Orestovia
- Barzas Formation ( Russia)
- Xichong Formation ( China)
- Orestovia devonica Ergolskaya
Orestovia is a fully terrestrial species, vegetative organisms from the Devonian of Russia and China. It is in the form of fossil stem axis in the early - and mitteldevonischen coal formations of West Siberia and southern China. The genus and its only way Orestovia devonica were first described in 1936 by ZV Ergolskaya. Because they have some structures in common with plants, it is made by some palaeobotanists in their close relationship. Others propose to the brown algae or look at them as a link between plants and brown algae.
Features
Orestovia fossils are naked, unbranched, cutinisierte axes of up to 20 cm in length and 26nbsp; cm wide, tapering towards the tip. Most specimens are preserved as hollow cuticular sheaths which often have an epidermis- like cellular pattern. Most other parts of the fabric, however, are not fossilized. Due to the axes a delicate strand of tracheids with annular -like tubes pulls up reticulate thickenings on the inside of the walls. Many tubes contain a central core, which is interpreted as a resin. Are irregular swellings that are associated with a secretory function on the outer side of the axes. About the axes of small, sunken pores are distributed, which are surrounded by a plurality of rings of cells or cell-like structures. These structures are interpreted as stomatal apparatus.
In some instances spores were found in the bark of the axes that have a size from 150 to 190 microns. On the cuticle fungi were found.
System
Orestovia devonica was first described by ZV Ergolskaya 1936 köhlernen Barzas the formation of Western Siberia. The genus names they chose in honor of VA Orestov, the epithet devonica takes on the age of the fossil reference. It is sometimes interpreted as a vascular plant of unknown kinship affiliation. A reconstruction provides Orestovia, similar to the extant fern Pilularia globulifera (Family Marsileaceae ). with a creeping rhizome and located in the water naked, upright axes.