宁夏、内蒙古的一些早白垩世珠蚌类

宁夏六盘山群上部和内蒙古赛汉塔拉组产出的珠蚌类化石为首次描述,其面貌与邻区相当地层产出的蚌类相似,前人将它们鉴定为Unio。现据它们的壳顶区缺双带构造、前假主齿乳头状并不呈“多”形排列和前闭壳肌痕内具树枝状构造等特征建立Ningxiaconcha gen. nov.。本文还对Pseudelliptio属及其模式种的含义作了补充修订;通过这些珠蚌类化石的对比,宁夏六盘山群和内蒙古赛汉塔拉组可与新疆吐谷鲁群中上部、辽西沙海组和阜新组、山东蒙阴群中上部、浙江寿昌组上段以及苏联、蒙古、德国韦尔登阶进行对比,其时代应归入早白垩世早期。     

内蒙古科尔沁草原绵羊不同虫龄土耳其斯坦东毕吸虫及虫卵孵化的实验观察

作者在内蒙科尔沁草原实验观察了绵羊体内62日龄及三年龄的土耳其斯坦东毕吸虫雌雄虫。三年龄虫体变小,大多数雄虫的睾丸内质呈不同程度空泡伏,部分雌虫的卵巢和卵黄腺萎缩或消失,体形变异。实验羊粪便的虫卵孵化率逐年下降,粪便散入水中后连续4—5天有毛蚴孵出,毛蚴数最多的是在次日上午,随后每天上午有一递减的小高峰,下午极少、夜间消失。     

Modeling grassland aboveground biomass using a pure vegetation index

Remote sensing can be the most effective means of scaling up grassland aboveground biomass (AGB) from the sample scale to the regional scale. Among the remote-sensing approaches, statistical models based on the vegetation index (VI) are frequently used to retrieve grassland AGB because of their simplicity and reliability. However, these types of models have never been comprehensively optimized to overcome VI insensitivity and soil effects. Because grassland AGB is related to grassland type, in our research the integrated orderly classification system for grassland (IOCSG) was used to differentiate grassland types. The study area, located in Inner Mongolia, China, included desert steppe, typical steppe and meadow steppe. A pure VI (PVI) was extracted from the normal VI using spectral mixture analysis (SMA). Using a proportional relationship, PVI models were then constructed based on grassland type. The results demonstrated that the PVI models can have clear advantages over the more commonly used VI models. They simplify the parameterization of VI models and thus enhance models constructed for different regions with different remote sensing data sources. Notably, detailed differentiation of grassland types can improve the accuracy of AGB estimates. The methodology proposed in this study is particularly beneficial for AGB estimates at a national scale, especially for countries such as China with many grassland types.     

Spectrum structures and biological functions of 8-mers in the human genome

The spectra of k-mer frequencies can reveal the structures and evolution of genome sequences. We confirmed that the trimodal spectrum of 8-mers in human genome sequences is distinguished only by CG2, CG1 and CG0 8-mer sets, containing 2,1 or 0 CpG, respectively. This phenomenon is called independent selection law. The three types of CG 8-mers were considered as different functional elements. We conjectured that (1) nucleosome binding motifs are mainly characterized by CG1 8-mers and (2) the core structural units of CpG island sequences are predominantly characterized by CG2 8-mers. To validate our conjectures, nucleosome occupied sequences and CGI sequences were extracted, then the sequence parameters were constructed through the information of the three CG 8-mer sets respectively. ROC analysis showed that CG1 8-mers are more preference in nucleosome occupied segments (AUC > 0.7) and CG2 8-mers are more preference in CGI sequences (AUC > 0.99). This validates our conjecture in principle.     

长爪沙鼠的贮食行为与其个性和代谢水平之间的关系

贮食行为是动物应对食物资源的季节性和不可预测性变化的一种适应性生存策略。在群居性贮食动物中,同胎个体常表现出不同的贮食水平,而关于贮食行为与动物的个性和代谢水平之间的关系尚缺乏研究。本文以长爪沙鼠（Meriones unguiculatus）为对象,在筛选出具有高贮食和低贮食行为特征个体的基础上,比较了两组动物的个性特征（勇敢行为和探索能力）、静止代谢率、血清甲状腺激素水平、贮食期间的运动距离和贮食后的平均每日代谢率等。结果发现：高、低贮食长爪沙鼠的数量各占49%（22/45）和47%（21/45）,两组动物之间的个性特征、静止代谢率和血清甲状腺激素均没有显著差异。在贮食期间高贮食个体的运动距离显著高于低贮食个体,且在停止贮食后,高贮食个体的平均每日代谢率显著低于低贮食个体。这些结果表明,在室内条件下,长爪沙鼠的贮食量高低与个性和静止代谢率无关,但高贮食个体会在停止贮食后降低其总能量消耗,以补偿贮食过程中的高能量代价。     

A late early to early middle Eocene mammal assemblage from Bayan Ulan (Inner Mongolia,China): Implication for the reassessment of the Arshantan Asian Land Mammal Age

Paleogene mammal localities of North China are particularly well represented in the Erlian Basin, Inner Mongolia. Among them, the locality of Bayan Ulan is most famous for its late Paleocene Gashatan fauna. However, the younger Arshantan fauna of the same site is not well known, since no extensive study has been done so far. Here, we present a small mammal assemblage based on dental and tarsal material from a new Arshantan collection retrieved from the red beds of the late early to early middle Eocene Arshanto Formation at Bayan Ulan. It consists of at least six different taxa: the basal lagomorph Dawsonolagus antiquus, the large pantodont Pantolambdodon sp., the tapiroid Schlosseria magister, and the rhinocerotoids Hyrachyus crista and Rhodopagus guoi nov. sp. The assemblage is dominated by perissodactyls, especially Lophialetidae and Hyracodontidae. For the first time, p4-m1 of Dawsonolagus antiquus, tarsal material from Pantolambdodon sp., and lower dentition and tarsals of Hyrachyus crista are described and illustrated. Unlike other described Arshantan faunas, the Bayan Ulan Arshantan mammal assemblage has been collected exclusively from a single locality, which contributes to the reassessment of the misunderstood Arshantan Asian Land Mammal Age.     

