The Vallesian, 11.1-9 Ma, was a special time in the Vallès-Penedes basin near Barcelona, where a biodiversity hotspot existed. Europe had a subtropical climate, with rhinos, forest giraffes, lions,... Show moreThe Vallesian, 11.1-9 Ma, was a special time in the Vallès-Penedes basin near Barcelona, where a biodiversity hotspot existed. Europe had a subtropical climate, with rhinos, forest giraffes, lions, hyenas, flying squirrels and primates.Around 9.7 million years ago there was an abrupt collapse in diversity; the so-called 'Vallesian Crisis'. This was seen as the transition point to a climate with more seasonality and open landscapes.Using a fossil dataset from Miocene Eurasia, the influence of dataset quality on the severity of this crisis, which animals were most affected and their distribution patterns was studied.The crisis’ victims have three things in common: they are mainly forest dwellers, they date back to the Middle Miocene (16-11.1 Ma), and they are rare during the early Vallesian. The high Vallesian biodiversity was caused by the arrival of new immigrants in addition to older transient groups, possibly due to the unique coastal conditions.Major differences existed between the coastal region and the interior of the Iberian Peninsula. Some species appeared in the Vallès-Penedès, but never reached the inland. The 'Vallesian Crisis', while seen understandably as a time of abrupt and severe extinction, was thus largely a local turnover event. Show less
Laffoon, J.E.; Sonnemann, T.F.; Antczak, M.M.; Antczak, A. 2018
Archeological excavations of Amerindian sites on Dos Mosquises Island, Los Roques Archipelago, Venezuela, uncovered a wide range of evidence reflecting seasonal exploitation of local resources and... Show moreArcheological excavations of Amerindian sites on Dos Mosquises Island, Los Roques Archipelago, Venezuela, uncovered a wide range of evidence reflecting seasonal exploitation of local resources and multiple ritual depositions of large quantities of ceramic figurines, lithics, and faunal remains. Zooarchaeological analysis revealed the presence of modified and unmodified bones and teeth from numerous imported mammal species. Local geographic and environmental conditions preclude permanent establishment of terrestrial mammal populations and as such, there are no native mammalian taxa on the island itself or the surrounding oceanic archipelago. The presence of these faunal remains on Dos Mosquises can be attributed to the intentional movement of animal resources from the mainland to Los Roques by indigenous groups in the Late Ceramic Age (~AD 1200–1500). Despite attributions to a mainland source region, little else is known about the origins of these unique specimens. Here, we apply strontium (87Sr/86Sr), oxygen (δ18O), and carbon (δ13C) isotope analyses of tooth enamel from various archeologically recovered taxa including deer, peccary, tapir, ocelot, margay, opossum, fox, and weasel to investigate their geographic origins via comparisons with macro-regional models of precipitation δ18O and bioavailable 87Sr/86Sr. The 87Sr/86Sr results are highly variable both for the overall assemblage and between specimens within the same taxa, indicating origins from different geochemical environments of mainland South America. The combined archeological and isotopic evidence are consistent with origins within the late pre-colonial Valencioid Sphere of Interaction which encompassed the Lake Valencia Basin, surrounding regions, and several offshore island groups including Los Roques archipelago. Show less
Ponomarev, Dmitry; Kolfschoten, Thijs van; Plicht, Johannes van der; Kosintsev, Pavel 2015
