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The collection/Halszkaraptor

EXHIBIT 141

Halszkaraptor

Halszkaraptor escuilliei

Halszkaraptor combines an unusually long neck with short forelimbs and a broad snout. [5]

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 / SKELETAL RECONSTRUCTION

A framework from the fossils

Halszkaraptor escuilliei skeletal reconstruction from MPC D-102/109, with long neck and missing bones in grey.

Halszkaraptor escuilliei skeletal reconstruction by M. Auditore, published with Cau and colleagues’ 2021 study of MPC D-102/109. Missing elements are grey; the scale bar is 10 cm. The drawing reconstructs preserved anatomy and missing pieces, while the surrounding outline and posture do not directly establish soft tissues or swimming behavior. [5]

Halszkaraptor escuilliei skeletal.png · M. Auditore. CC BY 4.0. Current Commons 1280 px preview converted to WebP and proportionally reduced for thumbnail use. No cropping, mirroring, anatomical edits or compositing; scale bar and source restoration retained. Source license applies to these versions.

Skeletal mounts and drawings may restore missing parts; the caption identifies the displayed material.

02 / MOVIE-STYLE INTERPRETATION

A cinematic imagination

Illustrative reconstruction of Halszkaraptor escuilliei; covering, colors and unpreserved anatomy are hypotheses.

Original cinematic interpretation of Halszkaraptor. Colors, soft tissues, scenery and missing anatomy are reconstructed artistic choices; this is not a directly observed individual or behavior. The animal is shown on land; aquatic habits, webbing and swimming behavior are not established by this illustration. 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 LENGTHSee the dossierEstimate scope matters
FOSSILS FOUNDMongolia[6]
CompareRead the dossierView the sources

MEET THE ANIMAL

Meet Halszkaraptor

Halszkaraptor was a Late Cretaceous dinosaur from Mongolia with an unusual combination of features. Its skeleton passed through the fossil trade, so its reported discovery location is less securely documented than a carefully excavated find. Powerful X-ray scans helped researchers check that its surprising bones genuinely belonged to one associated animal, rather than a misleading assembly of different fossils. [D6]

The animal had a broad snout, short forelimbs and an especially long neck. Its neck made up roughly half the distance from the snout to the hips, not half the entire animal including its tail. Details of its fingers and shoulder bones add to this distinctive body plan, while some missing regions still require reconstruction. [D5]

Researchers disagree about whether Halszkaraptor had an amphibious lifestyle, moving between land and water. Comparisons with other dinosaurs have challenged an aquatic interpretation of its features. The debate illustrates a difference between finding an unusual shape and proving what it did. A skeleton can suggest possible abilities without preserving a swimming event or showing exactly how often its owner entered water. [D2]

PREHISTORIC ANIMAL DOSSIER

A life in profile.

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

The skeleton is well preserved, while its proposed amphibious lifestyle remains contested. [D6] [D2] [D3]

Profile scope: Genus — Halszkaraptor; H. escuilliei, centered on MPC D-102/109. [D1]

Time
Late Cretaceous
Fossil locations in this exhibit
Mongolia
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

Not established

Not established here

The studied skull is 67.7 mm long. A checked whole-body adult reference is not supplied by the inspected cranial study. [D4]

Body mass

Inferred

About 1.5 kg (model assumption)

MPC D-102/109, subadult; 2025 metabolic analysis adopts the 2017 estimate. Mass is inferred, not a mature species average. [D7]

Diet and feeding

Debated

Small-prey interpretations debated

Earlier fish-feeding proposals were challenged; 2024 skull models instead favor invertebrate feeding. No directly identified meal establishes its diet. [D3] [D4]

Habitat and setting

Source supported

Reported Djadochta Formation provenance

Campanian Mongolia; a traded fossil was reported from Ukhaa Tolgod, so precise excavation context is less secure than an excavated specimen. [D1] [D6]

Movement

Debated

Bipedal; aquatic capability debated

Walking anatomy is compatible with two-legged movement. Amphibious interpretations and their terrestrial alternatives remain disputed. [D2] [D3]

Recognizable anatomy

Source supported

Long neck; broad snout; short forelimbs

Neck is half the snout-to-sacrum length, not half total length. The third finger exceeds the second; the wishbone contacts the sternum. [D5]

Reproduction & life together

Reproduction and nesting

Not established

Not established here

A subadult skeleton does not establish egg laying sites, nesting, breeding maturity or parental care. Aquatic hypotheses cannot locate its nests. [D1] [D7]

Mating and courtship

Not established

Not established here

The unusually long neck and shoulder anatomy do not identify a courtship display; reviewed studies establish no sex-specific ornament or mating sequence. [D5]

Social behavior

Not established

Not established here

Scans support a genuine single skeleton; its fossil-trade history provides no secure group association or social behavior. [D6]

Dossier research & sources

Sources and inspection notes for the claims in this profile.

