Saturday, 21 January 2012

A New Species Of Fossil Crab Named After The King Of Pop

The fossil carapace of Mesoparapylocheles
. The white scale bar at the
bottom indicates one millimetre
Arthropods are some of the most common organisms on Earth. Throughout Earth history, these creatures have formed a big part of the food chain, occupying all niches of life from tiny plankton to giant, predatory sea scorpions. They divided into five groups on the basis of their morphology. There are the molluscs, snails; insects, beetles; arachnids, spiders and scorpions; myriopods, such as centipedes and millipedes; and finally the crustaceans.

Parapylocheles scorpio, the only living relative of the
recently discovered Mesoparapylocheles michaeljacksoni
Crustaceans have either 10 or 12 legs and are usually covered in thick armour. They are the most ancient arthropods still in existence (only trilobites are older and they, of course, are extinct) and some of the most diverse, both today and in the fossil record. Many different species are named every year. Some have plain names, while others are a little more exotic. The most recent crustacean discovery is the latter. On June 25, 2009, a team of palaeontologists excavating in the Pyrenees in Spain, found the remains of a
mysterious creature.

The fossiliferous rocks were situated in an abandoned limestone quarry near the town of Koskobilo in the Spanish province of Navarra. The team were led by Adiel Klompmaker from the Department of Biology at Kent State University. The rocks are the remains of a 100 million year old, Cretaceous era coral reef that once covered hundreds of square kilometres of ocean floor that would eventually become Spain. The rocks from the region contain a vast variety of corals and sea urchins. However there is also a wide variety of crabs.

The new partial fossil they discovered was small, less than a centimetre in length, consisting of a single thorax with no legs or tail. A comprehensive comparison with other known fossil crabs from the time did not bring up a match. Further analysis led the team to conclude that it was a new species: a hermit crab most closely related to Parapylocheles scorpio, a species of pylochelid crab. The only remaining question was what to call this new species.

Later that day, the team were meeting in a restaurant in the city of Alsasua. They saw on TV that the pop legend Michael Jackson had died the same day. They decided to name the new crab in his memory, deciding upon Mesoparapylocheles michaeljacksoni. The discovery is a rare one as hermit crabs can only be distinguished from true crabs by a part of the shell known as the shield. Less than 12 have been discovered world wide, meaning that a great deal of their evolutionary history is unknown.