珠三角河网裸藻的多样性特征

珠三角河网是珠江汇入南海的必经之地,2012年对该水域裸藻门及各属的多样性特征及影响因子进行系统阐析。调查期间共发现裸藻12属84种,其中裸藻属是最主要类群,其次为扁裸藻属和囊裸藻属。珠三角河网独特的地理位置和人类活动造成的水体富营养化是该水域裸藻物种多样性丰富的主要原因。季节特征显示,丰水期裸藻的种类丰富度和生物量均明显高于枯水期。除了洪水引发的裸藻物种的外源供给增大外,泄洪所带来的有机质的增加也是有利因素。此外,丰水期对应的高温也是有益条件。空间特征存在明显的季节差异,丰水期河网外侧站位的生物量和种类丰富度高于中部站位,主要原因是受径流影响较大;枯水季节除广州附近站位的值明显偏高外,其它站位间差异不大,营养盐的空间格局是主要决定因素。尽管裸藻主要依赖于沿江静水水体中的外源供给,分析表明,其在随水流下行的过程中存在增长过程。不同藻属相对组成的结果显示,扁裸藻属和囊裸藻属因属于生长缓慢的K-选择策略型,富集营养物质的能力不及裸藻属,仅在枯水期与裸藻属形成互补优势。裸藻门及主要属的生物量与种类丰富度呈线性正相关关系,偏重于多样性单峰模式的上升区。     

Life cycle and parasitic interaction of the lizard-parasitizing mite Ophionyssus galloticolus (Acari: Gamasida: Macronyssidae), with remarks about the evolutionary consequences of parasitism in mites

Wild-caught specimens of the lacertid lizard Gallotia galloti eisentrauti from the Canary Island of Tenerife were checked for ectoparasites. The parasitic gamasid mite Ophionyssus galloticolus Fain and Bannert (2000) was very abundant on these lizards. Additionally, parasitism by larvae of two species of Trombiculidae (Prostigmata: Parasitengona) was observed. O. galloticolus was reared in the laboratory on its natural host in order to investigate its life cycle, reproductive biology, and development. The life history of O. galloticolus is documented in detail and compared to literature data of other Ophionyssus species. O. galloticolus was found to be similar to other species of the same genus with respect to the duration of development, the precopulatory association of protonymphs, and the arrhenotokous development of eggs. However, it seems to be more tolerant towards low relative humidity and longer starvation periods than other Ophionyssus species. Evolutionary transformations of the life-history pattern of this genus and other parasitic mites in comparison to its predatory precursors involve a reduction or partial suppression of ontogenetic instars in order to decrease mortality during host-seeking phases, and a compensating increase in growth capacity of the remaining feeding instars facilitated by replacement of sclerites through elastic cuticle or by growth of new cuticle unrelated to a moult (neosomy).     

双花木属植物潜在分布区模拟与分析

气候变化直接影响着物种的分布范围。了解气候变化对濒危物种分布区的影响,是开展保护生物学研究的基础。双花木属(Disanthus Maxim.) 1种1变种,隶属金缕梅科(Hamamelidaceae),为东亚特有濒危物种和典型的中-日间断分布成分,在研究东亚植物区系地理演化方面具有重要的科学价值。本研究基于双花木属植物19个当前居群分布点的气候变量,运用MaxEnt模型预测双花木属植物在末次盛冰期(约22000年前)、当前(1950—2000年)和未来(2060—2080年)气候情景下的潜在分布区的结果显示,受试者工作特征曲线下的面积(AUC=0.9999±0.0001)接近于1,表明MaxEnt模型的预测准确度极高;气候变量贡献率和Jackknife检验评估的结果显示,制约双花木属植物分布的主导气候变量是最湿月降水量和最干月降水量。采用ArcGIS 10.0中的ArcToolbox空间分析工具定量分析比较双花木属的分布动态,基于生境稳定性(N_(stab))、当前与其他时期分布区面积比(N_a)和扩张/收缩程度(N_e)的分析结果揭示,在双花木属植物进化过程中,分布范围经历了收缩过程;未来的温室气体排放量升高程度不同,其适生区呈现不同程度(30%—65%)收缩,特别是RCP 8.5气候情景下,我国武夷山山脉的潜在分布区有可能会丧失。探讨双花木属植物对不同时期气候变化的响应,重建冰期以来该属植物地理分布的变迁历史,分析限制其潜在地理分布的主导气候变量,可为双花木属植物保育措施的制定和东亚地区植物区系物种形成演化的研究提供理论参考。     

