Small mammals (Insectivora, Rodentia, Lagomorpha) from the Early Pleistocene hominin-bearing site of Dmanisi (Georgia).

Small mammals (insectivores, rodents, and lagomorphs) from Dmanisi are here reviewed for the first time and used as a tool for paleoenvironmental proxies. The small mammal faunal list is composed of shrews (Beremendia fissidens, cf. Beremendia minor, Crocidura kornfeldi), hamsters (Cricetulus sp., Allocricetus bursae), gerbils (Parameriones aff. obeidiyensis), murids (Apodemus cf. atavus), arvicolids (Mimomys pliocaenicus, Mimomys aff. pusillus), and pikas (Ochotona sp.). A paleoenvironmental reconstruction based on the habitat weighting method has been applied to the rodent assemblage. According to this method, the most common elements indicate an open-dry habitat (36.5%), followed by water edge (25.7%) and rocky (21.0%) elements. Open-wet (15.5%) and woodland elements (1.3%) are rare. Therefore, the habitat occupied by the hominids of Dmanisi was characterized by the prevalence of arid conditions, from steppe or semi-desert to open Mediterranean forest, with stony or rocky substrate and bushy areas. The presence of permanent aquatic environments is also documented. From a biogeographic point of view, the small mammal community from Dmanisi is composed mainly by Western or Central Asian elements, with a poor representation of European elements (Mimomys, Apodemus). It is concluded that Dmanisi hominins most possibly had ecological requirements which were different from those of the Early Pleistocene hominins from Western Europe, which settled on wetter habitats. It could be also possible that Dmanisi hominins entered Southern Caucasus at an interglacial phase before the deposition of the Dmanisi site.

Chronological and environmental context of the first hominin dispersal into Western Europe: The case of Barranco León (Guadix-Baza Basin, SE Spain).

The early Pleistocene site of Barranco León (Guadix-Baza Basin, SE Spain), dated to 1.4 Ma (millions of years ago), records the oldest hominin occurrence in Western Europe, as evidenced by the discovery of one tooth and thousands of Mode 1 stone tools. In this paper a detailed analysis of the microvertebrate content of the D1 and D2 units from this site is presented. The early Pleistocene in the Guadix-Baza Basin is characterized by a sharp climatic deterioration, which possibly impeded the settlement of this region by the early hominin population from the southern Caucasus. Shortly afterwards, when the climatic conditions were again favorable, a hominin presence is suddenly evidenced at the units D1 and D2 of Barranco León. According to the microvertebrate analysis of these units, the mean annual temperature at the time of deposition was significantly higher than 13 °C, with prevalent humid conditions. However, although most of the species were inhabitants of water edges, an open landscape was present in the vicinity of the lake. The data reported here clearly support the idea that the early hominin occupation of Europe was strongly constrained by climatic and environmental conditions, rather than by physiography or cultural factors.

Variationin the ilium of central European water frogs Pelophylax (Amphibia, Ranidae) and its implications for species-level identification of fragmentary anuran fossils.

BACKGROUND: In the opinion of all field herpetologists and archaeozoologists, green frogs (living and sub-fossil specimens)are among the most difficult European amphibians to identify. Here, we examine the intra- and interspecific variation in both continuous and discrete iliac characters for refining the criteria for species-level identification among Europeangreen frogs Pelophylaxridibundus,Pelophylaxlessonae andtheir associated klepton Pelophylaxkl.P.esculentus (Amphibia,Ranidae). RESULTS: Atotal of 454 ilia of modern green frogs from the former German Democratic Republic have been studied: 168 for P.lessonae (86of males and 82 of females), 118 for P.ridibundus (44of males and 74 of females) and 168 for P.kl.P.esculentus (86of males and 82 of females). The origin, sex, population structure and phenotype are known for each of the studied specimens. Eight variables have been taken (one angle and seven measurements), mainly on the distal part of the element in order to be able to apply them to fragmentary fossil ilia. Interspecific variations, sexual dimorphism and population structure have been investigated. Results suggest that the secure determination of a single fossil ilium at species level is quite impossible, but that at population level, it may be possible to distinguish between a 'pure' species or a 'pure' species plus its cohabiting hybrid form, as some minor differences have been evidencedin particular in the angle of the tubersuperior inrelation to iliac's main axis (character 2) and the width of the parsascendens (character8); two parameters significantly non size-dependent. No sexual dimorphism has been detected, except for P.lessonae. CONCLUSIONS: We propose here a new biometrical method in order to differentiate between the fossil ilia of central European water frogs (genus Pelophylax) at population level.

Walk the line: 600000 years of molar evolution constrained by allometry in the fossil rodent Mimomys savini.

The allometric-constraint hypothesis states that evolutionary divergence of morphological traits is restricted by integrated growth regulation. In this study, we test this hypothesis on a time-calibrated and well-documented palaeontological sequence of dental measurements on the Pleistocene arvicoline rodent species Mimomys savini from the Iberian Peninsula. Based on 507 specimens representing nine populations regularly spaced over 600 000 years, we compare static (within-population) and evolutionary (among-population) allometric slopes between the width and the length of the first lower molar. We find that the static allometric slope remains evolutionary stable and predicts the evolutionary allometry quite well. These results support the hypothesis that the macroevolutionary divergence of molar traits is constrained by static allometric relationships.

Age and date for early arrival of the Acheulian in Europe (Barranc de la Boella, la Canonja, Spain).

The first arrivals of hominin populations into Eurasia during the Early Pleistocene are currently considered to have occurred as short and poorly dated biological dispersions. Questions as to the tempo and mode of these early prehistoric settlements have given rise to debates concerning the taxonomic significance of the lithic assemblages, as trace fossils, and the geographical distribution of the technological traditions found in the Lower Palaeolithic record. Here, we report on the Barranc de la Boella site which has yielded a lithic assemblage dating to ∼1 million years ago that includes large cutting tools (LCT). We argue that distinct technological traditions coexisted in the Iberian archaeological repertoires of the late Early Pleistocene age in a similar way to the earliest sub-Saharan African artefact assemblages. These differences between stone tool assemblages may be attributed to the different chronologies of hominin dispersal events. The archaeological record of Barranc de la Boella completes the geographical distribution of LCT assemblages across southern Eurasia during the EMPT (Early-Middle Pleistocene Transition, circa 942 to 641 kyr). Up to now, chronology of the earliest European LCT assemblages is based on the abundant Palaeolithic record found in terrace river sequences which have been dated to the end of the EMPT and later. However, the findings at Barranc de la Boella suggest that early LCT lithic assemblages appeared in the SW of Europe during earlier hominin dispersal episodes before the definitive colonization of temperate Eurasia took place.