伤齿龙标本IVPP V 10597分类学重新讨论(英文)

保存部分后肢的标本 IVPP V 10597 最初被描述为蒙古蜥鸟龙(Saurornithoides mongoliensis) 的幼年个体,但存在一些疑问。近年来有关伤齿龙科(Troodontidae) 的研究,尤其是有关伤齿龙类分类学研究取得了重要进展,因此有必要对该标本的分类学重新进行评估。通过细致的形态比较和数值化的系统发育分析,确认相对于蒙古蜥鸟龙,V 10597 更加接近于同域的谭氏临河猎龙(Linhevenator tani) ,指示其有可能代表谭氏临河猎龙的幼年个体。但 V 10597 的许多后肢特征,包括许多涉及后肢骨骼间比例的特征,显示出与包括谭氏临河猎龙在内的其他伤齿龙类的明显区别。这些形态差异可能具有分类学意义,表明 V 10597 代表一个新种。通过骨组织学分析,确认该标本不可能代表谭氏临河猎龙或者其他大型伤齿龙类的幼年个体。基于已有的形态学和骨组织学信息,将 V 10597 定为一新属、新种,命名为柯瑞氏菲利猎龙(Philovenator curriei gen. et sp. nov. ) 。这一发现增加了白垩纪晚期伤齿龙类的种群分异度和形态差异度。     

Evaluation of Total Body Electrical Conductivity to Estimate Body Composition of a Small Mammal

ABSTRACT The ability to measure body composition is critical for studying the physiological ecology of animals. This is particularly true for small mammals that have a high metabolic rate. We evaluated a nondestructive method of body composition analysis that would allow accurate assessment of body fat, body water, and lean mass. We used total body electrical conductivity (TOBEC) to estimate body composition in the little brown myotis (Myotis lucifugus). In a sample of 46 individuals, TOBEC was both accurate and precise in estimating total body water and lean mass but was less effective at estimating total body fat. Mass-independent or whole-body compartments (i.e., total body water, total body fat, lean dry mass, and lean body mass) were more accurately estimated than mass-dependent or mass-specific body composition compartments (i.e., water content, fat index, and % lean dry mass). The TOBEC measurements we made using an SA-3000 analyzer were influenced by extremes in body temperature, as well as by aluminum and incoloy wing bands. Our study also presents a new method of restraint especially suited for small mammals and birds that increases precision of TOBEC measurements. This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.     

Detectability of American Mink Using Rafts to Solicit Field Signs in a Population Control Context

Abstract: American mink (Neovison vison) are an ecologically damaging invasive species where they have been introduced in Europe. Effectiveness of mink population control by trapping has been difficult to assess, without knowing how efficiently mink are caught by traps or detected by other methods. Use of track-recording rafts to detect mink and guide trapping effort has proved efficient and leads to a supposition that no detection indicates absence of mink. To draw this conclusion with any confidence requires a measure of detectability. We applied occupancy models to data from an earlier study to estimate detectability of individual American mink on track-recording rafts. Estimated detectability of individual mink, per raft, and 2-week check period varied between 0.4 in late summer and 0.6 in late autumn. By inference, risk of failing to detect a mink that was present would be <5% given 4–6 independent opportunities to detect it. These opportunities could be created either by using a raft spacing that ensured multiple detections of each mink or by monitoring rafts through a succession of check intervals. Within certain simple constraints, raft location did not contribute substantially to detection probability. These findings will allow field operators, strategists, and funders to assess with confidence the success of efforts to control mink density. We expect the estimation of individual detectability to be similarly valuable in population control or eradication of other species.     

The Changing State of Surfactant Lipids: New Insights from Ancient Animals

SYNOPSIS. Pulmonary surfactant is a mixture of phospholipids(including disaturated phospholipids), cholesterol and proteinslining the air-liquid interface within the lung. Surfactantacts to reduce surface tension, thereby increasing lungcomplianceand also preventing edema. The saccular lungs, or other gas-holdingstructures, of nonmammals have 7–70% more surfactant/cm²of surface than lungs of mammals. Nonmammalian surfactant actsas an antiglue that decreases the inflation pressures of collapsedlungs by reducing the adherence of apposing epithelial surfaces.The autonomic nervous system appears to be the primary systemcontrolling release of surfactant in nonmammals. The lipid compositionis highly conserved within the vertebrates, except that surfactantof teleost fish is dominated by cholesterol whereas tetrapodsurfactant consists primarily of disaturated phospholipids (DSP).The dipnoan Neoceratodus forsteri demonstrates a "fish-type"surfactant profile while the other derived dipnoans demonstratea surfactant profile similar to that of tetrapods. Homologyof the surfactant protein SP-A within the vertebrates pointsto a single evolutionaryorigin for the system and indicatesthat fish surfactant is a "protosurfactant". Amongst the tetrapods,the relative proportions of DSP and cholesterol vary in responseto lung structure, habitat, and body temperature (T_b) but notin relation to phytogeny. The cholesterol content of surfactantis elevated in species with simple saccular lungs, in aquaticspecies, and in species with low T_b. The DSP content is highestin complex lungs, particularly ofaquatic species or specieswith high T_b. The cholesterol content of surfactant also increasesin response to acute decreases in Tb in lizards and torpid marsupials,presumably to maintain fluidity of the lipid mixture.     

