Albertochampsa

Albertochampsa is an extinct genus of alligatorid (possibly a stem-caiman^[1] or a basal alligatorine^[2]) from the Late Cretaceous of Alberta. It was named in 1972 by Bruce Erickson, and the type species is A. langstoni.^[3] It is known from a skull from the Campanian-age Dinosaur Park Formation, where it was rare; Leidyosuchus is the most commonly found crocodilian at the Park. The skull of Albertochampsa was only about 21 cm long (8.3 in).^[4]

Albertochampsa Temporal range: 76.5–75 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Skull at the Yale Peabody Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Order:	Crocodilia
Superfamily:	Alligatoroidea
Family:	Alligatoridae
Genus:	†Albertochampsa Erickson, 1972
Type species
†Albertochampsa langstoni Erickson, 1972

Phylogeny

Albertochampsa is a member of the family Alligatoridae, which includes the extant (living) alligators and caimans, although it is disputed whether Albertochampsa is more closely related to the alligators or the caimans. The below cladogram from a 2018 study shows Albertochampsa as more closely related to the caimans in the subfamily Caimaninae.^[5]

Alligatoridae

Alligatorinae (stem-based group) Caimaninae Stangerochampsa† Albertochampsa† Brachychampsa† Protocaiman† Gnatusuchus† Globidentosuchus† Eocaiman† Notocaiman† Kuttanacaiman† Purussaurus† Mourasuchus† crown group caimans Necrosuchus† Tsoabichi† Paleosuchus trigonatus Smooth-fronted caiman Paleosuchus palpebrosus Cuvier's dwarf caiman Centenariosuchus† Caiman latirostris Broad-snouted caiman Melanosuchus niger Black caiman Caiman yacare Yacare caiman Caiman crocodilus Spectacled caiman Caiman brevirostris† La Venta Caiman† Caiman wannlangstoni† (stem-based group)

(crown group)

The Late Cretaceous taxa Stangerochampsa, Brachychampsa and Albertochampsa have been previously referred to as stem-group caimans,^[5][6] but Walter et al. (2022) recovered them as the basalmost alligatorines based on phylogenetic analysis and claimed that the earliest definitive stem-group caimans are known from the earliest Paleocene.^[7]