Molecular characterization of haemococcidia genus Schellackia (Apicomplexa) reveals the polyphyletic origin of the family Lankesterellidae

The current taxonomy on the haemococcidia establishes that the two genera of protozoan parasites that integrate the family Lankesterellidae are Lankesterella and Schellackia. However, the phylogeny of these genera, as well as the other coccidia, remains unresolved. In this sense, the use of type and described species is essential for the resolution of systematic conflicts. In this study, we molecularly characterize the type species of the genus Schellackia, that is, S. bolivari from Europe and also a described species of the same genus from Asia. At the same time, we contribute with the molecular characterization of another species of the genus Lankesterella. All this put together supports the polyphyly of the family Lankesterellidae. Therefore, we propose the resurrection of the zoological family, Schellackiidae Grassé 1953 , to include species within the genus Schellackia.     

Extrafloral nectaries in the genus Macaranga (Euphorbiaceae) in Malaysia: comparative studies of their possible significance as predispositions for myrmecophytism

Some species of the paleotropical tree genus Macaranga (Euphorbiaceae) live in close association with ants. The genus comprises the full range of species from those not regularly inhabited by ants to obligate myrmecophytes. In Malaysia (Peninsular and Borneo) 23 of the 52 species are known to be ant-associated (44%). The simplest structural adaptation of plants to attract ants are extrafloral nectaries. We studied the distribution of extrafloral nectaries in the genus Macaranga to assess the significance of this character as a possible predisposition for the evolution of obligate myrmecophytism. All species have marginal glands on the leaves. However, only the glands of non- myrmecophytic species function as nectaries, whereas liquids secreted by these glands in myrmecophytic species did not contain sugar. Some non-myrmecophytic Macaranga and transitional Macaranga species in addition have extrafloral nectaries on the leaf blade near the petiole insertion. All obligatorily myrmecophytic Macaranga species, however, lack additional glands on the lamina. The non-myrmecophytic species are visited by a variety of different ant species, whereas myrmecophytic Macaranga are associated only with one specific ant-partner. Since these ants keep scale insects in the hollow stems, reduction of nectary production in ant-inhabited Macaranga seems to be biologically significant. We interpret this as a means of (a) saving the assimilates and (b) stabilization of maintenance of the association's specificity. Competition with other ant species for food rewards is avoided and thereby danger of weakening the protective function of the obligate ant- partner for the plant is reduced. A comparison with other euphorb species living in the same habitats as Macaranga showed that in genera in which extrafloral nectaries are widespread, no myrmecophytes have evolved. Possession of extrafloral nectaries does not appear to be essential for the development of symbiotic ant-plant interactions. Other predispositions such as nesting space might have played a more important role.     

New World biogeography and the evolution of polychromatism: evidence from the bee assassin genus Apiomerus (Heteroptera: Reduviidae: Harpactorinae)

The crassipes and pictipes species groups of Apiomerus Hahn together contain 12 species, many with high intraspecific chromatic variability, which represent the majority of Nearctic species in this New World assassin bug genus. Because of their geographical distribution and their varying degrees of polychromatism, these two species groups provide a unique opportunity to study the evolution of polychromatism and analyse relationships among areas of endemism in the Nearctic, as well as determine the boundary between the Nearctic and Neotropical regions. The results of a morphology based phylogenetic analysis allowed investigation of these questions while also determining relationships among the 12 species in the two species groups. The crassipes and pictipes species groups were each supported as monophyletic and as sister taxa. Apiomerus rufipennis (Fallou) was not included in the original concept of the crassipes species group, but is shown here to be a member of the group. Apiomerus barrocoloradoi Forero, Berniker & Szerlip, which had been hypothesized previously to belong to the pictipes species group, is excluded from this group. Intraspecific polychromatism for each species was identified as being present in one of three states: no polychromatism; limited polychromatism; or polychromatism as discrete colour morphs. Limited polychromatism was here found to be the ancestral state for Apiomerus, and species with discrete colour morphs are restricted to the crassipes and pictipes species groups. Polychromatism appears to be a greatly homoplastic character within the genus. A Brooks parsimony analysis recovered distinct Nearctic and Neotropical clades. The Nearctic clade is divided between areas in the central and eastern U.S.A. and areas in the Western U.S.A. and Mexico. The Nearctic–Neotropical boundary for the taxa included in the analysis is along the Isthmus of Tehuantepec in southern Mexico.     

