Dietary reconstruction of the Amphipithecidae (Primates, Anthropoidea) from the Paleogene of South Asia and paleoecological implications

The primate family, Amphipithecidae, lived during the early Cenozoic in South Asia. In this study, the diet of late middle Eocene amphipithecids from the Pondaung Formation (Central Myanmar) is characterized using three different approaches: body mass estimation, shearing quotient quantification and dental microwear analysis. Our results are compared with other Paleogene amphipithecids from Thailand and Pakistan, and to the other members of the primate community from the Pondaung Formation. Our results indicate a majority of frugivores within this primate community. Pondaungia and “Amphipithecus” included hard objects, such as seeds and nuts, in their diet. Folivory is secondary for these taxa. Myanmarpithecus probably had a mixed diet based on fruit and leaves. Contrasting results and a unique dental morphology distinguish Ganlea from other amphipithecids. These render interpretation difficult but nevertheless indicate a diet tending towards leaves and fruit. However, the anterior dentition of Ganlea suggests that this taxon engaged in seed predation, using its protruding canine as a tool to husk hard fruits and obtain the soft seeds inside. Bahinia and Paukkaungia, two other Pondaung primates, are small (<500 g) and therefore would have depended on insects as their source of protein. As such, they occupied a very different ecological niche from Pondaung amphipithecids. This primate community is then compared with the Eocene-Oligocene primate communities of the Fayum from North Africa. Similarities between the late middle Eocene Pondaung primate community and extant equatorial and tropical South American primate communities are noted.     

The BC200 RNA Gene and Its Neural Expression Are Conserved in Anthropoidea (Primates)

The gene encoding BC200 RNA arose from a monomeric Alu element. Subsequently, the RNA had been recruited or exapted into a function of the nervous system. Here we confirm the presence of the BC200 gene in several primate species among the Anthropoidea. The period following the divergence of New World monkeys and Old World monkeys from their common ancestor is characterized by a significantly higher substitution rate in the examined 5′ flanking region than in the BC200 RNA coding region itself. Furthermore, the conservation of CpG dimers in the RNA coding region (200 bp) is drastically increased compared to the 5′ flanking region (∼400 bp) over all 12 species examined. Finally, the brain-specific expression pattern of BC200 RNA and its presence as a ribonucleoprotein particle (RNP) are conserved in Old World and New World monkeys. Our studies indicate that the gene encoding BC200 RNA was created at least 35–55 million years ago and its presence, mode of expression, and association with protein(s) as an RNP are under selective pressure. Received: 1 December 1997 / Accepted: 3 June 1998     

Dental development in Megaladapis edwardsi (Primates, Lemuriformes): implications for understanding life history variation in subfossil lemurs

Teeth grow incrementally and preserve within them a record of that incremental growth in the form of microscopic growth lines. Studying dental development in extinct and extant primates, and its relationship to adult brain and body size as well as other life history and ecological parameters (e.g., diet, somatic growth rates, gestation length, age at weaning), holds the potential to yield unparalleled insights into the life history profiles of fossil primates. Here, we address the absolute pace of dental development in Megaladapis edwardsi, a giant extinct lemur of Madagascar. By examining the microstructure of the first and developing second molars in a juvenile individual, we establish a chronology of molar crown development for this specimen (M1 CFT = 1.04 years; M2 CFT = 1.42 years) and determine its age at death (1.39 years). Microstructural data on prenatal M1 crown formation time allow us to calculate a minimum gestation length of 0.54 years for this species. Postnatal crown and root formation data allow us to estimate its age at M1 emergence (approximately 0.9 years) and to establish a minimum age for M2 emergence (>1.39 years). Finally, using reconstructions or estimates (drawn elsewhere) of adult body mass, brain size, and diet in Megaladapis, as well as the eruption sequence of its permanent teeth, we explore the efficacy of these variables in predicting the absolute pace of dental development in this fossil species. We test competing explanations of variation in crown formation timing across the order Primates. Brain size is the best single predictor of crown formation time in primates, but other variables help to explain the variation.     

