The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species.
- MeSH
- diafýzy anatomie a histologie fyziologie MeSH
- femur anatomie a histologie fyziologie MeSH
- Hominidae anatomie a histologie fyziologie MeSH
- kostní denzita MeSH
- krček femuru anatomie a histologie fyziologie MeSH
- zkameněliny anatomie a histologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Jihoafrická republika MeSH
Long-term trends in robusticity of lower limb bones in the genus Homo through the Pleistocene until the present have been proposed, which have been interpreted as a consequence of decreasing levels of mobility and activity patterns, changes in lifestyle, and environmental factors. There has also long been evidence that skeletal strength increases over an individual's lifespan. This increase is caused by continuous bone remodeling that optimizes the structure of a bone to resist mechanical loadings and creates a balance between endosteal resorption and subperiosteal apposition. However, none of the previous studies of temporal trends in robusticity has considered both processes and analyzed how individual age-related robusticity might influence higher-level temporal trends. This paper therefore explores temporal trends in robusticity of lower limb long bones within the genus Homo and considers how individual ages-at-death can confound published evolutionary trends, given the fact that some aspects of relative bone strength tend to increase over individual lifespans. Cross-sectional diaphyseal properties of the midshaft and proximal femur and midshaft tibia of Pleistocene and early Holocene individuals, together with data on age-at-death are used to analyze changes in relative bone strength relative to individuals' ages and evolutionary time. The results show increasing bone strength in adulthood until the fourth decade and then a slight decrease, an observation that conforms to previously published results on recent human populations. However, no significant impact of age-at-death on the trends along an evolutionary trajectory has been detected. The evolutionary trends in femoral and tibial relative strength can be described as fluctuating, probably as a consequence of changing mobility patterns, environmentally and technologically influenced behaviors, and demographic processes. The differences between evolutionary trends published in several studies are explained primarily as a result of different ways of standardizing cross-sectional parameters for size, and differences in sample composition.
- MeSH
- biologická evoluce MeSH
- biomechanika MeSH
- dospělí MeSH
- femur anatomie a histologie fyziologie MeSH
- Hominidae anatomie a histologie fyziologie MeSH
- kostní denzita * MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- tibie anatomie a histologie fyziologie MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Cryptochromes are a ubiquitous group of blue-light absorbing flavoproteins that in the mammalian retina have an important role in the circadian clock. In birds, cryptochrome 1a (Cry1a), localized in the UV/violet-sensitive S1 cone photoreceptors, is proposed to be the retinal receptor molecule of the light-dependent magnetic compass. The retinal localization of mammalian Cry1, homologue to avian Cry1a, is unknown, and it is open whether mammalian Cry1 is also involved in magnetic field sensing. To constrain the possible role of retinal Cry1, we immunohistochemically analysed 90 mammalian species across 48 families in 16 orders, using an antiserum against the Cry1 C-terminus that in birds labels only the photo-activated conformation. In the Carnivora families Canidae, Mustelidae and Ursidae, and in some Primates, Cry1 was consistently labeled in the outer segment of the shortwave-sensitive S1 cones. This finding would be compatible with a magnetoreceptive function of Cry1 in these taxa. In all other taxa, Cry1 was not detected by the antiserum that likely also in mammals labels the photo-activated conformation, although Western blots showed Cry1 in mouse retinal cell nuclei. We speculate that in the mouse and the other negative-tested mammals Cry1 is involved in circadian functions as a non-light-responsive protein.
