how big were trilobites
Trilobites are the single most diverse group of extinct organisms that ever existed, period! The smallest known trilobite is just three millimeters long, while the largest type grew to a length of 70 centimeters (over two feet long!).
The earliest trilobites known from the fossil record are fallotaspids, and redlichiids (both order Redlichiida) and bigotinids (order Ptychopariida, superfamily Ellipsocephaloidea) dated to some 540 to 520 million years ago.ecause trilobites had wide diversity and an easily fossilized exoskeleton an extensive fossil record was left behind, with some 17,000 known species spanning Paleozoic time. The study of these fossils has facilitated important contributions to biostratigraphy, paleontology, evolutionary biology and plate tectonics.