Palaeorhincodon dartevellei
Palaeorhincodon dartevellei
Common Name: Whale Shark
Order: Orectolobiformes
Family: Rhincodontidae
Genus: Palaeorhincodon
Geological Age: Ypresian
Summary
Palaeorhincodon dartevellei was an extinct member of the whale shark family that lived during the Early Eocene. Despite belonging to the same family as the enormous living whale shark, it is known mainly from tiny teeth only a few millimetres high.
The teeth have a narrow pointed central cusp that curves strongly backwards, normally accompanied by one pair of small side points, although a second pair may occasionally occur. The crown is smooth and the short central part of the crown extends slightly down over the root.
Teeth from the front and sides of the mouth differ noticeably. Front teeth are straighter and have very small side points, while lateral teeth lean sideways and have longer, more obvious cusplets.
The species is rare in the London Clay, including the Isle of Sheppey. Its extremely small size means that teeth are much more likely to be discovered through careful searching of fine material than during ordinary surface collecting.
Geological Age & Range Notes
Ypresian. Older literature extends the species into deposits described as Thanetian, but modern revisions recognise the Thanetian Palaeorhincodon material from Morocco principally as the separate species P. daouii.
Arambourg originally reported P. dartevellei from lower Palaeogene deposits beginning with what he regarded as Thanetian levels. Modern treatments distinguish P. daouii from the Thanetian and P. dartevellei from the Ypresian, making an Early Eocene Ypresian age the safest range to use for this species.
Known Localities
Diagnostic Features
Key features used to recognise and identify this species:
- Teeth are very small, generally around 3–4 mm high, although individual specimens may vary.
- The middle of the tooth forms a narrow, cone shaped central point.
- The main point is noticeably curved backwards towards the inside of the mouth. This curvature is one of the most characteristic features when the tooth is viewed from the side.
- The central point is generally smooth, without serrations or strong surface decoration.
- There is usually one small pointed cusplet on each side of the central cusp.
- Some teeth can develop two pairs of side cusplets, particularly teeth from farther around the jaw.
- The side points are cone shaped and sharply pointed on lateral teeth.
- On teeth from near the front of the mouth, the side points can become very short, rounded or almost disappear completely.
- The cutting edges are sharp and smooth rather than serrated. Recent comparisons within the genus recognise the developed sharp cutting edges of P. dartevellei.
- On the front face of the tooth, the centre of the crown extends slightly down over the root as a short, thick, rounded projection.
- This projection is relatively small and does not hide most of the root. The two sides of the root remain clearly visible.
- The root is broad compared with the narrow crown and is approximately heart shaped when viewed from underneath.
- The root consists of two rounded lobes.
- A deep groove separates the two root lobes on the inside of the tooth.
- A central opening is present within this groove, representing one of the original blood and nerve supply openings of the tooth.
- Teeth from the front of the mouth are generally more upright and symmetrical.
- Teeth from farther around the side of the mouth become slightly tilted, with larger and more obvious side cusplets and a broader root.
Quick Identification
Look for:
tiny tooth + narrow central point strongly curved backwards + one or sometimes two pairs of small side points + smooth crown + short rounded projection over the root + broad two lobed root with a deep central groove.
Identification Notes
he first thing to remember with Palaeorhincodon dartevellei is its very small size.
Although it belongs to the whale shark family, its teeth are tiny. Arambourg’s original specimens were only around 3–4 mm high, and a London Clay specimen from Sheppey is illustrated at approximately 5 mm.
Look at the central point from the side
The main cusp is not simply an upright triangle.
It should show a noticeable backwards curve, particularly when viewed from the side.
A useful identification photograph should therefore include a side view, because this curvature may be much less obvious in a straight front photograph.
Look at the side points
A typical tooth has:
small side point + narrow central point + small side point.
However, the size of these cusplets changes considerably depending on where the tooth sat in the mouth.
Front teeth have:
- a more upright central point
- very small or almost invisible side points
- a compact rounded root
Lateral teeth have:
- a central point leaning towards one side
- longer and sharper side points
- occasionally two pairs of cusplets
- a wider and more spread out root
This variation was already recognised in Arambourg’s original description.
Check the root
The root is extremely useful for identification.
Viewed from underneath, it has a roughly heart shaped outline, formed by two rounded lobes.
A deep groove runs between the lobes, with a central opening associated with the original tooth’s vascular supply.
A specimen consisting only of the crown is therefore considerably harder to identify confidently than a complete tooth.
The crown should be smooth
The crown should not have:
- serrations
- strong vertical ridges
- heavy wrinkles
- complicated surface ornamentation
The overall appearance is relatively clean and smooth, with the shape of the cusp and cusplets providing most of the useful identification features.
