In the past, it was considered a subspecies of the common (or European) carp, often under the scientific name C. carpio haematopterus (a synonym), but the two differ in genetics[3][4] and meristics, leading recent authorities to recognize them as separate species.[1][2] Although earlier studies also have found minor differences between northern ("haematopterus") and southern ("viridiviolaceus") populations in Eastern Asia in both meristics[5] and genetics,[3] later studies have found that they are not monophyletic.[6] However, any phylogenetic structure is difficult to establish because of widespread translocations of carp between different regions.[6] The parent species of the domesticated koi carp is an East Asian carp, possibly C. rubrofuscus (not C. carpio).[7][8]
^ abZhou, J., Wu, Q., Wang, Z. and Ye, Y. (2004). Molecular Phylogenetics of Three Subspecies of Common carp Cyprinus Carpio, based on sequence analysis of cytochrome b and control region of mtDNA. Journal of Zoological Systematics and Evolutionary Research 42(4): 266–269.
^Xu, P., Zhang, X., Wang, X., et al. (2014). Genome sequence and genetic diversity of the common carp, Cyprinus carpio. Nature Genetics 46: 1212–1219 doi:10.1038/ng.3098
^Kirpitchnikov, V.S., and Billard, R. (1999). Genetics and Breeding of Common Carp. p. 5. INRA. ISBN978-2-7380-0869-5
^ abWang, C., Liu, H., Liu, Z., Wang, J., Zou, J., and Li, X. (2010). Mitochondrial genetic diversity and gene flow of common carp from main river drainages in China. Freshwater Biology 55(9): 1905–1915.