Asian Program

Japanese

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Former Fellows

Dissertation Abstracts

Indonesia

Name	Ibnu Maryanto
Position	Researcher Research Centre for Biology, Indonesian Institute of Sciences
Japanese Advisor	Seigo HIGASHI Professor,Hokkaido University

  I studied taxonomy of Indonesian rats and bats, by measuring 498 samples (305 rats, 20 fruit bats and 173 insectivorous bats) collected by myself or others and deposited in Zoological Museum Bogoriense, Australian Museum, Sydney, Western Australian Museum, Perth and Singapore Raffles Museum. Furthermore, on the basis of data primarily collected for taxonomy, I analyzed the zoogeography of the Indonesian small mammals and compared the factors affecting their distribution among rats, fruit bats and insectivorous bats. Main results were:
  1) Comparison of cranial and external characters of the ricefield rat Rattus argentiventer collected from Thailand, Malaysia, and Indonesia (Sumatra, Kalimantan, Java, Bali, Lesser Sunda, Sulawesi and Irian Jaya) indicated that the ricefield rat from Thailand to Irian Jaya fell into four groups: Jawa group (Thailand, Malaysia, Sumatra and Jawa), Bali-Sulawesi group (Bali, Sulawesi, Lombok, Sumbawa, Adonara, Sangeang, Rinca, Flores, Lembata, Alor, Timor and Tanimbar Islands), Sumba group and Kalimantan group. A specimen from Irian Jaya was placed in Jawa group. The taxon from Kalimantan is described as a new subspecies, R. a. kalimantanensis subsp.nov.
  2) Comparison of cranial and external characters of mice Mus musculus indicate the occurrence of two distinct forms in southern and eastern Indonesia. The two forms were distinct from Mus musculus domesticus in Western Australia. The more widespread form was attributed to M. m. castaneus which occurred on Bali, Lombok, Flores, Lembata, Alor, Kai, Banda, Neira, Timor and Roti islands. The other form, which was a new record of Mus musculus from Kisar and Tanimbar Islands, differed consistently from M. m. castaneus and was unidentified in this study.
  3) Seven specimens of Melomys, which were superficially most similar to members of M. leucogaster group (sensu, Tate 1951), were recently collected in Yamdena Island and Tanimbar Islands, eastern Indonesia. They are herein described as a new species Melomys cooperae sp.nov.
  4) In Lore Lindu National Park, Central Sulawesi, Indonesia, I caught a new rousset bat of Rousettus linduensis sp. nov. and compared with the other species of Rousettus in Indonesia, most notably with the common Sulawesian rouset bat (Rousettus celebensis). Nearly all skull, dentary and dental dimensions of this new species are smaller than R. celebensis. Moreover, unlike the common Sulawesian rouset bat, the breast fur is of a cream colour, the abdomen is negro to chocolate, and the sides are brown leather in the new speicis. Whereas the glans penis of Rousettus celebensis is flattened and triangular, the new species has glans penis of irregular shape.
  5) The analysis of a total of 173 adult specimens of Hipposideros previously allocated to H. larvatus indicated that the sharpest morphological boundary was between the Nusa Tenggara and Western Groups. The Nusa Tenggara specimens represent Hipposideros sumbae Oei, 1960. Most Nusa Tenggara islands examined had populations with a distinctive morphology; those from Sumbawa and Roti were subspecifically distinct from the nominate subspecies on Sumba. The subspecific status of populations on Sabu and Semau was indeterminate. Consequently, I describe Hipposideros sumbae rotiensis subsp.nov (Roti, Timor Islands), Hipposideros sumbae sumbawae subsp.nov (Sumbawa Island), Hipposideros sumbae subsp indet. A (Semau Island) and Hipposideros sumbae subsp indet. B (Sabu Island). The Western group comprised three distinct taxa: H. madurae sp. nov. with two subspecies Hipposideros madurae jenningsi subsp. nov and Hipposideros madurae madura subsp.nov; H. sorenseni sp. nov; and H. larvatus (Horsfield, 1823).
  6) As the consequence of zoogeography comparison of Indonesian rats, fruit bats and insectivorous bats, the endemicity, i.e. 100 x Ne / Nt where Ne and Nt are numbers of endemic and all species in the given island, respectively, was 12.5-75.7% in rats, 5.3-22.7% in fruit bats and 31.3-36.7% in insectivorous bats. Irian showed high endimicity in all of rats (73.4%), fruit bats (22.7%) and insectivorous bats (36.7%) The endemicity in Sulawesi was high in rats (75.7%) but relatively low in and fruit bats (10.7%) and insectivorous bats (7.8%).
  7) The numbers of rat, fruit bat, and insectivorous bat species were significantly correlated with island size when five major islands Irian, Borneo, Sumatra, Sulawesi and Jawa were included in the analysis. When these islands were excluded, the correlation between species richness and island size was significant in fruit and insectivorous bats but not in rats.
  8) Factors affecting the species richness of non-major islands were analyzed by multiple regression analysis where a dependent variable was the number of species and independent variables were island size, distance from the nearest major island, depth of sea isolating from the nearest major island and volcanic activity. Correlations were significant in all the rats, fruit bats and insectivorous bats. This analysis extracted significant factors as follows: sea depth in rats; island size, sea distance, sea depth and volcano in fruit bats; island size, sea depth and volcano in insectivorous bats.
  9) The zoogeographic boundaries of rats seem to lie between Sulawesi and Maluku and between Irian and its surrounding small islands. In addition to those boundaries, the present study found another boundary for rats between Sumatra and western Sumatra islands. For fruit bats, a zoogeographic boundary lies between northern Maluku and Irian but not between Northern Maluku and Sulawesi; an obvious boundary was not detected between Southern Maluku and Irian. For insectivorous bats, a zoogeographic boundary lies between Sulawesi and Maluku but not between Maluku and Irian.
  10) Wallace's line seems to be a zoogeographic boundary for all of three mammal groups with modification that Bali and Lombok belong to the cluster of Lesser Sunda in rats but to the cluster of Greater Sunda in bats. Weber's line also seems to be a zoogeographic boundary for all of the three mammal groups with modification that an effective boundary lies between Sulawesi and Maluku in rats and insectivorous bats but between northern Maluku and Irian in fruit bats. Lydekker's line seems to be a boundary for only rats, though Biak, Owi and Yapen belong to the cluster of Maluku. Finally, for all of the three small mammal groups, there is a distinctive border line between Sulawesi and Lesser Sunda.