Tuesday, 13 March 2012

The Oldest Evidence Of Lobsters Living Together

In my last post, I reported on a fossil which preserved the remains of the way an ancient Jurassic ecosystem functioned. These fossils, although incredibly rare, provide clear evidence into the past. Palaeontologists, led by Adiel Klompmaker, a PhD student from Kent State University, have recovered a fossil from Dotternhausen quarry south of Stuttgart, Germany, which shows the oldest known evidence of lobsters living together.

The fossil cluster and a diagram showing the position of the lobsters
This close up of the fossil makes the lobsters a little easier to see
While they are covered in armour, these many legged crustaceans are under constant threat from large predators and live in small clusters for protection. This new fossil find was nearly missed due to its usual preservation. Cracking open a slab of rock, the palaeontologists found a large and complete specimen of the early Jurassic ammonite Harpoceras falciferum.

It was only when they examined the shell closely that they found a series of smaller fossils inside. The Dotternhausen quarry contains a type of rock called gas shale. The shell of the ammonite was so thin that it was translucent, allowing the researchers to see the tiny preserved exoskeletons of three lobsters inside. It was likely that the ammonite died and drifted to the seabed where the soft innards rotted and the lobsters took refuge inside the husk.

It is possible that they were taking refuge from giant marine reptiles whose remains have also been found in the same geological formation. What makes them important is their age. The rocks from the area have been dated to 180 million years old. Previously, the oldest known lobster cluster was just 100 million years old which came from Greenland. These kinds of fossils may not be the most exciting to look at, but they do reveal the origins of characteristics seen in animals today.