Journal ArticleDOI
Anatomy and function of expanded ribs in certain edentates and primates.
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TLDR
Anteroposteriorly expanded ribs occur in all three species of myrme-cophagids (Cyclopes didactylus, Tamandua tetradactyla, and Myrmecophaga tridACTyla) and Functionally, expanded ribs may increase the stability of the thorax, which, in turn, increases the stability in the vertebral column.Abstract:
Anteroposteriorly expanded ribs occur in all three species of myrme-cophagids (Cyclopes didactylus, Tamandua tetradactyla, and Myrmecophaga tridactyla). Similar rib expansion occurs in some armadillos (for example, Dasypus novemcinctus, Priodontes giganteas, Euphractus sexcinctus) and in some primates (Arctocebus calabarensis, Perodicticus potto, and Loris tardigradus). In C. didactylus and A. calabarensis rib expansion is so extensive that adjacent ribs imbricate. the epaxial and hypaxial musculature related to the expanded ribs in all three myrmecophagid species is described. the intercostal spaces in T. tetradactyla and M. tridactyla are approximately 50 per cent narrower than in various other mammals with unexpanded ribs; the intercostal musculature of these two species is approximately twice as thick as that in other mammals with unexpanded ribs. the proportion of intercostal musculature in C. didactylus is comparable to that in other mammals. Functionally, expanded ribs may increase the stability of the thorax, which, in turn, increases the stability of the vertebral column. This specialization in T. tetradactyla and M. tridactyla probably relates to their fossorial habitus; the trunk is stabilized during fossorial activity by xenarthrous processes in the lumbar region and by expanded ribs and robust intercostal muscles in the thorax. in strictly arboreal forms such as C. didactylus and A. calabarensis, lumbo-thoracic stability may be employed in methodical arboreal locomotion. C. didactylus, at least, is able to anchor itself with hind feet and tail and extend its trunk and forelimbs to reach an adjacent branch—a feat requiring unusual lumbothoracic stability.read more
Citations
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Book ChapterDOI
Evaluating the Mitten-Gliding Hypothesis for Paromomyidae and Micromomyidae (Mammalia, “Plesiadapiformes”) Using Comparative Functional Morphology of New Paleogene Skeletons
Doug M. Boyer,Jonathan I. Bloch +1 more
TL;DR: Vertebrate paleontologists have struggled to understand the nature of the phylogenetic relationship of “plesiadapiforms” to the extant and extinct members of crown group Primates [= Euprimates], since Plesiadapis was first described by Gervais in 1877.
Journal ArticleDOI
Functional aspects of strepsirrhine lumbar vertebral bodies and spinous processes.
TL;DR: The results of the study broaden the understanding of postcranial adaptation in primates, while providing an extensive comparative database for interpreting vertebral morphology in fossil primates.
Journal ArticleDOI
The osteology and relationships of the Millerettidae (Reptilia: Cotylosauria)
TL;DR: It is suggested that the Millerettidae may have given rise directly to the Squamata and the Archo-sauria and Rhynchocephalia probably had an entirely independent origin.
Journal ArticleDOI
Locomotion of the slow loris in a designed substrate context
Daria Dykyj,Daria Dykyj +1 more
TL;DR: Analysis of locomotion of a slow loris in a designed substrate context composed of dowels suggests that the interaction between the cheiridea and substrate parameters frequently determines the expression of other features of locomotor performance.
Journal ArticleDOI
Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru.
TL;DR: The bones of terrestrial pilosans (sloths and anteaters) are much more compact than the mean mammalian condition, which suggests that the osteosclerosis of Thalassocnus may represent an exaptation, and the most detailed data about the gradual acquisition of aquatic adaptations among tetrapods is assessed.
References
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Journal ArticleDOI
Role of the Trunk in Stability of the Spine
TL;DR: There is a great discrepancy between the force that can theoretically be applied to the spine if the role of intracavitary pressures is ignored and theforce that can be tolerated experimentally by the isolated ligamentous human spine.
Journal ArticleDOI
Some mechanical tests on the lumbosacral spine with particular reference to the intervertebral discs; a preliminary report.
TL;DR: The investigations reported here represent an effort to explore the possibilities of obtaining quantitative data on the mechanical properties of the lumbosacral spine by applying to fresh autopsy specimens of the spine testing techniques used in civil or mechanical engineering.