• journal_title：Journal of Paleontology
• Contributor：Luis A. Buatois ; María Gabriela Mángano
• Publisher：Paleontological Society
• Date：2012-
• Format：text/html
• Language：en
• Identifier：10.1666/11-001.1
• journal_abbrev：Journal of Paleontology
• issn：0022-3360
• volume：86
• issue：1
• firstpage：7
• section：ARTICLES

An early Cambrian ichnofauna consisting of <span class="named-content genus-species" id="named-content-1">Helminthoidichnites tenuisspan>, <span class="named-content genus-species" id="named-content-2">Helminthopsis tenuisspan>, <span class="named-content genus-species" id="named-content-3">Multinaspan> isp., <span class="named-content genus-species" id="named-content-4">Oldhamia alataspan>, and <span class="named-content genus-species" id="named-content-5">Pilichnusspan> cf. <span class="named-content genus-species" id="named-content-6">dichotomusspan> is documented from shallow-marine deposits ranging from the upper offshore to the offshore transition in the Puncoviscana Formation of northwest Argentina. Although the ichnogenus <span class="named-content genus-species" id="named-content-7">Oldhamiaspan> is more common in Cambrian deep-marine environments, this occurrence provides further evidence that it is also present in shallow-marine environments. The burrow network <span class="named-content genus-species" id="named-content-8">Multinaspan> (senior synonym of <span class="named-content genus-species" id="named-content-9">Olenichnusspan>) is preserved at the base of tempestites, representing the activity of post-storm colonizers. A drowning surface separating offshore-transition deposits below from upper-offshore deposits above contains widespread evidence of trace fossils in direct association with matgrounds. The undermat miners <span class="named-content genus-species" id="named-content-10">Oldhamia alataspan> and <span class="named-content genus-species" id="named-content-11">Pilichnusspan> cf. <span class="named-content genus-species" id="named-content-12">P. dichotomusspan> occur on this surface, revealing exploitation of organic matter in the biomat. Low sediment rate during drowning and paucity of bioturbation by sediment bulldozers may have promoted the establishment of the matground. In comparison with the simpler animal-matground interactions characteristic of the Ediacaran, the combination of Cambrian evolutionary innovations and the presence of microbial mats promoted more sophisticated interactions. Complex feeding trace fossils revealing that systematic undermat mining, as displayed by <span class="named-content genus-species" id="named-content-13">Oldamia alataspan> and <span class="named-content genus-species" id="named-content-14">Pilichnusspan> cf. <span class="named-content genus-species" id="named-content-15">dichotomusspan>, is a product of the Cambrian explosion.