''Thelxiope'' is a genus of Cambrian and

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chiti ...

. Four named species are known, the type species ''T. palaeothalassia'' is 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 fo ...

, Canada ''T. holmani'' is from the

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 Konzen ...

of Utah, ''Thelxiope tangi'' from the Linyi Lagerstätte of Shandong, China, and ''T. spinosa'', which is known from both the Linyi Lagerstätte and the Wheeler Shale. An indeterminate species is also known from the Ordovician (

Floian The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician epoch. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from to million years ago. The ...

) Fezouata Formation in Morocco. It is a member of Mollisoniida, alongside close relatives ''

Mollisonia ''Mollisonia'' is an extinct genus of Cambrian arthropod. Species are known from the Burgess Shale, Langston Formation, and Wheeler Shale of North America, as well as the Chengjiang Biota of China. Twenty-one specimens of ''Mollisonia'' are ...

, Corcorania'' and ''

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 ...

.'' They are suggested to be stem-

chelicerates 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 ...

References

Burgess Shale fossils Prehistoric arthropod genera {{paleo-arthropod-stub Cambrian genus extinctions