey size correlated with skull shape using phylogenetically informed statistical procedures. Crocodilians and toothed whales have a similar range of skull shapes, varying from extremely short and broad to extremely elongate. This spectrum of shapes represented more of the total variation in our dataset than between phylogenetic groups. The most elongate species (river dolphins and gharials) are extremely convergent in skull shape, clustering outside of the range of the other taxa. Our results suggest the remarkable convergence between long-snouted river dolphins and gharials is driven by diet rather than physical factors intrinsic to riverine environments. Despite diverging approximately 288 million years ago, crocodilians and odontocetes have evolved a remarkably similar morphological solution to feeding on similar prey.

The vertebrate heart: an evolutionary perspective.

Convergence is the tendency of independent species to evolve similarly when subjected to the same environmental conditions. The primitive blueprint for the circulatory system emerged around 700-600 Mya and exhibits diverse physiological adaptations across the radiations of vertebrates (Subphylum Vertebrata, Phylum Chordata). It has evolved from the early chordate circulatory system with a single layered tube in the tunicate (Subphylum Urchordata) or an amphioxus (Subphylum Cephalochordata), to a vertebrate circulatory system with a two-chambered heart made up of one atrium and one ventricle in gnathostome fish (Infraphylum Gnathostomata), to a system with a three-chambered heart made up of two atria which maybe partially divided or completely separated in amphibian tetrapods (Class Amphibia). Subsequent tetrapods, including crocodiles and alligators (Order Crocodylia, Subclass Crocodylomorpha, Class Reptilia), birds (Subclass Aves, Class Reptilia) and mammals (Class Mammalia) evolved a four-chambered heart. The structure and function of the circulatory system of each individual holds a vital role which benefits each species specifically. The special characteristics of the four-chamber mammalian heart are highlighted by the peculiar structure of the myocardial muscle.

Evergrowing incisors of diprotodont marsupials record age and life history.

OBJECTIVE: Tooth growth and wear are commonly used tools for determining the age of mammals. The most speciose order of marsupials, Diprotodontia, is characterised by a pair of procumbent incisors within the lower jaw. This study examines the growth and wear of these incisors to understand their relationship with age and sex. DESIGN: Measurements of mandibular incisor crown and root length were made for two sister species of macropodid (kangaroos and wallabies); Macropus giganteus and Macropus fuliginosus. Histological analysis examined patterns of dentine and cementum deposition within these teeth. Broader generalisability within Diprotodontia was tested using dentally reduced Tarsipes rostratus - a species disparate in body size and incisor function to the studied macropodids. RESULTS: In the macropodid sample it is demonstrated that the hypsodont nature of these incisors makes measurements of their growth (root length) and wear (crown length) accurate indicators of age and sex. Model fitting finds that root growth proceeds according to a logarithmic function across the lifespan, while crown wear follows a pattern of exponential reduction for both macropodid species. Histological results find that secondary dentine deposition and cementum layering are further indicators of age. Incisor measurements are shown to correlate with age in the sample of T. rostratus. CONCLUSIONS: The diprotodontian incisor is a useful tool for examining chronological age and sex, both morphologically and microstructurally. This finding has implications for population ecology, palaeontology and marsupial evolution.

First hominine remains from a ~1.0 million year old bone bed at Cornelia-Uitzoek, Free State Province, South Africa.

We report here on evidence of early Homo around 1.0 Ma (millions of years ago) in the central plains of southern Africa. The human material, a first upper molar, was discovered during the systematic excavation of a densely-packed bone bed in the basal part of the sedimentary sequence at the Cornelia-Uitzoek fossil vertebrate locality. We dated this sequence by palaeomagnetism and correlated the bone bed to the Jaramillo subchron, between 1.07 and 0.99 Ma. This makes the specimen the oldest southern African hominine remains outside the dolomitic karst landscapes of northern South Africa. Cornelia-Uitzoek is the type locality of the Cornelian Land Mammal Age. The fauna contains an archaic component, reflecting previous biogeographic links with East Africa, and a derived component, suggesting incipient southern endemism. The bone bed is considered to be the result of the bone collecting behaviour of a large predator, possibly spotted hyaenas. Acheulian artefacts are found in small numbers within the bone bed among the fossil vertebrates, reflecting the penecontemporaneous presence of people in the immediate vicinity of the occurrence. The hominine tooth was recovered from the central, deeper part of the bone bed. In size, it clusters with southern African early Homo and it is also morphologically similar. We propose that the early Homo specimen forms part of an archaic component in the fauna, in parallel with the other archaic faunal elements at Uitzoek. This supports an emergent pattern of archaic survivors in the southern landscape at this time, but also demonstrates the presence of early Homo in the central plains of southern Africa, beyond the dolomitic karst areas.