Dinosaur genus
Dryosaurus
Dryosaurus is a dinosaur genus known from bones, found in rocks 154.8–143.1 million years old, in the United States, France and Tanzania.
Confidence labels are switched off. Facts with low confidence, or where sources disagree, still carry a small dot: tap it for the reason.
At a glance
Data as of 10 October 2026- Named by
- Marsh 1894
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Described in
- O. C. Marsh (1894). The typical Ornithopoda of the American Jurassic. American Journal of Science, series 3 48: 85–90. Read it
medium
medium: Only PBDB gives this; its author and year match the naming authority (Marsh 1894).Sources
Given by: Paleobiology Database. The publication the Paleobiology Database gives as the authority for this genus name, usually the one that first named and described it.
- Lived
- Kimmeridgian to Tithonian, 154.8–143.1 million years ago
high
high: PBDB and NHM agree.Omnisaura calculation154.8–143.1 million years ago, from its dated fossil recordsmedium
medium: Omnisaura's calculation from 20 confirmed PBDB records.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Fossils found in
- United StatesFrance
medium
medium: Only PBDB records it (19 records).Tanzanialow
low: Only one PBDB record.disputed
low: NHM records it here but PBDB has no record in this country; awaiting an editor.mixed
mixed: Levels differ between entries; each has its own.Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: Union of all sources (ISO 3166).
- Rock formations
- Morrison FormationMarnes de Bléville
medium
medium: Only PBDB records it (19 records).Tendaguru Formationlow
low: Only one PBDB record.disputed
low: Only NHM gives this name and it matches no PBDB formation; awaiting an editor.mixed
mixed: Levels differ between entries; each has its own.Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: Canonical names, automatic and editor-approved matches applied.
- Family
- Dryosauridae
high
high: PBDB and NHM agree.Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: PBDB leads.
- Parent group
- Dryosauridae
medium
medium: Only PBDB gives this; nothing contradicts it.Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
- Species named in its records
- Dryosaurus altus, Dryosaurus elderae
Sources
Given by: Paleobiology Database (the species its fossil records are identified as).
- Diet
- herbivore (inferred for its group)
medium
medium: Only PBDB gives this, and it infers it for the whole of Ornithopoda, the group this genus belongs to, not from this genus's own fossils.Sources
Given by: Paleobiology Database. How it was chosen: PBDB, inferred from a group the genus belongs to.
- Way of life
- ground dwelling, gregarious (inferred for its group)
low
low: PBDB infers this way of life for the whole of Ornithischia; behaviour is rarely known for one genus.Sources
Given by: Paleobiology Database. How it was chosen: PBDB, inferred from a group the genus belongs to.
- Known from
- Bones
Sources
Given by: Paleobiology Database (what the name was based on).
Gaps are answers
What isn't known yet
- Type species: no source we use gives it yet.
- Order: no source we use gives it yet.
- Common names: no source we use gives it yet.
- What it was named after: no source we use gives it yet.
- Held back: 4 fossil records left out: identified only tentatively (for example "cf.", "?" or the name in quotation marks).
- Held back: 3 fossil records left out: identified as a related genus rather than this one.
- Resting on one source: 3 facts come from a single source with nothing against them (rated medium): authority (PBDB); parent group (PBDB); diet (PBDB).
Size and appearance aren't covered yet, and diet and way of life only as PBDB infers them for the wider group. Omnisaura leaves the rest out rather than guess.
Where sources disagree
2 openFormations
- records nothing herePBDB
- Tendaguru BedsNHM
One source names a formation the other does not. An editor hasn't ruled yet, so this is rated low until they do.
Countries
- FR, USPBDB
- TanzaniaNHM
One source records a country the other does not. An editor hasn't ruled yet, so this is rated low until they do.
Did it meet…?
No. Dryosaurus had gone at least 59.5 million years before Tyrannosaurus appears in the fossil record.
Going by the ages and rock formations of their dated fossils, as on the map. Compare their fossil sites on the map.
Connections
Genera linked to Dryosaurus by where and when their fossils were found, by classification and by who named them. Select a name to open its page.
Same rocks, same time 34
Genera found in the same rock units, from rocks of overlapping age, the most shared fossil sites first.
Named by Marsh 18
Genera whose naming authority includes the same surname. The authority has no initials, so different people who share a surname can appear together.
Found in United States 38
Other genera found in United States, from rocks of overlapping age, the most fossil sites there first.
Credits
Where this page comes from
- Paleobiology DatabaseCC BY 4.0 · fossil records, ages, classification
- Natural History Museum Data PortalCC0 1.0 · catalogued specimens
- WikidataCC0 1.0 · names and identifiers
- OmnisauraOmnisaura editorial · confidence levels and gaps
- PaleoMAP PaleoCoastlines (Kocsis and Scotese 2021)CC BY 4.0 · ancient coastlines on the small map
- Natural EarthPublic domain · today's coastlines
Pictures linked from this page are credited beside each one, with their own licences; the full list is in the JSON download.