Fossil Crabs
Crabs are a relatively common discovery when searching the sands of Folkestone. They are often mistaken for lumps of phosphate, which is abundant in the area. However, once you have identified your first specimen and become familiar with the distinctive patterns, locating additional examples becomes much easier.
Most crabs unearthed in the sand show signs of wear or damage, yet their robust structure often preserves remarkable detail. In most cases, only the carapace is found—likely the result of moulting during growth. On rare occasions, however, a complete specimen may be uncovered, displaying the underside with the pleon and, in some instances, even the limbs.
On this page you will find some of the better examples in my collection currently. There are many different species to be found at Folkestone. For a better catalogue I recommend a copy of "fossils of the gault clay"
Etyus martini
(Mantell, 1844)
This crab species is relatively small, ranging from approximately 4 mm to 40 mm in length, with most specimens measuring around 10 mm. It is readily identifiable by its elongated body—approximately twice as long as it is wide—and a gently curved front margin, giving it a distinctive rugby ball–like shape.
The carapace is heavily ornamented with raised dotting across its entire surface. The lateral edges are rounded rather than sharp. When viewed from the front, the central region presents a shape reminiscent of a martini glass—perhaps a subtle influence in the naming of the species.
Only a small number of specimens have been found with preserved undersides or limbs. Due to its diminutive size, the species often goes unnoticed by collectors, despite being nearly as common as stokesii.
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Find frequency on the foreshore: Uncommon
Notopocorystes stokesii
(Mantell, 1844)
This is among the larger crab species found at Folkestone, with sizes ranging from approximately 10 mm to 50 mm, though most specimens measure around 20 mm. It is readily distinguished by its oval-shaped body, which is noticeably thicker towards the anterior.
The carapace displays a coating of raised, closely spaced dots visible under magnification. A distinctive vertical row of larger raised ornamentation runs from the posterior to the anterior along the dorsal midline, with smaller raised dotting positioned laterally on the anterior portion of the carapace.
Specimens with preserved undersides or limbs are rare. However, this is by far the most frequently encountered crab species at Folkestone, with at least a partial specimen typically found on each visit.
Find frequency on the foreshore: Common
Notopocorystes serotinus
(Wright & Collins)
This is among the larger crab species found at Folkestone, with sizes ranging from approximately 10 mm to 50 mm, though most specimens measure around 20 mm. It is readily distinguished by its oval-shaped body, which is noticeably thicker towards the anterior.
The carapace displays a coating of raised, closely spaced dots visible under magnification. A distinctive vertical row of larger raised ornamentation runs from the posterior to the anterior along the dorsal midline, with smaller raised dotting positioned laterally on the anterior portion of the carapace. This species is identified by an extra tubercle either side of the mesogastric tubercle.
Specimens with preserved undersides or limbs are rare. These are only found in the upper beds and as such are much rarer to find than the similar stokesii.
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Find frequency on the foreshore: Uncommon
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Joeranina broderipii
(Mantell, 1844)
This is among the larger crab species found at Folkestone, ranging from approximately 10 mm to 50 mm in size, though most specimens measure around 20 mm.
It is easily recognised by its oval-shaped body, which is thicker towards the anterior. The species closely resembles N. stokesii in overall shape but lacks almost all ornamentation. The carapace is smooth throughout, with surface detail limited to shallow grooves along the sides and anterior margin. Well-preserved specimens without erosion reveal a row of small spines at the anterior edge of the carapace’s dorsal surface.
Because of these similarities, it is often mistaken for a water-worn or eroded N. stokesii. Collectors are encouraged to review their Folkestone crab specimens, as this species is comparatively rare and may be overlooked.
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Find frequency on the foreshore: Rare
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Necrocarcinus labeschii
(Eudes-Deslongchamps, 1835)
This is a medium-sized crab species found at Folkestone, with specimens ranging from approximately 10 mm to 50 mm in size, though most are around 20 mm. It is readily identified by its nearly circular carapace, which widens slightly towards the anterior. The surface is generally smooth apart from prominent raised tubercles on the dorsal side.
One particularly notable specimen, to the best of current knowledge, represents the largest example of this species recorded from Folkestone. A comparison between this specimen and a smaller juvenile—illustrated above—reveals that the smaller individuals exhibit more pronounced dorsal tubercles, whereas these features are greatly reduced or almost absent in the larger example.
This crab is highly sought after among collectors. Over eight years of searching, only three specimens have been recorded by the myself, highlighting its rarity.
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Find frequency on the foreshore: Very rare
Dioratiopus depressus
(Carter)
The carapace is broad with distinctly rectangular lateral margins, exhibiting a width almost greater than its length. It shows no transverse arching and remains nearly flat along the longitudinal axis.
Unlike spinosus, it lacks an anterolateral spine. The surface features only faint grooves, and the rostrum is short. The dorsal surface appears nearly smooth, even under magnification.
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This crab was a very welcomed find, I have not even found a partial on my previous hunts and its one of the rarest crabs in collection currently
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Find frequency on the foreshore: Very Rare
Dioratiopus spinosus
(Van Straelen)
The carapace is pentagonal in shape, with steep lateral margins and a length exceeding its width. It is gently arched transversely and nearly flat along the longitudinal axis. The rostrum is narrow, sulcate, and prominently produced, tapering sharply downward distally.
The orbital depressions are shallow and obliquely oriented. A long, curved spine arises from the anterolateral margin. The carapace regions are distinctly delineated by well-defined grooves, with a low node present on each protogastric lobe. The dorsal surface is densely covered with fine granulations.
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The specimen described above represents only a partial example; a more complete specimen was later discovered by P. Hadland, with an accompanying image available for reference. Another notable specimen was identified by P. Mannering-Green, distinguished as the only known example preserved with a claw. This specimen has since been transferred overseas for ongoing research and examination.
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Find frequency on the foreshore: Very Rare
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Notopocorystes stokesii with double Kanthyloma crusta
(Mantell, 1844)
Less than 5% of the crabs found at Folkestone contain Kanthyloma crusta, these were a type of parasitic crustacean (similar in look to a woodlouse) that would attach to the branchial region. As they grew the crab carapace would bulge to accommodate the parasite.
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The above specimen is a very rare example as it has two such parasites, something almost never seen.
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Find frequency on the foreshore: Very Rare