A new species of Encheloclarias from Sumatra

Encheloclarias velatus sp. nov. is described from central Sumatra. It diers from its congeners in having confluent anal- and caudal-fin bases, number of anal-fin rays, number of caudal vertebrae, length of anal-fin base, body depth at anus, head length, snout length, and interorbital distance.     

苏门答腊直角步甲族三新种记述(鞘翅目:步甲总科)

记述印度尼西亚苏门答腊岛产直角步甲族3新种。     

Orangutan Home Range Size and Its Determinants in a Sumatran Swamp Forest

Orangutans (Pongo pygmaeus) in a Sumatran swamp forest used home ranges far larger than any described so far for the species, in spite of living at the highest density on record. Although it was difficult to estimate home range sizes, minimum reliably estimated home range sizes for adult females are ca. 850 ha, whereas subadult and adult males used ranges of at least ca. 2500 ha, and perhaps much more. Range overlap was very high: up to 16 adult females, 9 adult males and at least 15 subadult males were seen within a single 4-ha square in the center of the study area. We found no evidence for the use of seasonally distincthome ranges—commuters—, and only some subadult males may have been transients—wanderers—without a stable home range. The large size of the home ranges is attributed to the coarse grain of the habitat mosaic, with orangutans converging on parts with a high density of favored fruit trees. Orangutans at this swamp forest included a variety of habitat types within their ranges.     

Between <Emphasis Type="Italic">Adat</Emphasis> and State: Institutional Arrangements on Sumatra’s Forest Frontier

In Indonesia, with the recent eruption of local struggles over resources and now with the new decentralization reforms, there is renewed interest in the role of customary adat institutional arrangements in village government, land tenure, and forest management. On the basis of research carried out in one locality in Sumatra over 1996–99, this article considers the nature of local institutional arrangements, how they have evolved under various conditions, their complex interaction with the parallel State order, their response to economic fluctuations, and how particular institutional patterns lead to certain environmental outcomes. This article finds that as farmers adjust to the economic and political dynamics and the changing scarcity and value of different resources in this site, the adat arrangements are constantly renegotiated. Adat customary orders are tied to local notions of identity and associated notions of appropriateness, and as such constitute patterns of social ordering associated with both implicit deeply held social norms and more explicit rules. Considering the institutional pluralism characteristic of this area, this article concludes that, while the State and adat regimes often compete to control the direction of social change, they also constantly make accommodations, and in some respects need to be considered as mutually adjusting, intertwined orders.     

Status of the enigmatic Oriental genus Rhithrogeniella Ulmer, 1939 (Ephemeroptera,Heptageniidae)

Based on historic collections and new material from Sumatra and Java, the species Rhithrogeniella ornata Ulmer, 1939, type species of the genus Rhithrogeniella, is reinvestigated. The nymph is described for the first time and is closely related to the continental Southeast Asian species Rhithrogeniella tonkinensis Soldán and Braasch, 1986. Rhithrogeniella belongs to the subfamily Ecdyonurinae, and is related to the genera Nixe Flowers, 1980 and/or Paracinygmula Bajkova, 1975 based on characters of the nymphal stage. Species described from Taiwan in the genus Nixe are transferred to the genus Rhithrogeniella: Rh. littoralis (Kang and Yang, 1994) comb. n., Rh. mitifica (Kang and Yang, 1994) comb. n. and Rh. obscura (Kang and Yang, 1994) comb. n.     

