December 2003
Jane” Gets $1 million Gift
US Representative Don Manzullo announced that the federal government will pay Burpee Museum in Rockford $1 million. $900,000 of this will go toward the exhibit hall for “Jane” at the Museum and the rest goes to Northern Illinois University to develop a partnership with Burpee to collaborate on future research projects. Mike Henderson from Burpee is currently going for his PhD at Northern on “Jane”. A condition of the grant is that Burpee uses local labor to design and build the exhibit.
New Earliest (560 MY) Vertebrate Found in Australia
This new fishlike 26 inch fossil pushes the earliest date of a vertebrate back some 30 MY. It is interesting that the researchers who found the previous earliest vertebrate in China thought that their fossil was so well developed that its ancestors probably went back 555 MY. It is also very big for such an early animal that might be expected to be closer to one inch. It was found in a fossil-rich area of sandstone known as Flinders Ranges. The actual backbone is not visible but the shape suggests one. There is the suggestion of a head and striated muscles. As usual not everyone is convinced. Some think that it looks a lot like the known fossil Kimberella. The fossil was found 10 years ago but its age has only recently been determined.
Do Meteorites Cause Volcanic Eruptions?
Many believe that the impact of meteorites on Earth would cause decompression melting of the crustal rock beneath the crater causing volcanic eruptions. However, a study reported in Geology (Vol. 31,p. 869, 2003) by Ivanov et al. argues that this is not what they calculate. They estimate that the crater would have to be at least 500 km wide before molten rock would reach the surface. That is 2 times the size of the largest craters found on Earth so far. This kind of event is estimated to occur every billion years or so. If the meteorite impacted on land the crater would have to be at least 2,000 km wide to cause such an effect. They argue that even the huge crater 2,000 wide on Mars failed to cause volcanism. It will be interesting to see what scientist who hold to the old theory respond.
K/T Asteroid Not Cause of Dino Extinction?
Gerta Keller of Princeton has been studying the K/T for many years and has concluded that the Chicxulub crater was not the cause of the extinction event because the impact happened 300,000 years before the K/T. She believes that evidence indicates that heavy volcanic activity and a series of impacts caused the great stress that killed off many species. She studies the tiny single-celled foraminifer that fill the oceans and can be used as markers because of their rapid evolution. All species of tropical and subtropical foraminifer were also destroyed at the K/T. They are very different before and after the K/T. Now Gerta has found pre-K/T foraminifer above the Chicxulub debris. She has found evidence of 3 separate impact debris levels in Mexico and surrounding areas – Chicxulub, one at the K/T and a third 100,000 years after the K/T. She also reports that the crater is smaller than the 180 to 300 km and is really 120 km across. She is studying a series of volcanic craters starting 500,000 years before the K/T which she believes cause the biotic stress that built to the K/T extinction. It is an interesting theory.
Biggest Fish Found in UK
This one is certainly a catch worth bragging about! Two students found the bones of a fish 155 MY old that has been identified by experts as Leedsichthys problematicus. It is the biggest and most complete specimen of this fish ever found. This Jurassic fisher had teeth on its gills and probably ate plankton. Its length is estimated as being 22 meters or 72 feet long. This is about twice the size of the largest extant fish – the whale shark. It may be as large as the blue whale of today. By its name you can tell that they had trouble identifying it in the early 1800s when it was first found. The previous biggest specimen called Big Meg filled 20 museum drawers. This new specimen already fills 120 drawers. The fish was known from the Mid Jurassic period only till the Late Jurassic which might have coincided with the rise and then fall of sea levels. They would like to display it when they get it together, but aren’t sure they will be able to find enough space.
Tortoises Provide Proof of Volcanic Activity in Galapagos
The volcano Alcedo is located on the island of Isabela in the Galapagos. This island has five species of giant tortoise living in each of the five volcanoes on the island. Two of the subspecies live in the south part of the island and only number a few hundred individuals each. They were decimated by visiting sailors who used them for food. A more successful group of maybe 10,000 survive on the slopes of the Alcedo volcano where they were less accessible. The DNA from members from these 3 subspecies show that the Alcedo tortoises had 1/3 to 1/5 of the genetic diversity of the other two. They date the mutations found to about 88,000 YA. A volcanologist says that date coincides with a known eruption of Alcedo between 120,000 and 74,000 YA. The researchers found that 82 of the 90 Alcedo tortoises studied descended from the same female. Whether that female was a survivor of the volcano or arrived after the eruption is unknown. This report is in an article by Beheregaray et al in Science (Vol. 302, Oct. 3). Some find this encouraging for the possible success of other animals that become reduced to a very small population.
DNA Study of First Americans Arrival at 18,000 YA
The debate about the first entry of “Americans” continues. A DNA study by Mark Seielstad of Singapore in American Journal of Human Genetics (Sept.) refutes previous mitochondria data indicating a date of 40,000 YA. They found that their date of 14,000 YA agrees with the archaeological data also. A new mutation was discovered among some Asian, Indian, and Siberian men and also in Native American people indicating that Asians reached the Americas before Europeans. And so the debate continues.
New Jurassic Tyrannosaurid from Portugal –Aviatyrannosaurus
Oliver Rauhut reports in Paleontology (Vol. 46/5) of finding a fragmentary theropod from the Upper Jurassic of Portugal which he has named Aviatyrannus jurassica (tyrant’s grandmother from the Jurassic). The holotype is an almost complete right illium. Other material found nearby include partial illium and ischium and several premaxillary teeth. The only other early tyrannosaurid known is Stokesosaurus from the Morrison Formation here in North America. In 2000 Rauhut attributed this material to Stokesosaurus, but further study showed structural differences. This strengthens the biogeographic connection between the early tyrannosaurids of the Morrison and Portugal in the Late Jurassic. In the Lower Cretaceous they are known from Europe and Asia and by the Late Cretaceous they are known from Asia and North America. Indications also show that tyrannosaurids started out small and only got really big in the Late Cretaceous.
Karen Nordquist, ESCONI Paleontology Study Group
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