A hydroclimatic regionalization of central Mongolia as inferred from tree rings

In arid and semi-arid regions of the world, such as Mongolia, the future of water resources under a warming climate is of particular concern. The influence of increasing temperatures on precipitation is difficult to predict because precipitation trends in coming decades could have a high degree of spatial variability. In this study, we applied a rotated principal component analysis (RPCA) to a network of 20 tree-ring chronologies across central Mongolia from 1790 to 1994 to evaluate spatial hydroclimatic variability and to place recent variability in the context of the past several centuries. The RPCA results indicate that the network consists of four tree-growth anomaly regions, which were found to be relatively stable through time and space. Correlation analyses reveal spatial linkages between the tree-growth anomalies and instrumental data, where annual streamflow variability was strongly associated with tree-growth anomalies from their respective regions from 1959 to 1994 (r = 0.52–0.64, p < 0.05). This study highlights the extent of spatial variability in hydroclimate across central Mongolia and emphasizes the value of using tree-ring networks in locations with limited instrumental records.     

Dietary adaptations and palaeoecology of Lophialetidae (Mammalia,Tapiroidea) from the Eocene of the Erlian Basin,China: combined evidence from mesowear and stable isotope analyses

Lophialetidae is an extinct group of endemic Asiatic tapiroids that are widely distributed in the Eocene sediments of Asia. Schlosseria magister and Lophialetes expeditus are the most abundant species in this family. However, their dietary and ecological characteristics are largely unknown. For the first time, we reconstruct the palaeodiet and habitat of these two lophialetids using a combination of mesowear and stable carbon isotope analysis of fossil teeth excavated from the Erlian Basin, China. Mesowear analysis (n = 141) suggests that the dietary structure of S. magister and L. expeditus shifted from less to more abrasive diets from ~52 to ~42 Ma. Stable carbon isotope analysis (n = 137) suggests that the habitats of S. magister and L. expeditus became drier and/or more open through time. The dietary shifts of the two lophialetids are consistent with evident changes in habitat. The changes in the diet and habitat were probably related to global climate change during that time period. The gradual drop in global temperatures during the early–middle Eocene led to a drier and more open terrestrial ecosystem in the Erlian Basin, probably resulting in changes in floral composition of the environment inhabited by S. magister and L. expeditus. Hence, herbivores highly susceptible to vegetation modification had to develop new resource exploitation strategies to adapt to these changes. Schlosseria magister, considered to be the sister-group of L. expeditus and with a low level of ecological flexibility, was unable to adapt to the habitat changes finally becoming extinct at ~45 Ma.     

New fossil hangingflies (Insecta: Mecoptera: Raptipedia: Cimbrophlebiidae) from the Middle Jurassic of Inner Mongolia,China

Abstract: Two new genera with six new species of hangingflies (Mecoptera: Raptipedia: Cimbrophlebiidae) are described. They were collected from the Middle Jurassic nonmarine sedimentary strata of the Jiulongshan Formation in Daohugou, Inner Mongolia, north‐eastern China. This report of Cimbrophlebiidae from the Yanliao Biota provides detailed morphological information and evidence of a broad diversity of Cimbrophlebiidae during the Middle Jurassic. A key to the known species of Cimbrophlebiidae is provided.     

Family Lasiosynidae n. fam., new palaeoendemic Mesozoic family from the infraorder Elateriformia (Coleoptera: Polyphaga)

Lasiosynidae n. fam. is proposed for the genera Lasiosyne Tan, Ren & Chih 2007 (transferred from Archostemata to Polyphaga), Anacapitis Yan 2009 Tarsomegamerus Zhang 2005 (proposed in the superfamily Chrysomeloidea) and Bupredactyla n. gen. The new family is regarded in composition of the infraorder Elateriformia without a more detailed attribution, because it demonstrates a mixture of characters of different families and superfamilies, i.e. somehow an intermediate position between the superfamilies Dascilloidea, Elateroidea, Buprestoidea and Byrrhoidea with most resemblance to Dascillidae, Schizopodidae, Eulichadidae, Ptilodactylidae and Callirrhipidae and probable more close relationship to the last three families. Four new fossil species of the genus Lasiosyne: L. daohugouensis n. sp., L. fedorenkoi n. sp., L. gratiosa n. sp., L. quadricollis n. sp., and also Bupredactyla magna n. sp. are described from the Middle Jurassic Jiulongshan Formation of eastern Inner Mongolia, China. A probable generic composition of the new family is considered. The synonymy of generic names Anacapitis Yan 2009 and Brachysyne Tan & Ren 2009, n. syn. as well as synonymy of species names Lasiosyne euglyphea Tan, Ren & Chih 2007, Pappisyne eucallus Tan & Ren 2009, n. syn. and Pappisyne spathulata Tan & Ren 2009, n. syn. are proposed.