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21.
Burmaneura minuta gen. et sp. nov., the first araripeneurine antlion in amber, is characterized, described and compared with the modern and Mesozoic Myrmeleontidae. The precise position of the fossil within this group is debatable. Interestingly, despite a rather rich fossil record, all Mesozoic Myrmeleontidae belong to subfamilies that are not recorded in the Cenozoic, although this might merely reflect the artificiality of the classification as the extinct groups may be paraphyletic with respect to their younger counterparts (e.g., Araripeneurinae may very well be nothing more than a stem group of no classificatory value). 相似文献
22.
Understanding species distributions, and how they change in space and time, is vital when prioritising conservation or management initiatives. We assessed the distribution and density patterns of common dolphins (Delphinus sp.), bottlenose dolphins (Tursiops truncatus) and Bryde’s whales (Balaenoptera edeni) in the Hauraki Gulf, New Zealand. Dedicated boat-based surveys were conducted in the inner Hauraki Gulf (IHG) and off Great Barrier Island (GBI) during 2010–2012. Generalised linear models were used to investigate temporal changes in relative densities and kernel density estimation was implemented to examine spatial trends. Common dolphins were widely distributed during all seasons, with higher densities observed during winter and spring in the IHG but during autumn off GBI. There was inter-annual variation in Bryde’s whale distribution, with high densities recorded off GBI in 2011. Bottlenose dolphins were infrequently sighted in the IHG but regularly encountered off GBI, with the highest densities during spring and summer. 相似文献
23.
拟哲水蚤是莱州湾桡足类中周年出现的优势种;是上层鱼类幼鱼早期开口饵料的重要贡献者;掌握其种群动态分布特点;有利于了解湾内生物环境状况、次级生产力生产水平。基于2011年5月至20 12年4月采集的浮游生物资料的分析结果显示;莱州湾拟哲水蚤的发育期丰度组成和个体大小均表现了明显的季节变化。调查季节中;4-6月以成体居多;其他季节以桡足幼体CⅢ-CⅤ较多;其中10-11月和3月主要由后期桡足幼体CⅣ和CⅤ期构成。成体中以雌体为主导;雌/雄比介于1.46~9.62;该比值在3-4月最低;10-11月最高。拟哲水蚤各期桡足幼体和成体个体大小以4-5月最大、8月最小;并与水温表现出明显的负相关。拟哲水蚤桡足幼体和成体的总生物量月变化与丰度变化相同;即以8月值最高;3-5月值最低;月均值为2.69 mg/m3（以碳计）;日生产力估算值为0.74 mg/（m3·d）（以碳计）。由上述结果;推测莱州湾拟哲水蚤的种群结构周年变化主要可分3个阶段;4-6月是莱州湾拟哲水蚤开始繁殖期;7-8月为种群数量快速增长期;9月之后为种群增长相对停滞期。 相似文献
24.
为寻找天然抗污损活性化合物,以抗硅藻附着活性为导向,采用有机溶剂萃取、半制备高压液相色谱对分离自海绵的芽孢杆菌UST050418-715代谢产物进行分离,纯化抗硅藻附着活性物质,并利用气相色谱-质谱联用仪、核磁共振波谱分析活性物质结构。从菌株UST050418-715代谢产物中分离得到7种具有抗硅藻附着活性的环二肽类化合物,分别鉴定为:(1)环(L-亮氨酸-反式-8-羟基-L-脯氨酸-)、(2)环(L-缬氨酸-L-脯氨酸)、(3)环(D-脯氨酸-L-亮氨酸)、(4)环(L-脯氨酸-D-亮氨酸)、(5)环(甘氨酸-L-脯氨酸)、(6)环(L-苯丙氨酸-顺式-8-羟基-D-脯氨酸-)、(7)环(L-苯丙氨酸-反式-8-羟基-L-脯氨酸-)。说明海绵附生芽孢杆菌UST050418-715代谢产物中存在大量环二肽类化合物,可以帮助宿主海绵实现对硅藻附着的化学防御。 相似文献
25.
