When it comes to studying organisms, having size independent measures for maturity are important for many aspects of organismal biology, and may be crucial for determining taxonomic affinity, and morphological signals associated with ontogenetic age (i.e., juvenile vs. adult) and sexual dimorphism. This is because the size of an organism can be the result of many factors that are not necessarily indicators of maturity (Chabreck and Joanen, 1979; Ferguson, 1984; Mazzotti et al., 1986; Deeming and Ferguson, 1989; Brandt, 1991). This problem is particularly pronounced when researchers are studying extinct species. The purpose of my research project was to investigate and understand patterns of morphological variation in the phytosaur premaxilla and maxilla and to determine the degree to which morphological variation is a result of ontogeny. For example, such patterns might include the number, size and location of alveoli or the presence of prenarial crests. I conducted this research by gathering information on the premaxilla and maxilla of all phytosaur elements present in the University of Texas at Austin Vertebrate Paleontology Lab collection. I then performed statistical analysis on the data, and compared my results to those of previous authors to see if I could identify any ontogenetic signal. I did not identify size-independent ontogenetic influence on morphology with certainty but I did find some possible features that merit additional investigation in future studies. Those include the presence of one to three diastemas located primarily at the anterior end of the premaxilla, a wide interpremaxillary fossa but small alveolar ridge, and alveoli whose size mirror the width of the premaxilla (for example wide areas in the premaxilla are associated with larger alveoli whereas narrow areas in the premaxilla are associated with smaller alveoli). My study also confirmed the previous findings of Hungerbühler (2002) that the alveoli of phytosaurs are heterodont and exist in three distinct location-specific patterns, and the work of other researchers that prenarial crests are present only in larger specimens (Camp, 1930; Ballew, 1986; Hungerbühler, 2002; Stocker, 2010). / text

In most folivorans, the premaxilla is loosely attached to the maxilla, so that it is often missing in otherwise very well-preserved fossil skulls. Despite its infrequent preservation in sloths, the premaxilla has been shown to have phylogenetically significant variation among the taxa that do preserve the element. In the family Megalonychidae, the premaxilla is known only in the early taxon Eucholoeops (Santacrucian South American Land Mammal Age [SALMA]), the extant two-toed sloth Choloepus, and the North American Neogene taxon Megalonyx, the last described only in an unpublished Master’s thesis. We report here the discovery of the premaxilla in two genera of extinct megalonychids, Neocnus and Acratocnus. These small bodied, semiarboreal megalonychid sloths are endemic to the islands of the Greater Antilles. Though the presence of sloths in the Caribbean dates at least to the late Oligocene, the best known taxa derive from Pleistocene to Holocene cave deposits in Puerto Rico, Hispaniola, and Cuba. We also describe the premaxilla in two species of Megalonyx from North America, the Blancan North American Land Mammal Age (NALMA) M. leptostomus and Rancholabrean NALMA M. jeffersonii. These species show a progressive reorientation of the premaxilla within Megalonyx from a primitive horizontal element to a nearly vertical element, and some significant changes in the anatomy of the incisive foramen. Morphological evidence suggests that a broadened, plate-like premaxilla constitutes a synapomorphy for the entire clade Megalonychidae. Furthermore, although Eucholoeops retains a short anterior process of the premaxilla like that of megatherioid sloths, this process is lacking in the other megalonychids, suggesting that the loss of this process may unite late Miocene to Recent megalonychids.

No description available.

Variation in the shape and position of the internal nasal floor relative to the lower border of the piriform aperture in the genus Homo has been described as having three primary shape configurations: level, sloped, or depressed. The high frequency of depressed nasal floors among Neandertals relative to other fossil and extant groups (>80%) had originally led to the idea that nasal floor depression was related to an overall enlarged nasal capsule - an adaptive feature that would have been under selection among Neandertals living in cold, glacial climates. For a variety of reasons, subsequent research has found little empirical or theoretical support for this adaptive idea. Recent research on extant humans has also demonstrated that nasal floor shape variation, unlike many other midfacial traits, does not arise until well after birth, with nasal floor depression (when it occurs) appearing at the earliest around 3.0 years of age. Furthermore, nasal floor depression was also shown to correspond with a vertically expanded premaxillary region. Thus, it was hypothesized that nasal floor depression might be related to variation in key developmental and morphological aspects of the anterior maxillary dentition. This study metrically quantifies nasal floor topography for the first time in order to more objectively examine patterns of shape variation and to test explicit hypotheses regarding potential causative factors for nasal floor variation. The variables examined include anterior tooth dimensions, dental developmental rate, aspects of midfacial shape, overall facial size, and patterns of premaxillary/post-maxillary integration. It was found that among these, only dental developmental rate was clearly correlated with internal nasal floor shape. This result indicates that aspects of anterior dental development may indeed be a causative factor in the development of nasal floor shape variation. The existing visual discrete coding system for nasal floor topography was also evaluated in light of the new, quantitative data produced by this study as well as a critical comparison of the consistency of nasal floor topography definitions used previously in the literature. While it is suggested that quantitative data are preferable to qualitative data for this trait when possible, limitations in research methods for collecting quantitative data on osteological and fossil collections remain difficult to overcome. Thus a new, two-category presence/absence based system for describing nasal floor shape is proposed.

