Collapse of simple life forms linked to mass extinction 200 million years ago

I don't know how many of you reads alt.sci.planetary, but this appeared there, thought some of you might be interested:

'A mass extinction about 200 million years ago, which destroyed at least half of the species on Earth, happened very quickly and is demonstrated in the fossil record by the collapse of one-celled organisms called protists, according to new research led by a University of Washington paleontologist.'

<URL:http://www.washington.edu/newsroom/news/ 2001archive/05-01archive/k051...>

ERROR in this report: As I have already noted on another list, the Triassic-Jurassic extinction did NOT wipe out the mammallike reptiles (specifically therapsids). Therapsids have long been known from the Jurassic, and it was recently discovered that at least one family of therapsids apparently even made it into the Early Cretaceous.

Very interesting. But could you please call the Cretaceous therapsids by name? I think I remember something about one or two therapsid groups in early Jurassic times, but none from the Cretaceous. Do you know more?

Christoph Kulmann

Christopher,

The therapsid Family Tritylodontidae. Early Cretaceous of Japan. This temporal range extension (forward in time) was published just last year: Makoto Manabe, Paul M. Barrett, and Shinji Isaji, 2000. A refugium for relicts? Nature, 404: 953 (27 April 2000).

Any chance this fossil was reworked? How is the site dated?