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.

Geochemical and sedimentary constraints on the formation of the Venta Micena early Pleistocene site (Guadix-Baza Basin, Spain)

Despite the paleontological relevance of the terrestrial Early Pleistocene Venta Micena bonebed (Baza Basin, Spain), it lacks a comprehensive geochemical/sedimentological study. Here, we demonstrate that the 1.5-m-thick Venta Micena limestone formed in a relatively small freshwater wetland/pond located at the periphery of the large saline Baza paleolake. Two microfacies are observed, with high and low contents of invertebrate fossils, and which originated in the centre and margin of the wetland, respectively. X-ray diffraction (XRD) mineralogy and paleohydrological characterization based on ostracod and bulk-rock geochemistry (δ13C and δ18O) indicate that the limestone reflects a general lowstand of the Baza lake, permitting the differentiation of freshwater wetlands that were fed by adjacent sources. Conversely, during highstands, the Baza lake flooded the Venta Micena area and the freshwater fauna was replaced by a saline one. Bulk-rock isotopic data indicate that the lower interval C1 of the limestone (bone-rich in marginal settings) displays general negative values, while the upper interval C2 (bone free) displays less negative values. The bones of predated mammals accumulated in the marginal areas, which were flooded and buried by recurring water-table fluctuations. Lake dynamics played a critical role in bone accumulation, which was previously considered as representing a hyena den.

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.

Taphonomic and spatial analyses from the Early Pleistocene site of Venta Micena 4 (Orce, Guadix-Baza Basin, southern Spain)

Venta Micena is an area containing several palaeontological sites marking the beginning of the Calabrian stage (Early Pleistocene). The richness of the fossil accumulation including species of Asian, African and European origin, makes Venta Micena a key site for the the palaeoecological and palaeoenvironmental study of southern Europe during the Early Pleistocene. Thus, research has been focused on Venta Micena 3, which was originally interpreted as a single palaeosurface associated with a marshy context, in which most of the fauna was accumulated by Pachycrocuta brevirostris. Recent excavations have unearthed a new site, Venta Micena 4, located in the same stratigraphic unit (Unit C) and in close proximity to Venta Micena 3. Here we show the first analyses regarding the taphonomic and spatial nature of this new site, defining two stratigraphic boundaries corresponding to two different depositional events. Furthermore, the taphonomic analyses of fossil remains seem to indicate a different accumulative agent than Pachycrocuta, thus adding more complexity to the palaeobiological interpretation of the Venta Micena area. These results contribute to the discussion of traditional interpretations made from Venta Micena 3.

A new species of dog from the Early Pleistocene site of Venta Micena (Orce, Baza Basin, Spain)

The site of Venta Micena (Orce, Spain), c. 1.6 Ma, preserves one the best paleontological records of the early Pleistocene large mammals fauna in Europe. Here we describe the specimens of the genus Canis Linnaeus, 1758 in the context of the late Villafranchian and Epivillafranchian fossil dogs from Eurasia. Anatomical and metric data suggest that the Venta Micena Canis form differs from the classical records of Canis etruscus Forsyth Major, 1877 and Canis arnensis Del Campana, 1913, and that it forms part of the younger Canis mosbachensis Soergel (1925) lineage, also recorded in two slightly younger sites of the Orce site complex, Barranco León and Fuente Nueva-3, dated to c. 1.4 Ma. The anatomy of the Venta Micena fossil material shows features that resemble the Canis forms from the Caucasian site of Dmanisi, dated to 1.8 Ma, and Canis ex gr. C. mosbachensis. Nevertheless, dental peculiarities support the creation of a new chrono-species, Canis orcensis n. sp., from the town of Orce. Morphological and paleoecological data suggest that this species probably consumed more vertebrate flesh than other similar sized early Pleistocene canids (i.e., a trend to hypercarnivory), which had more omnivorous dietary habits.

