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The low latitude Indian Ocean is warming faster than other tropical basins, and its interannual climate variability is projected to become more extreme under future emissions scenarios with substantial impacts on developing Indian Ocean rim countries. Therefore, it has become increasingly important to understand the drivers of regional precipitation in a changing climate. Here we present a new speleothem record from Anjohibe, a cave in northwest (NW) Madagascar well situated to record past changes in the Intertropical Convergence Zone (ITCZ). U‐Th ages date speleothem growth from 27 to 14 ka. δ18O, δ13C, and trace metal proxies reconstruct drier conditions during Heinrich Stadials 1 and 2, and wetter conditions during the Last Glacial Maximum and Bølling–Allerød. This is surprising considering hypotheses arguing for southward (northward) ITCZ shifts during North Atlantic cooling (warming) events, which would be expected to result in wetter (drier) conditions at Anjohibe in the Southern Hemisphere tropics. The reconstructed Indian Ocean zonal (west‐east) sea surface temperature (SST) gradient is in close agreement with hydroclimate proxies in NW Madagascar, with periods of increased precipitation correlating with relatively warmer conditions in the western Indian Ocean and cooler conditions in the eastern Indian Ocean. Such gradients could drive long‐term shifts in the strength of the Walker circulation with widespread effects on hydroclimate across East Africa. These results suggest that during abrupt millennial‐scale climate changes, it is not meridional ITCZ shifts, but the tropical Indian Ocean SST gradient and Walker circulation driving East African hydroclimate variability. Plain Language Summary: Long term monsoon dynamics in the southern Indian Ocean and Global South are not well constrained due to a lack of observational data. Paleoclimate records generated from archives like speleothems can help us fill gaps in our understanding. Here we use a speleothem record from Madagascar to test whether north‐south shifts in the tropical rain belt or west‐east changes in Indian Ocean temperatures are more important for precipitation in tropical East Africa. We find that ocean temperature gradients are the most important control on precipitation at our study site during previous instances of abrupt climate change linked to variability in the strength of North Atlantic ocean circulation. This work has important implications for how we think about the future of the tropical Indian Ocean sector in a changing climate. Key Points: Speleothem stable isotope and trace metal data agree on a dry Heinrich Stadial 1 and a wet Bølling–Allerød in northwest MadagascarHeinrich Stadial 1 and the Bølling‐Allerød show conditions contrary to responses expected from north‐south Intertropical Convergence Zone shiftsMillennial‐scale tropical East African hydroclimate variability is likely driven by zonal Indian Ocean sea surface temperature gradients [ABSTRACT FROM AUTHOR]

Objectives: The Holocene arrival of humans on Madagascar precipitated major changes to the island's biodiversity. The now‐extinct, endemic "subfossil" megafauna of Madagascar were likely hunted by early human inhabitants. Perhaps in part due to preferential hunting of larger prey, no surviving endemic species on Madagascar is >10 kg. Moreover, some subfossil bones of extant lemurs are considerably larger than those of the modern members of their species, but subfossil versus modern locale differences for the comparisons conducted to date lead to uncertainty about whether these size differences reflect in situ change or pre‐existing ecogeographic variation. Here, we revisited this question with samples from nearby locales. Materials and Methods: We used high‐resolution 3D scan data to conduct comparative morphological analyses of subfossil and modern skeletal remains of one of the larger extant lemurs, Verreaux's sifakas (Propithecus verreauxi) from subfossil and modern sites only ~10 km apart: Taolambiby (bones dated to 725–560—1075–955 cal. years before present) and Beza Mahafaly Special Reserve, respectively. Results: The mean aggregate score for all subfossil elements (n = 12; 0.089 ± 0.117) is significantly greater than that for the modern individuals (n = 31; 0.009 ± 0.045; t‐test; p = 0.039). We found that the average subfossil sifaka bone is ~9% larger than that of modern sifakas (permutation test p = 0.037). Discussion: We cannot yet conclude whether this size difference reflects evolutionary change or an archaeological aggregation/taphonomic process. However, if this is a case of phyletic dwarfism in response to human size‐selective harvesting pressures then the estimated rate of change is greater than those previously calculated for other archaeological cases of this phenomenon. [ABSTRACT FROM AUTHOR]

