Fossils Record Ancient Migrations & Trilobite Orgies
Fossilised "snapshots" provide University of Cincinnati palaeontologist Carlton E. Brett and colleagues with new insights into the behaviour of ancient marine creatures. Brett will present this research March 20 at the regional meeting of the Geological Society of America in Pittsburgh. Few specimens inspire greater thrills among fossil collectors than a complete trilobite. These ancient arthropods - relatives of lobsters, spiders and insects - went extinct more than 250 million years ago, but are sometimes found in beautifully preserved condition. In rare instances, an entire population of trilobites is found fossilised together. Carlton E. Brett finds evidence for ancient environment and behaviour in these mass graves. Read more
A clue to how arthropods - the group of more than a million invertebrate species that includes insects, spiders and crustaceans - evolved their distinctive jointed legs has been discovered in southwestern China. Nicknamed the 'walking cactus' because of its spiny appearance, the Diania cactiformis fossil find is reported in a paper published today in Nature. The animal belongs to the Lobopodia, a now-extinct group of animals resembling worms with legs, which may have been a relative of today's velvet worms. But it is the first species of that group found to have the jointed legs typical of Arthropoda. Read more
Any way you look at it -- by sheer weight, species diversity or population -- the hard-shelled, joint-legged creepy crawlies called arthropods dominate planet Earth. Because of their success and importance, scientists have been trying for decades to figure out the family relationships that link lobsters to millipedes and ****roaches to tarantulas and find which might have come first. In a scientific and technological tour de force that was nearly a decade in the making, a team of scientists from Duke University, the University of Maryland and the Natural History Museum of Los Angeles County have compared genetic sequences from 75 different species to draw a new family tree that includes every major arthropod lineage. Some of the relationships are so surprising that new names had to be coined for five newly-discovered groupings. The work, which was supported by the National Science Foundation, appeared early online Wednesday in the journal Nature. Read more