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Erdtmanithecales
Erdtmanithecales is an extinct order of gymnosperm plants known from the Mesozoic era. Known remains include pollen organs, seed cones and seeds associated with '' Eucommiidites'' pollen, which is considered diagnostic for the order. The order was first described in 1996. While ''Eucommiidites'' pollen first appears in the Early Jurassic, associated floral remains are not found until the Early Cretaceous. It is thought that the group are closely related to Gnetales as well as possibly Bennettitales. Systematics * Order Erdtmanithecales Friis and Pedersen 1996 **family Erdtrnanithecaeae Friis and Pedersen 1996 ***'' Erdtmanitheca'' Pedersen, Crane & Friis, 1989 (pollen organ) ****''Erdtmanitheca portucalensis'' Mendes et al., 2010 (Aptian-Albian), Lusitanian Basin, Portugal ****''Erdtmanitheca texensis'' Pedersen, Crane & Friis, 1989 Woodbine Formation, Texas, USA, Cenomanian ***'' Erdtmanispermum'' Pedersen, Crane & Friis, 1989 (seeds) ****''Erdtmanispermum juncalense'' Mendes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosperm
The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, ''Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμνόσπερμος ( el, γυμνός, translit=gymnos, lit=naked, label=none and el, σπέρμα, translit=sperma, lit=seed, label=none), literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in yew, ''Torreya'', ''Ginkgo''. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnetophyta
Gnetophyta () is a division of plants (alternatively considered the subclass Gnetidae or order Gnetales), grouped within the gymnosperms (which also includes conifers, cycads, and ginkgos), that consists of some 70 species across the three relict genera: ''Gnetum'' (family Gnetaceae), ''Welwitschia'' (family Welwitschiaceae), and ''Ephedra'' (family Ephedraceae). Fossilized pollen attributed to a close relative of ''Ephedra'' has been dated as far back as the Early Cretaceous. Though diverse in the Early Cretaceous, only three families, each containing a single genus, are still alive today. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of conduits that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question. Thou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bennettitales
Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales are among the most common Mesozoic seed plants, and had morphologies including shrub and cycad-like forms. The foliage of bennettitaleans is superficially nearly indistinguishable from that of cycads, but they are distinguished from cycads by their more complex flower-like reproductive organs, at least some of which were likely pollinated by insects. Although certainly gymnosperms (cone-bearing seed plants), the relationships of bennettitaleans to other seed plants is debated. Their general resemblance to cycads is contradicted by numerous more subtle features of their reproductive systems and leaf structure. Some authors have linked bennettitaleans to angiosperms (flowering plants) and gnetophytes (a rare and unusual group of modern gymnosperms), forming a broader group known as Anth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucommiidites
''Eucommiidites'' is an angiosperm look-alike pollen type from the Mesozoic Era. When it was first described in Sweden, it was thought to represent pollen from the earliest angiosperms. However, it was subsequently shown, due to morphology, that it could not be angiospermous. Later, ''Eucommidites'' pollen was discovered in the pollen chambers of fossil gymnosperm seeds. It was later shown to be the pollen of the extinct gymnosperm order Erdtmanithecales, suggested to have close affinities with Bennettitales and Gnetales. ''Eucommidites'' is tricolpate, which is why it was originally thought to be angiospermous. However, the three colpi are not equal in length, and the exine of the pollen grain is similar to a gymnosperm. ''Eucommidites'' is important in biostratigraphy, and it ranges from the Triassic to the Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Plant Orders
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crato Formation
The Crato Formation is a geologic formation of Early Cretaceous ( Aptian) age in northeastern Brazil's Araripe Basin. It is an important Lagerstätte (undisturbed fossil accumulation) for palaeontologists. The strata were laid down mostly during the Aptian age, about 113 million years ago. It thought to have been deposited in a semi-arid lacustrine wetland environment.Ribeiro et al., 2021 The Crato Formation earns the designation of Lagerstätte due to an exceedingly well preserved and diverse fossil faunal assemblage. Some 25 species of fossil fishes are often found with stomach contents preserved, enabling paleontologists to study predator-prey relationships in this ecosystem. There are also fine examples of pterosaurs, reptiles and amphibians, invertebrates (particularly insects), and plants. Even dinosaurs are represented: a new maniraptor was described in 1996. The unusual taphonomy of the site resulted in limestone accretions that formed nodules around dead organisms, pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incertae Sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by ' (of uncertain family), ' (of uncertain suborder), ' (of uncertain order) and similar terms. Examples *The fossil plant '' Paradinandra suecica'' could not be assigned to any family, but was placed ''incertae sedis'' within the order Ericales when described in 2001. * The fossil ''Gluteus minimus'', described in 1975, could not be assigned to any known animal phylum. The genus is therefore ''incertae sedis'' within the kingdom Animalia. * While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves ''incertae sedis''. It was later agreed to place them in a separate order, Cathartiformes. * Bocage's longbill, ''Motacilla bocagii' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jydegaard Formation
The Jydegaard Formation (also spelled as 'Jydegård') is a geological formation dating to the Early Cretaceous, about 145-139 million years ago. It is on the island of Bornholm, Denmark. Vertebrate fossils have been found in the formation. Fossil content Thin bone fragments have been uncovered that may belong to pterosaurs or birds. Dinosaurs A tooth possibly belonging to a juvenile titanosaur has been found in the formation. Crocodylomorphs Fish Fish remains have been found in coprolites possibly belonging to the dromaeosaur ''Dromaeosauroides'' or marine turtles. Also, unidentified pycnodont jaws and two small stem- teleosteans have been uncovered. Amioid scales have also been revealed. Turtles Unidentified turtle carapaces have been uncovered in the Formation. Lizards A lower jaw from a lizard has been recovered from the formation. Bivalves See also * List of fossiliferous stratigraphic units in Denmark See also * Lists of fossiliferous str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
