The fossil record demonstrates that each major taxonomic group has a consistent net rate of diversification and a limit to its species richness. It has been thought that long-term changes in the dominance of major taxonomic groups can be predicted from these characteristics. However, new analyses show that diversity limits may rise or fall in response to adaptive radiations or extinctions. Thes...

The ITS region from a wide taxonomic range of nematodes, including secernentean and adenophorean taxa, and free-living, entomopathogenic, and plant-parasitic species, was evaluated as a taxonomic marker. Size of the amplified product aided in the initial determination of group membership, and also suggested groups that may require taxonomic reevaluation. Congeneric species often displayed ident...

In the original description of the index, S i is the number of taxa in the given clade and rank after the study. The meaning of “number of taxa” must be the number of valid taxa in this context. This suggests that the number of taxa can only be higher after the taxonomic revision. However, synonyms are abundant in most taxonomic groups in various proportion (May & Nee 1995; Patterson 1996). Syn...

For 120 specimens and fi gures of Fragilariforma, 10 Legendre coeffi cients were calculated as shape descriptors. For each half valve apically bisected, 50 x,y coordinates were used to calculate Legendre coeffi cients. Principal components analysis (PCA) was used to ordinate the shape descriptors as a total shape gradient of valve forms. The fi rst four principal components explained 90.3 % of ...

Microbial communities can display large variation in taxonomic composition, yet this variation can coincide with stable metabolic functional structure and performance. The mechanisms driving the taxonomic variation within functional groups remain largely unknown. Biotic interactions, such as predation by phages, have been suggested as potential cause of taxonomic turnover, but the conditions fo...

BACKGROUND The arthropod class Diplopoda is a mega-diverse group comprising >12,000 described millipede species. The history of taxonomic research within the group is tumultuous and, consequently, has yielded a questionable higher-level classification. Few higher-taxa are defined using synapomorphies, and the practice of single taxon descriptions lacking a revisionary framework has produced man...

Rapid development of broad regional and international DNA barcode libraries have brought new insights into the species diversity of many areas and groups. Many new species, even within well-investigated species groups, have been discovered based initially on differences in DNA barcodes. We barcoded 437 collection specimens belonging to 40 pre-identified Palearctic species of the Elachista bifas...