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Lobopodia
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''. However, other genera like '' Kerygmachela'' and '' Pambdelurion'' (which have features similar to other groups) are often referred to as “gilled lobopodians”. The oldest near-complete fossil lobopodians date to the Lower Cambrian; some are also known from Ordovician, Silurian and Carboniferous Lagerstätten. Some bear toughened claws, plates or spines, which are commonly preserved as carbonaceous or mineralized microfossils in Cambrian strata. The grouping is considered to be paraphyletic, as the three living panarthropod groups (A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropoda
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an exoskeleton with a cuticle made of chitin, often mineralised with calcium carbonate, a body with differentiated ( metameric) segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired ventral nerve cords running through all segments and forming paired ganglia in each segment. Their heads are formed by fusion of varying numbers of segments, and their brains are formed by fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diania
''Diania'' is an extinct genus of lobopodian Panarthropoda, panarthropod found in the Lower Cambrian Maotianshan shale of China, represented by a single species - ''D. cactiformis''. Known during its investigation by the nickname "walking cactus", this organism belongs to a group known as the armoured lobopodians, and has a simple worm-like body with robust, spiny legs. Initially, the legs were thought to have a jointed exoskeleton and ''Diania'' was suggested to be evolutionarily close to early Arthropod, arthropods, but many later studies have rejected this interpretation. Discovery Fossils of ''Diania'' were discovered independently by Jianni Liu from the Northwest University (China) in Xi’an, Qiang Ou from the China University of Geosciences (Beijing), China University of Geosciences in Beijing and Michael Steiner of the Free University Berlin. The fossils come from the famous Chengjiang deposit – or Maotianshan shale – of south-west China and are about 520 million years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panarthropods
Panarthropoda is a clade comprising the greatest diversity of animal groups. It contains the extant phyla Arthropoda (Euarthropoda), Tardigrada (water bears) and Onychophora (velvet worms), although the precise relationships among these remained uncertain according to studies published in 2023 and 2024. Panarthropods also include extinct marine legged worms known as lobopodians ("Lobopodia"), a paraphyletic group where the last common ancestor and basal members (stem-group) of each extant panarthropod phylum are thought to have risen. However the term "Lobopodia" is sometimes expanded to include tardigrades and onychophorans as well. Common characteristics of the Panarthropoda include a segmented body, paired ladder-like ventral nervous system, and the presence of paired appendages correlated with body segments. Taxonomy Not all studies support the monophyly of Panarthropoda, but most do, including neuroanatomical, phylogenomic and palaeontological studies. At least a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microdictyon
is an extinct genus of lobopodian worm characterized by its net-like sclerite armour plates, known from Cambrian deposits around the world. Soft-bodied fossils which preserve more than the sclerites are only known from the Chengjiang Lagerstätte of Yunnan, China. History ''Microdictyon'' sclerite plates have been recovered from around the globe, recovered from rock via acid dissolution which eats away at the rock but leaves behind compositionally distinct microfossils. The first of them were found in the '' Strenuella'' Limestone of Comley, England, in 1975. The genus ''Microdictyon'' was erected by Stefan Bengston, Vladimir Missarzhevsky, and S. C. Matthews in 1981, as an enigmatic net-like microfossil, based on a few isolated plates from South Kazakhstan, although this description lacked a type species and proper description, so a following publication by the same authors in 1986 corrected this. It was unknown at the time what animal could have produced it - suggestio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collinsovermis
''Collinsovermis'' is a genus of extinct panarthropod belonging to the group Lobopodia and known from the middle Cambrian Burgess Shale in British Columbia, Canada. It is monotypic having only one species, ''Collinsovermis monstruosus''. After its initial discovery in 1983, Desmond H. Collins popularised it as a unique animal and was subsequently dubbed "Collins' monster" for its unusual super armoured body. The formal scientific description and name were given in 2020. A similar lobopodian is known from the Emu Bay Shale, however it remains unnamed. Discovery ''Collinsovermis'' was discovered in 1983 by Desmond H. Collins, curator of invertebrate palaeontology at the Royal Ontario Museum, from an expedition at Mount Stephen at the Yoho National Park, British Columbia, Canada. It was found among the Burgess Shale that belonged to the middle Cambrian period called Wuliuan, which is around 509 to 505 million years ago. In 1985, Collins presented the discovery before the Geolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luolishania
