Fossils and prehistoric remnants
About:
We have a number of fossils, casts and preserved remnants of different animals across the prehistoric period. The majority of our fossils are reptiles and fish found in the Devonian period (415-360 million years ago)- which is known for its abundance and diversity of fish.
We also have a few prehistoric bird, mammal and invertebrate specimens.
How are fossils created?
Fossils are the preserved remains of plants and animals whose bodies were buried in sediments (sand, mud, silt etc) underwater in ancient seas, lakes and rivers.
For a fossil to form, sediment must cover the organism quickly. The sediment protects the remains from scavenging animals, erosion and decay. The surrounding sediment thickens and over time turns to rock from the immense pressure of the building layers of sediment and water on top of the fossil.
Over time all organic matter decays or is dissolved by ground water- leaving behind a cavity/space resembling the original shape of the organism like a natural mould. This mould is filled by water rich in minerals which are deposited inside and crystalise, forming the fossil which has the same shape of the original organism but in far less detail.
Diagram illustrating the process of a triceratops decaying, getting washed into a body of water, buried and fossilised , then recovered.
What are the different types of fossils?
Most often, fossils include hard tissue like bones, teeth, shells and wood, since soft tissue usually rots away and is rarely preserved. But footprints and other marks left behind can fossilise, too.
There are 3 main types of fossils:
Trace fossils:
Specifically for animals, these fossils provide evidence the animal existed and gives hints to its behaviour. Trace fossils are usually tracks/footprints, burrows, or coprolites (fossilised faeces).
Mineralised fossils:
These are formed when organic matter in remains is gradually replaced with minerals, turning them into 'rock', such as in the diagram of the triceratops above.
There are different types of minerals, which replace organisms, usually depending on the remains being fossilised. Bone is replaced by a mix of minerals, shells are often replaced with pyrite or opal, wood is usually replaced with silica in a process known as petrification.
Impression fossils:
These are like when you press into a clay mould and it holds the shape. The organism's remains decay completely but they leave an imprint of their external shape in the sediment.
Reptile fossils:
These extinct reptiles roamed the earth alongside the dinosaurs. Our collection includes flying reptiles known as pterodactyls and pterosaurs, and the marine ichthyosaur and plesiosaur. All of our reptile fossils are casts - reproductions of the original fossil
Pterodactyls:
The casts of fossilised pterodactyls in the museum were originally discovered in the Solnhofen limestone in Bavaria, Germany. They are 151 million years old, from the Jurassic Period.
Study of the fossils reveals an interesting adaptation, that the pterodactyl’s wings were formed by a skin and muscle membrane that stretched between its little finger to its hind limbs - similar to modern day bats.
Juvenile pterodactyl
Pterodactylus antiquus
The pterodactyls were generalist carnivores that likely fed on a variety of vertebrates and invertebrates from both land and sea.
The fossil was found in the upper Jurassic lithographic limestone deposits. It is now held at the Carnegie Museum of Natural History, Pittsburgh, USA
Juvenile pterodactyl
Pterodactylus antiquus
These were small winged reptiles, similar in size to bats.
This fossil cast shows the front and back of the animal.
The fossil was found in the Solnhofen Plattenkalk and is kept in the Carnegie Museum of Natural History, Pittsburgh, USA
Adult pterosaur
Scaphognathus crassirostris
With it's name meaning 'fat snout' this reptile had a large head with relatively blunt teeth.
It had a wingspan of 1m, making it one of the smallest of its kind.
The fossil was found in the Solnhofen Limestone and is now kept at Naturmuseum Senckenberg, Frankfurt
Ichthyosaur, Ichthyosaurus communis.
We hold a 60cm plaster cast of the ichthyosaur, Ichthyosaurus communis.
This marine reptile lived in Mesozoic Era, with the fossil dated to the late Triassic (around 250 million years ago)
It's name translates from Ancient Greek to 'fish lizard'.
They resemble modern dolphins, with limbs fully transformed into flippers and a long tail. The ichthyosaur had a long head and pointed jaw, equipped with sharp teeth for catching prey.
Throughout the Late Triassic and Early Jurassic they were particularly abundant and held the status of top predator, until the Plesiosauria took the title in the Late Jurassic/Early Cretaceous.
Hawkin's Plesiosaur:
Thalassiodracon hawkinsi
Thalassiodracon hawkinsi
This is a non-life-sized replica of the lectotype fossil which is on display at the Natural History Museum, London.
The specimen was found in the Lower Lias strata street, Somerset England in the 1830s by Thomas Hawkins.
Thalassiodracon means 'sea dragon' - alluding to the colloquial description Hawkins gave to describe the marine reptile.
The species was alive during the Late Triassic- Early Jurassic period and survived in the seas until the K-T mass extinction event where it died out due to the loss of its prey species.
A full grown individual would measure 1.5-2 meters long, with a broad flat body, short tail and long neck. It was an agile hunter, with it's long neck allowing it to twist and intercept fish quickly.
Fish fossils:
The Devonian Period (415-360 million years ago) is often dubbed 'The Age of Fishes' due to the large abundance and diversity of fish species at this time. The armoured placoderms dominated nearly all aquatic oceans and primitive sharks were becoming widespread. The majority of our fish fossils come from the Mid-to-Late-Devonian period.
Where these fossils were found is somewhat of a mystery, with the majority of specimens lacking collection information, although we have a Placoderm body-cast from Dura Den, Fife, Scotland, and many records of other fossil recoveries from the Devonian link to Northern Scotland.
Dura Den is a gorge 6 miles East of St Andrews that contains well preserved fossils of a number of fish species of lobe-finned fish alongside other groups. The first fossils were located by Mr Spence, a student at the University of St Andrews in 1827.
