抄録
Using a principal components analysis on 17 logarithmically transformed cranial measurements, the sex differences of cranial size (SDCS) are calculated for five species of Sulawesi macaques, 0.559 in M. maurus, 0.545 in M. tonkeana, 0.514 in M. brunnescens, 0.438 in M. hecki and 0.331 in M. nigra, and are compared with those of non-Sulawesi macaques. The SDCS of Sulawesi macaques is highest in M. maurus, and decreases in accordance with the geographical distance from the species. The range of SDCS among Sulawesi macaques (0.559-0.331) is large and comparable to the range among non-Sulawesi macaques (0.598-0.329). The small SDCS of M. nigra is interpreted as a derived trait for Sulawesi macaques. To explain the small SDCS of M. nigra, it is inferred that in M. nigra as well as in M. hecki the level of male intrasexual competition is reflected in canine size rather than cranial size.
