''Panlongia'' was a small-sized (up to 2 cm)

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 ...

, with an oval-shaped non-

calcified Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...

. Both the head shield (or

cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont Company. Baldino s ...

) and the tail shield (or pygidium) are semi-circular. In between the cephalon and pygidium are four

thoracic The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...

body segments ( somites). The cephalon occupies approximately ⅓ of the body length, the thorax ¼ and pygidium about 45%. ''Panlongia'' lived during the late Lower Cambrian (Botomian) in what is today South China. 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'' remains uncertain, because the appendages remain unknown sofar. ''Panlongia'' cannot yet with confidence be assigned to the Helmetiida or the Nektaspida, as was initially suggested.

Ecology

''Panlongia tetranodusa'' occurs with the coeloscleritophoran ''Allonia sp.'', the

vetulicolia VetulicoliaThe taxon name, Vetulocolia, is derived from the type genus, ''Vetulicola'', which is a compound Latin word composed of ''vetuli'' "old" and ''cola'' "inhabitant". is a taxon (either phylum or subphylum in rank) encompassing several ex ...

n ''Vetulicola gangtoucunensis'', lingulate brachiopods ''Lingulellotreta malongensis'', ''Diandongia pista'', ''Acrothele rara'', and ''Westonia gubaiensis''; dinocaridid '' Anomalocaris saron'',

hyolith Hyoliths are animals with small conical surface, conical animal shell, shells, known as fossils from the Palaeozoic era. They are at least considered as lophotrochozoan, and possibly being lophophorates, a group which includes the brachiopods, w ...

''Linevitus malongensis'',

eocrinoid The Eocrinoidea are an extinct class of echinoderms that lived between the Early Cambrian and Late Silurian periods. They are the earliest known group of stalked, arm-bearing echinoderms, and were the most common echinoderms during the Cambrian. ...

''Wudingeocrinus rarus'',

Trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

s '' Redlichia yunnanensis'', ''R. mansuyi'', ''R. noetlingi'', ''R. conica'', ''R. shijiangjunensis'', '' Palaeolenus douvillei'', and ''P. lantenoisi'';

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

: ''Tuzoia sinensis'', ''T. tylodesa'', ''Branchiocaris sp.'', ''Liangshanella liangshanensis'', and ''Neokunmingella sp.'', and several other arthropods like ''Longquania bispinosa'', ''Guangweicaris spinatus''; '' Leanchoilia illecebrosa'', '' Isoxys minor'', ''I. wudingensis'' and ''Gangtoucunia aspera''.

References

{{Taxonbar, from=Q7131336 Maotianshan shales fossils Cambrian arthropods

Distribution

Taxonomy

Ecology

See also

References