Itagnostus

Itagnostus is a genus of trilobite restricted to the Middle Cambrian. Its remains have been found in Asia, Australia, Europe, and North America.[1]

Itagnostus
Temporal range: earliest Mayan to earliest Batyrbayan
Itagnostus interstrictus, until recently known as Peronopsis interstricta, from the Wheeler Shale, Utah
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Trilobita
Order:
Agnostida
Family:
Peronopsidae
Genus:
Itagnostus

Öpik, 1979
species[1]
  • I. elkedrensis (Etheridge, 1902) (type)
  • I. comis (Öpik, 1979)
  • I. doylei (Laurie, 2006)
  • I. gaspensis (Rasetti, 1948)
ssp. gaspensis
ssp. taitzuhoensis (Lu, 1957)
  • I. interstrictus (White, 1874) synonyms Euagnostus levifrons, Peronopsis interstricta
ssp. interstrictus
ssp. robustus (Deiss, 1939) synonym Agnostus robustus
  • I. krusei (Laurie, 2006)
  • I. oepiki (Laurie, 2004)
  • I. subhastatus (Geyer & Peel, 2017)
  • I. walleyae (Laurie, 2006)

Distribution
  • Itagnostus elkedrensis occurs in the Middle Cambrian of Australia (Ptychagnostus praecurrens-zone, Xystridura templetonensis-zone, and Dinesus-stage, Elkedra; Triplagnostus gibbus-zone, Sandover Beds; both Northern Territory), the Russian Federation (Kounamkites-zone, Nekekit River; Liostracus allachjunensis-zone, Lena River).
  • Itagnostus comis is found in the Middle Cambrian of Australia (Triplagnostus gibbus-zone, Sandover Beds, Northern Territory).
  • Itagnostus gaspensis gaspensis is reported from the Middle Cambrian of the United States (Geddes Formation, Nevada; Ptychagnostus atavus-zone, Wheeler Formation, Drum Mountains, Utah), Canada (upper part, Grosses Roches, St. Laurence, Quebec), Russian Federation (Tomagnostus fissus-zone, Lena River).
  • Itagnostus gaspensis taitzuhoensis has been excavated from the Middle Cambrian of Antarctica (lower part, Shackleton Mountains), Australia (Ptychagnostus praecurrens-zone, Elkedra, Northern Territory), North-China (Bailiella-Lioparia-zone, Hsuchang Formation).
  • Itagnostus interstrictus interstrictus is present in the Middle Cambrian of Canada (Ptychagnostus punctuosus-zone, Cow head Group, Newfoundland), the United States (Bolaspidella (P. atavus)-zone, Tatonduk River, Hillard Peak, Alaska; lower part of the Bolaspidella-zone, Western-Utah; Wheeler Shale, Antelope Spring, House Range, Utah), the Russian Federation (Malokuonamsky Horizon, Tomagnostus fissus-zone, and Liostracus allachjunensis-zone, all Lena River).
  • Itagnostus krusei is found in the Middle Cambrian of the Russian Federation (Kounamkites-zone, Lena River).
  • Itagnostus oepiki has been collected in the Middle Cambrian of Australia (Triplagnostus gibbus-zone, Sandover Beds; Xystridura templetonensis-zone, Elkedra; both Northern Territory).
  • Itagnostus walleyae is reported from the Middle Cambrian of Australia (Ptychagnostus praecurrens-zone, Elkedra, Northern Territory).
  • Itagnostus sp. has been collected in the Middle Cambrian of the Russian Federation (Liosttracus allachjunensis-zone, Lena River).[1]
Schematic showing the relationship between Itagnostus (light green) with other Peronopsid genera (darker green). The descending genus Euagnostus (Dorypygidae) is shown in blue-purple

References
  1. Naimark, E.B. (2012). "Hundred species of the Genus Peronopsis Hawle et Corda, 1847". Paleontological Journal. 46 (9): 945–1057. doi:10.1134/S0031030112090018. S2CID 85130465.
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