Below is a list of the fish fossils we hold with some further information about the species:
Pteryicthyodes milleri - a species of placoderm that could reach the length of 30cm. It is covered in bone plates from the tip of its head to it's mid-body. It's eyes are located at the front of its face and and the top of it's head, indicating it was likely a bottom dweller. This fish would have lived approximately 385 million years ago in the Mid Devonian.
Thursius macrolepidotus- a species from the family Osteolepidae which lived in mostly freshwater lakes.
Palaeospondylus gunni- This fish is known as an 'early vertebrate' or 'Gunn's ancient vertebrae'. Scientists struggled to classify this fish suggesting many taxonomies. It was initially classified as an unarmoured placoderm, until a 2022 study concluded it was a stem-tetrapod.
Diplacanthus striatus - a fish part of the class Acanthodii, known as a spiny shark. These fish went extinct in the Permian around 250 million years ago. They are notable due to the development of a jaw to aid hunting, but despite the name, they are not sharks.
Cheiracanthus murchisoni - Another spiny shark - this species was one of the first Devonian fish to be described.
Dipterus Valenciennes - A species of lungfish around 35cm long, that closely resemble modern lungfish. It had tooth-like plates instead of real teeth and unlike its modern relative, had dorsal, caudal and anal fins unfused.
Cephalaspis sp - These fish are possible ancestors to the agnathan vertebrates (jawless fish). It was heavily armoured to defend against predators and had specialist sensory patches along the rim and centre of it's head shield to locate prey burrowing in the mud.
Pteraspis rosata - also known as the wing-shield fish, these were some of the most primitive of the jawless fish (Agnatha). It gets its name from the growths on the side of it's main body shield, which helped provide upward lift, useful for swimming up quickly.
Cladoselache sp - A genus of of primitive sharks that lived in the late Devonian period. It was similar in body shape to modern day sharks however, lacked many modern day traits such as tooth replacement, enameloid teeth or claspers.
Rise and fall of the megladon
In addition to our fish fossils we also have a Megalodon tooth from the giant Carcharocles megalodon.
The megalodon is one of the largest predators to have ever existed, living around 20 million years ago and dominating the ocean for 13 million years until it's extinction.
Reaching sizes up to 18m they had some strikingly large teeth. The edges of these teeth are serrated to help tear meat. Their prey would have included dolphins and even large whales, as seen from fossilised whale bones with bite marks and even broken megalodon teeth preserved.
Prehistoric birds:
Archeopteryx
Within the museum we hold a cast of the Berlin specimen archaeopteryx, Archaeopteryx lithographica. The specimen was discovered in 1874/5 at the Blumenberg quarry near Eichstätt, Germany, by farmer Jakob Niemeyer.
There are twelve specimens of archaeopteryx that have been recovered from the Late Jurassic age (~150 million yeas ago) in the Solnhofen Limestone, Germany. The first discovery of this species in 1861 arose two years after the Publication on Darwin's "On the Origin of Species", and so was heralded as indisputable support for the theory of evolution.
Archaeopteryx is considered the 'missing link' transitionary stage between non-avian feathered dinosaurs, and the birds. Somewhat of an intermediate between reptiles and birds, it has the characteristics of the former (toothed jaw, three fingers with claws, a long bony tail), but also the characteristics of birds (feathers adapted for flight, 's-shaped' wings and a fused clavicle).
The Solnhofen Limestone was deposited in a restricted, hypersaline lagoon where the dead animal fell. These conditions prevented scavengers from accessing the body so the skeleton lay undisturbed and preserved completely. The fine-grain nature of the limestone also allowed the remarkable preservation of imprints of the animals delicate feathers
Terror bird:
One of the most striking specimens in our museum is the Terror Bird, Phorusrhacids, skull cast. This was a prehistoric flightless bird-of-prey that reached up to 3m tall.
They were efficient hunters with a large sharp beak, powerful neck and deadly talons. The terror bird was thought to be a fast runner and caught its prey - usually small mammals - under a clawed foot before delivering deathly blows with its beak.
Prehistoric mammals:
In our archives we have a collection of skeletal remains and casts from different mammals including:
Wooly Mammoth, Mammathus primigenius tooth
Skull casts of the ancestors to modern day horses: Mesohippus, Hipparion and Hippidion
Teeth casts of ancestral horses: Hyracctherium, Mesohippus, Anchtherium, Hipparion in comparison to the modern day horse: Equus
Jaw casts of:
Coal beast
Palaeomastodon
Southern Beast
Stellar's sea cow
Invertebrate fossils:
Invertebrates are often excluded in the fossil record as their soft bodies don't preserve well. However, there are those with hard shells, body armour and other strong structures which do fossilise, giving us an idea of the invertebrate life in prehistoric oceans.
Trilobites
Trilobites form one of the earliest known groups of arthropods. They appeared abruptly in the early Cambrian period (521 million years ago) and survived until the Permian period, where they went extinct (around 250 million years ago).
They leave behind distinctive fossil impressions of their plated exoskeleton, and have been found all over the world. Some burrowed in sediment, while others crawled over the sea floor or swam in open water. They have varying suggested feeding methods ranging from detritus feeders, scavengers or predators.
Ammonites
These were shelled cephalopods that died out around 66 million years ago. They are one of the most common fossils to find, appearing all round the world. They had a coiled external shell similar to that of the modern nautilus, with a soft body inside
In the museum we hold fossils of
Kosmoceras jason from the Mid Jurassic period.
Dactylioceras commune from the Lower Jurassic period
Titans giganticus fossil cast from the Late Jurassic period
These ammonites were giant (as the name suggests) reaching diameters of 1.37m
