Diplocynodon

Diplocynodon; Temporal range: Paleocene - Middle Miocene, 59.2–13.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	Diplocynodon ratelii
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Superfamily:	Alligatoroidea
Subfamily:	†Diplocynodontinae; Brochu, 1999
Genus:	†Diplocynodon; Pomel, 1847
Species
	†D. dalpiazi Del Favero, 1999; †D. darwini (Ludvig, 1877); †D. deponiae (Frey, Laemmert & Riess, 1987); †D. elavericus Martin, 2010; †D. gervaisi; †D. hantoniensis (Wood, 1846); †D. levantinicum Huene & Nikoloff, 1963; †D. kochi (Venczel & Codrea, 2022); †D. muelleri (Kälin, 1936); †D. ratelii Pomel, 1847 (type); †D. tormis; †D. ungeri (Prangner, 1845);
Synonyms
	Baryphracta Frey, Laemmert & Riess, 1987; Enneodon Pranger, 1845; Hispanochampsa Kälin, 1936; Saurocainus;

Diplocynodon is an extinct genus of alligatoroid crocodilian that lived during the Paleocene to Middle Miocene in Europe. Some species may have reached lengths of 3 metres (9.8 ft),^[7] while others probably did not exceed 1 metre (3.3 ft).^[8] They are almost exclusively found in freshwater environments.^[9] The various species are thought to have been opportunistic aquatic predators.^[10]

In the nineteenth century, D. steineri was named from Styria, Austria and D. styriacus was named from Austria and France. A third Austrian species, Enneodon ungeri, was placed in its own genus. The Austrian and French species of Diplocynodon were synonymized with E. ungeri in 2011, and because the name Diplocynodon has priority over Enneodon, the species is now called D. ungeri.^[11] Other genera have recently been found to be synonymous with Diplocynodon. Hispanochampsa muelleri of Spain was determined to be synonymous with Diplocynodon in 2006,^[5] and Baryphracta deponaie of Germany was confirmed to be synonymous with Diplocynodon in 2012.^[3]

Well preserved specimens have been found in the Messel Pit and the Geiseltal lignite deposit in Germany. Most articulated Diplocynodon specimens from these localities contain gastroliths. In the Eocene epoch, the German sites were either a swampy freshwater lake (Messel Pit) or a peat bog swamp (Geiseltal).

Species

Species
Species	Age	Location	Unit	Notes	Images
D. dalpiazi	Late Rupelian	Italy	Monteviale		D. darwini from Messel pit, Hesse, Germany, 48 million years old Skull of D. hantoniensis Diplocynodon cf. ratelii
D. darwini	Lutetian	Germany	Messel pit	All specimens are from Messel pit of Germany. Synonyms are: D. ebertsi and D. hallense.
D. deponaie^[2]^[3]	Middle Eocene	Germany	Messel pit	Synonyms are: Baryphracta deponaie.
D. elavericus^[12]	Middle Priabonian	France	Domérat	All specimens came from Allier, Massif Central of France.
D. gervaisi	Earliest Rupelian	France	Ronzon	Synonyms are: Saurocainus gervaisi.
D. hantoniensis	Early Priabonian	United Kingdom	Headon Hill Formation	All specimens came from Hordwell, southern England. D. cf. hantoniensis is known from the Oligocene of Dordogne, France.
D. levantinicum^[7]	Oligocene (Chattian)	Bulgaria	Maritsa Formation
D. kochi	Eocene (Priabonian)	Romania	Cluj Limestone Formation
D. muelleri^[5]	Middle Rupelian	Spain	El Talladell	More than 100 are known, all from Lleida Province, Catalonia. Synonyms are: Hispanochampsa muelleri, D. guerini and D. marini.
D. ratelii	Middle Aquitanian* Late Eocene to Early Miocene	France	Saint-Gérand-le-Puy*	D. ratelii is the type species of Diplocynodon. Most of the specimens came from Allier, Massif Central of France. Synonyms are: D. gracile.
D. tormis	Late Bartonian	Spain	Salamanca
D. ungeri^[11]	Middle Miocene	Austria* France	Pannonian Basin* Paris Basin	Synonyms are: Enneodon ungeri, D. steineri, and D. styriacus (see text).

*Locality and/or horizon of the type specimen.

Phylogeny

Diplocynodon is one of the basal-most members of the superfamily Alligatoroidea. Diplocynodon's placement within Alligatoroidea can be shown in the cladogram below, based on a 2018 tip dating study by Lee & Yates that simultaneously used morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data.^[13]