Physiological implications of the bone histology of Syntarsus rhodesiensis (Saurischia: Theropoda)

Femora of Syntarsus rhodesiensis specimens of differing ontogenetic stages were sectioned and prepared for histological study. Features such as the structure of the cortical bone tissue, the degree of vascularisation and haversian substitution, and the general pattern of bone deposition through ontogeny, are described. The question of the bearing of bone histology on interpretation of the probable physiology of Syntarsus is also discussed

Assessing the biology of fossil vertebrates through bone histology

Main articleSoon after death and burial of an animal, the organic components of bone generally decay. The closely associated inorganic components (mainly apatite) are more resilient and even after millions of years of burial, preserve the spatial organisation of the collagen fibres and hence the structure of the bone. In the past fossil bone histology has been the subject of substantial research. Such studies have included a wide array of extinct vertebrates including fishes, amphibians, pelycosaurs, therapsids, ichthyosaurs, pterosaurs, and dinosaurs. The relative rate ofbone formation is indicated by the texture of the fibrillar matrix, while the overall nature of the primary compact bone provides a direct assessment of whether bone deposition was continuous or interrupted. The amount of secondary bone formation depicts the extent of primary bone resorption and subsequent redeposition. In addition, the internal organisation of bone indicates remodelling and relocation processes of growth, including functional adaptations of the bone morphology. Thus, osteohistology reflects ontogeny, growth dynamics, biomechanical adaptations, as well as various events that punctuate the life history of an animal.the Foundation for Research and Development (SA), and by the National Science Foundation (USA)

Growth and life habits of the Triassic cynodont Trirachodon, inferred from bone histology

Growth pattern and lifestyle habits of the Triassic non−mammalian cynodont Trirachodon are deduced from bone histol−ogy and cross−sectional geometry. Several skeletal elements of Trirachodon were examined in order to document histological changes during ontogeny, as well as histovariability in the skeleton. The bone histology of all the elements consists of a moderately vascularized, periodically interrupted, fibro−lamellar bone tissue. This suggests that the overall growth of Trirachodon was probably rapid during the favourable season, but decreased or ceased during the unfavourable season. As the environment is thought to have been semi−arid with seasonal rainfall, it is possible that Trirachodon was sensitive to such environmental fluctuations. Some inter−elemental histovariability was noted where the number and prominence of growth rings varied. Limb bone cross−sectional geometry revealed a relatively thick bone wall and sup−ports earlier proposals that Trirachodon was fossorial

Dicynodont (Therapsida) bone histology: phylogenetic and physiological implications

The bone histology of humeri of a number of taxonomically well established and easily definable dicynodont genera is described and compared. The bone of Aulacephalodon, Cistecephalus, Dicynodon, Endothiodon, Lystrosaurus, Kannemeyeria and Oudenodon consists of alternating fibro-lamellar and lamellated bone tissue, while that of Diictodon consists only of fibro-lamellar tissue. The presence of fibro-lamellar bone in all the genera studied, indicates that the bone was deposited rapidly, but the occurrence of lamellated bone tissue suggests that all the genera except Diictodon, also had intermittent periods of slow growth. This is the first time that a comparative study of bone histology of different dicynodont genera has been attempted by using one particular bone element to standardise intergeneric comparisons

Preparation of fossil bone for histological examination

Palaeo-histology is the branch of palaeontology concerned with the microscopic structure of fossil bone. Researchers entering the field for the first time become aware of a need for a concise description of a technique to prepare thin sections from fossil bone. This note aims to fill that need by describing the procedure used in a recent palaeohistological study (Chinsamy 1988, 1990, 1991, 1992). The technique described has been successfully applied to the bones of dinosaurs and mammal-like reptiles, as well as to archaeological samples ofhuman bone and also to defatted bone of recent taxa. There is no one 'correct' method of making sections of hard tissues like bones, but all existing techniques share a number of core processes in common (Enlow 1954; Enlow and Brown 1956; Honjo and Fischer 1965; Peabody 1961 ; Macfall and Wollin 1972; Buffrenil, Ricqles, Ray and Domning 1990). Although the method described here is specifically intended for use on bone, thin sections of fossilised wood have also been obtained using the same method

Osteohistology and palaeobiology of giraffids from the Mio-Pliocene Langebaanweg (South Africa)

The reconstruction of life history traits, such as growth rate, age at maturity and age at death can be estimated from the histological analysis of long bones. Here, we studied 20 long bones (metapodials, tibia and femora) of Sivatherium hendeyi and Giraffa cf. Giraffa jumae recovered from the Miocene–Pliocene locality of Langebaanweg on the West Coast of South Africa. We analysed the long bone histology and growth marks of juvenile and adult specimens of these taxa. Our results show that bone tissue types and vascular canal orientation varies during ontogeny, as well as between the different skeletal elements, and also across single cross sections of bones. Majority of our specimens appear to be still growing, with only an adult metacarpal of S. hendeyi being skeletally mature as indicated by the presence of an outer circumferential layer. We propose that the growth marks preserved in the cortices of the bones studied are most likely related to multiple catastrophic events as opposed to being annual/seasonal.Fil: Jannello, Juan Marcos. Universidad Tecnológica Nacional. Facultad Regional San Rafael. Instituto de Evolución, Ecología Histórica y Ambiente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Evolución, Ecología Histórica y Ambiente; ArgentinaFil: Chinsamy, Anusuya. University of Cape Town; Sudáfric