Stromatolites or stromatoliths are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota. These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral "microbial mats". In turn, these mats build up layer by layer, growing gradually over time. A stromatolite may grow to a meter or more. Fossilized stromatolites provide important records of some of the most ancient life. Today the living forms are rare.
Cyanobacteria, also called Cyanobacteriota or Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name cyanobacteria refers to their color, which similarly forms the basis of cyanobacteria's common name, blue-green algae, although they are not usually scientifically classified as algae. They appear to have originated in a freshwater or terrestrial environment. Sericytochromatia, the proposed name of the paraphyletic and most basal group, is the ancestor of both the non-photosynthetic group Melainabacteria and the photosynthetic cyanobacteria, also called Oxyphotobacteria.
Receptaculites is the name-bearing genus for an extinct group of conspicuous benthic marine genera, the receptaculitids, that lived from the Early Ordovician through the Permian period, peaking in the Middle Ordovician. The group's phylogenetic origin has long been obscure, with some arguing that they were calcareous algae, probably of the order Dasycladales. Receptaculitids lived in warm, shallow seas, but consensus disagreeing. They have been described from all continents except Antarctica. In some areas they were important reef-formers, and they also occur as isolated specimens.
Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by cyanobacterial growth. Oncolites are very similar to stromatolites, but, instead of forming columns, they form approximately spherical structures. The oncoids often form around a central nucleus, such as a shell fragment, and a calcium carbonate structure is deposited by encrusting microbes. Oncolites are indicators of warm waters in the photic zone, but are also known in contemporary freshwater environments. These structures rarely exceed 10 cm in diameter.
Thrombolites are clotted accretionary structures formed in shallow water by the trapping, binding, and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.
Girvanella is a fossil thought to represent the calcified sheath of a filamentous cyanobacterium known from the Burgess Shale and other Cambrian fossil deposits.
Archaeopriapulida is a group of priapulid worms known from Cambrian lagerstätte. The group is closely related to, and very similar to, the modern Priapulids. It is unclear whether it is mono- or polyphyletic. Despite a remarkable morphological similarity to their modern cousins, they fall outside of the priapulid crown group, which is not unambiguously represented in the fossil record until the Carboniferous. In addition to well-preserved body fossils, remains of several archaeopriapulid taxa are known to have been preserved primarily as organic microfossils, such as isolated scalids and pharyngeal teeth. They are probably closely related or paraphyletic to the palaeoscolecids; the relationship between these basal worms is somewhat unresolved.
Rothpletzella is a genus of calcimicrobe known from the Silurian of Gotland, the Devonian of France, as well as the Ordovician of China. It has been hypothesised to be a cyanobacterium, and shares morphological similarities with extant cyanobacteria. The genus is named in honor of August Rothpletz.
Wetheredella is a genus of calcimicrobes initially described from the Silurian of England, and subsequently reported from the Upper Ordovician to the end of the Carboniferous periods; its reefs are stated as being characteristic of the Ordovician-Silurian periods. Its taxonomic position is uncertain; it has been suggested to be a foraminiferan, a cyanobacterium or simply treated as a microproblematicum; Vachard & Cózar (2010) refer it to the Algospongia, a similarly controversial group that they assigned to the Protista but later, per Vachard, 2021, to Algae incertae sedis, in its own family and suborder (Wetheredellina) in the order Moravamminida. The genus is named in honor of the geologist Edward Wethered.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2014.
The Laborcita Formation is a geologic formation in the Sacramento Mountains of New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2015.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2016.
Sphaerocodium is a fossil that represents the remains of bacteria in the phylum Cyanobacteria, often called blue-green algae.
Proaulopora is a Cambrian–Ordovician fossil genus of calcareous algae. It has been variously thought to belong to the green algae, red algae or cyanobacteria. It was originally established by the Russian paleontologist Aleksandr Grigoryevich Vologdin in 1937, for species known from the Lower Cambrian of the western Altai Mountains.
This article records new taxa of fossil plants that are scheduled to be described during the year 2020, as well as other significant discoveries and events related to paleobotany that are scheduled to occur in the year 2020.
"Porostromata" is an antiquated form taxon that refers to fossil cyanobacteria. The term porostromate is also used as a descriptor of textures and microstructure of stromatolites and oncolites which contain tubules or other cellular structures.
"Spongiostromata" is an antiquated form taxon that refers primarily to fossil cyanobacteria. "Spongiostromate" is also used to describe stromatolites and oncolites that do not preserve clear tubules or other cellular microstructure.
Algospongia is a class of small, calcified fossil organisms of uncertain taxonomic position, assigned in a comprehensive 2010 review to "Animalia" incertae sedis, but both prior to and post that to an unnamed phylum of Algae; other workers simply list them as Problematica. They occur in carbonate rocks of the Paleozoic era and their last representatives occur in the Late Permian geological period. Characteristic genera include Aoujgalia, Moravammina and the early-appearing Wetheredella, although the taxonomic validity of the last named genus has been disputed.
Beresellaceae is an extinct family of organisms of uncertain affinity, sometimes placed within the Metazoa, but tentatively assigned to the green alga order Dasycladales. Beresellids were cosmopolitan and their fossils are found in strata ranging in age from the late Devonian to the early Permian.
