''Infernodrakon'' (meaning "dragon from hell") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

azhdarchid Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cre ...

pterosaurs from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Hell Creek Formation The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The Formation (stratigraphy), formation s ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, United States. The genus contains a single species, ''I. hastacollis'', known from a single neck vertebra. Based on comparisons with related azhdarchids, it probably had a wingspan of about .

Discovery and naming

In 2002, a putative immature ''

Tyrannosaurus ''Tyrannosaurus'' () is a genus of large theropod dinosaur. The type species ''Tyrannosaurus rex'' ( meaning 'king' in Latin), often shortened to ''T. rex'' or colloquially t-rex, is one of the best represented theropods. It lived througho ...

'' specimen (BMR P2002.4.1, known as " Jane") was recovered from strata belonging to the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

-age

in Carter County, Montana, United States. Alongside that specimen was the fifth cervical (neck) vertebra of an azhdarchid pterosaur. Catalogued as BMR P2002.2, it was originally assigned to

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

Quetzalcoatlus ''Quetzalcoatlus'' () is a genus of azhdarchid pterosaur that lived during the Maastrichtian age of the Late Cretaceous in North America. The Type (biology), type specimen, recovered in 1971 from the Javelina Formation of Texas, United States, ...

'' sp. In 2014, Alexander Averianov identified the specimen as indeterminate azhdarchid. In 2021, Brian Andres and Wann Langston Jr. classified BMR P2002.2 more broadly as an indeterminate azhdarchiform. In 2025, a team consisting of Henry Thomas, David W. E. Hone, Timothy Gomes, and Joseph E. Peterson re-examined the specimen, determining that it belonged to a novel genus more closely related to '' Arambourgiania philadelphiae'' from Jordan than to ''Quetzalcoatlus''. The authors designated BMR P2002.2 as the holotype of a new pterosaur genus and species, ''Infernodrakon hastacollis''. The generic name, ''Infernodrakon'', combines the

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, a Romance ethnic group related to or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance languag ...

word '' inferno'' (derived from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

infernus Roger Tiegs (born 18 June 1972), better known by his stage name Infernus, is a Norwegian black metal musician and Satanist. He is the sole founding member and chief ideologist of the black metal band Gorgoroth, formed in 1992, in addition to b ...

''), meaning "hell", after the discovery of the holotype in the Hell Creek Formation, with the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

δράκων (''drakon''), meaning "dragon". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''hastacollis'', combines " hasta"—a type of Roman spear—with the Latin root '' collum'', meaning "neck", referencing the extremely long and thin morphology of the preserved vertebra. This name also references the specific epithet of the related '' Azhdarcho lancicollis'', which is derived from the Roman lancea javelin. The intended full binomial name meaning is "spear-necked dragon from Hell".

Description

''Infernodrakon'' is known only from a single neck vertebra measuring long. This bone is extremely elongated and gracile; the ratio of the preserved length to the width at the middle of the centrum ('elongation ratio') is 15.1. The only comparable ratios in azhdarchids are found in quetzalcoatlines, such as 16.3 in ''Quetzalcoatlus lawsoni''. All other azhdarchids for which this ratio can be determined demonstrate ratios below 6. Based on comparisons with related taxa, the maximum straight-line

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

of ''Infernodrakon'' was likely close to . Considering the natural curvature of the wing, the wingspan would have been shorter, at around . As such, it is comparable in size to ''Quetzalcoatlus lawsoni'' () and '' Zhejiangopterus''. Infernodrakon hastacollis

The holotype likely belongs to an adult or a nearly mature individual, since the external surface of the vertebra had a smooth texture unlike the textures of the vertebra in immature pterosaurs. The other feature that distinguishes ''Infernodrakon'' from all other known azhdarchids is the presence of accessory pneumatic foramen ( air sac hole) dorsal to the opening of the posterior neural canal (the rear exit of the

spinal canal In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a pro ...

). In all other azhdarchids, the pneumatic foramen is dorsal or lateral to the opening of the anterior neural canal (the front entrance of the spinal canal), or to both the anterior and posterior neural canal opening. Additionally, the size of the anterior neural canal opening in ''Infernodrakon'' is significantly larger than in other azhdarchids.

Classification

To assess the relationships of ''Infernodrakon'', Thomas et al. (2025) scored it in the comprehensive pterosaur-focused phylogenetic matrix of Pêgas, 2024. They recovered ''Infernodrakon'' as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to '' Arambourgiania'' within the azhdarchid clade Quetzalcoatlinae. These results are displayed in the

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below:

Paleobiology

Though azhdarchid lifestyles have long been debated, more recent analyses suggest that they hunted small terrestrial prey. This model is known as the 'terrestrial stalking' hypothesis. Prey size in azhdarchids would have been limited primarily by torso size, the morphology (and accordingly strength) of their cervical vertebrae, and skull width. ''Infernodrakon'', being a mid-sized azhdarchid with gracile neck vertebrae, would have likely been poorly adapted to the stresses of handling or swallowing large animals. As such, it can be identified as a

mesopredator A mesopredator is a predator that occupies a mid-ranking trophic level in a food web. There is no standard definition of a mesopredator, but mesopredators are usually medium-sized carnivorous or omnivorous animals, such as raccoons, foxes, or ...

, likely consuming small animals including juvenile

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

squamate Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest Order (biology), order of reptiles; most members of which are commonly known as Lizard, lizards, with the group also including Snake, snakes. With over 11,991 species, it i ...

s (lizards and snakes),

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s, and eggs.

References

{{Taxonbar, from1=Q132827067, from2=Q132827078 Azhdarchidae Late Cretaceous pterosaurs of North America Fossils of Montana Cretaceous Montana Maastrichtian genera Hell Creek fauna Fossil taxa described in 2025 Monotypic prehistoric reptile genera