|Here is a very large and nice Naraoia from the fossil konservat lagerstatte of Chengjiang with some superb details. The Specimen is exposed from the ventral side|
so that the fossils show nice the legs and the attached muscles.
Naraoia belongs to the just recently established trilobite order of Nektaspida. This fossils are also called "soft-shelled trilobites" or also sometimes in older lecture they are called “Leather Trilobites”. This ancient group of Arthropods does have no mineralised exoskeleton so that there are some doubts about there systematic position inside the order of Trilobita. But there are servile indications that they belongs to the Trilobites as well. For example is the general habit and the anatomy of the legs and grils very similait to that of trilobites. Also the Ontogenic mode of growing is nearly the same to Trilobites. All in one the most they seem to referred as Trilobites. There was a similair discussion on the Trilobite order of Agnostida as well.
|Chengjiang, eastern Yunnan Province, South China|
|Size trilobite:||about 23 mm long|
|Age:||Lower Cambrian, Heilinpu Fm., Yu'anshan Member, (about. 522 Mill. y.o.)|