6. Archaic and transitional hominins

2019 ◽  
pp. 73-85
Author(s):  
Bernard Wood
Keyword(s):  
Body Size ◽  
Tooth Size ◽  
Modern Humans ◽  
Fossil Species ◽  
Size And Shape

‘Archaic and transitional hominins’ considers the fossil species that almost certainly belong to the hominin clade, but which are still a long way from being like modern humans. The fossils that share more of their morphology with modern humans than they do with chimpanzees and bonobos, yet do not show the changes in jaw and tooth size and in body size and shape that characterize hominin species we are more comfortable with, including within our own genus Homo, are called ‘archaic’ hominins. The group of hominins that seem to be part archaic hominin and part Homo are called ‘transitional’ hominins.

scholarly journals Ontogeny of body size and shape of Antarctic and subantarctic fur seals

2007 ◽  
Vol 85 (12) ◽  
pp. 1275-1285 ◽  
Author(s):  
Sebastián P. Luque ◽  
Edward H. Miller ◽  
John P.Y. Arnould ◽  
Magaly Chambellant ◽  
Christophe Guinet
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Morphological Traits ◽  
Body Shape ◽  
Size And Shape ◽  
Fur Seals ◽  
Fur Seal ◽  
Adult Body ◽  
Weaning Age ◽  
Lactation Duration

Pre- and post-weaning functional demands on body size and shape of mammals are often in conflict, especially in species where weaning involves a change of habitat. Compared with long lactations, brief lactations are expected to be associated with fast rates of development and attainment of adult traits. We describe allometry and growth for several morphological traits in two closely related fur seal species with large differences in lactation duration at a sympatric site. Longitudinal data were collected from Antarctic ( Arctocephalus gazella (Peters, 1875); 120 d lactation) and subantarctic ( Arctocephalus tropicalis (Gray, 1872); 300 d lactation) fur seals. Body mass was similar in neonates of both species, but A. gazella neonates were longer, less voluminous, and had larger foreflippers. The species were similar in rate of preweaning growth in body mass, but growth rates of linear variables were faster for A. gazella pups. Consequently, neonatal differences in body shape increased over lactation, and A. gazella pups approached adult body shape faster than did A. tropicalis pups. Our results indicate that preweaning growth is associated with significant changes in body shape, involving the acquisition of a longer, more slender body with larger foreflippers in A. gazella. These differences suggest that A. gazella pups are physically more mature at approximately 100 d of age (close to weaning age) than A. tropicalis pups of the same age.

scholarly journals Influence of Lifestyle Aspects on the Association of Body Size and Shape with All-Cause Mortality in Middle-Aged Men and Women

Obesity Facts ◽  
2010 ◽  
Vol 3 (4) ◽  
pp. 252-260 ◽  
Author(s):  
Janne Bigaard ◽  
Jane Christensen ◽  
Anne Tjønneland ◽  
Birthe Lykke Thomsen ◽  
Kim Overvad ◽  
...  
Keyword(s):  
Body Size ◽  
Middle Aged ◽  
Men And Women ◽  
Size And Shape ◽  
All Cause Mortality

scholarly journals Recent origin of low trabecular bone density in modern humans

2014 ◽  
Vol 112 (2) ◽  
pp. 366-371 ◽  
Author(s):  
Habiba Chirchir ◽  
Tracy L. Kivell ◽  
Christopher B. Ruff ◽  
Jean-Jacques Hublin ◽  
Kristian J. Carlson ◽  
...  
Keyword(s):  
Body Size ◽  
Trabecular Bone ◽  
Homo Sapiens ◽  
Modern Human ◽  
Homo Erectus ◽  
Lower Limbs ◽  
Modern Humans ◽  
Human Skeleton ◽  
Trabecular Density ◽  
Fossil Hominins

Humans are unique, compared with our closest living relatives (chimpanzees) and early fossil hominins, in having an enlarged body size and lower limb joint surfaces in combination with a relatively gracile skeleton (i.e., lower bone mass for our body size). Some analyses have observed that in at least a few anatomical regions modern humans today appear to have relatively low trabecular density, but little is known about how that density varies throughout the human skeleton and across species or how and when the present trabecular patterns emerged over the course of human evolution. Here, we test the hypotheses that (i) recent modern humans have low trabecular density throughout the upper and lower limbs compared with other primate taxa and (ii) the reduction in trabecular density first occurred in early Homo erectus, consistent with the shift toward a modern human locomotor anatomy, or more recently in concert with diaphyseal gracilization in Holocene humans. We used peripheral quantitative CT and microtomography to measure trabecular bone of limb epiphyses (long bone articular ends) in modern humans and chimpanzees and in fossil hominins attributed to Australopithecus africanus, Paranthropus robustus/early Homo from Swartkrans, Homo neanderthalensis, and early Homo sapiens. Results show that only recent modern humans have low trabecular density throughout the limb joints. Extinct hominins, including pre-Holocene Homo sapiens, retain the high levels seen in nonhuman primates. Thus, the low trabecular density of the recent modern human skeleton evolved late in our evolutionary history, potentially resulting from increased sedentism and reliance on technological and cultural innovations.

