Ancaucha block (Cambrian of Argentina)

Where: Argentina (30.2° S, 68.9° W: paleocoordinates 45.5° S, 125.0° W)

• coordinate estimated from map

When: Bonnia - Olenellus trilobite zone, Ancaucha Olistolith Formation, Dyeran (516.0 - 513.0 Ma)

• formation-level stratigraphic resolution

Environment/lithology: marine; lime mudstone

• The Ancaucha olistolith, which is more than 500 m in length and includes an approximately 80 m thick stratigraphic succession. It starts with a lower reddish clastic interval displaying subaerial or very shallow water structures grading upwards into a mixed clastic-carbonate succession (Astini and Thomas, 1999). The overlying thin layers of bioclastic packstones interbedded with fine-grained clastic sediments have yielded Nisusia ancauchensis n. sp. and poorly preserved orthids probably belonging to Diraphora. Brachiopods are associated with the agmatan Salterella maccullochi (Murchison) and the trilobite Arcuolenellus mega- frontalis, a distinctive species of the Bonnia-Olenellus Zone.

Size class: microfossils

Primary reference: R. A. Astini, W. A. Thomas, and E. L. Yochelson. 2004. Salterella in the Argentine Precordillera: an Early Cambrian palaeobiogeographic indicator of Laurentian affinity. Palaeogeography, Palaeoclimatology, Palaeoecology 213:125-132 [M. Uhen/M. Uhen]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 176949: authorized by Mark Uhen, entered by Mark Uhen on 09.03.2016, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

 Redlichiida - Olenellidae
"Arcuolenellus megafrontalis" = Olenellus megafrontalis
"Arcuolenellus megafrontalis" = Olenellus megafrontalis Vaccari 1988 trilobite
 Kutorginida - Nisusiidae
Nisusia ancauchensis n. sp. Benedetto and Foglia 2012
 Orthida - Bohemiellidae
Salterella maccullochi
  - Salterellidae
Salterella maccullochi Murchison 1859