Marisol Anzelmo

Ontogenetic changes in cranial vault thickness in a modern sample of Homo sapiens.

This work assesses cranial vault thickness (CVT) ontogenetic changes using a computed tomography database to register thickness across multiple regions.

Measurement error of 3D cranial landmarks of an ontogenetic sample using Computed Tomography

BACKGROUND/AIM Computed Tomography (CT) is a powerful tool in craniofacial research that focuses on morphological variation. In this field, an ontogenetic approach has been taken to study the developmental sources of variation and to understand the basis of morphological evolution. This work aimed to determine measurement error (ME) in cranial CT in diverse developmental stages and to characterize how this error relates to different types of landmarks. MATERIAL AND METHODS We used a sample of fifteen skulls ranging from 0 to 31 years. Two observers placed landmarks in each image three times. Measurement error was assessed before and after Generalized Procrustes Analysis. RESULTS The results indicated that ME is larger in neurocranial structures, which are described mainly by type III landmarks and semilandmarks. In addition, adult and infant specimens showed the same level of ME. These results are specially relevant in the context of craniofacial growth research. CONCLUSION CT images have become a frequent evidence to study cranial variation. Evaluation of ME gives insight into the potential source of error in interpreting results. Neural structures present higher ME which is mainly associated to landmark localization. However, this error is irrespective of age. If landmarks are correctly selected, they can be analyzed with the same level of reliability in adults and subadults.

Developmental covariation of human vault and base throughout postnatal ontogeny

In the present study, we analyzed postnatal ontogenetic integration among morphological traits of the human neurocranium. Particularly, the covariation between the vault and the base during postnatal life was assessed. Since the association between these regions may depend on the generalized change produced by allometry, we tested its effect on their covariation. On a sample of adults and subadults ranging from 0 to 31 years, 3D coordinates of neurocranial landmarks and semilandmarks were digitized and geometric morphometric technics were applied. Main aspects of shape variation were examined using Principal Components analysis. Covariation between the vault and the base was examined by Partial Least Squares analysis. According to our results, the vault and the base covary strongly during postnatal ontogeny and their relation depends largely on allometry. Two size variables were studied: centroid size, which was obtained from the recorded morphometric points, and endocranial volume, taken as an estimation of brain size. Although growing brain was found to be a developmental process that contributes to covariation among neurocranial traits, there would be other factors that exert their influence during ontogeny. These results lead to reconsider cranial morphological evolution taking into account the developmental constraints given by ontogenetic patterns of integration and reinforcing the idea that in human evolution a suite of relevant characters may be fuelled by few developmental processes.

Morphological Integration of the Orbital Region in a Human Ontogenetic Sample

Most studies on craniofacial morphology have focused on adult individuals, but patterns of variation are the outcome of genetic and epigenetic variables that interact throughout ontogeny. Among cranial regions, the orbits exhibit morphological variation and occupy an intermediate position between neurocranial and facial structures. The main objective of this work was to analyze postnatal ontogenetic variation and covariation in the morphology of the orbital region in a cross‐sectional series of humans from 0 to 31 years old. Landmarks and semilandmarks were digitized on the orbital rim, as well as in neighboring neural and facial structures. Data were analyzed using geometric morphometrics. Results indicated that orbital size increases during the first years of postnatal life, while the shape of the orbital aperture does not change significantly with age. In general, the pattern and magnitude of shape covariation do not vary markedly during postnatal life although some subtle shifts were documented. Additionally, the shape of the orbital aperture is more related to the anterior neurocranium than to zygomatic structures, even when the allometry is adjusted. Although we expected some influence from postnatal craniofacial growth and from some functional factors, such as mastication, on the development of the orbits, this assumption was not completely supported by our results. As a whole, our findings are in line with the prediction of an early influence of the eyes and extraocular tissues on orbital morphology, and could be interpreted in relation to processes promoting early neural development that coordinately affects orbital traits and the neurocranial skeleton. Anat Rec, 299:70–80, 2016.

