VI.—Blind Trilobites

Trilobites

Avery’s purification of transforming principle and Kornberg’s purification of the first DNA polymerase, the experiments I have described were of a new type where what might be called the chemical behaviour of genetic material was being analysed without the benefit of purification. And this has become the new style in biology, inaugurated in the late 1950s by Taylor, Meselson and Stahl. It was, ...

Developmental trait evolution in trilobites.

We performed a tree-based analysis of trilobite postembryonic development in a sample of 60 species for which quantitative data on segmentation and growth increments between putative successive instars are available, and that spans much of the temporal, phylogenetic, and habitat range of the group. Three developmental traits were investigated: the developmental mode of trunk segmentation, the a...

The Lifestyles of the Trilobites

Animal Evolution: Trilobites on Speed

A new study quantifies rates of morphological and molecular evolution for arthropods during the critical Cambrian explosion. Both morphological and molecular evolution are accelerated--but not so much to break any speed limits.

Phylogenetic and Biogeographic Analysis of Sphaerexochine Trilobites

BACKGROUND Sphaerexochinae is a speciose and widely distributed group of cheirurid trilobites. Their temporal range extends from the earliest Ordovician through the Silurian, and they survived the end Ordovician mass extinction event (the second largest mass extinction in Earth history). Prior to this study, the individual evolutionary relationships within the group had yet to be determined uti...