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C E Oxnard

Publications and source records attributed to C E Oxnard.

At least 19 recordsLinked to original sources
PubMed1995

Age-related bone resorption in the normal incus: a case of maladaptive remodelling?

The changes that occur in the normal human incus with age have been investigated. Evidence for age-related changes in this ossicle, especially in the region of the long process, has been accumulating over the last 30-40 years and yet they have neither been confirmed quantitatively nor explained satisfactorily. In this study the results of a morphometric study of the long processes of a series of normal incudes are presented. These demonstrate that the lenticular and long processes undergo progressive symmetric resorption with advancing age. We consider these findings in the light of previous considerations of incudal remodelling and propose that these remodelling changes may reflect a normal adaptive response to the biomechanical milieu of the human middle ear.

Aged↗
PubMed1987

Morphometrics and niche metrics in prosimian locomotion: an approach to measuring locomotion, habitat, and diet.

Locomotor morphology, it is recognized, cannot be understood without an understanding of locomotor behavior. The interaction of locomotor anatomy and behavior has been successfully analyzed for single species and species pairs. Broader generalizations, however, require the demonstration of anatomical/behavioral associations for numerous sets of species. To accomplish this it is necessary to develop a method for the simultaneous quantitative description and comparison of many different parameters of the locomotor niche: locomotor behaviors, habitat usages, and diets. As a start towards achieving this we present a multidimensional approach to the description of functional parameters of the niche for prosimians. We derive quantitative evaluations of locomotor activity, habitat utilization, and diet for each of 27 species, using field data, film and video records, and the available literature. These parameters are then displayed graphically and clustered to provide profiles for comparisons both of species and variables. The multidimensional profiles reveal valuable information about activity, environment and diet, and their interactions. They permit closer comparisons with equivalent multidimensional information about prosimian structure, based on morphometric studies. The method gives useful graphical and statistical techniques for interspecific comparisons of morphometrics and niche metrics.

Animals↗
PubMed1980

Functional articulation of some hominoid foot bones: implications for the Olduvai (hominid 8) foot.

Previous observations on twelve fossil foot bones (Olduvai 8: Day and Napier, '64) together with multivariate morphometric studies of one of them, the talus (Day and Wood, '68) suggested human-like bipedality for this foot. Subsequent studies showed the conclusions on the talus to be wrong: The fossil talus, as defined by eight measures, does not resemble that of man but is reminiscent of those of creatures known (extant--orangutans) or believed (extinct--some fossil apes and monkeys) to be arboreal in habitus (Oxnard '72; Lisowski, et al., '74, '76). A reassessment of the entire Olduvai 8 foot is therefore necessary to answer the problem posed by a foot that has a non-human talus with, apparently, a human arched pattern of the remaining tarsal and metatarsal bones. The dry bones of a series of feet of extant hominoids have been rearticulated and are found to be close to the actual relationships presented by dissected specimens in which ligaments, articular cartilages and soft tissues are present. Similar rearticulation applied to casts of the individual Olduvai foot bones produces a structure that is not arched in the same manner as the human foot; it displays features that ally it more closely with the feet of various apes. Sections of casts of the already rearticulated Olduvai foot (from both the Wenner Gren Foundation and the Kenya National Museums) show that the human-like appearance of the original rearticulation is due to a series of incorrect osteological alignments. Although casts do not permit study of surface features, the dimensions of the casts are sufficiently accurate to permit rearticulation in this manner. It is thus clear, a) that the Olduvai foot is not adated for bipedality in the manner of man, and b) that it displays features in which it resembles the feet of arboreal creatures. Such anatomical characters as relate to bipedality in the fossil suggest usage as in an arboreal species that also walks bipedally with flattened arches (like a chimpanzee or gorilla) rather than with the high arches of man.

Adult↗
PubMed1977

Morphometric affinities of the human shoulder.

A recent discussion by Corruccini and Ciochon ('76) implies that previous multivariate morphometric studies of the shoulder, reviewed in Oxnard ('73), have been misinterpreted because due allowance was not made for the overall sizes of the specimens. Results that were given functional significance in the earlier investigations are cited as being due at least in part to overall bodily size. Although examination of the range of genera selected for mention by corruccini and Ciochon seems superficially to support this view, it is demonstrated here that examination of the full range of genera in the earlier studies refutes, unequivocally, that suggestion. The discussion by Corruccini and Ciochon ('76) also implies that the more complex size correction applied in their study produces a result different from that of the previous workers. Again, although perusal of the particular part of the earlier study selected for discussion by Corruccini and Ciochon would appear to bear that out, it is demonstrated here that comparisons with all parts of the earlier results provide a different picture. Thus the main result of Corruccini and Ciochon replicates rather closely a more restricted part of the earlier result not mentioned by Corruccini and Ciochon. The difference between Corruccini and Ciochon's principal result and the main result of the prior authors is shown to rest upon the difference between the more restricted earlier study of "residual" shoulder dimensions and the other broader studies; i.e., not upon any multivariate manipulation, but upon the inclusion in the broader study of a wider range of information about the shape of the primate shoulder. Knowledge of these and other points is important in assessing the overall contribution of the discussion of Corruccini and Ciochon.

Animals↗
PubMed1975

The place of the australopithecines in human evolution: grounds for doubt?

Although most studies emphasise the similarity of the australopithecines to modern man, and suggest, therefore, that these creatures were bipedal tool-makers at least one form of which (Australopithecus africanus--"Homo habilis", "Homo africanus") was almost directly ancestral to man, a series of multivariate statistical studies of various postcranial fragments suggests other conclusions. Their locomotion may not have been like that of modern man, and may, though including a form or forms of bipedality, have been different enough to allow marked abilities for climbing. Bipedality may have arisen more than once, the Australopithecinae displaying one or more experiments in bipedality that failed. The genus Homo may, in fact, be so ancient as to parallel entirely the genus Australopithecus thus denying the latter a direct place in the human lineage.

Animals↗