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1.
Abstract Eight families of Symphyta for the Western Hemisphere south of the United States are reviewed: Xyelidae (one genus, two species), Pamphiliidae (one genus, four species), Cimbicidae (five genera, nine species), Diprionidae (three genera, thirteen species), Xiphydriidae (four genera, seventeen species), Siricidae (six genera, nine species), Orussidae (five genera, twelve species), and Cephidae (one genus, one species). New taxa are Acantholyda nigrostigmata (Pamphiliidae); Zadiprionfalsus, Neodiprion bicolor, N.equalis, N.omosus (Diprionidae); Derecyrta circularis, Steirocephala lateralba (Xiphydriidae); Sirotremex, S.flammeus (Siricidae); and Ophrynopus depressatus, O.plaumanni (Orussidae). Lopesiana is a new name for Lopesia Conde (Cimbicidae). Three new combinations and six new synonyms are proposed. The Xyelidae, Pamphiliidae, Diprionidae, Siricidae and Cephidae are primarily northern groups with southern extensions into Mexico, Central America and/or Cuba. The Cimbicidae, Xiphydriidae and Orussidae are more generally distributed throughout the neotropics. Keys to families, genera and species are provided.  相似文献   

2.
Rarity, commonness, and patterns of species richness: the mammals of Mexico   总被引:2,自引:0,他引:2  
Aim To determine whether rare or common species contribute most to overall patterns of spatial variation in extant species richness. Location Mexico. Methods Using data on the distribution of mammal species across Mexico at a quarter degree resolution, we ranked species from the most widespread to the most restricted (common‐to‐rare) within the study area, and from the most restricted to the most widespread (rare‐to‐common), and generated a sequence of patterns of species richness for increasing numbers of species. At each stage along both series of richness patterns, we correlated the species richness pattern for the subassemblage with that of the full assemblage. This allows comparison of subassemblages of the n most common with the n most rare species, in terms of how well they match the full assemblage richness pattern. Further analyses examined the effects on these patterns of correlation of the amount of raw information contained in the distributions of given numbers of rare and common species. Results For the mammals of Mexico the more widely distributed species contribute disproportionately to patterns of species richness compared with more restricted species, particularly for non‐volant species and endemic species. This is not simply a consequence of differences in the volumes of information contained in the distributions of rare and common species, with the disproportionate contribution of common species if anything being sharpened when these differences are taken into account. The pattern is most clearly demonstrated by endemic species, suggesting that the contribution of common species is clearest when the causes of rarity and commonness are limited to those genuinely resulting in narrow and widespread geographical ranges, respectively, rather than artificial (e.g. geopolitical) boundaries to the extents of study regions. Conclusions Perhaps surprisingly, an understanding of the determinants of overall patterns of species richness may gain most from consideration of why common species occur in some areas and are absent from others, rather than consideration of the distributions of rare species.  相似文献   

3.

The cosmopolitan subfamilies Aphrodinae, Jassinae, Xestocephalinae, Idiocerinae, and Macropsinae are diagnosed and the New Zealand species described and illustrated. Each subfamily is represented in New Zealand by only one or two species, those in Idiocerinae having been introduced from Europe or North America. The species Euacanthella brunnea Evans (Aphrodinae) is synonymised with the Australian species E. insularis Evans (new synonymy).  相似文献   

4.
This study examines species-specific distributions of preimaginal black flies (Diptera: Simuliidae) over two large spatial scales (within and across ecoregions) and two seasons (spring and summer). The study area in the western two-thirds of South Carolina, United States, was divided into three ecoregions (Mountains, Piedmont, Sandhills). The mean correct classification of species distributions among stream sites was 81.3%. Predictability of species distributions varied with spatial scale, location, and time. Species occurrence was not independent of ecoregion; distributions of 12 of the 13 species examined at this scale were predictable on the basis of changes in water column (temperature, percentage dissolved oxygen) and channel characters (velocity, streambed-particle size). However, with the exception of the Mountains during the summer, predicting species distributions within ecoregions was far less successful than predicting distributions across these regions; predictability was particularly poor in the Sandhills. Seasonal effects on predictability were most pronounced in the Mountains. As stream sites became more homogeneous, predictive capability declined. Species-level identifications, aided by cytogenetic techniques, were of paramount importance in recognizing the association between species distributions and stream conditions, emphasizing that considerable ecological information is lost when species are not considered. This study emphasizes the critical role of taxonomic resolution, linked with spatial and temporal scale of observation, in elucidating patterns of species assemblages. It also demonstrates that predictability of species distributions at a fixed scale can vary with geographic location and time. Received: 2 May 1997 / Accepted: 22 September 1997  相似文献   

