Produced by the Population Genetics and Evolution class, Furman University

The Devonian: Eusthenopteron
Eusthenopteron is a genus of extinct, lobe-finned fish that lived during the Late Devonian period (Encyclopedia Britannica 2010). Nicknamed the “Fish with Legs”, Eusthenopteron are scientifically important because they are one of the evolutionary connections between fish and land vertebrates (White and Kazlev 2010). Living mainly in shallow areas and reaching lengths up to 6 feet, Eusthenopteron were active carnivores that had small teeth and stubby fins (Encyclopedia Brittanica 2010). These fins were studied extensively and found to contain well developed internal skeletons that include the humerus, ulna and radius in the fore-fin, and a femur, tibia, and fibula in the pelvic fin (Murphy 2006). The largest fossil records found of Eusthenopteron is in Quebec, Canada. This is where Erik Jarvik, of the Swedish Museum of Natural History, spent 40 years collecting fossils and studying the skull bones of a perfectly preserved specimen. Jarvik found that the pattern of the skull bones in Eusthenopteron were very similar to that of the early tetrapods, concluding that the Eusthenopteron are more closely related to land vertebrates than to modern fish (Ahlberg 2007). For an interesting video by Animal Planet on Eusthenopteron, click here.

Page by Julia Bobo
Top: Skeletal shapes of ancestors of tetrapods, with Eusthenopteron at the very right; from Devonian Times
Bottom: Reconstruction of Eusthenopteron, from: The University of Edinburgh

Ahlberg P. 2007. Eusthenopteron foord Digital Morphology. Accessed February 24, 2010.

Murphy DC. 2006. Tetrapods Answer.Devonian Times. Accessed February 24, 2010

Encyclopædia Britannica. 2010. Eusthenopteron.. Accessed 24 Feb. 2010.

White T and Kazlev MA. 2010. Sarcopterygii: Osteolepiformes: Eusthenopteron. palaeos.com. Accessed February 24, 2010.