Epiphyseal union and dental eruption in Macaca mulatta

Age of dental eruption and epiphyseal fusion is estimated for the permanent dentition and long bone epiphyses of rhesus macaques (Macaca mulatta), with 299 skeletons of individuals with known age of death, from the Cayo Santiago skeletal collection. Epiphyses at a given joint tend to fuse at the same time. While males and females tend to have the same pattern of epiphyseal fusion, females' epiphyses fuse earlier than those of males, espeically at the elbow and knee joints. The order of epiphyseal fusion in rhesus macaques follows the general primate pattern. Times of dental eruption for males and females are generally the same, except for the relatively late eruption of the canine in the males. The order of eruption follows a common primate pattern (dm2?M1?I1?I2?M2?(P3,P4)?C?M3). Multiple regressions were calculated in order to allow determination of developmental state, or predictions of chronological age, from epiphyseal fusion and/or dental eruption scores in juvenile rhesus macaques. Standard deviations of residuals from these regressions indicate considerable variation in developmental state among aminals of the same chronological age. The lack of correlation between residuals from the separate skeletal and dental regressions, indicates that skeletal and dental development are largely independent.     

Dental function and diet in the Carpolestidae (Primates, Plesiadapiformes)

Microwear analysis has long been used to infer dental function in primates; however, this is the first study to combine microwear and morphometric analyses to infer the dental function of the highly derived dentition of an early Tertiary primate. The Carpolestidae, a family of plesiadapiform primates, are characterized in part by a bladelike lower dentition (P4 and trigonid of M1). This study reveals a dual function of this dental complex. During the preparatory cycle, the tall, vertical enamel surfaces and broad basal lobes on P4 and trigonid of M1 probably functioned to wedge foods apart. This cycle is designated slicing-crushing and is uncommon among mammals, having been documented only for two extinct taxa: the multituberculates and the carpolestids. In addition to this special function, P4 and trigonid of M1 were used extensively with the molars in Phase I shearing. Facet analysis has revealed two new Phase I facets located on P3,4, whose formation is a result of normal Phase I movements and the derived morphology of these teeth. Slicing-crushing, used with Phase I shearing, would probably be most useful in processing food items of combined textures, particularly a soft interior covered by either a brittle or ductile coat, which are characteristic of an omnivorous diet composed of invertebrates, nuts, and seeds.     

Uniquely derived upper molar morphology of Eocene Amphipithecidae (Primates: Anthropoidea): Homology and phylogeny

The extinct Southeast Asian primate family Amphipithecidae is regularly cited in discussions of anthropoid origins, but its phylogenetic position remains controversial. In part, the lack of consensus regarding amphipithecid relationships can be attributed to uncertainty regarding the homology of upper molar structures in this group. Here, we describe a virtually pristine upper molar of Pondaungia cotteri from the late middle Eocene Pondaung Formation of Myanmar, which is the first example of a relatively unworn and well-preserved amphipithecid upper molar ever recovered. The distolingual upper molar cusp in this new specimen of Pondaungia appears to be a lingually displaced and enlarged metaconule, rather than a hypocone or pseudohypocone as previous workers have thought. Reassessment of the upper molar morphology of other amphipithecids and putative amphipithecids reveals a very similar pattern in Siamopithecus, Myanmarpithecus and Ganlea, all of which are interpreted as having upper molars showing many of the same derived features apparent in Pondaungia. In contrast, the upper molar morphology of Bugtipithecus diverges radically from that of undoubted amphipithecids, and the latter taxon is excluded from Amphipithecidae on this basis. Phylogenetic analyses of several character–taxon matrices culled from the recent literature and updated to reflect the new information on amphipithecid upper molar morphology yield similar results. Consensus tree topologies derived from these analyses support amphipithecid monophyly and stable relationships within Amphipithecidae. Amphipithecids appear to be stem members of the anthropoid clade.     

Aspects of dental development in the orangutan prior to eruption of the permanent dentition

In spite of a resurgence of interest in the interpretation of the sequences of dental development and eruption in various Plio-Pleistocene hominoids as being either “modern human” or “ape-like,” the body of comparative material on the extant hominoids remains deficient in critical areas. In concert with recent attempts to rectify this situation, we present the results of our studies on dental morphogenesis in the orangutan. We have focused on the growth and eruption of the deciduous dentition as well as early stages of permanent tooth formation and have found that 1) many permanent teeth develop earlier than was thought, 2) differences exist between development in the upper and in the lower jaw, and 3) states of tooth formation can vary significantly among individuals of similar chronological age or tooth eruption status.     

Continuous dental eruption identifies Sts 5 as the developmentally oldest fossil hominin and informs the taxonomy of Australopithecus africanus

The relatively small Australopithecus africanus specimen Sts 5 has figured prominently in taxonomic debates, and the determination of this specimen as a young male or an elderly female has the potential to offer a great deal of resolution on this question. Sts 5 has been argued to be either a small, immature male or a mature female based on a variety of characters.     

