520-Million-Year-Old Fossil Sheds Light on Origin of Gills in Arthropods paleontology science
, a new species of ancient marine arthropod from eastern Yunnan, China, had unique trunk appendages that represent an intermediate stage of biramous limb evolution., showing the nektonic life style; the initial situation of trunk limbs, as flaps associated with weakly sclerotized endopods indicates a swimming rather than fully benthic habit. Image credit: Fulived in what is now China during the Early Cambrian epoch, some 520 million years ago.
“The Chengjiang Fossil Site preserves an ancient underwater ecosystem which included the relatives of some well-known arthropod fossils like trilobites and anomalocarids,” said Dr. David Legg, a paleontologist in the Department of Earth, Atmospheric, and Environmental Sciences at the University of Manchester, and his colleagues.
Modern water dwelling arthropods have biramous limbs, legs that have two parts — one for breathing and one for walking — but how such specialized limbs evolved was a mystery., had swimming flaps that may have doubled as gills. But, until now, paleontologists didn’t know how arthropods made the jump from these specialized flaps to the biramous limbs of modern arthropods.from the Early Cambrian Chengjiang Lagerstätte, China. Scale bars – 2 mm for and 1 cm for others. Image credit: Fu