Ontogenetic Patterns of Morphological Variation in the Ectocranial Human Vault

The skull is considered a modular structure in which different parts are influenced by different factors and, as a result, achieve adult shape at different ages. Previous studies have suggested that the basicranium presents a modular pattern that distinguishes sagittal and lateral parts, probably affected by the brain and masticatory structures, respectively. The vault of modern humans, in contrast, has been considered as a highly integrated system mainly influenced by brain growth. Here, we explored developmental shape variation in sagittal and lateral ectocranial vault in humans in order to assess if both regions are ontogenetically dissociated. We used a sample of 135 cranial computed tomography images from 0 to 31 ages. Landmarks and semilandmarks were collected on sagittal and lateral regions and geometric morphometric techniques were applied separately for each region. On the shape coordinates, we used Goodalls F‐test in order to assess the age when the adult configuration is attained. Principal component analysis enabled us to evaluate shape variation during ontogeny. Results indicated that both sagittal and lateral structures attain adult shape at early adolescence. Both regions express coordinated shape modifications probably due to shared developmental factors. It is concluded that masticatory muscles may not exert a strong enough influence to produce independent variation in the lateral traits. Thus, it is likely that the brain integrates sagittal and lateral parts of the vault across human ontogeny. Anat Rec, 296:1008–1015, 2013.

Envejecimiento, pérdida dentaria y cambios craneofaciales/Aging, tooth loss and craneofacial changes

RESUMEN Este trabajo se centra en el analisis de cambios osteoartrosicos observados en esqueletos del cementerio de Rincon Chico 21 (Santa Maria, Catamarca), con el objeto de intentar la reconstruccion de los habitos corporales mas probables y explorar su vinculacion con eventuales divisiones del trabajo en la poblacion que genero este cementerio precolombino. Las manifestaciones osteoartrosicas en los principales sistemas articulares de 56 individuos adultos de ambos sexos fueron registradas, analizadas y comparadas. Los resultados sugieren que en esta comunidad con una economia de subsistencia principalmente basada en la practica de agricultura de regadio y pastoreo de camelidos (Desarrollos Regionales), habria existido una division de tareas y/o actividades potencialmente relacionadas con el sexo de los individuos. Asimismo, los analisis estadisticos aplicados entre los grupos etarios considerados estarian indicando que la edad constituiria un factor determinante en la expresion final de la enfermedad degenerativa articular tanto en las articulaciones de los miembros inferiores como en las del esqueleto axial. ABSTRACT This research is centered on the skeletal analysis of osteoarthritic changes observed in individuals from Rincon Chico 21, a prehistoric burial site at Santa Maria, Catamarca, Argentina. The aim was to try the reconstruction of the most probable corporal behaviours, as well as the possible relationships with labour divisions among individuals from the population that generated the prehistoric cemetery. Osteoarthritic manifestations on the main articular systems of 56 systematically excavated adult skeletons of both sexes were registered, analyzed and compared. Results suggested that in this prehistoric community, with subsistence economy based on agriculture and pastoralism (Regional Developments Period), there may have existed a sexual division of the daily activities. In addition, the results of the statistical analysis applied among the age groups indicate that the age would be an important factor for determining the final expression of the degenerative joint disease, both in the joints of the lower extremities and in the axial skeleton.RESUMEN El estudio de las poblaciones humanas antiguas es complejo y requiere de un enfoque interdisciplinario. La arqueologia argentina esta promoviendo el desarrollo de nuevas lineas de evidencias que incluyen espacios muy activos de interaccion con la biologia. Numerosos estudios biologicos se efectuan sobre los depositos sedimentarios asociados al contexto arqueologico. Los sedimentos asociados a los restos humanos constituyen un recurso de informacion poco explorado y en general, escasamente contemplado en el diseno previo de la excavacion. El presente trabajo aborda el examen de sedimentos de foramenes sacrales de esqueletos humanos pertenecientes al Museo Regional Monsenor Fagnano, Tierra del Fuego, una clase de material arqueologico poco estudiado. La recuperacion de rotiferos, artropodos y parasitos justifica el esfuerzo de muestreo sobre materiales sin asignacion temporal y con escasa referencia espacial. Se puede concluir que el estudio de microfosiles presentes en este tipo de deposito permite maximizar la informacion obtenida del registro bioarqueologico debido a que albergan valiosa informacion paleoambiental, bioantropologica y tafonomica. Asi, el estudio exhaustivo y no destructivo de las muestras arqueologicas resulta un punto crucial en la estrategia de investigacion. ABSTRACT The study of ancient human populations is complex and requires an interdisciplinary approach. The Argentinean archaeology is promoting the development of new research fields, including areas of active interaction with biology. Numerous biological studies are conducted on the sedimentary deposits in association to the archaeological context. The sediments associated to human remains constitute an unexplored source of information. Nevertheless, this material is frequently overlook during excavations and/or insufficient number of samples are taken. The present study analyzes the sediments found in sacral foramina of human skeletons belonging to the Monsenor Fagnano Regional Museum, Tierra del Fuego this is a kind of archaeological material rarely studied. The recovery of rotifers, arthropods and parasites justified the sampling effort on this unusual sediments characterized by a low temporary and spatial reference. It can be concluded that the study of microfossils found in this type of deposit maximized the information obtained from the bioarchaeological registry because it harbors valuable palaeoenvironmental, bioanthropological and taphonomic data. Therefore, the exhaustive and non-destructive study of the archaeological samples is a crucial point in the research strategy

