''Esox cisalpinus'', the southern pike, is a species of

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels of s ...

known from central and northern

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, southeastern

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

and

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

, and it might also occur in the western

Balkans The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...

. It has traditionally been considered a southern European variant of the widespread

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus '' Esox'' (the pikes). They are typical of brackish and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are known simply as a ...

(''Esox lucius''), but was described as a separate species in 2011. Like the northern pike, southern pike are an important species for recreational fisheries and for its role as a

top predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...

in freshwater ecosystems.

Taxonomy

''Esox cisalpinus'' was distinguished from ''Esox lucius'' (northern pike) and described scientifically as a new species in 2011 independently by two research groups. The description by Bianco & Delmastro was printed earlier,Bianco, P. G. & Delmastro, G. B. (2011): ''Recenti novità tassonomiche riguardanti i pesci d’acqua dolce autoctoni in Italia e descrizione di una nuova specie di luccio.'' Researches on Wildlife Conservation (IGF publ.), 2 (suppl.): 1–13. PDF and the name ''Esox cisalpinus'' is therefore accepted, whereas the alternative name published somewhat later by Lucentini et al., ''Esox flaviae'', is considered a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

. Lucentini et al. explicitly tested the hypothesis that the different phenotypes of the pike, geographically isolated in Europe, represent two different evolutionary entities. They analysed phenotypic and genetic differences, e.g. in the skin colour pattern and in meristic characters such as the number of scales in the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

, which distinguish the two species. They applied a coalescent-based approach to mtDNA phylogeny and evaluated the degree of historical admixture, testing overall genetic differences from

amplified fragment length polymorphism AFLP-PCR or just AFLP is a PCR-based tool used in genetics research, DNA fingerprinting, and in the practice of genetic engineering. Developed in the early 1990s by KeyGene, AFLP uses restriction enzymes to digest genomic DNA, followed by ligati ...

(AFLP). The Italian southern pike turned out distinct from the northern pike, whose range extends from central and northern Europe across Asia to North America. The authors recommend stopping the stocking of pike in southern Europe using northern pike from other European countries, as this could greatly impact the survival of this newly discovered species in its native range.

References

External links

''Esox cisalpinus''
FishBase {{Taxonbar, from=Q991324 Esox Freshwater fish of Europe Fish described in 2011 it:Esox lucius#Specie affini