Paralligator

Paralligator Temporal range: Late Cretaceous, ~96–70  Ma PreꞒ Ꞓ O S D C P T J K Pg N
P. gradilifrons and P. major skulls from the Bayan Shireh Formation
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Clade:	Neosuchia
Family:	† Paralligatoridae
Genus:	† Paralligator
Type species
†Paralligator gradilifrons Konzhukova, 1954
Other species
†P. ancestralisEfimov, 1981 †P. majorEfimov, 1981
Synonyms
Shamosuchus tersus Efimov, 1983 Shamosuchus ulanicus Efimov, 1983 Shamosuchus ulgicus Efimov, 1981

Paralligator is an extinct genus of neosuchian crocodylomorph that lived during the Late Cretaceous (Cenomanian-Maastrichtian) period in what is now the Bayan Shireh and Nemegt formations of Mongolia, approximately 96 million to 70 million years ago.

Description

P. gradilifrons reached up to 4 m (13 ft) in length. ^{[1] [2]} The cerebral hemispheres are the widest portions of the endocast of Paralligator; they are approximately 2.5 times wider than the olfactory tract and about 1.5 times wider than the midbrain and the portion corresponding to the medulla oblongata. The olfactory complex is as long as the remainder of the endocast and is thus highly anteroposteriorly elongated. The olfactory tract of Paralligator is transversally narrow and highly elongated, and it expands posteriorly into the cerebral hemispheres and anteriorly into the olfactory bulbs, which are paired and are divided by the mesethmoid facet, diverging anteriorly at an angle of approximately 25°–30°. Posterior to the cerebral hemispheres lies the mesencephalic portion of the endocast, which is notably constricted when observed from a dorsal view. Posterior to the mesencephalic portion of the endocast lies the anterior portion of the rhombencephalon, consisting of the pons and cerebellum; this section is notably laterally and dorsoventrally expanded. The flocculus is not developed. The medulla oblongata is wider lateromedially than it is deep. ^[3]

Taxonomy

Life restoration of P. gradilifrons

Two species are recognized: ^[4]

• Paralligator gradilifrons Konzhukova, 1954 ^[5]
• Paralligator major Efimov, 1981 ^[6]

Misassigned species

"Paralligator" sungaricus, described from the Early Cretaceous Nenjiang Formation of Jilin Province, China, is based on postcranial remains consisting of a few presacral vertebrae, dorsal osteoderms, a partial left femur, and the proximal part of a left tibia and fibula. ^{[7] [8]} However, the type material is too fragmentary to be considered diagnostic, and the species is a nomen dubium . ^[4] Turner (2015) also referred P. ancestralis a junior subjective synonym of P. gradilifrons. ^[4]

References

1. Storrs, G. W.; Efimov, M. B. (2000). "Mesozoic crocodyliforms of north-central Eurasia". In Michael J. Benton; Mikhail A. Shishkin; David M. Unwin; Evgenii N. Kurochkin (eds.). The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press. pp. 402–419.
2. Turner, Alan H. (25 February 2015). "A Review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia". PLOS ONE . 10 (2) e0118116. Bibcode:2015PLoSO..1018116T. doi: 10.1371/journal.pone.0118116 . ISSN   1932-6203. PMC   4340866 . PMID   25714338.
3. Kuzmin, Ivan T.; Sichinava, Ekaterina A.; Mazur, Evgeniia V.; Gombolevskiy, Victor A.; Sennikov, Andrey G.; Skutschas, Pavel P. (28 December 2024). "Neurocranial anatomy of Paralligator (Neosuchia: Paralligatoridae) from the Upper Cretaceous of Mongolia". Zoological Journal of the Linnean Society . 203 (1). doi:10.1093/zoolinnean/zlae177. ISSN   0024-4082 . Retrieved 1 November 2025– via Oxford Academic.
4. Turner, A. H. (2015). "A review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia". PLOS ONE. 10 (2) e0118116. Bibcode:2015PLoSO..1018116T. doi: 10.1371/journal.pone.0118116 . PMC   4340866 . PMID   25714338.
5. Konzhukova ED (1954) [New fossil crocodilian from Mongolia]. Trudy Paleontologicheskogo Instituta ANSSSR 48: 171–194.
6. Efimov MB (1981) New paralligatorids from the Upper Cretaceous of Mongolia. Trudy Sovmestnoi Sovetsko-Mongol'skoi Paleontologicheskoi Ekspeditsii 15: 26–28.
7. Sun, A.-L. (1958). "A new species of Paralligator from Sungarian Plain". Vertebrata PalAsiatica . 2 (4): 277–280.
8. Wu, X.-C.; Cheng, Z.-W.; Russell, A. P. (2001). "Cranial anatomy of a new crocodyliform (Archosauria: Crocodylomorpha) from the Lower Cretaceous of Song-Liao Plain, northeastern China". Canadian Journal of Earth Sciences . 38 (12): 1653–1663. doi:10.1139/cjes-38-12-1653.