Fossil Record
The geological history of barnacles can be traced back to animals such as Priscansermarinus from the Middle Cambrian (on the order of 510 to 500 million years ago), although they do not become common as skeletal remains in the fossil record until the Neogene (last 20 million years). In part their poor skeletal preservation is due to their restriction to high-energy environments, which tend to be erosional – therefore it is more common for their shells to be ground up by wave action than for them to reach a depositional setting. Trace fossils of acrothoracican barnacle borings (Rogerella) are common in the fossil record from the Devonian to the Recent.
Barnacles can play an important role in estimating palæo-water depths. The degree of disarticluation of fossils suggests the distance they have been transported, and since many species have narrow ranges of water depths, it can be assumed that the animals lived in shallow water and broke up as they were washed down-slope. The completeness of fossils, and nature of damage, can thus be used to constrain the tectonic history of regions.
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