Circadian Pattern of Wheel‐Running Activity of a South American Subterranean Rodent (Ctenomys cf knightii)

Circadian rhythms are regarded as essentially ubiquitous features of animal behavior and are thought to confer important adaptive advantages. However, although circadian systems of rodents have been among the most extensively studied, most comparative biology is restricted to a few related species. In this study, the circadian organization of locomotor activity was studied in the subterranean, solitary north Argentinean rodent, Ctenomys knightii. The genus, Ctenomys, commonly known as Tuco‐tucos, comprises more than 50 known species over a range that extends from 12°S latitude into Patagonia, and includes at least one social species. The genus, therefore, is ideal for comparative and ecological studies of circadian rhythms. Ctenomys knightii is the first of these to be studied for its circadian behavior. All animals were wild caught but adapted quickly to laboratory conditions, with clear and precise activity‐rest rhythms in a light‐dark (LD) cycle and strongly nocturnal wheel running behavior. In constant dark (DD), the rhythm expression persisted with free‐running periods always longer than 24 h. Upon reinstatement of the LD cycle, rhythms resynchronized rapidly with large phase advances in 7/8 animals. In constant light (LL), six animals had free‐running periods shorter than in DD, and 4/8 showed evidence of “splitting.” We conclude that under laboratory conditions, in wheel‐running cages, this species shows a clear nocturnal rhythmic organization controlled by an endogenous circadian oscillator that is entrained to 24 h LD cycles, predominantly by light‐induced advances, and shows the same interindividual variable responses to constant light as reported in other non‐subterranean species. These data are the first step toward understanding the chronobiology of the largest genus of subterranean rodents.     

Plants,fungi and bettongs: A fire-dependent co-evolutionary relationship

Digging activity by Bettongia gaimardi increased in small areas burnt by a low intensity fire at a site in northern Tasmania. A gap of several days occurred after the fire before digging began. Sporocarps of only one genus of mycorrhizal fungi (Mesophellia) were eaten by bettongs after the fire, in contrast to high numbers of species eaten in surrounding unburnt areas. It is hypothesized that the fire selectively stimulated the production of sporocarps by Mesophellia (a genus associated with eucalypts) rather than by simply making them more accessible or detectable. Stimulation of production of sporocarps by fire may ensure high infection rates and facilitate the uptake by eucalypts of nutrients released by the fire. These observations have important management implications.     

Morphological analysis and taxonomical status of four fish species of the genera <Emphasis Type="Italic">Opisthocentrus</Emphasis> and <Emphasis Type="Italic">Pholidapus</Emphasis> (Perciformes: Stichaeidae)

No common opinion on the systematics position of species of the fishes of the subfamily Opisthocentrinae, Stichaeidae family has been formed up to the present. Therefore, a morphological analysis of fishes belonging to taxa Opisthocentrus ocellatus, O. tenuis, O. zonope, and Pholidapus dybowskii was undertaken. The obtained data treated by various methods of statistics implied the species independence of these taxa, which sympatrically occurred in the coastal areas of the northwest of the Sea of Japan. All the four studied species were similar in some attributes and distinct by other. Minor differences in the structure of the seismosensory system of Ph. dybowskii and Opisthocentrus species gave no basis on which to distinguish the independent genus Pholidapus. It would be correct to consider this as a subgenus of the Opisthocentrus genus, which includes three other species.     

