A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal

No abstract

No abstract

Most Antarctic archaeocyaths have been collected as allochthonous blocks, but in situ collections from the Shackleton Limestone in the vicinity of Nimrod and Byrd Glaciers (Transantarctic Mountains) provide stratigraphic control. Collections from King George Island, the Weddell Sea, Whichaway Nunataks, Argentina Range, Beardmore Glacier, Nimrod Glacier and Byrd Glacier (Cracking Cwm) are all of Botomian age according to the Siberian stage scale for the Early Cambrian. One collection from the Byrd Glacier (Mt Egerton) may be of slightly younger, Toyonian age. A unique species from the Minaret Formation in the Heritage Range has a Late Cambrian (Idamean) age, and is the youngest archaeocyath known. All existing collections are taxonomically revised here. Strong faunal affinities are evident at the species level with in situ Early Cambrian faunas in South Australia and allochthonous faunas in the Permo-Carboniferous Dwyka Tillite of South Africa. This allows the recognition of an Early Cambrian Gondwana province and confirms the existence of a Gondwana supercontinent throughout the Palaeozoic. Archaeocyatha are the most abundant and characteristic early Palaeozoic macrofossils of the Antarctic continent (Fig. 1). Most Antarctic collections have been recovered as allochthonous blocks in moraine or in dredgings at sea, but some in situ faunas are now known. To date, the only in situ collections studied in detail are from the Shackleton Limestone in the environs of the Nimrod and Byrd Glaciers, Transantarctic Mountains (Debrenne & Kruse 1986). On the basis of this latter work, we here make critical comparisons (and synonymies where necessary) of the faunal lists of previous authors to tentatively establish the composition of the Antarctic archaeocyathan fauna (Figs 2–4).