Spontaneous cleft palate in a newborn gorilla (Gorilla gorilla gorilla).

OBJECTIVE: We report the first case of cleft palate in a newborn male gorilla (Gorilla gorilla gorilla). CASE HISTORY AND RESULTS: The full-term infant was born to clinically healthy, wild-caught parents and survived 5 days. Autopsy disclosed a unilateral cleft palate, moderate scalp hemorrhage (birth versus postnatal trauma), cerebral edema, and a sterile fibrin vegetation in the heart. The palate was also shorter and narrower than expected, and the biorbital breadth was reduced; otherwise, growth and development appeared normal. Standard cranial and intraoral radiographs and three-dimensional reconstructions of computerized tomographic (CT) scans provided thorough and noninvasive methods of studying the craniofacial complex and extracranial skeleton. By this technique, major findings were: intact premaxilla, interpremaxillary, and premaxillary/maxillary sutures; intramaxillary cleft with ipsilateral choanal atresia; mildly asymmetric inferior turbinates; and normal nasal septum and vomer. CONCLUSIONS: Except for choanal atresia, cleft palate was not associated with other major craniofacial or extracranial anomalies in this case. Choanal atresia has been observed at times with cleft palate, but to our knowledge, the association has not been reported in nonhuman primates. Cleft palate, with or without cleft lip, has been recognized in a variety of nonhuman primates, including the lemur, marmoset, tamarin, squirrel monkey, and macaque. Some occurrences are spontaneous, while others are syndromic and/or arise from genetic or teratogenic influences. Each mode of presentation is poorly understood in nonhuman primates, but in this case, the absence of relevant environmental or parental history suggests that the occurrence was spontaneous. Anatomic studies of nonhuman primates are particularly valuable when they involve endangered species and will hopefully increase our understanding of the pathogenesis and etiology of congenital disorders, as well as other relationships between nonhuman primates and humans.

Appearance of ossification centers of the lower arm, wrist, lower leg, and ankle in immature orangutans and chimpanzees with an assessment of the relationship of ossification to dental development.

This study examines the appearance of the secondary ossification centers in the lower arms, wrists, lower legs, and ankles of a cross-sectional sample of 20 infant orangutans and chimpanzees (15 of known age). The number of tarsal and carpal centers is analyzed relative to the degree of M1 development and the weight of individual animals. Variation in the appearance of these ossification centers is discussed relative to these variables and others. In addition, a sequence of appearance is established for the carpal and tarsal ossification centers in the orangutan and data is presented on the status of these centers in a fetal and newborn gorilla. Study results indicate that 1) there is variation in the number of secondary epiphyses present in animals of similar ages; 2) tarsal ossification is completed prior to carpal ossification in the orangutan; 3) there are indications of a relationship between weight and the number of ossification centers present in animals of similar age; and 4) there appears to be no evidence of specific relationships between carpal and tarsal development and M1 development.

Development of the orangutan permanent dentition: assessing patterns and variation in tooth development.

This study examines dental formation and alveolar emergence in a large cross-sectional sample composed primarily of wild-reared orangutans (N = 89) in order to provide information on the development of the permanent dentition in this hominoid and to address questions of variation in individual tooth formation, between teeth and between individuals. All specimens have been radiographed in lateral aspect and stages of crown and root formation recorded for all teeth. The ranges of crown and root formation of I1(1), C1(1), P4(4), M2(2), and M3(3) have been calculated relative to the stage of M1(1) development within a specific tooth quadrant. Then, for each specimen, BMDP scatterplot and nonparametric statistics have been used to graph changes in stages of these teeth relative to M1(1) stages and to examine relationships between pairs of upper and lower dental counterparts and between teeth of each jaw. Results indicate 1) high correlations between upper and lower tooth pairs and between many of the permanent teeth within individuals, 2) a relatively large range of variability in individual tooth development (multistage ranges relative to M1(1)), 3) greater variation in root development at emergence than earlier reports, and 4) evidence of variability within the sequence emergence pattern of the orangutan.

A comparison of radiographic and anatomical evidence of tooth development in infant apes.

This study assesses dental development in a sample of 8 known-age infant orangutans and chimpanzees in order to examine discrepancies between radiographic analyses of tooth development and the actual developing teeth. All crania were radiographed and any developing teeth then extracted for comparison. The height of deciduous teeth was measured both on the radiographs and on the extracted teeth to assess the accuracy of radiographic tooth measurements. A comparison between the radiographic and actual measurements of the deciduous teeth reveals substantial discrepancies. For permanent teeth, the degree of radiographic underestimation of tooth development was found to vary depending on the tooth being studied, its stage of development (early stages are particularly problematic) and the radiographic techniques used. Examination of the dissected teeth also revealed earlier times of onset of calcification for I2(2), C1(1), P3-4(3-4) and M2 than reported in previous studies. For the canine and M2(2), upper and lower homologues appear to begin development at different times, but there is no apparent difference in onset times between other upper and lower homologues.

Sexual dimorphism in the cranium of infant and juvenile organutans.

The present study examines sexual dimorphism in the cranium of the immature orangutan. A series of 37 craniometric dimensions were measured on 56 immature crania. The total sample was divided into two subsamples: infants and juveniles. Univariate statistics and an analysis of variance were prepared for each subsample. Results indicate that the males and females in both subsamples are significantly different (p less than or equal to 0.05) for two measures of skull length. Eight additional dimensions from the infant category also appear to differ significantly (p less than or equal to 0.05) between the sexes.