''Luolishania'' is an extinct genus of lobopodian panarthropod and known from the Lower Cambrian Chiungchussu Formation (Maotianshan Shales) 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. Discovery A single specimen of ''Luolishania'' fossil was discovered by Hou Xian-guang and Chen Jun-yuan of the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facivermis
''Facivermis'' (meaning "torch worm" ) is a genus of sessile lobopodian from the Lower Cambrian Maotianshan shales of China Anatomy ''Facivermis'' was a worm-like creature up to 90 mm long. Its body was divided into three sections. The anterior section had five equally sized pairs of appendages with two setal rows along the margins. The middle section was elongate and five times longer than the anterior or posterior. The posterior section was pear-shaped and had three rows of hooks surrounding the anus. Classification ''Facivermis'' was considered by its describers to be a polychaete worm. An affinity to the unusual crustacean lineage Pentastomida has also been proposed, but is seen as unlikely. Since its discovery, however, most evidence has supported its being a lobopodian. Liu ''et al.'' draw a comparison to the known lobopodian '' Miraluolishania''. Liu ''et al.'' also note that the pear-shaped end bears a close resemblance to the proboscis of priapulid worms if it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallucishaniids
"Hallucishaniids" are a clade of lobopodians uniting the families Hallucigeniidae and Luolishaniidae. The name of this clade is a portmanteau of its two constituent families. Morphology and description Hallucishaniids have two or three body zones. The first of these contains the eyespot-bearing head and several pairs of feathery appendages likely specialised for filter feeding. The second, larger zone consists of many pairs of clawed limbs used for walking with each pair corresponding to a sclerite, with a third zone present in '' Ovatiovermis'' where the feathery appendages continue with far shorter branches, and clawed limbs are reduced to the last few pairs. The limb claws seem to alternate which direction they face. Most hallucishaniids have spine-like sclerites which vary in width and length, however some like '' Cardiodictyon'' have more plate-like sclerites, and ''Ovatiovermis'' as well as ''Facivermis'' lack them entirely. '' Thanahita'' is especially bizarre, as wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jianshanopodia
''Jianshanopodia ''is a monotypic genus of Cambrian lobopodian, discovered from Maotianshan Shales of Yunnan, China. Description ''Jianshanopodia'' resemble the closely-related siberiid ''Megadictyon''. The head possess a pair of frontal, grasping appendages bear wedge-shaped plates. The pharynx was surrounded by rows of denticles, resembles those of radiodonts and priapulids. The trunk was annulated and possesses a pair of stout legs (lobopods) per body segment. Due to the lack of a complete specimen, the exact number of body segments/leg pair is uncertain. If 12 body segments present, the living animal might grew over 20 cm. Each of the leg was lined up with rows of tubercles and tree-like branches, instead of being tipped with claws as many lobopodians are. The trunk terminated with a large median lobe and a pair of small lateral lobes, forming a fan-like structure. Inside the trunk was a sediment-filled gut surrounded by serially repeated diverticulae. ''Jianshanopo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallucigenia
''Hallucigenia'' is a genus of lobopodian known from Cambrian aged fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual appearance and eccentric history of study; when it was erected as a genus, ''H. sparsa'' was reconstructed as an enigmatic animal upside down and back to front. Lobopodians are a grade of Paleozoic panarthropods from which the velvet worms, water bears, and arthropods arose. Description ''Hallucigenia'' is a long tubular animal with up to ten pairs of slender legs ( lobopods). The first 2 or 3 leg pairs are slender and featureless, while the remaining 7 or 8 pairs each terminate with 1 or 2 claws. Above the trunk region are 7 pairs of rigid conical sclerites (spines) corresponding to the 3rd–9th leg pairs. The trunk is either featureless (''H. sparsa'') or divided by heteronomous annulations (''H. fortis'' and ''H. hongmeia''). The "head" and "t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antennacanthopodia
''Antennacanthopodia'' is a small lobopodian from the Chengjiang biota that dates to about 520 million years ago (Cambrian Stage 3). It is similar to the extant Onychophora (velvet worm) and is the only widely accepted Stem-group, stem-onychophoran lobopodian from the Cambrian period. ''Antennacanthopodia'' had nine pairs of stubby legs, a pair of potential ocelli, and two pairs of Antenna (zoology), antennae. The first pair of antennae were much longer than the second and are still present in modern onychophorans. The identity of the smaller antennae are less clear, but they might be homologous with either the slime papillae or onychophoran jaw. The animal also had diminutive spines on its legs and trunk, highly sclerotised, sclerotized foot pads, and possible pair of tendril-like appendages at the end of its body. Discovery and naming Both fossils of ''Antennacanthopodia'' were excavated from the upper Yu'anshan Member of the Lower cambrian, Lower Cambrian Heilinpu Formation. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
