Offspring number in a livebearing fish (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>, Poeciliidae): reduced fecundity and reduced plasticity in a population of cave mollies

Life history traits within species often vary among different habitats. We measured female fecundity in mollies (Poecilia mexicana) from a H₂S-rich cave and from a neighbouring surface habitat, as well as in laboratory-reared individuals of both populations raised in either light or continuous darkness. Compared to conspecifics from surface habitats, cave-dwelling P. mexicana had reduced fecundity (adjusted for size) in the field. In the laboratory, the fecundity of surface mollies was higher in light than in darkness, whereas fecundity in the cave mollies was almost unaffected by the ambient light conditions. Our results suggest a heritable component to the reduction in fecundity in female cave mollies. Moreover, the reduced plasticity in fecundity of cave mollies in response to light conditions might be an example of genetic assimilation or channelling of a life history trait in a population invading a new environment.     

Fungi associated with aeroponic roots in caves and mines of New Brunswick

We provide the first analysis of the fungi associated with a very special habitat, the aeroponic roots found in caves and mines in New Brunswick, Canada. Fungal diversity was assessed by Illumina sequencing using three complementary primer sets targeting ribosomal RNA genes, and roots were identified using the non-coding trnH-psbA spacer. Early colonizing ectomycorrhizal fungi such as Agaricales, Helotiales, Pezizales, and Thelephorales were predominant. Saprotrophs, endophytes and plant pathogens were also present, but Glomeromycota (arbuscular mycorrhizal fungi) were not detected. Fungal root communities were generally most similar within sites. Fungal diversity was inversely correlated with winter dark zone temperatures and distance from the entrance. By using a combination of three primer sets, we detected more fungal taxa than with any one primer set. This study adds to the understanding of these subterranean ecosystems and suggests that future studies investigate factors limiting the presence of late-stage ectomycorrhizal fungi and Glomeromycota.     

猿人洞的溶洞演化和堆积旋回与北京猿人生活环境

猿人洞的溶洞演化过程按岩溶洞穴发生发展规律可划分为６个阶段．在洞穴发育的填充过程中,依据堆积物的成因类型,猿人洞中的中更新世洞穴堆积层可分为７个堆积旋回．每个堆积旋回可与年代相当的黄土堆积旋回和深海气候旋回—一对应．堆积旋回所显示的气候和洞穴环境变化均与北京猿人生活环境及其旧石器文化的发展有着密切的关系．     

Cave molly females (<Emphasis Type="Italic">Poecilia mexicana</Emphasis>) avoid parasitised males

Cave mollies (Poecilia mexicana) inhabit a dark Mexican cave, where visual communication is impossible. I observed the preference of cave molly females to associate with a non-infected male or a male infected with a pathogenic bacterium (Mycobacterium sp.) which causes the formation of large blisters around the eyes of infected fish. Females preferred to stay near the non-infected male only when the two stimulus males were separated from the female by transparent Plexiglas in light, but not when the males were separated by a wire-mesh in light (where vision was to some extent hindered, but the females perceived non-visual cues) or in darkness (where only non-visual cues were available). I conclude that the visually mediated preference for non-infected males has been maintained during the colonisation of the lightless habitat, but a preference for this trait on the basis of non-visual cues did not evolve. The cave habitat may be poor in pathogens, resulting in low selection pressure to evolve a non-visual preference for males without bacterial infection.Communicated by R.F. Oliveira     

贵州山岚桥洞内动物重金属富集的初步研究

2009年6月对贵州安顺市山岚桥洞内软体动物和节肢动物进行了采集。共获标本637号,初步鉴定隶属于2门4纲7目12科25种,合并为螺类、马陆、盲蛛、斑灶马、山蛩虫5个类群。利用原子吸收光谱仪和原子荧光仪测定洞内水、土壤及洞穴中5个类群动物体内的Pb、Cd、Hg、As、Cu、Zn、Cr、Ni8种重金属含量,计算水、土壤中重金属在动物体内的富集系数。结果表明,水、土壤及动物体内的Zn含量最高,水样为112.90μg/L,土样为224.60mg/kg,5个动物类群体内,螺类146.80mg/kg,马陆252.20mg/kg,盲蛛556.80mg/kg,斑灶马233.30mg/kg,山蛩虫722.50mg/kg;5个类群动物对洞穴土壤中Cd、Cu和Zn有明显的富集作用,富集系数均大于1;对洞穴水中As、Cu、Zn、Ni等有明显富集作用,富集系数大于1000。同种动物类群对不同重金属的富集系数不同,不同类群对同种重金属元素的富集系数也有差别。洞穴动物对重金属的富集作用,除了与元素之间相互关联外,还与环境有密切关系。     

贵州毕节发现古人类化石与哺乳动物群

2008年12月在贵州毕节团结乡首次发现麻窝口洞化石点,经2009年、2012年和2013年3次发掘,在麻窝口洞上部砂质黏土地层中共发现了四千余件哺乳动物牙齿化石。2013年7月发现的3枚古人类牙齿,分别为左上犬齿、左上第一臼齿和右上第二臼齿。人类牙齿尺寸偏小,臼齿咬合面沟纹简单,没有复杂的咬合面皱纹和附尖齿带结构,牙根短而不显粗壮,上述特点有别于我国已经发现的直立人和早期智人,可归入解剖学上的现代人。与人类相伴的哺乳动物化石,经初步鉴定共计8目20科43属53种,动物群组合反映出亚热带森林生态环境。根据动物群的时代特点,地貌地层及堆积物的光释光年代测定,指示毕节麻窝口洞古人类的时代可能为中更新世晚期,或者晚更新世早期,毕节古人类牙齿的发现为东亚地区现代人的起源及演化增添了新的证据。     

