Dineobellator notohesperus was a medium-sized eudromaeosaur from the Naashoibito Member of the Ojo Alamo Formation in New Mexico. A single partial skeleton preserves pieces of the skull, spine and limbs. Its ulna carries possible quill knobs, while hand and tail anatomy suggest strong grip and manoeuvrability without recording behaviour directly.
Quick facts
| Scientific name | Dineobellator notohesperus Jasinski et al., 2020 |
|---|---|
| Group | Theropoda, Dromaeosauridae, Eudromaeosauria |
| Age | Late Cretaceous, Maastrichtian; exact Naashoibito age debated |
| Range | San Juan Basin, New Mexico, United States |
| Length | Approximately 2–3 m |
| Mass | Several tens of kilograms |
| Diet | Carnivorous |
| Species | D. notohesperus |
| Fossil record | One partial skeleton with cranial, vertebral and limb elements |
Abilities written in bone
The arm and hand claws indicate a well-developed gripping apparatus, not a measured grip force.
Small bumps on the ulna support a row of large secondary feathers.
Proximal tail anatomy allowed motion while the longer tail remained a stabiliser.
Healed and unhealed lesions record injury without identifying combat or prey.
Discovery and fossils
The holotype was found in the Bisti/De-na-zin region of the San Juan Basin. Steven Jasinski and colleagues named it in 2020. The name combines a Diné word for Navajo people with Latin bellator, “warrior”; the species refers to the south-west.
Material includes parts of the skull and jaws, vertebrae, ribs, a nearly complete right humerus and ulna, radius fragments, a metacarpal, hand claws and parts of the femur, ankle, foot and tail. No complete skull, pelvis or vertebral column is known.
Size, hands and tail
The incomplete bones support a length around 2–3 metres and a mass of several tens of kilograms. The humerus approaches Deinonychus size but is more slender. Prominent muscle attachments and a large flexor tubercle on a hand claw indicate strong flexion, although no model provides an exact force.
Tail-base vertebrae allowed appreciable mobility. The authors linked this with turning ability, but comparisons with a cheetah are only analogies. A specialised second-toe claw is expected from relationships but is not fully preserved in this animal.
Feathers and injuries
Small bumps on the ulna were interpreted as attachment points for approximately 12–14 secondary feathers. The number is reconstructed because the feathers themselves are absent. They did not make this terrestrial animal capable of flight and may have aided display, brooding or balance.
A rib shows healed damage, while a hand claw carries a lesion without clear healing; other bones also show pathology. These traces demonstrate survival after injury but cannot identify another Dineobellator as the cause.
Classification, age and ecology
The 2020 analysis placed Dineobellator in Velociraptorinae. A 2022 reassessment recovered it outside the three principal eudromaeosaur subgroups, so the broader Eudromaeosauria label is safer. It was one of the last North American dromaeosaurids.
Biostratigraphy has suggested roughly 70–68 million years for the Naashoibito Member, while detrital sanidines provide a maximum depositional age near 66.5 million years. These methods constrain the unit differently. Rivers and floodplains supported dinosaurs, turtles and other vertebrates, but no stomach contents identify Dineobellator’s prey or prove group hunting.
Evidence, inference and reconstruction
| Direct | Partial skull and skeleton, ulna bumps, hand anatomy and pathologies |
|---|---|
| Strong inference | Large arm feathers, carnivory and terrestrial bipedal movement |
| Unresolved | Exact age, subgroup placement and degree of tail agility |
| Unknown | Colour, prey, speed and social behaviour |
Frequently asked questions
When and where did Dineobellator live?
It lived in latest Cretaceous New Mexico. Estimates for the Naashoibito Member range from about 70–68 million years to a maximum depositional age near 66.5 million years.
How large was Dineobellator?
The incomplete skeleton suggests a medium dromaeosaur roughly 2–3 metres long and weighing several tens of kilograms. A precise total is not preserved.
Did Dineobellator have feathers?
Yes, bumps on the ulna support attachment of large secondary feathers. The feathers themselves, their colour and the rest of the body covering are not preserved.
What do Dineobellator’s injuries show?
Several bones preserve pathology, including a healed rib injury and damage on a hand claw. They show survival after trauma but do not identify the cause or prove habitual fighting.