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R S Corruccini

Publications and source records attributed to R S Corruccini.

At least 55 records · Page 3Linked to original sources
PubMed1981

Variance of occlusion traits in twins.

To reexamine the prevailing concepts of the role of genetic and environmental factors on dental occlusion, individual occlusal traits were studied in 164 pairs of twins. The measured variables were overjet, overbite, crossbite type and extent, buccal segment relationship type and extent, anterior and posterior teeth malalignment, spacing, treatment priority index scores, and the principal components derived from these measures. No association of twin type with the mean of any of the traits could be demonstrated. Further analysis of variance revealed separate sources of twin variance for the set of occlusal variables studied. We were able to detect a significant genetic source of variation for overbite and spacing, and no variance inequality between monozygotic and dizygotic twins. For the majority of the trains (overjet, crossbite, buccal segment relationship, malalignment, and treatment priority index scores), tests of homogeneity of total variance showed inequality between zygosities. The total among-pair and within-pair mean squares were larger for dizygotic than for monozygotic twins. We interpreted the results as evidence for greater environmental influences on the two types of twins. In addition, environmental covariance appeared to be larger for monozygotic than for dizygotic twins with respect to crossbite. In cases where within-pair genetic variance estimates were highly significant, removing the bias due to unequal environmental effects on the two types of twins led to results of no significant genetic variance. These results indicate a further need to explore the sources of environmental variation contributing to the difference. Genetic models that may be used to gain insights into the sources are discussed.

Adolescent↗
PubMed1980

Genetic analysis of occlusal variation in twins.

Orthodontists usually assume that genetic factors are of major significance to the development of malocclusion. Studies of twin similarities have lent support to this concept. Use of the twin model to estimate genetic variance, however, involves the assumptions that there are no mean or total variance inequalities between monozygotic and dizygotic twins. The environmental (including biologic) differences between monozygotic and dizygotic twin development may therefore constitute a source of bias. Genetic variance and heritability were estimated for a series of arch and occlusal traits in sixty twins using recently developed methods that are unbiased by variance heterogeneity between zygosities. Heterogeneity was demonstrated for twenty of the forty traits, suggesting considerable amounts of hidden environmental determinance. Tooth-displacement means differed between monozygotes and dizygotes, indicating bias in that trait's genetic variance analysis. Significant heritability could not be demonstrated for overbite, overjet, buccal segment relation, total tooth displacement, and occlusal discrepancies in arch shape. Arch size, individual tooth displacement scores, and cross-bite show significant genetic variance, averaging only about 36 percent of the total variance of these traits.

Adolescent↗
PubMed1980

Size and positioning of the teeth and infratemporal fossa relative to taxonomic and dietary variation in primates.

The infratemporal fossa grows allomorphically in primates at a faster rate than general cranial and inferred body size. The coefficient of allometry approximates 1.5 across most primate groups, suggesting direct scaling of the muscsulus temporalis cross-sectional area to body mass. This coefficient is larger than 1.5 in Lorisoidea and Ceboidea. Mediolateral relative growth of the infratemporal passage that accommodates m. temporalis rather than antero-posterior growth absorbs a disproportionate amount of this expansion. Likewise, infratemporal fossa breath is positively allometric to tooth size, especially in insectivorous, frugivorous and folivorous primate samples that are homogeneous with respect tok diet. The seemingly growth-related positive relations between tooth size and distal placement of the zygomatic root that is consistent over the cumulative sample is erased by controlling for diet. Increased relative amounts of m. temporalis per unit of dental occlusal area is indicated in larger-bodied forms; increasing crown height may be a mechanism to adjust for this.

Animals↗
PubMed1980

Miocene hominoid palatofacial morphology.

The palatofacial morphology of Proconsul africanus, P. nyanzae, P. major and Sivapithecus meteai is compared to extant catarrhines. The early Miocene hominoids (Proconsul) are unlike modern great apes, but retain a primitive catarrhine pattern more similar to some extant cercopthecoids. By middle Miocene times the typical hominoid palatofacial morphology can be recognized in at least one species (S. meteai) and this corresponds to the evolution of the postcranium in which the hominoid pattern is also only recognizable by the middle Miocene.

Animals↗
PubMed1979

Primate facial allometry and interpretations of australopithecine variation.

Pilbeam and Gould have discussed African Plio-Pleistocene hominid evolution in the context of allometry (size-dependent morphological change). These authors demonstrate that some general aspects of australopithecine morphology (tooth, brain and body size) support the hypothesis that certain early African hominids were merely scaled variations of each other at different sizes. They also speculate that the methods applied to these very broad anatomical categories can be extended to more specific and detailed traits, especially in the face and cranium. Such traits underlie most taxonomic and phylogenetic discussions of the early African Hominidae, so it is useful to follow Pilbeam and Gould's lead, as we do here, and investigate the structural differences in the australopithecine face and cranimum in a quantificiable fashion.

