Peytoia infercambriensis Temporal range: | |
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Interpretive drawing of holotype specimen of P. infercambriensis | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | † Dinocaridida |
Order: | † Radiodonta |
Family: | † Hurdiidae |
Genus: | † Peytoia |
Species: | †P. infercambriensis |
Binomial name | |
†Peytoia infercambriensis (Lendzion, 1975) | |
Synonyms | |
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Peytoia infercambriensis is a species of hurdiid radiodont in the genus Peytoia .
P. infercambriensis is the geologically oldest known radiodont; its remains date to the third age of the Cambrian. The type and only known specimen, a partial appendage, was found in a core sample from a borehole nearly five kilometers deep in northern Poland. P. infercambriensis was previously regarded as belonging to a separate genus, Cassubia, named after the historical region of Kashubia in which the specimen was found, but Cassubia is now considered a junior synonym of Peytoia.
The holotype—and only—specimen was recovered from the Kościerzyna borehole, in the Cambrian Stage 3 aged Zawiszyn Formation. It was found in the Fallotaspis Zone making it older than the Chengjiang biota. It was described by Kazimiera Lendzion in 1975 and given the name Pomerania infercambriensis, in reference to its Lower Cambrian provenance and the Pomerania region in which the specimen was found. [1] In her initial description, Lendzion interpreted the fossil as preserving 11 thoracic segments and a chelicera of a Leanchoilia -like arthropod. [1] In 1977, Lendzion discovered that the name Pomerania had already been used by an ammonoid, so she renamed the genus Cassubia, after the Kaszuby region of where the specimen was found. [2]
In 1988, Jerzy Dzik and Kazimiera Lendzion reinterpreted the specimen as representing the appendage of an anomalocaridid. They interpreted both the "thorax" and "chelicera" as both parts of a single elongate appendage, similar to that of Anomalocaris . [3] Some researchers, such as Simon Conway Morris, suggested that it may even be synonymous with Anomalocaris itself. [4] In 1995, E. L. Bousfield proposed a taxonomic arrangement of early arthropods in which Cassubia and Anomalocaris were assigned to the same class, Anomalocaridea, but Cassubia was given a subclass of its own, Cassubiata. Though recognizing Cassubia as related to Anomalocaris, Bousfield followed Lendzion's original interpretation of the specimen as comprising a short appendage and long body. [5] When the radiodont Tamisiocaris was discovered by Allison Daley and John Peel in 2010, they took note of its apparent similarity to Cassubia infercambriensis, as it had been interpreted by Dzik and Lendzion. [6] In 2012, Joachim Haug et al. interpreted Cassubia as similar to the megacheiran Occacaris . [7]
These diverse interpretations led Alison Daley and David Legg to restudy the original specimen. They concluded that the specimen did indeed consist of both a body and appendage, but that they did not belong to the same animal. Rather, the body was that of an indeterminate arthropod, while the appendage was that of a radiodont similar to Peytoia nathorsti. As such, they synonymized Cassubia with Peytoia, making the new combination Peytoia infercambriensis. [8]
Peytoia infercambriensis differed from its close relative Peytoia nathorsti in several characteristics of its frontal appendage, the only part of its anatomy known. The ventral spines are only half as wide as the associated podomere, and are estimated to have borne approximately 24 tightly-spaced auxiliary spines. The endites decrease sharply in length, such that the distalmost endite is only a quarter the length of the proximalmost. [8]
The Zawiszyn Formation, in which the only known specimen of Peytoia infercambriensis was found, dates back to the third age of the Cambrian, making P. infercambriensis the oldest known radiodont. [8] P. infercambriensis predates the earliest known mineralized trilobites from Poland, but the trilobite-like nektaspid Liwia is known from close to the same layer as P. infercambriensis. The enigmatic small shelly fossil Mobergella is abundant in the rock layers where Liwia and P. infercambriensis are found. [3] The depositional environment was a shallower-water environment than typical of places with Burgess Shale-type preservation. [4]
Opabinia regalis is an extinct, stem group arthropod found in the Middle Cambrian Burgess Shale Lagerstätte of British Columbia. Opabinia was a soft-bodied animal, measuring up to 7 cm in body length, and its segmented trunk had flaps along the sides and a fan-shaped tail. The head shows unusual features: five eyes, a mouth under the head and facing backwards, and a clawed proboscis that probably passed food to the mouth. Opabinia probably lived on the seafloor, using the proboscis to seek out small, soft food. Fewer than twenty good specimens have been described; 3 specimens of Opabinia are known from the Greater Phyllopod bed, where they constitute less than 0.1% of the community.
Anomalocaris is an extinct genus of radiodont, an order of early-diverging stem-group arthropods.
Peytoia is a genus of hurdiid radiodont, an early diverging order of stem-group arthropods, that lived in the Cambrian period, containing two species, Peytoia nathorsti from the Miaolingian of Canada and Peytoia infercambriensis from Poland, dating to Cambrian Stage 3. Its two frontal appendages had long bristle-like spines, it had no fan tail, and its short stalked eyes were behind its large head.
Amplectobelua is an extinct genus of late Early Cambrian amplectobeluid radiodont, a group of stem arthropods that mostly lived as free-swimming predators during the first half of the Paleozoic Era.
