Itagnostus

{{Short description|Extinct genus of trilobites}}

{{Italic title}}

{{Taxobox

| name = Itagnostus

| fossil_range = {{fossilrange|508|497|earliest Mayan to earliest Batyrbayan}}

| image = Itagnostus interstrictus - Wheeler Schale, Utah, USA - Cambrian period (≈ -507 MA) - 39.25°N 113.33°W .jpg

| image_caption = Itagnostus interstrictus, until recently known as Peronopsis interstricta, from the Wheeler Shale, Utah

| regnum = Animalia

| phylum = Arthropoda

| classis = Trilobita

| ordo = Agnostida

| familia = Peronopsidae

| genus =Itagnostus

| genus_authority = Öpik, 1979

| subdivision_ranks = species

| subdivision =

  • 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)

}}

Itagnostus is a genus of trilobite restricted to the Middle Cambrian. Its remains have been found in Asia, Australia, Europe, and North America.{{cite journal|last= Naimark|first= E.B.|year= 2012|title= Hundred species of the Genus Peronopsis Hawle et Corda, 1847|journal= Paleontological Journal|volume= 46|issue= 9|pages= 945–1057|doi= 10.1134/S0031030112090018|bibcode= 2012PalJ...46..945N|s2cid= 85130465}}

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).

Image:Gradogram Itagnostus.jpg

References

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