Frontal sinus ontogeny and covariation with bone structures in a modern human population

In humans, the frontal sinus (FS) is located in the medial part of the supraorbital region, sometimes expanded throughout the frontal squama. It exhibits high morphological variability, but its general form appears to be constrained by surrounding structures. The goal of this study is to analyze FS growth and test for covariation between FS volume and the glabellar region, upper nasal region, bone thickness and endocranial size in a human sample from Argentina. The sample comprises 149 reconstructions derived from computed tomography images of individuals aged 0–31 years. Volume of the FS and measurements of the surrounding structures were recorded. The FS growth trajectory was assessed by parametric and nonparametric methods, and covariation was determined using correlations and partial correlations. The FS volume could be measured at an age of about 6 years and older; adults had no aplasia but hyperplasia was found in some cases. Since the most conspicuous characteristic found was variation among individuals, the nonparametric smoothing spline produced very poor fitting. The modified logistic function was the only parametric method providing significant parameters. Sexes differed in the age at which FS growth began and ended, with FS developing earlier but at a slower rate in females than in males. The FS volume did not correlate with either upper nasal width or endocranial volume, but it correlated with bone thickness measurements (mainly from the glabellar region), even when age was held constant. Expansion of the FS at the frontal poles also correlated with frontal bone thickness. Despite the difficulty in modeling and predicting the trajectory and morphology of FS, our results suggest that it is affected by its surrounding bony environment.

Complex pattern of variation in neurocranial ontogeny revealed by CT-scanning

ABSTRACT The neurocranium of hominid species has been largely studied with reference to the midsagittal plane, with variations being attributed to brain evolution. By contrast, there is limited information on variation in non-midsagittal regions, which are the points of insertion of muscles and bony structures related to mastication. This work aims to analyze ontogenetic changes and sexual dimorphism (SD) in midsagittal and non-midsagittal neurocranial structures from a contemporary human sample comprising 138 computed tomography (CT) cranial images of individuals ranging from infants to adults. Morphology of the vault and the base was assessed by registering landmarks and semilandmarks, which were analyzed by geometric morphometrics, and the endocranial volume (EV). The results of regressions and Kruskal-Wallis test indicate that the major size and shape changes in both midsagittal and non-midsagittal regions occur during infancy and juvenility; shape changes are also associated with an increase in EV. The size of the midsagittal vault, the shape of the non-midsagittal vault and the size of the base show an extension of ontogenetic trajectories. Sexes show similar changes in shape but different changes in size. We conclude that brain growth appears to be an important factor influencing the morphology of the neurocranium, at least during infancy and childhood. Subsequent changes may be attributed to osteogenic activity and the differential growth of the brain lobes. Masticatory-related bony structures and muscles may not be strong enough factors to induce independent modifications in non-midsagittal structures. The small influence of the cranial muscles would explain why the human neurocranium is a quite integrated structure.

