Fossils widen range of biological burst.Nicholas J. Butterfield's discovery started with a mistake. The paleontologist had planned on studying 1-billion-year-old rocks drilled recently from Canada's Northwest Territories Northwest Territories, territory (2001 pop. 37,360), 532,643 sq mi (1,379,028 sq km), NW Canada. The Northwest Territories lie W of Nunavut, N of lat. 60°N, and E of Yukon. . But when he sent away for the samples, Butterfield wrote down the wrong order number.
While analyzing the rocks under a high-powered microscope, Butterfield was surprised to find a tiny scale from a Wiwaxia, an odd creature from the Cambrian period Cambrian period [Lat. Cambria=Wales], first period of the Paleozoic geologic era (see Geologic Timescale, table) extending from approximately 570 to 505 million years ago. (545 million to 510 million years ago) that he had previously studied.
"It happened utterly by chance, if only because I'm one of the few people in the world who would recognize a Wiwaxia sclerite scle·rite
A chitinous or calcareous plate, spicule, or similar part of an invertebrate, especially one of the hard outer plates forming part of the exoskeleton of an arthropod.
Noun 1. when it floated by," says Butterfield, a researcher at the University of Cambridge in England.
From that initial foul-up, Butterfield found a range of exquisitely preserved fossils that filled the seas soon after the so-called Cambrian explosion Cambrian Explosion
The rapid diversification of multicellular animal life around the beginning of the Cambrian Period, resulting in the appearance of almost all modern animal phyla. -- when the first complex animals evolved. He reports his discovery in the June 9 NATURE.
Scientists had previously found well-preserved fossils from this period in only a handful of sites worldwide, most notably the Burgess Shale in southern Canada. Butterfield's happenstance hap·pen·stance
A chance circumstance: "Marriage loomed only as an outgrowth of happenstance; you met a person" Bruce Weber. now opens the door to new, high-quality finds.
"The type of preservation that we know from the Burgess Shale and thought was relatively limited might be much more widespread than we previously presumed," comments Stefan Bengtson of Uppsala University in Sweden.
The rocks Butterfield studied come from flat-lying deposits near Great Bear Lake that escaped the tremendous heat and pressures generated when mountains form. As a result, the fossils entombed Entombed, or entomb, may refer to:
After dissolving away the stone with hydrofluoric acid hydrofluoric acid /hy·dro·flu·o·ric ac·id/ (-floor´ik) a gaseous haloid acid, HF, extremely poisonous and corrosive.
n a compound consisting of hydrogen and flourine. , Butterfield found an array of different animals, including parts of small crustaceans, which would have measured about 1 centimeter long. Like many modern crustaceans, these Cambrian examples sported tiny bristles for filtering out pieces of plant material in the ocean.
In the past, researchers have suggested that Cambrian animals were jacks-of-all-trades, lacking the specialized features seen among animals today. But the new discovery refutes that idea, Butterfield says. Apparently, crustaceans evolved the apparatus for filter feeding as far back as the early Cambrian.
In today's oceans, filter-feeding crustaceans form a critical link in the food chain by consuming tiny yet abundant phytoplankton phytoplankton
Flora of freely floating, often minute organisms that drift with water currents. Like land vegetation, phytoplankton uses carbon dioxide, releases oxygen, and converts minerals to a form animals can use. . According to Butterfield, the newly found Cambrian crustanceans played the same pivotal role, serving as prey for larger ocean creatures.
These animals may also help explain what sparked the Cambrian explosion. Perhaps the development of filter feeding, he speculates, lit the fuse by expanding the food chain. Butterfield hopes to address such issues this month when he prospects near Great Bear Lake for more of the Cambrian fossils.