Phylogeny and zoogeography of the cyprinid genus Epalzeorhynchos Bleeker (Cyprinidae : Ostariophysi)

A total of 62 variable osteological and external characters was found among the five currently recognized species of Epalzeorhynchos. When the genera Crossocheilus and Paracrossocheilus are combined as the outgroup, only 30 of these characters can be polarized. This includes six autapomorphies. The remaining 24 polarized characters form a data matrix which yields a single, 26-step tree with a Consistency Index (CI) of 1 and a Retention Index (RI) of 1, The analysis was also performed on a combined dataset in which the 32 unpolarized characters (characters for which the combined outgroup was dimorphic) were added and coded as missing data (i.e., "?"), Analyzing this data matrix with all multistate characters ordered generates the same single most-parsimonious tree with a length of 63 steps, a CI of 0.98 and a RI of 0.97, When either Crossocheilus or Paracrossocheilus is used as the sole outgroup, the same single most-parsimonious tree is produced although the numbers of informative characters and some of the polarities differ. Evidence is presented to support the following hypotheses: (1) E, kalopterus + E, frenatus + E. bicolor + E. munensis form a monophyletic group; (2) E. frenatus + E, bicolor + E, munensis form a monophyletic group with E, kalopterus as its sister group; this speciation event is congruent with the predictions of vicariant speciation mode I; and (3) E. bicolor and E. munensis are sister groups, again congruent with vicariant speciation mode I, Evidence presented here also supports the zoogeographical hypothesis that the faunas of the Indochinese region and the Greater Sundas are more closely related to each other than either of them is to the lower Salween basin fauna and that the lower Mekong, Chao Phraya, and Mac Khlong basin faunas are more closely related to each other than any of them is to the Greater Sundas, In addition, the monophyly of Epalzeorhynchos is also preliminarily discussed by including either Paracrossocheilus or Crossocheilus in the ingroup. It is demonstrated that E. bicornis clusters with Paracrossocheilus when Paracrossocheilus is included in the ingroup. It seems likely that the taxonomic position of E. bicornis will be resolved as more fishes of the Crossocheilus group are included in future studies.

外来种紫茎泽兰对入侵地土壤动物群落及多样性的影响

在云南省澜沧县对草地、以紫茎泽兰群落以及次生林地中的土壤动物一步甲和蚯蚓群落进行动态取样调查，来探讨紫茎泽兰入侵后对群落结构、生物多样性的影响。 在紫茎泽兰和草地群落中共捕获2253头步甲，35个种，其中草地上捕获1574头步甲，28个种，紫茎泽兰样地中有679头步甲，34个种;紫茎泽兰群落中步甲个体数量少，但物种数多，多样性也比较高;草地中步甲优势物种为Harpalus indicus和Tetragonoderus arcuatus占总数的59％;而紫茎泽兰中的优势物种比较分散;紫茎泽兰群落中步甲个体体型较大，而草地中体型小的步甲所占比例较高;步甲分布与落叶层厚度、土壤全磷含量、植被高度、地上生物量及土壤pH和土壤全钾含量有一定的相关性;紫茎泽兰群落与草地中的指示物种也不同，Hyphaereon masumotoi和Cosmodiscus sp．是紫茎泽兰的指示物种，而草地的指示物种有Aephnidius adelioides，Tetragonoderus arcuatus，Harpalus indicus，Harpaliscus birmanicus，Chlaenius cambodiensi。 受紫茎泽兰入侵的林地边缘步甲群落的分布规律表明，步甲个体数量排序：林地内部>紫茎泽兰群落>林地边缘：三者步甲优势种的组成，既有交叉也有区别;三者的步甲物种数及多样性指数差异不显著，步甲群落的时间动态也相似;林地边缘、内部及紫茎泽兰群落在步甲个体体型结构上差异不大，具有指示作用的步甲种少。 在草地、紫茎泽兰及次生林地三种植被类型中，共采集到3546条蚯蚓，8个种。其中，紫茎泽兰群落有1663条蚯蚓，远高于次生林及草地。多裂远盲蚓和娇小远盲蚓是当地蚯蚓群落的优势种;紫茎泽兰入侵地的蚯蚓物种数、Shannon-Wiener多样性指数大于草地及次生林地;蚯蚓数量及生物量的时间动态受月份降雨量的影响很大，体型大小不同的蚯蚓受降雨变化影响的程度不同：蚯蚓的分布与落叶层厚度、土壤全氮含量、土壤pH及有机质含量相关性较强;蚯蚓群落中只有大唇远盲蚓是紫茎泽兰样地中的指示物种。 在紫茎泽兰控制实验样地内，步甲的数量及物种数的排序是原始紫茎泽兰>半密度紫茎泽兰>去除处理。优势物种都为Anisodactylus karennius，所占比例高，其在原始紫茎泽兰群落中的分布数量远高于半密度及去除样地;步甲群落多样性指数(H’)和物种数差异不显著;三种处理的步甲群落时间动态不同，表现出不同的高峰期;Galeritula feoe和Nanodiodes piceus是原始和半密度紫茎泽兰样地中的指示物种。 总之，紫茎泽兰入侵相对单一草地后，会引起步甲个体数量下降，物种数和多样性上升，群落结构发生很大变化;紫茎泽兰入侵的林地边缘及外部草地后，林地边缘的环境变化幅度减小，林地的边际效应趋于不明显;紫茎泽兰单优群落有利于蚯蚓生存于生活，与草地及林地相比，能增加蚯蚓鲜重及多样性水平。

