Spatial differentiation of ectoparasites on small mammals

Different ectoparasitic species occur on different areas on the small mammal host: chiggers in the ear muzzle, ticks on the ears and other parts of the head, fleas and lice on the back and most gamasid mites on the posterior part of the host body.
The distribution might be affected by (1) the mechanical interference of the host. Thus attached species such as ticks and chiggers occur in areas where direct predation is limited and small and/or very mobile species are found on other parts of the body. (2) interaction between parasitic species. In areas where species meet, there might be a segregation in time or in space. Species such as Laelaps agilis (C. L. Koch) and Haemogamasus nidi Michael are most frequently found within a restricted area on the host, but differ in their seasonal occurrence. In other combinations of species, such as in fleas, there are marked differentiations in body areas used. These differentiations may be evolutionary fixed or manifested at first when species meet. (3) Abundance, where an increasing abundance enlarge the habitat used.     

Tick-borne zoonotic bacteria in wild and domestic small mammals in northern Spain

The prevalence and diversity of tick-borne zoonotic bacteria (Borrelia spp., Anaplasma phagocytophilum, Coxiella burnetii, and spotted fever group rickettsiae) infecting 253 small mammals captured in the Basque Country (Spain) were assessed using PCR and reverse line blot hybridization. Trapping sites were selected around sheep farms (study 1, 2000 to 2002) and recreational parks (study 2, 2003 to 2005). The majority of the studied mammals (162) were wood mice (Apodemus sylvaticus), but six other different species were also analyzed: yellow-necked mice (Apodemus flavicollis), shrews (Crocidura russula and Sorex coronatus), bank voles (Clethrionomys glareolus), domestic mice (Mus domesticus), and moles (Talpa europaea). The results showed an infection rate ranging from 10.7% to 68.8%, depending on the small mammal species. One C. russula shrew and one A. sylvaticus mouse gave positive reactions for A. phagocytophilum, and C. burnetii was detected in two domestic mice and one A. sylvaticus mouse in a farm. The DNA of Borrelia spp. was detected in 67 animals (26.5%), most of them presenting positive hybridization with the probe for Borrelia sp. strain R57, the new Borrelia species previously detected in small mammals in our region. Furthermore, a second PCR and reverse line blot hybridization specific for B. burgdorferi sensu lato revealed the presence of Borrelia afzelii in 6.3% of C. glareolus voles and 14.3% of S. coronatus shrews. All small mammals were negative for spotted fever group rickettsiae. These results highlight the relevance of small mammals as reservoirs of some zoonotic bacteria.     

Human remains from Valdegoba Cave (Huérmeces, Burgos, Spain).

Systematic excavations, begun in 1987, at the Valdegoba cave site in northern Spain have yielded the remains of five individuals associated with a Middle Paleolithic stone tool technology and Pleistocene fauna. A fragmentary mandible of an adolescent (VB1), preserving nearly a full set of teeth, exhibits a symphyseal tubercle and slight incurvatio mandibulae anterior on the external symphysis. Both the superior and inferior transverse tori are present on the internal aspect. A second individual (VB2) is represented by a set of ten deciduous teeth consistent with an age at death of 6-9 months. A proximal manual phalanx (VB3) displays a relatively broad head, a characteristic which is found in both Neandertals, as well as European Middle Pleistocene hominids. VB4 is a fourth metatarsal that lacks the distal epiphysis, indicating it comes from an adolescent individual, and has a relatively high robusticity index. Finally, VB5 is a fifth metatarsal of an adult. The VB1 mandible shows a combination of archaic characteristics as well as more specific Neandertal morphological traits. The VB2 deciduous teeth are very small, and both the metrics and morphology seem more consistent with a modern human classification. The postcranial elements are undiagnostic, U-Th dating has provided an age of >350 ka for the base of the sequence and a date of <73.2+/-5 ka for level 7, near the top. Faunal analysis and radiometric dates from other nearby Mousterian sites suggests that the Valdegoba site is correlative with oxygen isotope stages 3-6 on the Iberian peninsula, and an Upper Pleistocene age for the Valdegoba hominids seems most reasonable.     

