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stories they reveal about the past. When thinking of insect fossils, most people naturally envision amber, although some wonderful rock impressions also exist. For us, amber represents the crowning jewel of all fossils because of the unique lifelike appearance of the entombed life forms and its ability to capture extremely small and delicate objects like spider webs and microbes (fig. 2). Amber also transforms insects into gems of breathtaking beauty. Magnified by a microscope and illuminated by an amber glow, the backs of metallic beetles ornamented with striations and pitted with craters become sculptures. The multifaceted iridescent eyes of horseflies peer eternally into the surrounding resin, and one can only imagine what scenes they looked upon millions of years ago. Amber often captures the final throes of life, such as female insects desperately trying to ensure future generations by laying eggs in their amber coffins.

But the ultimate thrill of working with fossils in amber lies in the fact that each piece of amber potentially has secrets to reveal. Victor Hugo wrote, " Where the telescope ends, the microscope begins. Which of these has the grander view?" So you don't have to be a starship captain to "explore strange new worlds " or " go where no man has gone before." You only have to be a biologist with a microscope and an assortment of amber. Every once in a while a nugget will contain a surprise. Perhaps there will be a new species, genus, or even family of organisms previously unknown to science. It might be the first fossil record of an animal or plant, like the oldest bee or grass or even a strange chimeralike creature that is both mysterious and baffling. These discoveries are scientific jackpots that await the paleontologist like a winning ticket in the lottery, and they bring to mind one of our favorite stories, involving an amber dealer and an amber pendant worn to a party by an unsuspecting woman. Since any true amberphile is all too willing to look at any piece of amber to see what treasures lie within, it was only natural for him to examine the pendant. What he saw was amazing—two fleas. Did we mention that fossil fleas are extremely rare and here were two in one piece of amber? The pendant ended up in a museum! This

Figure 2. The preservation of extremely fragile objects, like this Burmese amber biting midge caught in a spider web, is one of the wonders of amber.

just goes to show that any piece of amber jewelry, including any bead in a necklace, can contain rare scientific treasures.

Can you believe that this warm, organic gem began as resin slowly oozing down the bark of an ancient tree millions of years ago? Amber is a fossilized resin, but the processes that turned it into amber are quite separate from those that preserved the insects embedded within. So amber is really a compound fossil repository containing not only evidence of the giant trees from which it came but also the creatures from that paleoenvironment.

After millions of years of being held deep in the earth's embrace or even immersed in the sea, amber from the Cretaceous has surfaced in various deposits around the world. All amber from that period seems to have been formed by an ancient group of conifers, the araucarians (fig. 3). These trees had a global distribution in the Cretaceous as seen by their fossil remains (fig. 4), although they are now limited to a few populations in the Southern Hemisphere.344

In some areas amber is dug from deep within the earth, but in southern Alberta, Canada, Cretaceous amber is strewn over a desolate prairie where wind and rain have scarred the land and released this treasure from imprisonment in coal and shale. When we traveled to those plains in western Canada with Ted Pike, then a doctoral student at the University of Calgary, we helped collect amber nuggets scattered among fragments of lichen-covered dinosaur bones. They ranged in size from teardrops to walnuts, and many were incrusted with a dark oxidized covering.

When you see them lying side by side, the contrast between amber and other fossils becomes apparent (fig. 5). Unlike entire insects trapped in amber, only the bones, teeth, claws, a few eggs, coprolites and footprints of dinosaurs are left for us to interpret. We only had to travel a few miles north to Dinosaur Provincial Park and the famous Tyrrell Museum of Paleontology to see one of the world's largest collections of Cretaceous vertebrate fossils. These were formed after their remains were inundated with mud or sand, infiltrated with waterborne minerals,

Figure 3. Photo of one of the largest living araucarians, a kauri tree, Tane Mahuta, located in the Waipoua Forest, New Zealand. The tree stands 169 ft (51.5 m) tall, has a girth of 45 ft (13.77 m), and is believed to be about 1,500 years old. The combination of height and girth indicates that it contains some 8,634 ft3 (244.5 m3) of timber.

