A multivariate approach to treatment of anatomical characters has facilitated the discrimination among very similarly shaped species, aided by behavioral and ecological evidence.

Troodontids are important in research into the origin of birds because they share many anatomical characters with early birds.

The two genera are distinguished only by internal anatomical characters.

Apparently, specific differences exist in the penial complex, but present data are insufficient to allow any recognition of species groups through anatomical characters.

The teeth themselves may look normal and do not have any particular anatomical character on clinical examination.

The anatomical characters of the Neomphaloidea largely follow the patterns as in the Vetigastropoda.

However, it is expandable both taxonomically and in regard to anatomical or molecular characters.

This was based on anatomical characters and a dataset of molecular sequences of three gene fragments.

A few anatomical characters unite the Orycteropodidae and Tubulidentata.

Molecular genetic studies revealed the traditional classification, based on morphological and anatomical characters, often did not reflect the phylogenetical relationships.