Search A Guide to the Orders of Trilobites THIS SITE OPTIMIZED FOR VIEWING AT 1024 X 768 RESOLUTION In these pages, you may recognize species that are common, well-known, or sitting in a familiar museum collection! This guide might help you arrange trilobite diversity systematically, aid in identification of specimens, and enhance your understanding of these fascinating elements of Paleozoic biodiversity.  Happy browsing!  -- Sam Gon III

Trilobite Order Fact Sheets detailed, descriptive characters and representative line drawings  Click on any of the images above to be sent to a page featuring details on trilobites in that Order ...

Trilobite Order Galleries trilobite images from various locations on the web, arranged by order Agnostida Redlichiida Corynexochida Odontopleurida Lichida Phacopida Proetida Asaphida Harpetida Ptychopariida Click on any of the images above to be sent to a gallery featuring photos of trilobites in that Order

Asaphus kowalewski Order Asaphida	SOURCES: The information in these pages was developed via examination and synthesis of the data present in a variety of works, including the two "Trilobite Treatises:" Moore 1959 (Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, including Trilobitomorpha) and Whittington et al 1997 (Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita, Revised, Volume 1: Introduction). Both may be reviewed here. Other important sources are cited in specific pages of this site, and are also listed in a brief bibliography. Sources of photos and line drawings (where not original) are clearly cited. Other trilobite web sites and individuals were inspirational sources and are cited where relevant. The three trilobite thumbnail images in the left column, for example, are c/o Andrew Milner. If you find your information or images on these pages without proper attribution, this is unintentional. Please contact me to rectify the situation.
Elrathia kingi Order Ptychopariida	CAVEATS: Information about extinct animals is always subject to interpretation and differences of opinion. In particular, the higher classification of arthropods and trilobites is neither simple nor agreed upon by all trilobite workers. The summaries here are complicated by the fact that the 1997 revision of the Treatise only covers two orders in detail: Agnostida and Redlichiida. The others are in preparation, so my attempts to synthesize data on the other orders is likely to be incomplete, although the arrangement of the families and some characteristic descriptions were provided by Fortey (in Whittington et al 1997), and adjusted via recent articles (e.g., papers dealing with higher classification of the Asaphida, Proetida, Harpetida, Agnostida, and Lichida). Additional revisions continue to be suggested by various workers. Any errors in the information here should be attributed to the compiler, Sam Gon III. Please inform him of any problems in accuracy or interpretation.
.... Sthenarocalymene celebra Order Phacopida	ABOUT THE AUTHOR: This site's pages (and the majority of its figures) were designed and created by Dr. Sam Gon III, a biologist (PhD, Animal Behavior; MA, Zoology (Ecology, Behavior and Evolution) who is greatly intrigued by the expression of ancient biodiversity that trilobites represent. Sam's professional work is in the conservation of global biodiversity today. He serves as the Senior Scientist for The Nature Conservancy's Hawai‘i Field Office in Honolulu. Sam has long been interested in paleobiology, and in teaching himself about trilobites, using hyperlinks to cross-reference terminology and concepts, found himself developing a web resource of potential interest to a broader audience. The 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.

A Guide to the Orders of Trilobites A website devoted to understanding trilobites created and maintained by Sam Gon III walking trilobite ©2000 This image anywhere on this site goes to the main menu This award-winning website now available in book form! SEARCH THIS WEBSITE TRILOBITE OF THE MONTH -- FEBRUARY 2019 . Brachyhipposiderus antiquatus Zhu 2005 Sandu Fm., U. Cambrian (Furongian) Guole, SW Guangxi Prov., China Image courtesy of Marc R. Hänsel The Trilobite of the Month for February 2019 is classified as a primitive member of Order Harpetida from the Late Cambrian. It was a time when many of the more advanced trilobites were beginning to distinguish themselves from the primitive Redlichida and Ptychopariida, so we can sometimes see intriguing characteristics that suggest the affinities of the different orders. This complete specimen of Brachyhipposiderus, for example has a thorax and pygidium that is rather reminiscent of trinucleids, and its cephalic shape is also reminiscent of the trinucleid fringe, lacking the well-developed tall genal prolongations of advanced harpetids. Images like this help explain why trilobites are one of the best-known and appreciated groups of prehistoric animals. Each month, a new example of trilobite diversity will be showcased here. With over 20,000 described species, we may never exhaust the possibilities! If you have a stunning image of a trilobite that you could share as a future "Trilobite of the Month," please let me know! 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.  Maurotarion christyi via Marc Behrendt.
Fact Sheets		Click on the images, menu choices, or the FAQ listings below on this page to start exploring aspects of trilobite biology, and the salient characters that define the orders, constituent suborders, and superfamilies. This site has enjoyed feedback from a growing number of trilobite workers from all over the world who have generously offered their suggestions and corrections. I gratefully acknowledge their help and encouragement. This website protected by copyright ©1999 - 2018 by S. M. Gon III The Trilobite FAQ Use the links on the right to answer the Qs on the left Unfamiliar with trilobites altogether? Introduction to Trilobites What are trilobite body parts called? Trilobite Dorsal Morphology Unfamiliar with trilobite undersides? Trilobite Ventral Morphology What about the inside of a trilobite? Trilobite Internal Anatomy What was special about trilobite eyes? Trilobite Eyes & Vision Want definitions of trilobite terms? Glossary of Trilobite Terms How are the trilobite orders related? Trilobite Systematic Relationships Want a list of all trilobite families? Phylogenetic List of Trilobite Families Want a list of all trilobite genera? List of 5000 Trilobite Generic Names How long ago did trilobites exist? Geological Time relevant to Trilobites Can trilobites help determine geological time? Trilobite Biostratigraphy What ecological roles did trilobites play? Trilobite Ecology and Environments How do we know about trilobite behavior? Trilobite Trace Fossils What and how did trilobites eat? Trilobite Feeding Habits How did trilobites reproduce and grow? Trilobite Reproduction & Development What roles did sutures play in molting? Trilobite Sutures & Molting What about trilobite bumps and spines? Trilobite Prosopon How did trilobites defend themselves? Trilobite Enrollment & Coaptation How did trilobites evolve? Trilobite Evolutionary Trends What is the origin of trilobites? Trilobites Origins What were the first trilobites? The First Trilobites What were the last trilobites? Trilobite Extinction Did trilobites show any signs of disease? Trilobite Abnormalities Didn't I see a living trilobite? Trilobite Imposters Where in the world are trilobites found now? World Trilobite Localities How did the Earth look when trilobites lived? Trilobite Paleogeography Think you know about trilobites now? Take the Trilobite Identification Quiz! How big did trilobites get? World's Largest Trilobites How do you prepare a trilobite fossil? Trilobite Preparation Is this site available in hardcopy form? Yes! Preview the folio pages here Are there many books on trilobites? Review recommended trilobite books! Found mistakes or refinements needed? Please tell me about them SEARCH THIS WEBSITE