Volume 72, Issue 4

A new species of white-toothed shrew, Crocidura phuquocensis , is described from Phu Quoc Island, southern Vietnam. The species is diagnosed on the basis of external and cranial morphology. Comparisons are provided with other species of Crocidura known to occur in Vietnam. The new species is the only soricid currently known to occur on Phu Quoc Island.

The monotypic Notiomys is the most poorly-known genus of Abrotrichini, a recently erected tribe of South American sigmodontine rodents. Based on a large sample, mostly recovered from owl pellets but including trapped individuals, we refine the known geographic distribution of this mouse (providing 20 new contemporary recording localities and four fossil occurrences), relate this to the principal Patagonian environmental units, add new data on the type locality of the species, and comment on its conservation status. In addition, we present a detailed external and craniodental description and provide data showing geographic variation of some skull features. Finally, we provide preliminary data on genetic variation (cytochrome b gene sequences) that demonstrate the existence of a low degree of observed differentiation (ca. 0.7%) between the populations analyzed.

Morphological diversity in the sciurid family was analysed by applying geometric morphometry (Fourier transform) to the mandible outline. The results obtained showed that phylogeny and ecology had a prominent role in shaping the mandible. Three distinct extreme forms are recognised illustrated by Marmota , dwarf tree squirrels and dwarf flying squirrels, respectively. Contrary to the mandible of the dwarf flying squirrel, the dwarf tree squirrel mandible does not have a developed coronoid process, while Marmota mandible is rather elongated. Tooth morphology, as well as chewing direction, studied by microwear analysis were only slightly variable and had no clear impact on the shape of the mandible. A study of the mandible of the Early Oligocene European squirrel Palaeosciurus goti did not contradict a preliminary interpretation (based on its limbs) that it had been a ground dweller, despite the fact that its mandible still exhibits a primitive outline.

The configurations of intermolar palatal ridges of 617 Norway rats ( Rattus norvegicus ) from 29 discrete rat populations from 28 US cities were examined and compared with palatal ridge patterns of other rodent species of the genus Rattus . This detailed study of the intermolar palatal ridges confirmed that the first intermolar ridge (I) has a distinguishing shape, which can be used as an aid in identifying Norway rats and revealed some minor morphological variations in shape, presence or absence of additional ridges, and occurrence of accessory denticles. Mammalian palatal ridges are generally flesh-colored; however, in these specimens an unusual feature was discovered, 13 of the 29 populations showed irregularly shaped, dark brown-pigmented parts of the intermolar ridges.

Spotting pigmentation was compared amongst three putative populations of Sousa chinensis : eastern Taiwan Strait (ETS; n=31), Pearl River Estuary (PRE; n=188) and Jiulong River Estuary (JRE; n=10). Spotting intensity on dorsal fins and bodies of each dolphin was scored from 1 (least spotted) to 4 (most spotted) by nine independent subjects and the means of their scores were analysed using analysis of variances (with post-hoc comparisons) and multiple t-tests. Dorsal fins of ETS dolphins were more spotted when compared to those of the PRE (p<0.0001) and JRE (p<0.0001), but those of PRE vs. JRE dolphins were not significantly different. Body spotting comparisons for all regions were not significantly different. The most noticeable character was the relative differences in spotting intensity between dorsal fins and bodies; dorsal fins were generally as, or more, spotted than bodies of ETS dolphins, while dorsal fins were generally less spotted than bodies of PRE and JRE dolphins. ETS dolphins also maintained spotting on their dorsal fins throughout all spotting phases of the body, whereas dorsal fins of PRE and JRE dolphins became unspotted well before their bodies. These results show that the ETS dolphins are distinct and apparently diagnosable from the PRE and JRE populations.

Small mammal assemblages were surveyed in five areas of the northern Junggar basin, Xinjiang, China, using standard trapping methods and index transects. In total, 23 species were recorded. The relationships between habitats and the distribution of the main species were described at local scale in Baihaba, Altai mountains. Three types of assemblages linked to (i) forest ( Myodes rufocanus , Microtus agrestis , Myodes rutilus , Apodemus peninsulae , Sorex isodon ), (ii) transitional areas and farmland (mixed pool of species including Apodemus uralensis ), and (iii) grassland ( Ellobius tancrei , Microtus obscurus , Cricetulus migratorius ) were identified. Additional species, such as Microtus oeconomus , could be found along small streams. At a broader scale, species composition was estimated in Kokehada, Narenhebuke and Fuhai areas and compared. Although ecological gradients from mountain grasslands to cold semi-desert partly explain differences in assemblage composition on a regional scale, similar habitats at the same altitude may, however, harbour different assemblages. For example, Spermophilus erythrogenys was the dominant species of the Kokehada grassland and Microtus obscurus and Ellobius tancrei were dominant in Baihaba grassland. In conclusion, the need for multi-scale standard descriptions of small mammal assemblage distribution in the northern Junggar basin of China is indicated.

Deforestation is a major environmental issue driving the loss of animal and plant species. Afforestation has recently been promoted to conserve and restore Chinese forest ecosystems. We investigated the distribution of small-mammal assemblages in an area where forest and associated deforestation habitats dominate, and in an agricultural area where afforestation is ongoing in the Loess Plateau of southern Ningxia Autonomous Region, P.R. China. Multiple trapping was used. Assemblages were defined based on the multinomial probability distribution and information theory. Species turnover between assemblages of deforested and afforested habitats was high, although no clear effect on species richness was observed. The two assemblages described along the deforestation gradient displayed higher diversity, whereas diversity was lower in assemblages identified in afforested habitats where Cricetulus longicaudatus , a known agricultural pest in various areas of China, clearly dominated. The threatened Sorex cylindricauda and Eozapus setchuanus were recorded along the deforestation gradient but not in plantations. Therefore, habitats present along a deforestation succession in this part of Ningxia sustain a high diversity of small mammals and include species of conservation concern. At the present stage of its process (maximum 15 years), afforestation in southern Ningxia favours the dominance of an agricultural pest.

Population characteristics of the polytocous Chinese water deer were studied and compared with those of other cervids and small ruminants. Numerous individuals living semi-freely on a large area were followed during 3 consecutive years. Animals were ear-tagged; matings, births and deaths were recorded. Although this captive population lived at high density, body masses were comparable to those of wild individuals, as were body growth, age at sexual maturity, periods of mating and birth, percentages of females giving birth, and death rates at any age. In contrast, litter size and proportion of young in the population were lower. On the whole, water deer differ from most other cervids by several characters corresponding to a high-population dynamic: short gestation, large litter size, reduced suckling phase, rapid body growth, early tooth replacement and sexual maturity, high mortality rate. However, in fact, water deer populations increase less in the wild than those of other species.

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