Explore our fossils to see what animals lived in our seas around 100 million years ago.
Many organisms that live today have barely changed their body shape in millions of years and look extremely similar to their ancestors. With the help of Sussex Wildlife Trust we have compared some of our Sussex chalk fossils, which are around 100 million years old, with modern animals that live in UK seas today.
Fossil Sea Urchin, Stereocidaris sceptrifera
Like many modern types living on the seabed, these sea urchins had spines as protection against hungry fish. This fossil is lacking it’s spines but you can still see where they would have been held.
Fossil of Stereocidaris sceptrifera, an ancient species of sea-urchin (or Echinoid). Photo by Bob Foreman
Common sea urchin, Echinus esculentus
Also known as the edible sea urchin. A large, round sea-urchin up to 15cm across with short, strong spines. Usually brick-orange in colour, with white bumps which the orange spines are attached to. Lives amongst seaweed and rocks, where it grazes on algae and small shellfish
Found on rocky shores, particularly around the north and west.
An edible species, eaten particularly in Spain and Portugal.
Fossil fish, Ctenothrissa radians sp.
Fossil fish, Ctenothrissa radians sp., this is a rare complete example of this beautiful scaly fish which was found by Charles Potter in the late 19th Century.
Black seabream, Spondyliosoma cantharus
The black sea bream, also known as a Porgy, is an omnivorous fish, eating seaweeds and small invertebrates.
Black sea bream breed in the Kingmere Marine Conservation Zone in Sussex between April and May. The males excavate a small shallow in the seabed, moving the gravel or sand around the edge to create a sort of crater into which the female lays her eggs. The male then protects the eggs until they hatch. He will fan them with his tail to keep them clear of sand or debris and wards off hungry predators, including smaller bream, wrasse and even whelks!
How to identify:
A large silvery fish, with an oval shape. Shaded bands running along the length of the upper flanks. It has a long single dorsal and anal fin and a small mouth. The tail is large and forked displaying a black band on it, most obviously noticeable on juveniles.
Juveniles usually have numerous broken yellow stripes running along the body. Spawning males are nearly completely black in colour, except for vertical white bars.
Found off south west Britain the Irish Sea and the English Channel.
All black sea breams are born female! They change to males when they reach 30cm. All fish over 40cm are male.
Lobster, Palaeastacus dixoni
This rare fossil lobster was found in the Lower Chalk, Clayton, East Sussex and is from the Upper Cretaceous era. It has been preserved in wonderful detail. First drawings of this fossil appeared in scientific journals in 1850. Collected by Henry Willet.
Common Lobster, Homarus gammarus
A large crustacean, that grows up to 1 metre long, although more typically to about 50cm in lenght. Lobsters are a deep purplish-blue colour, with red antennae. They live in crevices and caves amongst rocks from the low tide mark and deeper. Their first pair of legs have massive grabbing pincers.
How to identify:
Unmistakeable: other species of lobster are smaller and not the same colour
Found all round our coasts.
Lobsters are nocturnal, hiding during the day in their caves.
Who did these unusual teeth belong to?
With the help of Sussex Wildlife Trust we compared some of our fossil animal teeth from 85 million years ago to jaws of animals that live in UK seas today.
Shark fossil teeth, Ptychodus sp.
Originally this ray-like shark would have used a battery of such teeth for crushing molluscs and crustaceans.
These teeth look quite similar to a tropical species of ray’s teeth – the Cow nosed ray, however these live in tropical shallow seas. The UK species of ray that we have chosen as an equivalent is the Thornback ray.
Thornback Ray, Raja clavate
Thornback rays are regularly seen by divers. They have flattened bodies covered in blotches of colour to help them camouflage into the sand or mud or gravel. They have a long thorned tail. The males are smaller than the females.
How to identify:
Flat bodies with yellow and brown patches on their backs. Long thorny tail and protruding eye sockets.
