How To Identify Your Finds (Part 6 of 10)
5) Identifying the Odontaspis winkleri teeth
[Odontaspis winkleri (pronounced "o-don-tass-pis wink-ler-eye") is yet another extinct Sand Tiger shark. It also belongs to the order Lamniformes, family Otodontidae. Lamniformes are commonly known as mackerel sharks] If you've followed the previous 4 steps for identifying your fossils, you'll likely have very few shark teeth left to ID. Of those that remain, one of the more likely suspects amongst them will be O. winkleri. Having said that, Odontaspis winkleri are not very common at Beltinge. In my experience, they make up less than 1% of finds. |
Other important details:
- Up to 20mm in size
- Anterior teeth are long, slender, sigmoidal and upright (See figure 1). In profile, they are very curved; laterals are similar to the anteriors except they lean towards the rear of the jaw.
- The crown is smooth-edged, flat on labial side, rounded on lingual side . Unlike most similar, smooth crowned teeth found at Beltinge, the cutting edge is incomplete. If the cusplets are missing, then this becomes the best way to tell them apart from, say, a tooth from a juvenile G. heinzelini.
- There are 1 or 2 long, robust, straight or weakly curved cusplets on either side of the crown. The inner one can be up to half the length of the main cusp. The outer one (where present) will be shorter. This goes for anteriors and laterals.
- The root is strongly bi-lobed and U shaped. Lobes are well separated and narrow (when viewed from the front) and deep when viewed in profile. Large lingual protuberance and nutrient groove at centre of root.
6) Identifying the Isurolamna affinis teeth
[Isurolamna affinis (pronounced "ice-euro-lam-na aff-in-iss") is yet another extinct Sand Tiger shark. It also belongs to the order Lamniformes]
If you've followed the previous 5 steps for identifying your fossils, the few that remain may include I. affinis. Note: The species is also known Isurolamna inflata.
It is quite rare at Beltinge. In my experience, they make up less than 1 in 500 finds.
Lateral teeth are fairly distinctive. As you can see from figure 2, the side cusps are V shaped and separate from the main cusp. The cutting edge runs all the way to the cusplets. The roots are very shallow, flat based, and square ended.
[Isurolamna affinis (pronounced "ice-euro-lam-na aff-in-iss") is yet another extinct Sand Tiger shark. It also belongs to the order Lamniformes]
If you've followed the previous 5 steps for identifying your fossils, the few that remain may include I. affinis. Note: The species is also known Isurolamna inflata.
It is quite rare at Beltinge. In my experience, they make up less than 1 in 500 finds.
Lateral teeth are fairly distinctive. As you can see from figure 2, the side cusps are V shaped and separate from the main cusp. The cutting edge runs all the way to the cusplets. The roots are very shallow, flat based, and square ended.
On the other hand, anterior teeth are a bit tricky. Looking at images of them on the web, it looks like you need to find complete teeth in order to reliably ID them. Even the experts struggle to tell the difference between various Mackerel shark anterior teeth, because they're remarkably similar.
I don't currently have any examples of the anteriors, so no photos to show you. But I can describe them and give you some links to follow.
Basically, the tooth should have a slender, upright main cusp, that has smooth, un-striated enamel, and a cutting edge extending to the base of the side cusps. It would likely have a single, small, pointed cusplet on either side of the main cusp.
All this is much like G.heinzelini. Where they differ seems to be that the root lobes look fatter than G.heinzelini (See here), hence their alternative name of Isurolamna inflata. It also seems that the edge of the enamel that meets the root in between the cusplets on the labial side forms a shallow 'W' (see right hand image at the top of this page), as opposed to a straight-ish line or a shallow, upside-down 'V'.
I don't currently have any examples of the anteriors, so no photos to show you. But I can describe them and give you some links to follow.
Basically, the tooth should have a slender, upright main cusp, that has smooth, un-striated enamel, and a cutting edge extending to the base of the side cusps. It would likely have a single, small, pointed cusplet on either side of the main cusp.
All this is much like G.heinzelini. Where they differ seems to be that the root lobes look fatter than G.heinzelini (See here), hence their alternative name of Isurolamna inflata. It also seems that the edge of the enamel that meets the root in between the cusplets on the labial side forms a shallow 'W' (see right hand image at the top of this page), as opposed to a straight-ish line or a shallow, upside-down 'V'.
Footnote
In the next part, I'll be moving onto some very different fossils, if you still have unidentified teeth with a single main cusp, you probably have something unusual and beyond this website. However, all is not lost: First, try matching your fossil against the links on this page.
If that doesn't help, or you're unsure, try taking your finds to an expert e.g. A rock & fossil shop, a local geology group, or a museum. You'd be surprised how approachable they can be.
How To Identify Your Finds (Part 7 of 10) - Notidanodon loozi