Isotelus
| Isotelus | |
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| Isotelus brachycephalus | |
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| Genus: | Isotelus
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Isotelus is a genus of asaphid trilobite from the middle and upper Ordovician period, fairly common in the Northeastern United States, northwest Manitoba, southwestern Quebec and southeastern Ontario. One species, Isotelus rex, is currently the world's largest trilobite ever found as a complete fossil.
Discovery and naming
A specimen of Isotelus rex, from Churchill, Manitoba, is the largest complete trilobite ever found. Discovered by Dave Rudkin (Royal Ontario Museum), Robert Elias (University of Manitoba), Graham Young (Manitoba Museum) and Edward Dobrzanske (Manitoba Museum) in 1999, it measures 720 millimetres (28 in) in length, 400 millimetres (16 in) in maximum width (across the cephalon) and 70 millimetres (3 in) in maximum height (at the posterior midpoint of the cephalon).[1][2][3]
Many specimens have also been found in Ohio, where Isotelus maximus is the state fossil.[citation needed] [4]
Description
- Very similar to Homotelus
- “Double” posterior
- Head and tail shields are semi-circular and very similar in shape (isopygus)
- Thorax has 8 segments and a slightly raised middle lobe between the outer pleurae
References
- ^ Rudkin, D.A.; Young, G.A.; Elias, R.J.; Dobrzanske, E.P. (2003). "The World's biggest Trilobite: Isotelus rex new species from the Upper Ordovician of northern Manitoba, Canada". Palaeontology. 70 (1): 99–112. doi:10.1666/0022-3360(2003)077<0099:TWBTIR>2.0.CO;2. ISSN 0022-3360.
- ^ S. M. Gon III (2005-08-17). "The World's Largest Trilobites".
- ^ P. Z. Myers (2005-04-25). "Isotelus rex, biggest trilobite ever".
- ^ http://www.ohiohistorycentral.org/w/Ohio's_State_Fossil_-_Isotelus?rec=1874