Life on the edge: hydrogen sulfide and the fish communities of a Mexican cave and surrounding waters

Most eucaryotic organisms classified as living in an extreme habitat are invertebrates. Here we report of a fish living in a Mexican cave (Cueva del Azufre) that is rich in highly toxic H₂S. We compared the water chemistry and fish communities of the cave and several nearby surface streams. Our study revealed high concentrations of H₂S in the cave and its outflow (El Azufre). The concentrations of H₂S reach more than 300 μM inside the cave, which are acutely toxic for most fishes. In both sulfidic habitats, the diversity of fishes was heavily reduced, and Poecilia mexicana was the dominant species indicating that the presence of H₂S has an all-or-none effect, permitting only few species to survive in sulfidic habitats. Compared to habitats without H₂S, P. mexicana from the cave and the outflow have a significantly lower body condition. Although there are microhabitats with varying concentrations of H₂S within the cave, we could not find a higher fish density in areas with lower concentrations of H₂S. We discuss that P. mexicana is one of the few extremophile vertebrates. Our study supports the idea that extreme habitats lead to an impoverished species diversity.     

Exceptional record of submarine cave communities from the Pleistocene of Sicily (Italy)

An Early Pleistocene benthic community, discovered inside the Rumena Cave in NW Sicily, Italy, was studied. Analysis of the community led to the recognition of several encrusting species – notably scleractinians, bryozoans, serpuloideans, cirripeds, foraminifera and brachiopods – and borings mostly referable to the ichnogenus Gastrochaenolites. All fossils detected are typical of the present‐day hard‐surface submarine cave biota, at both high taxonomic rank and species level. The biogenic crust, restricted to a few sectors of the cave but locally up to few centimetres thick, largely consist of scleractinians, mainly represented by dendrophylliids. Bryozoans and serpuloideans are also present with Hippaliosina depressa and Spiraserpula massiliensis, locally forming multi‐layered sheets and dense specimen aggregates, respectively. Basing mostly on the composition of the encrusting community and on morphological/morphometric features of some species, it has been hypothesized that at least part of the cave was blind when the crust formed, possibly at relatively shallow depth in a sheltered setting or, more probably, at higher depths, below the fair weather swell zone. Encrustations and borings on the rocky cave ceiling and on occasional speleothems broken surfaces document subsequent phases of cave submersion/colonization separated by emersion/erosion phases. The importance of the Early Pleistocene fossils of the Rumena Cave for the knowledge of submarine cave communities through time and for the understanding of sea‐level variations and the uplift of the area has been remarked.     

麦积山石窟赋存环境中空气细菌的时空分布特征

【目的】空气微生物沉降及污染与文化遗产的微生物退化密切相关,本文对世界文化遗产地麦积山石窟赋存环境空气中细菌浓度和群落结构的季节性变化特征进行了系统研究,为石窟环境监测预警和文物预防性保护提供依据。【方法】利用生物气溶胶采样器,在2016年春、夏、秋和冬季分别采集空气样品;基于传统培养方法获得空气中细菌浓度及纯培养菌株;通过提取基因组DNA、扩增细菌16S rRNA、测序和系统发生树等分子技术研究细菌群落时空动态变化规律;结合环境监测数据,分析影响遗产地空气细菌变化的主要因素。【结果】监测期内,空气细菌浓度在(281.20–1409.20)CFU/m3之间,最高浓度出现在MJ4处的夏季,最低浓度出现在MJO处的春季;具有明显季节性变化特征,在空间层位分布上有所差异,但不显著(P0.05)。培养的细菌菌株经鉴定属于4个门11个属;芽孢杆菌属(Bacillus)、Paenarthrobacter、节杆菌属(Arthrobacter)、薄层菌属(Hymenobacter)和考克氏菌属(Kocuria)等为优势属。【结论】麦积山石窟空气细菌群落结构具有明显的季节性和空间分布动态变化特征;在石窟不同层位,空气中细菌群落分布与相对湿度、温度与降雨量相关;部分细菌种属如芽孢杆菌属、微球菌属(Micrococcus),为壁画及彩塑生物腐蚀的潜在病害菌;麦积山石窟及周边环境空气细菌的监测可为石窟保护和旅游开放管理提供重要参考。     

First record of Macaca mulatta (Cercopithecidae: Papionini) from the Taedong River Basin,the Democratic People’s Republic of Korea

The macaque fossils, including mandible fragments, were discovered for the first time from the Taedong River Basin around Pyongyang (TRBP) (the Chongphadae Cave, Hwangju County; the Taehung Cave, Sangwon County; the Maeri Cave, Sungho County), the Democratic People’s Republic of Korea, which represent the first recognized occurrences of fossil M. mulatta in DPRK. Although the only available skull specimens are the mandible including the teeth, the materials display some mandibular and dental feature combinations that might belong to the known species of Macaca mulatta. This discovery indicates that TRBP may be the richest area of Macacina fossils and an evolutionary center for macaques in DPRK. Radiometric dating of the Chongphadae Cave sediment Layer 12 and Layer 13 yielded 34770–27800 and 24980–21340 cal yr BP respectively.