Leanchoilia Temporal range: | |
---|---|
Leanchoilia superlata | |
Reconstruction of Leanchoilia superlata | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | † Megacheira |
Order: | † Leanchoilida Størmer, 1944 |
Family: | † Leanchoiliidae Raymond, 1935 |
Genus: | † Leanchoilia Walcott, 1912 |
Type species | |
†Leanchoilia superlata Walcott, 1912 | |
Other species | |
(but see text) | |
Synonyms | |
Synonyms of Leanchoilia
Synonyms of L. superlata
Synonyms of L. illecebrosa
|
Leanchoilia is a megacheiran arthropod known from Cambrian deposits of the Burgess Shale in Canada and the Chengjiang biota of China. [1]
L. superlata was about 5 centimetres (2.0 in) long and had long, whip-like flagellae extending from its great appendages. Its internal organs are occasionally preserved within the substrate in three dimensions. [2] [3] Their two pairs of eyes are protected and covered by their exterior head shields, with two eyes being located on each side. [4] [5]
Seven species are tentatively accepted today: L. superlata (the type species), L. persephone and L. protogonia from the Burgess Shale, L. illecebrosa and L. obesa from the Chengjiang biota, ''L. robisoni from Kaili, and L.? hanceyi from the Spence Shale. L. superlata and L. persephone may however be examples of sexual dimorphism. [6] [7] [8]
55 specimens of Leanchoilia are known from the Greater Phyllopod bed, where they comprise 0.1% of the community. [9]
Lobopodians are members of the informal group Lobopodia, or the formally erected phylum Lobopoda Cavalier-Smith (1998). They are panarthropods with stubby legs called lobopods, a term which may also be used as a common name of this group as well. While the definition of lobopodians may differ between literatures, it usually refers to a group of soft-bodied, marine worm-like fossil panarthropods such as Aysheaia and Hallucigenia.
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.
Odaraia is a genus of bivalved arthropod from the Middle Cambrian. Its fossils, which reach 15 centimetres (5.9 in) in length, have been found in the Burgess Shale in British Columbia, Canada.
The Burgess Shale of British Columbia is famous for its exceptional preservation of mid-Cambrian organisms. Around 69 other sites have been discovered of a similar age, with soft tissues preserved in a similar, though not identical, fashion. Additional sites with a similar form of preservation are known from the Ediacaran and Ordovician periods.
A number of assemblages bear fossil assemblages similar in character to that of the Burgess Shale. While many are also preserved in a similar fashion to the Burgess Shale, the term "Burgess Shale-type fauna" covers assemblages based on taxonomic criteria only.
Alalcomenaeus is one of the most widespread and longest-surviving arthropod genera of the Early and Middle Cambrian. Known from over 300 specimens in the Burgess Shale and the Chengjiang biota. It is a member of the family Leanchoiliidae in the group Megacheira.
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.
Clypecaris is genus of bivalved Cambrian arthropod known from the Chengjiang biota of Yunnan, China. The genus was initially described for the type species C. pteroidea by Hou, 1999. A second species C. serrata was described by Yang et al. in 2016. The species are primarily distinguished by the presence of a serrated edge on the front of the carapace of C. serrata. C. serrata is noted for the modification of an anterior pair of limbs into spined grasping appendages, indicating a predatory lifestyle. It is unknown whether a similar structure was present in C. pteroidea.Clypecaris is considered to likely be a member or a close relative of Hymenocarina, and is closely related to Perspicaris. As well as to Ercaicunia.
Haikoucaris is a genus of megacheiran arthropod that contains the single species Haikoucaris ercaiensis. It was discovered in the Cambrian Chengjiang biota of China.
Isoxys is a genus of extinct bivalved Cambrian arthropod; the various species of which are thought to have been freely swimming predators. It had a pair of large spherical eyes, and two large frontal appendages used to grasp prey.
Pectocaris is an extinct genus of bivalved arthropods from the Cambrian Maotianshan Shales, Yunnan Province of China. There are currently four known species within the genus.
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.
Miraluolishania is an extinct lobopodian known from Chengjiang County in China. It is remarkable for the possession of lensed pit-eyes. The only species, Miraluolishania haikouensis, was described from the Maotianshan Shales at Haikou by Jianni Liu and Degan Shu in 2004. In 2009, a team of palaeontologists at the Yunnan University, led by Xiaoya Ma reported the discovery of 42 other specimens from Haikou. With the help of Swiss palaeontologist Jan Bergström, Ma and Hou came to the conclusion that all the specimens were the same species as Luolishania; another lobopod discovered from the Chengjian in 1989. Chengjian is 40 kms from Haikou and the fossil fauna are different. A reassessment by Liu and Shu's team at the Northwest University in 2008 established that Luolishania and Miraluolishania are distinct animals.
Vetulicola cuneata is a species of extinct animal from the Early Cambrian Chengjiang biota of China. It was described by Hou Xian-guang in 1987 from the Lower Cambrian Chiungchussu Formation, and became the first animal under an eponymous phylum Vetulicolia.
The Artiopoda is a grouping of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomorpha. Trilobites, in part due to abundance of findings owing to their mineralized exoskeletons, are by far the best recorded, diverse, and long lived members of the clade. Other members, which lack mineralised exoskeletons, are known mostly from Cambrian deposits.
Kylinxia is a genus of extinct arthropod described in 2020. It was described from six specimens discovered in Yu'anshan Formation in southern China. The specimens are assigned to one species Kylinxia zhangi. Dated to 518 million years, the fossils falls under the Cambrian period. Announcing the discovery on 4 November 2020 at a press conference, Zeng Han of the Nanjing Institute of Geology and Paleontology, said that the animal "bridges the evolutionary gap from Anomalocaris to true arthropods and forms a key ‘missing link’ in the origin of arthropods," which was "predicted by Darwin’s evolutionary theory." The same day the formal description was published in Nature.
Luolishania is an extinct genus of lobopodian panarthropod and known from the Lower Cambrian Chiungchussu Formation of the Chengjiang County, Yunnan Province, China. A monotypic genus, it contains one species Luolishania longicruris. It was discovered and described by Hou Xian-Guang and Chen Jun-Yuan in 1989. It is one of the superarmoured Cambrian lobopodians suspected to be either an intermediate form in the origin of velvet worms (Onychophora) or basal to at least Tardigrada and Arthropoda. It is the basis of the family name Luolishaniidae, which also include other related lobopods such as Acinocricus, Collinsium, Facivermis, and Ovatiovermis. Along with Microdictyon, it is the first lobopodian fossil discovered from China.
Lenisambulatrix is a genus of extinct worm belonging to the group Lobopodia and known from the Lower Cambrian Maotianshan shale of China. It is represented by a single species L. humboldti. The incomplete fossil was discovered and described by Qiang Ou and Georg Mayer in 2018. Due to its missing parts, its relationship with other lobopodians is not clear. It shares many structural features with another Cambrian lobopodian Diania cactiformis, a fossil of which was found alongside it.
Oestokerkus is an extinct genus of Cambrian megacheiran arthropod known from the Emu Bay Shale of Kangaroo Island, Australia. It belongs to the family Leanchoiliidae. It had a large head shield that was more than a third of the trunk's length, as well as a large pair of eyes. The great appendages have long flagellae projecting from them. The head shield probably had two pairs of cephalic appendages. The trunk has 11 segments. The exopods of the biramous limbs are fringed with long setae. The body ended with a telson, which was probably dorsally flattened.