| Siphusauctum Temporal range: | |
|---|---|
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| Holotype of S. gregarium | |
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| Fossil of S. lloydguntheri | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Stem group: | Ctenophora |
| Family: | † Siphusauctidae O'Brien & Caron, 2012 |
| Genus: | † Siphusauctum O'Brien & Caron, 2012 |
| Species | |
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Siphusauctum is an extinct genus of filter-feeding animals that lived during the Middle Cambrian about 510 million years ago.
Siphusauctum was a sessile animal that was attached to the substrate by a holdfast. It had a tulip-shaped body, called the calyx, into which it actively pumped water that entered through pores and filtered out and digested organic contents. It grew to a length of only about 20 cm (7.9 in). [1] [2] It is suggested to have primarily consumed microplankton. [3]
Siphusauctum gregarium was described in 2012 from numerous fossils recovered from the "Tulip Beds" strata of the Burgess Shale of Yoho National Park, British Columbia, Canada. The generic name comes Latin siphus ("cup" or "goblet") and auctus ("large"), referring to the general shape and size of the animal. The specific epithet comes from Latin gregalis ("flock" or "herd") referring to the large numbers of specimens recovered. [1] This species is colloquially referred to as the “Tulip Animal” due to its similar shape to the flower, and this colloquial name is also where the Tulip Beds derived their name from, due to the abundance of Siphusauctum fossils found there. [1]
In 2017 a new species, Siphusauctum lloydguntheri, was reported from the Middle Cambrian Spence Shale of Utah. [2]
In its original 2012 description, Siphusauctum was placed as the only member of the family Siphusauctidae, and suggested to have affinities with Bilateria, due to the suggestion that it possessed a digestive tract and anus, characteristic of the group. [1] However, later studies suggested that it was likely a member of the stem-group of Ctenophora (comb jellies) instead, due to sharing characteristic large cillia structures with the group. While living members of Ctenophora are typically free-living pelagic animals, other suggested members of the ctenophore stem-group, like Dinomischus, Daihua and Xianguangia are also sessile filter feeders. [4] [3]
Hyoliths are animals with small conical shells, known from fossils from the Palaeozoic era. They are at least considered as being lophotrochozoan, and possibly being lophophorates, a group which includes the brachiopods, while others consider them as being basal lophotrochozoans, or even molluscs.
Ctenophora comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming, and they are the largest animals to swim with the help of cilia.
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.
Fasciculus vesanus is an extinct species of stem-group ctenophores known from the Burgess Shale of British Columbia, Canada. It is dated to 515 to 505 million years ago and belongs to middle Cambrian strata.
Canadaspis is an extinct genus of bivalved Cambrian arthropod, known from North America and China. They are thought to have been benthic feeders that moved mainly by walking and possibly used its biramous appendages to stir mud in search of food. They have been placed within the Hymenocarina, which includes other bivalved Cambrian arthropods.
Dinomischusis an extinct genus of stalked filter-feeding animals within the Cambrian period, with specimens known from the Burgess Shale and the Maotianshan Shales. While long of uncertain affinities, recent studies have suggested it to be a stem-group ctenophore.
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.
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.
Radiodonta is an extinct order of stem-group arthropods that was successful worldwide during the Cambrian period. Radiodonts are distinguished by their distinctive frontal appendages, which are morphologically diverse and were used for a variety of functions. Radiodonts were among the earliest large predators, 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 gainesi, Cambroraster falcatus and Amplectobelua symbrachiata. The later surviving members include the subfamily Aegirocassisinae from the Early Ordovician of Morocco and the Early Devonian member Schinderhannes bartelsi from Germany.
Tommotiids are an extinct group of Cambrian invertebrates thought to be early lophophorates.
Eolympia is interpreted as an extinct monospecific genus of sea anemone or dinomischid ctenophore which existed in what is now Ningqiang, Shaanxi Province, China during the lower Cambrian period. Its fossils have been recovered from the Kuanchuanpu Formation. The pedicle is long, suggesting the animal engaged in sexual intercourse, though marked perforations imply that reproduction by transverse fission was also quite likely as a more primitive backup.
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. It was first named by Allison C. Daley and Graham E. Budd in 2010, being the type species Caryosyntrips serratus.
Cotyledion tylodes is an extinct, stalked filter-feeder known from the Chengjiang lagerstatten. The living animal reached a couple of centimetres in height, and bore a loose scleritome of ovoid sclerites. Its interpretation has been controversial, but it is currently thought to be a member of the Entoprocta stem group.
Xianguangia is a soft-bodied sea anemone-like fossil animal from the Chengjiang Biota of China.
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.
Scleroctenophora is an extinct class of stem group ctenophores, known from the Chinese Maotianshan shales of Yunnan. It is dated to Cambrian Stage 3 and belongs to late Early Cambrian strata. Scleroctenophorans are easily distinguished from other ctenophores by the presence of an internal skeleton that supports the body.
Hymenocarina is an order of extinct arthropods known from the Cambrian. They possess bivalved carapaces, typically with exposed posteriors. Members of the group are morphologically diverse and had a variety of ecologies, including as filter feeders and as predators. Recent research has generally considered them to be stem or crown group members of Mandibulata, due to the presence of mandibles in some species.
This is a list of the biota of the Burgess Shale, a Cambrian lagerstätte located in Yoho National Park in Canada.
Daihua sanqiong is a possible ancestor of comb jellies. It was a sessile relative to comb jellies. It had combs with cilia just like modern day comb jellies.
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