Madagascar is a complex 'biodiversity hotspot' with a rapidly dwindling biota. The Late Quaternary subfossil record includes many extinct species whose loss is attributed to natural climate change and human impacts. Investigation of the chronology of these events is challenging because few localities document pre‐Holocene communities not impacted by humans. Caves with extinct lemurs of large body size comprise some of Madagascar's richest subfossil sites, but provide only a limited window into the island's past. Open highland sites may have fewer primates, but may better document other megafauna, and allow the analysis of the role of the Central Highlands as refugia and as corridors for the dispersal of vertebrates before and after human arrival. Here we present a new subfossil site, Tsaramody (Sambaina basin, Central Madagascar), a high‐altitude wetland area that preserves a diverse late glacial and postglacial vertebrate community. Tsaramody bears testimony to fluctuations in the highland flora during the transition from glacial to postglacial conditions, and the composition of a highland vertebrate community before humans arrived. We compare its biota to those of other sites to begin to document the decline and disappearance of megafauna from some of Madagascar's open ecosystems – wetlands dominated by hippopotamuses and crocodylians. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The global paleomonsoon concept predicts an antiphase response of monsoon rainfall in the Northern and Southern Hemispheres at timescales where there is asymmetric solar forcing and/or asymmetric hemispheric temperature changes. However, as different monsoon systems have different sensitivities to local, regional, and global forcing, rainfall response may vary regionally, particularly during large global climatic changes such as the last deglaciation where warming occurred in both hemispheres. Despite its role as a key Southern Hemisphere counterpart to the Arabian and Indian summer monsoons, the behavior of the summer monsoon in the Southern Hemisphere of the Indian Ocean during the last deglaciation is unknown. Therefore, we present a new high‐resolution, precisely dated, and replicated speleothem stable isotope record from Tsimanampesotse National Park in southwest Madagascar that covers the last deglaciation. We show that speleothem growth phases respond largely to movements of the Southern Hemisphere summer Hadley circulation (summer extent of the tropical rainbelt/mean Intertropical Convergence Zone location), with some contribution from sea surface temperature changes at key times, such as during the Bølling‐Allerød. In contrast, speleothem δ18Ο responds primarily to sea surface temperature, in particular the location of the deep atmospheric convection isotherm, while summer Hadley circulation changes take a secondary role. Separating the varying influences of temperature and atmospheric circulation in controlling southwest Madagascan rainfall is critical to understanding rainfall variability in both the past and the future. Plain Language Summary: Understanding how monsoon rainfall might change under a changing climate is important to ensure the water supply for millions of people who depend on monsoon rainfall. Despite this, how Southern Hemisphere monsoon systems such as the Madagascan summer monsoon varied in the past are not well understood. We use stalagmites from Tsimanampesotse National Park in southwest Madagascar to create a new record of past changes in monsoon rainfall in the region. We use the timing of stalagmite growth and the stable isotopes of these stalagmites to reveal a series of wet and dry periods during the last deglaciation, a time of rapid climate change. Our new record shows that variability in monsoon rainfall is dependent on both temperature and atmospheric circulation changes. Both southward shifts in the tropical rainfall belt and warmer sea surface temperatures contributed to periods of higher rainfall in southwest Madagascar. Our rainfall sensitive site is able to detect changes in the monsoon that correspond to millennial‐ and centennial‐scale climatic events in the Northern Hemisphere, indicating links with the global tropical monsoon system. Key Points: Speleothem growth and stable isotopes in southwest Madagascar controlled by sea surface temperature and summer Hadley circulation movementSpeleothem δ18Ο follows a threshold response to sea surface temperatures above/below the deep atmospheric circulation isothermSecond order speleothem δ18Ο variability antiphase to northern hemisphere monsoon records, consistent with the global paleomonsoon concept [ABSTRACT FROM AUTHOR]

