Fossil ginkgophyte seedlings from the Triassic of France resemble modern Ginkgo biloba
1 Museum of Nature South Tyrol, Bindergasse 1, Bolzano/Bozen 39100, Italy
2 Department für Geo- und Umweltwissenschaften, Paläontologie und Geobiologie, Ludwig-Maximilians-Universität, Richard-Wagner-Straße 10, Munich 80333, Germany
3 4 Place du Marché aux Poissons, Strasbourg 67000, France
4 Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Straße 10, Munich 80333, Germany
BMC Evolutionary Biology 2013, 13:177 doi:10.1186/1471-2148-13-177Published: 27 August 2013
Fossil evidence of ginkgophyte ontogeny is exceedingly rare. Early development in the extant Ginkgo biloba is characterized by a series of distinct ontogenetic stages. Fossils providing insights into the early ontogeny of ancient ginkgophytes may be significant in assessing the degree of relatedness between fossil ginkgophytes and G. biloba.
An assemblage of seedlings from the early Middle Triassic of France is assigned to the ginkgophytes based on leaf morphology. The specimens represent an ontogenetic sequence consisting of four stages: (I) formation of the cotyledons in the seed and germination; (II) development of primary leaves and taproot; (III) thickening of the taproot and appearance of secondary roots; and (IV) development of the first differentiated leaves and absence of the seed remnants.
The fossil seedlings provide a rare opportunity to examine the early ontogeny of a Triassic ginkgophyte. Germination and seedling development in the fossil are nearly identical to that of the extant gymnosperm G. biloba. We hypothesize that the fossil may be closely related biologically to G. biloba, and that certain developmental processes in seedling development were in place by the Middle Triassic.