Search results for "Systematics"
showing 10 items of 6702 documents
The role of hybridization in the evolution ofCousinias.str.(Asteraceae, Cardueae)
2009
Abstract Mehregan I. & Kadereit J. W.: The role of hybridization in the evolution of Cousinia s.str. (Asteraceae, Cardueae). — Willdenowia 39: 35–47. — Online ISSN 1868-6397; © 2009 BGBM Berlin-Dahlem. doi:10.3372/wi.39.39102 (available via http://dx.doi.org/) In order to assess the possible role of interspecific hybridization for the evolution of the high diversity of Cousinia subg. Cousinia (Cousinia s.str., c. 600 species), we examined the frequency of hybridization in this taxon. For this, hypothetical hybrid combinations published in the literature (28 putative hybrids and 11 intermediate forms) were critically examined. In addition, two hybrids were identified in the present study by …
Evolution, ecology and systematics of Soldanella (Primulaceae) in the southern Apennines (Italy)
2015
Background The populations of Soldanella (Primulaceae) of the southern Apennines (Italy) are unique within the genus for their distribution and ecology. Their highly fragmented distribution range, with three main metapopulations on some of the highest mountains (Gelbison, Sila and Aspromonte massifs) of the area, poses intriguing questions about their evolutionary history and biogeography, and about the possibility of local endemisms. Aims and methods In order to clarify the phylogeny and biogeography of the three metapopulations of Soldanella in the southern Apennines, attributed to S. calabrella to date, and to identify possible local endemisms, a comparative approach based on the study o…
The diaptomid fauna of Israel (Copepoda, Calanoida, Diaptomidae), with notes on the systematics of Arctodiaptomus similis (Baird, 1859) and Arctodiap…
2014
Background: To date, only scarce information is available about the diaptomid copepods of the Middle East despite the ecological and biogeographical importance of the family Diaptomidae in the inland waters of the Holarctic region. Moreover, the taxonomic status of some of the taxa occurring in the area is in need of revision. We studied crustaceans collected from temporary and permanent lentic water bodies in Israel with the aim of providing an updated census of the diaptomid copepods occurring in the country. Furthermore, we morphologically and genetically analysed samples of Arctodiaptomus similis s.l. to shed light on its taxonomy. Results: Five diaptomid taxa were collected during this…
Systematics and Phylogeny
2013
Remarks on biology, vocalisations and systematics of Urocynchramus pylzowi Przewalski (Aves, Passeriformes)
2006
Several field studies in the Qinghai Nanshan area (Qinghai Province, China) have added new findings to the scant knowledge about Przewalski´s Rosefinch Urocynchramus pylzowi Przewalski, 1876. The hitherto completely unknown vocalisations are described and used to clarify systematic relationships. Although one could argue for a relationship to Uragus sibiricus (Pallas), based on nearly identical auditory impression and sonagram structures of their songs, detailed measurements show significant differences in time and frequency parameters. Moreover a mtDNA analysis shows no close phylogenetic relationship to either of three major emberizid clades. These results support the hypothesis that Uroc…
Systematics of European coastal anchovies (genus Engraulis Cuvier).
2021
Reports of morphological differences between European anchovy (Engraulis cf. encrasicolus) from coastal and marine habitats have long existed in the ichthyologic literature, and have given rise to a long-standing debate on their taxonomic status. More recently, molecular studies have confirmed the existence of genetic differentiation between the two anchovy ecotypes. Using ancestry-informative markers, we show that coastal anchovies throughout the Mediterranean share a common ancestry, and that substantial genetic differentiation persists in different pairs of coastal/marine populations despite the presence of limited gene flow. On the basis of genetic and ecological arguments, we propose t…
Reviewing lymnaeid vectors of fascioliasis by ribosomal DNA sequence analyses.
2005
AbstractSnails of the family Lymnaeidae are of great parasitological importance due to the numerous helminth species they transmit, mainly trematodiases (such as fascioliasis) of considerable medical and veterinary impact. The present knowledge of the genetics and host–parasite relationships of this gastropod group is far from adequate. Fascioliasis is caused by two species, Fasciola hepatica and F. gigantica, which, as in the case of other trematodes, show a marked snail host specificity. Many lymnaeid species involved in fascioliasis transmission still show a confused systematic-taxonomic status. The need for tools to distinguish and characterize species and populations of lymnaeids is ev…
Allozymic variation and divergence in three species of Antirrhinum L. (Scrophulariaceae-Antirrhineae)
1999
Abstract An allozymic study of three wild species of Antirrhinum L.—A. lopesianum RothmA. mollissimum Rothm. and A. microphyllum Rothm.—is described. All are members of subsectionKickxiella Rothmand are narrow-range endemics of the Iberian Peninsula. The variability of the different loci, as well as the number and mobility of the alleles, differ among the three species, a demonstration of the usefulness of allozymes for the systematics of the genus. The finding of alleles unique to each species indicates high divergence among species suggesting ancient diversification, and supports the hypothesis of a geographical model of speciation. All three species show high levels of within-species var…
Beiträge zur Kenntnis der Gattung Pseudoscabiosa (Dipsacaceae)
1997
Die Gattung Pseudoscabiosa DEVESA wird untersucht unter besonderer Berucksichtigung der Bedeutung der Mikromorphologie der Behaarung fur die Systematik dieser Gattung. Eine neue nordafrikanische Art, Pseudoscabiosa africana (FONT QUER) ROMO, CIRUJANO, PERIS & STUBING comb. & stat. nov., wird aufgestellt. The genus Pseudoscabiosa DEVESA is reviewed, stressing the importance of the micromorphology of the hair-covering for the systematics of this genus. A new Northafrican species is proposed, Pseudoscabiosa africana (FONT QUER) ROMO, CIRUJANO, PERIS & STUBING comb. & stat. nov.
Systematics, Phylogeny, and Evolution of Papaver californicum and Stylomecon heterophylla (Papaveraceae)
2011
Abstract We present a detailed comparison of Papaver californicum and Stylomecon heterophylla, which earlier were found to be sister species and most closely related to Meconopsis cambrica + Papaver s.str. from western Eurasia. The two species of winter annuals differ mainly in the shape of their distal cauline leaves, coloration of petals and staminal filaments, and most notably morphology of the gynoecium and capsule, with Papaver californicum having a sessile stigmatic disc and Stylomecon heterophylla having a distinct style. They were earlier found to differ in ploidy, with chromosome numbers of 2n = 28 (Papaver californicum) and 2n = 56 (Stylomecon heterophylla). Mapped distributio…