Fish Spines

This is a dorsal fin spine with its basal supporting spine from a medium-size boney fish, a snook of the Family CENTROPOMIDAE. These two spines were found still articulated in Early Pleistocene mud. While snook are saltwater fish, they often are found - both as fossils and alive - in freshwater situations in Florida.

Here's what Robert L. Carroll says in his book, VERTEBRATE PALEONTOLOGY AND EVOLUTION:

The term spiny teleost (boney fish) refers to the fin spines that most members of this group possess. These are particularly conspicuous on the dorsal fin but also occur in the anal and paired [e.g. pectoral] fins. The stiff spines result from fusion of the two halves of primitively paired and jointed dermal fin rays into a median, unjointed structure. The spine loses its flexibility and is effectively moved as a unit by muscles attached to its base.

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