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The collection/Masiakasaurus

EXHIBIT 234

Masiakasaurus

Masiakasaurus knopfleri

Dinosaur

Masiakasaurus was a small predatory dinosaur with an unusual row of forward-pointing front teeth. [2]

Evidence profile

TWO WAYS TO PICTURE THE PAST

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

Illustrative life reconstruction of Masiakasaurus in a period-appropriate environment; coloration and missing anatomy are interpretations.

An illustrative reconstruction. Compare its anatomy with the evidence and limitations in the dossier. [2]

Source-informed reconstruction. Appearance evidence [2]. 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

Illustrative reconstruction of Masiakasaurus knopfleri; missing anatomy, pose, skin and colors are hypotheses.

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[1]
DIETCarnivoreEvidence and uncertainty in the dossier
TOTAL LENGTH2–2 mEstimate scope matters
FOSSILS FOUNDMadagascar[1]
CompareRead the dossierView the sources

MEET THE ANIMAL

Meet Masiakasaurus

Masiakasaurus lived in Madagascar near the end of the Cretaceous. Its front teeth pointed forward rather than standing in an ordinary upright row. Other teeth farther back had different shapes. This unusual dental arrangement makes it easy to recognize, but teeth alone cannot tell us every animal it ate or exactly how it caught a meal. [D2]

More discoveries helped scientists assemble a clearer picture of its skeleton. It had a long, low head, a balancing tail and forelimbs that were useful rather than extremely tiny. Some parts remain missing, including the lower arm bones discussed in the detailed study. Drawings must therefore combine real fossil observations with carefully identified comparisons to related dinosaurs. [D1]

Studies of thin bone sections show that small size was not simply the result of youth. The largest sampled shin bone had an outer layer associated with the end of skeletal growth. Researchers also found that growth was relatively slow. Its sturdy and slender bone forms do not establish male and female appearances, so the collection colors are imaginative choices. [D3]

PREHISTORIC ANIMAL DOSSIER

A life in profile.

The animal, the evidence, and the questions still open.

Additional fossils revealed a long, low skull and useful forelimbs. Several missing bones still require comparative restoration. [D1]

Profile scope: Genus — Masiakasaurus knopfleri; type dentary UA 8680 and referred Maevarano material. [D1]

Time
Late Cretaceous
Fossil locations in this exhibit
Madagascar
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 length

Inferred

About 2 m (museum reference)

Educational genus estimate; no particular fossil individual or growth stage is specified. [D4]

Body mass

Not established

Not established here

No maturity-qualified numerical mass is adopted from the reviewed directory. [D4]

Diet and feeding

Inferred

Animal feeding inferred

Predatory teeth support carnivory; particular prey and hunting tactics remain unverified. [D2]

Habitat and setting

Inferred

Seasonal terrestrial setting

The histology study discusses semiarid seasonal conditions as environmental context, not a measured preference. [D3]

Movement

Inferred

Bipedal reconstruction

Hindlimb and vertebral anatomy support two-legged movement; useful arms differ from the tiny arms of some relatives. [D1]

Recognizable anatomy

Source supported

Procumbent front teeth

The front lower teeth angle strongly forward; tooth shapes change along the jaw. [D2]

Reproduction & life together

Reproduction and nesting

Not established

Not established here

Reviewed fossils do not identify a genus-specific nest or egg. [D2]

Mating and courtship

Not established

Not established here

Reviewed skeletal material does not establish mating displays. [D1]

Social behavior

Not established

Not established here

Several recovered individuals do not demonstrate packs or stable social groups. [D1]

Dossier research & sources

Sources and inspection notes for the claims in this profile.

  1. New Materials of Masiakasaurus knopfleri ... and Implications for the Morphology of the Noasauridae (Carrano, Loewen and Sertich, 2011)Smithsonian Contributions to Paleobiology 95 · Accessed 2026-10-06Original monograph abstract, systematic section, skull/dentition, forelimb and manual reconstruction, and discussion inspected. Type UA 8680; Maastrichtian Maevarano Formation. Radius and ulna remain unknown; four-finger restoration is comparative, not demonstrated. Bone assemblages are not a behavioral observation. · Inspected: page
  2. A bizarre predatory dinosaur from the Late Cretaceous of Madagascar (Sampson, Carrano and Forster, 2001)Nature 409:504–506; doi:10.1038/35054046 · Accessed 2026-10-06Original abstract and accessible figure captions inspected; small predatory Maastrichtian theropod, procumbent and heterodont dentition. Initial 1.8 m reconstruction is not merged into a species range with the later museum reference. · Inspected: abstract
  3. Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri (Lee and O'Connor, 2013)Journal of Vertebrate Paleontology 33(4):865–876 · Accessed 2026-10-06Original abstract inspected: four femora/three tibiae, largest tibia external fundamental system, slow growth, small adult size; robust/gracile morphotypes associated with maturity, not proven sexes. Seasonal semiarid environmental comparison is an inference. · Inspected: abstract
  4. Masiakasaurus dinosaur directoryNatural History Museum, London · Accessed 2026-10-06Directory inspected for 2.0 m educational reference, Madagascar, carnivory and species spelling. Its older numerical age interval is superseded by original Maastrichtian evidence. · Inspected: page

THE STORY IN THE FOSSILS

Evidence behind Masiakasaurus

Forward-directed front teeth give this predator a distinctive profile, but they do not identify one specific food. [2]

Bone histology independently supports a genuinely small adult animal; the fossils are not merely babies of a giant theropod. [3]

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.

  1. New Materials of Masiakasaurus knopfleri ... and Implications for the Morphology of the Noasauridae (Carrano, Loewen and Sertich, 2011)Smithsonian Contributions to Paleobiology 95 · Accessed 2026-10-06Original monograph abstract, systematic section, skull/dentition, forelimb and manual reconstruction, and discussion inspected. Type UA 8680; Maastrichtian Maevarano Formation. Radius and ulna remain unknown; four-finger restoration is comparative, not demonstrated. Bone assemblages are not a behavioral observation. · Inspected: page
  2. A bizarre predatory dinosaur from the Late Cretaceous of Madagascar (Sampson, Carrano and Forster, 2001)Nature 409:504–506; doi:10.1038/35054046 · Accessed 2026-10-06Original abstract and accessible figure captions inspected; small predatory Maastrichtian theropod, procumbent and heterodont dentition. Initial 1.8 m reconstruction is not merged into a species range with the later museum reference. · Inspected: abstract
  3. Bone histology confirms determinate growth and small body size in the noasaurid theropod Masiakasaurus knopfleri (Lee and O'Connor, 2013)Journal of Vertebrate Paleontology 33(4):865–876 · Accessed 2026-10-06Original abstract inspected: four femora/three tibiae, largest tibia external fundamental system, slow growth, small adult size; robust/gracile morphotypes associated with maturity, not proven sexes. Seasonal semiarid environmental comparison is an inference. · Inspected: abstract
  4. Masiakasaurus dinosaur directoryNatural History Museum, London · Accessed 2026-10-06Directory inspected for 2.0 m educational reference, Madagascar, carnivory and species spelling. Its older numerical age interval is superseded by original Maastrichtian evidence. · Inspected: page

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