The reddish-gray mouse lemur ( Microcebus griseorufus) possesses striking phenotypic and behavioral variation. This project investigates differences in autopod proportions in neighboring populations of M. griseorufus from the Special Reserve at Bezà Mahafaly in southwest Madagascar. One population resides in an environment generally preferred by M. griseorufus-a spiny forest with large-trunked trees, vertically-oriented supports, and more open ground, while the other resides in a gallery forest with abundant small, often horizontal peripheral branches in high canopy. We demonstrate significant interpopulation differences in autopod morphophology despite no evidence of divergence in mitochondrial cytochrome b. We test two hypotheses regarding ultimate causation. The first, based on the Fine Branch Arborealism Hypothesis (FBAH), holds that autopod differences are related to different locomotor practices in the two environments, and the second, based on the Narrow Niche Hypothesis (NNH), holds that the observed differences reflect a relaxation (from ancestral to descendant conditions) of selective pressure for terrestrial locomotion and/or use of large, vertical supports combined with positive selection for locomoting in peripheral branch settings. Our data conform well to FBAH expectations and show some support for the NNH. Individuals from the gallery forest possess disproportionally long posterior digits that facilitate locomotion on small, flexible canopy supports while individuals from the spiny forest possess shorter posterior digits and a longer pollex/hallux that increase functional grasping diameter for large vertical supports and facilitate efficient ground locomotion. Focal individual data confirm differences in how often individuals descend to the ground and use vertical supports. We further show that predispersal juveniles, like adults, possess autopod morphologies suited to their natal forest. We explore two proximate mechanisms that could generate these cheiridial differences. The first posits an in vivo plastic response to different locomotor behaviors, the second posits differences that manifest in early development. [ABSTRACT FROM AUTHOR]

Researchers are divided about the relative importance of people versus climate in triggering the Late Holocene extinctions of the endemic large-bodied fauna on the island of Madagascar. Specifically, a dramatic and synchronous decline in arboreal pollen and increase in grass pollen ca 1000 yr ago has been alternatively interpreted as evidence for aridification, increased human activity, or both. As aridification and anthropogenic deforestation can have similar effects on vegetation, resolving which of these factors (if either) led to the demise of the megafauna on Madagascar has remained a challenge. We use stable nitrogen isotope (δ15N) values from radiocarbon-dated subfossil vertebrates to disentangle the relative importance of natural and human-induced changes. If increasing aridity were responsible for megafaunal decline, then we would expect an island-wide increase in δ15N values culminating in the highest values at the time of proposed maximum drought at ca 1000 yr ago. Alternatively, if climate were relatively stable and anthropogenic habitat alteration explains the palynological signal, then we would anticipate little or no change in habitat moisture, and no systematic, directional change in δ15N values over time. After accounting for the confounding influences of diet, geographic region, and coastal proximity, we find no change in δ15N values over the past 10 000 yr, and no support for a period of marked, geographically widespread aridification culminating 900-950 yr ago. Instead, increases in grasses at around that time may signal a transition in human land use to a more dedicated agro-pastoralist lifestyle, when megafaunal populations were already in decline. Land use changes ca 1000 yr ago would have simply accelerated the inevitable loss of Madagascar's megafauna. [ABSTRACT FROM AUTHOR]

