Temporal range: Upper Triassic–Lower Jurassic
Kazacharthra is an extinct order of branchiopod crustaceans that appear to be closely related to the living order Notostraca (the tadpole shrimp). Kazacharthrans lived in marshes and ponds in the Upper Triassic of Western China and Mongolia, and in Lower Jurassic Kazakhstan (where their fossils were first found, hence the name). It is presumed that the kazacharthrids lived much like their living relatives, in that they were opportunistic omnivores that fed on any available food source, from bacterial biofilms to detritus to smaller animals that could be overpowered (i.e., fairy shrimp, small or recently hatched amphibian larvae, smaller members of the same species, etc.).
The kazacharthrans are distinguished from tadpole shrimp in that they were much larger (carapace length ranging from 0.6 to 5 centimeters), had uniquely shaped, heavily sclerotized, heavily mineralized carapaces, and plate-shaped telsons The carapace, or headshield had a distinctive pattern of tubercles, typically with a central-anteriorly located tubercle that may or may not have housed the compound eyes, and other, distinctively shaped tubercles that may represent attachment sites for mandibles.
There are seven genera recognized, placed within a single family, Ketmeniidae (invalid name/synonym = Paratriopsidae).
- Treatise on Invertebrate Paleontology, Arthropoda, Part Q