Margaretia is a frondose organism known from the middle Cambrian Burgess shale and the Kinzers Formation of Pennsylvania.[1] Its fronds reached about 10 cm in length and are peppered with a range of length-parallel oval holes. It was originally interpreted as an alcyonariancoral.[2] It was later reclassified as a green alga closely resembling modern Caulerpa by D.F. Satterthwait in her Ph.D. thesis in 1976,[3] a finding supported by Conway Morris and Robison in 1988.[2] More recently, it has been treated as an organic tube, that is used as nest of hemichordateOesia.[4]
^ abS.Conway Morris and R.A. Robison, "More soft-bodied Animals and Algae from the Middle Cambrian of Utah and British Columbia", University of Kansas Paleontological Contributions, Paper 122, pages 8-11, 1988. [1]
^Donna Fields Satterthwait, Paleobiology and Paleoecology of Middle Cambrian Algae from Western North America, Ph.D. Thesis University of California at Los Angeles, 1976.