Here is a Agnostid Trilobite of the species Itagnostus interstrictus from the middle Cambrian of Utah. This species till 2012 known as Peronopsis interstricta.
In 2012 Elena Naimark publisched a extensive revision of 116 species of the familie of Peronopsidae. In this publication is the species P. interstricta reassigned to the the Genus Itagnostus Öpik, 1979. It is interesting that Öpik established this taxaon as a subgunus of Peronopsis. The Typespecies was Peronopsis (ltagnostus) elkedraensis (Etheridge Jr,1902).
It appears contradictory because Jell & Adrain, 2002 classify the genus Itagnostus including its type species as a junior synonym of Peronopsis, fide Robison, 1988.
Jell, P.A. & Adrain, J.M. 30 8 2002: Available generic names for trilobites. Memoirs of the
Queensland Museum 48(2): 331-553. Brisbane. ISSN0079-8835.
Naimark, E. B. (2012). Hundred species of the genus Peronopsis Hawle et Corda, 1847. Paleontological Journal, 46(9), 945–1057.doi:10.1134/s0031030112090018
Öpik, A.A., Middle Cambrian Agnostids: Systematics and
Biostratigraphy, Canberra, 1979, pp. 5–187.
Robison 1988. Trilobites of the Holm Dal Formation (late Middle
Cambrian), central north Greenland. Meddelelser
om Grønland, Geoscience 20: 23-103. |