Over 40 years ago, Clifford Jolly noted different ways in which Hadropithecus stenognathus converged in its craniodental anatomy with basal hominins and with geladas. The Malagasy subfossil lemur Hadropithecus departs from its sister taxon, Archaeolemur, in that it displays comparatively large molars, reduced incisors and canines, a shortened rostrum, and thickened mandibular corpus. Its molars, however, look nothing like those of basal hominins; rather, they much more closely resemble molars of grazers such as Theropithecus. A number of tools have been used to interpret these traits, including dental microwear and texture analysis, molar internal and external morphology, and finite element analysis of crania. These tools, however, have failed to provide support for a simple dietary interpretation; whereas there is some consistency in the inferences they support, dietary inferences (e.g., that it was graminivorous, or that it specialized on hard objects) have been downright contradictory. Cranial shape may correlate poorly with diet. But a fundamental question remains unresolved: why do the various cranial and dental convergences exemplified by Hadropithecus, basal hominins, and Theropithecus exist? In this paper we review prior hypotheses regarding the diet of Hadropithecus. We then use stable carbon and nitrogen isotope data to elucidate this species' diet, summarizing earlier stable isotope analyses and presenting new data for lemurs from the central highlands of Madagascar, where Hadropithecus exhibits an isotopic signature strikingly different from that seen in other parts of the island. We offer a dietary explanation for these differences. Hadropithecus likely specialized neither on grasses nor hard objects; its staples were probably the succulent leaves of CAM plants. Nevertheless, aspects of prior hypotheses regarding the ecological significance of its morphology can be supported. Am. J. Primatol. 78:1098-1112, 2016. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Small-bodied, nocturnal mouse lemurs ( Microcebus) are widespread across diverse forest habitats in Madagascar. They are strict seasonal breeders and can, depending on the habitat and species, undergo daily or prolonged torpor to minimize energy expenditure during periods of food and water scarcity. Duration of reproduction, number of litters per season and timing of births vary across individuals and species. The 'polyestry-seasonality' hypothesis proposes that the duration of reproduction and number of litters per year are positively correlated with rainfall but negatively correlated with longevity, whereas the 'hypervariability' hypothesis suggests that the duration of reproduction is negatively correlated with the degree of predictability of food resources. We test these hypotheses in two mouse lemur species inhabiting contrasting habitats, the brown mouse lemurs, Microcebus rufus, from Ranomafana (a less seasonal and more climatically predictable habitat) and the gray-brown mouse lemurs, M. griseorufus, from Beza Mahafaly (a more seasonal and less climatically predictable environment). We use capture/mark/recapture techniques and records of female reproductive status. We found evidence of polyestry at both study sites but faster population turnover and longer duration of the reproductive season at Beza Mahafaly. The 'polyestry-seasonality' hypothesis is not supported but the 'hypervariability' hypothesis could not be rejected. We conclude that reproductive output cannot be tied to climatic factors in a simple manner. Paradoxically, polyestry can be expressed in contrasting habitats: less seasonal forests where females can sustain multiple reproductive events, but also highly seasonal environments where females may not fatten sufficiently to sustain prolonged torpor but instead remain active throughout the year by relying on fallback resources. Am. J. Primatol. 77:936-947, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT We examine the ecology of reddish-gray mouse lemurs from three habitats at Beza Mahafaly Special Reserve using focal follows and stable carbon and nitrogen isotope data. Focal observations indicate dietary differences among habitats as well as sexes and seasons. Both sexes consume more arthropods during the rainy season but overall, females consume more sugar-rich exudates and fruit than males, and individuals from riparian forest consume fewer arthropods and more fruit than those in xeric or dry forest. We ask whether these observations are isotopically detectable. Isotope data support differences between seasons and sexes. Nitrogen isotope values are higher during the rainy season when lemurs consume more arthropods, and higher in males than females, particularly during the dry season. However, differences among populations inferred from focal observations are not fully supported. Lemurs from riparian forest have lower isotope values than those in xeric scrub, but isotope data suggest that lemurs from the dry forest eat the least animal matter and that focal observations overestimated dry forest arthropod consumption. Overall, our results suggest that observational and isotopic data are complementary. Isotope data can be obtained from a larger number of individuals and can quantify ingestion of animal matter, but they apparently cannot quantify the relative consumption of different sugar-rich foods. Combined focal and isotope data provide valuable insight into the dietary constraints of reddish-grey mouse lemurs, with implications for their vulnerability to future habitat change. Am J Phys Anthropol 155:77-90, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Understanding the paleoecology of extinct subfossil lemurs requires reconstruction of dietary preferences. Tooth morphology is strongly correlated with diet in living primates and is appropriate for inferring dietary ecology. Recently, dental topographic analysis has shown great promise in reconstructing diet from molar tooth form. Compared with traditionally used shearing metrics, dental topography is better suited for the extraordinary diversity of tooth form among subfossil lemurs and has been shown to be less sensitive to phylogenetic sources of shape variation. Specifically, we computed orientation patch counts rotated (OPCR) and Dirichlet normal energy (DNE) of molar teeth belonging to 14 species of subfossil lemurs and compared these values to those of an extant lemur sample. The two metrics succeeded in separating species in a manner that provides insights into both food processing and diet. We used them to examine the changes in lemur community ecology in Southern and Southwestern Madagascar that accompanied the extinction of giant lemurs. We show that the poverty of Madagascar's frugivore community is a long-standing phenomenon and that extinction of large-bodied lemurs in the South and Southwest resulted not merely in a loss of guild elements but also, most likely, in changes in the ecology of extant lemurs. Am J Phys Anthropol 148:215-227, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Aim We sought to quantify geographical variation in the stable isotope values of mouse lemurs ( Microcebus) and to determine whether this variation reflects trophic differences among populations or baseline isotopic differences among habitats. If the latter pattern is demonstrated, then Microcebus can become a proxy for tracking baseline habitat isotopic variability. Establishing such a baseline is crucial for identifying niche partitioning in modern and ancient communities. Location We studied five species of Microcebus from eight distinct habitats across Madagascar. Methods We compared isotopic variation in C3 plants and Microcebus fur within and among localities. We predicted that carbon and nitrogen isotope values of Microcebus should: (1) vary as a function of abiotic variables such as rainfall and temperature, and (2) covary with isotopic values in plants. We checked for trophic differences among Microcebus populations by comparing the average difference between mouse lemur and plant isotope values for each locality. We then used multiple regression models to explain spatial isotope variation in mouse lemurs, testing a suite of explanatory abiotic variables. Results We found substantial isotopic variation geographically. Ranges for mean isotope values were similar for both Microcebus and plants across localities (carbon 3.5-4.0‰; nitrogen 10.5-11.0‰). Mean mouse lemur and plant isotope values were lowest in cool, moist localities and highest in hot, dry localities. Rainfall explained 58% of the variation in Microcebus carbon isotope values, and mean plant nitrogen isotope values explained 99.7% of the variation in Microcebus nitrogen isotope values. Average differences between mouse lemur and plant isotope values (carbon 5.0‰; nitrogen 5.9‰) were similar across localities. Main conclusions Isotopic data suggest that trophic differences among Microcebus populations were small. Carbon isotope values in mouse lemurs were negatively correlated with rainfall. Nitrogen isotope values in Microcebus and plants covaried. Such findings suggest that nitrogen isotope values for Microcebus are a particularly good proxy for tracking baseline isotopic differences among habitats. Our results will facilitate future comparative research on modern mouse lemur communities, and ecological interpretations of extinct Holocene communities. [ABSTRACT FROM AUTHOR]