A tall-spined ornithopod dinosaur from the Early Cretaceous of Salas de los Infantes (Burgos, Spain)

A tall-spined ornithopod dinosaur from the Pinilla de los Moros Formation (Upper Hauterivian-Lower Barremian) of Salas de los Infantes (Burgos, Spain) is described. The material consists of seven associated axial remains, including five middle dorsal vertebrae, a fragmentary neural spine and a dorsal rib, from a single medium-sized individual. This material was previously referred to Iguanodon cf. fittoni. It is characterised by having a high dorsal neurapophysis that is approximately 4.5 times the height of the centrum. The elongation and vertical orientation of the dorsal neural spines allow it to be distinguished from other ornithopods from the Wealden of Europe, including Hypselospinus and Barilium from the Valanginian, and Iguanodon and Mantellisaurus from the Barremian-Aptian. The material is here referred to Iguanodontia indet. because it is so incomplete, but it is potentially a distinct taxon. Among the ornithopods, only Ouranosaurus and the hadrosaurid Hypacrosaurus possess higher dorsal neural spines.     

Magnetochronology and stratigraphy at Gran Dolina section, Atapuerca (Burgos, Spain).

The Atapuerca Site (Burgos, N. Spain) is an extensive archaeological site which has yielded numerous human fossil remains. The Gran Dolina section, one of the open-air excavations and subject of this study, consists of a sedimentary infilling of 18 m thickness in a gallery originated by karstification of the host Cretaceous limestones. In this paper we present new stratigraphic and paleomagnetic evidence for the age and the sedimentary environment of the karst infilling where the archaeological site is located. Paleomagnetic dating places the hominids (Aurora stratum) in the Matuyama reversed Chron, hence before 780 ka. We also report evidence for a short normal polarity event at the bottom of the section that we speculate as being Jaramillo or Kamikatsura. The early and well-constrained date of the Atapuerca archaeological site, its location in the cul-de-sac we know as Europe, its stratigraphic context, the abundant fossil remains and the stone tool industry make it one of the most important localities for the question of the earliest human occupation in Europe.     

Integumental lesions caused by ectoparasites in a wild population of the side-blotched lizard (Uta stansburiana)

Histopathological effects of ectoparasites on integument were examined for a wild population of the side-blotched lizard Uta stansburiana. These included the trombiculid Neotrombicula californica, the pterygosomatid mite Geckobiella texana; the macronyssid mite Ophionyssus natricis (Macronyssidae) and the ixodid tick Ixodes pacificus. A diffuse inflammatory response occurred at the site of chigger and tick attachment which consisted of histiocyte, heterophil, fibroblast and lymphocyte infiltration that often extended into the dermis. Granuloma formation also was noted. The most prevalent parasite was N. californica which frequently occurred in large aggregations above the eyelids. Ectoparasites were most abundant from February through April.     

New foot remains from the Gran Dolina-TD6 Early Pleistocene site (Sierra de Atapuerca, Burgos, Spain)

This paper presents and describes new foot fossils from the species Homo antecessor, found in level TD6 of the site of Gran Dolina (Sierra de Atapuerca, Burgos, Spain). These new fossils consist of an almost complete left talus (ATD6-95) and the proximal three-quarters of a right fourth metatarsal (ATD6-124). The talus ATD6-95 is tentatively assigned to Hominin 10 of the TD6 sample, an adult male specimen with which the second metatarsal ATD6-70+107 (already published) is also tentatively associated. Analysis of these fossils and other postcranial remains has made possible to estimate a stature similar to those of the specimens from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca, Burgos, Spain). The morphology of the TD6 metatarsals does not differ significantly from that of modern humans, Neanderthals and the specimens from Sima de los Huesos. Talus ATD6-95, however, differs from the rest of the comparative samples in being long and high, having a long and wide trochlea, and displaying a proportionally short neck.     

Microparasites of wild small mammals

Little is known of the biology of the majority of microparasites except for those of medical or veterinary importance. It is suggested that techniques already developed for identification and quantification of these important parasites should be modified as necessary and extended to the study of other microparasites. Isolation and maintenance of microparasites in laboratory-maintained hosts will improve these diagnostic techniques and will also allow investigation of the biology of the parasites under controlled conditions. The value of laboratory-based experiments as an adjunct to ecological studies is emphasized. Problems of interpretation are indicated.     

