Déjà vu: a reappraisal of the taphonomy of quarry VM4 of the Early Pleistocene site of Venta Micena (Baza Basin, SE Spain)

Venta Micena, an Early Pleistocene site of the Baza Basin (SE Spain), preserves a rich and diverse assemblage of large mammals. VM3, the main excavation quarry of the site, has been interpreted as a den of the giant hyaena Pachycrocuta brevirostris in the plain that surrounded the Baza palaeolake. Taphonomic analysis of VM3 has shown that the hyaenas scavenged the prey previously hunted by the hypercarnivores, transported their remains to the communal den, and consumed the skeletal parts according to their marrow contents and mineral density. In a recent paper (Luzón et al. in Sci Rep 11:13977, 10.1038/s41598-021-93261-1, 2021), a small sample of remains unearthed from VM4, an excavation quarry ~ 350 m distant from VM3, is analysed. The authors indicate several differences in the taphonomic features of this assemblage with VM3, and even suggest that a different carnivore could have been the agent involved in the bone accumulation process. Here, we make a comparative analysis of both quarries and analyse more skeletal remains from VM4. Our results indicate that the assemblages are broadly similar in composition, except for slight differences in the frequency of megaherbivores, carnivores and equids according to NISP values (but not to MNI counts), the degree of bone weathering, and the intensity of bone processing by the hyaenas. Given that VM4 and VM3 were not coeval denning areas of P. brevirostris, these differences suggest that during the years when the skeletal remains were accumulated by the hyaenas at VM3, the rise of the water table of the Baza palaeolake that capped with limestone the bones was delayed compared to VM4, which resulted in their more in-depth consumption by the hyaenas.

Déjà vu: A reappraisal of the taphonomy of quarry VM4 of the Early Pleistocene site of Venta Micena (Baza Basin, SE Spain)

Venta Micena, an Early Pleistocene site of the Baza Basin (SE Spain), preserves a rich and diverse assemblage of large mammals. VM3, the main excavation quarry of the site, has been interpreted as a den of the giant hyaena Pachycrocuta brevirostris in the plain that surrounded the Baza palaeolake. Taphonomic analysis of VM3 has shown that the hyaenas scavenged the prey previously hunted by the hypercarnivores, transported their remains to the communal den, and consumed the skeletal parts according to their marrow contents and mineral density. In a recent paper, a small sample of remains unearthed from VM4, an excavation quarry ~350 m distant from VM3, are analysed. The authors indicate several differences in the taphonomic features of this assemblage with VM3, and even suggest that a different carnivore could have been the agent involved in the bone accumulation process. Here we make a comparative analysis of both quarries and analyse more skeletal remains from VM4. Our results indicate that the assemblages are broadly similar in composition, except for slight differences in the frequency of megaherbivores, carnivores and equids according to NISP values (but not to MNI counts), the degree of bone weathering, and the intensity of bone processing by the hyaenas. Given that VM4 and VM3 were not coeval denning areas of P. brevirostris, these differences suggest that during the years when the skeletal remains were accumulated by the hyaenas at VM3, the rise of the water table of the Baza palaeolake that capped with limestone the bones was delayed compared to VM4, which resulted in their more in-depth consumption by the hyaenas.

Déjà vu: A reappraisal of the taphonomy of quarry VM4 of the Early Pleistocene site 1 of Venta Micena (Baza Basin, SE Spain"

Venta Micena, an Early Pleistocene site of the Baza Basin (SE Spain), preserves a rich and diverse assemblage of large mammals. VM3, the main excavation quarry of the site, has been interpreted as a den of the giant hyaena Pachycrocuta brevirostris in the plain that surrounded the Baza palaeolake. Taphonomic analysis of VM3 has shown that the hyaenas scavenged the prey previously hunted by the hypercarnivores, transported their remains to the communal den, and consumed the skeletal parts according to their marrow contents and mineral density. In a recent paper, a small sample of remains unearthed from VM4, an excavation quarry ~350 m distant from VM3, are analysed. The authors indicate several differences in the taphonomic features of this assemblage with VM3, and even suggest that a different carnivore could have been the agent involved in the bone accumulation process. Here we make a comparative analysis of both quarries and analyse more skeletal remains from VM4. Our results indicate that the assemblages are broadly similar in composition, except for slight differences in the frequency of megaherbivores, carnivores and equids according to NISP values (but not to MNI counts), the degree of bone weathering, and the intensity of bone processing by the hyaenas. Given that VM4 and VM3 were not coeval denning areas of P. brevirostris, these differences suggest that during the years when the skeletal remains were accumulated by the hyaenas at VM3, the rise of the water table of the Baza palaeolake that capped with limestone the bones was delayed compared to VM4, which resulted in their more in-depth consumption by the hyaenas.

Taphonomy of an excavated striped hyena (Hyaena hyaena) den in Arabia: implications for paleoecology and prehistory

Studies of modern carnivore accumulations of bone (i.e., neo-taphonomy) are crucial for interpreting fossil accumulations in the archaeological and paleontological records. Yet, studies in arid regions have been limited in both number and detailed taphonomic data, prohibiting our understanding of carnivore bone-accumulating and -modifying behavior in dry regions. Here, we present a taphonomic analysis of an impressive carnivore-accumulated bone assemblage from the Umm Jirsan lava tube in the Harrat Khaybar region, Saudi Arabia. The size and composition of the bone accumulation, as well as the presence of hyena skeletal remains and coprolites, suggest that the assemblage was primarily accumulated by striped hyena (Hyaena hyaena). Our findings (1) identify potentially useful criteria for distinguishing between accumulations generated by different species of hyenas; (2) emphasize the need for neo-taphonomic studies for capturing the full variation in carnivore bone-accumulating and modifying behavior; (3) suggest that under the right settings, striped hyena accumulations can serve as good proxies for (paleo)ecology and livestock practices; and (4) highlight the potential for future research at Umm Jirsan, as well as at the numerous nearby lava tube systems. We encourage continued neo-taphonomic efforts in regions important in human prehistory, particularly in arid zones, which have received little research attention.

