Baiera (Baiera australis)

Baiera australis - Cretaceous Ginkgoaceous Leaf Fossil

Reconstructed from fossilized leaves found in Victoria, Baiera australis remains a pivotal taxon for understanding Cretaceous gymnosperm evolution. Originally described by McCoy in 1892, this species represents the basionym for the widely recognized southern ginkgo fossil, Ginkgo australis. Its preservation in coal measures provides critical data on the prehistoric vegetation of South Gippsland.

Taxonomy

Morphology

Specimens demonstrate robust, deeply cleft leaves with a prominent petiole. The lamina divides repeatedly into narrow, wedge-shaped lobes, each containing parallel dichotomous veins. Cuticular analyses of related specimens suggest a thick cuticle with haplocheilic stomata, suggesting a resilience to fluctuating atmospheric conditions during the Mesozoic.

Interesting facts

This fossil species provides valuable insights into the geographical distribution of the Ginkgoaceae family during the Mesozoic era. Notable details include:

  • Basionym Status: McCoy originally established the species under the genus Baiera before it was later reassigned to Ginkgoites and eventually Ginkgo.
  • Fossil Bed Association: It is predominantly found in the Koonwarra and Bald Hill deposits, which are famous for their exceptional preservation of early Cretaceous life.
  • Gondwanan Connection: The species demonstrates that the Ginkgoaceae family was widespread and diverse across the southern supercontinent before continental drift.

Geography of distribution

  • Австралия (штат Виктория, формация Корумбурра)

Sources

  • Drinnan, A.N. & Chambers, T.C. (1986). Flora of the Lower Cretaceous Koonwarra Fossil Bed (Korumburra Group), South Gippsland, Victoria. Memoirs of the Association of Australasian Palaeontologists, 3, 1–77.