Ischyrotoma Raymond 1925 (trilobite)

Trilobita - Proetida - Dimeropygidae

Full reference: P. E. Raymond. 1925. Some trilobites of the lower Middle Ordovician of eastern North America. Bulletin of the Museum of Comparative Zo├Âlogy at Harvard College 67(1):1-180

Parent taxon: Dimeropygidae according to R. A. Fortey and D. L. Bruton 2013

See also Fortey and Droser 1999, Jell and Adrain 2002, Raymond 1925 and Sepkoski 2002

Sister taxa: Bearriverops, Chomatopyge, Dimeropyge, Dimeropygiella, Heckethornia, Mesotaphraspidinae, Mesotaphraspis, Pseudohystricurus, Toernquistia, Tulepyge, Toernquistina

Subtaxa: Ischyrotoma anataphra Ischyrotoma borealis Ischyrotoma eos Ischyrotoma juabensis Ischyrotoma parallela Ischyrotoma sila Ischyrotoma stubblefieldi Ischyrotoma twenhofeli Ischyrotoma wahwahensis

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Type: Ischyrotoma twenhofeli

Ecology: fast-moving low-level epifaunal deposit feeder


• Chazyan of Canada (1: Newfoundland and Labrador collection)

• Whiterockian of Canada (1: Newfoundland and Labrador), Norway (1), United States (5: Nevada, Utah)

• Arenig of Greenland (1), United States (1: New York)

• Arenigian of Canada (1: Northwest Territories)

• Ordovician of Canada (27: Newfoundland, Newfoundland and Labrador, Nunavut, Quebec), China (1), Norway (4), the United Kingdom (1), United States (46: California, Nevada, Oklahoma, Utah)

• Tremadoc of Canada (2: Alberta)

Total: 92 collections including 100 occurrences

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