Diablophis gilmorei is a Late Jurassic squamate from the Morrison Formation of Colorado, known from fragments of jaws and vertebrae. In 2015, CT-based comparisons separated it from the British genus Parviraptor and placed it near the base of the snake lineage. A more complete relative described in 2025 established the family Parviraptoridae, but that study did not include Diablophis in its tree analyses because the American fossils remain too incomplete. Its snake-like anatomy is real; its exact branch is still a question. The fossil belongs alongside other early squamates in the ancient lizard and snake catalogue.
Quick facts
| Scientific name | Diablophis gilmorei (Evans, 1996) |
|---|---|
| Former name | Parviraptor gilmorei |
| Age | Late Jurassic, Kimmeridgian |
| Formation | Morrison Formation, Brushy Basin Member |
| Locality | Fruita paleontological area, Colorado, USA |
| Type material | LACM 4684/140572, fragmentary maxilla, dentary and vertebrae |
| Current group | Parviraptoridae |
| Snake relationship | Possible stem-snake affinity, but not directly tested in the 2025 analyses |
What can the fossils tell us?
A new genus name clarifies the taxon; it does not settle its position among squamates.
No complete skull or jaw joint shows the full feeding mechanism.
The bones are incomplete and not all are preserved in association with the jaws.
It omitted Diablophis from its phylogenetic analyses because its remains are too incomplete.
From Parviraptor to a separate name
Susan Evans described the American material in 1996 as Parviraptor gilmorei, comparing it with the small British squamate Parviraptor. Michael Caldwell, Randall Nydam, Alessandro Palci and Sebastián Apesteguía reassessed the remains in 2015 using new comparisons and CT information. They named the species Diablophis gilmorei, retaining the species epithet in a different genus.
The name points to the Devil’s Canyon area near the Fruita locality. The fossils come from the Brushy Basin Member of the Morrison Formation in western Colorado. Their late Jurassic age places them in the Kimmeridgian, among a vertebrate fauna better known for dinosaurs but also containing small mammals, lizards and other reptiles.
Fragments, not a complete snake skeleton
The main specimen, LACM 4684/140572, includes broken portions of a right maxilla and dentary, together with vertebral material. Additional pieces have been referred to the species. They are not all articulated into one skeleton, so an article or illustration should not quietly assemble them into a complete skull, backbone and body.
The jaw fragments preserve recurved marginal teeth and a long toothed section behind the front of the upper jaw. The tooth crowns have cutting edges, a combination compatible with taking animal prey. The fossil does not preserve prey, stomach contents or a complete jaw joint. It therefore cannot establish the size of prey or the precise mechanics of swallowing.
What the 2015 snake hypothesis used
The 2015 study treated Diablophis as one of several very early snake candidates. Recurved teeth, jaw features and vertebral characters contributed to its placement near the snake stem. In that interpretation, the fossil showed that some traits associated with snake feeding could appear before the fully specialised anatomy of living snakes.
The broader 2015 paper extended the record of candidate snakes back into the Jurassic. Its trees grouped several fragmentary forms, but the answer depended on which bones could be assigned to each taxon and how the character matrix was built. At the time, the available material did not preserve the whole anatomical combination needed to test every alternative.
The 2025 revision narrows what can be claimed
In 2025, Roger Benson and colleagues described Breugnathair elgolensis, a more complete Middle Jurassic squamate from Scotland, and formally established Parviraptoridae. Their family includes Parviraptor, Diablophis, Portugalophis and the new genus. The newly described skeleton combines snake-like teeth with a limbed, lizard-like body and older skull features.
The authors recovered parviraptorids in different positions across their analyses: as stem squamates, near the snake stem, or near the common branch of anguimorphs and snakes. They did not add the more incomplete Diablophis to those analyses pending better material. Thus the 2025 paper supports its membership in a distinct family but does not independently confirm that Diablophis was a snake or resolve the family’s deeper placement.
What a reconstruction must leave open
The known remains support a small-bodied squamate with recurved teeth. They do not give a secure total length, limb pattern, scale covering or colour. Because limb bones are not documented for the type, a full snake-like body in a life restoration would be a hypothesis, not a view directly recovered from the fossils.
Fruita’s Morrison deposits accumulated in a continental landscape with rivers and seasonal water bodies. Other animals found in the same formation describe the ecosystem, but they are not proof of what Diablophis ate. The most useful comparison is with other early snake candidates, including the Late Cretaceous Coniophis and the Jurassic Parviraptoridae, while keeping each taxon’s own evidence separate.
The boundary between a snake and a close relative matters here. Diablophis may preserve an early part of snake evolution, but the defensible description is narrower: a fragmentary Jurassic parviraptorid with snake-like jaws and unresolved deeper affinities. Compare its incomplete record with the later fossil Coniophis, while keeping each taxon’s evidence separate.
Frequently asked questions
Was Diablophis first named Parviraptor?
Yes. It was described as Parviraptor gilmorei in 1996 and reassigned to the new genus Diablophis in 2015.
Was it a snake?
A 2015 analysis placed it near the snake stem. A 2025 study included it in Parviraptoridae but omitted it from phylogenetic analyses because the fossils are too incomplete.
What fossils are known?
The record includes fragments of the upper and lower jaws and vertebrae, not a complete skull or skeleton.
Where did Diablophis live?
Its fossils come from the Brushy Basin Member of the Morrison Formation near Fruita, Colorado, during the Late Jurassic.