Construction, Characterization, and Chromosomal Mapping of a Fosmid Library of the White-Cheeked Gibbon （Nomascus leucogenys）

Gibbons have experienced extensive karyotype rearrangements during evolution and represent an ideal model for studying the underlying molecular mechanism of evolutionary chromosomal rearrangements. It is anticipated that the cloning and sequence characterization of evolutionary chromosomal breakpoints will provide vital insights into the molecular force that has driven such a radical karyotype reshuffle in gibbons. We constructed and characterized a high-quality fosmid li- brary of the white-cheeked gibbon (Nomascus leucogenys) containing 192,000 non- redundant clones with an average insert size of 38 kb and 2.5-fold genome coverage. By end sequencing of 100 randomly selected fosmid clones, we generated 196 se- quence tags for the library. These end-sequenced fosmid clones were then mapped onto the chromosomes of the white-cheeked gibbon by fluorescence in situ hy- bridization, and no spurious chimeric clone was detected. BLAST search against the human genome showed a good correlation between the number of hit clones and the number of chromosomes, an indication of unbiased chromosomal distribu- tion of the fosmid library. The chromosomal distribution of the mapped clones is also consistent with the BLAST search result against human and white-cheeked gibbon genomes. The fosmid library and the mapped clones will serve as a valu- able resource for further studying gibbons' chromosomal rearrangements and the underlying molecular mechanism as well as for comparative genomic study in the lesser apes.     

The bronchial tree and lobular division of the lung of the white handed gibbon

The bronchial tree and lobular division of the lungs of four white handed gibbons (Hylobates agilis) were examined from the viewpoint of comparative anatomy, based upon the fundamental structure of the bronchial ramifications of the mammalian lung (Nakakuki, 1975, 1980). The right lung of the white handed gibbon consists of the upper, middle, lower, and accessory lobes, whereas the left lung consists of the middle and lower lobes. Each lobe is separated by the interlobular fissure, on both sides. The right and left lungs have the dorsal bronchiole system, lateral bronchiole system, and ventral bronchiole system. The medial bronchiole system is lacking on both sides. In the right lung, the upper lobe is formed by the first branch of the dorsal bronchiole system. The middle lobe is formed by the first brach of the lateral bronchiole system, and the accessory lobe by the first branch of the ventral bronchiole system. The remaining bronchioles constitute the right lower lobe. In the left lung, the upper lobe bronchiole, which is the first branch of the dorsal bronchiole system, is lacking. Therefore, the middle lobe bronchiole, i.e. the first branch of the lateral bronchiole system, is well developed. The accessory lobe bronchiole, the first branch of the ventral bronchiole system, is also lacking. The remaining bronchioles constitute the left lower lobe. These features were compared with those of other apes and man.     

Type locality of Hylobates concolor leucogenys

Kloss [1929] restricted the type locality of the northern white-cheeked gibbon, Hylobates concolor leucogenys, on the basis of two specimens that were collected at Muang Khi, Laos, not at Muang Pak-Lay, Laos, as conventionally assumed. The locality difference is zoogeographically important because Muang Khi is east of the Mekong River, within the known range of H. c. leucogenys, whereas Muang Pak-Lay is west of the river, outside the known range of the subspecies. The type-locality restriction is appropriately amended.     

Population dynamics of hoolock gibbons (Hylobates hoolock) in Assam,India

Data are presented on group size, composition, and reproduction of several hoolock gibbon groups studied in different areas of Assam, India, between 1986 and 1988. Presence of fewer young than reported in earlier studies signals a grim future for these gibbons unless strict conservation measures are undertaken.     

Sumatran Orangutans and a Yellow-Cheeked Crested Gibbon Know What Is Where

In their natural habitats orangutans and gibbons have to solve spatial problems to find enough food, which is distributed over large areas and available at different times of the year. Therefore both species should evolve spatial memory skills to remember spatial locations and their content. We conducted 2 studies in a 1900-m² naturalistic outdoor enclosure. In the 1st study, we hid kiwi pieces in 10 different locations and placed kiwi pieces in a visible location. Individuals of both species approached significantly more food locations in the test condition than in the control condition in which no food was hidden. In the 2nd study, we hid 2 types of food in 10 different locations so that individuals had to remember which food type was where. We hid bananas on trees (banana condition) and grapes under bamboo shrubs (grape condition). We also placed oranges in full view (control condition) to rule out the possibility that finding food may automatically trigger an indiscriminate search. Individuals approached the banana locations more often in the banana than in the other 2 conditions. Some orangutans, but not the gibbon, also approached the grape locations more often in the grape than in the other 2 conditions. Individuals often returned to locations in which they previously found food and rarely revisited locations in the same session. We detected little influence of the food quantity and no influence of the distance to each location on the subjects' foraging behavior.     

Taxonomic note: Bunopithecus: A genus-level taxon for the hoolock gibbon (Hylobates hoolock)

The recent discovery that the hoolock gibbon (Hylobates hoolock [Harlan, 1834]) has a karyotype distinct from all other hylobatids provides a new and strong motive for revising gibbon taxonomy and establishing hoolocks in a separate, higher taxon. Revising Groves's taxonomy of 1972, we propose that hoolock, along with the fossil species sericus, occupy a subgenus, Bunopithecus. With the newly added taxon, the genus Hylobates would thus contain four subgenera: Bunopithecus, Hylobates, Nomascus, and Symphalangus.