Panlongia was a small-sized marine arthropod. Panlongia lived during the late Lower Cambrian (Botomian) in what is today South China. The genus consists of two species, P. spinosa and P. tetranodus.
Description Panlongia is a flat, long nektaspid, with an oval-shaped non-calcified exoskeleton. Both the head shield (or cephalon) and the tail shield (or pygidium) are semi-circular. In between the cephalon and pygidium are four thoracic body segments (somites). The cephalon occupies approximately ⅓ of the body length, the thorax ¼ and pygidium about 45%.
In Panlongia spinosa, the edge of the exoskeleton carries several small sawtooth-like spines, that are absent in P. tetranodusa.
Distribution Panlongia spinosa is found in the late Lower Cambrian (Botomian) of China (Wulongqing Formation, only at Gaoloufang Kgs-2). Panlongia tetranodusa occurs in the late Lower Cambrian (Botomian) of China (Wulongqing Formation, Gaoloufang Kgs-1, and Shijiangjun Wsh-14, Wuding County, Yunnan, "Guanshan fauna").
Taxonomy The phylogenetic position of Panlongia remained uncertain due to the lack of appendages until 2024, when more well-preserved specimens with appendages narrowed its placement down to as a nektaspid.
Ecology Panlongia tetranodusa occurs with the coeloscleritophoran Allonia sp., the vetulicolian Vetulicola gangtoucunensis, lingulate brachiopods Lingulellotreta malongensis, Diandongia pista, Acrothele rara, and Westonia gubaiensis; radiodonts Houcaris saron and Guanshancaris kunmingensis, hyolith Linevitus malongensis, eocrinoid Wudingeocrinus rarus, Trilobites Redlichia yunnanensis, R. mansuyi, R. noetlingi, R. conica, R. shijiangjunensis, Palaeolenus douvillei, and P. lantenoisi; crustaceans: Tuzoia sinensis, T. tylodesa, Branchiocaris sp., Liangshanella liangshanensis, and Neokunmingella sp., and several other arthropods like Longquania bispinosa, Guangweicaris spinatus; Leanchoilia illecebrosa, Isoxys minor and I. wudingensis.
See also Cambrian explosion Phytophilaspis
References