瑞丽江流域鱼类组成、区系及生活史特点研究

于2003年9月、2006年4月和11月,分别对瑞丽江流域鱼类资源进行了3次实地调查,共采集到鱼类49种,其中包含1个鱼类属级新纪录及新种——小眼小波鱼(Microrasbora microphthalma)。结合历史资料及文献整理,瑞丽江共有鱼类60种,隶属8目、19科、44属;其中,伊洛瓦底江水系特有鱼类16种,外来引入种9种。鱼类组成上,以鲤科鱼类最多,有26种,占总种数的43.3%;其次为鮡科,有11种,占总种数的18.3%。瑞丽江鱼类区系以喜温的"第三纪类群"中的山区鱼类为主要成分,上游杂有耐高寒的"青藏高原类群"成分,下游杂有热带江河平原鱼类。从生境、生活水层及食性探讨了瑞丽江鱼类生活史特点,并简要分析了鱼类的受危因素并提出了相应的保护建议。

A broad deglacial delta C-13 minimum event in planktonic foraminiferal records in the Okinawa Trough

The equatorial Pacific upwelling zone has been suspected of playing an important role in the global atmospheric CO2 changes associated with glacial-interglacial cycles. In order to assess the influencing scope of the surface water deglacial delta(13)C minimum in the tropical low-latitude Pacific, the core DGKS9603, collected from the middle Okinawa Trough, was examined for 4513 C records of planktonic foraminifera N. dutertrei and G. ruber. The planktonic foraminiferal delta(13)C records show a clear decreasing event from 20 to 6 cal. kaBP., which is characterized by long duration of about 14 ka and amplitude shift of 0.4 x 10(-3). Its minimum value occurred at 15.7 cal kaBP. The event shows fairly synchrony with the surface water deglacial delta(13)C minimum identified in the tropical Pacific and its marginal seas. Because there is no evidence in planktonic foraminiferal fauna and 45180 records for upwelling and river runoff enhancement, the broad deglacial delta(13)C minimum event in planktonic foraminiferal records revealed in core DGKS9603 might have been the direct influencing result of the deglacial surface water of the tropical Pacific. The identification for the event in the Okinawa Trough provides new evidence that the water evolution in the tropical low-latitude Pacific plays a key role in large regional, even global carbon cycle.

甘肃临夏盆地龙担剖面晚新生代磁性地层与古环境

Linxia Basin, situated in the northeast belt of the Tibetan Plateau, is a late Cenozoic depression basin bounded by the Tibetan Plateau and the Chinese Loess Plateau. The Cenozoic deposition, spanning over 30Ma, in which very abundant mammal fossils were discovered, is very suitable for study of uplift processes and geo-morphological evolution of the Tibetan Plateau. The Longdan section (35°31′31.6″N，103°29′0.6″E) is famous for the middle Miocene Platybelodon fauna and the late Miocene Hipparion fauna for a long time and is also one of the earliest known places for wooly rhino, which lies on the east slope of Longdan, a small village of township Nalesi in the south of the Dongxiang Autonomous County, Linxia Hui Nationallity Autonomous Prefecture. The Longdan mammal fauna was discovered at the base of the Early Pleistocene loess deposits at Dongxiang, where the lithology is different from the typical Wucheng Loess on the Chinese Loess Plateau. The rich fossils contain many new species and the major two layers of fossils are in the loess beds. Geologically the fossiliferous area is located in the central part of the Linxia Cenozoic sedimentary basin. Tectonically the Linxia Basin is an intermountain fault basin, bordered by the Leijishan major fault in the south and the north Qinling and Qilianshan major faults in the north. The section is 51.6m thick above the gravel layer, including the 1.6m Late Pleistocene Malan Loess on the top and the other loess-paleosol sequences in the middle of the section. The base of the section is the Jishi Formation, consisting of gravel layer of 13 ~ 17m thick. In this study, 972 bulk samples were collected with an interval of 5cm and other 401 orientied samples were taken with a magnetic compass. In the laboratory, the paleomagnetism, medium grain size, susceptibility, color, micromorphology, anisotropy of magnetic susceptibility were analyzed. From the stratigraphic analysis, the Longdan section from the top 0.3m to the bottom 51.6m, containing 5 normal polarities (N1-N5) and 5 reversal polarities (R1-R5). The paleomagnetic results show N3 is the Olduvai subchron in the middle of the Matuyama chron, and then the chronology of the Longdan mammal fauna is constructed along the section. The Matuyama-Gauss boundary is 45m and N5 enters Gauss chron. The Olduvai subchron with the age of 1.77 ~ 1.95Ma is found just in the upper fossiliferous level of Longdan mammal fauna. Taking the deposit rate of the section into account, the geological age of the upper fossiliferous level of Longdan mammal fauna is estimated to be about 1.9Ma. The lower fossiliferous level is just below the Reunion subchron and its age is estimated to be 2.25Ma. In addition, anisotropy of magnetic susceptibility of the loess-paleosol and other climatic indexes were used for discussing the late Cenozoic paleoenvironmental changes at Longdan, from which the Longdan area should have been an area of predominantly steppe the same as the Longdan mammal fauna.