Arambourgia

Not to be confused with Arambourgiania.

Arambourgia Temporal range: Late Eocene, 37.8–33.9 Ma[1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Family:	Alligatoridae
Subfamily:	Alligatorinae
Genus:	†Arambourgia Kälin, 1940
Type species
†Allognathosuchus gaudryi de Stefano, 1905

Arambourgia is an extinct monotypic genus of alligatorine crocodylian from Europe. It was named in 1905 as Allognathosuchus gaudryi. It was made a separate genus Arambourgia in 1940. This was synonymized with Allognathosuchus haupti in 1990^[2] (now known as Hassiacosuchus haupti), but later reassigned as its own genus once again in 2004.^[3] Arambourgia was likely to have been part of an early dispersal event of alligatorines from North America to Europe during the Eocene epoch. Arambourgia had non-serrated teeth and a deep orienirostral snout, unlike the flatter snouts of most other alligatorids.

Recent studies have consistently resolved Arambourgia as a member of Alligatorinae, although its relative placement is disputed, as shown by the cladograms below.^[4][5][6]

Cladogram from 2018 Bona et al. study:^[4]

Alligatorinae

Ceratosuchus burdoshi† Allognathosuchus polyodon† Allognathosuchus wartheni† Navajosuchus mooki† Arambourgia gaudryi† Procaimanoidea kayi† Procaimanoidea utahensis† Wannaganosuchus brachymanus† Alligator prenasalis† Alligator mcgrewi† Alligator olseni† Alligator sinensis Chinese alligator Culebrasuchus mesoamericanus† Alligator mississippiensis American alligator Alligator mefferdi† Alligator thomsoni†

Cladogram from 2019 Massonne et al. study:^[5]

Alligatorinae	Alligator prenasalis† Alligator mcgrewi† Alligator olseni† Alligator sinensis Chinese alligator Alligator thomsoni† Alligator mefferdi† Alligator mississippiensis American alligator Procaimanoidea utahensis† Procaimanoidea kayi† Arambourgia gaudryi† Hassiacosuchus haupti† Wannaganosuchus brachymanus† Allognathosuchus wartheni† Allognathosuchus polyodon†

Cladogram from 2020 Cossette & Brochu study:^[6]

Alligatorinae	Ceratosuchus burdoshi† Hassiacosuchus haupti† Navajosuchus mooki† Allognathosuchus polyodon† Alligator mcgrewi† Alligator prenasalis† Wannaganosuchus brachymanus† Arambourgia gaudryi† Procaimanoidea kayi† Procaimanoidea utahensis† Alligator olseni† Alligator sinensis Chinese alligator Alligator mississippiensis American alligator Alligator mefferdi† Alligator thomsoni†

Palaeoecology

Based on its unusual anatomy and it having been found in karstic settings, A. gaudryi occupied an ecological niche analogous to present-day juvenile and dwarf crocodylians.^[7]

References

1. Rio, Jonathan P.; Mannion, Philip D. (6 September 2021). "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem". PeerJ. 9: e12094. doi:10.7717/peerj.12094. PMC 8428266. PMID 34567843.
2. Rauhe, M. (1990). "Habit-Habitus-Wechselbeziehung von Allognathosuchus gaudryi Stefano 1905 (=Allognathosuchus haupti Weitzel 1935)". Geologisches Jahrbuch Hessen. 118: 53–61.
3. Brochu, Christopher A. (2004). "Alligatorine phylogeny and the status of Allognathosuchus Mook, 1921". Journal of Vertebrate Paleontology. 24 (4): 857–873. doi:10.1671/0272-4634(2004)024[0857:APATSO]2.0.CO;2. S2CID 85050852.
4. Paula Bona; Martín D. Ezcurra; Francisco Barrios; María V. Fernandez Blanco (2018). "A new Palaeocene crocodylian from southern Argentina sheds light on the early history of caimanines". Proceedings of the Royal Society B: Biological Sciences. 285 (1885): 20180843. doi:10.1098/rspb.2018.0843. PMC 6125902. PMID 30135152.
5. Tobias Massonne; Davit Vasilyan; Márton Rabi; Madelaine Böhme (2019). "A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis". PeerJ. 7: e7562. doi:10.7717/peerj.7562. PMC 6839522. PMID 31720094.
6. Adam P. Cossette; Christopher A. Brochu (2020). "A systematic review of the giant alligatoroid Deinosuchus from the Campanian of North America and its implications for the relationships at the root of Crocodylia". Journal of Vertebrate Paleontology. 40 (1): e1767638. Bibcode:2020JVPal..40E7638C. doi:10.1080/02724634.2020.1767638.
7. Conedera, Davide; Pochat-Cottilloux, Yohan; Rinder, Nicolas; Adrien, Jerôme; Martin, Jeremy E. (4 July 2023). "An anatomical reappraisal of the dwarf crocodylian Arambourgia gaudryi from the Eocene of Quercy (France) using CT data and its implications for the phylogeny and paleoecology of basally branching alligatoroids". Journal of Vertebrate Paleontology. 43 (4). doi:10.1080/02724634.2024.2313612. ISSN 0272-4634. Retrieved 9 December 2024 – via Taylor and Francis Online.