Body length
Not establishedNot established here
No defensible total-length interval adopted. The 2023 humerus comparison permits Deinonychus-like size or a smaller animal with relatively longer arms; neither establishes an adult range. [D2]
EXHIBIT 259
Dineobellator
Dineobellator notohesperus
Dinosaur
A New Mexico dromaeosaur whose arm bones preserve feather-attachment evidence. [3]
TWO WAYS TO PICTURE THE PAST
Science & the silver screen
Compare the evidence with the familiar movie image. The illustrations are not to a shared scale.
01 / SOURCE-INFORMED RECONSTRUCTION
A life reconstruction from the evidence
Image unavailableIllustrative life reconstruction of Dineobellator in a period-appropriate environment; coloration and missing anatomy are interpretations.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. [1]
Source-informed reconstruction. Appearance evidence [1]. Original illustration; missing anatomy, coloration and scenery include interpretation.
Fossils constrain this life reconstruction. Missing anatomy, coloration and the environmental scene include interpretation; the dossier explains the evidence limits.
02 / MOVIE-STYLE INTERPRETATION
A cinematic imagination
Image unavailableIllustrative reconstruction of Dineobellator notohesperus; missing anatomy, pose, skin and colors are hypotheses.The exhibit and its credited image source remain available.
An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. Lighting, coloration and scenery are artistic choices. This image does not document a fossil locality or behavior.
Original artwork · artistic interpretation.
Scientific view: source-informed reconstruction, credited paleoart or specimen-based imagery. Movie-style view: Original artistic interpretation. Reconstructions involve uncertainty.
PERIODLate Cretaceous[2]
DIETCarnivoreEvidence and uncertainty in the dossier
TOTAL LENGTHSee the dossierEstimate scope matters
FOSSILS FOUNDUnited States[1]
MEET THE ANIMAL
Meet Dineobellator
Dineobellator was a feathered dinosaur from what is now New Mexico. Researchers found small bumps on its forearm bone where large feathers attached. This is a useful clue even though the feathers themselves are missing. Its fossil therefore supports a feathered reconstruction, while leaving the colors and many details of the plumage uncertain. [D3]
The animal belongs to the dromaeosaur group, which includes several familiar clawed predators. Its teeth, arm bones, claws and tail bones helped scientists identify a distinct species. The original discovery contains only part of one skeleton, so a complete drawing requires comparisons with relatives. It does not prove a particular hunting scene, a favorite prey animal or coordinated pack hunting. [D1]
A later examination revised some bone identifications and reconsidered its size. Its upper arm resembles that of Deinonychus in length, but this could indicate a similarly sized, lighter animal or a smaller one with longer arms. The later family-tree analysis also left its closest subgroup uncertain. Revisiting a fossil can therefore improve the account without making every answer definite. [D2]
PREHISTORIC ANIMAL DOSSIER
A life in profile.
The animal, the evidence, and the questions still open.
The 2023 reassessment revised several bone identifications and its family-tree position; the original smaller size comparison remains uncertain. [D2]
Profile scope: The exhibit concerns Dineobellator notohesperus, based on the partial individual SMP VP-2430. [D1]
- Time
- Late Cretaceous
- Fossil locations in this exhibit
- United States
How to read the evidence
Source supported identifies a description documented by the cited source. Inferred marks a reconstruction or functional estimate. Debated marks competing interpretations. Not established means the sources reviewed for this dossier do not support a firm conclusion; it does not mean a behavior never occurred.
A size reference is an estimate, not a population range. Nesting evidence does not by itself establish courtship, mate choice, or lifelong pairing.
Body mass
Not establishedNot established here
No precise mass adopted. Published ecological size classes and comparisons are approximate; missing anatomy prevents a narrow specimen-specific interval. [D2]
Diet and feeding
InferredCarnivory inferred.
Dromaeosaurid teeth and grasping anatomy support animal feeding; a particular prey species or hunting method is not demonstrated. [D1]
Habitat and setting
InferredTerrestrial Naashoibito Member, New Mexico.
Sandstone preserved the partial skeleton; competing age estimates caution against assigning a precise death date. [D2]
Movement
InferredTwo-legged terrestrial movement.
Tail and limb anatomy suggest maneuverability, without direct evidence of speed or coordinated hunting. [D3]
Recognizable anatomy
InferredFeather attachments and distinctive arm, claw and tail bones.
Ulnar quill knobs support forearm feathers; missing plumage, most skull and complete foot anatomy are reconstructed comparatively. [D1]
Reproduction & life together
Reproduction and nesting
Not establishedNot established here
No nest or eggs assigned in reviewed material. The report's nest illustration is a restoration; the excavated partial individual does not establish nesting or parenting. [D3]
Mating and courtship
Not establishedNot established here
No supported mating display. Bone injuries and feather attachments do not identify sex-specific appearance or a courtship ritual. [D3]
Social behavior
Not establishedNot established here
Everyday social organization remains unresolved. A damaged claw was interpreted as possible combat evidence, but does not prove pack living, cooperative hunting or a specific opponent. [D1]
Dossier research & sources
Sources and inspection notes for the claims in this profile.
- Jasinski, Sullivan and Dodson (2020), New dromaeosaurid dinosaur from the Late Cretaceous of New MexicoScientific Reports · Accessed 2026-10-08Full original description inspected for quill knobs, partial skeleton, locality and inferred function. · Inspected: page
- Jasinski et al. (2023), Osteology and reassessment of Dineobellator notohesperusThe Anatomical Record · Accessed 2026-10-08Accessible full publisher page inspected for 27 identified elements, revised bones, size alternatives, pathologies and unresolved eudromaeosaur placement. · Inspected: page
- New feathered dinosaur was one of the last surviving raptors (2020)University of Pennsylvania · Accessed 2026-10-08Institutional report inspected for feather-attachment interpretation and recovery story; its early size estimate and nest illustration are not adopted as fossil measurements or reproduction evidence. · Inspected: page
THE STORY IN THE FOSSILS
Evidence behind Dineobellator
Tiny attachment bumps on the forearm connect an incomplete fossil to an important living feature: large feathers anchored to the bone. Their presence does not preserve the feather color or the entire wing outline. [3]
Re-examining a previously described skeleton can change interpretations without requiring a new name. The later study reassigned uncertain fragments and considered alternatives to the original size comparison. [2]
A note on scale and time
The dossier identifies the scope of each reference estimate. A mount, an individual fossil and a species-wide adult range are different measurements. Comparison metrics remain unavailable where adult scope has not been established. Unknown does not mean zero.
Sources & editorial notes
Sources support the stated claims and scopes. Refer to the evidence notes for uncertainty.
- Jasinski, Sullivan and Dodson (2020), New dromaeosaurid dinosaur from the Late Cretaceous of New MexicoScientific Reports · Accessed 2026-10-08Full original description inspected for quill knobs, partial skeleton, locality and inferred function. · Inspected: page
- Jasinski et al. (2023), Osteology and reassessment of Dineobellator notohesperusThe Anatomical Record · Accessed 2026-10-08Accessible full publisher page inspected for 27 identified elements, revised bones, size alternatives, pathologies and unresolved eudromaeosaur placement. · Inspected: page
- New feathered dinosaur was one of the last surviving raptors (2020)University of Pennsylvania · Accessed 2026-10-08Institutional report inspected for feather-attachment interpretation and recovery story; its early size estimate and nest illustration are not adopted as fossil measurements or reproduction evidence. · Inspected: page
KEEP EXPLORING
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