Dicroidium

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Dicroidium
Temporal range: Triassic
Scientific classification
Kingdom: Plantae
Division: Pteridospermatophyta
Order: Pteridospermales
Family: Corystospermaceae
Genus: Dicroidium
Gothan (1912)
Species

See text

Dicroidium is an extinct genus of fork-leaved seed ferns that were distributed over Gondwana during the Triassic (252 to 201 million years ago). Their fossils are known from South Africa, Australia, New Zealand, South America and Antarctica. They were first discovered in Triassic sediments of Tasmania by Morris in 1845.[1]

Description[edit]

The leaves were essentially like those of modern ferns however they were forked; giving the appearance of two fern leaves joined at the base. It seems that they were deciduous trees. These plants had male and female reproductive structures. Before awareness that they belonged to the same species, male pollen-bearing specimens were named Pteruchus and the female structures Umkomasia.[2]

Species[edit]

  • Dicroidium crassinervis
  • Dicroidium coriaceum, South Africa
  • Dicroidium dubium
  • Dicroidium elongatum, Australia
  • Dicroidium odontopteroides, Brasil in Paleorrota geopark.[3]
  • Dicroidium spinifolium
  • Dicroidium stelznerianum, Argentina, New Zealand[4]
  • Dicroidium zuberi, Antarctica, Australia, South Africa and Brasil in Paleorrota geopark.[5]
  • Dicroidium sp. A.

References[edit]

  1. ^ http://www.qm.qld.gov.au/~/media/Documents/QM/About%20Us/Publications/Memoirs%20-%20Nature/N52-2/52-2-anderson-et-al.pdf
  2. ^ http://www.fossilmuseum.net/plantfossils/Umkomasia/Umkomasia.htm
  3. ^ THE TRIASSIC TAPHOFLORA FROM PARANA BASIN, SOUTHERN BRAZIL
  4. ^ Journal of the Royal Society of New Zealand, March 1985
  5. ^ Passo das Tropas, Santa Maria, RS Marco bioestratigráfico triássico na evolução paleoflorística do Gondwana na Bacia do Paraná.
  • Bomfleur, B. and Kerp, H. (2010). Dicroidium diversity in the Upper Triassic of north Victoria Land, East Antarctica.