Introdução: A pré-maxila, em pacientes com fissura labiopalatina completa bilateral, possui morfologia, tamanho e mobilidade variáveis e, inicialmente, encontra-se projetada em direção anterior e com frequente desvio lateral, porém esse prognatismo é reduzido ao longo do processo reabilitador com as cirurgias primárias realizadas na infância, em especial a queiloplastia, revelando sua vulnerabilidade diante das cirurgias reparadoras. Objetivo: Este trabalho teve por objetivo avaliar e mensurar, em modelos digitais e tomografias computadorizadas, a inclinação da prémaxila e dos incisivos centrais superiores em pacientes com fissura completa bilateral de lábio e palato submetidos à queiloplastia e palatoplastia, no intuito de determinar características comuns a esses pacientes, verificar se existe correlação entre a inclinação da pré-maxila e dos incisivos centrais e comparar com um grupo controle. Material e Métodos: Foram analisados três grupos de pacientes. O grupo A foi composto por 79 pacientes com FBCLP sem tratamento ortodontico (idade média de 8.9 anos); O grupo B foi composto por 10 pacientes com FBCLP e tratamento ortodôntico finalizado (idade média de 23.1 anos); e o grupo C (controle) foi composto por 23 pacientes sem fissura e com equilíbrio das bases ósseas maxilar e mandibular. Nas imagens de tomografias computadorizadas foram mensuradas as inclinações dos incisivos centrais superiores e da pré-maxila por meio do Software Nemoscan (Nemotec, Madri, Espanha). Os modelos de gesso foram digitalizados pelo scanner 3Shape R700 3D e as inclinações dos incisivos centrais superiores foram mensuradas pelo Software OrthoAnalyserTM 3D. A análise estatística foi realizada de forma descritiva e por meio do teste Coeficiente de Correlação de Pearson. Para a comparação intergrupos foi utilizado a análise de variância (ANOVA) e o teste Tukey. Resultados: Foram encontradas diferenças estatísticamente significantes entre os grupos A e B e entre os grupos A e C quando avaliada a inclinação dos incisivos. Quando comparados os grupos B e C não observou-se diferença estatísticamente significante. Houve uma boa correlação entre as inclinações dos incisivos e da pré-maxila, com excessão para o grupo B. Os incisivos e a pré-maxila no grupo A apresentaram inclinações acentuadamente lingualizadas. Conclusões: A FBCLP causa uma grande interferência negativa na posição dos incisivos centrais superiores e na pré-maxila. E mesmo naqueles pacientes que foram tratados ortodônticamente as inclinações continuam sendo mais verticalizadas que as de indivíduos sem fissura. A pré-maxila não consegue acompanhar na totalidade a correção da inclinação dos incisivos após o tratamento ortodôntico. / Introduction: The premaxilla in patients with complete bilateral cleft lip and palate, has a variable morphology, size and mobility and initially is projected anteriorly and with frequent lateral deviation, but this prognathism is reduced along with the rehabilitative process and with primary surgeries performed in childhood, especially the lip repair, revealing its vulnerability of reconstructive surgeries. Objective: This study aimed to evaluate and measure in digital models and CT scans, the inclination of the premaxilla and maxillary central incisors in patients with bilateral complete cleft lip and palate that underwent lip repair and palatoplasty in order to determine ordinary characteristics to these patients, check whether there is a correlation between the inclination of the pre-maxilla and the central incisors as compared with a control group. Material and Methods: Three groups of patients were analyzed. Group A comprised 79 patients with FCBLP without orthodontic treatment (mean age of 8.9 years); Group B comprised 10 patients with FBCLP and finished orthodontic treatment (mean age of 23.1 years); and group C (control) included 23 patients without cleft and balance of mandibular and maxillar bone bases. In the images of CT scans the inclinations of maxillary central incisor and premaxilla through Software Nemoscan (Nemotec, Madrid, Spain) were measured. The plaster models were scanned by 3Shape R700 3D scanner and the inclination of maxillary central incisors were measured by 3D Software OrthoAnalyserTM. Statistical analysis was performed descriptively and by means of Pearson\'s correlation coefficient test. For comparison between groups, it was used analysis of variance (ANOVA) and Tukey test. Results: Statistically significant differences were found between A and B groups and between A and C groups when the inclination of the incisors were measured. No statistically significant difference was found between B and C groups. There was a good correlation between the inclinations of the ncisors and the premaxilla, with exception for group B. The incisor and premaxilla in group A showed markedly lingual inclinations. Conclusions: The FBCLP cause a large negative interference in the position o f the maxillary central incisors and the premaxilla. And even in those patients treated orthodontically, the inclinations remained more verticalized than the ones of individuals without cleft. The premaxilla is unable to follow the full correction of the incisors inclination after orthodontic treatment.

