Tag: fish

Eospinus

Eospinus daniltshenkoi, a tetraodontiform fish from the early Eocene of Turkmenistan (~56-48 mya). Only about 5cm long (2″), it was a close relative of modern boxfish and triggerfish, as well as a completely extinct group called spinacanthids.

It was heavily armored, with large plate-like scales creating a boxfish-like carapace, but its most distinctive feature was its multiple long spines – three dorsal spines on its back, a fourth on its head resembling a “horn”, a pair of smaller spines on the sides of its body, and one on its underside formed from partially fused vestigial pelvic fins.

Potanichthys

Potanichthys xingyiensis, a fish from the Middle Triassic of China, living around 235-242 million years ago.Measuring about 15cm long (6″), it was one of the oldest known fish capable of aerial gliding – possessing a “four-winged” body plan with enlarged pectoral and pelvic fins, and an asymmetrical tail with a long lower lobe. It was also almost completely scale-less, which may have helped to reduce drag and make it more aerodynamic.

Despite the similar appearance it had no close relation to modern flyingfishes, and was instead a result of convergent evolution in a completely different lineage of the ray-finned fishes.

Edestus

Edestus, a holocephalan fish from the Late Carboniferous (~315-299 mya) of Eurasia and North America. A relative of the “spiral-saw-mouthed” Helicoprion, it continuously grew a single row of teeth in each jaw, creating an arrangement often compared to a pair of pinking shears.

Multiple species of this genus have been named, with varying degrees of tooth bracket curvature, and the largest may have had body sizes similar to modern white sharks – about 6m long (19′8″).

Since Edestus is only known from fossilized tooth brackets, how exactly its jaws worked and what it ate with them is still a mystery. Many reconstructions end up either goofy or horrifying as a result, and so I’ve attempted to make this one look a bit more “normal”. And capable of closing its own mouth.

Edit: This reconstruction was based more on chimaeras than on other eugeneodontids, and is therefore probably very inaccurate. When I originally did this image I wasn’t aware body outlines were known for the group. For a much more accurate version see my 2020 version in the “Weird Heads” series.