Caerulonettion Temporal range: Early Miocene–Middle Miocene PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Genus:	†Caerulonettion Zelenkov, 2023
Species:	†C. natator
Binomial name
†Caerulonettion natator (Zelenkov, 2023)
Synonyms
Anas natator (Milne-Edwards, 1867) Querquedula natator (Brodkorb, 1964) Dendrochen natator (Cheneval, 1983) Mionetta natator (Livezey & Martin, 1988)

Caerulonettion (meaning "teal teal") is an extinct genus of anatid birds from the Miocene Epoch of Europe. The genus contains a single species, C. natator, known from various limb and girdle bones. The Caerulonettion fossil material was originally assigned to various other anatid genera before being recognized as a distinct genus.

Fossil material assigned to Caerulonettion has been found in Early Miocene rocks of France and the Czech Republic, as well as early Middle Miocene rocks of Southern Germany. The lectotype specimen, MNHN Av-6428, consists of a left ulna found in the Saint-Gérand-le-Puy fossil locality of France. Additional bones known from nearby localities include right coracoids, humeri, ulnae, carpometacarpi, femora, and tibiotarsi. Partial left coracoids from the Sandelshausen locality of Germany and the Dolniche locality of Czech Republic have also been assigned to Caerulonettion.^[1]

Before being assigned to its own distinct genus, the fossil material was first considered to be a species of Anas in 1867, Querquedula in 1964, Dendrochen in 1983, and Mionetta from 1988 to 2023.^[1]

In 2023, Nikita Zelenkov described Caerulonettion natator as a new combination for the extinct duck "Mionetta" natator based on these fossil remains. The generic name, "Caerulonettion", combines the Latin word caeruleus, the name of a teal or azure color, and Nettion, an obsolete genus name for extant teals, which is derived from the Greek "nēttion", meaning "small duck".^[1][2] The specific name, "natator", means "swimmer" in Latin.^[3]

The preserved coracoids of Caerulonettion are proportionally and structurally similar to those seen in the extant Malacorhynchus (pink-eared duck) of Australia. However, since Caerulonettion is only known from limited fossil material, it is not known if the two genera are phylogenetically close. Zelenkov (2023) interpreted the similar coracoid structure as being a plesiomorphic trait. The coracoids of the Pinpanetta tedfordi, one of the oldest anatids, are also generally similar. Zelenkov further suggested that Caerulonettion represents a more derived anatid than Mionetta, and a possible ancestor of the Middle Miocene Mioquerquedula.^[1]

v t e Genera of waterfowl and their extinct allies
Kingdom: Animalia Phylum: Chordata Class: Aves Clade: Neognathae Superorder: Galloanserae Avemetatarsalia see Avemetatarsalia Theropoda see Theropoda Maniraptora see Maniraptora Anserimorphae see below↓
Anserimorphae Anserimorphae †Conflicto †Gastornis? †Dromornithidae? †Pelagornithidae? †Vegaviidae? †Presbyornithidae Bumbalavis Headonornis? Murgonornis Presbyornis Proherodius Telmabates Teviornis Wilaru †Anachronornithidae Anachronornis Danielsavis? Anseriformes sensu stricto †Agnopterus? †Eonessa †"Headonornis"? †Naranbulagornis †Paakniwatavis †Palaeopapia †Peioa †Petropluvialis? †Proherodius? †Wunketru Anhimae †Chaunoides Anhimidae Anhima †Chainkanas Chauna Anseres Anseranatoidea †Anatalavis? Anseranatidae Anseranas †Anserpica †Eoanseranas Anatoidea †Paranyrocidae Paranyroca Anatidae See below ↓
Anatidae Anatidae †Aldabranas? †Allgoviachen †Ankonetta? †Awengkere †Bambolinetta? †Caerulonettion †Cayaoa? †Chelychelynechen? †Cousteauvia †Eonerornis? †Eutelornis? †Garganornis? †Helonetta? †Heteroanser? †Lavanttalornis †Loxornis? †Mioquerquedula? †Nogusunna? †Notochen †Proanser? †Protomelanitta? †Ptaiochen? †Selenonetta †Sharganetta? †Sinanas? †Tagayanetta †Talpanas? †Teleornis? †Thambetochen? †Wasonaka? †Romainvillinae Paracygnopterus Romainvillia Saintandrea Dendrocygninae Dendrocygna Thalassornis †Dendrocheninae Dendrochen Manuherikia Mionetta Stictonettinae Stictonetta Anserinae †Afrocygnus †Annakacygna Anser †Anserobranta †Asiavis †Bonibernicla Branta Cereopsis †"Chenopis" †Cnemiornis Coscoroba †Cygnavus Cygnus †Cygnopterus †Eremochen †Megalodytes †Paracygnus †Presbychen Tadorninae Alopochen †Australotadorna †Brantadorna Cairina †Centrornis Chloephaga Cyanochen Hymenolaimus †Kaikenia Merganetta †Miotadorna †Nannonetta Neochen Plectropterus †Pleistoanser Radjah Sarkidiornis Tachyeres Tadorna †Tamtamia Anatinae Aix Amazonetta †Anabernicula Asarcornis Biziura Callonetta †Chenoanas? Chenonetta †Dunstanetta †Eoneornis? †Lavadytis Lophonetta Malacorhynchus Marmaronetta Netta Nettapus †Pinpanetta Pteronetta †?Rhodonessa Salvadorina Speculanas Oxyurini Heteronetta Nomonyx Oxyura †Tirarinetta Mergini Bucephala †Camptorhynchus †Chendytes Clangula Histrionicus Lophodytes Melanitta Mergellus Mergus Polysticta †Shiriyanetta Somateria Anatini Anas Mareca †Matanas Sibirionetta Spatula Aythyini Aythya