5.
To investigate the evolutionary relationships among species of Afrotrichloris, Apochiton, Coelachyrum, Dinebra, Eleusine, Leptochloa, and Schoenefeldia of subtribe Eleusininae, a phylogeny based on DNA sequences from nine gene regions (ITS, rps16-trnK, rps3, rps16, rpoC2, rpl32-trnL, ndhF, ndhA, ccsA) is presented. Previous molecular phylogenies indicated that Coelachyrum was polyphyletic and Schoenefeldia was paraphyletic, with Afrotrichloris embedded within it. Apochiton burttii was embedded in the Coelachyrum clade paired with C. longiglume, Coelachyrumpoiflorum was placed outside of Coelachyrum and sister to Eleusine, and Schoenefeldia is paraphyletic, with its two species forming a grade sister to Afrotrichoris. Our molecular phylogeny supports recognition of a new genus, Schoenefeldiella, and a new combination, Schoenfeldiella transiens. In addition, we provide generic emendations for Coelachyrum, which now includes five species including a new combination proposed here, Coelachyrum burttii, and Eleusine, which now includes 11 species.  相似文献   

6.
本文记述西双版纳6种淡水蟹类的种类组成及分布,其中包括二新种的描述。  相似文献   

7.
Termites are an abundant and diverse group in the Neotropics with about 500 species representing 83 genera. The paucity of the termite fauna recorded from Ecuador is due, in part, to a lack of deliberate surveys. We revise the termite fauna of Ecuador and raise the number of species from 25 species to 72 based on our recent termite surveys. Of the 72 species, 18 could not be conclusively identified and are likely new species. Given the limited area that has been covered in surveys of the Ecuadorian termite fauna, there are undoubtedly many more species to be recorded for Ecuador, primarily in the eastern lowland areas, cloud forests on both the eastern and western slopes of the Andes, and the Amazonian lowland forests.  相似文献   

8.
We report 20 new species records for the Coleoptera fauna in New Brunswick, Canada, five of which are new records for the Maritime provinces, including one species that is new for Canada. One species of Kateretidae, Kateretes pusillus (Thunberg) is newly recorded for New Brunswick and the Maritime provinces. Stelidota octomaculata (Say), Phenolia grossa (Fabricius), andCryptarcha strigatula Parsons of the family Nitidulidae are added to the faunal list of New Brunswick; the latter species is new to the Maritime provinces. Two species of Cerylonidae, Philothermus glabriculus LeConte and Cerylon unicolor (Ziegler), are reported for the first time for New Brunswick. Philothermus glabriculus is new for the Maritime provinces. Two species of Endomychidae, Hadromychus chandleri Bousquet and Leschen and Danae testacea (Ziegler) are newly recorded for New Brunswick. Three species of Coccinelidae, Stethorus punctum punctum (LeConte), Naemia seriata seriata Melsheimer, and Macronaemia episcopalis (Kirby) are added to the provincial list. Macronaemia episcopalis (Kirby) is a species new to the Maritime provinces. Nine species of Latridiidae, Cartodere nodifer (Westwood), Dienerella ruficollis (Marsham), Enicmus aterrimus Motschulsky, Enicmus fictus Fall, Encimus histrio Jay and Tomlin, Lathridius minutus (Linnaeus), Stephostethus productus Rosenhauer, Corticaria elongata (Gyllenhal), and Corticarina longipennis (LeConte) are newly recorded for New Brunswick. Stephostehus productus is newly recorded from Canada. Collection and habitat data are presented for all these species.  相似文献   

