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Relevant Characters (relevant + character)

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Life Sciences100%

Selected Abstracts

Taxonomy and biogeography of Central European Kybos (Insecta, Hemiptera, Cicadellidae)

MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 1 2009
Roland Mühlethaler
Abstract The Central European species of the taxonomically difficult Holarctic typhlocybine genus Kybos are revised. Currently it is impossible to identify females and nymphs. In addition the otherwise diagnostic shape of the male genitalia is linked by intermediates in some morphologically similar nominal species. The second important diagnostic structure, the male sound apodemes, is not yet fully developed in teneral males, a fact which was not sufficiently taken into consideration by some authors. The present study evaluates the morphological variation of the male genitalia and sound apodemes. Females and nymphs are investigated for taxonomically relevant characters. The study did not yield previously unknown characters particularly for the females and nymphs but suggested that the variation of the male genitalia has previously been underestimated. For this reason K. perplexus Ribaut, 1952 and K. paraltaicus Orosz, 1996 are synonymised with K. strigilifer (Ossiannilsson, 1941) (new synonymies). The base of the female ovipositor is variable within Kybos and separates species groups but does not diagnose species. Nymphs vary in leg dimensions and colour forming the same species groups as the female genitalia but, again, do not diagnose species. In the cladistic analysis the female genital characters make the most important contribution to tree structure whereas the male genitalia are of less importance, contrary to species diagnoses. It is interesting to note that the cladogram comprises a monophyletic group of Betulaceae feeders. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

New species of subterranean Micranops Cameron from the Canary Islands (Coleoptera, Staphylinidae, Paederinae), with a redescription of Micranops bifossicapitatus (Outerelo & Oromí, 1987)

MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 1 2006
Johannes Frisch
Abstract In this contribution, three new anophthalmous species of the genus Micranops (Staphylinidae, Paederinae, Scopaeina) are added to the rich fauna of endogean and troglobitic Coleoptera of the Canary Islands: M. subterraneus sp. n., an endogean species from La Gomera, M. mlejneki sp. n., an endogean species from Tenerife, and M. spelaeus sp. n. from Tenerife, the first troglobitic species within the subtribe Scopaeina. Micranops bifossicapitatus (Outerelo & Oromí, 1987) is transferred from Scopaeus . All species are described, relevant characters are figured, and their niche choice and adaptation to subterranean habitats are discussed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A land snail's view of a fragmented landscape

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009
HEIKE KAPPES
Habitat fragmentation may influence the genetic structure of populations, especially of species with low mobility. So far, these effects have been mainly studied by surveying neutral markers, and much less by looking at ecologically relevant characters. Therefore, we aimed to explore eventual patterns of covariation between population structuring in neutral markers and variation in shell morphometrics in the forest-associated snail Discus rotundatus in relation to habitat fragment characteristics. To this end, we screened shell morphometric variability and sequence variation in a fragment of the mitochondrial 16S rDNA gene in D. rotundatus from the fragmented landscape of the Lower Rhine Embayment, Germany. The 16S rDNA of D. rotundatus was highly variable, with a total of 118 haplotypes (384 individuals) forming four clades and one unresolved group. There was a geographic pattern in the distribution of the clades with the river Rhine apparently separating two groups. Yet, at the geographic scale considered, there was no obvious effect of fragmentation on shell morphometrics and 16S rDNA variation because GST often was as high within, as between forests. Instead, the age of the habitat and (re-)afforestation events appeared to affect shell shape and 16S rDNA in terms of the number of clades per site. The ecologically relevant characters thus supported the presumably neutral mitochondrial DNA markers by indicating that populations of not strictly stenecious species may be (relatively) stable in fragments. However, afforestation after large clearcuts and habitat gain after the amendment of deforestation are accompanied by several, seemingly persistent peculiarities, such as altered genetic composition and shell characters (e.g. aperture size). © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 839,850. [source]

Unstable taxa in cladistic analysis: identification and the assessment of relevant characters

CLADISTICS, Issue 5 2009
Diego Pol
A common problem in phylogenetic analysis is the presence of unstable taxa that are depicted in multiple positions in optimal topologies. These uncertainties are reflected in strict consensus trees with polytomies that hamper the interpretation of the phylogenetic results. We propose a protocol for detecting unstable branches (either terminal taxa or clades) and identifying particular characters related to their instability in cladistic analysis. This procedure is based on an iterative evaluation of the agreement of triplets among the optimal topologies (i.e. most-parsimonious trees, MPTs) and examination of character optimizations on these trees. Different types of characters underlying the unstable behaviour of taxa are detected: those with conflicting scorings that support alternative positions of problematic taxa and those with missing data in the unstable taxa that could reduce their instability if they are scored. The entire process is automated through a TNT script that provides a list of characters related to the instability of each unstable taxon. The outcome of this procedure can be used as a guide for further research efforts focused on the revision or addition of (morphological or molecular) phylogenetic data for elucidating the affinities of unstable taxa. ,© The Willi Hennig Society 2009. [source]