Paropsonema Temporal range: | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Stem group: | Ambulacraria |
Clade: | † Cambroernida |
Class: | † Eldonioidea |
Clade: | † Paropsonemida |
Genus: | † Paropsonema Clarke 1900 |
Type species | |
†P. cryptophya Clarke 1900 | |
Species [1] [2] | |
|
Paropsonema is an eldonioid known from the Devonian of upstate New York and (if P. mirabile is a species of Paropsonema rather than Discophyllum ) the Silurian of southern Australia. It is the latest-surviving known member of the Eldonioidea and Cambroernida. [1]
A specimen described in 2018 may represent an additional species, but has been tentatively assigned to P. cryptohya; [3] it represents the youngest described paropsonemid. [4]
The species Discophyllum mirabile has been thought to be closer to Paropsonema than to the sole previously-described species of Discophyllum, D. peltata. [5] As a result, sources treat it as Paropsonema mirabile. [1] Conversely, at least one worker has treated P. cryptophya as a member of Discophyllum, D. cryptophya, although this has not been followed by later authors. [6] Regardless, Paropsonema and Discophyllum are grouped together informally as "paropsonemids." [6] [1]
Vetulicolia is a group of bilaterian marine animals encompassing several extinct species from the Cambrian, and possibly Ediacaran, periods. As of 2023, the majority of workers favor placing Vetulicolians in the stem group of the Chordata, but some continue to favor a more crownward placement as a sister group to the Tunicata. It was initially erected as a monophyletic clade with the rank of phylum in 2001, with subsequent work supporting its monophyly. However, more recent research suggests that vetulicolians may be paraphyletic and form a basal evolutionary grade of stem chordates.
The Maotianshan Shales (帽天山页岩) are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation, famous for their Konservat Lagerstätten, deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales form one of some forty Cambrian fossil locations worldwide exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of the Burgess Shale of British Columbia, Canada. They take their name from Maotianshan Hill in Chengjiang County, Yunnan Province, China.
The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte. It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale is dated as Cambrian Series 2, Stage 4, correlated with the upper Botomian Stage of the Lower Cambrian.
Vetulicola is an extinct genus of marine animal discovered from the Cambrian of China. It is the eponymous member of the enigmatic phylum Vetulicolia, which is of uncertain affinities but may belong to the deuterostomes. The name was derived from Vetulicola cuneata, the first species described by Hou Xian-guang in 1987 from the Lower Cambrian Chiungchussu Formation in Chengjiang, China.
Anomalocarididae is an extinct family of Cambrian radiodonts, a group of stem-group arthropods.
Dinomischusis an extinct genus of stalked filter-feeding animals within the Cambrian period, with specimens known from the Burgess Shale and the Maotianshan Shales. While long of uncertain affinities, recent studies have suggested it to be a stem-group ctenophore.
Misszhouia is a genus of small to average sized marine trilobite-like arthropods within the Naraoiidae family, that lived during the early Cambrian period. The species are M. longicaudata, from the Maotianshan Shales, described in 1985, and M. canadensis, from the Burgess Shale and described in 2018, although later species may belongs to genus Naraoia instead.
Schinderhannes bartelsi is a species of hurdiid radiodont (anomalocaridid), known from one specimen from the Lower Devonian Hunsrück Slates. Its discovery was astonishing because the latest definitive radiodonts were known only from the Early Ordovician, at least 66 million years earlier than this taxon.
Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and were used for a variety of functions. Radiodonts were among the earliest large predators, but they also included sediment sifters and filter feeders. Some of the most famous species of radiodonts are the Cambrian taxa Anomalocaris canadensis, Hurdia victoria, Peytoia nathorsti, Titanokorys gainesi, Cambroraster falcatus and Amplectobelua symbrachiata. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member Schinderhannes bartelsi from Germany.
The palaeoscolecids are a group of extinct ecdysozoan worms resembling armoured priapulids. They are known from the Lower Cambrian to the lower Ludfordian ; they are mainly found as disarticulated sclerites, but are also preserved in many of the Cambrian lagerstätten. They take their name from the typifying genus Palaeoscolex. Other genera include Cricocosmia from the Lower Cambrian Chengjiang biota. Their taxonomic affinities within Ecdysozoa have been the subject of debate.
Eldonia is an extinct soft-bodied cambroernid best known from the Fossil Ridge outcrops of the Burgess Shale, particularly in the 'Great Eldonia layer' in the Walcott Quarry. In addition to over 550 specimens collected by Walcott, 224 specimens of Eldonia are known from the Greater Phyllopod bed, where they comprise 0.43% of the community. Species also occur in the Chengjiang biota, Siberia, and in Upper Ordovician strata of Morocco.
Eldonioids are an extinct clade of disc-shaped cambroernids, the Eldonioidea, which lived in the early to middle Paleozoic. The terms "eldonioid" and "eldoniid" have been used somewhat informally and interchangeably, but technically refer to members of the class Eldonioidea and the family Eldoniidae, respectively. The lifestyle of eldonioids is still an unresolved question; some authors reconstruct eldonioids as free-floating planktonic predators similar to jellyfish, while others argue that they were passive detritivores, embedded within the seabed for much of their life.
Stellostomites is a discoidal animal known from the Cambrian Chengjiang biota. It is classified with the eldoniids, and considered a junior synonym of Eldonia by some authors.
Rotadiscus is a genus of discoidal animal known from the Cambrian Chengjiang biota and classified with the eldonioids.
Velumbrella is an eldonioid known from the Early to Middle Cambrian of Poland. The fossils depict a scleritosed disk with a U-shaped gut.
The Cambroernida are a clade of unusual Paleozoic animals with coiled bodies and filamentous tentacles. They include a number of early to middle Paleozoic genera noted as "bizarre" or "orphan" taxa, meaning that their affinities with other animals, living or extinct, have long been uncertain. While initially defined as an "informal stem group," later work with better-preserved fossils has strengthened the argument for Cambroernida as a monophyletic clade.
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.
Hurdiidae is an extinct cosmopolitan family of radiodonts, a group of stem-group arthropods, which lived during the Paleozoic Era. It is the most long-lived radiodont clade, lasting from the Cambrian period to the Devonian period.
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 2020.