9.
Most megadiversity regions lack basic wild animal diversity information such as species lists. This absence of basic knowledge restricts the development and effectiveness of conservation action plans, which are urgently needed for animal groups such as amphibians, the most threatened vertebrate group in the world. In this study, we estimated Brazilian anuran diversity based on species range distribution shapes and evaluated factors that likely affect species lists, such as current taxonomy knowledge, current number of specimens collected in each region, biome characteristics, and anuran size (snout–vent length). We were able to demonstrate differences among the distributional patterns of species within each biome and each Brazilian federative state and among certain factors that influence their diversity, such as latitudinal variation. In this integrative study, we provide zoogeographic information about the richest (in terms of anuran biodiversity) country in the world (at least 849 described species, about 60% of which are endemic), which may be fundamental to future conservation actions in Brazil.  相似文献   

10.
Abstract

The checklist comprises all species of six families of Iranian aquatic Polyphaga (Coleoptera). In total, 43 species/subspecies within the families, Georissidae (one species), Helophoridae (25 species and two subspecies), Hydrochidae (three species), Spercheidae (one species), Curculionidae (nine species) and Erirhinidae (two species) are listed for the fauna of Iran. Helophorus (Rhopalohelophorus) nanus Sturm, 1836 Sturm, J. (1836), Deulschlands Fauna in Abbildungen nach der Natur mit Beschreibungen. V. Abtheilung. Die Inseclen. Zehntes Bändchen. Käfer, Nürnberg: J. Sturm, 108 pp., pl. 216–227. (also under title: Deutschlands Insecten, Käfer). [Google Scholar] (Helophoridae) is recorded for the first time from Iran. We also present two additional species lists: one with incorrect records (one species) and the other with unidentified species.  相似文献   

11.
Several extrinsic factors (area, native species diversity, human population size and latitude) significantly influence the non-native species richness of plants, over several orders of magnitude. Using several data sets, I examine the role of these factors in non-native species richness of several animal groups: birds, mammals and herptiles (amphibians, reptiles). I also examine if non-native species richness is correlated among these groups. I find, in agreement with Sax [2001, Journal of Biogeography 28: 139–150], that latitude is inversely correlated with non-native species richness of many groups. Once latitude is accounted for, area, human population size and native plant species richness are shown to be important extrinsic factors influencing non-native animal species. Of these extrinsic factors, human population size and native plant species richness are the best predictors of non-native animal species richness. Area, human population size and native plant species richness are highly intercorrelated, along with non-native species richness of all taxa. Indeed a factor analysis shows that a single multivariate axis explains over half of the variation for all variables among the groups. One reason for this covariation is that humans tend to most densely occupy the most productive and diverse habitats where native plant species richness is very high. It is thus difficult to disentangle the effects of human population size and native species richness on non-native species richness. However, it seems likely that these two factors may combine to increase non-native species richness in a synergistic way: high native species richness reflects greater habitat variety available for non-native species, and dense human populations (that preferentially occupy areas rich in native species) increase non-native species importation and disturbance of local habitats.  相似文献   

12.
宋础良 《生物多样性》2020,28(11):1345-57
群落内物种间相互作用的结构是高度组织化的。群落结构对多物种共存的影响机制是群落生态学的核心科学问题之一。目前生态学界在这一问题上存在多种不同的观点。一个可能的原因是, 由于环境因子的复杂性, 大部分研究忽略了环境因子对群落结构和物种共存的重要影响。在这一背景下, 近期发展起来的结构稳定性理论系统地联系了群落结构、环境因子和物种共存, 并在此基础上建立了一个和经验数据紧密结合的理论框架。本文首先简要回顾了当前关于群落结构研究的争鸣, 然后介绍了结构稳定性的理论框架和计算方法, 最后详细介绍了结构稳定性理论在不同生态群落和不同生态学问题中的应用。在全球气候变化的背景下, 结构稳定性理论提供了一种新的视角来理解群落层面的生物多样性维持机制。  相似文献   

