Tamisiocarididae is a family of

radiodonts 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 origi ...

, extinct marine animals related to

arthropods Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

, that bore finely-spined appendages that were presumably used in filter-feeding. When first discovered, the clade was named Cetiocaridae after a

speculative evolution Speculative evolution is a genre of speculative fiction and an artistic movement focused on hypothetical scenarios in the evolution of life, and a significant form of fictional biology. It is also known as speculative biology and it is referred ...

artwork, ''Bearded Ceticaris'' by John Meszaros, that depicted a hypothetical filter-feeding radiodont at a time before any were known to exist. However, the family name was not valid according to the

International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the ...

, as no real genus named "Cetiocaris" exists, and in 2019 it was formally replaced by the name Tamisiocarididae, after the only valid genus of the clade at the time. The family is only known from

Series 2 Series 2 could refer to: * Apple Watch Series 2, a smart watch by Apple * Aston Martin Lagonda Series 2, the automobile model * Aston Martin V8 Series 2, the automobile model * BMW 2 Series, the automobile model line * GeForce 2 series, line of nV ...

of the

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

, unlike other radiodont families, which persisted longer into the Cambrian. All known species would have lived in tropical or subtropical waters, suggesting a preference for warmer waters.

Description

Like most radiodonts, cetiocarids have spiny frontal appendages. However, in this family the auxiliary spines are fine and densely-arranged, which are modified for use in

filter feeding Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

like modern basking sharks and mysticete whales. For example, ''

Tamisocaris ''Tamisiocaris'' (from Latin ''tamisium'', sieve, and Greek ''karis'', crab, shrimp) is a radiodont genus initially only known from frontal appendages from the Buen Formation in Sirius Passet. Further specimens revealed that the frontal appe ...

'' is estimated to have fed on prey roughly a millimeter in size.

Classification

Tamisiocarididae was originally named Cetiocaridae. In the 2013

speculative Speculative may refer to: In arts and entertainment *Speculative art (disambiguation) *Speculative fiction, which includes elements created out of human imagination, such as the science fiction and fantasy genres **Speculative Fiction Group, a Per ...

paleoart Paleoart (also spelled palaeoart, paleo-art, or paleo art) is any original artistic work that attempts to depict prehistoric life according to scientific evidence. Works of paleoart may be representations of fossil remains or imagined depiction ...

book ''All Your Yesterdays'', paleoartist John Meszaros depicted a hypothetical filter-feeding anomalocaridid he named "Ceticaris". This artwork inspired the name of Cetiocaridae. However, as no genus "Cetiocaris" actually exists, the name Cetiocaridae does not comply with article 29 of the

and is invalid. The family Tamisiocarididae was subsequently devised as a replacement name for the clade. Cetiocaridae was originally defined phylogenetically as all species more closely related to ''

Tamisiocaris borealis ''Tamisiocaris'' (from Latin ''tamisium'', sieve, and Greek ''karis'', crab, shrimp) is a radiodont genus initially only known from frontal appendages from the Buen Formation in Sirius Passet. Further specimens revealed that the frontal append ...

'' than to ''

Anomalocaris canadensis ''Anomalocaris'' ("unlike other shrimp", or "abnormal shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group arthropods. The first fossils of ''Anomalocaris'' were discovered in the ''Ogygopsis'' Shale of the Stephen F ...

'', '' Amplectobelua symbrachiata'', or ''

Hurdia victoria ''Hurdia'' is an extinct genus of hurdiid radiodont that lived 505 million years ago during the Cambrian Period. As a radiodont like ''Peytoia'' and ''Anomalocaris'', it is part of the ancestral lineage that led to euarthropods. Description ' ...

''.

Distribution

Tamisocaridid fossils have been found in the

Emu Bay Shale The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte (fossil beds with soft tissue preservation). It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Sirius Passet Sirius Passet is a Cambrian Lagerstätte in Peary Land, Greenland. The Sirius Passet Lagerstätte was named after the Sirius sledge patrol that operates in North Greenland. It comprises six places in Nansen Land, on the east shore of J.P. Koch F ...

lagerstätte of

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

, and

Kinzers Formation The Kinzers Formation is a geologic formation in Pennsylvania. It preserves fossils dating back to the Cambrian Period. The base of the Kinzers Formation is primarily a dark-brown shale. The middle is a gray and white spotted limestone and, lo ...

of the United States. Their fossils date to stage 3 and stage 4 of the

References

External links

''Bearded Ceticaris'' by John Meszaros
{{Taxonbar, from=Q16975582 Cambrian arthropods Prehistoric arthropod families