Organismal taxonomy is often based on a single or a small number of morphological
characters. When they are morphologically simple or known to be plastic, we may not have …

Although calyptraeid gastropods are not well understood taxonomically, in part because
their simple plastic shells are the primary taxonomic character, they provide an ideal system …

Traditionally, gastropod classification and phylogeny are often based on hardshell
structures, although other anatomical char-acters and molecular characters are increas-ingly …

Both molecular and morphological data can be used for constructing branching diagrams
indicative of phylogeny. The question 'Is it feasible to combine different data sets into a …

Using fossils to study speciation requires careful analysis of the potential and limits of both
biological and geological data. The most important biological data for a particular taxon …

Most groupings on the tree of life were first inferred using morphological characters, which
have been widely used since Darwin's time. Most of the million-plus described species are …

Despite being the objects of numerous macroevolutionary studies, many of the best
represented constituents of the fossil record—including diverse examples such as …

Taxonomists specializing in different groups once based phylogenetic analysis only on
morphological data; molecular data was used more rarely. Although molecular systematics …

Because phytogenies play a central role in many evolutionary and population genetic
questions, it is vital to have confidence in phylogeny reconstructions for particular data sets …

Some generally accepted viewpoints on the phylogenetic relationships within the molluscan
class Gastropoda are reassessed by comparing complete 18S rRNA sequences …