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Abstract: The lacertid material from the locality of Herrlingen 8 (upper Oligocene, MP28) is described as a new species of the genus Plesiolacerta. The material is disarticulated and comprises isolated elements including parietal, frontal, maxilla and dentary. It can be assigned to a single species on the basis of the external surface ornamentation. This morphology is typical for the genus Plesiolacerta, but the material differs in detail from the type species P. lydekkeri. The most significant feature of the new species is that the occipital scute of the parietal bone is narrow, rectangular in shape and anteroposteriorly short. Hitherto, the last occurrence of this genus was in the lower Oligocene. This material represents the first evidence of the existence of this genus in the upper Oligocene. Therefore, our knowledge of its evolution is expanded by providing new data on its spatial and temporal ranges and morphology. This taxon has a much longer history than we thought. In addition, the Eocene species, P. lydekkeri, is reviewed here. P. lydekkeri shares the most lacertid synapomorphies and, given our present knowledge, Plesiolacerta is a taxon very close to or possibly within crown Lacertidae. The frontal and postorbitofrontal of Plesiolacerta are described for the first time. In view of the primitive morphology and early occurrence of Plesiolacerta, it seems that the feature of a longer anterior region of the frontal could be considered as a plesiomorphic feature within lacertid lizards, and the condition in Timon (approximately the same length) as derived. 相似文献
53.
NEIL H. LANDMAN JEAN LOUIS DOMMERGUES DIDIER MARCHAND 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1991,24(4):409-421
Several examples of progenetic species among Mesozoic ammonites are investigated. The ammonites are Middle Jurassic kosmoceratids, Upper Jurassic oppeliids, and Upper Cretaceous scaphites. As assessed through outgroup comparison, the progenetic species in each of these examples is characterized by small size at maturity and the presence of morphological features typical of those of the juveniles of more primitive species. However, in none of these examples is the progenetic species a duplicate form of the juvenile stage of more primitive species. There are at least three kinds of features of progenetic species that differ from those of the juveniles of more primitive species: (1) symplesiomorphous features associated with maturation, (2) unique features whose presence is not clearly related to progenetic processes, and (3) unique features that may represent epigenetic outgrowths of juvenile morphology. This novel combination of juvenile. adult. and unique features may endow progenetic species with the evolutionary potential to play a role in the origin of higher taxa. □ Progenesis, heterochrony, Ammon-oidea. Jurassic, Cretaceous. 相似文献
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Efficient methods for constructing 16S tag amplicon libraries for pyrosequencing are needed for the rapid and thorough screening of infectious bacterial diversity from host tissue samples. Here we have developed a double‐nested PCR methodology that generates 16S tag amplicon libraries from very small amounts of bacteria/host samples. This methodology was tested for 133 kidney samples from the lake whitefish Coregonus clupeaformis (Salmonidae) sampled in five different lake populations. The double‐nested PCR efficiency was compared with two other PCR strategies: single primer pair amplification and simple nested PCR. The double‐nested PCR was the only amplification strategy to provide highly specific amplification of bacterial DNA. The resulting 16S amplicon libraries were synthesized and pyrosequenced using 454 FLX technology to analyse the variation of pathogenic bacteria abundance. The proportion of the community sequenced was very high (Good’s coverage estimator; mean = 95.4%). Furthermore, there were no significant differences of sequence coverage among samples. Finally, the occurrence of chimeric amplicons was very low. Therefore, the double‐nested PCR approach provides a rapid, informative and cost‐effective method for screening fish immunobiomes and most likely applicable to other low‐density microbiomes as well. 相似文献
56.
LOUIS P. RONSE DE CRAENE fls ELSPETH HASTON 《Botanical journal of the Linnean Society. Linnean Society of London》2006,151(4):453-494
A cladistic analysis is performed using 94 morphological and biochemical characters for 42 genera to compare a phylogeny based on morphological data with those obtained using different genes ( rbc L, atp B, 18S RNA, mat K) or their combination with morphological data, and to understand the floral evolution within the expanded Brassicales (Capparales) relative to Sapindales and Malvales. The tree produced with morphological data is congruent with those obtained from macromolecular studies in obtaining a well-supported glucosinolate-producing clade and an expanded Sapindales. The combined analysis of the morphological and molecular characters is generally well resolved with support for many of the relationships. The inclusion of the fossil taxon Dressiantha demonstrates the value of inserting fossil evidence in phylogenetic analyses. However, the fossil appears to be related to the Anacardiaceae and not to the Brassicales. The core Brassicales are well supported by a number of synapomorphies, although the internal position of Tovariaceae and Pentadiplandraceae is not well resolved. Emblingiaceae appears to be related to Bataceae and Salvadoraceae. Several significant morphological characters are mapped on the combined trees and their evolutionary significance is discussed. Within Brassicales and Sapindales several well supported clades can be recognized which merit ordinal or subordinal status, putting the present orders at a higher level; these include: Tropaeolales, Setchellanthales, Batidales, Brassicales (Brassiciflorae), Burserales, Sapindales and Rutales (Sapindiflorae). The present scheme of affinities within the Brassicales corresponds well with a gradual morphological evolution in the order. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 453–494. 相似文献
57.