Patterns of coexistence: ectoparasites on small mammals in northern Fennoscandia

The total aestival ectoparasitic burden of six small mammal species ( Sorex araneus, Clethrionomys glareolus, C. rutilus, C. rufocanus, Microtus agrestis , and M. oeconomus ) was investigated in terms of frequency distribution, frequency of occurrence, species diversity and joint occurrences. The mammals were collected in northern Fennoscandia during peak density years. The frequency distribution of the ectoparasites was best described as negative binomial on C. glareolus, M. agrestis , and M. oeconomus but not so on S. araneus, C. rutilus and C. rufocanus. The distribution did not fit the Poisson distribution in any species. The percentage of S. araneus that had ectoparasites was 49%, and of the microtidae species, 73-96% had ectoparasites. The median number of ectoparasites on the vole species was between 2 and 9 specimens of 1 or 2 species. There was a significant, positive correlation between the number of ectoparasitic species and the total number of individuals on all host species. Pairs of ectoparasitic species occurring together more or less often than expected by chance were found on all host species. However, the pairs rarely repeated themselves on the same host species under different environmental conditions, or on other host species under similar circumstances. Differences in total infestation between reproductive categories and sexes were observed in M. agrestis but not in S. araneus and C. glareolus.     

The TD6 level lithic industry from Gran Dolina, Atapuerca (Burgos, Spain): production and use.

Technological analysis of lithic artefacts recovered at the Aurora stratum of Atapuerca-TD6 shows that this Lower Pleistocene assemblage is similar to Mode I Technology (=Oldowan tradition) documented at many African sites. Diachronic comparison of the different levels of Gran Dolina allows us to conclude that this particular form of early European technology lacks the production of big flakes to manufacture large tools such as bifaces and cleavers. Rather, it is characterized by the presence of small artefacts, including flakes, denticulates, notches, and side-scrapers, many of which bear use-wear traces of butchery and woodworking. The dominant production technique is orthogonal, which is also reflected in the core recovered at the slightly older level of TD4. The raw materials also found in the Middle Pleistocene occupations at Atapuerca, though with significant proportion differences, have a local origin and include varieties of flint, quartzite and sandstone as well as limestone and quartz. TD6 small artefacts were made from most of these, although the retouched pieces seem to have been preferentially made of the best quality flint, i.e., Cretaceous flint, pointing to the existence of differential use of lithic material, and therefore, some degree of planned knapping behaviour. Most of the "cha?nes opératoires" or reduction sequences took place inside the cave, although some artefacts, elaborated on Cretaceous flint, seem to have been retouched off site, possibly near the supply sources.     

Understanding the ecology of mammalian carnivorans and herbivores from Valdegoba cave (Burgos, northern Spain) through stable isotope analysis

Stable carbon and oxygen isotope analyses of mammalian carnivoran and herbivore species from the late Pleistocene Valdegoba cave site in northern Spain imply competition and partitioning in resource use. In general, the data support the previously recognized ecology for the analyzed species. δ¹³C values show that the ecosystem around the cave was dominated by C₃ plants. The observed δ¹⁸O values are similar to what is found in modern environments. The analyzed bovids, Bos primigenius, Capra pyrenaica, and Rupicapra rupicapra, showed the most positive δ¹³C values. Bos primigenius had the most positive mean carbon isotope value and is suggested to feed on grasses in open environments. Values for Capra pyrenaica primarily indicate grass feeding, while Rupicapra rupicapra had the widest diet for the analyzed species, likely including grass and browse. Cervus elaphus, Equus ferus, Equus hydruntinus, and Stephanorhinus hemitoechus displayed more negative δ¹³C values indicating the use of similar resources. The smallest species analyzed, Castor fiber, displayed the most negative δ¹³C and δ¹⁸O values, implying a preference for eating C₃ plants and being semi-aquatic. The canids, Canis lupus and Vulpes vulpes, displayed the most positive δ¹³C and δ¹⁸O values, and overlap many of the sampled ungulate species. Positive δ¹⁸O values in canids implies that this group obtains much of its water from its prey, uses a different water source, or has physiological differences from the other carnivorans that influence oxygen isotope values. Lynx pardinus had values similar to the canids. Crocuta crocuta had δ¹³C values more negative than expected for a generalist predator. These values are likely due to concentration of diet on taxa from more forested environments. The most negative δ¹³C values are observed in the bears, Ursus arctos and Ursus spelaeus. These values are the likely result of hibernation and the inclusion of significant vegetation in bear diets.