Figure 3. Photo of one of the largest living araucarians, a kauri tree, Tane Mahuta, located in the Waipoua Forest, New Zealand. The tree stands 169 ft (51.5 m) tall, has a girth of 45 ft (13.77 m), and is believed to be about 1,500 years old. The combination of height and girth indicates that it contains some 8,634 ft3 (244.5 m3) of timber.

Cretaceous Distribution of Araucariaceae

Cretaceous Distribution of Araucariaceae

Figure 4. The global distribution of Cretaceous Araucariaceae based on amber, macro or micro plant fossils, or a combination of these. Fossils indicate that these coniferous resin-producing trees occurred worldwide. The isolated triangle at the bottom of the map represents an Antarctica araucarian fossil site.

Figure 4. The global distribution of Cretaceous Araucariaceae based on amber, macro or micro plant fossils, or a combination of these. Fossils indicate that these coniferous resin-producing trees occurred worldwide. The isolated triangle at the bottom of the map represents an Antarctica araucarian fossil site.

and eventually turned into stone. Rarely, when the sediment covering a dinosaur was particularly fine, an impression revealed the texture of the skin.

Plant fossils have a different appeal than amber or bones. While amber has to be polished to reveal hidden treasures and dinosaur remains usually have to be meticulously excavated and transported to a lab for scrutiny, plants in all their glory can be instantly revealed at the collecting site—not that it still isn't hard work. We have spent hours scrambling up hot, slippery cliff faces covered with haphazardly positioned boulders. Despite the perspiration and the need to remain on the lookout for hidden rattlesnakes, the perfect rock sample could make the hunt worthwhile. When turned on the end and split, a sandstone slab would ideally display two plant impressions, one revealing the top and the other the bottom of a leaf surface. Some of these compression

Figure 5. Different fossil types. Top: three Late Cretaceous dinosaur bone fragments; middle: leaf impressions of a Jurassic araucarian (Agathis jurassica) from Australia; bottom left: a Jurassic permineralized araucarian cone (Araucaria mirabilis) from Patagonia, Argentina; bottom right: pieces of Burmese amber.

Figure 5. Different fossil types. Top: three Late Cretaceous dinosaur bone fragments; middle: leaf impressions of a Jurassic araucarian (Agathis jurassica) from Australia; bottom left: a Jurassic permineralized araucarian cone (Araucaria mirabilis) from Patagonia, Argentina; bottom right: pieces of Burmese amber.

fossils may occasionally retain areas of green pigment or even evidence of insect damage. What an elating experience to free a leaf from that stone tomb after millions of years.

Not just leaves, but petrified wood, trees, cones, and even pollen can tell of past forests. The Petrified Forest of the Chinle Formation in Arizona contains the mineralized stumps of arau-carians and even small bits of amber. A trip there gave us a concept of the immense size of the resin-producing trees in the Mesozoic. We were impressed by massive logs up to 200 feet long and 10 feet in diameter. Their condition indicates that they had been transported in rivers for quite a distance before finally being buried and fossilized. These logs are incredibly beautiful— all their tissues were replaced by varieties of quartz, including amethyst and rose quartz. The dominant color, however, is that of jasper and ranges from reds to yellows and browns. Although these araucarian trees are impressive macrofossils, plant microfossils like pollen and spores, while not as dramatic, can often provide a greater amount of information about the types of plants present in the past.

This brings us back to one of the reasons we find fossils so fascinating: each one has a story to tell. From their anatomy we can glean information about lifestyles and habitats. From fossil assemblages, we can deduce facts about animal and plant interactions, the ecology and climate of those past ages, and taken all together, what life was like millions of years ago during a particular time in the Cretaceous. This is what we hope to reveal to you: a picture of life 145.5 to 65.5 million years ago when insects and dinosaurs competed for available food resources, fed on each other, and suffered from parasites and newly evolving diseases. First, we need to explain how physical and biological changes over the course of the Cretaceous would have affected how insects bugged dinosaurs.

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