Influence of ultraviolet-B (UV-B) radiation on photosynthetic and growth characteristics in field-grown cassava (Manihot esculentum Crantz)

The effects of ultraviolet-B (UV-B between 290 and 320 nm) on photosynthesis and growth characteristics were investigated in field grown cassava (Manihot esculentum Crantz). Plants were grown at ambient and ambient plus a 5.5kJ m^?2 d^?1 supplementation of UV-B radiation for 95 d. The supplemental UV-B fluence used in this experiment simulated a 15% depletion in stratospheric ozone at the equator (0°N). Carbon dioxide exchange, oxygen evolution, and the ratio of variable to maximum fluorescence (F_v/F_m) were determined for fully expanded leaves after 64–76 d of UV-B exposure. AH plants were harvested after 95 d of UV-B exposure, assayed for chlorophyll and UV-B absorbing compounds, and separated into leaves, petioles, stems and roots. Exposure to UV-B radiation had no effect on in situ rates of photosynthesis or dark respiration. No difference in the concentration of UV-B absorbing compounds was observed between treatments. A 2-d daytime diurnal comparison of F_v to F_m ratios indicated a significant decline in F_v/F_m ratios and a subsequent increase in photoinhibition under enhanced UV-B radiation if temperature or PPF exceeded 35°C or 1800μmol m^?2 s^?1, respectively. However, UV-B effects on fluorescence kinetics appeared to be temporal since maximal photosynthetic rates as determined by oxygen evolution at saturated CO₂ and PPF remained unchanged. Although total biomass was unaltered with UV-B exposure, alterations in the growth characteristics of cassava grown with supplemental UV-B radiation are consistent with auxin destruction and reduced apical dominance. Changes in growth included an alteration of biomass partitioning with a significant increase in shoot/root ratio noted for plants receiving supplemental UV-B radiation. The increase in shoot/root ratio was due primarily to a significant decrease in root weight (–32%) with UV-B exposure. Because root production determines the harvest-able portion of cassava, UV-B radiation may still influence the yield of an important tropical agronomic species, even though photosynthesis and total dry biomass may not be directly affected.     

Hydrological connectivity drives patterns of macroinvertebrate biodiversity in floodplain rivers of the Australian wet /dry tropics

1. Floodplain rivers in Australia's wet/dry tropics are regarded as being among the most ecologically intact and bio-diverse lotic ecosystems in the world, yet there have been relatively few community-based studies of their aquatic fauna.
2. To investigate relationships between hydrological connectivity and biodiversity in the region, macroinvertebrates were collected from sites within two contrasting floodplain rivers, the 'tropical' Gregory River and 'dryland' Flinders River systems, during the dry season and analysed at various spatial scales. A subset of sites was re-sampled in the following dry season to explore temporal variation. The fauna consisted of 124 morphotaxa, dominated by gatherers and the Insecta.
3. As predicted, hydrological connectivity (the lotic or lentic status of waterbodies) had a major influence on macroinvertebrate assemblage composition and diversity, both in space and time. Assemblages from waterbodies with similar connection histories were most alike, and beta-diversity between assemblages was greatest between lotic and lentic waterbodies, tending to increase with increasing spatial separation.
4. At smaller spatial scales, a number of within-waterbody, habitat and water quality characteristics were important for explaining variation (61%) in the taxonomic organization of assemblages, and characteristics associated with primary productivity and habitat diversity were important for explaining variation (45%) in the functional organization of assemblages. However, much of the small-scale environmental variation across the study region appeared to be related to broad-scale variation in hydrological connectivity, which had both direct and indirect effects on macroinvertebrate assemblages.
5. Conservation of the biodiversity in Australia's wet/dry tropics may depend on conserving the natural variation in hydrological connectivity and the unregulated flow of floodplain rivers.