Naraoiidae is a family, of extinct, soft-shelled trilobite-like arthropods, that belongs to the order Nectaspida. Species included in the Naraoiidae are known from the second half of the Lower Cambrian to the end of the Upper Silurian. The total number of collection sites is limited and distributed over a vast period of time: Maotianshan Shale and Balang Formation (China), Burgess Shale and Bertie Formation (Canada), the Šárka Formation, Emu Bay Shale (Australia), Idaho and Utah (USA). This is probably due to the rare occurrence of the right circumstances for soft tissue preservation, needed for these non-calcified exoskeletons.
Hallucigenia is a genus of Cambrian xenusiids known from articulated fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual appearance and eccentric history of study; when it was erected as a genus, H. sparsa was reconstructed upside down and back to front. Hallucigenia is now recognized as a "lobopodian worm". It is considered by some to represent an early ancestor of the living velvet worms, although other researchers favour a relationship closer to arthropods.
Nectocaris pteryx is a species of possible cephalopod known from the "early Cambrian" Emu Bay Shale and Chengjiang biota, the "middle Cambrian" Burgess Shale.
Haikouella is an agnathan chordate from the Lower Cambrian Maotianshan shales of Chengjiang County in Yunnan Province, China.
Myllokunmingia is a genus of basal chordate from the Lower Cambrian Maotianshan shales of China, thought to be a vertebrate, although this is not conclusively proven. It is 28 mm long and 6 mm high.
Wiwaxia is a genus of soft-bodied animals that were covered in carbonaceous scales and spines that protected it from predators. Wiwaxia fossils – mainly isolated scales, but sometimes complete, articulated fossils – are known from early Cambrian and middle Cambrian fossil deposits across the globe. The living animal would have measured up to 5 cm (2 inch) when fully grown, although a range of juvenile specimens are known, the smallest being 2 millimetres (0.079 in) long.
Naraoia is a genus of small to average size marine arthropods within the family Naraoiidae, that lived from the early Cambrian to the late Silurian period. The species are characterized by a large alimentary system and sideways oriented antennas.
Fuxianhuia protensa is a Lower Cambrian fossil arthropod known from the Chengjiang fauna in China. Its purportedly primitive features have led to its playing a pivotal role in discussions about the euarthropod stem group. Nevertheless, despite being known from many specimens, disputes about its morphology, in particular its head appendages, have made it one of the most controversial of the Chengjiang taxa, and it has been discussed extensively in the context of the arthropod head problem.
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, it bears great similarity to the opabiniids.
Class Xenusia, the Xenusiids, represents the subset of lobopodian worms that fall in the stem-lineage of Onychophora. Their type genus is Xenusion. They have relatively large, annulated, cylindrical bodies. Their lobopod legs have tubercles at their bases. Some have large frontal appendages, although these may represent taphonomic artefacts. Their mouth is terminal or subterminal, and they are marine. They probably represent a grade rather than a clade.
Kuamaia is an extinct genus of artiopodan in the phylum Arthropoda. Fossils of the type species K. lata were discovered in the Chengjiang biota. The closely related congeneric species K. muricata has also been identified there, but neither species has been found elsewhere.
Occacaris oviformis is an extinct nektonic predatory arthropod from the Lower Cambrian Maotianshan shale Lagerstätte. It bears a superficial resemblance to the Cambrian arthropod, Canadaspis, though, was much smaller, and had a pair of "great appendages", with which it may have grasped prey.
Radiodonta is an order of stem-group arthropods that was successful worldwide during the Cambrian period, and included the earliest large predators known. They may referred as radiodonts, radiodontans, radiodontids, anomalocarids, or anomalocaridids, although the latter originally refer to the family Anomalocarididae, which previously included all but recently only a few species of this order. Some of the most famous species of radiodonts are the Cambrian taxa Anomalocaris canadensis, Hurdia victoria, Peytoia nathorsti, and Amplectobelua symbrachiata, the Ordovician Aegirocassis benmoulai and the Devonian Schinderhannes bartelsi.
The palaeoscolecids are a group of extinct ecdysozoan worms resembling armoured priapulids. They are known from the Lower Cambrian to the late Silurian; they are mainly found as disarticulated sclerites, but are also preserved in many of the Cambrian lagerstätten. They take their name from the typifying genus Palaeoscolex.
Vetulicola rectangulata is a species of small, Early Cambrian deuterostome animals from the Chengjiang biota of China.
Strabops is a genus of strabopid, an extinct group of arthropods. Strabops is known from a single specimen from the Late Cambrian of the Potosi Dolomite, Missouri, collected by a former professor, Arthur Thacher. It is classified in the family Strabopidae of the monotypic order Strabopida, a group closely related to the aglaspidids with uncertain affinities. The generic name is composed by the Ancient Greek words στραβός, meaning "squinting", and ὄψῐς, meaning "face".
Paleomerus is a genus of strabopid, a group of extinct arthropods. It has been found in deposits from the Cambrian period. It is classified in the family Strabopidae of the monotypic order Strabopida. It contains two species, P. hamiltoni from Sweden and P. makowskii from Poland. The generic name is composed by the Ancient Greek words παλαιός (palaiós), meaning "ancient", and μέρος (méros), meaning "part".
Cambroraster is an extinct stem-group arthropod, dating to the middle Cambrian, and represented by the single species Cambroraster falcatus. Hundreds of specimens were found in the Burgess Shale, and described in 2019. A large animal at up to 30 cm long, it had a horseshoe-shaped carapace, and presumably fed by sifting through the sediment with its round mouth lined with hooked spines. It is named partially after the fictional Millennium Falcon, which its dorsal carapace resembles. A second species of Cambroraster is known from the Chengjiang Biota of South China, making it the first uncontroversial hurdiid from the Cambrian of China. This species is known only from a juvenile dorsal carapace, so it was not given a specific name.
Squamacula is an extinct arthropod from the Cambrian Series 2, the type species S. clypeata was described in 1997 from the Chengjiang biota. At the time of description there were only two known specimens of S. clypeata, but now there are at least six known specimens. In 2012 a second species S. buckorum was described from the Emu Bay Shale of Australia.
Luohuilinella is an extinct genus of xandarellid artiopodan arthropod known from the Chengjiang biota of China. The type species Luohuilinella rarus was described in 2012 A second species Luohuilinella deletres was described in 2018. Both taxa are rare components of the assemblage. Like other Xandarellids and most artiopodans, it possessed an unmineralised exoskeleton. The type and currently only known specimen of L. rarus is known from a dorsal exoskeleton, around 17 mm long and 9 mm wide which consists of 27 tergites with pronounced pleural spines. L. deletres is much larger, with specimens being over 10 cm long, L. deletres possessed at least 11 pairs of biramous appendages. Both taxa are dorsoventrally flattened, making a benthic or nektobenthic lifestyle probable. Both taxa have pronounced notches in the cephalon to accommodate the stalked eyes.
