Editing Narwhal (section)

=== Evolution ===

Results of a genetic study reveal that [[porpoise]]s and monodontids are closely related, forming a separate [[clade]] which diverged from other [[Delphinoidea|dolphin]]s about 11 [[million years ago]] (mya).<ref>{{Cite journal |last1=Waddell |first1=Victor G. |last2=Milinkovitch |first2=Michel C. |last3=Bérubé |first3=Martine |last4=Stanhope |first4=Michael J. |date=1 May 2000 |title=Molecular phylogenetic examination of the ''Delphinoidea'' trichotomy: congruent evidence from three nuclear loci indicates that porpoises (''Phocoenidae'') share a more recent common ancestry with white whales (''Monodontidae'') than they do with true dolphins (''Delphinidae'') |url=https://www.sciencedirect.com/science/article/pii/S1055790399907510 |journal=Molecular Phylogenetics and Evolution |volume=15 |issue=2 |pages=314–318 |bibcode=2000MolPE..15..314W |doi=10.1006/mpev.1999.0751 |issn=1055-7903 |pmid=10837160|url-access=subscription }}</ref> A 2018 molecular analysis of monodontid fossils indicates that they separated from Phocoenidae (porpoises) around 10.82 to 20.12 mya, and they are considered to be [[sister taxon|sister taxa]].<ref>{{Cite journal |last1=Racicot |first1=Rachel A. |last2=Darroch |first2=Simon A. F. |last3=Kohno |first3=Naoki |date=October 2018 |title=Neuroanatomy and inner ear labyrinths of the narwhal, ''Monodon monoceros'', and beluga, ''Delphinapterus leucas'' (Cetacea: ''Monodontidae'') |journal=Journal of Anatomy |language=en |volume=233 |issue=4 |pages=421–439 |doi=10.1111/joa.12862 |issn=0021-8782 |pmc=6131972 |pmid=30033539}}</ref> A later [[phylogenetic analysis|phylogenetic study]] conducted in 2020 suggested that the narwhal split from the beluga whale around 4.98 mya, based on data from [[mitochondrial DNA]].<ref>{{Cite journal |last1=Louis |first1=Marie |last2=Skovrind |first2=Mikkel |last3=Samaniego Castruita |first3=Jose Alfredo |last4=Garilao |first4=Cristina |last5=Kaschner |first5=Kristin |last6=Gopalakrishnan |first6=Shyam |last7=Haile |first7=James S. |last8=Lydersen |first8=Christian |last9=Kovacs |first9=Kit M. |last10=Garde |first10=Eva |last11=Heide-Jørgensen |first11=Mads Peter |last12=Postma |first12=Lianne |last13=Ferguson |first13=Steven H. |last14=Willerslev |first14=Eske |last15=Lorenzen |first15=Eline D. |date=29 April 2020 |title=Influence of past climate change on phylogeography and demographic history of narwhals (''Monodon monoceros'') |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=287 |issue=1925 |pages=20192964 |doi=10.1098/rspb.2019.2964 |issn=0962-8452 |pmc=7211449 |pmid=32315590}}</ref>

The fossil species ''[[Casatia thermophila]]'' of [[early Pliocene]] central [[Italy]] was described as a possible narwhal ancestor when it was discovered in 2019. ''[[Bohaskaia]]'', ''[[Denebola brachycephala|Denebola]]'' and ''[[Haborodelphis]]'' are other extinct genera known from the [[Pliocene]] of the United States.<ref name=":14" /><ref name=":2" /><ref>{{Cite journal |last1=Ichishima |first1=Hiroto |last2=Furusawa |first2=Hitoshi |last3=Tachibana |first3=Makino |last4=Kimura |first4=Masaichi |date=May 2019 |editor-last=Hautier |editor-first=Lionel |title=First monodontid cetacean (Odontoceti, Delphinoidea) from the early Pliocene of the north-western Pacific Ocean |url=https://onlinelibrary.wiley.com/doi/10.1002/spp2.1244 |journal=Papers in Palaeontology |language=en |volume=5 |issue=2 |pages=323–342 |bibcode=2019PPal....5..323I |doi=10.1002/spp2.1244 |issn=2056-2799|url-access=subscription }}</ref> Fossil evidence shows that prehistoric monodontids lived in tropical waters. They may have migrated to Arctic and subarctic waters in response to changes in the marine food chain.<ref name=":14" /><ref name=":2">{{Cite journal |last1=Vélez-Juarbe |first1=Jorge |last2=Pyenson |first2=Nicholas D. |date=1 March 2012 |title=''Bohaskaia monodontoides'', a new monodontid (Cetacea, ''Odontoceti'', ''Delphinoidea'') from the Pliocene of the western North Atlantic Ocean |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2012.641705 |journal=Journal of Vertebrate Paleontology |language=en |volume=32 |issue=2 |pages=476–484 |bibcode=2012JVPal..32..476V |doi=10.1080/02724634.2012.641705 |issn=0272-4634 |s2cid=55606151|url-access=subscription }}</ref>

The following [[phylogenetic tree]] is based on a 2019 study of the family Monodontidae.<ref name=":14">{{Cite journal |last1=Bianucci |first1=Giovanni |last2=Pesci |first2=Fabio |last3=Collareta |first3=Alberto |last4=Tinelli |first4=Chiara |date=4 May 2019 |title=A new ''Monodontidae'' (Cetacea, ''Delphinoidea'') from the lower Pliocene of Italy supports a warm-water origin for narwhals and white whales |url=https://www.tandfonline.com/doi/full/10.1080/02724634.2019.1645148 |journal=Journal of Vertebrate Paleontology |language=en |volume=39 |issue=3 |pages=e1645148 |bibcode=2019JVPal..39E5148B |doi=10.1080/02724634.2019.1645148 |issn=0272-4634 |s2cid=202018525 |access-date=21 January 2024 |hdl-access=free |hdl=11568/1022436}}</ref>

{{clade
|1={{extinct}}''[[Kentriodon|Kentriodon pernix]]''
   |2={{clade
      |1={{clade
         |1=''[[Tursiops truncatus]]'' (Common bottlenose dolphin)
         |2=''[[Phocoena phocoena]]'' (Harbour porpoise)
         }}
      |label2=[[Monodontidae]]
      |2={{clade
         |1={{extinct}}''[[Haborodelphis|Haborodelphis japonicus]]''
         |2={{clade
            |1={{extinct}}''[[Denebola brachycephala]]''
            |2={{clade
               |1={{clade
                  |1={{extinct}}''[[Bohaskaia monodontoides]]''
                  |2='''''Monodon monoceros'''''
                  }}
               |2={{clade
                  |1={{clade
                     |1={{extinct}}''[[Casatia thermophila]]''
                     |2=[[Museum of Natural Sciences|IRSNB]] M 1922
                     }}
                  |2=''[[Delphinapterus leucas]]'' (Beluga whale)
                  }}
               }}
            }}
         }}
      }}
   }}