Tarella
| Tarella | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Early Devonian ( Pragium ) | ||||||||||||
| 411 to 407 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Tarella | ||||||||||||
Tarella is a genus of extinct plants that are known from the Devonian and belong to the Zosterophyllopsida , relatives of the bear moss plants . The only species is Tarella trowenii .
features
The main axes branch out isotomically, stand in one plane (planar) and are curled up (circinat) at the tip. You are naked. The smaller side branches are smooth, circinate and also branched. They are arranged irregularly on the main axes. Anatomical features are not known.
The sporangia are kidney-shaped and open with similar flaps (isovalvat). They stand on short stems in two opposite rows in an indistinct, branched fertile zone of the shoot. In contrast to most other zosterophyllopsida , the sporangia are auricular, i.e. ear-shaped with their longitudinal axis in the longitudinal direction of the stem axis that supports them. The spores are spherical to almost tetrahedral, condensed at the equator and have a diameter of 31 to 43 µm. A triple scar was not observed.
The gametophyte is unknown.
distribution
Tarella trowenii is known from numerous but fragmentary finds from the Senni Beds of South Wales. The strata are dated to the early Devonian ( Pragian ).
Systematics
The genus Tarella was placed by Kenrick and Crane after cladistic studies together with Gosslingia and Oricilla in a separate family Gosslingiaceae, which is characterized by the ear-shaped sporangia.
supporting documents
- Paul Kenrick, Peter R. Crane: The Origin and Early Diversification of Land Plants. A Cladistic Study . Smithsonian Institution Press, Washington DC 1997, v. a. P. 335. ISBN 1-56098-729-4
- Thomas N. Taylor, Edith L. Taylor: The Biology and Evolution of Fossil Plants . Prentice Hall, Englewood Cliffs 1993, p. 211. ISBN 0-13-651589-4