We summarize morphometric data collected over a period of 22 years from a natural population of rainforest sifakas ( Propithecus edwardsi) at Ranomafana National Park, Madagascar, and we use those data to document patterns of growth and development. Individually identified, known-age sifakas were successfully captured, measured, and released. We found that body segment lengths increased faster during growth than did body mass, with individuals attaining adult lengths earlier than adult mass. Females can begin reproducing before they are fully grown, but this may not be common. With the exception of hand length, we found no significant sex difference in any adult metric including body mass, chest, and limb circumferences, body segment lengths, and canine tooth height; however, body masses of individual females fluctuated more, independently of pregnancy, than did those of males. We found considerable interannual fluctuation in body mass with single individuals differing more within the same season in different years than from season to season in the same year. Such body mass fluctuation may be a consequence of eastern Madagascar's variable and unpredictable environment in which rainfall during any selected month varies from year to year. Am. J. Primatol. 73:155-172, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The Spiny Thicket Ecoregion (STE) of Southern and southwestern Madagascar was recently home to numerous giant lemurs and other 'megafauna,' including pygmy hippopotamuses, giant tortoises, elephant birds, and large euplerid carnivores. Following the arrival of humans more than 2,000 years ago, dramatic extinctions occurred. Only one-third of the lemur species which earlier occupied the STE survive today; other taxa suffered even greater losses. We use stable isotope biogeochemistry to reconstruct past diets and habitat preferences of the recently extinct lemurs of the STE. We show that the extinct lemurs occupied a wide range of niches, often distinct from those filled by coeval non-primates. Many of the now-extinct lemurs regularly exploited habitats that were drier than the gallery forests in which the remaining lemurs of this ecoregion are most often protected and studied. Most fed predominantly on C3 plants and some were likely the main dispersers of the large seeds of native C3 trees; others included CAM and/or C4 plants in their diets. These new data suggest that the recent extinctions have likely had significant ecological ramifications for the communities and ecosystems of Southern and southwestern Madagascar. Am. J. Primatol. 73:25-37, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Studies of primate life history variation are constrained by the fact that all large-bodied extant primates are haplorhines. However, large-bodied strepsirrhines recently existed. If we can extract life history information from their skeletons, these species can contribute to our understanding of primate life history variation. This is particularly important in light of new critiques of the classic "fast-slow continuum" as a descriptor of variation in life history profiles across mammals in general. We use established dental histological methods to estimate gestation length and age at weaning for five extinct lemur species. On the basis of these estimates, we reconstruct minimum interbirth intervals and maximum reproductive rates. We utilize principal components analysis to create a multivariate "life history space" that captures the relationships among reproductive parameters and brain and body size in extinct and extant lemurs. Our data show that, whereas large-bodied extinct lemurs can be described as "slow" in some fashion, they also varied greatly in their life history profiles. Those with relatively large brains also weaned their offspring late and had long interbirth intervals. These were not the largest of extinct lemurs. Thus, we distinguish size-related life history variation from variation that linked more strongly to ecological factors. Because all lemur species larger than 10 kg, regardless of life history profile, succumbed to extinction after humans arrived in Madagascar, we argue that large body size increased the probability of extinction independently of reproductive rate. We also provide some evidence that, among lemurs, brain size predicts reproductive rate better than body size. [ABSTRACT FROM AUTHOR]

