Introduction

Helicoprion is probably one of, if not the weirdest, fish in the Permian period. Yes, it's not actually a shark, it's only shark-like, even though sharks have existed since the ordivician period. The most notable feature of this fish is it's tooth whorl (yes that's actually how it's spelled don't come at me), which was likely positioned on the lower jaw and probably used to catch prey with.

I like the fish, it's awesome, it's cool. It's mildly horrific because of it's jaw. I like it, that's why I made this page.

Habitat

The fossils of Helicoprion have been found across the world, including: America, Austualia, Europe, and Asia, indicating a world-wide distributon.

Appearence

There are actually 3 currently known species of helicoprion, but the only differnce in anatomy is the shape of the tooth whorl (webmaster's note: most of the fossils of helicoprion is only the tooth whorl. By comparing post-cranial remains with other species from it's order, that's how we figured out it's relative appearence, so this section may be inaccurate in the future if further information on the difference between species comes out), specifically, the tooth crowns, which only becomes apparent after around the 85th tooth.

H. davisii, one of the 3 known species, is the easiest to differenciate, with it's tall, widely-spaced tooth crowns and forward-curved tooth tips. H. bessonowi has short, closly spaced crowns and backwards-curved teeth, with a narrow shaft and wide tooth base. H. ergassaminon is between these two others, with tall but closly spaced crowns and tooth bases angled similarly to H. davisii.

Due to the rarity, there is scarce info on Helicoprion's anatomy beyond the tooth whorls, with the best perserved specimin being that of a H. davisii, one which was found in 1950 near a mine in Idaho, but it was originally identified as a H. ferrieri (which is just a synonym for H. davisii). In 2013, a CT scan of the fossil revealed it had a nearlt complete upper and lower jaw, still articulate and perserved in 3 dimensions.

Helicoprion had an autodiastylic jaw suspension, which basically means that the skull is attached to the upper jaw, and the lower jaw is directly attached to the upper jaw. It was a very primitive way of jaw attachment, but can be found in the Helicoprion's desendents--Chimeras.

One species had odontodes, or tooth-like scales near internal openings. Often, H. bessonowi has been assosiated with these scales in fossils. Not much info putting here about this otherwise, so I'll move on.

Sources/futher reading

Wikipedia article on Helicoprion
Australian Museum
Jaw Suspension
Odontode info