Anomalocarididae is an extinct family of Cambrian radiodonts, a group of stem-group arthropods.
Parapeytoia is a genus of Cambrian arthropod. The type and only described species is Parapeytoia yunnanensis, lived over 518 million years ago in the Maotianshan shales of Yunnan, China. Unidentified fossils from the same genus also had been discovered from the nearby Wulongqing Formation.
Megacheira is an extinct class of predatory arthropods defined by their possession of spined "great appendages". Their taxonomic position is controversial, with studies either considering them stem-group euarthropods, or stem-group chelicerates. The homology of the great appendages to the cephalic appendages of other arthropods is also controversial. Uncontested members of the group were present in marine environments worldwide from the lower to middle Cambrian.
Schinderhannes bartelsi is a species of hurdiid radiodont (anomalocaridid) known from one specimen from the lower Devonian Hunsrück Slates. Its discovery was astonishing because previously, radiodonts were known only from exceptionally well-preserved fossil beds (Lagerstätten) from the Cambrian, 100 million years earlier.
Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. They may be referred to as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the last two originally refer to the family Anomalocarididae, which previously included all species of this order but is now restricted to only a few species. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and used for a variety of functions. Radiodonts included the earliest large predators known, 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 gainessii, Cambroraster falcatus and Amplectobelua symbrachiata, the Ordovician Aegirocassis benmoulai and the Devonian Schinderhannes bartelsi.
Hurdia is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. Fossils have been found in North America, China and the Czech Republic.
Stanleycaris is an extinct, monotypic genus of hurdiid radiodont from the middle Cambrian (Miaolingian). The type species is Stanleycaris hirpex. Stanleycaris was described from the Stephen Formation near the Stanley Glacier and Burgess Shale locality of Canada, as well as Wheeler Formation of United States. The genus was characterized by the rake-like frontal appendages with robust inner spines.
Liwia is a genus of nektaspid It includes the following species, both are known from borehole samples several kilometers in depth from the Zawiszyn Formation in Poland, which has also yielded Peytoia infercambriensis.
Cucumericrus ("cucumber-leg") is an extinct genus of stem-arthropod. The type and only species is Cucumericrus decoratus, with fossils discovered from the Maotianshan Shales of Yunnan, China.
Caryosyntrips ("nutcracker") is an extinct genus of stem-arthropod which known from Canada, United States and Spain during the middle Cambrian.
Aegirocassis is an extinct genus of giant radiodont arthropod belonging to the family Hurdiidae that lived 480 million years ago during the early Ordovician in the Fezouata Formation of Morocco. It is known by a single species, Aegirocassis benmoulai. Van Roy initiated scientific study of the fossil, the earliest known of a "giant" filter-feeder discovered to date. Aegirocassis is considered to have evolved from early predatory radiodonts. This animal is characterized by its long, forward facing head sclerite, and the endites on its frontal appendages that bore copious amounts of baleen-like auxiliary spines. This animal evolving filter-feeding traits was most likely a result of the Great Ordovician Biodiversification Event, when environmental changes caused a diversification of plankton, which in turn allowed for the evolution of new suspension feeding lifeforms. Alongside the closely related Pseudoangustidontus, an unnamed hurdiid from Wales, the middle Ordovician dinocaridid Mieridduryn, and the Devonian hurdiid Schinderhannes this radiodont is one of the few known dinocaridids known from post-Cambrian rocks.
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.
Titanokorys is a genus of extinct hurdiid radiodont that existed during the mid Cambrian. It is the largest member of its family from the Cambrian, with a body length of 50 cm (20 in) long, making it one of the largest animals of the time. It bears a resemblance to the related genus Cambroraster. Fossils of T. gainesi were first found within Marble Canyon in 2018. The fossils were not named until 2021 because they were assumed to be giant specimens of Cambroraster.
Erratus is an extinct genus of marine arthropod from the Cambrian of China. Its type and only species is Erratus sperare. Erratus is likely one of the most basal known arthropods, and its discovery has helped scientists understand the early evolution of arthropod trunk appendages. Some of the stem-arthropods like radiodonts did not have legs, instead they had flap like appendages that helped them swim. Erratus on the other hand had not only flaps but also a set of primitive legs. It also supported the theory that the gills of aquatic arthropods probably evolved into the wings and lungs of terrestrial arthropods later in the Paleozoic.
Laminacaris is a genus of extinct stem-group arthropods (Radiodonta) that lived during the Cambrian period. It is monotypic with a single species Laminacaris chimera, the fossil of which was described from the Chengjiang biota of China in 2018. Around the same time, two specimens that were similar or of the same species were discovered at the Kinzers Formation in Pennsylvania, USA. The first specimens from China were three frontal appendages, without the other body parts.
Cordaticaris is a genus of extinct hurdiid radiodont that lived in what is now northern China during the middle Cambrian period. This animal was described in 2020 based off remains found in the Zhangxia Formation, located in the Shandong Province. It is differentiated from other members of its family by its unique heart-shaped frontal sclerite, and its frontal appendages bearing nine endites and seven more elongated subequal endites. This animal was important as it was the first Miaolingian aged hurdiid known from rock layers outside of laurentia, allowing paleontologists to get a better grasp of this families geographic range in life.
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