Procaimanoidea Explained

Procaimanoidea ("Before Caiman-forms") is an extinct genus of alligatorid from the Eocene of North America. It was named posthumously in 1946 by Charles W. Gilmore; the type species is P. utahensis, from the Uintan (middle Eocene) of Utah. It is based on USNM 15996, a nearly complete skull and partial left hind leg.^[1] A second species, P. kayi, was named in 1941 by C.C. Mook as a species of Hassiacosuchus, for remains from the Bridgerian (early Eocene) of Wyoming.^[2] It was reassigned to Procaimanoidea in 1967 by Wassersug and Hecht.^[3]

Description

Procaimanoidea was a small alligatorid, and slightly heterodont, the last four teeth on each side of the jaws having blunt tips.^[1]

Phylogeny

Recent studies have consistently resolved Procaimanoidea 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]

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

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

External links

• Procaimanoidea in the Paleobiology Database

Notes and References

1. Gilmore . Charles W. . Charles W. Gilmore . A new crocodilian from the Eocene of Utah . Journal of Paleontology . 20 . 1 . 62–67.
2. Mook . C.C. . 1941 . A new crocodilian, Hassiacosuchus kayi, from the Bridger Eocene beds of Wyoming . Annals of the Carnegie Museum . 28 . 207–220. 10.5962/p.330789 . 251510549 . free .
3. Wassersug . R.J. . Hecht, M.K. . 1967 . The status of the crocodylid genera Procaimanoidea and Hassiacosuchus in the New World . Herpetologica . 23 . 1 . 30–34.
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 . 10.1098/rspb.2018.0843 . 30135152 . 6125902 .
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 . 10.7717/peerj.7562 . 31720094 . 6839522 . free .
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 . e1767638 . 10.1080/02724634.2020.1767638 . 2020JVPal..40E7638C . free .