Chemical deterioration of teeth is common among modern humans, and has been suggested for some extinct primates. Dental erosion caused by acidic foods may also obscure microwear signals of mechanical food properties. Ring-tailed lemurs at the Beza Mahafaly Special Reserve (BMSR), Madagascar, display frequent severe tooth wear and subsequent tooth loss. In contrast, sympatric Verreaux's sifaka display far less tooth wear and infrequent tooth loss, despite both species regularly consuming acidic tamarind fruit. We investigated the potential impact of dietary acidity on tooth wear, collecting data on salivary pH from both species, as well as salivary pH from ring-tailed lemurs at Tsimanampesotse National Park, Madagascar. We also collected salivary pH data from ring-tailed lemurs at the Indianapolis Zoo, none of which had eaten for at least 12 hr before data collection. Mean salivary pH for the BMSR ring-tailed lemurs (8.098, n=41, SD=0.550) was significantly more alkaline than Verreaux's sifaka (7.481, n=26, SD=0.458). The mean salivary pH of BMSR (8.098) and Tsimanampesotse (8.080, n=25, SD=0.746) ring-tailed lemurs did not differ significantly. Salivary pH for the Indianapolis Zoo sample (8.125, n=16, SD=0.289) did not differ significantly from either the BMSR or Tsimanampesotse ring-tailed lemurs, but was significantly more alkaline than the BMSR Verreaux's sifaka sample. Regardless of the time between feeding and collection of pH data (from several minutes to nearly 1 hr), salivary pH for each wild lemur was above the “critical” pH of 5.5, below which enamel demineralization occurs. Thus, the high pH of lemur saliva suggests a strong buffering capacity, indicating the impact of acidic foods on dental wear is short-lived, likely having a limited effect. However, tannins in tamarind fruit may increase friction between teeth, thereby increasing attrition and wear in lemurs. These data also suggest that salivary pH varies between lemur species, corresponding to broad dietary categories. Am. J. Primatol. 70:363–371, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The article profiles William White Howells, one of the twentieth century's intellectual giants of biological anthropology. Among his lifetime achievements are two honorary degrees from Beloit College and the University of the Witwatersrand as well as the Charles R. Darwin Lifetime Achievement Award. Howells' methodological contributions include applied statistics and the concepts of size and shape in the cranial vault. It also discusses his legacies as a professor in Harvard University.

