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191.
The systematic treatment of Orobanche cumana Wallr. and O. cernua L. is controversial. Whereas some authors consider O. cumana as an infraspecific taxon of O. cernua , others treat it as a separate species. Furthermore, the nomenclature of the sunflower broomrape is unclear, and both names arc found without qualification in the literature. The objective of the present study has been to evaluate the distribution, morphology, and ecology of O. cernua and O. cumana in the Iberian Peninsula, as well as their seed oil fatty acid profile, which is a trait of great chemotaxonomic value. O. cernua was found parasitizing wild Compositac, mainly Artemisia spp., whereas O. cumana was exclusively found on cultivated sunflower. Both species clearly differ in morphological traits, especially plant height and build, length and structure of the inflorescence, corolla length and colour. Both species are characterized by contrasting seed oil fatty acid profiles, with high oleic acid concentration in O. cernua and high linoleic acid concentration in O. cumana. The evaluation of both taxa in the Iberian Peninsula gives additional support to those authors that treat them as separate species.  相似文献   
192.
SYNOPSIS. Coriphosphine staining of Stylonychia mytilus exconjugants at different times after separation reveals some details of the developing macronucleus. Green fluorescence is seen in both bands and heterochromatic blocks of the polytene chromosomes. No red fluorescence was observed along these chromosomes. Fragments of the old macronucleus and the pycnotic micronuclei have red or orange fluorescence. Red fluorescence is characteristic also of nucleoli in the new macronucleus.  相似文献   
193.
famsphere is a computer program that implements a distance‐based method to allocate families based on microsatellite marker information. It formalizes the exclusion method considering genotyping errors or mutations. Contrary to the standard exclusion method, famsphere provides a way to resolve conflicts in the case of multiple paternities. The information linked to the defined distances is similar to that of the transmission probabilities used in the likelihood approaches. However, in famsphere the information of loci is used as a whole, contrary to the likelihood approaches. famsphere is free software and can be downloaded from http://www.uvigo.es/webs/c03/webc03/XENETICA/XB2/antonio/famsphere/famsphere.htm  相似文献   
194.
Kånneby, T., Todaro, M. A., Jondelius, U. (2012). Phylogeny of Chaetonotidae and other Paucitubulatina (Gastrotricha: Chaetonotida) and the colonization of aquatic ecosystems. —Zoologica Scripta, 42, 88–105. Chaetonotidae is the largest family within Gastrotricha with almost 400 nominal species represented in both freshwater and marine habitats. The group is probably non‐monophyletic and suffers from a troubled taxonomy. Current classification is to a great extent based on shape and distribution of cuticular structures, characters that are highly variable. We present the most densely sampled molecular study so far where 17 of the 31 genera belonging to Chaetonotida are represented. Bayesian and maximum likelihood approaches based on 18S rDNA, 28S rDNA and COI mtDNA are used to reconstruct relationships within Chaetonotidae. The use of cuticular structures for supra‐specific classification within the group is evaluated and the question of dispersal between marine and freshwater habitats is addressed. Moreover, the subgeneric classification of Chaetonotus is tested in a phylogenetic context. Our results show high support for a clade containing Dasydytidae nested within Chaetonotidae. Within this clade, only three genera are monophyletic following current classification. Genera containing both marine and freshwater species never form monophyletic clades and group with other species according to habitat. Marine members of Aspidiophorus appear to be the sister group of all other Chaetonotidae and Dasydytidae, indicating a marine origin of the clade. Halichaetonotus and marine Heterolepidoderma form a monophyletic group in a sister group relationship to freshwater species, pointing towards a secondary invasion of marine environments of these taxa. Our study highlights the problems of current classification based on cuticular structures, characters that show homoplasy for deeper relationships.  相似文献   
195.
Morphogenesis in ammonites - differences linked to growth pattern   总被引:1,自引:0,他引:1  
This paper analyzes the relationship existing between septa and ornamentation in ammonites showing two basic growth patterns: cyclic and uniform. In both CMCS there exists a strong correlation between ornamentation size and interseptal distance, both characters, being related to each other through growth rate. Nevertheless, in the case of cyclic growth, regulation mechanisms appear which prevent the formation of non-adaptative structures induced by extreme deviations in growth rate.  相似文献   
196.
Giemsa C-banding is utilized for the first time to characterize eight taxa of the genus Serapias . Heterochromatin distribution indicated that the Serapias species form a very homogeneous group. All the species possess chromosome pairs with similar heterochromatin patterns. C-banding showed conspicuous bands located around the centromeres, with some het-erochromatic short arms. There was more heterochromatin in S. apulica and S. nurrika than in the other taxa. Extensive centromeric heterochromatin may indicate recent structural rearrangements in the chromosome complement. Taken altogether, karyomorphology indicates a rather recent origin for the genus Serapias , which might also account for the small amount of interspecific variation observed.  相似文献   
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1. Natura 2000 network (N2000) and national protected areas (NPAs) are recognised as the most important core ‘units’ for biological conservation in Europe. 2. Species distribution models (SDMs) were developed to detect the potential distribution of the rare and threatened cerambycid beetle Rosalia alpina L. in Europe, and the amount of suitable habitat within the N2000 network [special areas of conservation (SACs) and special protection areas (SPAs)], NPAs (e.g. national parks, regional parks, state reserves, natural monuments and protected landscapes) and the overall European protected area network (EPAN) (N2000 + NPAs) was quantified. 3. According to this analysis, the suitable habitat for R. alpina in Europe amounts to c. 754 171 km2 and stretches across substantially uninterrupted areas from Portugal to Romania (west to east) and from Greece to Germany (south to north). The overlay between the existing system of conservation areas in Europe (N2000 and NPAs) and the binary map for R. alpina showed that only c. 42% of potential habitat is protected. SACs and SPAs protect c. 25% and 21% of potential habitat, respectively. However, because the two site types often spatially overlap, when taken together the entire N2000 network protects c. 31% of potential habitat. Instead, NPAs offer a degree of protection of c. 29%. Overall, almost 60% of the area potentially suitable for the species is unprotected by the EPAN, an aspect that should be considered carefully when planning the conservation of this beetle at a large scale. 4. These results may also help to focus field surveys in selected areas where greater chances of success are encountered to save resources and increase survey effectiveness.  相似文献   
200.
Five species of sea skaters, genus Halobates Eschscholtz, are the only insects to have successfully colonized the open ocean. In addition, 38 species are found in sheltered coastal waters throughout tropical Indo-Pacific. The taxonomy of the genus is relatively well known, and the phylogeneuc relationships between extant species have recently been analysed (using cladistic methods). In the present paper, we describe the first fossil species of sea skaters, Halobates ruffoi sp. no v. from the Eocene deposit 'Pesciara di Bolca', in the province of Verona, northeastern Italy (geological age about 45 Myr). The significance of this fossil in setting the time scale for the reconstructed phylogeny and anagenesis of adaptive features of sea skaters, and in understanding the evolution and historical zoogeography of these marine insects is discussed.  相似文献   
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