Alometrías ontogénicas y dimorfismo sexual facial en dos poblaciones humanas modernas/Ontogenetic allometry and facial sexual dimorphism in two modern human populations

espanolLa teoria evolutiva interpreta el comportamiento humano como adaptativo, es decir, contribuye a maximizar el exito reproductivo de quien lo exhibe. Sin embargo, debido a que la reproduccion implica un costo, aquellos comportamientos que permitan maximizar la relacion entre la produccion de descendientes y la inversion parental serian favorecidos por efecto de la seleccion natural. No obstante, esta relacion estara determinada por las limitaciones impuestas por el ambiente. Por otro lado, la teoria clasica de la transicion demografica sostiene que las mejoras en las condiciones de vida de una poblacion determinan un descenso de la fecundidad. ?Podemos explicar esta relacion desde un punto de vista evolutivo? La poblacion Toba Cacique Sombrero Negro se encuentra en plena transicion economica y social, caracterizada por un mayor sedentarismo y una incipiente economia de mercado. En este trabajo se estiman la Tasa Global de Fecundidad (TGF) y la tasa especifica por edades (fx) de la poblacion rural Toba del oeste de la provincia de Formosa, correspondientes a cuatro periodos entre 1981 y 1999. Se obtuvieron valores crecientes de la TGF que variaron entre 6.36 y 7.27 hijos. La fx evidencio importantes variaciones que determinaron un envejecimiento de las curvas en una primera etapa y un posterior rejuvenecimiento de esta. Se propone aqui que el aumento en la fecundidad estaria determinado por una disminucion de los costos reproductivos maternos, lo que seria el resultado de un mayor acceso a recursos energeticos. Sin embargo, los costos reproductivos pueden variar con la edad materna y por lo tanto, afectando a la estructura etaria de la fecundidad. EnglishAccording to the evolutionary theory, all behaviors should be considered adaptive, i.e., they help to maximize the reproductive success of this actor. However, reproduction involves a cost; thus, natural behaviors that maximize the relationship between the production of offspring and parental investment would be selected. However, this relationship is shaped by the environmental constraints. On the other hand, the classic theory of demographic transition argues that improvements in living conditions in a given population determine a decrease in fertility. Can this observation be explained in evolutionary terms? The population of aboriginal Toba in from Argentina is one undergoing a deep economic and social transition, characterized by a greater availability of material resources. The aim of this study was to evaluate the effect of these socioeconomic changes on several demographic parameters in a population of western Tobas from the province of Formosa, Argentina. This work estimated the Total Fertility Rate (TFR) and age-specific fertility rates (fx) of four periods between 1981-1999. Our results had shown increasing trends of TFR changing between 6.36 and 7.27 children. The peak of fertility changed first to older ages and then changed back to younger ages also. It is proposed that this increase in fertility would be determined by a decrease in maternal reproductive costs, which would be the result of increased access to energy resources. However, these costs can vary with maternal age, affecting the age structure of fertility.RESUMEN Se analizan las relaciones interpoblacionales y los roles relativos cumplidos por las fuerzas evolutivas en la diferenciacion biologica de un conjunto de poblaciones, que habitaron diversas regiones geografico-ecologicas del cono sur sudamericano, con especial atencion a aquellas que ocuparon la region central de Argentina. La muestra esta compuesta por 18 poblaciones, incluyendo 398 adultos masculinos, analizados en 10 variables craneofaciales. Se realizo el analisis de coordenadas principales a partir de distancias D 2 , asi como el analisis de Relethford y Blangero, basado en el modelo de Harpending y Ward para datos morfologicos. El analisis de distancias muestra a Cordoba en una posicion intermedia y relativamente diferenciada de las otras poblaciones, hecho consistente con su ubicacion geografica y que resalta ese factor como condicionante de la evolucion de la poblacion. Por otra parte, muestra similitudes con Santiago del Estero y marcadas diferencias con San Luis, la otra muestra poblacional de las Sierras Centrales. El analisis de Relethford-Blangero permite suponer para Cordoba un tamano efectivo poblacional relativamente grande y la existencia de alto flujo genico, con las poblaciones fuera de la region, mientras que la posicion de San Luis sugiere la accion de fuerzas aleatorias actuando sobre una poblacion pequena. ABSTRACT The aim of this paper is to analyze population relationships and the relative roles fulfilled by the evolutionary forces in the biological differentiation of a group of populations who lived in different geographic -ecological regions of the southern cone of South America, with particular emphasis on those that occupied the central region of Argentina. The sample consists of 18 populations , including 398 adult males , analyzed by ten craniofacial variables . P rincipal coordinates analysis based on D 2 distance and Relethford and Blangero analysis were carried out , based on the model of Harpending and Ward for morphological data. The distance analysis showed Cordoba in an intermediate position and relatively differentiated from the other populations , a fact consistent with its geographical location, that suggests that geography was a conditioning factor in the evolution of the population. On the other hand, Cordoba showed similarities with Santiago del Estero, but with marked differences with San Luis , the other population sample from the Sierras Centrales . The Relethford - Blangero analysis suggests for Cordoba, a relatively large effective population size and the existence of high gene flow with populations outside the region , while the position of San Luis suggests the action of random forces acting on a small isolated population. Publicado on-line: 29/07/2012El objetivo de este trabajo es evaluar el estado de salud oral de una muestra osteologica de origen arqueologico proveniente del sitio Esquina de Huajra, ocupado ca. 1400-1550 A.D. por una poblacion sedentaria y agricultora. Los indicadores considerados fueron el desgaste dental, la presencia de caries, enfermedad periodontal, abscesos y la perdida antemortem de piezas dentales. Se registro la presencia de cada uno de ellos en los 10 individuos que componen la muestra, tanto adultos como subadultos. Presentamos detalladamente la metodologia seguida, especialmente para el registro del desgaste dental. Los mas altos grados de desgaste se observaron en los molares, tal como se esperaria de piezas funcionalmente relacionadas con la masticacion de alimentos duros. Los resultados indicarian el consumo de alimentos ricos en carbohidratos y azucares sin restriccion etaria ni sexual. Tampoco se distinguieron grupos dentro de la muestra que pudieran haber tenido un consumo diferencial de alimentos. Esta homogeneidad concuerda con los resultados obtenidos a partir de los analisis de isotopos estables de C y N, asi como de los estudios del patron funerario.

