Megacheira

Alalcomenaeus is one of the most widespread and longest-surviving arthropod genera of the Early and Middle Cambrian. Known from over 300 specimens in the Burgess Shale and the Chengjiang biota. It is a member of the family Leanchoiliidae in the group Megacheira.

Megacheira (from Ancient Greek μέγας (mégas), meaning "great", and χείρ (kheír), meaning "hand", also historically great appendage arthropods) is an extinct class of predatory arthropods defined by their possession of spined "great appendages". Their taxonomic position is controversial, with studies generally either considering them stem-group euarthropods, or stem-group chelicerates. The homology of the great appendages to the cephalic appendages of other arthropods is also controversial. Uncontested members of the group were present in marine environments worldwide from the lower Cambrian to

Leanchoilia is a megacheiran marine arthropod known from Cambrian deposits of the Burgess Shale in Canada and the Chengjiang biota of China.

Yohoia is an extinct genus of fossil megacheiran arthropod from the Cambrian period. The type species, Yohoia tenuis, has been found in the Burgess Shale formation of British Columbia. 711 specimens of Yohoia are known from the Greater Phyllopod bed, where they comprise 1.35% of the community. In 2015, Conway Morris et al. reported another species, Y. utahana, from the Marjum Formation, Utah.

Parapeytoia is a genus of Cambrian arthropod. The type and only described species is Parapeytoia yunnanensis, which lived over 518 million years ago (Cambrian Stage 3) in the Maotianshan shales of Yunnan, China. Unidentified fossils from the same genus have also been discovered from the nearby Wulongqing Formation (Cambrian Stage 4).

Haikoucaris is a genus of megacheiran arthropod that contains the single species Haikoucaris ercaiensis. It was discovered in the Cambrian Chengjiang biota of China.

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Kootenichela deppi is an extinct arthropod described from the Middle Cambrian of the Kootenay National Park, Canada. It is originally considered to be a member of "great appendage arthropods", although subsequent studies questioned its affinity. Kootenichela appears to be the sister taxon of Worthenella, from cladistic analysis.

species of Cambrian arthropods

Yawunik is an extinct genus of Cambrian megacheiran ("Great appendage" arthropod) known from the Burgess Shale in Canada ( Marble Canyon locality). The type species has been named Yawunik kootenayi after the Kootenay, both a geographic area (and National Park, where the fossil was found) and North American First Nation, also known as the Ktunaxa. The genus name is derived from , the name of a primordial sea monster in Ktunaxa mythology. The fossil dates back to 508 million years ago.