Leedsichthys: Research Database Pachycormidae (Stem-group Teleosti) · Late Jurassic (~155-150 MYA) · Europe — England, Germany, France, Chile
Research Note: Leedsichthys is the largest known fish (and largest known vertebrate) to have ever lived. Despite its enormous size, it was a filter feeder — straining plankton from seawater using gill rakers, similar to modern basking sharks. Its fossils are notoriously difficult to identify because bones often went unrecognised.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
| Named and described as a giant filter-feeding teleost — described as Leedsichthys problematicus from the Jurassic of England; recognized as a giant filter-feeding fish; established its status as the largest known fish and the largest vertebrate ever Foundational paper establishing the genus and its significance |
Confirmed | A | 1988 | Fossil | Martill, Neues Jahrbuch fur Geologie und Palaontologie 12 citations |
Foundational |
| Tail anatomy and locomotion — detailed study of Leedsichthys tail (fin) structure; reveals adaptations for slow cruising while filter feeding; anatomical features consistent with a large passive suspension feeder Clarifies how such a massive filter feeder moved and fed |
Confirmed | A | 2004 | Comparative | Martill et al., Acta Palaeontologica Polonica 11 citations |
Locomotion |
Status: Confirmed Direct evidence Debated Counter-studies Grade: A Strong consensus B Single study
What We Still Don’t Know About Leedsichthys
- Maximum size: Estimates range from 10m to 30m depending on methodology — no complete specimen known.
- Color: Completely unknown.
- Gill rakers: How filter apparatus worked is inferred from relatives.
- Why it went extinct: Decline of the Pachycormidae in the Cretaceous is unexplained.
- Growth rates: Unknown.
- Geographic range: Fossils found across Europe and Chile but full range unclear.
- Reproduction: Completely unknown.
Fossil Discovery Map of Leedsichthys
Explore the known fossil locations of Leedsichthys, one of the largest bony fish to ever exist.
In Detail About Leedsichthys
The secret to the large size of Leedsichthys is probably down to its lifestyle as a filter feeder.
This method of feeding requires very littler effort other than opening the mouth and cruising near the surface of the water.
Such a method of feeding requires only a slow metabolism as it is not actively hunting for prey.
Its large size however may mean that it was possibly gigantothermic like many of the large fish we know today.
Because of the fragmentary nature of recovered remains, the exact size has been open to much speculation.
Most researchers agree that a size of nine to ten meters long is realistic, but also recognise isolated remains that are larger than they appear in more complete specimens.
This in turn has pushed the maximum estimate to a potential sixteen meters long.
In contrast, the largest living fish today is the whale shark with a maximum recorded body length being just over twelve and a half meters.
Some estimates have further pushed the maximum size of Leedsichthys to beyond twenty metres.
Leedsichthys has been named after Alfred Nicholson Leeds who first discovered it in 1886. The type species L. problematicus was so named because of the difficulty involved in recovering and reconstructing the first specimen.
Further reading
- – Preliminary notes on some new and little-known British Jurassic fishes, Arthur Smith Woodward – 1889.
- – The tail of the Jurassic fish Leedsichthys problematicus (Osteichthyes: Actinopterygii) collected by Alfred Nicholson Leeds – an example of the importance of historical records in palaeontology, J. J. Liston & L. F. Noe – 2004.
- – Homologies amongst the fragments: searching for synapomorphies in shattered skulls. In: Poyato-Ariza FJ (ed) Fourth International Meeting on Mesozoic Fishes – Systematics, Homology and Nomenclature, Extended Abstracts, J. J. Liston – 2005.
- – Lured by the Rings: Growth structures in Leedsichthys. In: Poyato-Ariza FJ (ed) Fourth International Meeting on Mesozoic Fishes – Systematics, Homology and Nomenclature, Extended Abstracts., J. J. Liston, L. Steel & T. J. Challands – 2005.
- – The occurrence of the Middle Jurassic pachycormid fish Leedsichthys. – Oryctos 9: 1-36. – J. J. Liston – 2010.
