• MeSH
• anatomie srovnávací MeSH
• embryonální struktury MeSH
• nos MeSH
• paleontologie MeSH
• plazi MeSH
• ptáci MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• anatomie srovnávací MeSH
• dentin anatomie a histologie   MeSH
• elektronová mikroskopie MeSH
• zubní sklovina anatomie a histologie   MeSH

The origin of living Homo sapiens has once again been the subject of much debate. Genetic data on present human population relationships and data from the Pleistocene fossil hominid record are used to compare two contrasting models for the origin of modern humans. Both genetics and paleontology support a recent African origin for modern humans rather than a long period of multiregional evolution accompanied by gene flow.

• MeSH
• biologická evoluce * MeSH
• Haplorrhini anatomie a histologie   genetika   MeSH
• lebka anatomie a histologie   MeSH
• lidé MeSH
• paleontologie * MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Afrika MeSH
• Československo MeSH
• Čína MeSH

Murid rodents (Rodentia: Muridae) represent the most diverse and abundant mammalian family. In this study, we provide a refined set of fossil calibrations which is used to reconstruct a dated phylogeny of the family using a multilocus dataset (six nuclear and nine mitochondrial gene fragments) encompassing 161 species representing 82 murid genera from four extant subfamilies (Deomyinae, Gerbillinae, Lophiomyinae and Murinae). In comparison with previous studies on murid or muroid rodents, our work stands out for the implementation of nine robust fossil constraints within the Muridae thanks to a thorough review of the fossil record. Before being assigned to specific nodes of the phylogeny, all potential fossil constraints were carefully assessed; they were also subjected to several cross-validation analyses. The resulting phylogeny is consistent with previous phylogenetic studies on murids, and recovers the monophyly of all sampled murid subfamilies and tribes. Based on nine controlled fossil calibrations, our inferred temporal timeframe indicates that the murid family likely originated in the course of the Early Miocene, 22.0-17.0 million years ago (Ma), and that most major lineages (i.e. tribes) started diversifying ca. 10 Ma. Historical biogeography analyses support the tropical origin for the family, with an initial internal split (vicariance event) between Afrotropical and Oriental (Indomalaya and Philippines) lineages. During the course of their diversification, the biogeographic pattern of murids is marked by several dispersal events toward the Australasian and the Palearctic regions. The Afrotropical region was also secondarily colonized at least three times from the Indomalaya, indicating that the latter region has acted as a major centre of diversification for the family.

• MeSH
• Bayesova věta MeSH
• časové faktory MeSH
• fylogeneze * MeSH
• fylogeografie MeSH
• kalibrace MeSH
• Muridae klasifikace   MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: The diploic channels appear to be more developed in humans than in nonhuman primates, suggesting they may be relevant in evolutionary biology. This study is aimed at providing a segmentation procedure for diploic channels and CT analysis, a quantitative description of their variation in modern humans, and paleoanthropological case-studies. MATERIALS AND METHODS: CT data were used for the 2D and 3D visualization, rendering, and measure, of diploic channels in modern and fossil hominids. We analyzed 20 modern human skulls and three Neanderthals. The effect of different resolution factors was evaluated. A specific protocol was designed to segment the vascular network and localize the main branches, reducing the noise of the cancellous bone. RESULTS: We provide a quantitative description of the frontal, parietal, and occipital diploic networks in modern humans and in three Neanderthals. There is a correlation in the degree of vascularization among the different vault areas. No side differences can be detected. The diploic network is commonly connected with the meningeal artery at the temporal fossa, with the emissary veins at the occipital bone, and with the venous sinuses at the parieto-occipital areas. The channels are more developed in the parietal areas. The three Neanderthals show a vascular development, which is in the lower range of the modern human variation. CONCLUSIONS: Modern humans display a large variation in their morphological patterns, being the parietal area the most vascularized. The pattern of the diploic channels may be relevant in anthropology, medicine, and paleontology, taking into account their possible involvement in thermoregulation.

