Tuesday, February 14, 2012

Sam Gon III Guide to the Trilobites

Dr Sam Gon III "serves as the Senior Scientist for The Nature Conservancy's Hawai‘i Field Office in Honolulu... The [Web] site was first unveiled in August 1999 and has attracted feedback from around the world, generating ongoing updates. For all the accolades this site has gathered, Sam is not a professional trilobitologist, but a devoted trilobitophile! In 2006 this culminated in his first paleontological publication, dealing with trilobite origins."
From about the author page

Sam Gon III has created a comprehensive, very interesting, highly recommended, and publicly rewarded science site

Guide to the Orders of Trilobites 
and invites us to their fascinating world with these introductory words:

"Trilobites are the most diverse group of extinct animals preserved in the fossil record. Ten orders of trilobites are recognized, into which 20,000+ species are placed.
  • Learn more about trilobite morphology, anatomy, ecology, behavior, reproduction, and development, and how they relate to trilobite origins, evolution, and classification. 
  • Explore trilobite biostratigraphy, paleobiogeography, persistence across geological time, and their ultimate extinction. 
  • View galleries of trilobite images from the web, examine fact sheets, pictorial guides, and an identification key for each order, 
  • refer to a family listing, a genus listing, 
  • or consult a trilobite glossary and bibliography, 
  • tour world famous trilobite localities, 
  • explore links to other web resources on trilobites, 
  • and review books on trilobites, including an exclusive hardcopy pictorial adaptation of this website."

Period of the trilobites
"The first appearance of trilobites defines the start of Series 2 of the Cambrian (521 mya), and they can be found in strata up to the upper Permian (251 mya), after which trilobites (among a large number of marine organisms) went extinct in the great catastrophe that removed over 90% of all species on earth.

The Great Permian Extinction marks the end of the Paleozoic and the start of the Mesozoic.

Trilobites are one of the few major groups of organisms that span the majority of the Paleozoic Era. The greatest numbers of trilobite species occurred during the Cambrian and Ordovician periods, after which trilobite extinction trends exceeded radiation events.

Toward the end of the Devonian most of the families and orders of trilobites were gone. There were much fewer species in the lone surviving order Proetida in the Carboniferous and Permian periods.

Nevertheless, to have persisted for nearly 300 million years is a testimony to the successful design and adaptability of trilobites. Some scientists even hold out the faint hope that in poorly explored deep sea environments, trilobites may still exist, a holdover from truly ancient times."
From the Geotime page

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