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Lobopod
The lobopodians, members of the informal group Lobopodia (from the Greek, meaning "blunt feet"), or the formally erected phylum Lobopoda Cavalier-Smith (1998), 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, worm-like fossil panarthropods such as ''Aysheaia'' and ''Hallucigenia''. 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 (Arthropoda, Tardigrada and Onychophora) are thought to have evolved from lobopodian ancestors. Definitions The Lobopodian concept varies f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panarthropods
Panarthropoda is a proposed animal clade containing the extant phyla Arthropoda, Tardigrada (water bears) and Onychophora (velvet worms). 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 close relationship between onychophorans and arthropods is widely agreed upon, but the position of tardigrades is more controversial. Some phylogenomic studies have fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diania
''Diania'' is an extinct genus of lobopodian animal 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 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 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 old. Specifically, they come from the Yu'anshan Formation, dated to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euarthropoda
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. 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. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is "ladder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropoda
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. Arthropods are bilaterally symmetrical and their body possesses an external skeleton. 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. Some species have wings. They are an extremely diverse group, with up to 10 million species. The haemocoel, an arthropod's internal cavity, through which its haemolymph – analogue of blood – circulates, accommodates its interior organs; it has an open circulatory system. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. Their nervous system is "lad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aysheaia
''Aysheaia'' is an extinct genus of soft-bodied lobopod, known from the middle Cambrian of North America, with an average body length of 1–6 cm. Anatomy ''Aysheaia'' has ten body segments, each of which has a pair of spiked, annulate legs. The animal is segmented, and looks somewhat like a bloated caterpillar with a few spines added on — including six finger-like projections around the mouth and two grasping legs on the "head". Each leg has a subterminal row of about six curved claws. No jaw apparatus is evident. A pair of legs marks the posterior end of the body, unlike in onychophorans where the anus projects posteriad; this may be an adaptation to the terrestrial habit. Ecology Based on its association with sponge remains, it is believed that ''Aysheaia'' was a sponge grazer and may have protected itself from predators by seeking refuge within sponge colonies. ''Aysheaia'' probably used its claws to cling to sponges. A terminal mouth is also seen in tardigrades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerygmachela
''Kerygmachela kierkegaardi'' is a gilled lobopodian from the Cambrian Stage 3 aged Sirius Passet Lagerstätte in northern Greenland. Its anatomy strongly suggests that it, along with its relative '' Pambdelurion whittingtoni'', was a close relative of radiodont (anomalocaridids) and euarthropods. The generic name "Kerygmachela" derives from the Greek words ''Kerygma'' (proclamation) and ''Chela'' (claw), in reference to the flamboyant frontal appendages. The specific name, "kierkegaardi" honors Danish philosopher Søren Kierkegaard. Morphology The head of ''Kerygmachela'' possesses a pair of well-developed frontal appendages which correspond to those of other dinocaridids and siberiid lobopodians. Each of them terminates in a series of long spines. A pair of sessile, slit-like compound eyes is located slightly behind the base of these appendages. A small anterior-facing mouth is located below the head and bears a pair of stylet-like structures. The head also possesses ... [...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. 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 Geological Society of America, and published the next year in a popular magazine ''Rotun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luolishania
''Luolishania'' is an extinct genus of lobopodian worm 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 Chengjiang L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jianshanopodia
''Jianshanopodia decora'' is a Cambrian lobopodian. Its frontal, grasping appendages bear wedge-shaped plates. Its limbs branch, instead of being tipped with claws as many lobopods' are. It has a sediment-filled gut surrounded by serially repeated diverticulae. It is thought to have sucked up prey with its short 'trunk'. It mainly crawled on the sea floor, but could swim when necessary. Its mouth resembles those of anomalocaridids and priapulid Priapulida (priapulid worms, from Gr. πριάπος, ''priāpos'' 'Priapus' + Lat. ''-ul-'', diminutive), sometimes referred to as penis worms, is a phylum of unsegmented marine worms. The name of the phylum relates to the Greek god of fertility ...s. References Prehistoric protostome genera Fossil taxa described in 2006 Lobopodia {{Cambrian-animal-stub Cambrian genus extinctions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microdictyon
''Microdictyon'' is an extinct armoured worm-like animal coated with net-like scleritic plates, known from the Early Cambrian Maotianshan shale of Yunnan China and other parts of the world. ''Microdictyon'' is part of the ill-defined taxon – Lobopodia – that includes several other odd worm-like animals that resembling worm with legs, such as '' Hallucigenia'', '' Onychodictyon'', ''Cardiodictyon'', '' Luolishania'', and ''Paucipodia''. The isolated sclerites of ''Microdictyon'' are known from other Lower Cambrian deposits. ''Microdictyon'' sclerites appear to have moulted; one sclerite seems to have been preserved during ecdysis.Figured in ''Microdictyon sinicum'' (Chen, Hou and Lu, 1989) is typical. The wormlike animal has ten pairs of sclerites (suggestions that these may be eyes or eye-like structures have no weight) on the sides, matched to a pair of tentacle-like feet below. The head and posterior are tubular and featureless. Species composition *Type s ... [...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 in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pambdelurion
''Pambdelurion'' is an extinct genus of panarthropod from the Cambrian aged Sirius Passet site in northern Greenland. Like the morphologically similar ''Kerygmachela'' from the same locality, ''Pambdelurion'' is thought to be closely related to arthropods, combining characteristics of " lobopodians" with those of primitive arthropods. Description ''Pambdelurion'' was large for a Cambrian animal, and is estimated to have reached a length of . ''Omnidens'', an organism from China that closely resembles ''Pambdelurion'' and may even be synonymous with it, reached even larger sizes, estimated to be based on the proportions of ''Pambdelurion''. The head of ''Pambdelurion'' bore a large pair of frontal appendages, homologous to the antennae of onychophorans and frontal appendages of radiodonts. These frontal appendages were weakly muscled and relatively soft, suggesting they may have served primarily as sensory organs, rather than for grasping prey. Between the appendages are a pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
