Anchiornis vs Pachycephalosaurus

A detailed side-by-side comparison of Anchiornis and Pachycephalosaurus, covering size, diet, classification, geologic period, and discovery history.

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Side-by-Side Comparison

Property Anchiornis Pachycephalosaurus
Scientific Name Anchiornis huxleyi Pachycephalosaurus wyomingensis
Classification Theropoda Pachycephalosauria
Period Jurassic Late Cretaceous Late
Diet Insectivore Herbivore
Length 0.4 m 4.5 m
Height 0.2 m 1.8 m
Weight 0 kg 450 kg
Discovery Year 2009 1943
Discovery Location Tiaojishan Formation, China Montana, USA
Named By Xu Xing et al. Barnum Brown & Erich Schlaikjer
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Size Comparison

Anchiornis 0.4 m

smaller than a human child

Pachycephalosaurus 4.5 m

roughly the length of a large SUV

Weight Comparison

Anchiornis 0 kg

lighter than a human adult

Pachycephalosaurus 450 kg

about 6 adult humans

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Timeline Comparison

Anchiornis
161.5 Mya Jurassic Late (Mesozoic) 145.0 Mya
Pachycephalosaurus
100.5 Mya Cretaceous Late (Mesozoic) 66.0 Mya
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Diet Comparison

Anchiornis

Insectivore

Anchiornis primarily fed on insects and other small invertebrates.

Pachycephalosaurus

Herbivore

Pachycephalosaurus was a plant-eater, feeding on vegetation like ferns, conifers, and cycads.

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Classification Comparison

Anchiornis

Clade: Saurischia

Group: Theropoda

(Beast feet)

Pachycephalosaurus

Clade: Ornithischia

Group: Pachycephalosauria

(Thick-headed lizards)

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Did You Know?

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Pachycephalosaurus was about 11.2x longer than Anchiornis.

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Pachycephalosaurus weighed roughly 4500x more than Anchiornis.

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Anchiornis was a insectivore while Pachycephalosaurus was a herbivore.

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Anchiornis lived during the Jurassic Late while Pachycephalosaurus lived during the Cretaceous Late, separated by roughly 44 million years.

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Pachycephalosaurus was discovered 66 years earlier, in 1943.

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Anchiornis belonged to Theropoda while Pachycephalosaurus belonged to Pachycephalosauria.

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