Nitrogen oxide gas emissions from temperate forest soils receiving long-term nitrogen inputs 总被引:8,自引:0,他引:8
RODNEY T. VENTEREA PETER M. GROFFMAN LOUIS V. VERCHOT† ALISON H. MAGILL‡ JOHN D. ABER‡ PAUL A. STEUDLER§ 《Global Change Biology》2003,9(3):346-357
From spring 2000 through fall 2001, we measured nitric oxide (NO) and nitrous oxide (N2O) fluxes in two temperate forest sites in Massachusetts, USA that have been treated since 1988 with different levels of nitrogen (N) to simulate elevated rates of atmospheric N deposition. Plots within a pine stand that were treated with either 50 or 150 kg N ha?1 yr?1 above background displayed consistently elevated NO fluxes (100–200 µg N m?2 h?1) compared to control plots, while only the higher N treatment plot within a mixed hardwood stand displayed similarly elevated NO fluxes. Annual NO emissions estimated from monthly sampling accounted for 3.0–3.7% of N inputs to the high‐N plots and 8.3% of inputs to the Pine low‐N plot. Nitrous oxide fluxes in the N‐treated plots were generally < 10% of NO fluxes. Net nitrification rates (NRs) and NO production rates measured in the laboratory displayed patterns that were consistent with field NO fluxes. Total N oxide gas flux was positively correlated with contemporaneous measurements of NR and concentration. Acetylene inhibited both nitrification and NO production, indicating that autotrophic nitrification was responsible for the elevated NO production. Soil pH was negatively correlated with N deposition rate. Low levels (3–11 µg N kg?1) of nitrite () were detected in mineral soils from both sites. Kinetic models describing NO production as a function of the protonated form of (nitrous acid [HNO2]) adequately described the mineral soil data. The results indicate that atmospheric deposition may generate losses of gaseous NO from forest soils by promoting nitrification, and that the response may vary significantly between forest types under similar climatic regimes. The lowering of pH resulting from nitrification and/or directly from deposition may also play a role by promoting reactions involving HNO2. 相似文献
58.
LOUIS C. BENDER LAURIE A. LOMAS JASON BROWNING 《The Journal of wildlife management》2007,71(4):1118-1124
Abstract: From December 2001 to December 2004 we monitored 30–44 adult female mule deer (Odocoileus hemionus) annually to assess the factors affecting survival and cause-specific mortality. We found adult female survival of 0.63 (SE = 0.08), 0.90 (SE = 0.05), and 0.91 (SE = 0.04), 2002–2004, respectively. Starvation was the most common cause of mortality, accounting for 11/23 mortalities. Mean ingesta-free body fat (IFBF) levels of adult females in December were low (6–9%), despite few (0–13%) lactating adult females, indicative of extremely nutritionally deficient summer—autumn ranges throughout the study site. A priori levels of IFBF and rump body condition scores (rBCS) were higher in deer that survived the following year regardless of cause of mortality. Logistical analysis indicated that models containing individual body fat, rBCS, mean population body fat, winter precipitation, precipitation during mid- to late gestation, and total annual precipitation were related (x2 ≥ 9.1; P ≤ 0.003) to deer survival, with individual IFBF (β =-0.47 [SE = 0.21]; odds ratio = 0.63 [0.42-0.94]) and population mean IFBF (β = -1.94 [SE = 0.68]; odds ratio = 0.14 [0.04-0.54]) the best predictors; with either variable, probability of dying decreased as fat levels increased. Fawn production was low (2–29 fawns/100 ad F) and, combined with adult survival, resulted in estimated population rates of increase of -35%, -5%, and +6% for 2002–2004, respectively. Deer survival and population performance were limited in north-central New Mexico, USA, due to poor condition of deer, likely a result of limited food resulting from both drought and long-term changes in plant communities. Precipitation during mid- to late gestation was also important for adult female survival in north-central New Mexico. 相似文献
59.
LOUIS R. SULLIVAN 《American anthropologist》1917,19(3):406-409
60.
JAMES G. JOHNSON NAVA EPSTEIN TSUGIYE SHIROISHI LOUIS H. MILLER 《The Journal of eukaryotic microbiology》1981,28(2):160-164
Viable merozoites of Plasmodium knowlesi were isolated and the proteins that were labeled on intact merozoites by lactoperoxidase-catalyzed radioiodination were identified. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography of Triton soluble extracts of labeled merozoites demonstrated eight major bands ranging in apparent molecular weight from 150,000 D to 22,000 D. Exposure of intact merozoites to trypsin (10 μg/ml) for 10 min resulted in the loss of the two highest molecular weight proteins (150,000 D and 105,000 D) and the appearance of two new bands at 70,000 D and 62,000 D. Trypsin treatment under these conditions also removed the receptor(s) for merozoite attachment to erythrocytes. Therefore, these high molecular weight proteins are candidates for the merozoite component that attaches to erythrocytes. There was no evidence that the labeled membrane components were serum or erythrocyte membrane components, two potential contaminants in the preparation. Anti-rhesus erythrocyte antibody did not precipitate labeled merozoite proteins. Furthermore, the immunoprecipitation of labeled merozoite proteins by rhesus anti-merozoite serum was not inhibited by erythrocyte ghosts. 相似文献