Suskityrannus hazelae is a small tyrannosauroid from the Moreno Hill Formation of New Mexico, described in 2019 from two partial skeletons. Its age, about 92 million years, places it in a poorly sampled interval between older small tyrannosauroids and the later giant tyrannosaurids of North America. The fossils preserve a combination of skull and limb anatomy that helps bridge that record, but they do not turn the species into a direct ancestor of Tyrannosaurus. One particularly informative feature is the arrangement of bones in the foot.
Quick facts
| Species | Suskityrannus hazelae Nesbitt et al., 2019 |
|---|---|
| Age | Middle Turonian, approximately 92 million years ago |
| Region | Moreno Hill Formation, Zuni Basin, New Mexico, USA |
| Type material | Two partial skeletons, including skull and limb bones |
| Group | Tyrannosauroidea, outside the family Tyrannosauridae |
| Diet | Predatory theropod; no meal or prey species is preserved |
| Size | Small-bodied; published estimates are based on incomplete individuals |
Discovery in the Zuni Basin
The first remains were found in 1998 during fieldwork in western New Mexico. Sterling Nesbitt, then a high-school student, helped locate the fossil while working with the Zuni Basin Paleontological Project. A second specimen was recovered from the same broad formation. The material was later prepared and studied as part of a wider effort to document the Moreno Hill fauna, and Nesbitt and colleagues formally named Suskityrannus hazelae in 2019.
The genus name combines the Zuni word suski, meaning coyote, with the Latinised tyrannus, or tyrant. The species name honours Hazel Wolfe, who supported the research and field programme. The name reflects both a local linguistic connection and the small predator's place among tyrannosauroids. It does not mean the animal was a coyote analogue in a detailed ecological sense. The fossils come from the Moreno Hill Formation, part of the Zuni Basin sequence in New Mexico.
Two individuals, not one complete skeleton
The 2019 description documented two individuals with overlapping but incomplete material. The holotype includes a partial skull and associated postcranial bones. The referred specimen preserves additional skull and limb elements, including a femur examined histologically. Together they make Suskityrannus one of the better represented predators from the mid-Cretaceous North American gap, but the bones do not form one complete skeleton. Missing regions have to be reconstructed from related animals.
The specimens are curated in the Arizona Museum of Natural History collection. Their value comes from the combination of anatomy, locality and age rather than from completeness alone. The skull material informs the shape of the head and tyrannosauroid affinities; the legs and feet add evidence about locomotor anatomy. Histology of a long bone can help assess growth stage, but a thin section is only a sample from one bone. It cannot provide a complete growth curve or an exact adult size for the species.
Age and the mid-Cretaceous record
The remains were assigned to the Middle Turonian, approximately 92 million years ago. That date is based on the geological and biostratigraphic framework for the Moreno Hill deposits, not on a calendar-like age measurement of each skeleton. The distinction matters because formations accumulate over time and can contain beds of different ages. The published age places the animal in a period when North American tyrannosauroids were known from a relatively sparse fossil record.
The Moreno Hill fauna includes several dinosaur lineages that were uncommon or absent in the better sampled latest Cretaceous communities. Suskityrannus therefore helps document a changing assemblage rather than a simple ladder leading to one later predator. A fossil occurrence can show that a lineage existed at a particular time and place. It cannot by itself identify the population from which a later species descended, especially when the record contains large geographic and temporal gaps.
The age is especially valuable because the North American record between older small tyrannosauroids and later tyrannosaurids is uneven. Suskityrannus does not close that interval by itself, but it provides a named taxon with skull and postcranial bones rather than a handful of isolated teeth. Its placement can be tested with later finds, and its characters help compare the timing of changes in the foot and skull. A gap in sampling is a property of the fossil record; it is not evidence that only one intermediate animal existed.
The foot and a cautious account of movement
The most discussed feature is an arctometatarsalian foot, in which the upper part of the middle metatarsal is pinched between neighbouring metatarsals. The condition appears in several later tyrannosauroids and is present in Suskityrannus at a comparatively small body size. The describing team identified it as an early occurrence of this configuration in tyrannosauroids. It is an anatomical observation from preserved bones and a useful point in reconstructing how the group changed through time.
The foot's structure has been associated with locomotor performance in predatory dinosaurs, and the original study interpreted it as evidence that enhanced cursorial capacity arose before giant size. That is a functional inference from anatomy. No trackway can be securely assigned to the two Suskityrannus skeletons, and the bones do not reveal a measured top speed, hunting tactic or distance travelled. A robust account can say the foot is consistent with a more derived running-related arrangement, while leaving exact performance unknown.
