''Caryosyntrips'' ("

nutcracker A nutcracker is a tool designed to open nuts by cracking their shells. There are many designs, including levers, screws, and ratchets. The lever version is also used for cracking lobster and crab shells. A decorative version portrays a person w ...

") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

radiodont Radiodonta is an extinct Order (biology), 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 ...

which known from

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and Spain during the middle

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 ...

. ''Caryosyntrips'' is known only from its 14-segmented frontal appendages, which resemble nutcrackers, recovered from the

Burgess Shale Formation The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest foss ...

, Canada

Wheeler Shale The Wheeler Shale (named by Charles Walcott) is a Cambrian ( 507 Ma) fossil locality world-famous for prolific agnostid and ''Elrathia kingii'' trilobite remains (even though many areas are barren of fossils) and represents a Konzent ...

and

Marjum Formation The Marjum Formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale The Burgess S ...

, United States, and Valdemiedes Formation, Spain. It was first named by Allison C. Daley, Graham E. Budd in

2010 File:2010 Events Collage New.png, From top left, clockwise: The 2010 Chile earthquake was one of the strongest recorded in history; The Eruption of Eyjafjallajökull in Iceland disrupts air travel in Europe; A scene from the opening ceremony of ...

and the type species is ''Caryosyntrips serratus''. ''Caryosyntrips'' is thought to have used their appendages in a scissor-like grasping or slicing motion, and were probably

durophagous Durophagy is the eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs. It is mostly used to describe fish, but is also used when describing reptiles, including fossil tu ...

, feeding on hard-shelled organisms. Due to the unusual morphology of the frontal appendages and the limited extent of known remains, its position within Radiodonta remains uncertain.

References

External links

* Anomalocaridids Burgess Shale fossils Fossil taxa described in 2010 Cambrian genus extinctions {{paleo-arthropod-stub