The subterranean genus Niphargus (Crustacea, Amphipoda) in the Middle East: A faunistic overview with descriptions of two new species

The Middle East is at the southeastern borderline of the range of the subterranean amphipod Niphargus. The review of new and published data identified two new species and set the guidelines for the future research in the area. The genus in this part of the world seems to be insufficiently studied. The taxonomic status of Niphargus valachicus, population identified as N. spoeckeri and some populations, identified as N. nadarini, need to be reviewed. According to present data, we expect the highest diversity in Western Turkey. The eventual new records of the genus in the Middle East can be expected from those areas where even the longest periods of drought in the recent geological history did not affect the water supply.     

How cold‐adapted flightless flies dispersed over the northern hemisphere: phylogeny and biogeography of the snow fly genus Chionea Dalman (Diptera: Limoniidae)

A phylogeny of the 37 known species and subspecies of the micropterous snow fly genus Chionea Dalman is presented using adult morphological characters. The genus contains two major clades: a strictly Palaearctic clade, and a combined Nearctic‐Palaearctic clade with representatives in the Nearctic and Western Palaearctic regions. As there is little congruence between the recovered phylogeny of Chionea and the currently used subgeneric division in Chionea s.s. and Sphaeconophilus Becker, we propose to abandon the use of subgeneric taxa in Chionea. A strictly morphological analysis appears to be insufficient to fully resolve the phylogeny of the genus at the species level, and future molecular work should provide additional evidence for the establishment of relationships among the members of Chionea. The large‐scale historical biogeography of Chionea was analysed using dispersal‐vicariance analysis. The initial distribution area of the genus probably extended in the Eastern Palaearctic, and the Nearctic and the origin of Chionea could be dated in the Late Cretaceous. The various dispersal and vicariance events that led to the major speciation events in the genus are set against major paleogeographic developments. The ancestor of the Western Palaearctic group in the second major clade originated from the Nearctic. The presence of the cold‐adapted Chionea in currently temperate to warm climatic zones in the southern parts of its distribution was analysed using ecological niche modelling. It appears that prolonged periods of climate cooling, as occurred during the Last Glacial Maximum, enabled Chionea to cover large parts of central and southern Europe and reach the southern distribution areas where the genus is present today. A similar biogeographic pattern was less evident in the Nearctic region.     

Enantiomeric conservation of the male‐produced sex pheromone facilitates monitoring of threatened European hermit beetles (Osmoderma spp.)

Hermit beetles of the genus Osmoderma (Coleoptera: Scarabaeidae: Cetoniinae) are known for their fruity odour, which is released in large amounts by males. Two species of the genus occur in Europe, the eastern Osmoderma barnabita (Motschulsky) and the western Osmoderma eremita (Scopoli). Previous studies on Swedish populations of O. eremita showed that the compound responsible for the characteristic scent, γ‐decalactone, functions as a sex pheromone for the attraction of conspecific females. Male O. eremita only release the (R)‐enantiomer of the lactone, and both sexes are anosmic to the opposite enantiomer. As the distribution areas of the two hermit beetle species partly overlap, it may be expected that they use different enantiomeric compositions of γ‐decalactone as pheromones to promote species discrimination. This paper reports on the identification of the sex pheromone of O. barnabita. Surprisingly, males from a Polish population produce only the (R)‐enantiomer of γ‐decalactone, and conspecific females show equal attraction to the (R)‐enantiomer and a racemic mixture of the compound, indicating that O. barnabita is anosmic to the (S)‐enantiomer, similarly to what was observed for O. eremita. A mtDNA sequence analysis of the cytochrome oxidase subunit I gene of Polish and Swedish beetles confirmed their taxonomical status as O. barnabita and O. eremita, respectively, with an average sequence divergence of 10.5% between beetles from the two studied areas. Although genetic data suggest that these species diverged several million years ago, they still rely on the same enantiomer of γ‐decalactone for mate finding. Thus, the male‐produced pheromone in Osmoderma spp. may be regarded as a territorial signal being exploited by females, rather than a cue for determining species identity. Our data show that the same compound can be used to facilitate monitoring of both beetle species, which are considered indicator species of the species‐rich fauna of saproxylic insects in Europe.     

