Out of the Rock Paleo Festival 2001
Those of us that attended this program in Rockford this weekend had a great time. Lonnie Stark at the Museum set up a table for us and we displayed our Bulletins and the flyer for our Show the following weekend. We talked with a number of people and enjoyed the talks and the Museum immensely. I highly recommend it next year for those of you who missed it.
But on to the show. I will briefly summarize the talks that we attended to give you an idea of what this show is all about. The nice thing was that it was all very informal so that you could chat with the speakers (and get photos and autographs) between the talks. We spent quite a bit of time talking with Karen Chin who will be moving to the University of Colorado this summer to a permanent teaching position. She is the recognized expert on coprolites. When we saw her looking at our ESCONI Mazon Creek books, Jim Fairchild raced over to present her with a gift set. She was delighted.
Niles Eldredge from the American Museum of Natural History spoke twice on Saturday and is a recognized expert on trilobites, horseshoe crabs and evolution. He was co-author with Steven J. Gould of the theory of punctuated equilibrium. He took us through the structure of the trilobite, a member of the arthropods. His attraction to these animals is their interesting and complex anatomy. Luckily their tough shells that were shed often to allow growth are easily preserved over the millennia. The fragile legs are rarely found preserved. The trilobite was long lived being most abundant in the Cambrian/Ordovician and slowly decreasing in species number to its end at the Permian/Triassic boundary. Trilobites had no claws so were not predators. They were filter feeders that used their legs to stir things up. They had a facial suture where they would split open to molt. He reviewed the eight trilobite orders that show an interesting variation of form within each of them. And he talked about the difference between the holochroal eye and the schizochroal eye. The later were enormous and had many separate corneas on each aggregate. The 18 columns of corneas their eye has identify some species. In his first talk Niles went overtime by about 40 minutes, but no one wanted him to stop talking. Actually, I wished that we could invite him to our Paleo meeting next month when we will be talking about the trilobite.
At the end of the day he spoke more generally about evolution, natural selection and the rhythm of life. He and others have now formed a group in Santa Barbara California to study the slower more stable pace of evolution. The new reports of asteroids hitting the earth about 3.5 BYA coincide with the beginnings of life. Did they bring life? Did they bring most of the water now on the earth? We are not sure if there is a cause and effect here. In addition, the snowball theory says that the Earth was totally engulfed in ice several times about 2.2 BYA. 540 MYA during the Cambrian Explosion, all of the modern life forms appeared. This might be explained by the amount of saturated oxygen in the seawater. Over time stasis, speciation, and extinction have played important roles in the story of life.
Dennis Kolata from the Illinois Geological Survey and the University of Illinois at Urbana talked about the Ordovician of 450 MYA in the Rockford area. It was a trip to the Tropics. Using examples of fossils found in local quarries he brought that world to life – trilobites, horn corals, starfish, crinoids, echinoderms, systoids, and gastropods. Illinois at the time was below the equator and islands off the East Coast of the US rammed into it and then drifted away with pieces of it to eventually form Europe.
Two students from the University of Wisconsin, Chris Ott and Laura Buckley presented a very good talk on their explorations of the Hell Creek formation and the dinosaurs that they have found. They have worked with Pete Larson and now have a composite Edmontosaurus and almost enough parts for a Triceratops. They also announced two new discoveries that will be published soon, one a Protoceratops that would be a first for Hell Creek and a possible Avimimus bone. When I spoke with them later, they said that there was even more that they could not yet talk about. We’ll have to keep an eye out for more info on their new discoveries.
Sunday brought out the coprolite specialist Karen Chin who always gives a great talk and loves to intersperse them with humorous word jokes ("Feces Happens"). She gave us a good overall look at animal feces and how she studies them. There are nine agents that work to destroy coprolites (microbial decomposition, rain, desiccation are a few), so it is amazing that any of them survive. However, there was a lot of it (compare the body of an animal to the amount of feces it would generate in its lifetime!). Once again as with bones, rapid burial is needed to assure preservation. Interestingly enough the scat of meat eaters would be easier to recognize because of the presence of phosphate (usually calcium phosphate) from the bones of prey animal ingested. 80% of preserved dung is from fish and only a small amount is from dinosaurs. There are three common features she looks for – fecal shape (sausage shape), phosphatic chemistry, and dietary residues. We can learn a lot about animals and their environment from what they eat and that is why her studies are important. She showed us the only probable known T rex coprolite from Canada that she studied. She concluded that it was "T rexcrement". Her studies on coprolites that show signs of dung beetles were also fascinating. She concluded her talk by assuring us "that it all comes out in the end".
