Semen cryopreservation in golden‐headed lion tamarin,Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden‐headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden‐headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm–egg‐binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short‐term measure for the conservation of golden‐headed lion tamarins.     

Effects of iodine deficiency on mental and psychomotor abilities

The allometric relationships between canine base area, first molar and summed molar crown area, and the glabella–opisthocranion distance, and the direct allometric relationships between canine and molar size have been established in five primate taxa. Separate sex and combined sex ‘intraspecific’, and ‘interspecific’ regression and ‘best fit’ allometry coefficients were computed. This analysis showed that for any increase in glabella–opisthocranion length, the rate of increase in canine size exceeds the rate of increase in molar area, and ‘best fit’ solutions indicate that canine base area is positively allometric when related directly to molar crown area. These results were compared with data available for the ‘gracile’ australopithecine, A. africanus, and two ‘robust’ australopithecine taxa, A. boisei and A. robustus. The differences in canine and molar size which occur between the ‘gracile’ taxon and the two ‘robust’ taxa do not correspond to any of the trends in the comparative allometric models. Data on glabella–opisthocranion length for the fossils, meagre though they are, show that while the proportional increase in molar crown area between the taxa corresponds to comparative allometry models, the reduced canine size in the ‘robust’ taxa is against comparative allometric trends. These results indicate that, at least in terms of canine/molar proportions, the differences between the ‘gracile’ and ‘robust’ australopithecines are not merely allometric and may indicate significant dietary or behavioural differences.     

Problems of body-weight estimation in fossil primates

Body-weight estimates of fossil primates are commonly used to infer many important aspects of primate paleobiology, including diet, ecology, and relative encephalization. It is important to examine carefully the methodologies and problems associated with such estimates and the degree to which one can have confidence in them. New regression equations for predicting body weight in fossil primates are given which provide body-weight estimates for most nonhominid primate species in the fossil record. The consequences of using different subgroups (evolutionary “grades”) of primate species to estimate fossil-primate body weights are explored and the implications of these results for interpreting the primate fossil record are discussed. All species (fossil and extant) were separated into the following “grades”: prosimian grade, monkey grade, ape grade, anthropoid grade, and all-primates grade. Regression equations relating lower molar size to body weight for each of these grades were then calculated. In addition, a female-anthropoid grade regression was also calculated for predicting body weight infernales of extinct, sexually dimorphic anthropoid species. These equations were then used to generate the fossil-primate body weights. In many instances, the predicted fossil-primate body weights differ substantially from previous estimates.     

The dentinoenamel junction in primates

Dental characteristics figure large in primate taxonomy because teeth fossilize commonly and reflect dietary adaptations. The mammalian dentinoenamel junction (DEJ) plays a crucial role throughout odontogenesis in determining the ultimate crown configuration, being the interface between the papilla and the dental cap. The final configuration of the dentin surface reflects the epithelium more closely than does the enamel surface of the crown. Enamel deposition occurs relatively late in calcification, often causing many changes from the pattern residing in the DEJ; the genetic determination of the two surfaces also differs. Comparative study of the DEJ (and its differences from the enamel crown) is a potential adjunct to dentition-based taxonomy and may help to resolve certain cusp homologies and morphogenetic order of appearance. Primate teeth were stripped of enamel after measurement, mapping, and anatomical observations on the original crown. The dentin surfaces thus revealed differ from the enamel surfaces in several respects and shed new light on such dental problem areas as the origin of the hypocone, the affinities of lorisoids and callitrichids, the monophyly of the anthropoid grade, and human affinities.     