Why are there so many species of mining bees (Hymenoptera,Andrenidae)? The possible roles of phenology and Wolbachia incompatibility in maintaining species boundaries in the Andrena proxima-complex

The factors leading to the extraordinary diversity of the bees of the genus Andrena Fabricius, the second most speciose genus among bees, remain largely unknown. To examine the pattern of diversification in this genus, we investigate species boundaries within the controversial Andrena proxima-complex using a dataset of ultra-conserved elements and various species delimitation analyses (admixture analyses, BPP, DAPC). Our results confirm the presence of three separate species in this species group (Andrena proxima (Kirby), A. ampla Warncke and A. alutacea Stöckhert) and suggest very low levels of interspecific gene flow. Andrena proxima and A. alutacea are regularly found in sympatry, suggesting an advanced stage of speciation. By contrast, A. ampla shows a parapatric distribution with both other species. Andrena alutacea harbours a unique strain of Wolbachia Hertig, absent in the other two species, which are infected by the two same strains of Wolbachia. In addition, the three species have distinct phenologies, with A. proxima flying earlier in the season and A. alutacea significantly later; the phenology of A. ampla is intermediate. Our results suggest that Wolbachia-induced incompatibilities and phenological differences maintain species boundaries in this group. The most advanced stage of speciation is observed in the two species showing putatively incompatible strains of Wolbachia and strongly distinct phenologies, A. alutacea and A. proxima. We propose that the smaller differences in phenological differentiation between A. ampla and both other species may explain the observed pattern of parapatric distribution. We discuss how these factors may underlie the high diversification rate observed in other groups of Andrena, a genus characterized by particularly variable and short flying periods.     

A pre‐Miocene Irano‐Turanian cradle: Origin and diversification of the species‐rich monocot genus Gagea (Liliaceae)

The Irano‐Turanian (IT) floristic region is considered an important center of origin for many taxa. However, there is a lack of studies dealing with typical IT genera that also occur in neighboring areas. The species‐rich monocot genus Gagea Salisb. shows a center of diversity in IT region and a distribution in adjacent regions, therefore representing a good study object to investigate spatial and temporal relationships among IT region and its neighboring areas (East Asia, Euro‐Siberia, Himalaya, and Mediterranean). We aimed at (a) testing the origin of the genus and of its major lineages in the IT region, (b) reconstructing divergence times, and (c) reconstructing colonization events. To address these problems, sequences of the ribosomal DNA internal transcribed spacer (ITS) region of 418 individuals and chloroplast intergenic spacers sequences (psbA‐trnH, trnL‐trnF) of 497 individuals, representing 116 species from all sections of the genus and nearly its entire distribution area were analyzed. Divergence times were estimated under a random molecular clock based on nrITS phylogeny, which was the most complete data set regarding the representation of species and distribution areas. Ancestral distribution ranges were estimated for the nrITS data set as well as for a combined data set, revealing that Gagea most likely originated in southwestern Asia. This genus first diversified there starting in the Early Miocene. In the Middle Miocene, Gagea migrated to the Mediterranean and to East Asia, while migration into Euro‐Siberia took place in the Late Miocene. During the Pleistocene, the Arctic was colonized and Gagea serotina, the most widespread species, reached North America. The Mediterranean basin was colonized multiple times from southwestern Asia or Euro‐Siberia. Most of the currently existing species originated during the last 3 Ma.     

苦苣苔科植物远缘杂交亲和性初探

该研究对苦苣苔科的蛛毛苣苔属[Paraboea(C.B.Clarke)Ridley]、马铃苣苔属(Oreocharis Bentham)、报春苣苔属(Primulina Hance)、吊石苣苔属(Lysionotus D.Don)、台闽苣苔属(Titanotrichum Solereder)、半蒴苣苔属(Hemiboea C.B.Clarke)、长蒴苣苔属(Didymocarpus Wallich)、光叶苣苔属(Glabrella Mich.MollerW.H.Chen)进行属间远缘杂交,对马铃苣苔属的马铃苣苔组、川滇马铃苣苔组、大叶石上莲组进行组间远缘杂交,统计不同杂交组合的结实情况及播种后的种子萌发情况,以明确不同属(组)间远缘杂交亲和性,为通过远缘杂交进行苦苣苔科种质资源的创新奠定基础。结果表明:(1)不同属作为父本,与同一母本进行杂交,以及同一属内不同种作为父本,与同一母本进行杂交,结实情况差异显著。(2)不同属作为母本,与同一父本进行杂交,以及同一属内不同种作为母本,与同一父本进行杂交,结实情况同样存在显著差异。(3)相同两个种正反交杂交成功率也并不一致。(4)马铃苣苔属与半蒴苣苔属,报春苣苔属与吊石苣苔属,吊石苣苔属与报春苣苔属和半蒴苣苔属,光叶苣苔属与报春苣苔属和吊石苣苔属之间部分种进行远缘杂交能够正常结实,且杂交种子能够正常萌发。(5)马铃苣苔属内组间杂交无明显生殖隔离的现象。     

