Primate Research
Online ISSN : 1880-2117
Print ISSN : 0912-4047
ISSN-L : 0912-4047
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Volume 23, Issue 2
Displaying 1-8 of 8 articles from this issue
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Original Article
  • Morphological Relationship Between Upper and Lower Molars in Platyrrhini
    Is the Wear Facet 8 Indicative of Hypocone?
    Tomohiko HORI
    Article type: Original Article
    2007 Volume 23 Issue 2 Pages 61-70
    Published: December 20, 2007
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2354/psj.23.61
    JOURNAL FREE ACCESS
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    The upper molars carry a good amount of information for identifying the fossil Platyrrhines, whereas the lower molars do not. However, the upper molars are not found so much as the lower molars. It is supposed that the occlusal feature of an upper molar is inferred from the occlusal morphology of the respective lower molar. It is hypothesized that wear facet 8 is indicative of the hypocone, as it is formed in the distal part of entocristid of a lower molar by the occlusion with hypocone which is important trait classifying Callitrichine from other Platyrrhines. However, the development of lingual cingulum may give confounding effect on the development of facet 8. In this study, using specimens of Saimiri (hypocone present), Callithrix (hypocone absent) and Saguinus(hypocone partially present), which had different degree of occlusal wearing, I observed both of the upper and lower first molars for the presence both of the wear facet 8 and hypocone under binocular microscopes. As a result, the formation of lower facet 8 was found to be strictly indicative of the hypocone without being influenced by the lingual cingulum. Application of this relationship on such Platyrrhine fossils as Aotus dindensis, Mohanamico hershkovitzi, Patasola magdalena, Xenothrix mcgregori, Nuciruptor rubricae, whose upper molars were not found, and therefore, which have not been properly classified, gave phylogenetic implications.
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Short Report
Research Report
  • Status Report of Hybridization in an Introduced Population of Rhesus Macaques (Macaca mulatta) with Native Japanese Macaques (M. fuscata) in the Bousou Peninsula, Chiba, Japan
    Yoshi KAWAMOTO, Sakie KAWAMOTO, Shizuka KAWAI, Kei SHIRAI, Atsuhisa YO ...
    2007 Volume 23 Issue 2 Pages 81-89
    Published: December 20, 2007
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2354/psj.23.81
    JOURNAL FREE ACCESS
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    We examined a total of 20 blood samples for assessment of the degree of hybridization between introduced rhesus macaques and native Japanese macaques in the Bousou Peninsula. Each individual was characterized by different kinds of genetic markers (two protein loci, mtDNA and one Y chromosome DNA) in order to evaluate paternal and maternal origin and the degree of hybridization. The sample individuals contained one adult male Japanese macaque, and all others were rhesus or rhesus hybrid born in the study population. Of these 19 natal, at least 15 (78.9 per cent) were hybrids. The estimated frequencies of Japanese macaque genes were 0.342 and 0.857 for autosomal and Y chromosomal genes, respectively. This result revealed a high degree of hybridization in the introduced rhesus population. A test for random mating suggested that the two species were intermixing without reproductive defects. As the habitat of native Japanese macaque troops on the peninsula are very close, removal of the hybrid population is urgently required to prevent the transfer of their genes into the Japanese macaque population. It is also important to begin monitoring for further potential gene flow between rhesus and Japanese macaques in the peninsula.
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Review
  • Neurophysiological Approaches to Metamemory Using Primates
    Akio TANAKA, Shintaro FUNAHASHI
    2007 Volume 23 Issue 2 Pages 91-105
    Published: December 20, 2007
    Released on J-STAGE: March 13, 2009
    DOIhttps://doi.org/10.2354/psj.23.91
    JOURNAL FREE ACCESS
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    Metamemory refers to the knowledge about one's own memory capabilities and mnemonic strategies that support efficient learning and memory, and/or to the awareness and recognition about on-going mnemonic processes as well as what is stored in memory. Psychological studies established experimental methods to investigate the accuracy of human metamnemonic judgments and demonstrated that humans were capable of monitoring their own memory accurately. Recently, a number of neuropsychological as well as neuroimaging studies have indicated that the prefrontal cortex plays a crucial role in metamemory. Meanwhile there have been growing interests in exploring metacognitive abilities in animals. These lines of studies have developed new experimental paradigms suitable for systematically investigating the capability of animals' metamemory. In this article, we first briefly review previous studies on metamemory in humans and animals. Based on the findings from these studies, we then discuss strategies for examining neuronal substrates of metamemory in monkeys through neurophysiological approaches.
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Research Report
Book Review
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