• MeSH
• antropologie fyzická MeSH
• dospělí MeSH
• lebka * anatomie a histologie   krevní zásobení   radiografie   MeSH
• lidé MeSH
• neandertálci anatomie a histologie   MeSH
• počítačová rentgenová tomografie MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Konspekt
• Anatomie člověka a srovnávací anatomie
• NLK Obory
• anatomie

Trilobites offer the opportunity to explore postembryonic development within the fossil record of arthropod evolution. In contrast to most trilobites, the Silurian proetid Aulacopleura konincki from the Czech Republic exhibits marked variation in the mature number of thoracic segments, with five morphs with 18-22 thoracic segments. The combination of abundant articulated specimens available from a narrow stratigraphic interval and segmental intraspecific variation makes this trilobite singularly useful for studying postembryonic growth and segmentation. Trunk segmentation followed a hemianamorphic pattern, as seen in other arthropods and as characteristic of the Trilobita; during a first anamorphic phase, segments were accreted, while in the subsequent epimorphic phase, segmentation did not proceed further despite continued growth. Size increment during the anamorphic phase was targeted and followed Dyar's rule, a geometric progression typical of many arthropods. We consider alternative hypotheses for the control of the switch from anamorphic to epimorphic phases of development. Our analysis favors a scenario in which the mature number of thoracic segments was determined quite early in development rather than at a late stage in association with a critical size threshold. This study demonstrates that hypotheses concerning developmental pattern and control can be tested in organisms belonging to an extinct clade.

• MeSH
• biologická evoluce * MeSH
• biologické modely * MeSH
• členovci růst a vývoj   MeSH
• tělesné váhy a míry MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH

• MeSH
• Ginkgo biloba genetika   MeSH
• polyploidie * MeSH
• Publikační typ
• dopisy MeSH
• práce podpořená grantem MeSH

Sex is a biological trait fundamental to the study of hominin fossils. Among the many questions that can be addressed are those related to taxonomy, biological variability, sexual dimorphism, paleoobstetrics, funerary selection, and paleodemography. While new methodologies such as paleogenomics or paleoproteomics can be used to determine sex, they have not been systematically applied to Pleistocene human remains due to their destructive nature. Therefore, we estimated sex from the coxal bone of the newly discovered pelvic remains of the Regourdou 1 Neandertal (Southwest France, MIS 5) based on morphological and metric data employing two methods that have been recently revised and shown to be reliable in multiple studies. Both methods calculate posterior probabilities of the estimate. The right coxal bone of Regourdou 1 was partially reconstructed providing additional traits for sex estimation. These methods were cross validated on 14 sufficiently preserved coxal bones of specimens from the Neandertal lineage. Our results show that the Regourdou 1 individual, whose postcranial skeleton is not robust, is a male, and that previous sex attributions of comparative Neandertal specimens are largely in agreement with those obtained here. Our results encourage additional morphological research of fossil hominins in order to develop a set of methods that are applicable, reliable, and reproducible.

• MeSH
• genomika MeSH
• Hominidae * MeSH
• lidé MeSH
• neandertálci * anatomie a histologie   MeSH
• paleontologie MeSH
• zkameněliny MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Francie MeSH

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to map the matrix (Ca, P) and trace (Ba, Sr, Zn) elements in the root section of a fossilized brown bear (Ursus arctos) tooth. Multielemental analysis was performed on a (2.5 × 1.5)cm(2) area. For elemental distribution, a UP 213 laser ablation system was coupled either with a quadrupole or a time of flight ICP-MS. The cementum and dentine on the slice of the sample surface were clearly distinguishable, especially changes in elemental distribution in the summer and winter bands in the fossil root dentine. Migration and diet of U. arctos were determined on the basis of fluctuations in Sr/Zn ratio and their contents. Quantification was accomplished with standard reference material of bone meal (NIST 1486) and by the use of electron microprobe analysis (EMPA). Changes in Sr/Zn and Sr/Ba ratios relating to the season, and composition of food during the lifetime of the animal are discussed on basis of analysis of light stable isotopes. It was observed that there was an increase in the Sr/Zn ratio during the winter season caused by a reduction of food intake during hibernation. Above mentioned inferences drawn from elemental data obtained by LA-ICP-MS were confirmed independently by determination of carbon, nitrogen and strontium isotopes. Moreover, diagenesis and its interfering influence on the biogenic composition of cementum and dentine were resolved. According to the distribution and/or content of the element of interest, post-mortem alterations were revealed. Namely, U, Na, Fe, Mg and F predicate about the suitability of the selected area for determination of migration and diet.

• MeSH
• hmotnostní spektrometrie metody   MeSH
• lasery MeSH
• medvědovití anatomie a histologie   MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH