Cobitis hellenica is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of ray-finned fish in the true loach family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (Cobitidae). It is endemic to Greece

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

..

It belongs to the subgenus

Subgenus

In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...

 Bicanestrinia, together with C. arachthosensis

Cobitis arachthosensis

Cobitis arachthosensis is a species of ray-finned fish in the true loach family . It is endemic to Greece..It belongs to the subgenus Bicanestrinia, together with C. hellenica, C. meridionalis and C. trichonica...

, C. meridionalis

Cobitis meridionalis

Cobitis meridionalis is a species of ray-finned fish in the Cobitidae family. It is found in Albania, Greece, and the Republic of Macedonia.Its natural habitat is freshwater lakes. It is threatened by habitat loss.-Source:...

and C. trichonica

Cobitis trichonica

Cobitis trichonica is a species of ray-finned fish in the Cobitidae family.It is found only in Greece.It is threatened by water abstraction. This species is short-lived and lives in lakes and lowland water courses with little current.-Source:...

. According to cladistic analysis of DNA sequence

DNA sequence

The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...

 data (nDNA RAG-1 and S7 ribosomal protein

Ribosomal protein

A ribosomal protein is any of the proteins that, in conjunction with rRNA, make up the ribosomal subunits involved in the cellular process of translation. A large part of the knowledge about these organic molecules has come from the study of E. coli ribosomes. Most ribosomic proteins have been...

 intron

Intron

An intron is any nucleotide sequence within a gene that is removed by RNA splicing to generate the final mature RNA product of a gene. The term intron refers to both the DNA sequence within a gene, and the corresponding sequence in RNA transcripts. Sequences that are joined together in the final...

 1, and mtDNA cytochrome b

Cytochrome b

Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...

), the first of these is an extremely close relative and might arguably be included in the present species. C. arachthosensis is only found in the Arachthos River

Arachthos River

The Arachthos is a river in eastern Epirus in Greece that flows from the Pindus mountains and begins in the area southeast of Metsovo in the Ioannina Prefecture near the Trikala Prefecture and flows by numerous village including Elliniko...

 basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

, parapatric to the range of C. hellenica.

Its natural habitat

Habitat

* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

s are the Louros and Thiamis River basins. It is threatened by habitat loss.