中国水韭属两个四倍体新种

水韭属(Isoëtes)是起源最为古老的水生维管植物,全属物种均被列为国家一级重点保护植物。通过对全国水韭属植物的调查和研究发现,不同产地的四倍体植株在形态上存在显著差异。基于形态学、孢粉学和细胞学证据,将分布于中国湖南省长沙地区和怀化地区的四倍体居群分别命名为隆平水韭(Isoëtes longpingii)和湘妃水韭(I. xiangfei),并详细描述了其形态特征。隆平水韭形态上与中华水韭(I. sinensis)相似,不同之处在于其大孢子具小的瘤状或冠状纹饰,叶细长而柔弱,长达60 cm; 该种也与六倍体东方水韭(I. orientalis)相似,不同之处在于其染色体44条,大孢子具瘤状或冠状纹饰。湘妃水韭的大孢子纹饰虽与二倍体云贵水韭(I. yunguiensis)相似,但在小孢子纹饰、孢子囊形状和染色体数目方面却不同。隆平水韭仅少数植株生长于湖南省宁乡市一处池塘,完全沉水生长,而湘妃水韭则分布于怀化市通道县和会同县的湿地。由于这两个新种的分布区狭窄,野生居群数量和个体数较少,栖息地环境受到人为干扰,因此根据IUCN红色名录评估标准,将隆平水韭评为极危(CR)等级,湘妃水韭评为易危(VU)等级。所编制的中国已知水韭属物种的分种检索表,为本属物种的鉴定和保护工作提供了重要参考。     

Cross‐taxon congruence of multiple diversity facets of freshwater assemblages is determined by large‐scale processes across China

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Population cycles in voles and lemmings: state of the science and future directions

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The effects of infant births on the sociosexual behavior and hormonal patterns of a cooperatively breeding primate (Cebuella pygmaea)

This study examined changes in the behavioral and hormonal patterns of cooperatively breeding pairs in a primate species with the passing of time and with specific reproductive events. We (1) compared patterns of sexual, agonistic, and affiliative behavior of newly paired pygmy marmosets with the same behavioral patterns immediately after the birth of their first set of infants; (2) determined if postpartum behavioral differences existed between pairs whose infants lived and those whose infants died; and (3) examined whether behavioral patterns changed over the course of ovarian cycles in parous pygmy marmosets as had been documented in nulliparous pairs. The behavior of pairs was recorded during daily half-hour focal samples for 60 days after pairing, and 30 or 60 days after the birth of infants for pairs whose litters died or lived, respectively. Daily urine samples from females during the study were analyzed for luteinizing hormone and pregnanediol glucuronide concentrations to determine dates of ovulation. The results indicated that males consistently altered their sexual behavior and olfactory monitoring of mates during periovulatory periods in the females' cycles both postpairing and postpartum, while similar rates of social and sexual behavior were maintained between the conditions. Sexual behavior occurred throughout the females' ovarian cycles. Peaks in sexual behavior during the periovulatory period in nulliparous pairs disappeared after the birth of infants. Pairs whose infants died showed higher rates of sexual behavior than pairs with surviving infants. Social and sexual behavior may function to maintain the relationship both during and outside of ovulation, especially with the loss of infants. © 1996 Wiley-Liss, Inc.     

Information content of sexual swellings and fecal steroids in sooty mangabeys (Cercocebus torquatus atys)

The accuracy and precision of sexual swellings and fecal steroids as measures of ovarian function and the periovulatory period were compared in 4 sexually mature, individually housed, sooty mangabey females. Fecal samples were collected daily over a 10-week period during the normal breeding season. Serum was collected 3×/week, daily during peak swelling, and sex skin was rated 5×/week on a 0–5 relative scale. Both fecal estradiol (fE₂) and progesterone (fP₄) were significantly correlated with serum values in composite E₂-aligned profiles and within the cycles of individual females with average correlations of r_s = 0.6. Follicular phase means for fE₂ and luteal phase means for fP₄ were significantly correlated with the serum means across cycles, suggesting that fecal concentrations could be used to accurately evaluate cycle phases within and across females. In contrast, the timing of peak swelling relative to the periovulatory period varied considerably across the cycles of individual females. Although maximum tumescence appears to bracket the periovulatory period, individual differences in the duration of peak swelling and the timing of its onset and end tend to obscure the exact time of ovulation in relation to maximal tumescence. These data illustrate the utility of fecal steroid analysis as a tool for further evaluation of the signal value of sexual skin and its role in mating interactions. © 1996 Wiley-Liss, Inc.     

