| Palaeoglomus | |
|---|---|
 | |
| Spore and arbuscle of Palaeoglomus strotheri, from Douglas Lake Member of Lenoir Limestone, at Douglas Dam, Tennessee [1] | |
| Scientific classification | |
| Kingdom: | |
| Division: | |
| Class: | |
| Family: | |
| Genus: | Palaeoglomus Redecker et al. (2002) [2] |
| Type species | |
| Palaeoglomus grayi Redecker et al. (2002) | |
Palaeoglomus ("ancient ball") is a genus of microscopic mycorrhizal fossil, found in palynological preparations of rocks which separate out organic remains by acid dissolution.
Palaeoglomus has large spherical to ellipsoidal spores with multilayered walls, as well as irregularly shaped vesicles, attached to aseptate hyphae.
Palaeoglomus grayi type species from the Middle Ordovician Guttenberg Formation near Platteville, Wisconsin. [2]
Palaeoglomus boullardi from the Early Devonian Rhynie Chert bear Rhynie, Scotland. [3]
Palaeoglomus strotheri from the Middle Ordovician (Darriwilian, 460 million years old) Douglas Lake Member of the Lenoir Limestone from Douglas Dam, Tennessee. [1]
Palaeoglomus is similar to modern mycorrhizae such as Glomus .
Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeography), and the evolutionary history of plants, with a bearing upon the evolution of life in general. A synonym is paleophytology. It is a component of paleontology and paleobiology. The prefix palaeo- means "ancient, old", and is derived from the Greek adjective παλαιός, palaios. Paleobotany includes the study of terrestrial plant fossils, as well as the study of prehistoric marine photoautotrophs, such as photosynthetic algae, seaweeds or kelp. A closely related field is palynology, which is the study of fossilized and extant spores and pollen.
The Rhynie chert is an Early Devonian sedimentary deposit exhibiting extraordinary fossil detail or completeness. It is exposed near the village of Rhynie, Aberdeenshire, Scotland; a second unit, the Windyfield chert, is located some 700 m away. The Rhynie chert contains exceptionally preserved plant, fungus, lichen and animal material preserved in place by an overlying volcanic deposit. The bulk of the fossil bed consists of primitive plants, along with arthropods, lichens, algae and fungi.
The Givetian is one of two faunal stages in the Middle Devonian period. It lasted from 387.7 million years ago to 382.7 million years ago. It was preceded by the Eifelian stage and followed by the Frasnian stage. It is named after the town of Givet in France. The oldest forests occurred during the late Givetian. The lower GSSP is located at Jebel Mech Irdane, Tafilalt, Morocco.
Asteroxylon is an extinct genus of vascular plants of the Division Lycopodiophyta known from anatomically preserved specimens described from the famous Early Devonian Rhynie chert and Windyfield chert in Aberdeenshire, Scotland. Asteroxylon is considered the most basal member of the Lycopsida.
The rhyniophytes are a group of extinct early vascular plants that are considered to be similar to the genus Rhynia, found in the Early Devonian. Sources vary in the name and rank used for this group, some treating it as the class Rhyniopsida, others as the subdivision Rhyniophytina or the division Rhyniophyta. The first definition of the group, under the name Rhyniophytina, was by Banks, since when there have been many redefinitions, including by Banks himself. "As a result, the Rhyniophytina have slowly dissolved into a heterogeneous collection of plants ... the group contains only one species on which all authors agree: the type species Rhynia gwynne-vaughanii". When defined very broadly, the group consists of plants with dichotomously branched, naked aerial axes ("stems") with terminal spore-bearing structures (sporangia). The rhyniophytes are considered to be stem group tracheophytes.
Prototaxites is a genus of terrestrial fossil fungi dating from the Middle Ordovician until the Late Devonian periods, approximately 470 to 360 million years ago. Prototaxites formed small to large trunk-like structures up to 1 metre (3 ft) wide, reaching 8 metres (26 ft) in height, made up of interwoven tubes around 50 micrometres (0.0020 in) in diameter, making it by far the largest land-dwelling organism of its time.
