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Prehistoric 'fish lizard' discovered in Southeast

Posted: Sunday, July 20, 2003

KETCHIKAN (AP) A team of paleontologists researching marine invertebrates near Kake made an unexpected find earlier this month: a 220-million-old marine reptile called an ichthyosaur.

The discovery, along with a recently rediscovered ichthyosaur specimen on Gravina Island near Ketchikan, could help shed new light on how Southeast Alaska formed over time, scientists say.

Researchers from the United States and Canada found the remains of one or more ichthyosaurs on an island in Keku Strait near Kake this month, according to Christopher McRoberts, a team leader and an invertebrate paleontologist from the State University of New York at Cortland. Kake is on the northwest shore of Kupreanof Island, about 70 miles east of Sitka.

The specimens had an estimated length of about 10 feet and are about 220 million years old from the Upper Triassic Period, he said. Ichthyosaur literally means ''fish lizard'' in Greek.

''We were very surprised. They've never been reported in the area,'' McRoberts said.

Ichthyosaurs are a group of marine reptiles that lived in the Triassic, Jurassic and Cretaceous periods of the Mesozoic Era. They are not dinosaurs, but lived when dinosaurs roamed the earth, McRoberts said.

The animals had streamlined bodies, a fish-like tail, a skull with a large eye opening and narrow jaws with peg-like teeth that they used to feed mostly on squid-like organisms. They resembled the unrelated dolphin, and might have given birth to live young. Some were 65 feet and longer.

Ichthyosaur remains have been found in similar age Triassic rocks in British Columbia, Nevada, California and Oregon. They also have been found in the Brooks Range, the Wrangell Mountains and on Gravina Island in Alaska.

The team left most the Kake ichthyosaur remains in place, giving a few pieces to the Organized Village of Kake, the community's tribal government. The researchers held an informal town meeting in Kake to show residents the fossil and explain the importance of the find, McRoberts said.

Michael Orchard of the Geological Survey of Canada, McRoberts, Peter Ward of the University of Washington, SUNY undergraduate student Emily Hopkin and Erik Katvala, a graduate student from the University of Montana, were part of the team that made the Kake discovery.

They were looking for fossil mollusks and extinct fish-like organisms called conodonts in Kake and on Gravina Island to determine biotic diversity and extinction patterns of marine invertebrates of the Triassic, McRoberts said.

''The (ichthyosaur) was sort of the bonus,'' he said. ''None of us work in that (scientific) area, so it probably should be left for someone who does.''

Gary Williams, executive director of the Organized Village of Kake, said Kake residents were excited to hear about the discovery.

''It's pretty doggone neat,'' he said. ''We want to approach it cautiously and do what's right.''

Meanwhile, a group from the Ketchikan area and Oregon State University tracked down an ichthyosaur on Gravina Island on July 5 that was documented by Henry Berg of U.S. Geological Survey in the late 1960s. Tongass National Forest geologist Jim Baichtal, who helped plan the trip, said the Gravina fossil is about a foot long, and is a type of ichthyosaur called a mixosaurus.

''Since 1969, a portion of the vertebrate column as eroded away,'' he said. ''You can see all of the ribs, the bones of the fluke or the fin and part of the tail column in the rock. The head is missing. It may be in a rock adjacent to it.''

Because the fossil is eroding, Baichtal has invited a team of experts to help remove and preserve it this summer. He has applied for state excavation permits, as is required by law, and has talked with the Tongass Historical Museum about displaying it in Ketchikan.

''It's too much of a treasure to lose,'' he said.

Robert B. Blodgett, an invertebrate paleontologist at Oregon State University in Corvallis, said the Kake discovery and the Gravina find are generating excitement and e-mail among scientists who study Alaska's Mesozoic rocks. He plans to visit Southeast Alaska later this summer to look at the fossils.

''This is exciting stuff, especially in terms of plate tectonics and biogeography,'' he said.

By studying the biogeography of an area, scientists can learn what type of animals used to live where, Blodgett said. Such work also lends clues about what the climate used to be, he said.

As more research is done on Southeast Alaska's fossils, scientists will gain a better understanding of how the region formed and moved, he said. Scientists believe what's called the Alexander terrane in Southeast Alaska was originally part of Siberia or Russia, he said.

''We have found some of the same fossils on Prince of Wales Island as in the Ural Mountains and part of Siberia,'' he said. ''It should help add more light on where was the Alexander terrane?''



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