Palaeobiogeography of Devonian and Carboniferous crinoid faunas of Gondwana

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - Devonian and Carboniferous crinoid faunas of Gondwana are generally not as large or well known as faunas from Laurentia and Baltica. Devonian faunas are known from three regions in Gondwana: Northern Africa (Morocco and Algeria), eastern Australia, and the southwestern edge of Gondwana in a belt extending from the Karoo Basin of South Africa through West Falkland Island into the Chaco Basin of Argentina and Bolivia, into Columbia. Most faunas are of Early Devonian age, mostly Emsian. No faunas are recognized from the Frasnian and only one specimen has been referred to questionable Famennian strata. Australian and Northern Africa faunas show closer affinity to Baltica faunas at the generic level. The Australian and southwestern edge Gondwanan faunas have the most endemic genera. These may be cold water Devonian faunas or they may support a generally warmer global climate for the Devonian as the southwesten edge faunas were living at 60° to 85° S latitude.

Early Carboniferous crinoid faunas are known from Northern Africa, India, eastern Australia, and South America. Most faunas are of late Tournaisian or Visean age and dominated by camerates. Early Tournaisian and Namurian faunas are few. All known faunas lived within 35° of the palaeoequator and are judged to be warm water faunas. Two endemic genera are recognized in the Australian fauna and one in the Indian fauna.

Late Carboniferous Westphalian faunas are known from Brazil, Algeria, Pakistan, and eastern Australia. Stephanian faunas are unknown. Faunas are dominated by poteriocrininids. The Brazilian and Algerian warm water faunas were living within 30° of the palaeoequator while the Australian fauna from Queensland was living between 45° and 50° S latitude. The Australian fauna is considered a cooler water fauna that lived in a slightly warmer interglacial between Gondwana Carboniferous glaciations. One endemic genus is recognized in the Algerian fauna and three endemic genera are recognized in the Queensland fauna.