The evolution of plants has resulted in a wide range of complexity, from the earliest algal mats, through multicellular marine and freshwater green algae, terrestrial bryophytes, lycopods and ferns, to the complex gymnosperms and angiosperms of today. While many of the earliest groups continue to thrive, as exemplified by red and green algae in marine environments, more recently derived groups have displaced previously ecologically dominant ones; for example, the ascendance of flowering plants over gymnosperms in terrestrial environments.
Polysporangiophytes, also called polysporangiates or formally Polysporangiophyta, are plants in which the spore-bearing generation (sporophyte) has branching stems (axes) that bear sporangia. The name literally means many sporangia plant. The clade includes all land plants (embryophytes) except for the bryophytes whose sporophytes are normally unbranched, even if a few exceptional cases occur. While the definition is independent of the presence of vascular tissue, all living polysporangiophytes also have vascular tissue, i.e., are vascular plants or tracheophytes. Extinct polysporangiophytes are known that have no vascular tissue, and so are not tracheophytes.
Aglaophyton major was the sporophyte generation of a diplohaplontic, pre-vascular, axial, free-sporing land plant of the Lower Devonian. It had anatomical features intermediate between those of the bryophytes and vascular plants or tracheophytes.
Rhynia is a single-species genus of Devonian vascular plants. Rhynia gwynne-vaughanii was the sporophyte generation of a vascular, axial, free-sporing diplohaplontic embryophytic land plant of the Lower Devonian that had anatomical features more advanced than those of the bryophytes. Rhynia gwynne-vaughanii was a member of a sister group to all other eutracheophytes, including modern vascular plants.
Horneophyton is an extinct early plant which may form a "missing link" between the hornworts and the Rhyniopsida. It is a member of the class Horneophytopsida. Horneophyton is among the most abundant fossil organisms found in the Rhynie chert, a Devonian Lagerstätte in Aberdeenshire, UK. A single species, Horneophyton lignieri, is known. Its probable female gametophyte is the form taxon Langiophyton mackiei.
The evolution of fungi has been going on since fungi diverged from other life around 1.5 billion years ago, with the glomaleans branching from the "higher fungi" at ~570 million years ago, according to DNA analysis. Fungi probably colonized the land during the Cambrian, over 500 million years ago,, and possibly 635 million years ago during the Ediacaran, but terrestrial fossils only become uncontroversial and common during the Devonian, 400 million years ago.
Ventarura is a genus of extinct vascular plants of the Early Devonian. Fossils were found in the Windyfield chert, Rhynie, Scotland. Some features, such as bivalved sporangia borne laterally and the anatomy of the xylem, relate this genus to the zosterophylls. Other features are unclear due to poor preservation.
![Douglas Lake Member Geologic formation in [[Tennessee]], United States](https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Casterlorum_crispum_slab.jpg/313px-Casterlorum_crispum_slab.jpg)
The Douglas Lake Member is a geologic unit of member rank of the Lenoir Limestone that overlies the Mascot Dolomite and underlies typical nodular member of the Lenoir Limestone in Douglas Lake, Tennessee, region. It fills depressions that are part of a regional unconformity at the base of Middle Ordovician strata, locally the Lenoir Limestone, that separates them from the underlying Lower Ordovician strata, locally the Knox Group.
Casterlorum is a genus of hornwort fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee The genus was named in honor of Ken Caster.
Cestites ("girdle") was at first considered a ctenophore, but now is regarded as genus of liverwort fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee.
Janegraya is a genus of liverwort fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee. The generic name honors Jane Gray,and the epithet means 'prophetess".
Dollyphyton is a genus of moss fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee. The generic name honors Dolly Parton whose Dollywood resort is nearby. The epithet honors Art Boucot.
Edwardsiphyton is a genus of moss fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee The genus was named in honor of Dianne Edwards, and the epithet refers to the shape of the capsules.
Douglasocaris is a genus of Notostraca fossil from the Middle Ordovician Douglas Lake Member of the Lenoir Limestone from Douglas Dam Tennessee.