Organism · Lobe-fins and tetrapods
Eusthenopteron foordi
Source time context (not species duration) · ≈ 420–359 Ma
Inferred life reconstruction
Eusthenopteron foordi
Overview
Eusthenopteron foordi is a Late Devonian fish with fleshy fins. Inside its pectoral fins are structures compared with limb bones. Fossils from present-day Canada bring fish and tetrapod bodies into view together.[1][2]
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Key facts
The internal bones of our arms and a fish’s fins can be compared. Eusthenopteron’s pectoral fins contain bones corresponding to the upper arm and forearm. Beyond them, fin rays continue outward in an intriguing combination.[1]
Time and place
It is a Late Devonian fish from around 380 million years ago. Important fossils came from Miguasha in present-day Quebec, Canada. Fish fossils from this region are compared together in research on the history of early limbs.[2]
The time range describes source context, not the complete duration of this species.
Size, form and skeleton
It has one pair of fleshy pectoral fins and one pair of pelvic fins. A first and second dorsal fin lie on the back, and an anal fin is also distinguished. Bones inside the fins can be examined alongside the fin rays outside.[3][1]
Eusthenopteron specimen 7454 in Quebec’s cultural heritage inventory is 23.5cm long. This is the size of one individual with a complete side profile preserved, not the maximum length the species could attain.[20]
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Habitat and reproduction
It is a lobe-finned fish that lived in water. The skeletons of fins along the sides of the body and the arrangement of several fins are studied together. Comparing growth specimens also allows exploration of how the fish’s body changed as it grew.[1][3]
Fossil discovery
To reveal internal bones, researchers gradually ground down fossils and recorded sections. Later specimens were also studied by CT. Changing methods of looking inside rock added new information about the same fish’s body.[1]
References
- University of Texas DigiMorph — Eusthenopteron foordi
- Natural History Museum — Eusthenopteron from Miguasha
- Leblanc2005 — Study of growth in Eusthenopteron
- Shubin et al.2006 — The pectoral fin of Tiktaalik
- Cloutier et al. (2020) — Elpistostege and the origin of the vertebrate hand
- Sépaq Miguasha (2013) — The discovery story of Elpistostege
- Cloutier et al. 2020 · UQAR-hosted Nature paper, indexed body excerpt
- International Commission on Stratigraphy (2024) — Geological time chart
- Charest et al. (2023) — Median fins of fishes and evolution
- University of Texas DigiMorph — Eusthenopteron foordi
- Natural History Museum — Eusthenopteron from Miguasha
- Leblanc2005 — Study of growth in Eusthenopteron
- Great Canadian Lagerstätten4. The Devonian Miguasha Biota (Québec)
- Béchard et al. (2014) — Bothriolepis examined using 3-dimensional digital imaging
- International Commission on Stratigraphy (2024) — Geological time chart
- University of Texas DigiMorph — Eusthenopteron foordi
- Natural History Museum — Eusthenopteron from Miguasha
- Leblanc2005 — Study of growth in Eusthenopteron
- Great Canadian Lagerstätten4. The Devonian Miguasha Biota (Québec)
- Québec cultural heritage register — Eusthenopteron specimen 7454
Research questions
How do bones within fins correspond to bones of arms and legs? Eusthenopteron is compared with other fishes such as Tiktaalik. Placing head, body, and fin structures side by side reveals the varied bodies of early tetrapod relatives.[1]
Observation
Follow the fin rays outward from the fleshy part of a pectoral fin. Then examine the other dorsal and ventral fins to reveal the arrangement of the whole fish body.[1][3]
Related organisms
Tiktaalik roseaeLobe-fins and tetrapodsSource time context (not species duration) · ≈ 420–359 MaDifferent arrangements of bones inside fins
The fins of Eusthenopteron and Tiktaalik provide evidence for comparing the bodies of early tetrapod relatives. Viewing internal bones alongside external fin rays allows exploration of the structures of different fishes.
Elpistostege watsoniLobe-fins and tetrapodsSource time context (not species duration) · ≈ 420–359 MaExploring bones inside fins at Miguasha
Elpistostege watsoni and Eusthenopteron foordi connect the Late Devonian record of Miguasha in present-day Quebec, Canada. Internal bones of the pectoral fins of both species became evidence for studying the history of early limbs. Follow the visible fins together with the bones preserved inside them. In 1892, Eusthenopteron’s fins were noted to resemble tetrapod limbs.
Bothriolepis canadensisJawed vertebratesSource time context (not species duration) · ≈ 420–359 MaArmor and fleshy fins at Miguasha
The Late Devonian strata of Miguasha preserve Bothriolepis canadensis with hard armor and Eusthenopteron foordi with fleshy paired fins. At the same fossil locality in present-day Quebec, Canada, compare how different body coverings and fin arrangements can be. A fossil found here in the nineteenth century was initially regarded as a small turtle, but a 2013 review explains that it was probably Bothriolepis.