''Xiazhuangocaris'' is an extinct genus of bivalved arthropod known from the

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

aged

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

of Yunnan, China. Only a single specimen (NIGP 172765) is known, around long, which only preserves the anatomy of the carapace and the trunk. The bivalved carpace has a pronounced pair of notches at its front, as well as a posterior notch at its rear. The body had at least 13

tergite A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the Anatomical terms of location#Dorsal and ventral, dorsal ('upper') portion of an arthropod segment other than the head. The Anatomical terms of location#Anterior ...

pleurite A sclerite (Greek , ', meaning "hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instead it refers most commonly ...

rings, which terminate in a pair of rounded

caudal rami The caudal ramus (plural: ''caudal rami'') is a characteristic feature of primitive crustaceans. Located on the anal somite (telson segment), the caudal ramus is a pair of appendage-like or spine-like protrusions. Specific structures which are ro ...

, which are fringed with

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e. The describing authors interpreted the taxon as a member of

Hymenocarina Hymenocarina is an Order (biology), order of extinct marine arthropods known from the Cambrian. They possess bivalved carapaces, typically with exposed posteriors. Members of the group are morphologically diverse and had a variety of ecologies, i ...

, which contains other Cambrian bivalved arthropods.

References

{{Hymenocarina Hymenocarina Cambrian arthropods Fossil taxa described in 2020