Similar Species
Palaeorhincodon wardi
This is probably the most important comparison within the genus, particularly for European Eocene material.
Palaeorhincodon wardi has a more heavily built tooth. Its main cusp is comparatively broad and robust, and the tooth as a whole tends to look lower and thicker. Its root is also broad, with a very strongly developed central inner swelling.
In comparison, P. dartevellei has:
- a narrower, more cone shaped central cusp
- stronger backwards curvature
- generally more clearly separated pointed side cusplets
- a relatively short rounded central crown projection
- a more delicate overall appearance.
Because P. wardi itself occurs in European Eocene deposits and is recorded from the London Clay, age and locality alone should not be used to distinguish the two.
Palaeorhincodon daouii
Palaeorhincodon daouii is an older member of the genus known particularly from the Thanetian of Morocco. Modern work separates it from the Ypresian P. dartevellei.
Because both are very small Palaeorhincodon teeth, detailed crown and root morphology should be used alongside geological age. For poorly preserved teeth from deposits close to the Palaeocene Eocene boundary, identifying only to Palaeorhincodon sp. may be safer.
Palaeorhincodon fialhoi
This species was described in 2025 from the Late Miocene of Portugal and greatly extends the known history of the genus.
It differs from P. dartevellei particularly in having:
- blunter, more rounded cutting edges
- much less strongly developed side cusplets
P. dartevellei instead has sharper cutting edges and better developed side cusplets.
The enormous age difference also makes confusion unlikely for correctly provenanced London Clay material.
Other small orectolobiform sharks
Several small carpet shark teeth can have a central cusp and lateral cusplets.
For P. dartevellei, concentrate on the complete combination of:
very small size + strongly backwards curved narrow cusp + small conical side points + short rounded front projection + heart shaped two lobed root with a deep groove.
A specimen lacking the root or side cusplets should be identified more cautiously.
References & Literature
Arambourg, C. (1952). Les vertébrés fossiles des gisements de phosphates (Maroc–Algérie–Tunisie). Notes et Mémoires du Service Géologique du Maroc, 92, 1–372.
Original description of the species as Squatirhina dartevellei, including detailed descriptions of anterior and lateral teeth and its North African distribution.
Herman, J. (1974). Compléments paléoichthyologiques à la faune éocène de la Belgique. 1. Palaeorhincodon, genre nouveau de l’Eocène belge. Bulletin de la Société Belge de Géologie, 83(1), 7–13.
Establishes the genus Palaeorhincodon and describes P. wardi, an important comparison for P. dartevellei.
Noubhani, A. & Cappetta, H. (1997). Les Orectolobiformes, Carcharhiniformes et Myliobatiformes des Bassins à phosphate du Maroc (Maastrichtien–Lutétien basal). Palaeo Ichthyologica, 8, 1–327.
Major systematic revision of Moroccan Palaeogene sharks; recognises P. dartevellei as valid and describes P. daouii.
Vassilyeva, O.N. & Malyshkina, T.P. (2008). Biostratigraphy and palaeobiota changes during Palaeocene–Eocene transition in the Pershinsky pit, Middle Trans-Urals. Lithosphere, 2008(1), 18–50.
Documents Palaeorhincodon within shark assemblages around the Palaeocene Eocene transition.
Rayner, D., Mitchell, T. & Rayner, M. (2009). London Clay Fossils of Kent and Essex. Medway Fossil and Mineral Society, 228 pp.
Important illustrated reference for London Clay fossils, including Palaeorhincodon dartevellei.
Cappetta, H. (2012). Chondrichthyes: Mesozoic and Cenozoic Elasmobranchii: Teeth. Handbook of Paleoichthyology, Volume 3E.
Major modern reference for fossil shark dental morphology and classification.
Boulemia, S. & Adnet, S. (2023). A new Palaeogene elasmobranch fauna (Tebessa region, eastern Algeria) and the importance of Algerian Tunisian phosphates for the North African fossil record. Annales de Paléontologie, 109(3), 102632.
Modern record of P. dartevellei from North African Palaeogene deposits.
Cooper, J.A. et al. (2024). The rise and fall of shark functional diversity over the last 66 million years. Global Ecology and Biogeography.
Includes P. dartevellei in an analysis of fossil shark tooth functional diversity and interprets the species as an extinct planktivorous whale shark.
Landau, B.M., Hovestadt, D.C. & Silva, C.M. da (2025). A new chondrichthyan fossil assemblage from the Miocene Cacela Formation at Albufeira, Algarve, Portugal. Zootaxa, 5724(1), 1–66.
Describes Palaeorhincodon fialhoi and provides useful modern comparisons between the recognised species of Palaeorhincodon, including P. dartevellei.