Ecological evolution of ebracteates section of hydrophilic genus <Emphasis Type="Italic">Typha</Emphasis> L.

Reconstruction of the ecological evolution of the species of the ebracteatae section of genus Typha L. since the Eocene is proposed. The Typha and Engleria (Leonova) Tzvel. sections originated from different geological periods and in different regions of Eurasia. The explosion of the Typha section dated from the Poltava flora, while the Engleria section formed under the severe conditions of Arcto-Tertiary flora of East Siberia. The West Siberian Sea played a significant role in the ecological evolution of the sections. Taxonomic diversity as well as the sizes of areas of the investigated sections, with cold snaps established in Pliocene, resulted in exhaustion and insularization in the Pleistocene. The outlined trend toward convergence in the evolution of the sections of genus Typha was found in Holocene.     

Molecular phylogenetics of the burrowing crayfish genus Fallicambarus (Decapoda: Cambaridae)

Ainscough, B.J., Breinholt, J.W., Robison, H.W. & Crandall, K.A. (2013). Molecular phylogenetics of the burrowing crayfish genus Fallicambarus (Decapoda: Cambaridae). —Zoologica Scripta, 42, 306–316. The crayfish genus Fallicambarus contains 19 species of primary burrowing freshwater crayfish divided into two distinct subgenera. We test current hypotheses of the phylogenetic relationships among species within the genus as well as the monophyly of the genus. Our study samples all 19 species for five gene regions (both nuclear and mitochondrial) to estimate a robust phylogenetic hypothesis for the genus. We show that the genus is not a monophyletic group. The subgenus Creaserinus does fall out as a monophyletic group, but distinct from the subgenus Fallicambarus. The subgenus Fallicambarus appears to be monophyletic with the exception of the species Procambarus (Tenuicambarus) tenuis, which falls in the midst of this subgenus suggesting that it might be better classified as a Fallicambarus species. We also show that the species Fallicambarus fodiens is a species complex with distinct evolutionary lineages that are regionalized to different geographic areas.     

Taxonomic implications of genome size for all species of the genus Gasteria Duval (Aloaceae)

Nuclear DNA content (2C) is used as a new criterion to investigate all species of the genus Gasteria Duval including the three recently described species Gasteria polita van Jaarsv., G. pendulifolia van Jaarsv. and G. glauca van Jaarsv.. The 122 accessions investigated have the same chromosome number (2n=2x=14), with exception of three tetraploid plants found. The nuclear DNA content of the diploids, as measured by flow cytometry with Propidium Iodide, is demonstrated to range from 32.8–43.2 pg. This implies that the largest genome contains roughly 10¹⁰ more base pairs than the smallest. Based on DNA content the species could be divided in five groups: G. rawlinsonii Oberm. with 32.8 pg, 13 mostly inland species with 34.3–36.0 pg, five coastal species with 36.5–39.0 pg and Gasteria batesiana Rowley with 43.2 pg. The thirteen species with 34.3–36.0 pg could be divided further, in a group of eight species occupying mainly very restricted areas with 34.3–35.1 pg and a second group of five species with 35.2–36.0 pg mainly occupying large areas. These five groups did not coincide very well with the two sections and four series of Gasteria based on a cladistic analysis by van Jaarsveld et al. (1994). Based on its long leafy branches, location in the centre of Gasteria species distribution and its by far lowest DNA content, G. rawlinsonii might be the most primitive member of the genus. Nuclear DNA content as measured by flow cytometry is shown to be relevant to provide additional information on the relationships between Gasteria species.