Matrices funcionales e integración morfológica. Un estudio ontogénico de la bóveda y el maxilar/Functional matrices and morphological integration. An ontogenetic study on the vault and the maxilla

espanolLa teoria evolutiva interpreta el comportamiento humano como adaptativo, es decir, contribuye a maximizar el exito reproductivo de quien lo exhibe. Sin embargo, debido a que la reproduccion implica un costo, aquellos comportamientos que permitan maximizar la relacion entre la produccion de descendientes y la inversion parental serian favorecidos por efecto de la seleccion natural. No obstante, esta relacion estara determinada por las limitaciones impuestas por el ambiente. Por otro lado, la teoria clasica de la transicion demografica sostiene que las mejoras en las condiciones de vida de una poblacion determinan un descenso de la fecundidad. ?Podemos explicar esta relacion desde un punto de vista evolutivo? La poblacion Toba Cacique Sombrero Negro se encuentra en plena transicion economica y social, caracterizada por un mayor sedentarismo y una incipiente economia de mercado. En este trabajo se estiman la Tasa Global de Fecundidad (TGF) y la tasa especifica por edades (fx) de la poblacion rural Toba del oeste de la provincia de Formosa, correspondientes a cuatro periodos entre 1981 y 1999. Se obtuvieron valores crecientes de la TGF que variaron entre 6.36 y 7.27 hijos. La fx evidencio importantes variaciones que determinaron un envejecimiento de las curvas en una primera etapa y un posterior rejuvenecimiento de esta. Se propone aqui que el aumento en la fecundidad estaria determinado por una disminucion de los costos reproductivos maternos, lo que seria el resultado de un mayor acceso a recursos energeticos. Sin embargo, los costos reproductivos pueden variar con la edad materna y por lo tanto, afectando a la estructura etaria de la fecundidad. EnglishAccording to the evolutionary theory, all behaviors should be considered adaptive, i.e., they help to maximize the reproductive success of this actor. However, reproduction involves a cost; thus, natural behaviors that maximize the relationship between the production of offspring and parental investment would be selected. However, this relationship is shaped by the environmental constraints. On the other hand, the classic theory of demographic transition argues that improvements in living conditions in a given population determine a decrease in fertility. Can this observation be explained in evolutionary terms? The population of aboriginal Toba in from Argentina is one undergoing a deep economic and social transition, characterized by a greater availability of material resources. The aim of this study was to evaluate the effect of these socioeconomic changes on several demographic parameters in a population of western Tobas from the province of Formosa, Argentina. This work estimated the Total Fertility Rate (TFR) and age-specific fertility rates (fx) of four periods between 1981-1999. Our results had shown increasing trends of TFR changing between 6.36 and 7.27 children. The peak of fertility changed first to older ages and then changed back to younger ages also. It is proposed that this increase in fertility would be determined by a decrease in maternal reproductive costs, which would be the result of increased access to energy resources. However, these costs can vary with maternal age, affecting the age structure of fertility.RESUMEN Se analizan las relaciones interpoblacionales y los roles relativos cumplidos por las fuerzas evolutivas en la diferenciacion biologica de un conjunto de poblaciones, que habitaron diversas regiones geografico-ecologicas del cono sur