Introdução: A pré-maxila, em pacientes com fissura labiopalatina completa bilateral, possui morfologia, tamanho e mobilidade variáveis e, inicialmente, encontra-se projetada em direção anterior e com frequente desvio lateral, porém esse prognatismo é reduzido ao longo do processo reabilitador com as cirurgias primárias realizadas na infância, em especial a queiloplastia, revelando sua vulnerabilidade diante das cirurgias reparadoras. Objetivo: Este trabalho teve por objetivo avaliar e mensurar, em modelos digitais e tomografias computadorizadas, a inclinação da prémaxila e dos incisivos centrais superiores em pacientes com fissura completa bilateral de lábio e palato submetidos à queiloplastia e palatoplastia, no intuito de determinar características comuns a esses pacientes, verificar se existe correlação entre a inclinação da pré-maxila e dos incisivos centrais e comparar com um grupo controle. Material e Métodos: Foram analisados três grupos de pacientes. O grupo A foi composto por 79 pacientes com FBCLP sem tratamento ortodontico (idade média de 8.9 anos); O grupo B foi composto por 10 pacientes com FBCLP e tratamento ortodôntico finalizado (idade média de 23.1 anos); e o grupo C (controle) foi composto por 23 pacientes sem fissura e com equilíbrio das bases ósseas maxilar e mandibular. Nas imagens de tomografias computadorizadas foram mensuradas as inclinações dos incisivos centrais superiores e da pré-maxila por meio do Software Nemoscan (Nemotec, Madri, Espanha). Os modelos de gesso foram digitalizados pelo scanner 3Shape R700 3D e as inclinações dos incisivos centrais superiores foram mensuradas pelo Software OrthoAnalyserTM 3D. A análise estatística foi realizada de forma descritiva e por meio do teste Coeficiente de Correlação de Pearson. Para a comparação intergrupos foi utilizado a análise de variância (ANOVA) e o teste Tukey. Resultados: Foram encontradas diferenças estatísticamente significantes entre os grupos A e B e entre os grupos A e C quando avaliada a inclinação dos incisivos. Quando comparados os grupos B e C não observou-se diferença estatísticamente significante. Houve uma boa correlação entre as inclinações dos incisivos e da pré-maxila, com excessão para o grupo B. Os incisivos e a pré-maxila no grupo A apresentaram inclinações acentuadamente lingualizadas. Conclusões: A FBCLP causa uma grande interferência negativa na posição dos incisivos centrais superiores e na pré-maxila. E mesmo naqueles pacientes que foram tratados ortodônticamente as inclinações continuam sendo mais verticalizadas que as de indivíduos sem fissura. A pré-maxila não consegue acompanhar na totalidade a correção da inclinação dos incisivos após o tratamento ortodôntico. / Introduction: The premaxilla in patients with complete bilateral cleft lip and palate, has a variable morphology, size and mobility and initially is projected anteriorly and with frequent lateral deviation, but this prognathism is reduced along with the rehabilitative process and with primary surgeries performed in childhood, especially the lip repair, revealing its vulnerability of reconstructive surgeries. Objective: This study aimed to evaluate and measure in digital models and CT scans, the inclination of the premaxilla and maxillary central incisors in patients with bilateral complete cleft lip and palate that underwent lip repair and palatoplasty in order to determine ordinary characteristics to these patients, check whether there is a correlation between the inclination of the pre-maxilla and the central incisors as compared with a control group. Material and Methods: Three groups of patients were analyzed. Group A comprised 79 patients with FCBLP without orthodontic treatment (mean age of 8.9 years); Group B comprised 10 patients with FBCLP and finished orthodontic treatment (mean age of 23.1 years); and group C (control) included 23 patients without cleft and balance of mandibular and maxillar bone bases. In the images of CT scans the inclinations of maxillary central incisor and premaxilla through Software Nemoscan (Nemotec, Madrid, Spain) were measured. The plaster models were scanned by 3Shape R700 3D scanner and the inclination of maxillary central incisors were measured by 3D Software OrthoAnalyserTM. Statistical analysis was performed descriptively and by means of Pearson\'s correlation coefficient test. For comparison between groups, it was used analysis of variance (ANOVA) and Tukey test. Results: Statistically significant differences were found between A and B groups and between A and C groups when the inclination of the incisors were measured. No statistically significant difference was found between B and C groups. There was a good correlation between the inclinations of the ncisors and the premaxilla, with exception for group B. The incisor and premaxilla in group A showed markedly lingual inclinations. Conclusions: The FBCLP cause a large negative interference in the position o f the maxillary central incisors and the premaxilla. And even in those patients treated orthodontically, the inclinations remained more verticalized than the ones of individuals without cleft. The premaxilla is unable to follow the full correction of the incisors inclination after orthodontic treatment.