Ontogenetic scaling has been hailed as an explanation of the differences in craniofacial morphology between adult males and females of a number of non human primate species. This inference has implications for the evolutionary processes underlying patterns of sexual variation, as several heterochronic processes (rate and time hypo- and hypermorphosis) predict ontogenetic scaling. Primary among species for which ontogenetic scaling of craniofacial dimensions has been claimed is Alouatta palliata, the mantled howling monkey. This study uses a variety of analytical tools to explore the efficacy of ontogenetic scaling as an explanatory paradigm for this classic example. Multivariate analysis captures shape far better than does bivariate analysis. However, multivariate analysis does not support the traditional inference of ontogenetic scaling. Explanations for contradictory results are considered. [ABSTRACT FROM AUTHOR]

Previous research on subfossil lemurs has revealed much about the positional behavior of these extinct strepsirrhines, but a thorough quantitative analysis of their vertebral form and function has not been performed. In this study, 156 lumbar vertebrae of Pachylemur, Archaeolemur, Megaladapis, Mesopropithecus, Babakotia, and Palaeopropithecus (11 species in all) were compared to those of 26 species of extant strepsirrhines and haplorhines. Lumbar shape was compared among species, using a principal components analysis (PCA) in conjunction with selected vertebral indices. The first principal component revealed strong separation between Palaeopropithecus at one extreme, and Archaeolemur/Pachylemur at the other, with Babakotia, Mesopropithecus, and Megaladapis in an intermediate position. Palaeopropithecus has markedly shorter spinous processes and wider laminae than do the other subfossil taxa, consistent with sloth-like, inverted suspensory postures. The moderately reduced lumbar spinous processes of Babakotia, Mesopropithecus, and Megaladapis are convergent with those of lorisids and Pongo, reflecting antipronogrady, but a less specialized adaptation than that of Palaeopropithecus. Archaeolemur and Pachylemur share relatively elongated spinous processes, in conjunction with other features (e.g., transverse process orientation and relatively short vertebral bodies) indicative of pronograde, quadrupedal locomotion characterized by reduced agility. All sub-fossil taxa exhibit adaptations emphasizing lumbar spinal stability (e.g., relatively short vertebral bodies, and transverse processes that are not oriented ventrally); we believe this probably reflects convergent mechanical demands connected to large body size, irrespective of specific locomotor mode. Reconstructions of positional behavior in subfossil lemurs based on lumbar vertebrae are largely consistent with those based on other aspects of the post-crania. [ABSTRACT FROM AUTHOR]

Paleontological expeditions to Madagascar over the past two decades have yielded large quantities of bones of extinct lemurs. These include abundant postcranial and cranial remains of new species belonging to a group of giant extinct lemurs that we have called sloth lemurs due to their remarkable postcranial convergence with arboreal sloths. New fossils have come from a variety of locations in Madagascar, including caves in the Northwest (Anjohibe) and the Ankarana Massif, located in the extreme north, as well as pits in the karstic plains near Toliara in southwestern Madagascar. The most spectacular of these is the extremely deep pit (>100 m) called Ankilitelo, the 'place of the three kily trees.' These new materials provide insights into the adaptive diversity and evolution of sloth lemurs. New carpal and pedal bones, as well as vertebrae and other portions of the axial skeletons, allow better reconstruction of the positional behavior of these animals. New analytical tools have begun to unlock the secrets of life-history adaptations of the Palaeopropithecidae, making explicit exactly what they had in common with their relatives, the Indriidae. Paleoecological research has elucidated the contexts in which they lived and the likely causes of their disappearance. [ABSTRACT FROM AUTHOR]