Mammals of Borneo – small size on a large island

Aim Island mammals have featured prominently in models of the evolution of body size. Most of these models examine size evolution across a wide range of islands in order to test which island characteristics influence evolutionary pathways. Here, we examine the mammalian fauna of a single island, Borneo, where previous work has detected that some mammal species have evolved a relatively small size. We test whether Borneo is characterized by smaller mammals than adjacent areas, and examine possible causes for the different trajectories of size evolution between different Bornean species. Location Sundaland: Borneo, Sumatra, Java and the Malay/Thai Peninsula. Methods We compared the mammalian body size frequency distributions in the four areas to examine whether the large mammal fauna of Borneo is more depauperate than elsewhere. We measured specimens belonging to 54 mammal species that are shared between Borneo and any of the other areas in order to determine whether there is an intraspecific tendency for Bornean mammals to evolve small body size. Using data on diet, body size and geographical ranges we examine factors that are thought to influence body size. Results Borneo has fewer large mammals than the other areas, but this is not statistically significant. Large Bornean mammals are significantly smaller than their conspecifics in the other regions, while there are no differences between the body sizes of mammals on Sumatra, Java and the Malay/Thai Peninsula. The finding that large mammals show the greatest size difference between Borneo and elsewhere contrasts with some models of size evolution on islands of different areas. Diet does not correlate with the degree of size reduction. Sunda region endemics show a weaker tendency to be small on Borneo than do widespread species. Main conclusions We suggest that soil quality may drive size evolution by affecting primary productivity. On Borneo, where soils are generally poor in nutrients, this may both limit biomass and cause mammals to be reduced in body size. We hypothesize that widespread species respond to low resource abundance by reducing in size, while endemic elements of the fauna have had longer to adjust to local conditions by altering their behaviour, physiology and/or ecology, and are thus similar in size across the region.     

Borneo Illipe,a fat product from differentShorea spp. (Dipterocarpaceae)

Fat extracted from kernels of Shorea spp. (Dipterocarpaceae) in the tropical rainforests of Borneo and Sumatra are traded under the name Borneo Illipe. The fat is used in chocolate formulations. The majority of kernels collected are fromShorea species in the sectionPachycarpae. Fat characteristics ofShorea species in this section show differences in fat quality in relation to its use as exotic sources in Cocoa Butter Equivalent (CBE) formulations. In order to comment on the future potential of the naturally occurring tree populations distribution maps of fiveShorea spp. involved in Borneo Illipe utilization are presented.     

A regional perspective on the effects of human disturbance on the termites of Sundaland

The remains of the rainforests of Sundaland are threatened by logging,burning and conversion to agriculture. In this study theeffects of different levels of disturbance and recovery on termites wereexamined. This was carried out on a regional scale and incorporated sixdifferent disturbance effects. Termites were found to be strongly effected bydisturbance, particularly by complete removal of the forest canopy. Recoveryfrom severe disturbance is discussed and we find that completely cleared andfarmed land, when left fallow near to a source area of primary forest for over50 years, can completely recover its termite assemblage andassociated ecosystem services. Over larger areas termites do not recover fromdisturbance events for millennia. The conservation implications of our findingsare discussed, with reference to both the conservation of species and ofecosystem services. We propose that most Sundan termite species can be conservedin a relatively small area. However, termite composition and ecosystem processesthroughout the region may be altered forever, if current widespread rainforestdestruction is not halted.     

Feeding ecology of Late Pleistocene Muntiacus muntjak in the Padang Highlands (Sumatra)

The Dubois Collectie comprises around 1000 isolated fossil teeth of Muntiacus muntjak from the Padang Highlands in Sumatra. The majority were retrieved from one of the three fossil cave sites Lida Ajer, Sibrambang or Jambu. Lida Ajer is the only cave, for which exact location, geology as well as the age of the fossiliferous deposits are known. Using the mesowear method, we searched for differences in the dietary signal of Muntiacus muntjak and thus in the paleoenvironments of the three caves. Muntiacus muntjak from either one of the caves does not differ significantly in the composition of its diet, showing a mixed feeder signal. The samples of Lida Ajer and Sibrambang illustrate an increase of the mixed feeding component, which could be the result of higher seasonality.     

A redescription ofDiaphanosoma modigliani Richard, 1894 (Crustacea : Daphniiformes : Sididae)and an evaluation of its occurence outside Lake Toba (Sumatra)

A pelagic species of Diaphanosoma, D. modigliani is redescribed on material from the type locality (Lake Toba, Sumatra, Indonesia). Other records of this species in tropical Asia (India, Philippine Islands, Malaysia, Sri Lanka, Thailand) are either unsubstantiated or erroneous.