300 billion times the size
Arthropods and their huge diversity of size
In the great scheme of nature, size matters.
Animals have evolved an incredible diversity of scale, allowing them to adapt to many habitats and find different ways of making a living.
The size diversity of arthropods is especially staggering.
Arthropods make up 80 per cent of all animal species. Among the arthropods are many familiar animal groups...
Insects
Including beetles, bugs, butterflies and dragonflies
Crustaceans
Including crabs and crayfish
Arachnids
Including spiders and scorpions
All arthropods are built to the same basic body plan
The arthropod body plan contains the head, thorax, and abdomen. Segments bear legs, or other jointed appendages, and the exoskeleton moults with growth.
Despite their fundamentally similar structure, arthropods embody a vast range of sizes.
The wasp Dicopomorpha echmepterygis is the world's smallest arthropod.
Dicopomorpha echmepterygis is a parasitic wasp that lives inside the eggs of another insect, the barklouse Echmepteryx hageni.
It is even smaller than some bacteria, with males measuring only 0.127 mm long.
The extinct sea scorpion Jaekelopterus rhenaniae is the largest arthropod ever discovered.
It lived around 410-402 million years ago and is known from fossils found in modern-day Europe. Scientists have estimated that it once reached a total length of 2.3–2.6 metres from head to tail.
Over 300 billion Dicopomorpha echmepterygis could fit into the volume of one Jaekelopterus rhenaniae. This is greater than the size difference between the Sun and the Earth: the Sun is only 1.3 million times the volume of our planet.
The largest arthropod alive today
Dr Leonidas Romanos Davranoglou from the Museum of Natural History explains the huge diversity of sizes we see in arthropods and introduces us to the Japanese Spider Crab (Macrocheira kaempferi), the largest arthropod alive today.
With Dr Leonidas Davranoglou
Visit the Great and small display
Opened between 2022 and 2024, our new displays on biodiversity showcase the variety of life on Earth and consider important questions about preserving this diversity for future generations.
The Great and small display explores the huge size diversity in arthropods using specimens from the Museum's collections.
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