Found all around the UK coast.
Females can lay up to 150 egg cases every year. When the babies hatch, these cases are often washed up onto the beach.
Pipe fish jaw
These teeth would have belonged to a long-snouted slender fish, one of many similar bony fish that lived in the Chalk Seas of NW Europe.
Greater Pipefish, Syngnathus acus
The pipefish has a long, segmented body, about 45 cm long. It lives in seaweed and seagrass and feeds on small prawns and mysid shrimp.
How to identify:
Thin segmented body with a long snout and a hump just behind the eyes
Commonly seen around the southwest coast and welsh coastlines.
Just like seahorses, the males (not the females) look after the eggs in a brood pouch until they are ready to hatch.
…and finally we couldn’t resist adding our favourite sea creature which is protected in our Sussex Marine Conservation Zones…
Short-snouted seahorse, Hippocampus hippocampus
Seahorses prefer to live in seagrass and shallow estuaries.
How to identify:
Distinctive horse like head with snout and a curling tail which is uses for holding onto things
Has been recorded along the south and southwest coasts of the UK.
Seahorses usually mate for life and perform a courtship dance with their partner every morning. The male seahorses get pregnant and give birth to the young.
View more Monster Jaws from the Booth Museum’s in our Monster Jaw gallery
Ray-finned fish (Actinopterygii) evolved over 400 million years ago and are so-called because their fins have a web of skin between several spines. Today, they are the most diverse group of vertebrates with more than 30,000 species which is around half of all living vertebrates on Earth.
The specimens in this gallery are around 85 million years old. By this time, evolution had produced many sorts of fish, types like these being similar in many ways to modern fish. Many specimens of these species have been found which tell us that they probably swam in large schools.
Lobsters swam in our ancient warm Sussex seas around 100-85 million years ago. Lobsters are grouped within the Crustaceans which include crabs, shrimps, prawns and barnacles. They first evolved in the Cambrian period around 509 to 497 million years ago. Click the images to discover more.
Sea stars, sea lilies and sea urchins are all Echinoderms. The name Echinoderm comes from the Greek word meaning ‘spiny skin’. They first appeared in the fossil record in the early Cambrian period around 542-488 million years ago. The fossils in this gallery are between 100 – 85 million years old.
Sussex covered by an ancient sea
Did you know that 100 million years ago the whole of the UK was covered by a warm ocean? Only the tops of the Scottish mountains would have poked above sea-level.
How do we know this? What lived in this warm shallow sea covering Sussex? How does it compare to now? We can use the Booth Museum’s important collection of fossils from the Cretaceous period to find out more.
How do we know that Sussex was covered by a warm sea? The answer lies in the familiar white cliffs of the South Coast – Beachy Head, The Seven Sisters and Dover. These cliffs are all made of a rather special rock. Chalk.
But what is chalk?
When you hold a small piece of chalk in your hand from a walk along the South Downs, you are holding the remains of millions upon millions of microscopic marine plants called algae.
These marine plants thrived a in a warm sea that was 200 to 300 metres deep and covered the whole of the South Downs and most of the UK. The only part of the UK you would have been able to see 100 millions years ago would have been the highest peaks of the Scottish mountain range.
The cell walls of these plants were strengthened with a skeleton made of hard plates of calcium carbonate which, after the death of the algae, slowly sank and built up on the sea floor. Layers upon layers of these skeletons built up to form what is now the South Downs and the famous chalk cliffs.
Discover the animals that lived in the seas 100 million years ago in our fossil galleries.
Unique chalk habitats
The chalk has created rare habitats including chalk reefs which are home to an abundance of wildlife.T he Beachy Head West Marine Conservation Zone, which runs from Brighton Marina to Beachy Head, is a wonderful chalk reef. It is home to threatened species including blue mussel beds and short-snouted seahorses. Read our Rockpooling guide to find out more about what you can spot in Beachy Head West rockpools.