sudamericano, con especial atencion a aquellas que ocuparon la region central de Argentina. La muestra esta compuesta por 18 poblaciones, incluyendo 398 adultos masculinos, analizados en 10 variables craneofaciales. Se realizo el analisis de coordenadas principales a partir de distancias D 2 , asi como el analisis de Relethford y Blangero, basado en el modelo de Harpending y Ward para datos morfologicos. El analisis de distancias muestra a Cordoba en una posicion intermedia y relativamente diferenciada de las otras poblaciones, hecho consistente con su ubicacion geografica y que resalta ese factor como condicionante de la evolucion de la poblacion. Por otra parte, muestra similitudes con Santiago del Estero y marcadas diferencias con San Luis, la otra muestra poblacional de las Sierras Centrales. El analisis de Relethford-Blangero permite suponer para Cordoba un tamano efectivo poblacional relativamente grande y la existencia de alto flujo genico, con las poblaciones fuera de la region, mientras que la posicion de San Luis sugiere la accion de fuerzas aleatorias actuando sobre una poblacion pequena. ABSTRACT The aim of this paper is to analyze population relationships and the relative roles fulfilled by the evolutionary forces in the biological differentiation of a group of populations who lived in different geographic -ecological regions of the southern cone of South America, with particular emphasis on those that occupied the central region of Argentina. The sample consists of 18 populations , including 398 adult males , analyzed by ten craniofacial variables . P rincipal coordinates analysis based on D 2 distance and Relethford and Blangero analysis were carried out , based on the model of Harpending and Ward for morphological data. The distance analysis showed Cordoba in an intermediate position and relatively differentiated from the other populations , a fact consistent with its geographical location, that suggests that geography was a conditioning factor in the evolution of the population. On the other hand, Cordoba showed similarities with Santiago del Estero, but with marked differences with San Luis , the other population sample from the Sierras Centrales . The Relethford - Blangero analysis suggests for Cordoba, a relatively large effective population size and the existence of high gene flow with populations outside the region , while the position of San Luis suggests the action of random forces acting on a small isolated population. Publicado on-line: 29/07/2012El objetivo de este trabajo es evaluar el estado de salud oral de una muestra osteologica de origen arqueologico proveniente del sitio Esquina de Huajra, ocupado ca. 1400-1550 A.D. por una poblacion sedentaria y agricultora. Los indicadores considerados fueron el desgaste dental, la presencia de caries, enfermedad periodontal, abscesos y la perdida antemortem de piezas dentales. Se registro la presencia de cada uno de ellos en los 10 individuos que componen la muestra, tanto adultos como subadultos. Presentamos detalladamente la metodologia seguida, especialmente para el registro del desgaste dental. Los mas altos grados de desgaste se observaron en los molares, tal como se esperaria de piezas funcionalmente relacionadas con la masticacion de alimentos duros. Los resultados indicarian el consumo de alimentos ricos en carbohidratos y azucares sin restriccion etaria ni sexual. Tampoco se distinguieron grupos dentro de la muestra que pudieran haber tenido un consumo diferencial de alimentos. Esta homogeneidad concuerda con los resultados obtenidos a partir de los analisis de isotopos estables de C y N, asi como de los estudios del patron funerario.