Tanymastix is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of anostracan crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, characterised by their lenticular (lentil

Lentil

The lentil is an edible pulse. It is a bushy annual plant of the legume family, grown for its lens-shaped seeds...

-shaped) eggs. It comprises three species. Tanymastix stagnalis

Tanymastix stagnalis

Tanymastix stagnalis is a species of Anostraca that lives in temporary pools across Europe. It may reach up to in some areas and has 11 pairs of bristly, flattened appendages. It swims upside-down and filters food particles from the water...

has a wide distribution across Europe and North Africa. T. motasi is endemic to Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 and Macedonia

Republic of Macedonia

Macedonia , officially the Republic of Macedonia , is a country located in the central Balkan peninsula in Southeast Europe. It is one of the successor states of the former Yugoslavia, from which it declared independence in 1991...

, while T. stellae was endemic to Sardinia

Sardinia

Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...

. The type locality of T. stellae has since been destroyed and the species is believed to be extinct

Extinction

In biology and ecology, extinction is the end of an organism or of a group of organisms , normally 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 recover may have been lost before this point...

; reports of T. stellae surviving on Corsica

Corsica

Corsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....

have not been confirmed, despite repeated attempts.