Recent discoveries in paleontology




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RECENT DISCOVERIES IN PALEONTOLOGY

1998


June 24 Dinosaur-bird link gains support: fossils discovered in China fill in gaps in sequence begun by the first great “missing link” discovery of Archeopteryx (the earliest known bird) in 1860. New fossils are Caudipteryx and Protoarcheopteryx, feathered reptiles the size of turkeys (Globe)
Oct 1 fossil worm burrows push back first appearance of complex animals from 540 to 580 million years
Dec 10 discovery of a nearly-intact fossil skeleton in Africa that looks like Australopithecus, a link between ape and man: 3.2 million years old, probably same species as “Lucy” but found much farther south

1999

Aug. 31 DNA sequencing has permitted the reaarangement of the phylogenetic tree of plants and has established the close relationship of hippos and whales (in the mid-1990s a whole whale skeleton, with feet, turned up in China): phylogenetic branching tree of life was Darwin’s conception

Oct. 29 a group of woody shrubs identified (by DNA sequencing) as progenitors of flowering plants

Oct. 29 scientists discover four distinct layers of evolution in human X chromosome, suggesting that x and y chromosomes were differentiated 320 million years ago


Nov. 4 Discovery (in China) of fishlike fossils that could be the earliest known vertebrates: 530 million years old (previous oldest vertebrate fossil, 480 million years old)
2000

Mar. 16 discovery in China of a fossil monkey (Eosimias) linking the lower (lemurs) and higher primates1


March 27 discovery of a small raptor (fancifully named Bambiraptor) with a large brain, a bird-like wishbone and sternum and winglike arms so long that the animals had to hold them in the air to avoid tripping over them.2

May 2 DNA sequencing of human family tree (and migration patterns from Africa) traced to 10 genetic Adams (via Y chromosomes) and 18 genetic Eves (through mitochrondrial DNA) [two very stable sequences of DNA; mutations occur at predictable rate, permitting dating]. Modern humans left Africa ca 50,000 years ago


May 12 1.7 million year old fossil hominid skulls (in Georgia) may represent first hominids to have migrated out of Africa
June 23 a small feathered reptile (Longisquama insignis) is discovered in central Asia. It’s much older than Archaeopteryx; the feathers aren’t avian and it’s realtionship to birds is uncertain. But if related to birds it casts doubt on the dinosaur-to-bird hypothesis3

2001
March discovery in Kenya of a new hominid species, Kenyanthropus platyops, 3.5 million years old, a more direct ancestor of man than 3.2 million year old Lucy (1974, Australopithecus afarensis)

April a second new hominid species discovered, possibly an even more direct ancestor (Orrorin tugenensis)4

--a fossil theropod found in China linking birds to dinosaurs. The previous such finds had “feather-like traces”; this one has clear down and feathers in a filigree pattern: dromaeo-sauer, a small fast-running dinosaur related to velociraptor.5 Note the high incidence of recent finds in China, which has to do with the development of an extraordinary bed of fossils in Liaoning province, north of Beijing, by a new generation of Chinese paleontologists.6

June --discovery of second largest dinosaur (Paralititan stromeri) in Egyptian desert. At 70 tons, only Argentinosaurus is bigger.

--two new feathered, bipedal dinosaurs discovered in New Mexico (Times, June 19)

October --whale is shown to be descended from a wolf-sized ungulate, related to the Hippopotamus (Times, Oct. 2)

2002


March --discovery (in China) of a horned dinosaur (like Triceratops) but no bigger than a rabbit (130 million years old), the oldest progenitor of Triceratops, demonstrating that the divergence between ceratopsians and parrot-beaked dinosaurs occurred earlier than previously thought (Times, Mar. 26).


1 See story in Time, March 27, 2000, p. 84


2 Time, March 27, 2000, pp. 84-85.


3 John Noble Wilford, “Fossil Disovery Threatens Theory of Birds’ Evolution,” NY Times, June 23, 2000, p. 1.


4 Wilford, “On the Trail of a New More Ancestors,: NY Times, April 8, 2001.


5 Wilford, “Fossil Found in China is Seen as Linking Birds to Dinosaurs,” New York Times, April 26, 2001, page 1.


6 “Chasing the Dragons,” Nature, 31 August 2000, pp. 930-932.



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