Skull, teeth and body proportions
The known skull elements show a theropod predator with a deepening tyrannosauroid profile, but the skull is not complete. Teeth and jaw fragments can be compared with other theropods, while missing parts of the snout and braincase should not be drawn as if directly preserved. The limb bones show a bipedal animal. Its total length and mass estimates depend on scaling missing portions against better represented tyrannosauroids and therefore carry more uncertainty than measurements of the surviving bones.
The taxonomic analysis placed Suskityrannus among Tyrannosauroidea but outside Tyrannosauridae. It shared a number of derived features with later members of the group, yet lacked the full character combination used to diagnose the later family. Phylogenetic position describes a hypothesis about branching relationships based on scored anatomical features. It does not mean that Suskityrannus was a direct ancestor of Tyrannosaurus, nor that evolution proceeded toward a predetermined giant form.
The Moreno Hill setting also makes the taxon useful beyond its position on a family tree. Its fossils occur in a community that includes other dinosaur groups, among them Zuniceratops and the therizinosaur Nothronychus. These associations show that the region supported a varied fauna during the Turonian. They do not establish that all named animals lived at one exact moment or interacted directly, because a formation can combine deposits laid down across time and different habitats. The tyrannosauroid record is a part of that community, not a complete census of every predator present.
Feathers, diet and life appearance
The described specimens preserve bones, not feathers or skin. Some other tyrannosauroids preserve filamentous integument, and those discoveries make a feathered appearance plausible for parts of the wider group. They do not directly show that Suskityrannus carried feathers. Reconstructions often depict a fuzzy or feathered animal because it is visually compelling and phylogenetically plausible, but the image must remain an informed hypothesis rather than a fossil observation.
As a small theropod tyrannosauroid, Suskityrannus was a predator, but the fossils do not identify a stomach meal or a preferred prey species. Its habitat included the environments represented by the Moreno Hill deposits, where other dinosaurs and animals lived. A list of co-occurring fossils does not prove that every species met the predator or formed one stable community at the same time. Claims about pack hunting, parental care, courtship and calls are not established by the known bones.
The name hazelae honours Hazel Wolfe, whose support was connected with the research programme that worked in the Zuni Basin. The field history links the specimen to a long-running regional project rather than a single isolated discovery. That context is useful for understanding how the fossils were recovered and studied, but it does not alter the anatomical diagnosis. The two individuals remain the direct evidence, and additional associated material would be needed to test details of the species' growth, variation and complete appearance.
Why the species matters
Suskityrannus is valuable because it adds a comparatively informative tyrannosauroid to an interval with few well-preserved North American predators. Its foot shows that an important anatomical configuration preceded the enormous bodies of the latest Cretaceous tyrannosaurids. Its age and anatomy help constrain when some features appeared, even though the precise path between individual taxa remains incomplete.
Further discoveries could clarify how the skull and limbs varied with growth and whether the two known individuals represent a broader population pattern. Better dated localities would sharpen the chronology, while associated skeletons could improve estimates of body proportions. Until then, the evidence supports a small-bodied, mid-Cretaceous tyrannosauroid with a distinctive foot, not an exact speed or direct ancestor claim. Compare it with later tyrannosauroids in the dinosaur catalogue without treating a family-tree diagram as a fossil chain.
Frequently asked questions
What does the name Suskityrannus mean?
The genus name combines suski, a Zuni word for coyote, with tyrannus, ‘tyrant’. The name recognises the animal's small predator profile and the local Zuni language; it does not imply a direct resemblance or relationship to modern coyotes.
Where was Suskityrannus found?
The two described specimens come from the Moreno Hill Formation in the Zuni Basin of western New Mexico. The formation preserves a mid-Cretaceous dinosaur community that helps fill a gap in the North American record.
Was Suskityrannus a tyrannosaurid?
No. The 2019 study placed it within Tyrannosauroidea but outside Tyrannosauridae. It shared some features with later tyrannosaurids, including an arctometatarsalian foot, but it was not Tyrannosaurus or a member of that later family.
Did Suskityrannus have feathers?
No feathers or skin impressions have been reported for the described specimens. Filaments occur in some other tyrannosauroids, but that comparison cannot establish the covering of Suskityrannus itself.