A Rare Tooth Anomaly (Double Teeth) in Deciduous Teeth: A Case Report

2021 ◽  
Author(s):  
Fataneh Ghorbanyjavadpour
Keyword(s):  
Case Report ◽  
Lateral Incisor ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
Tooth Size ◽  
Genetic Characteristics ◽  
Size And Shape ◽  
Size Discrepancy ◽  
Tooth Size Discrepancy ◽  
Double Teeth

Introduction: The Size and shape of the teeth are genetic characteristics. Anomaly in tooth size and shape is due to disturbances in a sequence of morph differentiation and his to differentiation in tooth bud formation periods and is more common in permanent dentition than deciduous teeth. The most common tooth size discrepancy is in the upper lateral incisor and upper and lowers 2nd premolar teeth. About 5% of malocclusions are due to tooth size discrepancy. For having the best occlusion, we must have the appropriate size and shape of teeth. As there is a relation between deciduous and permanent teeth, proper evaluation and timely intervention are essential for achieving a good occlusion in anterior and posterior segments of permanent teeth. Thus we need interceptive orthodontic in mixed dentition period with a good treatment plan for removing the malformed tooth at the proper time and appliance therapy for eruption guidance of other teeth. Case Report: A rare tooth anomaly (double teeth) in deciduous teeth: The case reported here is a 9- years old boy with a delayed eruption of the right lower permanent lateral incisor and gemination of lower right deciduous canine and crowded upper incisors that refer to the orthodontic department of dental school of Ahvaz Jundishapur University of Medical Sciences on7th October of 2020. Conclusion: After creating patient’s file, the further steps of molding from the patient and gathering all diagnostic records such as panoramic radiography, intraoral photography was carried out and ordered to remove the malformed baby tooth afterward. In the next stage, on the patient’s treatment, we installed a strap onto the patient’s first permanent molars, remolded them, then created a lingual arch to maintain the vegetative space in the lower permanent canine and prevent its collapse, and increased the patient’s overbite.

scholarly journals The evolution of body size in termites

2021 ◽  
Vol 288 (1963) ◽  
Author(s):  
Nobuaki Mizumoto ◽  
Thomas Bourguignon
Keyword(s):  
Body Size ◽  
Size Reduction ◽  
Head Width ◽  
Termite Species ◽  
Fossil Species ◽  
Modern Species ◽  
Size Evolution ◽  
Phylogenetic Framework ◽  
Size Variability ◽  
Width Measurements

Termites are social cockroaches. Because non-termite cockroaches are larger than basal termite lineages, which themselves include large termite species, it has been proposed that termites experienced a unidirectional body size reduction since they evolved eusociality. However, the validity of this hypothesis remains untested in a phylogenetic framework. Here, we reconstructed termite body size evolution using head width measurements of 1638 modern and fossil termite species. We found that the unidirectional body size reduction model was only supported by analyses excluding fossil species. Analyses including fossil species suggested that body size diversified along with speciation events and estimated that the size of the common ancestor of modern termites was comparable to that of modern species. Our analyses further revealed that body size variability among species, but not body size reduction, is associated with features attributed to advanced termite societies. Our results suggest that miniaturization took place at the origin of termites, while subsequent complexification of termite societies did not lead to further body size reduction.

scholarly journals ProAna Worlds: Affectivity and Echo Chambers Online

Topoi ◽  
2021 ◽  
Author(s):  
Lucy Osler ◽  
Joel Krueger
Keyword(s):  
Anorexia Nervosa ◽  
Eating Disorder ◽  
Body Size ◽  
Disordered Eating ◽  
Sense Of Community ◽  
Genetic Predisposition ◽  
Size And Shape ◽  
Echo Chambers ◽  
Eating Practices ◽  
The Way

AbstractAnorexia Nervosa (AN) is an eating disorder characterised by self-starvation. Accounts of AN typically frame the disorder in individualistic terms: e.g., genetic predisposition, perceptual disturbances of body size and shape, experiential bodily disturbances. Without disputing the role these factors may play in developing AN, we instead draw attention to the way disordered eating practices in AN are actively supported by others. Specifically, we consider how Pro-Anorexia (ProAna) websites—which provide support and solidarity, tips, motivational content, a sense of community, and understanding to individuals with AN—help drive and maintain AN practices. We use C. Thi Nguyen’s work on epistemic “echo chambers”, along with Maria Lugones’ work on “worlds” and “ease”, to explore the dynamics of these processes. Adopting this broader temporal and intersubjective perspective, we argue, not only helps to further illuminate the experiential character of AN but also has important clinical and therapeutic significance.

Surirella subrotunda sp. nov. and Surirella parahelvetica sp. nov., two new diatom (Bacillariophyta) species from Lake Prespa, Macedonia

Phytotaxa ◽  
2014 ◽  
Vol 156 (3) ◽  
pp. 145 ◽  
Author(s):  
ALEKSANDRA CVETKOSKA ◽  
ZLATKO LEVKOV ◽  
PAUL B. HAMILTON
Keyword(s):  
Ancient Lakes ◽  
Similar Species ◽  
Ancient Lake ◽  
Lake Ohrid ◽  
Fossil Species ◽  
Size And Shape ◽  
Lake Prespa ◽  
Median Area

The genus Surirella is highly diverse and many taxa are reported as endemic, especially from ancient lakes and tropical continental regions. In ancient Lake Ohrid, 25 different Surirella species have been identified by different authors, five are considered to be endemic for the lake. In contrast, research on its sister Lake Prespa has been less rigorous and data for recent and fossil species of Surirella is very sparse. The number of Surirella taxa reported from Lake Prespa is 11; only one is considered an endemic for both lakes, Ohrid and Prespa. In this study, taxa from the genus Surirella were observed in a number of recent and fossil samples from Lake Prespa. Two taxa possess unique characters that distinguish them from known species. Their formal descriptions, based on detailed LM and SEM observations, are presented here. Surirella subrotunda sp. nov. is differentiated from other similar species by its valve outline, size, and shape of median area; it has been observed only in fossil diatom samples from core Co1215 recovered from Lake Prespa. Surirella parahelvetica sp. nov. is distinguished by its size, valve outline, number of alar canals and stria density.

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