Spatially patterned guild structure in larval parasitoids of cyclically outbreaking winter moth populations

1. Wide temporal fluctuations in host abundance are a potential source of instability and stochasticity in the spatiotemporal population dynamics of associated parasitoid species. Within parasitoid guilds (i.e. parasitoids with similar modes of host utilisation), a conceivable outcome is guild organisation according to a lottery model, in which guild members attain local dominance by colonising previously emptied habitats during increasing host density, before other guild members. In the spatial dimension, an expected manifestation of such dynamics is variable guild structure even across homogeneous habitats. 2. We examined the extent of large‐scale spatial patterning of guild characteristics in larval parasitoid wasps associated with cyclically outbreaking populations of the geometrid moth Operophtera brumata in northern Fennoscandia. The study was performed at the onset of the crash‐phase of the geometrid's outbreak cycle, along a 70‐km transect in costal northern Norway, characterised by largely homogeneous environmental conditions, except for a small climatic gradient. 3. There was a distinct large‐scale spatial turnover in dominance among the major parasitoid groups (i.e. guild structure) in O. brumata along the transect, whereas the total prevalence rate of the guild and its diversity showed no consistent variation. Guild structure was unrelated to host density. 4. Although group‐specific responses to a slight spatial climatic gradient cannot be rejected as a causal mechanism, we conclude that our results are consistent with the expectation from large‐scale stochastic extinction‐recolonisation dynamics among functionally equivalent parasitoids relying on a host with strongly cyclic population fluctuations.     

Tapirus balkanicus nov. sp., nouveau tapir (Perissodactyla, Mammalia) du Turolien de Bulgarie

A new species of Tapiridae, Tapirus balkanicus, is etablished for new material of the Bulgarian Upper Miocene. The comparison with other Neogene tapirids leads us to consider the upper jaw as more characteristic than the lower one for taxonomic determination and study of phyletic relations. A new subgenus, Meyeriscus, is created for Tapirus pannonicus, the most evolved European tapirid.

Résumé

Une nouvelle espèce de tapir est décrite, Tapirus balkanicus du Miocène supérieur de Bulgarie. La comparaison avec les espèces européennes du Miocène moyen (Tapirus teilen) au Villafranchien (Tapirus arvernensis) amènent à privilégier la denture supérieure sur l'inférieure pour la détermination et les rapports phylétiques éventuels entre les espèces. Pour l'espèce la plus évoluée de tous les Tapiridés européens, Tapirus pannonicus est proposé un nom de sous-genre particulier, Meyeriscus nov.     

Fish, Flows and Flood Plains: Links between Freshwater Fishes and their Environment in the Murray-Darling River System, Australia

Knowledge of the biology of native fishes of the Murray-Darling Basin is based largely on studies conducted under hatchery conditions and on a limited number of recreationally important species. From observations that increases in water level in aquaculture ponds initiate spawning in some species, and from limited studies of wild fishes and studies in overseas floodplain river systems, a perception has emerged of the importance of flooding and the flood plain in the life cycles of Murray-Darling fishes in general. However, there is little confirmatory evidence of the use of temporary floodplain habitats by larvae, juveniles or adults. The significance of in-channel habitats, especially for rearing, has received little attention. Murray-Darling fish species can be placed into three life history modes, based mainly on spawning style and time and developmental intervals of larvae at first feeding. Fish in each group may be able to take advantage of floods if the timing is right and prey are plentiful, however, the larvae of some species are able to recruit under non-flood conditions within the main river channel. This forms the basis of the low flow recruitment hypothesis, which attempts to explain why some species spawn during the warmest months and lowest flows and how they are able to recruit under these conditions. This hypothesis is then placed in the context of the current state of knowledge of the relationships between flow and the biology of Murray-Darling fishes, specifically cues for spawning, movement and recruitment. The lack of widespread evidence for floodplain use by any life history interval of fish may be due to a paucity of study, however, there are some fundamental factors, such as the predictability of timing and duration of high flow events as well as the lack of coincidence of high flows and high temperatures in some regions of the Basin, which may be important in determining the use of floodplain habitats by fish.     

Chloroplast DNA-relationship in palaeoaustralLopidium concinnum (Hypopterygiaceae, Musci). An example of stenoevolution in mosses Studies in austral temperate rain forest bryophytes 2

Evolutionary relationship between disjunct populations of the palaeoaustral moss taxonLopidium concinnum (Hypopterygiaceae) from New Zealand and southern South America were studied using non-coding chloroplast DNA sequences. No or only slight changes could be observed within the sequences oftrnT_UGU —trnL_UAA 5exon intergenic spacer,trnL_UAA intron andtrnL_UAA 3exon —trnF_GAA intergenic spacer. This indicates nearly no genetic divergence between extant New Zealand and Chilean populations, i.e. no significant differing pathways of evolution within the 80–60 million years of disrupted areas with interrupted gene flow. Molecular data support the idea of an old Gondwanan relict species of stenoevolutionary character. Ecological data on short-range dispersal strengthen this assessment.