Early tetrapod — Acanthostega gunnari

Geologic period: Late Devonian — Famennian

Age: Late Devonian.

Feeding: Predatory feeding is inferred from skull and tooth anatomy.

Locomotion: Primarily aquatic locomotion; limbs were present before fully terrestrial walking evolved.

Body plan: Elongated aquatic tetrapod body with limbs bearing digits.

Evidence: Skeleton anatomy is fossil evidence. Movement and lifestyle are reconstructed from limb, rib, skull and tail anatomy.

Why it matters: Acanthostega is central to understanding how vertebrate limbs with digits evolved before tetrapods became fully terrestrial.

Plain Language Identity: A Late Devonian early tetrapod with limbs and digits but many adaptations for life in water.

What You Are Looking At: A cast of skeletal material rather than the original fossil.

Ecosystem: Late Devonian freshwater or nearshore aquatic environment.

Preservation: Visitor object is a cast based on fossil skeletal material.

Find Location: Greenland.

Open Questions: Do not portray Acanthostega as simply a modern land animal taking its first walk ashore.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://collections.si.edu/search/detail/edanmdm:nmnhpaleobiology_12307235

Enrichment Method: SAGE curated research pass; title and scientific name matched; evidence separated from inference

Scientific name: Acanthostega gunnari

Evidence / representation: Representative evidence-type visual; not the exact specimen.

Representative evidence-type visual; not the exact specimen.

Oceans Before Dinosaurs: The Rise of Complex Animal Life.