Africa↗
PubMed1979

Morphological affinities of Pan paniscus.

Although the pygmy chimpanzee (Pan paniscus) is more similar to man than is the common chimpanzee (Pan troglodytes) in some traits, the resemblance is due primarily to the smaller size and concomitant allometric generalization of the former. The two species of chimpanzees are equally good models for the common ancestry of African apes and man.

Animals↗
PubMed1979

Determination of sex by discriminant function analysis of postcranial skeletal measurements.

Thieme and Schull [16] took measurements of seven postcranial traits from black skeletons of known sex to devise a method for accurately sexing human remains. With a linear discriminant function analysis of the data they obtained a 98.5% accuracy. The research reported here was designed to assess the accuracy of their method in the hands of other investigators using a sample of the same black population and its applicability to other populations of the same and different races. None of the samples used in this study were sexed with the same rate of accuracy either achieved or predicted by Thieme and Schull. However, two samples did reach 91% or better. Such results suggest that the methods employed have considerable value if used with appropriate precautions. Our multiple discriminant function analysis strongly indicates that neither side nor observer techniques affected the results. Sex accounts for a predominant fraction of the total variation among samples and race accounts for most of that remaining.

Anthropometry↗
PubMed1978

Multivariate dental allometry in primates.

Disagreement is current over the question of whether relatively large teeth in some large primates are a natural outcome of growth trends instead of an indication of intrinsic differences. A cross-primate survey of dental scaling relative to skull (and inferred body) size is given in this study, using a principal component technique to measure the multivariate growth relation between two sets of data: dental size and cranial size. Cheek teeth are strongly positively allometric in restriced taxonomic groups, especially in cercopithecoids. Conversely, the allometry drops to an almost linear proportional growth relation when variation in diet is controlled.

Animals↗
PubMed1978

Analysis of the hominoid os coxae by Cartesian coordinates.

This study is based upon 48 3-dimensional coordinates taken on 4 fossil hominid and 127 extant hominoid coxal bones. The follis include Sts 14, SK 3155, MLD 7, and MLD 25. The comparative sample consists of 42 Homo sapiens, 27 Pan troglodytes, 29 Gorilla gorilla and 29 Pongo pygmaeus. The coordinates improve the metrical representation of the bone beyond what can be done with linear measurements because the shape complexity of the os coxae is so great. The coordinates are rotated and translated so that all bones are in a standard position. The coordinates are then standardized for each specimen by dividing all coordinates by the pooled standard deviation of X, Y, and Z coordinates. These data are treated to standard statistical analyses including analysis of variance, Penrose size and shape statistics, principal coordinates and components, and canonical variates analysis. The data are then further altered by using some specimen as a standard and rotating each specimen until the total squared distance between its coordinates and those of the standard are minimized. The same statistics are applied to these "best fit" data. The results show a high degree of agreement between the methods. The hominid os coxae are dundamentally different from the other hominoids and the fossil hominids share the basic hominid configuration but with some unique differences.

Animals↗
PubMed1978

Morphoclinal variation in the anthropoid shoulder.

A morphocline in the organization of the shoulder joint is demonstrated among anthropoid primates. This metrical test supports the view that hominoid distinctions are monophyletic in origin. The primates that are behaviorally and functionally convergent on hominoids are only partially convergent or are not convergent in shoulder morphology.

Animals↗
PubMed1978

Relative femoral head size in early hominids.

Relative growth of the human femur head is studied by a logarithmic principal components method. Growth rates differ according to the population sampled and the other body dimensions being compared, and especially according to sex. The results do not support biomechanical assumptions of strongly positive allometry of the femur head, which have been used to argue that the australopithecine hip joint was not relatively small.

Animals↗
PubMed1978

The femur in early human evolution.

Uni- and multivariate analyses of 5 fossil and 215 extant hominoid femora show that two morphological patterns of hominid femora existed about two million years ago. Femora classified as Homo sp. indet. (KNMER 1472 and 1481) are more like Homo sapiens although not identical. Those classified as Australopithecus robustus (SK 82 and 97) and A. boisei (KNM-ER 1503) are similar to one another but uniquely different from any living hominoid. The strong mophological constrasts imply biomechanical and possible locomotor differences, although these are as yet unknown.

Animals↗
PubMed1977

Features of the prosimian wrist joint in relation to hominoid specializations.

The wrist joint of lemuroid and lorisoid prosimians is examined in relation to variations among higher primates, particularly the specializations characteristic of hominoids. The lorisines Nycticebus and Perodicticus share a metrically defined primitive morphopattern with other prosimians and cercopithecine monkeys, showing little convergence on apes in carpal bone and distal radius and ulna shape.

Anatomy, Comparative↗