Dental eruption sequence and eruption times in Erythrocebus patas

Erythrocebus patas has a short inter-birth interval, juveniles become independent from their mother early, females are young at first birth, and adult females have a high mortality rate. According to Schultz’s rule, the molars of fast-growing and shorter-lived primate species erupt early relative to the replacement teeth. Based on the life history of E. patas, we hypothesized that the molars would erupt before the replacement teeth and/or that the eruption time of its molars would be early. The purpose of the present study was to determine the dental eruption sequence and eruption times for E. patas and to test our hypothesis. The eruption sequence for the permanent teeth of E. patas is \frac\textM1  \textI1  \textI2  \textM2  \textP3  \textP4  [\textC  \textM3]\textM1  \textI1  \textI2  \textM2  \textP4  [\textP3  \textC]\textM3 \frac{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;{\text{M2}}\;{\text{P3}}\;{\text{P4}}\;[{\text{C}}\;{\text{M3}}]}}{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;{\text{M2}}\;{\text{P4}}\;[{\text{P3}}\;{\text{C}}]{\text{M3}}}} in males and \frac\textM1  \textI1  \textI2  [\textM2  \textP4  \textP3  \textC]\textM3\textM1  \textI1  \textI2  [\textM2  \textP4  \textP3  \textC]\textM3 \frac{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;[{\text{M2}}\;{\text{P4}}\;{\text{P3}}\;{\text{C}}]{\text{M3}}}}{{{\text{M1}}\;{\text{I1}}\;{\text{I2}}\;[{\text{M2}}\;{\text{P4}}\;{\text{P3}}\;{\text{C}}]{\text{M3}}}} in females. Because these sequences constitute the general pattern seen in cercopithecines, Schultz’s rule could not be applied to E. patas. The emergence time of upper and lower first molar (M1) is earlier in E. patas than in macaques, baboons, and mandrills and is similar to that in Chlorocebus aethiops. The emergence time of deciduous upper and lower fourth premolar (dp4) is similar to that in the above-mentioned cercopithecines but is later than that in Ch. aethiops. The emergence times of upper and lower second molar (M2) and upper and lower third molar (M3) in E. patas are earlier than those in the above-mentioned cercopithecines but later than those in Ch. aethiops. However, the intervals of the emergence time between each permanent molar in E. patas are similar to those of the above-mentioned cercopithecines. The early appearance of M2 and M3 in E. patas is related to the short interval of emergence time between dp4 and M1.     

Dental remains from the Grotte du Renne at Arcy-sur-Cure (Yonne)

Human remains associated with the earliest Upper Paleolithic industries are sparse. What is preserved is often fragmentary, making it difficult to accurately assign them to a particular species. For some time it has been generally accepted that Neandertals were responsible for the Chatelperronian and anatomically modern humans for the early Aurignacian industries. However, the recent re-dating of several of the more-complete modern human fossils associated with the early Aurignacian (e.g., Vogelherd) has led some to question the identity of the makers and the context of these early Upper Paleolithic industries. The Grotte du Renne at Arcy-sur-Cure, France has yielded many hominin remains, from Mousterian, Chatelperronian, Aurignacian, and Gravettian layers. Previously, a child's temporal bone from the Chatelperronian Layer Xb was recognized as belonging to a Neandertal; however, most of the teeth from Chatelperronian layers VIII-X remain unpublished. We describe the dental remains from the Chatelperronian layers, place them in a comparative (Mousterian Neandertal and Upper Paleolithic modern human) context, and evaluate their taxonomic status. The teeth (n = 29) represent a minimum of six individuals aged from birth to adult. The permanent dental sample (n = 15) from the Chatelperronian layers of Arcy-sur-Cure exhibits traits (e.g., lower molar mid-trigonid crest) that occur more frequently in Neandertals than in Upper Paleolithic modern humans. Furthermore, several teeth show trait combinations, including Cusp 6/mid-trigonid crest/anterior fovea in the lower second molar, that are rare or absent in Upper Paleolithic modern humans. The deciduous teeth (n = 14) significantly increase the sample of known deciduous hominin teeth and are more similar to Mousterian Neandertals from Europe and Asia than to Upper Paleolithic modern humans. Thus, the preponderance of dental evidence from the Grotte du Renne strongly supports that Neandertals were responsible for the Chatelperronian industry at Arcy-sur-Cure.     

