''Mollisonia'' is an extinct genus of

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 ...

arthropod 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 ...

. Species are known from the

Burgess Shale 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 ...

, Langston Formation, and

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 ...

of North America, as well as the

Chengjiang Biota The Maotianshan Shales are a series of Early Cambrian deposits in the Chiungchussu Formation, famous for their '' Konservat Lagerstätten'', deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales ...

of China. Twenty-one specimens of ''Mollisonia'' are known from the Greater

Phyllopod bed The Phyllopod bed, designated by USNM locality number 35k, is the most famous fossil-bearing member of the Burgess Shale fossil ''Lagerstätte''. It was quarried by Charles Walcott from 1911–1917 (and later named Walcott Quarry), and was t ...

, where they comprise less than 0.1% of the community. Remains possibly attributable to the genus are also known from the Ordovician

Fezouata Formation The Fezouata Formation or Fezouata Shale is a geological formation in Morocco which dates to the Early Ordovician.

of Morocco and Bøggild Fjord Formation Greenland. An observation published in 2019 suggests this genus is a basal

chelicerate The subphylum Chelicerata (from New Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, horseshoe crabs, and arachnids (including harvestmen, scorpions, spiders, solifuges, ticks, and mite ...

, closer to crown group Chelicerata than members of Habeliida. It is suggested to be closely related to '' Corcorania'', ''

Urokodia ''Urokodia aequalis'' is an extinct genus of arthropod from the early Cambrian. The taxon is only known from the Maotianshan Shales of China based on some 15 specimens. Its segmentation resembles that of a millipede and it possessed head and tai ...

'', and ''

Thelxiope ''Thelxiope'' is a genus of Cambrian and Ordovician arthropod. Four named species are known, the type species ''T. palaeothalassia'' is known from the Burgess Shale, Canada ''T. holmani'' is from the Wheeler Shale of Utah, ''Thelxiope tangi'' fr ...

'', which together form the clade Mollisoniida, which are thought to be closely related to

Chelicerata The subphylum Chelicerata (from New Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, horseshoe crabs, and arachnids (including Opiliones, harvestmen, scorpions, spiders, Solifugae, solif ...

References

External links

* Burgess Shale fossils Cambrian arthropods Prehistoric arthropod genera {{paleo-arthropod-stub