Annulipsyllipsocus andreneli gen. et sp. nov. and A. inexspectatus gen. et sp. nov., the first records of the Psyllipsocidae from the Cretaceous amber of Myanmar are described, illustrated and their taxonomic position discussed. The new genus is characterized by antennae with 16 segments; flagellomeres with secondary annulations; radial cell closed, five-angled, bulged on its R1 border; triangular pterostigma. Species belonging to Annulipsyllipsocus gen. nov. are polymorphic. The described taxa represent the earliest evidence for polymorphism in Psocodea. A checklist of all known species of Psyllipsocidae is given. 相似文献
26.
Aspects of communities and events in the concentrating ponds (S.G. 1.130 to 1.214) and salt crystallizing ponds (S.G. 1.215 to 1.264) of solar saltworks pertinent to salt manufacture are described. Communities that aid salt manufacture enable continuous and efficient production of high quality salt at a saltworks' design capacity, and they provide important controls on levels of organic matter in the brine. Fluctuating salinities, high concentrations of nutrients, and petroleum products are disturbances that causeAphanothece halophytica andDunaliella salina to release excessive quantities of organic matter, and that suppress or cause death to nutrient stripping organisms. Disturbances result in decreased quality and quantity of salt and increased costs for salt harvest, washing, and pond upkeep. Organic matter can be controlled by management techniques that keep nutrient stripping communities at proper levels and maintain a narrow and unchanging range of salinities in each pond, by constructing pond dikes able to withstand wind and water erosion, and by preventing spills of petroleum products in the ponds. 相似文献
27.
In certain areas of the Namib gravel plains a new Ariadna sp. was discovered. It rims its vertical burrow with a stone circle, made on average of seven quartz stones. Some mathematical relationships between hole diameter, stone sizes and weight, and animal size were studied. A correlation was found, and stone selection by this spider postulated. Different hypotheses on the adaptive value of stone circle are suggested. 相似文献
28.
光照强度对隐藻吸收铁和磷的影响 总被引：3，自引：0，他引：3
在模拟条件下,通过深入研究光照强度对隐藻生长率的影响,以及不同光照强度下藻细胞对Fe和P的吸收差异,提出了光照强度控制藻细胞对营养元素的吸收,最终限制赤潮藻爆发性增殖的作用途径.研究表明,藻细胞的生长率与光照强度之间呈指数相关关系;隐藻生长的光饱和值与光半饱和值分别为150 μmol/(m2·s)和47 μmol/(m2·s);在低光照强度下藻细胞的生长率较低,但是藻细胞却需要吸收更多的Fe和P,以及Zn、Mn、Co和Mo等微量元素,在光照强度为10 μmol/(m2·s)时,藻细胞生长率仅为光照强度150 μmol/(m2·s)时的十分之一,而藻细胞对Fe和P的吸收量分别提高了1.5倍和1倍.这些研究结果为揭示导致赤潮常在光照良好天气后发生的根本原因提供了全新的认识. 相似文献
29.
Fossil leaves resembling Nothofagaceae have been investigated from the Eocene of western Antarctica and a new form genus Nothofagofolia is proposed for these kinds of fossils. Some new specimens belonging to this form genus are described. They were collected
from the Fossil Hill locality of Fildes Peninsula, King George Island, South Shetland Islands, western Antarctica. Two new
species, two new combinations and an unnamed species are reported. A number of published Nothofagus leaf fossils from the same locality are discussed and revised. As a result of these studies of Nothofagus leaf morphology, we conclude that (1) Nothofagus probably originated in high latitudes of the Southern Hemisphere during the middle-late Late Cretaceous and diversified,
dispersed gradually to the lower latitudes of the same hemisphere; (2) leaf morphological characters are significant for the
systematics of the family Nothofagaceae, especially at the intrageneric level; and (3) extant species of Nothofagus known from southern temperate areas have more primitive leaf morphological characters and lower leaf ranks than those from
tropical mountains as well as those of the Fagaceae and Betulaceae.
Supported by the Foundation of State Key Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology and Palaoentology,
Chinese Academy of Sciences (Grant No. 013106), the National Natural Science Foundation of China (Grant No. 30670159) and
the Fund of Innovation Program by Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences 相似文献
30.