摘要:

The earliest stages of development and differentiation of deciduous and permanent teeth were studied in prenatal and perinatal tarsiers. Both deciduous and successional teeth develop at loci for I1, I2, C, P2–4. Relationships among the dental lamina, enamel organs, and successional lamina were used to determine tooth homologies. During the second half of prenatal life, dP2 and dl2 undergo abnormal development. Their dentin becomes fragmented, and these teeth are shed or resorbed without eruption during the perinatal period. Our study provides evidence of an intermediate phase in evolutionary tooth loss. These findings do not corroborate recent hypotheses of primate phylogeny based mainly on tooth eruption pattern

ISSN:0015-5713    

DOI:10.1159/000156018

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

A new picrodontid primate, Draconodus apertus, is described from the North Horn Formation, Dragon Canyon, central Utah, USA. The fauna from Dragon Canyon is considered to be early middle Paleocene (early Torrejonian) in age by faunal and paleomagnetic correlation with the sequence in the San Juan Basin, New Mexico. Draconodus is the earliest known member of the family Picrodontidae, and possesses a flattened, squared-off first upper molar with separated postpara- and premetacristae (thus forming incomplete centrocrista) and other primitive characters. The morphology of the teeth suggests that the last three upper teeth of the family Picrodontidae are homologous with M1M2M3 of other primates as traditionally designated, rather than ‘P5’M1M2. If Draconodus is close to the stem of the picrodontids, then Picrodus and Zanycteris probably represent separate lineages within the fam

ISSN:0015-5713    

DOI:10.1159/000156019

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

During a short period, wild chimpanzees of group K in the Mahale Mountains employ a set of several techniques, including tool use, to feed on one species of termite (Pseudacanthotermes spiniger). They appear to use each technique appropriately according to phenological changes in the prey insect’s activities. The chimpanzees also ingest small pieces of soil from the tower of P. spiniger’s mound throughout the year. Geophagy presumably makes them visually and tactually aware of the phenological changes of the termite’s reproductive cycle. Analyses of fecal samples from the chimpanzees indicate interannual fluctuations in the amount of termites ingested. On the other hand, the chimpanzees of group B, ranging to the north of group K, utilize a fishing technique to obtain another type of termite (Macrotermes ?herus) on a large scale during the first half of the wet season. Fecal analysis data show that chimpanzees of group B consume far more termites than those of group K. The probability that the same or similar tool-using techniques as fishing may be employed in feeding on different types of insects by chimpanzees of different unit groups according to subtle local differences in the insect fauna of their home ranges is disc

ISSN:0015-5713    

DOI:10.1159/000156020

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

The winter range utilization pattern of a Japanese macaque troop in a snowy habitat was studied. The vegetation areas essential for subsistence were found to be relatively undisturbed mixed and deciduous forests. The concept of essential resource area (ERA) is defined. Our comparison among three troops in the same habitat in the past and present with different population densities indicated that the per capita ERA is quite important in determining the range area. This implies that the population and range area are resource-correlated.

ISSN:0015-5713    

DOI:10.1159/000156021

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

Proboscis monkeys, Nasalis larvatus, were observed from a boat in coastal mangrove swamps in Brunei. The size of foraging parties varied from 2 to 63 individuals and there was evidence that these parties were of ephemoral composition. Mean group size was 13.8 (mode 6-10). Overall, parties comprised males:females:juveniles in the ratio 1:2.6:1.8. It is suggested that variation in the size of foraging parties may be a consequence of the patchy distribution of food trees amongst a forest of inedible Nipa fructicans.

ISSN:0015-5713    

DOI:10.1159/000156022

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

Analysis of intervals between successive births, or of the interval between spontaneous or induced abortion and subsequent birth, indicate that unlike most primates for which information is available, lactation does not consistently influence the ability of the common marmoset to conceive during the early post-partum period.

ISSN:0015-5713    

DOI:10.1159/000156023

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

The natural estrous cycle of captive Senegal galagos was analyzed from daily records of 11 cycling females for 18 months, and induction of vaginal estrus and ovulation by gonadotropins and estrogen were examined in 9 females. No seasonal trend in cycling was indicated, as at least 5 of the 11 cycling females exhibited vaginal estrus during each month. Cycle lengths and duration of estrus were consistent for each female but varied significantly among females. Individuals’ average cycle lengths ranged from 29.2 ± 0.8 to 39.3 ± 3.4 days, and duration of estrus from 4.8 ± 0.2 to 6.7 ± 0.4 days. Vaginal estrus was induced by PMSG and PMSG-HCG combinations, and by estradiol. The gonadotropins also induced growth and ovulation of more than one fol

ISSN:0015-5713    

DOI:10.1159/000156024

出版商:S. Karger AG    

年代:1982

数据来源: Karger

摘要:

Rates of survival, infant growth and fertility of rhesus monkeys with two, one and no C allele(s) at the transferrin locus are compared. Infants with no C allele experience slower growth rates than animals with either one or two C allele(s). While heterozygous females exhibit the highest infant growth rates among females, their fertility is lower and incidence of abortions and stillbirths is higher than for females with two or no C alleles. It is hypothesized that opposing directions of selection at different life-cycle stages maintain a stable equilibrium at the transferrin locus.

ISSN:0015-5713    

DOI:10.1159/000156025

出版商:S. Karger AG    

年代:1982

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156026

出版商:S. Karger AG    

年代:1982

数据来源: Karger

ISSN:0015-5713    

DOI:10.1159/000156027

出版商:S. Karger AG    

年代:1982

数据来源: Karger