Tag: David A. Legg
David Legg is a research fellow at the Oxford University Museum of Natural History. His research is focussed mainly at deciphering the interrelationships of fossil and living arthropods, particularly the role fossils play in influencing our understanding of modern groups. As well as phylogenetics, David has a passion for Cambrian arthropods and has spent much of the past five years working on material from the Burgess Shale and describing new species of arthropods, including the bivalved arthropod Nereocaris exilis and the ‘great-appendage’ arthropod Kootenichela deppi.
by David Legg*1
The Palaeozoic era was a time of incredible biological diversification, which saw the origins and establishment of most modern animal body plans and phyla, particularly during the Cambrian explosion, an event which lasted for about 20 million years during the early Cambrian Period (starting about 542 million years ago), and the subsequent Great Ordovician biodiversification event. During this time, there was a lot of ‘evolutionary experimentation’, with many ancient communities dominated by alien-looking creatures unlike any of their modern counterparts. One such peculiar group is the marrellomorph arthropods, roughly 11 species known exclusively from the lower Cambrian (starting about 542 million years ago) to the lower Devonian period (ending about 393 mil
by David A. Legg*1
The arthropods make up a major and highly successful group of animals that includes insects and their kin (hexapods); arachnids and their kin (chelicerates); millipedes and centipedes (myriapods); crabs, lobsters, shrimp and their relatives (crustaceans); and the extinct trilobites. In fact, arthropods are the most diverse, abundant and ubiquitous animal phylum. Members of the group outnumber those of all other phyla on Earth, both in terms of species, with more than 1,200,000 currently described (and a potential 10,000,000 remaining to be described), and in terms of abundance. For example, if you gathered all the world’s Arctic krill in one place, it has been estimated that they would weigh 500 million tonnes! Arthropods are found in all oceans and on al