Palaeoenvironment of the earliest hominins in western Europe: the Guadix-Baza Basin

<p>The Guadix-Baza Basin (Granada Province, Southern Spain) is the richest area in Western Europe for the study of early hominin dispersal and evolution, having yielded the earliest localities with evidence of hominin occupation (a deciduous human molar, lithic industries and cutmarks) together with a rich large and small vertebrate assemblage dated to around 1.4 Ma. A key question is whether environmental changes were involved in the arrival of hominins in this region at this time. To answer this question, possible environmental differences between one older site lacking evidence for hominin occurrence (Venta Micena VM, ~1.6 Ma) and younger sites with undisputable evidence (Barranco León BL and Fuente Nueva-3 FN3, ~1.2-1.5 Ma) were investigated using various approaches, including carbon and oxygen isotopes in tooth enamel, tooth wear analysis, ecometrics and microvertebrates (amphibians, reptiles, mammals) as proxies for palaeoclimate.</p><p>Tooth enamel powders were collected from herbivorous mammal specimens from the three sites. For several specimens, enamel was sampled serially to document intra-annual dietary and/or habitat changes for the studied individuals. A large diversity of herbivorous taxa was sampled, including cervids, bovids, equids, rhinoceros, hippopotamus and mammoths. The analyses were conducted at the University of Tübingen (Senckenberg Centre for Human Evolution and Palaeoenvironment).</p><p>Carbon isotopic results from the three sites showed that the plants foraged by herbivores were essentially of C3 photosynthetic pathway (trees, shrubs and C3-grass adapted to mild growth season), which is consistent with the results of tooth wear analysis indicating browsing or mixed feeding with browsing preference for most taxa. The consumption of some C4 plants for some herbivores has been detected only in Barranco León, which is consistent with the results of palaeoclimatic investigations based on ecometrics and microvertebrate fauna, indicating a particularly wet and warm climate for this site compared to both others and colder conditions in Venta Micena, the site devoid of hominins. Oxygen isotopic results seem to be essentially related to browsing (high values) versus grazing (lower values) and to different habitats (lowest oxygen isotopic values for semi-aquatic hippos). The differences in isotopic results among taxa are in agreement with those of dietary preferences from mesowear tooth analysis. In addition, in a context of still Mediterranean climate with 4-months aridity during summer, isotopic variations within teeth suggest in some cases significant changes in foraging through a year, which could be related to local seasonal changes or mobility across areas with different vegetation types.</p><p>The first results of this multidisciplinary research project financed by the Leakey Foundation and a General Research Project from the Andalusian Regional Government help us to refine the palaeoenvironmental reconstruction around the time of the earliest arrival of hominins in Southern Spain. In combination with the climatic data provided by ecometrics and microvertebrate investigations, it allows us to develop a more detailed framework for the interpretation of the carbon and oxygen isotopic data from tooth enamel in a Mediterranean climate context, which corresponds to the type of climatic conditions where the earliest hominins occur in Europe in the Early Pleistocene.</p>

Los mamíferos del Plioceno y Pleistoceno de la Península Ibérica

España es el país con mayor número de yacimientos bien conservados, cantidad y calidad de fósiles de todo el continente europeo. Aquí se describe el patrimonio paleobiológico correspondiente al Plio-Pleistoceno (últimos 5,3 millones de años) registrado en los principales yacimientos con presencia de fósiles de grandes mamíferos de la Península Ibérica. Ningún otro país de nuestro entorno al norte del Mediterráneo ofrece mayores posibilidades para el estudio y disfrute de los registros paleontológicos del Plioceno y Pleistoceno. En este contexto destacan las principales cuencas sedimentarias como las de Besalú-Bañolas, Vallés, Calatayud-Teruel, o ya en el sur las cuencas intrabéticas, donde merece especial interés la de Baza y Guadix, con localidades emblemáticas como Baza 1 para el Plioceno, y como los yacimientos de Orce (Fuente Nueva 1 y 3, Venta Micena o Barranco León, entre otros) para el Pleistoceno inferior. También se hace referencia a otro tipo de yacimientos, como son los maares volcánicos pliocénicos del Camp dels Ninots en Cataluña, o el de las Higueruelas en la Mancha, a las terrazas fósiles de los grandes ríos peninsulares, así como a los extraordinarios registros kársticos, donde destaca el de Atapuerca en Burgos. Afortunadamente, este patrimonio es ya muy conocido y estudiado, y está publicado en las mejores revistas científicas mundiales. Sin embargo, salvo en el caso puntual de Atapuerca, su divulgación no ha llegado todavía a calar en el gran público, y su explotación cultural y turística necesita de un fuerte impulso en años venideros.