13.
The bird fauna of the Brazilian Atlantic Forest is exceptionally diverse and threatened, with high levels of endemism. Available lists of the endemic birds of the Atlantic Forest were generated before recent taxonomic revisions lumped or split species and before the recent increase in species occurrence records. Our objective, therefore, was to compile a new list of the endemic birds of the Atlantic Forest, characterize these species in terms of conservation status and natural history traits, and map remaining vegetation and protected areas. We combined GIS analysis with a literature search to compile a list of endemic species and, based on the phylogeny and distribution of these species, characterized areas in terms of species richness, phylogenetic diversity, and endemism. We identified 223 species of birds endemic to the Atlantic Forest, including 12 species not included in previous lists. In addition, 14 species included in previous lists were not considered endemic, either because they occur outside the Atlantic Forest biome or because they are not considered valid species. The typical Atlantic Forest endemic bird is a small forest‐dependent invertivore. Of the species on our list, 31% are considered threatened or extinct. Only ~ 34% of the spatial analysis units had > 10% forest cover, and protected area coverage was consistently low (< 1%). In addition, we found spatial incongruity among the different measures of biodiversity (species richness, relative phylogenetic diversity, restricted‐range species, and irreplaceability). Each of these measures provides information concerning different aspects of biological diversity. However, regardless of which aspect(s) of biodiversity might be considered most important, preservation of the remaining areas of remnant vegetation and further expansion of protected areas are essential if we are to conserve the many endemic species of birds in the Atlantic Forest.  相似文献   

14.
Turbellaria Lecithoepitheliata: morphology,systematics, phylogeny   总被引:7,自引:7,他引:0  
A review of the literature on the world fauna of lecithoepitheliata and Prolecithophora and extensive observations by the author on species of the Prorhynchidae, including cosmopolitan species as well as some endemic to Lake Baikal, and on endemic species of Baicalarctiinae (Prolecithophora) show that the Prorhynchidae and Gnosonesimidae are properly classified in the Neoophora. The morphological similarity of the Prorhynchidae and Prolecithophora proves these taxa are closely related. A hypothesis relating the Lecithoepitheliata Prorhynchidae to primitive prolecithophorans appears to be the only tenable hypothesis on the phylogeny of Lecithoepitheliata. The question of whether the Lecithoepitheliata is monophyletic still needs investigation; more evidence on the phylogeny of the Gnosonesimidae is needed.  相似文献   

15.
Tetrahymena mitochondrial cox1 barcodes and nuclear SSUrRNA sequences are particularly effective at distinguishing among its many cryptic species. In a project to learn more about Tetrahymena natural history, the majority of >1,000 Tetrahymena‐like fresh water isolates were assigned to established Tetrahymena species with the remaining assigned to 37 new species of Tetrahymena, nine new species of Dexiostoma and 12 new species of Glaucoma. Phylogenetically, all but three Tetrahymena species belong to the well‐established “australis” or “borealis” clades; the minority forms a divergent “paravorax” clade. Most Tetrahymena species are micronucleate, but others are exclusively amicronucleate. The self‐splicing intron of the LSUrRNA precursor is absent in Dexiostoma and Glaucoma and was likely acquired subsequent to the “australis/borealis” split; in some instances, its sequence is diagnostic of species. Tetrahymena americanis, T. elliotti, T. gruchyi n. sp., and T. borealis, together accounted for >50% of isolates, consistent with previous findings for established species. The biogeographic range of species found previously in Austria, China, and Pakistan was extended to the Nearctic; some species show evidence of population structure consistent with endemism. Most species were most frequently collected from ponds or lakes, while others, particularly Dexiostoma species, were collected most often from streams or rivers. The results suggest that perhaps hundreds of species remain to be discovered, particularly if collecting is global and includes hosts of parasitic forms.  相似文献   

16.
This study explores the association of 24 polychaete species with sandy and muddy habitats located in a sub-arctic fjord, and across Atlantic Canada including Labrador, Newfoundland, and the Gulf of St. Lawrence. Key characters used to facilitate species identification are also summarized. Within Bonne Bay, distinctive polychaete assemblages were associated with specific sediment types and polychaete species richness and density were significant both predictors of corresponding total (infaunal) density and species richness. Polychaetes were denser and more diverse in sandy sediments, partly because sandy locales were associated with the outer portion of the bay, and therefore were closer to the more productive and diverse Gulf of St. Lawrence. In general, species that occupied both sediment types were more widely distributed within Bonne Bay and across the region. The biogeography of most species also suggests that the Bonne Bay fauna is transitional between Labrador and Acadian biogeographic provinces.  相似文献   