Explores the correlates of variation in dental development of primates. Discussion on the dental perocity and endowment in absolute ages; Variation in body or brain size and diet of primates; Exhibition of a rapid dental development in folivorous primates species.

Develops matrix representations of growth and shape change in human evolution using Stephen Jay Gould's clock model for heterochromic processes. Using a matrix approach to diagnose neoteny; Effect of neoteny on growth allometries and the timing of developmental events; Gould's neoteny hypothesis for human evolution; Paedomorphosis; Peramorphosis.

Reports on the subfossil specimen that expand the distribution of Indri indri into the drier northern tip of Madagascar. Paleoecological implications of the recovered specimens; Probability of forest corridors connecting the subfossil localities tot he current range at some time in the past; Effect of the climatic desiccation and/or human degradation of the environment.

Documents variation in rations of humeral head surface area to femoral head surface area among extant primates and other mammals. Subfossil Malagasy lemur forelimbs and hindlimbs pattern; Humerofemoral length index; Contributory factors to low humerofemoral head indices of primates; Relationship between joint surface area and force transmission.

Large body size has evolved repeatedly in the order Primates, not merely among anthropoids but also among prosimians. Whereas high degrees of sexual size dimorphism characterize many of the large-bodied anthropoids, this is not the case for extinct large-bodied lemurs. This paper uses finite mixture analysis and other techniques to ascertain just how much skull length dimorphism might be embedded in the generally unimodal distributions of skull lengths of giant extinct lemurs from single localities, and then compares these results with known skull length dimorphisms in extant lemurs and large-bodied catarrhines. We show that low levels of skull length sexual dimorphism (or none at all) characterize subfossil lemurs, and we explore several possible explanations for this phenomenon. Traditional explanations of sexual size dimorphism generally focus on body size or mating systems. These are not sufficient to explain the variation in sexual dimorphism that can be observed in the order Primates. © 1993 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The living Malagasy prosimians and their recently extinct subfossil relatives include about 20 genera and 8 families that can be considered one contemporaneous fauna. They exhibit morphological, behavioral, and ecological differences comparable to living anthropoid primates. This diversity is matched by the equally varied topography, climate, and vegetation of Madagascar. To investigate habitat-related size variation, skull lengths of wild-caught adults were used to compare sizes of closely-related conspecific and congeneric "sister taxa." More than 1,550 museum specimens were examined representing virtually all known forms of extant and subfossil Malagasy prosimians. A total of 98 pairwise, sister-taxa comparisons among 76 different taxa from six broadly defined ecogeographic regions revealed a consistent pattern of size variation: 1) the smallest Malagasy prosimians inhabit the semiarid forests, bush, and thickets of the South; 2) next largest are those from the dry deciduous forests of the West and the humid but seasonal forests of the Sambirano; 3) larger yet are those from humid tropical and secondary forests of the East; 4) the largest of all are the extinct forms of the central highlands that lived in what was probably a savanna-bush-woodland mosaic in the past but is now grasslands devoid of living prosimians. Taxa from the extreme North are more variable in size (small, intermediate, or large), which may reflect the mixture of local habitats in northern Madagascar. The ecogeographic size differences may be adaptive responses related to the carrying capacity of local environments such that smaller-sized species are favored where the resources they exploit are more limited. Field observations on behavioral thermoregulation, home range size, and population densities offer some support for this hypothesis. Ecologically induced size differences among local populations were probably one factor in speciation events leading to the modern diversity of the Malagas... [ABSTRACT FROM AUTHOR]