Chengjiang Misszhouia with antennae, gut and legs

Misszhouia longicaudata

Phylum Arthropoda, Naraoiidae Trilobite Relatives

Geological Time: Early Cambrian (~525 million years ago)

Size: 40 mm long

Fossil Site: Chengjiang Maotianshan Shales, Mafang Section, Yu’anshan Member, Anning, Kunming, Yunnan Province, China

MisszhouiaDescription: The exact taxonomic status of this arthropod is in dispute. It has been termed a “trilobitomorph” by some researchers, showing their beliefs in its close affinity with the trilobites. While the Trilobitoorpha was listed in the Treatise, most now consider that this subphylum is invalid, a catchall much Misszhouia antennaelike some of the dustbin terms used by Walcott for a number of the Burgess Shale fauna. Whittington termed it a “soft-bodied trilobite”’ but that belief is not supported at present. Their similarity in appearance to the Agnostida is purely a result of convergence. Two large Misszhouia legsgroupings of the Paleozoic arthropods are currently in favor: the Crustaceomorpha (which includes Waptia) and the Arachnomorpha, dominated by the trilobites. The Naraoiidae are arachnomorphs and include Misszhouia andSoft Bodied Trilobite Naraoia. Misszhouia longicaudata was initially placed within Naraoia, but was given its own genus based upon differences between it and Naraoia compacta of the Burgess Shale. The species is one found in several locations within Yunnan Province. This one is a quite large example which shows the outline of the cuticle, the central gut line, antennae, and a fringe of delicate biramous appendages.

Also see: Chengjiang Biota for Faunal List Chengjiang Fossils Trilobite Relatives

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