Kazacharthra

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Kazacharthra
Fossil range: Lower Jurassic

Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Branchiopoda
Order:	Kazacharthra Novojilov, 1957
Family:	Ketmeniidae

Species

Ketmenia schultzi
Almatium gusevi
Iliella spinosa
Jeanrogerium sornayi
Kungeja tchakabaevi
Kysyltamia tchiiliensis
Panacanthocaris ketmenia

Kazacharthra is an extinct order of branchiopod crustaceans, closely related to the living order Notostraca (the tadpole shrimp). Kazacharthrans lived in marshes and ponds in Lower Jurassic Kazakhstan (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, 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).

Fossil evidence suggests that the kazacharthrans were descended from notostracans that became isolated in bodies of freshwater in Lower Jurassic Kazakhstan.

The kazacharthrans were distinguished from tadpole shrimp in the arrangement of the compound eyes, and the presence of an enlarged telson. In the latter, the three compound eyes are arranged closely together, while in the former, the front pair was arranged closed together, forming either a dome or bar-like structure, with the third eye directly behind the front pair. Tadpole shrimp do not have an enlarged telson, while the kazacharthrans had a relatively large shield or flap-like telson, the exact shape differing among species.

There are seven species, in seven genera, currently described, placed within a single family, Ketmeniidae (invalid name/synonym = Paratriopsidae).