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991.
报道我国园蛛科2新种:阿克苏园蛛Araneus aksuensis,皇冠扇蛛Zilla crown-ia。 相似文献
992.
The objective of this study was to quantify spatial and temporal variability of anguillid glass eel ingress within and between adjacent watersheds in order to help illuminate the mechanisms moderating annual recruitment. Because single fixed locations are often used to assess annual recruitment, the intra-annual dynamics of ingress across multiple sites often remains unresolved. To address this question, plankton nets and eel collectors were deployed weekly to synoptically quantify early stage Anguilla rostrata abundance at 12 sites across two New Jersey estuaries over an ingress season. Numbers of early-stage glass eels collected at the inlet mouths were moderately variable within and between estuaries over time and showed evidence for weak lunar phase and water temperature correlations. The relative condition of glass eels, although highly variable, declined significantly over the ingress season and indicated a tendency for lower condition A. rostrata to colonize sites in the lower estuary. Accumulations of glass eels and early-stage elvers retrieved from collectors (one to >1500 A. rostrata per collector) at lower estuary sites were highly variable over time, producing only weak correlations between estuaries. By way of contrast, development into late-stage elvers, coupled with the large-scale colonization of up-river sites, was highly synchronized between and within estuaries and contingent on water temperatures reaching c. 10−12° C. Averaged over the ingress season, abundance estimates were remarkably consistent between paired sites across estuaries, indicating a low degree of interestuary variability. Within an estuary, however, abundance estimates varied considerably depending on location. These results and methodology have important implications for the planning and interpretation of early-stage anguillid eel surveys as well as the understanding of the dynamic nature of ingress and the spatial scales over which recruitment varies. 相似文献
993.
994.
JONATHAN B. COHEN SARAH M. KARPANTY JAMES D. FRASER BRYAN D. WATTS BARRY R. TRUITT 《The Journal of wildlife management》2009,73(6):939-945
ABSTRACT Weekly counts of western Atlantic red knots (Calidris canutus rufa) at their Delaware Bay migration stopover site have suggested a major decline since the 1980s. We estimated red knot spring passage population size in the New Jersey Coast-Delaware Bay region (DENJ; 2004 and 2006) and Virginia (VA; 2006 and 2007), USA, by correcting weekly aerial counts for mean daily residence probability between counts in a Monte-Carlo simulation. We used daily telemetry relocations in mark-resight models to estimate mean daily residence probability. Average daily residence probability was approximately 1.0 in mid-May, 0.96–0.97 in the week of 22 May, and 0.64–0.77 after May 28 in DENJ in 2004 and 2006 and in VA in 2006. Average daily residency was approximately 0.88 in VA in 2007 from 22 May to 5 June. No birds moved from VA to DENJ in 2006 and only 2 birds (5.5%) moved in 2007. Stopover population sizes (±SE) in DENJ were 17,108 ± 1,322 in 2004 and 19,555 ± 831 in 2006, and in VA were 7,224 ± 389 in 2006 and 8,332 ± 718 in 2007, significantly greater than peak aerial counts. Years with similar peak counts had different residence probabilities; hence, adjustments for turnover should be used in the future to assess annual population changes. Our results suggest that VA can support a significant portion of this red knot subspecies during migration in at least some years. Managing red knots for recovery should entail improving our understanding of the use of other Atlantic Coast sites and protecting key coastal habitat from disturbance and development. 相似文献
995.
A new species of the South American freshwater genus Euryrhynchus, E. tomasi sp. nov., is described on the basis of two specimens from French Guyana. The new species differs from all its congeners by the presence of two disto-lateral spines on the merus of the second pereiopod, combined with the absence of any carpal spines. The recent elevation of the euryrhynchids to family status is supported, whilst a discussion is presented of their systematic position and affinities, emphasising the remote systematic affinity with the Typhlocarididae, previously assumed to be closely related. An appraisal of the systematically important characters in the Euryrhynchidae highlights the need for a re-appraisal of the caridean superfamily Palaemonoidea. 相似文献
996.
