| Nilssonia Temporal range: | |
|---|---|
 | |
| Nilssonia polymorpha | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Order: | † Nilssoniales (?) |
| Genus: | † Nilssonia (Brongniart), 1825. |
| Species | |
| |
Nilssonia is a genus of fossil foliage traditionally assigned to the Cycadophyta either in Cycadales or their own order Nilssoniales, though the relationships of this genus with the Cycadales have been put into question on chemical grounds. [1]
The genus was erected by Brongniart [2] under the name Nilsonia based on material from the Hettangian of Scania. The spelling of the name (a dedication to Sven Nilsson) was later corrected to Nilssonia. [3] The diagnosis of the genus, initially based on the pinnate Nilssonia brevis, was later amended to include entire-margined and irregularly segmented species as well as information on the cuticle. [4] [5]
Nilssonia leaves can have entire margins, irregularly dissected margins or clearly divided leaflets. The lamina or the leaflets are attached to the midrib or rachis on the 'upper' (adaxial) side of the leaf, unlike in other similar genera such as Taeniopteris. Parallel veins exit the midrib, with no fusion of veins.
Fossils of Nilssonia are found in Triassic, Jurassic and Cretaceous-aged terrestrial strata of East Asia, Australia, North and South America, and Europe. [6] [7] [8]
The distribution of this genus in the Northern Hemisphere extented to low latitudes in Europe and Asia during the Triassic to Middle Jurassic. During the Late Jurassic, the distribution of Nilssonia contracted to higher latitudes in the Siberian area, where the genus persisted up to the Late Cretaceous. [9]
Glossopteris is the largest and best-known genus of the extinct Permian order of seed plants known as Glossopteridales. The genus Glossopteris refers only to leaves, within a framework of form genera used in paleobotany. Species of Glossopteris were the dominant trees of the middle to high-latitude lowland vegetation across the supercontinent Gondwana during the Permian Period. Glossopteris fossils were critical in recognizing former connections between the various fragments of Gondwana: South America, Africa, India, Australia, New Zealand, and Antarctica.
Bennettitales 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 were amongst the most common seed plants of the Mesozoic, 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.
Palissya is an extinct form genus of female (ovule-bearing) conifer cones, known from the Late Triassic (Rhaetian) to the Early Cretaceous (Aptian). The cone of Palissya is noted for its unusual catkin-like construction: Slender bracts are rigidly attached in a helical pattern around a tall woody core. The adaxial (upper) surface of each bract bears two parallel rows of ovules which are encased in cup-like structures formed by scales. The seeds are thin-walled and were likely only viable for a short period of time, meaning that they were probably adapted to wind dispersal.
Pachypteris is a Mesozoic pteridosperm genus of fossil leaves. It has either been aligned with the peltasperms or the corystosperms.
Agathoxylon is a form genus of fossil wood, including massive tree trunks. Although identified from the late Palaeozoic to the end of the Mesozoic, Agathoxylon is common from the Carboniferous to Triassic. Agathoxylon represents the wood of multiple conifer groups, including both Araucariaceae and Cheirolepidiaceae, with late Paleozoic and Triassic forms possibly representing other conifers or other seed plant groups like "pteridosperms".
Zamites is a genus of sterile foliage known from the Mesozoic of North America, Europe, India and Antarctica through the Eocene of North America. It was erected as a form taxon for leaves that superficially resembled the extant cycad Zamia, however it is now believed to belong to a similar but phylogenetically different group, the cyacadeoids (Bennettitales). The fronds are linear or lanceolate in shape, and pinnately compound, with pinnae with parallel veins and smooth margins, and symmetrical and constricted at the base where they are attached obliquely to the upper surface of the rachis. It has been interpreted as a Bennettitalean plant in the family Williamsoniaceae. It is associated with the ovulate cone Williamsonia and male cone Weltrichia.
This article records new taxa of fossil plants that are scheduled to be described during the year 2015, as well as other significant discoveries and events related to paleobotany that are scheduled to occur in the year 2015.
This article contains papers in paleobotany that were published in 2016.
This article records new taxa of plants that are scheduled to be described during the year 2017, as well as other significant discoveries and events related to paleobotany that are scheduled to occur in the year 2017.
Ctenis is a genus of fossil foliage attributable to the Cycadales, being one of the most common genera of cycad fossil leaves in the Mesozoic.
Pterophyllum is an extinct form genus of leaves known from the Carnian to the Maastrichtian, belonging to the Bennettitales. It contains more than 50 species, and is mainly found in Eurasia and North America.
This article records new taxa of fossil plants that are scheduled to be described during the year 2021, as well as other significant discoveries and events related to paleobotany that are scheduled to occur in the year 2021.
Otozamites is an extinct form genus of leaves belonging to the Bennettitales.
Nilssoniopteris is an extinct form genus of leaves belonging to the Bennettitales. Leaves are slender and often entire-margined (smooth-edged), though some species have dissected leaves with numerous small segments extending down to the rachis of the leaf. Nilssoniopteris-like leaves are distinguished by their syndetocheilic stomata, indicating bennettitalean affinities. Similar "taeniopterid" leaves are placed in the genus Nilssonia if their stomata are instead haplocheilic, or Taeniopteris if the cuticle is not preserved. Leaves of Nilssoniopteris vittata from the Middle Jurassic of England are associated with bisexual Williamsoniella reproductive structures.
Pelourdea is an extinct genus of conifer. Species belonging to the genus lived from the Triassic to the Middle Jurassic and have been found in Europe and North America.
This paleobotany list records new fossil plant taxa that were to be described during the year 2022, as well as notes other significant paleobotany discoveries and events which occurred during 2022.
This paleobotany list records new fossil plant taxa that were to be described during the year 2012, as well as notes other significant paleobotany discoveries and events which occurred during 2012.
Taeniopteris is an extinct form genus of Mesozoic vascular plant leaves, perhaps representing those of cycads, bennettitaleans, or marattialean ferns. The form genus is almost certainly a polyphyletic category for unfertile leaves of a certain shape ("taeniopterids") which cannot be assigned to specific groups due to a lack of information on cuticle or spore structures. The leaves are simple, with a strong central vein (rhachis) and an unbroken margin. The central vein leads to nearly perpendicular lateral veins, which may be slightly divided or undivided. The shape of the leaf is variable, but often elongated and smooth-edged. "Taeniopterid" leaves with bennettitalean-type cuticle are placed in the form genus Nilssoniopteris, while those with cycad-type cuticle are placed within Nilssonia and related genera. Some fertile "taeniopterids" preserve spore packages, and can be assigned to marattialean ferns.
This paleobotany list records new fossil plant taxa that were to be described during the year 2023, as well as notes other significant paleobotany discoveries and events which occurred during 2023.
Komlopteris is an extinct genus of "seed fern" with possible corystosperm affinities. Fossils have been found across both hemispheres, dating from the latest Triassic to the early Eocene (Ypresian), making it the youngest "seed fern" in the fossil record.