  1. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs (Cau et al., 2017)Nature · Accessed 2026-10-02Original abstract and indexed diagnosis/type excerpts inspected; reported Ukhaa Tolgod/Djadochta provenance and subadult MPC D-102/109. Amphibious interpretation is contested. · Inspected: excerpt
  2. Halszkaraptor escuilliei and the evolution of the paravian bauplan (Brownstein, 2019)Scientific Reports · Accessed 2026-10-02Original full comparative argument inspected: proposed aquatic traits reinterpreted in broader maniraptoran evolution. · Inspected: page
  3. The body plan of Halszkaraptor escuilliei ... is not a transitional form along the evolution of dromaeosaurid hypercarnivory (Cau, 2020)PeerJ · Accessed 2026-10-02Original full abstract, comparative anatomy and rebuttal discussion inspected. Defends amphibious interpretation against Brownstein; no fossil swimming track or stomach contents. · Inspected: page
  4. Morphological disparity and structural performance of the dromaeosaurid skull informs ecology and evolutionary history (Tse, Miller and Pittman, 2024)BMC Ecology and Evolution · Accessed 2026-10-02Original cranial-model discussion and measurement table inspected: Hals skull 67.7 mm; shape supports invertebrate-feeding hypothesis, not piscivory, without resolving aquatic lifestyle. · Inspected: page
  5. Unusual pectoral apparatus in a predatory dinosaur resolves avian wishbone homology (Cau et al., 2021)Scientific Reports · Accessed 2026-10-02Full original pectoral description/updated diagnosis and figure captions inspected through EuropePMC XML. Furcula-sternum contact, neck 50% snout-sacrum length, third finger longer than second; missing elements grey in Auditore drawing. · Inspected: page
  6. Synchrotron sheds light on the amphibious lifestyle of a new raptorial dinosaur (2017)European Synchrotron Radiation Facility · Accessed 2026-10-02Institutional original research account inspected: fossil-trade provenance, scans showing genuine associated skeleton and Campanian Mongolia. Its aquatic certainty is tempered by subsequent papers. · Inspected: page
  7. Femoral metadiaphyseal and nutrient foramen perfusion suggests comparable maximal metabolic rates ... (Sena et al., 2025)PeerJ · Accessed 2026-10-02Original selected methods/results through EuropePMC XML inspected: MPC D-102/109 subadult, assumed 1.5 kg from Cau 2017 for metabolic modeling. This paper does not independently measure mass or settle aquatic ecology. · Inspected: page

THE STORY IN THE FOSSILS

A complete skeleton can leave ecology uncertain.

Tomography helped check that the unusual combination of bones belonged to one animal, even where anatomy remained hidden in rock. [6]

Later skull modeling challenged a fish-catching explanation for the broad snout. This does not, by itself, determine whether the animal entered water. [4]

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. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs (Cau et al., 2017)Nature · Accessed 2026-10-02Original abstract and indexed diagnosis/type excerpts inspected; reported Ukhaa Tolgod/Djadochta provenance and subadult MPC D-102/109. Amphibious interpretation is contested. · Inspected: excerpt
  2. Halszkaraptor escuilliei and the evolution of the paravian bauplan (Brownstein, 2019)Scientific Reports · Accessed 2026-10-02Original full comparative argument inspected: proposed aquatic traits reinterpreted in broader maniraptoran evolution. · Inspected: page
  3. The body plan of Halszkaraptor escuilliei ... is not a transitional form along the evolution of dromaeosaurid hypercarnivory (Cau, 2020)PeerJ · Accessed 2026-10-02Original full abstract, comparative anatomy and rebuttal discussion inspected. Defends amphibious interpretation against Brownstein; no fossil swimming track or stomach contents. · Inspected: page
  4. Morphological disparity and structural performance of the dromaeosaurid skull informs ecology and evolutionary history (Tse, Miller and Pittman, 2024)BMC Ecology and Evolution · Accessed 2026-10-02Original cranial-model discussion and measurement table inspected: Hals skull 67.7 mm; shape supports invertebrate-feeding hypothesis, not piscivory, without resolving aquatic lifestyle. · Inspected: page
  5. Unusual pectoral apparatus in a predatory dinosaur resolves avian wishbone homology (Cau et al., 2021)Scientific Reports · Accessed 2026-10-02Full original pectoral description/updated diagnosis and figure captions inspected through EuropePMC XML. Furcula-sternum contact, neck 50% snout-sacrum length, third finger longer than second; missing elements grey in Auditore drawing. · Inspected: page
  6. Synchrotron sheds light on the amphibious lifestyle of a new raptorial dinosaur (2017)European Synchrotron Radiation Facility · Accessed 2026-10-02Institutional original research account inspected: fossil-trade provenance, scans showing genuine associated skeleton and Campanian Mongolia. Its aquatic certainty is tempered by subsequent papers. · Inspected: page
  7. Femoral metadiaphyseal and nutrient foramen perfusion suggests comparable maximal metabolic rates ... (Sena et al., 2025)PeerJ · Accessed 2026-10-02Original selected methods/results through EuropePMC XML inspected: MPC D-102/109 subadult, assumed 1.5 kg from Cau 2017 for metabolic modeling. This paper does not independently measure mass or settle aquatic ecology. · Inspected: page

FOLLOW YOUR CURIOSITY

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