Stethacanthus was a primitive proto-shark which swam the seas from the late Devonian Period to the end of the Carboniferous Period approximately 380-300 million years ago. Fossils of various species of this genus have been found worldwide.
Stethacanthus is distinctive for its highly modified front dorsal fin which resembles an anvil or a steam iron whose upper surface was covered in large tooth-like denticles. Another patch of enlarged denticles adorned the top of its head. Additionally, the pectoral and pelvic fins had long ribbon-like trailers. Scientists still don’t know why Stethacanthus had these features, but they were probably for sexual display.
Several species have been ascribed to the genus Stethacanthus, most of which measured 5 feet long. However, the species S. productus, which was the largest, measured 10 feet long! Fossils of Stethacanthus productus have been found in Iowa within the Burlington Formation, which dates to the first half of the Carboniferous Period 360-325 MYA.
Stethacanthus productus. © Jason R. Abdale (April 29, 2026).
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Categories: Paleontology, Uncategorized
DINOSAURS AND BARBARIANS 
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