| Itagnostus 
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| Itagnostus interstrictus, until recently known as Peronopsis interstricta, from the Wheeler Shale, Utah | 
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| Genus: | Itagnostus 
 Öpik, 1979 | 
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| species | 
| I. elkedrensis (Etheridge, 1902) (type)I. comis (Öpik, 1979)I. doylei (Laurie, 2006)I. gaspensis (Rasetti, 1948)
 ssp. gaspensisssp. taitzuhoensis (Lu, 1957)
 I. interstrictus (White, 1874) synonyms Euagnostus levifrons, Peronopsis interstricta
 ssp. interstrictusssp. robustus (Deiss, 1939) synonym Agnostus robustus
 I. krusei (Laurie, 2006)I. oepiki (Laurie, 2004)I. subhastatus (Geyer & Peel, 2017)I. walleyae (Laurie, 2006)
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Itagnostus is a genus of trilobite restricted to the Middle Cambrian. Its remains have been found in Asia, Australia, Europe, and North America.