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Morphometric analysis of interspecific and microgeographic variation of crayfish from a Mexican cave
GIULIANA ALLEGRUCCI FABIOLA BALDARI DONATELLA CESARONI ROGER S. THORPE† VALERIO SBORDONI 《Biological journal of the Linnean Society. Linnean Society of London》1992,47(4):455-468
Two undescribed species of Procambarus crayfish (Crustacea, Decapoda) inhabit the subterranean stream running in the recently explored Cueva de Los Camarones, Chiapas, Mexico. Individuals ranging from dark, robust, large-eyed forms with an epigean mien to pale, comparatively slender, microphthalmic ones resembling related troglobites were found, but only the extremes could be distinguished visually. Evolutionary relationships among individuals were investigated morphometrically by means of multivariate analysis'on 14 body dimensions. These analyses revealed a significant discontinuity between the two species, mainly determined by the shape of the rostrum, chelae and telson. The occurrence of a few aberrant phenotypes may indicate the existence of some gene flow between the two species.
Microgeographic variation was demonstrated within the less cavernicolous species. The characters involved were the same as those that discriminate between the two species. These results are compared with allozymic data presented in a parallel paper and the role of genie introgression and environmental induction are discussed. 相似文献
Microgeographic variation was demonstrated within the less cavernicolous species. The characters involved were the same as those that discriminate between the two species. These results are compared with allozymic data presented in a parallel paper and the role of genie introgression and environmental induction are discussed. 相似文献
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JOSEP PE
UELAS PATRICIA PRIETO CLAUS BEIER CARLA CESARACCIO PAOLO
De ANGELIS GIOVANBATTISTA
De DATO BRIDGET A. EMMETT MARC ESTIARTE JNOS GARADNAI ANTONIE GORISSEN EDIT KOVCS LNG GY
RGY KR
EL‐DULAY LAURA LLORENS GRAZIA PELLIZZARO TORBEN RIIS‐NIELSEN INGER K. SCHMIDT COSTANTINO SIRCA ALWYN SOWERBY DONATELLA SPANO ALBERT TIETEMA 《Global Change Biology》2007,13(12):2563-2581
We used a nonintrusive field experiment carried out at six sites – Wales (UK), Denmark (DK), the Netherlands (NL), Hungary (HU), Sardinia (Italy – IT), and Catalonia (Spain – SP) – along a climatic and latitudinal gradient to examine the response of plant species richness and primary productivity to warming and drought in shrubland ecosystems. The warming treatment raised the plot daily temperature by ca. 1 °C, while the drought treatment led to a reduction in soil moisture at the peak of the growing season that ranged from 26% at the SP site to 82% in the NL site. During the 7 years the experiment lasted (1999–2005), we used the pin‐point method to measure the species composition of plant communities and plant biomass, litterfall, and shoot growth of the dominant plant species at each site. A significantly lower increase in the number of species pin‐pointed per transect was found in the drought plots at the SP site, where the plant community was still in a process of recovering from a forest fire in 1994. No changes in species richness were found at the other sites, which were at a more mature and stable state of succession and, thus less liable to recruitment of new species. The relationship between annual biomass accumulation and temperature of the growing season was positive at the coldest site and negative at the warmest site. The warming treatment tended to increase the aboveground net primary productivity (ANPP) at the northern sites. The relationship between annual biomass accumulation and soil moisture during the growing season was not significant at the wettest sites, but was positive at the driest sites. The drought treatment tended to reduce the ANPP in the NL, HU, IT, and SP sites. The responses to warming were very strongly related to the Gaussen aridity index (stronger responses the lower the aridity), whereas the responses to drought were not. Changes in the annual aboveground biomass accumulation, litterfall, and, thus, the ANPP, mirrored the interannual variation in climate conditions: the most outstanding change was a decrease in biomass accumulation and an increase in litterfall at most sites during the abnormally hot year of 2003. Species richness also tended to decrease in 2003 at all sites except the cold and wet UK site. Species‐specific responses to warming were found in shoot growth: at the SP site, Globularia alypum was not affected, while the other dominant species, Erica multiflora, grew 30% more; at the UK site, Calluna vulgaris tended to grow more in the warming plots, while Empetrum nigrum tended to grow less. Drought treatment decreased plant growth in several studied species, although there were some species such as Pinus halepensis at the SP site or C. vulgaris at the UK site that were not affected. The magnitude of responses to warming and drought thus depended greatly on the differences between sites, years, and species and these multiple plant responses may be expected to have consequences at ecosystem and community level. Decreases in biodiversity and the increase in E. multiflora growth at the SP site as a response to warming challenge the assumption that sensitivity to warming may be less well developed at more southerly latitudes; likewise, the fact that one of the studied shrublands presented negative ANPP as a response to the 2003 heat wave also challenges the hypothesis that future climate warming will lead to an enhancement of plant growth and carbon sequestration in temperate ecosystems. Extreme events may thus change the general trend of increased productivity in response to warming in the colder sites. 相似文献
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WALLACE ARTHUR DONATELLA FODDAI CHRIS KETTLE JOHN G. E. LEWIS MIROSLAW LUCZYNSKI ALESSANDRO MINELLI 《Biological journal of the Linnean Society. Linnean Society of London》2001,74(4):489-499
Geophilomorph centipedes provide an unusual opportunity to examine patterns of variation in segment number within extant species. (Most other arthropod species are invariant in this respect.) Recent work on several geophilomorph species has revealed latitudinal clines in segment number, but has generally not called into question the identities of the species themselves. However, analysis of a unique pattern of variation in British populations of Geophilus carpophagus Leach, coupled with other morphological and enzyme data, reveals a cryptic species, Geophilus easoni sp. nov. This species has not yet been detected on the European mainland. Four distinct hypotheses are advanced regarding the speciation event through which G. easoni arose and the phylogeographic processes that resulted in the present distributions of the two species in Britain. Further study will be necessary to test these hypotheses. In any event, G. carpophagus and G. easoni provide something that has until now been absent: a case study of the genetic differences between closely-related geophilomorph species. 相似文献
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CIAMPOLINI FABRIZIO; FALERI CLAUDIA; DI PIETRO DONATELLA; CRESTI MAURO 《Annals of botany》1996,78(6):759-764
Studies were carried out on structural and cytochemical aspectsof the stigma and style ofVitis vinifera . The stigma is ofthe wet papillate type with a continuous cuticle and pellicle.During the development of the papillae, the cell walls increasein thickness and produce a secretion product constituted oflipids that pass through the wall forming the exudate. The styleis solid with a central core of transmitting tissue which hasconspicuous intercellular spaces that increase remarkably fromthe periphery to the centre where the cuticle is present. Theintercellular spaces, where the pollen tubes grow, contain amatrix that includes polysaccharides, pectic substances andscattered areas of lipidic nature. Cytochemistry; stigma; style; ultrastructure; Vitis vinifera 相似文献
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