Dental remains from Dmanisi (Republic of Georgia): morphological analysis and comparative study

The systematic excavation of the Dmanisi site (Republic of Georgia) has provided the earliest evidence of hominins outside Africa, dating back to ca. 1.8Ma. The analysis of the hominin remains has mainly focused on the morphology of the crania and mandibles. We present the first detailed morphological analysis and comparison of the Dmanisi teeth. The dental evidence from Dmanisi shows a unique combination of primitive and derived traits. In general, although the Dmanisi dental fossils show primitive morphology that resembles that seen in Australopithecus and H. habilis, they also display some derived characteristics, particularly in relation to dental reduction, resembling that seen in the dentition of H. erectus from the Far East.     

Developmental differences between singletons and twins in distributions of dental diameter asymmetries

Craniofacial development and behavioral development differs between human twins and singletons in several ways which are related to symmetry development and detectable in adults. In most of those ways, twin zygosity groups do not differ. Here we use distributions of dental diameters, as a model subsystem of craniofacial development, to show that twins, of both zygosities and both sexes, are substantially more symmetrical than singletons. The observed differences are consistent with previous related observations, none of which can readily be explained by any consequence of twin gestation. They seem instead to represent peculiarities of developmental biology familially associated with twinning.     

Measurements of tooth wear among Australian aborigines: II. Intrapopulational variation in patterns of dental attrition

The possible implications of variations in dental attrition patterns have necessitated a detailed assessment of the types, ranges, and causes of tooth wear. Hear we employ measurements of postcanine occlusal wear facets from a sample population of extant Australian aborigines. A principal components analysis was applied as a tool in determining common types of attritional patterns. It was concluded that the range of intrapopulational variation in dental wear patterns must be attributed to a multiplicity of sources in addition to such commonly cited causes as dietary variations, gender, age, and developmental eruption sequences.     

Sequences and timing of dental eruption in Bolivian captive-born squirrel monkeys (Saimiri sciureus)

Squirrel monkeys, colony-born from Bolivian parents, were studied to establish the sequences and timing of eruption for deciduous and permanent teeth. Infants were born with a naked gingiva, and in only one monkey was di₁ present at birth. The eruption of the lower deciduous teeth preceded their upper counterparts with the exception of di2, dc, and dpm2. No significant differences were found between the right and left quadrants of the mandible and maxilla. No significant sexual differences were found in the age of eruption. By the age of 14 weeks, all deciduous teeth had erupted. The sequence of eruption of the replacement teeth was different from that of milk teeth. The differences lie in the delayed eruption of canine teeth and in the inverted sequence, from the back to the front, of the premolar series. Significant sexual differences were found in total eruption (TE) for PM₃ and I² (P < 0.05) and highly significant differences (P < 0.01) in TE and initial eruption (IE) for C¹, females being more precocious than males. The age at which monkeys completed dental eruption was highly variable, 103–119 weeks for males and 89–112 weeks for females. Differences were found when our results were compared with those of Long and Cooper [1968] for Colombian squirrel monkeys.     

Enamel incremental periodicity in the pig-tailed macaque: A polychrome fluorescent labeling study of dental hard tissues

Bromage and Dean originally outlined a nondestructive method for the study of enamel formation and concluded that early hominids resembled the extant apes more closely than they did modern humans in their rates of growth and maturation. The method used assumed that an enamel circadian rhythmicity was referable to a longer near-weekly period represented by perikymata (periodic surface growth features). This assumption became a matter of debate and discussion. In this study, developing teeth in Macaca nemestrina were labeled with polychrome fluorescent dyes. Examination of the distribution of these dyes in two sectioned teeth provides experimental confirmation of enamel circadian periodicity.     

Preliminary investigation of dental microstructure in the Yuanmou hominoid (Lufengpithecus hudienensis), Yunnan Province,China

Fieldwork in the Yuanmou Basin of southern China has uncovered a large assemblage of late Miocene hominoid fossils assigned to Lufengpithecus hudienensis. Two mandibular first molars from this species were made available for histological analysis as part of a larger ongoing study on the ontogeny of dental development in Miocene to Recent hominoids. Results are compared with published and unpublished data on tooth growth in a wide range of extant and extinct hominoids. The Yuanmou molars are smaller than those of Lufengpithecus lufengensis and have markedly shorter crown formation times, overlapping slightly with Pan, but most similar to Proconsul and Dryopithecus. In other aspects of molar development (including enamel extension rates and enamel thickness), L. hudienensis shows similarities with all extant hominoids, in particular, Pongo. Ultimately, charting the ontogeny of molar crown formation may help shed light on the relationship of Lufengpithecus hudienensis to orangutans, and other Miocene to Recent hominoids.