''Bailongia'' is an extinct genus of

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 ...

known from a single species ''Bailongia longicaudata'' (''longicaudata'' from Latin: "long-tailed") found in the

Cambrian Stage 4 Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on ...

aged Guanshan Biota of

Yunnan Yunnan , () is a landlocked Provinces of China, province in Southwest China, the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is ...

, China. It was around 5mm long and had a large head shield, nine overlapping tapering

tergites A ''tergum'' (Latin for "the back"; plural ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'mar ...

and a relatively elongate tailspine. It has been recovered in a relatively basal position within

Artiopoda The Artiopoda is a grouping of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilo ...

, more derived than '' Squamacula'' or Protosutura, but outside Trilobitomorpha or Vicissicaudata.

Phylogeny

After Jiao et al. 2021.

References

Artiopoda Cambrian arthropods of Asia Cambrian China Paleontology in Yunnan Fossil taxa described in 2021 Cambrian genus extinctions {{Paleo-arthropod-stub