A context for the last Neandertals of interior Iberia: Los Casares cave revisited.

INTRODUCTION AND OBJECTIVES: Although the Iberian Peninsula is a key area for understanding the Middle to Upper Paleolithic transition and the demise of the Neandertals, valuable evidence for these debates remains scarce and problematic in its interior regions. Sparse data supporting a late Neandertal persistence in the Iberian interior have been recently refuted and hence new evidence is needed to build new models on the timing and causes of Neandertal disappearance in inland Iberia and the whole peninsula. In this study we provide new evidence from Los Casares, a cave located in the highlands of the Spanish Meseta, where a Neandertal-associated Middle Paleolithic site was discovered and first excavated in the 1960's. Our main objective is twofold: (1) provide an updated geoarcheological, paleoenvironmental and chronological framework for this site, and (2) discuss obtained results in the context of the time and nature of the last Neandertal presence in Iberia. METHODS: We conducted new fieldwork in an interior chamber of Los Casares cave named 'Seno A'. Our methods included micromorphology, sedimentology, radiocarbon dating, Uranium/Thorium dating, palinology, microfaunal analysis, anthracology, phytolith analysis, archeozoology and lithic technology. Here we present results on site formation processes, paleoenvironment and the chronological setting of the Neandertal occupation at Los Casares cave-Seno A. RESULTS AND DISCUSSION: The sediment sequence reveals a mostly in situ archeological deposit containing evidence of both Neandertal activity and carnivore action in level c, dated to 44,899-42,175 calendar years ago. This occupation occurred during a warm and humid interval of Marine Isotopic Stage 3, probably correlating with Greenland Interstadial 11, representing one of the latest occurrences of Neandertals in the Iberian interior. However, overlying layer b records a deterioration of local environments, thus providing a plausible explanation for the abandonment of the site, and perhaps for the total disappearance of Neandertals of the highlands of inland Iberia during subsequent Greenland Stadials 11 or 10, or even Heinrich Stadial 4. Since layer b provided very few signs of human activity and no reliable chronometric results, and given the scarce chronostratigrapic evidence recorded so far for this period in interior Iberia, this can only be taken as a working hypothesis to be tested with future research. Meanwhile, 42,000 calendar years ago remains the most plausible date for the abandonment of interior Iberia by Neandertals, possibly due to climate deterioration. Currently, a later survival of this human species in Iberia is limited to the southern coasts.

Blood parasites in hooded crows (Corvus corone cornix) in Northwest Italy.

Haemoparasites and their effects on hooded crows (Corvus corone cornix) are poorly studied. The aims are to evaluate the prevalence of Haemoproteus spp./Plasmodium spp. or Leucocytozoon spp., to correlate this with gross and histopathological findings, and to investigate the association among infection and geographical origin, age, gender, parasite distribution and prevalence among organs. Hooded crows (n = 47) were collected within a regional culling programme from 3 districts in the province of Turin (Italy) and subjected to necropsy. Histological and molecular analyses were carried out on some tissues. Leucocytozoon spp. was detected in 46 crows (97.9%) by polymerase chain reaction (PCR), whereas 28 birds (59.6%) were found to be positive for Haemoproteus spp./Plasmodium spp. The distribution of parasites in several organs varied significantly, showing that Leucocytozoon spp. is ubiquitous in organs in contrast with Haemoproteus spp./Plasmodium spp., which have a specific predilection for spleen and lungs. The prevalence of Haemoproteus spp./Plasmodium spp. also differed significantly among the crows captured in the areas of the study. The high prevalence of haemoparasites emphasizes the success of ornithophilic vectors and the susceptibility of this species to infection. Differences in prevalence among the sites are probably due to orographic features of the areas, variations in vector species and density, or to crow population size or structure. In spite of the high infection rate, no gross and histological lesions were found. This finding further suggests an evolutionary adaptation between crows and avian blood parasites.

Prevalence of new and known species of haemoparasites in feral pigeons in northwest Italy.

BACKGROUND: Haemoparasites in feral pigeons have been studied in several countries but no data are available from Italy. The aim of this work was to evaluate the prevalence and diversity of Haemoproteus spp./Plasmodium spp. and Leucocytozoon spp. in feral pigeons from northwest Italy, as well as the association between infection and host age or sex. METHODS: Feral pigeons were collected during a regional culling programme from the Piedmont region (northwest Italy) and subjected to necropsy. Infections were detected from DNA extracted from the spleen following a nested PCR protocol. The association between sex or age and infection status was evaluated using the chi-squared test for independence or Fisher's exact test. RESULTS: Out of 51 animals, 15 were positive for Haemoproteus/Plasmodium spp. and eight for Leucocytozoon spp., with a significant difference between haemoparasites prevalence. There was no significant association between age or sex and infection status. The coinfection with different haemoparasites was very significant (p < 0.01), showing a greater relative risk to be infected by a second haemoparasite in birds already infected, in particular in male and in adult pigeons. DNA sequencing of Leucocytozoon spp. showed six different lineages in pigeons, and one of Haemoproteus and Plasmodium, respectively. CONCLUSIONS: Blood parasites are continuously circulating around the world, and the results presented in the paper suggest that cross infection of feral pigeons with haemoparasites typical of other migratory or nonmigratory bird species is possible. Moreover, the geographical location of Italy along the main migratory routes is a crucial factor to be considered for migratory birds, because they can be affected by blood parasites detected in feral pigeons, and vice versa.