Activin A promotes the development of acquired heterotopic ossification and is an effective target for disease attenuation in mice

Heterotopic ossification (HO) is a common, potentially debilitating pathology that is instigated by inflammation caused by tissue damage or other insults, which is followed by chondrogenesis, osteogenesis, and extraskeletal bone accumulation. Current remedies are not very effective and have side effects, including the risk of triggering additional HO. The TGF-β family member activin A is produced by activated macrophages and other inflammatory cells and stimulates the intracellular effectors SMAD2 and SMAD3 (SMAD2/3). Because HO starts with inflammation and because SMAD2/3 activation is chondrogenic, we tested whether activin A stimulated HO development. Using mouse models of acquired intramuscular and subdermal HO, we found that blockage of endogenous activin A by a systemically administered neutralizing antibody reduced HO development and bone accumulation. Single-cell RNA-seq analysis and developmental trajectories showed that the antibody treatment reduced the recruitment of Sox9+ skeletal progenitors, many of which also expressed the gene encoding activin A (Inhba), to HO sites. Gain-of-function assays showed that activin A enhanced the chondrogenic differentiation of progenitor cells through SMAD2/3 signaling, and inclusion of activin A in HO-inducing implants enhanced HO development in vivo. Together, our data reveal that activin A is a critical upstream signaling stimulator of acquired HO in mice and could represent an effective therapeutic target against forms of this pathology in patients.

Deep learning improves taphonomic resolution: high accuracy in differentiating tooth marks made by lions and jaguars

Taphonomists have long struggled with identifying carnivore agency in bone accumulation and modification. Now that several taphonomic techniques allow identifying carnivore modification of bones, a next step involves determining carnivore type. This is of utmost importance to determine which carnivores were preying on and competing with hominins and what types of interaction existed among them during prehistory. Computer vision techniques using deep architectures of convolutional neural networks (CNN) have enabled significantly higher resolution in the identification of bone surface modifications (BSM) than previous methods. Here, we apply these techniques to test the hypothesis that different carnivores create specific BSM that can enable their identification. To make differentiation more challenging, we selected two types of carnivores (lions and jaguars) that belong to the same mammal family and have similar dental morphology. We hypothesize that if two similar carnivores can be identified by the BSM they imprint on bones, then two more distinctive carnivores (e.g. hyenids and felids) should be more easily distinguished. The CNN method used here shows that tooth scores from both types of felids can be successfully classified with an accuracy greater than 82%. The first hypothesis was successfully tested. The next step will be to differentiate diverse carnivore types involving a wider range of carnivore-made BSM. The present study demonstrates that resolution increases when combining two different disciplines (taphonomy and artificial intelligence computing) in order to test new hypotheses that could not be addressed with traditional taphonomic methods.

Taphonomy of Yellow-legged Gull (Larus michahellis) pellets from the Chafarinas islands (Spain)

Fish are consumed by many predators in addition to humans. Identifying the agent responsible for an archaeological fish bone accumulation is a crucial yet far from straightforward task in the absence of diagnostic criteria. It is for this reason that exploring the features of fish bone collections produced by animals constitutes a key issue of archaeozoological research. In this paper, one such study is presented for the Yellow-legged Gull (Larus michahellis J.F. Naumann, 1840). A total of 48 pellets were collected in a colony of the species on two islands of the Chafarinas archipelago (Mediterranean Sea). The analyses demonstrate that fish remains, represented by 13 species and 1 genus, made up 93% of the 2789 identified remains. Most assemblages were dominated by the European pilchard (Sardina pilchardus (Walbaum, 1792)). Our study indicates that digestive processes modify skeletal elements through abrasion and fragmentation. Based on the modifications that were recorded, a set of diagnostic criteria is proposed to serve as proxies for spotting fish bone deposits produced by Yellow-legged Gulls on archaeological assemblages.

Horses and ancient people: zooarchaeological investigation of Muhkai 2a

The paper presents zooarchaeological analysis of the remains of Stenon horse Equus (Allohippus) stenonis from the site Muhkai 2a (layer 2), Central Dagestan, Russia. They are of special interest because of their large number and can testify to one of the first visits of an ancient man in the North Caucasus – about 1.95 million years ago. As a result of the comparison of the composition and ratio of the Stenon horse bones, their taphonomic features, showed that the site is the result of natural death of the animals. It is assumed that the bulk of the bones were laid in the deposits of a once shallow, periodically drying out and strongly silted reservoir with weakly flowing or standing water. After complete drying of the reservoir, the paleontological material was sealed in a clay mass, which in turn was buried during further geological processes. Based on this, we suggest a possible scenario for the formation of the bone accumulation. Most likely, it was a watering place for various animals, where some of them perished for natural reasons, for example, they got bogged down, drowned, and someone of them became prey for predators. Later, there was a burial of whole corpses, or parts thereof, transported to the pond. Obviously, the bodies of recently dead animals could not help attracting an ancient man, being an easily accessible source of protein food. The presence of artifacts and cut marks on the femur of Stenon horse indicate the presence of an ancient man in Muhkai 2a (layer 2), but the human activity seems to have played a minimal role in the taphocenosis forming.