Remarkable spider molt found preserved in amber after 99 million years

99 million year old fossil

An extraordinary arachnid fossil, resembling a tarantula molt, has been discovered from Myanmar (formerly Burma), approximately 99 million years old.

In present day Myanmar, ~99 million years ago the land was dominated by a tropical rainforest. Only by chance did a spider molt its exoskeleton (almost certainly a mygalomorph, the ancient lineage that includes today’s tarantulas) and drop it in sticky tree sap, completely encasing it.  Sealed away from oxygen and bacteria, this sap became buried, and over millions of years the resin hardened into amber, preserving microscopic details that would otherwise have vanished forever.  A true miracle of chance!

Close up of pedipalps, used for sensing (touch, taste and smell), holding prey and males even use them for mating.

     Very rarely does a specimen survive with this level of detail. Its form, perfectly preserved, can be read like a priceless book, telling us volumes about what kind of life it lived. Fine sensory hairs used to detect the faintest vibrations in air or soil (called trichobothria) still cover the body and legs. The hooked tarsal claws, perfect for gripping surfaces like bark or silk, remain sharp. The powerful chelicerae that once injected venom and reduced prey to a liquid meal are clearly visible.

Tarsal claws used for gripping are visible at the end of each leg.

We have identified 6 major extinction events in our earth's history.  Each time molding life into new forms. These characteristics have survived the test of time, giving us a translation to their function. A testimony to their success! 

Sensory hairs called trichobothria connected to bowl shaped sockets called bothrium are preserved in excellent detail.

     Imagine this tarantula living among enormous dinosaurs dominating the landscape, in constant danger of being crushed under their lumbering footsteps. Who would have thought it would be the lowly spider to survive the test of time?! The humble spider's descendants still thrive in virtually every terrestrial habitat on the planet today.

     This single piece of amber is more than a beautiful curiosity.  It is a direct, exquisitely detailed message from a vanished Cretaceous world.  Truly a grand contribution to our fossil record!

Article written by: Kevin Huntley