Middle Triassic

What happened during this time?

Biological

Flora

• Ecosystems begin to recover from the end-Permian extinction during the Olenekian (late Early Triassic), and continue into the Middle Triassic

• Corystosperms are a major plant in Triassic ecosystem; index fossil 

  • By the middle Triassic, they replace glossopterids in the flora

• Horsetails, ferns, seed ferns, conifers, and cycads (Labandeira 1998). 

  • The conifers radiated, covering broad areas with open forests. 

  • Conifer domination remained the general pattern through the remainder of the Triassic and Jurassic Periods. 

Fauna

• True flies (dipteran insects) had appeared in the Early Triassic. 

  • They radiated with the recovery of the terrestrial plants

  • Middle Triassic saw the divergence of the fruit fly and mosquito lineages (Benton & Donoghue 2007). 

• Other herbivorous insects also established themselves in the new forests, such as beetles, hemipterans, and an unknown insect which left cicada-like burrows (Labandeira 1998). 

• Temnospondyl amphibians remained an important element in swamp and fresh water settings

• The existence of basal frogs and salamanders is likely

• Earliest evidence of of dinosaurs: Nyasasaurus  from 243 Ma is the oldest known dinosaur (Nesbitt et al. 2013)

Geophysical

• Oxygen levels hover around 24-25%

• Carbon dioxide levels hover around 650 ppm

• South America and Africa were still connected

• Split forms between Africa and Eurasia, 

• India and Australia were attached to Antarctica