Tetrapods Lobe-finned fishes Other fish groups
Invertebrates plants Traces
Ray-finned fishes – Palaeoniscoids were early ray-finned fishes, ancestral to most of today’s bony fish (such as herring, salmon, and anything in your fridge or fishtank!).
Palaeoniscoids were coated in a bony coat of shiny scales.
Palaeoniscoid scales are extremely numerous, but patches of the whole skin like this are scarce.
Their shiny scales and other bony parts are found in great numbers in some Blue Beach rocks. Species of Elonichthys, Rhadinichthys, and Canobius are fairly common. A large form plus a new deep-bodied form are also present. As far as predators go, the palaeoniscoids weren’t all that large, yet they were quite successful. This was partly because they were fairly clever, quick and agile. They also likely traveled in large schools for safety-sake.
Acanthodians – The common name “spiny sharks” gives a false impression that these fish are related to the elasmobranches (true sharks). Instead, the acanthodians are a very primitive group of jawed fish whose relationships with other groups remains in question. They have very few bony parts – most notably they have spines that project in front of the fins, and these bony spines are the most common parts found. These fish had a lower jaw bone (mandible) but were toothless, so they are believed to have been filter-feeders – vacuuming up small organisms as they swam about. Also, having so few bony parts meant they were lightweight fishes that probably did not swim along the bottom. The spines were strictly defensive, there to discourage larger predators from swallowing the otherwise defenceless acanthodians.
Ornate fin-spines of Gyracanthides are usually found as fragments. This complete spine is a rare find.
Elasmobranches – Most sharks over time have lived in the salty waters of the oceans, but some Carboniferous types were adapted to freshwater. These fish also developed bony spines. Like acanthodians, they built their skeletons mainly out of cartilage. Ctenacanthus from Blue Beach is known almost strictly from its spines. A single mandible with rounded teeth suggest they might have fed on shelly-creatures, as this kind of specialized dentition is usually used to crush and break through shells.