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Orthacanthus (Wikimedia Commons)


Orthacanthus (Greek for "vertical spike"); pronounced ORTH-ah-CAN-thuss


Shallow seas of Eurasia and North America

Historical Period:

Devonian-Triassic (400-260 million years ago)

Size and Weight:

About 10 feet long and 100 pounds


Marine animals

Distinguishing Characteristics:

Long, slender body; sharp spine jutting out from head


About Orthacanthus:

For a prehistoric shark that managed to persist for almost 150 million years--from the early Devonian to the middle Permian period--not a whole lot is known about Orthacanthus other than its unique anatomy. This early marine predator had a long, sleek, hydrodynamic body, with a dorsal (top) fin that ran almost the entire length of its back, as well as a strange, vertically oriented spine that jutted out from the back of its head. There's been some speculation that Orthacanthus feasted on large prehistoric amphibians (Eryops being cited as a likely example) as well as fish, but proof for this is somewhat lacking.

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