Amber is a natural gemstone that is known to contain creatures from million years ago. Typical creatures found on it are plants and insects given that it is created by plant resins.
However, a paleontologist discovered a Cretaceous amber from Myanmar that contains both land and sea creatures. The amber which is 33 millimeters by 9.5 millimeters by 29 millimeters contains marine creatures composed of four sea snails, young ammonite, and four intertidal isopods along with three possible isopods.
The marine animals are trapped side by side with 22 mites, goblin spiders, 12 full grown insects that include 8 flies, 2 beetles, a cockroach, millipede, and a parasitic wasp.
"It is rare to find an aquatic organism in amber, and it is extremely rare to find marine organism in amber, let alone macroscopic marine organisms mixed with intertidal, terrestrial and potentially freshwater aquatic organism" stated by the researchers in their paper.
How come the two different kinds of creatures (land and water animals) ended up in the same amber? Given that there were no signs of soft tissue belonging to either ammonite or gastropod, it is possible that the shells of the two marine animals are lightly abraded and a piece of shell of animal was lost and lead to clogged the opening of the shell with sand, according to PNAS.
Paleontologists extrapolated that the marine animals were already dead and their shells must be tumbled by tides and washed up on a beach. By this situation, the marine animals must be trapped in the amber wherein a blob fell into the water (formation of amber is not possible when the resin is submerged into water).
"The shells may record an exceptionally high, perhaps storm-generated tide, or even a tsunami or other high energy event. Attentively and more likely, the resin fell to the beach from coastal trees, picking up terrestrial arthropods and beach shells and exceptionally, surviving the high-energy beach environment to be preserved as amber," the researchers added.
On the other hand, paleontologists were still unable to find how old the amber is. The uranium-lead dating of zircons in the matrix of volcanic rock where the amber is found is said to be around 98.8 million years old yet the sandstone layer above the amber where the fossilized ammonite was contained is believed to arrive at 113 million years ago. Re-examination of the said ammonite fossil was unable to conduct since no one has ever found it.
The issue on how old is the amber remains a mystery but it can be believed that it is more than 113 years old given that the amber is older than the bed where it is found.
