''Kuamaia'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of

artiopodan 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 ...

in the

phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature f ...

Arthropoda 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 ...

. Fossils of the type species ''K. lata'' were discovered in the Chengjiang biota. The other

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

in the genus,''K. muricata'' has also been identified there, but neither species has been found elsewhere. ''Kuamaia lata'' was a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

arthropod and a mobile hunter and scavenger. A spiny section on ''K. lata'''s legs is presumed to have allowed it to tear apart food.

Morphology

''Kuamaia lata'' has an oval dorsal

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 ...

shape, with a gradual decline from the somewhat elevated medial axis of the animal to the exoskeleton edge. ''K. lata'' appears smooth, with little space between

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 low-profile pleural spines. Some fusion of parts of the exoskeleton is evident, but there is some discussion as to what degree this occurred. The tail segment has three more prominent spines, two being lateral and one axial. The largest fossil ''K. lata'' was at least 10 cm long, excluding

appendages An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...

. On the underside of ''K. lata,'' opposite the dorsal head shield, there is also a ventral

sclerite 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 ...

. ''K. lata'' appears to have approximately 15 pairs of

biramous The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. Many of the terms used for arthropod leg segments (called podomeres) are of Latin origin, and may be confused with terms for bones: ''coxa'' (meaning hip, plu ...

legs, 3 originating from the head shield, 1 from each of the seven tergites that make up ''K. lata's''

thorax 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 cre ...

, and another 5 from the tail segments. The ramuses, also known as the exopods of the biramous legs, acted as the gills of ''K. lata.'' These gills were made up of many lamellae, which facilitated gas exchange. These lamellae were packed together in rows on each exopod. ''K. lata'' had a lower number of these, with an average number of 22 lamellae per exopod, compared to an average of 50 in other arthropods.

References

{{Taxonbar, from=Q80563553 Artiopoda