Sylviornis neocaledoniae is represented in the sites of Kanumera, Isle of Pines, by a few cranial elements (palatines, quadrates, quadratojugal) but mainly by post-cranial remains. The fact that palatines are fused in the sagittal plane proves the palate of Sylviornis to be neognathous. The flightless bird's post-cranial skeleton is highly modified, but some anatomical characters show it can be assigned to Galliformes, and, amongst them, is closer to recent or extinct Megapodes than to any other family, Sylviornis neocaledoniae was probably exterminated by man who preserved its mythological memory under the name of Du. 相似文献
997.
In 1966, septal nuclei of unusual size in brains of kuru-diseased Fore people from the Eastern Highlands of New Guinea were reported (Beck and Gajdusek, 1966). Microscopic investigation which did not reveal any pathological changes in these nuclei led to the question of whether their large size could be a characteristic feature of the Fore (and perhaps also of other ethnic groups of New Guinea), rather than a consequence of the disease. We had at our disposal brains from patients of coastal areas of New Guinea who did not suffer from kuru. The septal areas of eight cases were investigated by serial sections and compared to those of nine European brains. No difference in size comparable to that reported in the earlier study could be detected. We conclude that a possible pecularity in the size of the septal nuclei of Fore people cannot be generalized to the entire population of New Guinea. 相似文献
998.
New Zealand's small freshwater fish fauna has been augmented by introductions of exotic species, primarily salmonids. Brown and rainbow trout have been successful and the chinook salmon has established anadromous populations. Although few explicit data are available, it appears that addition of large salmonids has had harmful impacts on some indigenous species, particularly several galaxiids; these appear to result from predation and competitive exclusion. Interactions may be chronic or catastrophic. It is difficult to determine causes of chronic interactions, many instances of which are likely to be occurring and escaping notice. Further, it is difficult to separate the effects of human-induced habitat deterioration from inter-specific interactions. Catastrophic interactions are much easier to observe but even here determining the nature of interactions and ascribing causes is fraught with difficulties. 相似文献
999.
Karyotypes of 82 individuals from five Platyrrhini species (Alouatta caraya, Aotus azarae, Callithrix jacchus, Cebus apella, andSaimiri sciureus) were studied and compared using a G-banding technique. Cytogenetic analysis showed full chromosome or full arm homologies
among these geographically neighbouring species. A small number of chromosomal rearrangements (inversions, deletions, and
translocations) could be detected among these taxa. These five species are closely related in chromosomal evolution. An interesting
correspondance was found betweenCebus apella chromosomes and those of the other four species.Alouatta caraya andCebus apella are the closest species.Callithrix jacchus andAotus azarae would have the most separated karyotypes. 相似文献
1000.
STEPHEN E. SPEYER CARLTON E. BRETT 《Lethaia: An International Journal of Palaeontology and Stratigraphy》1985,18(2):85-103
Clusters of well-preserved trilobites occur throughout lower and middle Paleozoic strata. This phenomenon, however, remains poorly understood. Several thin, regionally persistent beds in the Middle Devonian (Givetian) Hamilton Group of New York State display taphonomic and sedimentary features which indicate rapid burial by storm-generated clouds of fine-grained sediment. Furthermore, components in these units display little or no post-mortem disturbance and, therefore, reflect in faunal associations. These beds contain two types of clustered assemblages of the trilobites Phacops (Green), Greenops boothi (Green) and Dechenella rowi (Green). Body clusters comprise dense assemblages of three or more complete trilobite corpses. Moult clusters , in contrast, are composed of three more moult ensembles; i.e., articulated thoracopygidia in close proximity to corresponding cephala. Clusters are species-segregated and contain only a small portion of the total size range exhibited by trilobite species. Moreover, body clusters and moult clusters are morphometrically undifferentiated indicating that these two cluster modes represent related phenomena. Analogy with modern marine arthropods suggests that trilobites assembled into monospecific, age-segregated clusters and moulted prior to en masse copulation. 相似文献