17.
18.
Species: the concept, category and taxon   总被引:2,自引:0,他引:2  
The term species by itself is vague because it refers to the species concept, the species category and the species taxon, all of which are distinct although related to one another. The species concept is not primarily a part of systematics, but has always been an integral part of basic biological theory, It is based on evolutionary theory and applies only to sexually reproducing organisms. The species concept and the phyletic lineage concept are quite distinct although they are related to one another. The important aspect of the species concept is lack of gene flow between different species, and hence the defining criterion of the species is genetic isolation. The species concept is often considered as non‐dimensional, both in time and space. Species possess three different major properties, namely genetic isolation, reproductive isolation and ecological isolation; these properties evolve at different times and under the effect of different causes during the speciation process. Speciation requires an external isolating barrier during the initial allopatric phase in which genetic isolation evolves and must reach 100% efficiency. The subsequent sympatric phase of speciation occurs after the disappearance of the external isolating barrier when members of the two newly evolved species can interact with one another and exert mutual selective demands on one another. Much of the reproductive and ecological isolation evolves during this secondary sympatric phase. The species category is a rank in the taxonomic hierarchy and serves as the basis on which the diversity of organisms is described; it is not the same as the species concept. The species category applied to all organisms, sexually and asexually reproducing. The species taxon is the practical application of the species category in systematics with the recognition of species taxa requiring many arbitrary decisions. No single set of rules exist by which the species category can be applied to all organisms. Recognition of species taxa in asexually reproducing organisms is based on amount of variation and gaps in the variation of phenotypic features associated with ecological attributes of these organisms as compared with similar attributes in sympatric species taxa of sexually reproducing organisms. Species taxa are multidimensional in that they exist over space–time and often have fuzzy borders. Because recognition of species taxa, including those in sexually reproducing organisms, depends on many arbitrary decisions especially when dealing with broad geographical and temporal ranges, species taxa cannot be used as the foundation for developing and testing theoretical concepts in evolutionary theory which can only be done with the non‐dimensional species concept.  相似文献   

19.
Biodiversity has been declining in many areas, and there is great interest in determining whether this decline affects ecosystem functioning. Most biodiversity—ecosystem functioning studies have focused on the effects of species richness on net primary productivity. However, biodiversity encompasses both species richness and evenness, ecosystem functioning includes other important processes such as decomposition, and the effects of richness on ecosystem functioning may change at different levels of evenness. Here, we present two experiments on the effects of litter species evenness and richness on litter decomposition. In the first experiment, we varied the species evenness (three levels), identity of the dominant species (three species), and micro-topographic position (low points [gilgais] or high points between gilgais) of litter in three-species mixtures in a prairie in Texas, USA. In a second experiment, we varied the species evenness (three levels), richness (one, two, or four species per bag), and composition (random draws) of litter in a prairie in Iowa, USA. Greater species evenness significantly increased decomposition, but this effect was dependent on the environmental context. Higher evenness increased decomposition rates only under conditions of higher water availability (in gilgais in the first experiment) or during the earliest stages of decomposition (second experiment). Species richness had no significant effect on decomposition, nor did it interact with evenness. Micro-topographic position and species identity and composition had larger effects on decomposition than species evenness. These results suggest that the effects of litter species diversity on decomposition are more likely to be manifested through the evenness component of diversity than the richness component, and that diversity effects are likely to be environmentally context dependent.  相似文献   

20.
Two species of Sphindidae, Odontosphindus denticollis LeConteand Sphindus trinifer Casey, are reported for the first time for New Brunswick. Another species, Sphindus near americanus LeConte is reported from the province but may be an undescribed species, pending further study. Five species of Erotylidae are newly recorded for the province, including Tritoma humeralis Fabricius and Tritoma sanguinipennis (Say), which are new to the Maritime provinces. Three species of Monotomidae are added to the New Brunswick faunal list, including Pycnotomina cavicollis (Horn), which is newly recorded for the Maritime provinces. Six additional species of Cryptophagidae are reported for the province and the presence of Antherophagus convexulus LeContein New Brunswick is confirmed. Cryptophagus pilosus Gyllenhal and Myrmedophila americana (LeConte) are newly reported to the Maritime provinces.  相似文献   

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