Anomotodon sheppeyensis
Anomotodon sheppeyensis
View age-specific evidence and explanation
| Age | Recorded Occurrences | Localities | Rarity |
|---|---|---|---|
| Ypresian | 6 | 6 | Not yet established |
These counts describe published LBPS Occurrence records with directly assigned, unambiguous geological-unit mappings—not specimen abundance. Records at restricted Localities and ambiguous or unsupported ages are excluded. Species-level age labels are not used as proof of an age-specific Occurrence.
Specimen-based rarity requires comparable, correctly identified physical fossils, geological provenance and publication permissions. It does not estimate your chance of finding a fossil or collecting access.
Quick Identification
What to look for: On front teeth, look for a long, narrow pointed crown that may bend into a noticeable S-shape. Teeth from farther along the jaw can be shorter and more inclined, and the base normally lacks large projecting side cusplets.
Useful check: Turn a well-preserved tooth over and look closely at the base of its inner (lingual) face. Some front and near-front teeth show faint, short vertical folds there. Check the whole crown and root, because these folds can be very weak or missing in other tooth positions.
How to tell it apart: Anomotodon novus is usually described as lacking the comparable lingual crown ornament seen on some A. sheppeyensis anterior teeth. Other slender shark teeth, such as Striatolamia, can also look similar; compare crown shape, folds and the root together, not any single character.
Be careful: A straight-looking tooth does not automatically rule out A. sheppeyensis, and missing folds on a lateral tooth are not decisive. Broken tips and absent roots often prevent species-level identification.
Summary
Some of the front teeth of Anomotodon sheppeyensis seem almost to draw an S through the air. Their long, fine crowns can curve in one direction and then another, quite unlike the straight pointed teeth many people imagine when they think of a shark. The curve is especially evident in certain teeth interpreted as lower anterior positions; other teeth attributed to the same animal have different proportions and outlines.
This shark's scientific story began with fossils from the early Eocene London Clay of the Isle of Sheppey. Its name-bearing tooth, now held in the Natural History Museum as NHMUK P.30804, gives the species a tangible link to the island. Alongside related specimens, it helps reveal a mouth that was probably far less uniform than an isolated tooth would suggest. Exactly what such curved teeth meant for feeding remains uncertain without a complete jaw.
The appeal of A. sheppeyensis lies in that surviving fragment of individuality. The graceful, unexpected curve is not a reconstructed feature drawn onto an imagined shark. It is a real piece of the anatomy of an animal that once lived in the sea represented by Sheppey's London Clay.
Diagnostic Features
- Anterior crown: Long, very slender cusp showing strong sigmoidal (S-shaped) curvature, particularly in lower-anterior and some juvenile teeth described by Casier; not every tooth position is equally curved.
- Crown-base ornament: Faint, short folds can occur close to the lingual crown base of anterior teeth; in small lateral teeth, folds may appear on the labial basal edge or be organised on the crown heels. Ornament is variable, not a required feature of each tooth.
- Anterior shoulders: Narrow, low basal heels without a consistently developed pair of projecting lateral cusplets; these differ in extent from the broader lateral-tooth shoulders.
- Anterior root: Two slender root branches with a lingual protuberance divided by a median groove containing the nutritive foramen.
- Lateral-tooth variation: Lateral teeth have more inclined crowns, expanded/elongated basal heels and compressed, broader roots; tooth-position differences must not be mistaken for separate species without supporting characters.
- Differential: The combined slender sigmoidal anterior form, variable restricted basal folds, reduced heels and tooth-position-specific root form should be compared against Anomotodon novus and slender-toothed sharks such as Striatolamia; weak plications alone do not establish the species.
- Identification limit: A detached cusp without basal crown and root cannot reliably separate A. sheppeyensis from other gracile lamniforms. Museum comparisons should match tooth position as closely as possible.
Fossil Details
Similar Species
Recorded Fossil Sites
London Clay Formation
Diagnostic Sources
- Casier, E. (1966). Faune ichthyologique du London Clay. 496 pp.. Trustees of the British Museum (Natural History), London View reference
- Ebersole, J.A.; Cicimurri, D.J.; Stringer, G.L. (2019). Taxonomy and biostratigraphy of the elasmobranchs and bony fishes (Chondrichthyes and Osteichthyes) of the lower-to-middle Eocene (Ypresian to Bartonian) Claiborne Group in Alabama, USA, including an analysis of otoliths. European Journal of Taxonomy, 585, 1–274 View reference
References
- Casier, E. (1966). Faune ichthyologique du London Clay. 496 pp.. Trustees of the British Museum (Natural History), London View reference
- Ebersole, J.A.; Cicimurri, D.J.; Stringer, G.L. (2019). Taxonomy and biostratigraphy of the elasmobranchs and bony fishes (Chondrichthyes and Osteichthyes) of the lower-to-middle Eocene (Ypresian to Bartonian) Claiborne Group in Alabama, USA, including an analysis of otoliths. European Journal of Taxonomy, 585, 1–274 View reference
- Rayner, D.; Mitchell, T.; Rayner, M. (2009). London Clay Fossils of Kent and Essex. 228 pp.. Medway Fossil and Mineral Society, Rochester, Kent View reference
- Ward, D.J. (1980). The distribution of sharks, rays and chimaeroids in the English Palaeogene. Tertiary Research, 3(1), 13–19 View reference