- MeSH
- antisérum chemie MeSH
- Canidae fyziologie MeSH
- čípky retiny - opsiny genetika MeSH
- čípky retiny fyziologie účinky záření ultrastruktura MeSH
- cirkadiánní rytmus fyziologie účinky záření MeSH
- exprese genu MeSH
- fylogeneze * MeSH
- Hominidae fyziologie MeSH
- imunohistochemie MeSH
- konformace proteinů MeSH
- kryptochromy chemie genetika MeSH
- magnetické pole MeSH
- medvědovití fyziologie MeSH
- Mustelidae fyziologie MeSH
- proteinové domény MeSH
- ptáci fyziologie MeSH
- savci klasifikace fyziologie MeSH
- světlo MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Klíčová slova
- vzpřímená poloha, vyšší vývojové stupně, antigravitační - elastický potenciál,
- MeSH
- antropologie metody trendy MeSH
- biologická adaptace fyziologie genetika MeSH
- biologická evoluce MeSH
- charakteristické znaky člověka MeSH
- fylogeneze * MeSH
- Hominidae fyziologie genetika růst a vývoj MeSH
- lidé MeSH
- pohybová aktivita * fyziologie MeSH
- postura těla * fyziologie MeSH
- sporty fyziologie psychologie MeSH
- Check Tag
- lidé MeSH
The origin of the fundamental behavioral differences between humans and our closest living relatives is one of the central issues of evolutionary anthropology. The prominent, chimpanzee-based referential model of early hominin behavior has recently been challenged on the basis of broad multispecies comparisons and newly discovered fossil evidence. Here, we argue that while behavioral data on extant great apes are extremely relevant for reconstruction of ancestral behaviors, these behaviors should be reconstructed trait by trait using formal phylogenetic methods. Using the widely accepted hominoid phylogenetic tree, we perform a series of character optimization analyses using 65 selected life-history and behavioral characters for all extant hominid species. This analysis allows us to reconstruct the character states of the last common ancestors of Hominoidea, Hominidae, and the chimpanzee-human last common ancestor. Our analyses demonstrate that many fundamental behavioral and life-history attributes of hominids (including humans) are evidently ancient and likely inherited from the common ancestor of all hominids. However, numerous behaviors present in extant great apes represent their own terminal autapomorphies (both uniquely derived and homoplastic). Any evolutionary model that uses a single extant species to explain behavioral evolution of early hominins is therefore of limited use. In contrast, phylogenetic reconstruction of ancestral states is able to provide a detailed suite of behavioral, ecological and life-history characters for each hypothetical ancestor. The living great apes therefore play an important role for the confident identification of the traits found in the chimpanzee-human last common ancestor, some of which are likely to represent behaviors of the fossil hominins.
- MeSH
- biologická evoluce * MeSH
- fylogeneze MeSH
- Hominidae fyziologie MeSH
- lidé MeSH
- Pan paniscus fyziologie MeSH
- Pan troglodytes fyziologie MeSH
- zkameněliny MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
There is still uncertainty about which species made the earliest known stone tools and what are the minimum biological attributes for stone tool manufacture. According to the “Morphocentric View”, the details of hand anatomy will tell us which fossil species made stone tools; according to the “Neurocentric View”, brain size and structure are the determining factors. Here, we espouse the Neurocentric View, and test it using information about the genetics of the hands and feet. We find that over 91% of the genes which affect the toes also affect the fingers, suggesting that evolution of hominid hands is tied to the evolution of our feet which are adapted for bipedalism. This and other evidence leads us to the conclusion that we must be cautious when using details of hand morphology to understand the origin and development of lithic technology
- MeSH
- antropologie metody MeSH
- biologická evoluce MeSH
- chování při používání nástrojů fyziologie MeSH
- genetika MeSH
- Hominidae anatomie a histologie fyziologie klasifikace MeSH
- lidé MeSH
- prsty nohy anatomie a histologie fyziologie růst a vývoj MeSH
- prsty ruky anatomie a histologie fyziologie růst a vývoj MeSH
- Check Tag
- lidé MeSH
- MeSH
- antropologie fyzická metody MeSH
- biologická evoluce MeSH
- Hominidae fyziologie genetika růst a vývoj MeSH
- kostra MeSH
- lidé MeSH
- lokomoce fyziologie genetika MeSH
- Macaca fyziologie genetika růst a vývoj MeSH
- muskuloskeletální systém - fyziologické jevy genetika MeSH
- nervový systém růst a vývoj MeSH
- ortopedie dějiny metody MeSH
- postura těla fyziologie MeSH
- primáti fyziologie genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