Reproductive strategies,body size,and encephalization in primate evolution

In order to understand fully the generally high level of encephalization observed in living primates, we must determine why early primates exhibited moderately large relative brain sizes compared to their early Tertiary contemporaries. The relatively high degree of encephalization in early primates may be related at least in part to the fact that they were highly unusualamong mammals in combining a small body size with a strongly precocial reporductive strategy. Other small, precocial mammals also exhibit moderately high levels of encephalization; but primates appear to have been truly uniquein being the only such small-sized and highly precocial group to give rise to extensive radiations of larger descendants. This is a key element in understanding primate brain evolution, because the initial “head start” of the early primates was translated up to larger sizes in descendants. The possible relationships among encephalization, precociality, small size, and arboreality are discussed, particularly in light of recent debates concerning the validity of the superorder Archonta. This work emphasizes that we need to consider relative brain size as but one element in a complex synergistic network of morphological and life-history features.     

Hominid footprints at Laetoli: facts and interpretations

The history of discovery and interpretation of primate footprints at the site of Laetoli in northern Tanzania is reviewed. An analysis of the geological context of these tracks is provided. The hominid tracks in Tuff 7 at Site G in the Garusi River Valley demonstrate bipedality at a mid-Pliocene datum. Comparison of these tracks and the Hadar hominid foot fossils by Tuttle has led him to conclude that Australopithecus afarensis did not make the Tanzanian prints and that a more derived form of hominid is therefore indicated at Laetoli. An alternative interpretation has been offered by Stern and Susman who posit a conforming "transitional morphology" in both the Tanzanian prints and the Ethiopian bones. The present examines both hypotheses and shows that neither is likely to be entirely correct. To illustrate this point, a reconstruction of the foot skeleton of a female A. afarensis is undertaken, and the results are compared to the Laetoli tracks. We conclude that A. afarensis represents the best candidate for the maker of the Laetoli hominid trails.     

New details on the morphology of fossil onagraceous pollen grains

Fossil onagraceous pollen grains from two Upper Miocene localities in E. Austria were investigated by LM and EM. Exine structure and sculpture as well as viscin threads suggest affinities with the extant genusCircea.     

Coated nuts as an enrichment device to elicit tool use in tufted capuchins (Cebus apella)

The present paper describes a simple technique that hardens the shell of nuts and makes the use of a tool to crack them open more compelling. Walnuts were coated with a dough of sawdust and nontoxic white glue in different combinations; they were tested for hardness by using machines normally used to test different kinds of wood. Data on relative hardness for uncoated walnuts and walnuts coated with dough of two different combinations are presented. The coated walnuts were significantly harder to break than the uncoated ones, whereas no significant difference was found when comparing the hardness of two types of coated walnuts. Furthermore, observations on a captive group of tufted capuchins (Cebus apella) are described. The monkeys needed significantly more time to break open the coated walnuts. Early results show that coated walnuts may favor acquistion of tool use skills in a juvenile capuchin.     

云南建水早第三纪哺乳类的发现

本文记述了在云南省建水县岔科地区发现的哺乳动物化石。根据豫鼠(Yuomys),定地层时代为晚始新世。这套地层暂称岔科组,以示滇南地区第一个含早第三纪哺乳动物的地点和层位。     

A 7000-year pollen record from the Amazon lowlands,Ecuador

The longest continuous Amazonian palynological record (ca 7010 yrs B.P. to present) from Lake Ayauchⁱ, Ecuador, reveals species-by-species abundance changes during a period of climatic change. Pollen influx from a wet tropical rain forest was found to be high, 1×10⁴–10⁵ grains cm^-2 yr^-1, although mature forest taxa were poorly represented. Horizons of laminated sediments and weathered gyttja, dated to ca 4200–3150 B.P., evidence a period of reduced net water availability. During this period Ficus, Alchornea and Palmae pollen representation appears to decline, although there is no evidence of a major forest compositional change. The lake was reduced to a shallow, possibly seasonal, pool. Zea cultivation was recorded between ca 2850 B.P., (the earliest paleoecological record to date in the Amazon basin) and ca 800 B.P. It is suggested that Zea was cultivated on exposed lake sediment within the crater at times of low water levels. The abandonment of Zea cultivation may have been due to rising water levels or social unrest.