How To Identify Your Finds (Part 4 of 10)
3) Identifying the Gluekmanotodus heinzelini teeth
[Note: I was mistakenly calling this Carcharias hopei before] [Gluekmanotodus heinzelini is another extinct Sand Tiger shark. It belongs to the order Lamniformes, family Otodontidae. Lamniformes are commonly known as mackerel sharks. It is easily mistaken for C. hopei but that is from the Eocene and we're dealing with the Palaeocene at Beltinge] Gluekmanotodus heinzelini is the second commonest fossil at Beltinge. If you've taken out all the S. striata from your finds in step 1, G. heinzelini will make up most of the rest. However, it does look like a number of other species at Beltinge that have unstriated crowns. |
i) G. heinzelini is almost identical to Striatolamia striata except it doesn't have the striations we saw in step 1 (See picture on the right).
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iii) Now set aside, in a pile of their own, any teeth with 'wrinkles' (sometimes called 'stitching') at the junction between the root and the crown on the labial (flat) side (See picture to the right). Note: Sometimes these wrinkles are quite difficult to see, so have a magnifying glass/hand lens nearby. These might be Paleaohypotodus rutoti (See Part 5). |
iv) Next, put aside, on their own, any laterals where there is a noticeable gap between the main cusp and it's V-shaped cusplets as seen in the picture on the left. Also, any anteriors where the root lobes look 'swollen' or 'fatter' than other anteriors you've seen. These might be Isurolamna affinis (see Part 6).
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v) Lastly, set aside anything with cusplets that are proportionately larger than those of S. striata (See picture on the right). These might be Odontaspis winkleri (See Part 6). |
vi) There are two further un-striated species to think about before deciding it's a G. heinzelini: These are: 1) Anomotodon novus which is a small, slender looking tooth with no cusplets but the enamel extends out over the labial side of the root looking like flat cusplets.(( (See here for pictures).; 2) Jaekelotodus trigonalis which is a large (up to 35mm), robust, triangular tooth, has large rounded roots and small pointed cusplets (See here for pictures).
What remains after eliminating i) to vi) should all be G. heinzelini and look something like figures 1 and 2 below.
Other important details:
- Up to 35mm long
- Anterior teeth are long, slender, sigmoidal and upright (See figure 2); laterals tend to be shorter, relatively wider at the base, and lean toward the back of the jaw (see figure 1). However, upper laterals tend to be curved (see figure 1 above) whilst lower laterals often have no curvature to speak of.
- The crown is smooth-edged, flat on labial side, rounded on lingual side. Cutting edge extends to the base of the cusplets. Upper lateral crowns
- There's a single, small, strongly curved, pointed cusplet on either side of the crown. Laterals: the single cusplets are flattened and more pointy than on S. striata.
- The root is strongly bi-lobed. The angle between lobes for upper jaw teeth is around 100 - 120 degrees. Lowers have around 90 degrees. Anterior: well separated. Large lingual protuberance and nutrient groove at centre of root. Lateral: separated, broad & grooved.
More pictures of Gluekmanotodus heinzelini can be found here (Page 5).
How To Identify Your Finds (Part 5 of 10) - Palaeohypotodus rutoti
How To Identify Your Finds (Part 5 of 10) - Palaeohypotodus rutoti