Proetida - a new order of trilobites

A new order of trilobites - the Proetida - is proposed to include the families Aulacopleuridae , Bathyuridae, Brachymetopidae, Celmidae, Dimeropygidae, Glaphuridae, Otarionidae and Proetidae, based on study of a wide range of material of these families. This is believed to be a more natural grouping of these families than that currently adopted. The supposed relationships of these trilobites are based on a comparison of morphological features and ontogenies; new discoveries of early species are consistent with this conclusion. The families are considered to have been derived from various species of the subfamily Hystricurinae, probably during the Tremadoc, from which evolution may have subsequently proceeded along relatively independent lines. Parallelism of morphological features in different groups of the Proetida indicate the repeated adoption of similar life habits.