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Cambroernid
The Cambroernida are a clade of Paleozoic animals with coiled bodies and filamentous tentacles. They include a number of early to middle Paleozoic (Cambrian to Devonian) 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. Description Cambroernids encompass three particular types of enigmatic animals first appearing in the Cambrian: ''Herpetogaster'' (the type genus), ''Phlogites'', and the Eldonioidea. They are united by a set of common features including at least one pair of bifurcated or divided oral tentacles, and a large stomach and narrower intestine enclosed together in a clockwise-coiled sac. Taxonomy and evolution Body coiling increased throughout this group's evolution. ''Herpetogaster'' has a segmented and clockwise-cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phlogites
''Phlogites'' is a member of the extinct ambulacrarian stem group Cambroernida, occupying an intermediate position between the basal ''Herpetogaster'' and the more derived Eldonioidea. It is known from the Cambrian, Lower Cambrian Haikou Chengjiang County, Chengjiang deposits of China. Description Phlogites was a cup-shaped animal with a branching tentacular feeding system leading to a dextrally coiled gut with a lateral anus. Sources differ as to the number of tentacles, with two, three, three or five, or four or five tentacles said to be on the anterior part of the calyx (anatomy), calyx. Smooth semi-circular lobes are present between the tentacles. Compared to the earlier-diverging cambroernid ''Herpetogaster'', ''Phlogites'' lacked segmentation and had a more massive stolon that is contiguous with the body. The coiling present in the external form of ''Herpetogaster'' became internal, except for a small lobate extension with the anus opening laterally. The tentacles of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotadiscus
''Rotadiscus'' is a genus of discoidal animal known from the Cambrian Chengjiang biota and classified with the eldonioids. As with other eldonioids, it was originally thought to have been pelagic, but is now thought to be benthic. In addition to the type species ''R. grandis'', two other ''Rotadiscus'' species have been proposed. The first is known only from one complete juvenile specimen and a few fragments, and was originally described as "''Brzechowia'' sp." It remains without a formal species name, but has been transferred to ''Rotadiscus''. The species initially described as ''R. guizhouensis'' has since been reassigned to the genus '' Pararotadiscus''. A 2023 cladistic analysis based on new fossils places ''Rotadiscus'', along with other eldonioids, as stem-group ambulacraria Ambulacraria , or Coelomopora , is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis sugges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambulacraria
Ambulacraria , or Coelomopora , is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 million years ago. The Ambulacraria are part of the deuterostomes, a clade that also includes the many Chordata, and the few extinct species belonging to the Vetulicolia. Phylogeny The two living clades with representative organisms are: * Echinodermata (sea stars, sea urchins, brittle stars, sea cucumbers, feather stars, sea lilies, etc.) * Hemichordata ( acorn worms (Enteropnuesta) and Pterobranchia (including Graptolithina)) (These together sometimes are called the ''lower deuterostomes''.) Whether the Xenacoelomorpha clade is the sister group to the Ambulacraria remains a contentious issue, with some authors arguing that the former should be placed more basally among metazoans, and other authors asserting that the best choice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eldonioidea
Eldonioids or velumbrellids are an extinct clade of disc-shaped cambroernids, the Eldonioidea (or Velumbrellida), which lived in the early to middle Paleozoic (Cambrian to Devonian). 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. Anatomy Eldonioids are characterized by their "medusoid" (jellyfish-shaped) bodies, with the form of a shallow dome opening below to an offset mouth supplemented by filamentous tentacles. Internally, they have a distinctive C-shaped cavity encompassing the gut, as well as hollow radial (radiating) structures arranged around a central ring canal. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paropsonema
''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. A specimen described in 2018 may represent an additional species, but has been tentatively assigned to ''P. cryptohya''; it represents the youngest described paropsonemid. The species ''Discophyllum mirabile'' has been thought to be closer to ''Paropsonema'' than to the sole previously-described species of ''Discophyllum'', ''D. peltata''. As a result, sources treat it as ''Paropsonema mirabile''. 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. Regardless, ''Paropsonema'' and ''Discophyllum'' are grouped together informally as "paropsonemids." References Works cited * * * Cam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotadiscidae
Eldonioids or velumbrellids are an extinct clade of disc-shaped cambroernids, the Eldonioidea (or Velumbrellida), which lived in the early to middle Paleozoic (Cambrian to Devonian). 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. Anatomy Eldonioids are characterized by their "medusoid" (jellyfish-shaped) bodies, with the form of a shallow dome opening below to an offset mouth supplemented by filamentous tentacles. Internally, they have a distinctive C-shaped cavity encompassing the gut, as well as hollow radial (radiating) structures arranged around a central ring canal. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eldonia
''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. Description It takes the form of a round, medusoid disk (which originally led to suggestions of a jellyfish affinity) with a C-shaped gut trace. The gut is recalcitrant and can be extracted using Hydrofluoric acid. A specimen from the Lower Ordovician Madaoyu Formation in Hunan, South China, can be interpreted as the incomplete body of ''Eldonia'' or the similar animal. However, its annulation, the structure of the intestine and the shape of the body are more similar to those of '' Ottoia''. Classification Walcott's original i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eldonioid
Eldonioids or velumbrellids are an extinct clade of disc-shaped cambroernids, the Eldonioidea (or Velumbrellida), which lived in the early to middle Paleozoic (Cambrian to Devonian). 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. Anatomy Eldonioids are characterized by their "medusoid" (jellyfish-shaped) bodies, with the form of a shallow dome opening below to an offset mouth supplemented by filamentous tentacles. Internally, they have a distinctive C-shaped cavity encompassing the gut, as well as hollow radial (radiating) structures arranged around a central ring canal. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seputus
''Seputus'' is a discoid fossil from the Ordovician that may represent an eldonioid cambroernid The Cambroernida are a clade of Paleozoic animals with coiled bodies and filamentous tentacles. They include a number of early to middle Paleozoic (Cambrian to Devonian) genera noted as "bizarre" or "orphan" taxa, meaning that their affinities wi .... References Ordovician invertebrates Cambroernids {{paleo-invertebrate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellostomites
''Stellostomites'' is a discoidal animal known from the Cambrian Chengjiang biota The Maotianshan Shales () are a series of Early Cambrian sedimentary deposits in the Chiungchussu Formation or Heilinpu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized orga .... It is classified with the eldoniids, and considered a junior synonym of ''Eldonia'' by some authors. References Cambroernids Cambrian animals of Asia {{cambrian-animal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinodermata
An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as larvae, as adults echinoderms are recognisable by their usually five-pointed radial symmetry (pentamerous symmetry), and are found on the sea bed at every ocean depth from the intertidal zone to the abyssal zone. The phylum contains about 7,600 living species, making it the second-largest group of deuterostomes after the chordates, as well as the largest marine animal, marine-only phylum. The first definitive echinoderms appeared near the start of the Cambrian. Echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the deep sea, as well as continental shelf, shallower oceans. Most echinoderms are able to asexual reproduction, reproduce asexually and regeneration (biology), regenerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
