Caryosyntrips Temporal range:
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Frontal appendages of Caryosyntrips | |
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Speculative life restoration as a radiodont | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Stem group: | Arthropoda |
Genus: | †Caryosyntrips Daley & Budd, 2010 |
Type species | |
Caryosyntrips serratus Daley & Budd, 2010
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species | |
Caryosyntrips ("nutcracker") is an extinct genus of stem-arthropod which known from Canada, United States and Spain during the middle Cambrian.[1]
Caryosyntrips was first named by Allison C. Daley, Graham E. Budd in 2010 and the type species is Caryosyntrips serratus.[3] Multiple species had been recovered from the Burgess Shale Formation, Canada, Wheeler Shale and Marjum Formation, United States, and Valdemiedes Formation, Spain.[1][4] The latter contain a large specimen, which was initially misidentified as a body remain of lobopodian ("Mureropodia apae").[5][1][6][2]
Caryosyntrips is known only from its 14-segmented frontal appendages, which resemble nutcrackers, with the endite (ventral spine)-bearing margin facing each other. the bell-shaped bases might represent movable articulations with the animal's head. Details of endites, terminal spines, segmental boundaries and outer margins differ between species.[1] Other structures remain unknown, although a specimen with paired appendages possibly contain other fragmental head sclerites as well.[3][4]
Caryosyntrips is thought to have used their frontal appendages in a scissor-like grasping or slicing motion, and were probably durophagous, feeding on hard-shelled organisms.[1]
As of 2010s, Caryosyntrips was long considered to be a basal radiodont of uncertain position, usually resolved in a polytomy between euarthropod and radiodont branches.[7][8][9][2][10][11] however more recent papers have found that it may sit outside of the monophyletic Radiodonta all together.[11][12] Due to the unusual morphology of the frontal appendages and the limited extent of known remains, its position within the arthropod stem-group remains uncertain.[1][12]
Panarthropoda |
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