The sarcopterygian lungfish appeared in the Early Devonian, and their diversity increased by the Late Devonian, but the extant groups are only three genera and six species 3). Only two species, Scaumenacia curta and Fleurantia denticulata, are known from the Late Devonian Escuminac Formation of Miguasha 3), Canada, which is known for many Devonian fossils 1), 2), 3).
Scaumenacia is probably the best known lungfish of the extinct dipnoi 3).
The larger adult could reach 65 cm in length 3). Scaumenacia has typical sarcopterygian fleshy and long paired fins, pectral and pelvic fins. Furthermore, it has independent unpaired fins, two dorsal fins, a caudal fin and an anal fin, whereas the lungfishes after the Devonian have a long fused median fin, that is, a fusion of dorsal and caudal fins, or anal and caudal fins 1), 2).
The caudal fin is a reduced heterocercal 1). It appears too small for the overall balance of the body.
All exant lungfish are freshwater inhabitants, and Scaumenacia also seems to be fresh water, but the Escuminac Formation is a marginal marine environment 2), suggesting that Scaumenacia lived in brakish water or moved between fresh and marine water.
Although Scaumenacia was large in size, it was not a predator that prey on other fish, but seemed to feed on "clam shrimp" (nickname of Asmusia), a small crustacean with bi-valves 2), 3).
- Arratia G, Schultze HP, Casciotta J (2001) Vertebral column and associated elements in dipnoans and comparison with other fishes: Development and homology. [abstract] J. Morphol. 250(2): 101-172. (DOI: 10.1002/jmor.1062) (The full-text was reffered to ResearchGate.)
- Cloutier R (1996) Dipnoi (Akinetia: Sarcopterygii). In: Schultze HP, Cloutier R editors. Devonian ﬁshes and plants of Miguasha, Québec, Canada. München: Verlag Dr. Pfeil. p.198 –226. (The full-text was reffered to ResearchGate.)
- Dipnoi, Scaumenacia, Asmusia (From water to land - Miguasha National Park -).