Don Lessem is known as ‘Dino Don’ or ‘Mr. Dinosaur’ spoke about the largest theropods that ever lived. He said that there are about 800 known dinosaurs, many known only by single teeth or bones. T rex was the largest animal for its time about 65 MYA. It was the most advanced animal with only two fingers and smaller arms to help it balance. The arms seemed useless and could not even touch each other. It could not rear up as it had been shown because of the structure of its hip and leg bones. Now there are two new carnivores that could have been larger than the T rex. They are Carcharodontosaurus from Africa (Sereno’s) and Giganotosaurus from Patagonia in Argentina. These two lived at about the same time 100 MYA. This would indicate that the large theropods flourished, then disappeared, and then re-evolved about 70 MYA. Giganotosaurus lived with the humongous Argentinosaurus, the 100-ton plant eater. Don also mentioned the Currie quarry in Argentina where 6 animals have been found together, maybe indicating communal behavior of some sort.
And the final presenter, Jack Horner from the University of Montana, had the largest audience of the Fest. Although he was listed as talking about his new T rex finds, his only comment was that he would not talk about T rex. And he didn’t, except to comment that one of his T rexes was 15% bigger than SUE. Instead he presented a strong argument for the bird-dinosaur connection, which is a controversy still raging today. He emphasized the scientific approach to paleontology that requires the comparison of characteristics to determine relativity. He asked for one characteristic that defined reptiles and none was found. He showed a chart that showed that birds are reptiles, but the argument is whether they arose from dinosaurs or some other archosaur. Birds share more characters with crocodiles than with any other group alive today. And there are some 150 characters that birds share with theropod dinosaurs. Some of them are pubic bone configuration, semi-lunate carpal wrist bone, long middle finger, furcula, anklebone arrangement, 3 toed foot, eggshell, and many more. Dinosaurs have been found brooding on a nest like birds. Naysayers say that these are convergences – all 150 of them?!?! They do not present an alternative. He also discussed his bone histology studies that also strengthen this theory (and may one day help us determine how longed dinosaurs lived). As usual Horner’s talk was well received and it was the perfect end for the weekend.
Dung Beetles
After Karen Chin’s talk at Burpee, I was attracted to a recent article in the February 23 issue of Science by Douglas Emlen at the University of Montana. It was about dung beetles and tried to explain the reasons for the different features they have developed. It seems that these animals also confused Darwin who could not explain the reasons for the placement and size of the horns. In this article it is determined that the beetles pay a price for the big horns they grow, and the price depends on their placement. There are two types of dung beetles – the rollers who roll their dung away and the tunnelers who take it below ground. It is now known that the males use their big horns to protect the female and the young in the dung balls in these tunnels. But horns have a cost and depending on their location something else is weakened. In some where the horns are near the eyes, the eyes are weakened, in some with horns near the antennae, the antennae are reduced, and in others where the horns are on the thorax, the wings may be reduced. This is only true for males with horns and does not correlate for the species where the females have horns. The reason that the nearest organs to the horns are reduced has to do with the need for it. For example, nocturnal beetles need good eyesight so their horns would be away from the eyes. A species that needs to move greater distances to find dung would need to have strong wings, so horns would not grow near them on the thorax. A species that relies more on smell would not want to sacrifice antenna size. The beetles studied are the Onthophagus that have about 2000 species with a range of horn structures. The reduction in nearby organs averaged about 20 to 28%. There are costs of these reductions such as impaired locomotion, greater risk of predation, or impaired immune reaction. These may affect sexual selection and survivability.
An interesting fact sited in the review was that there was one case where 16,000 dung beetles took away a 1.5 kg pile of elephant dung in under 2 hours. They are fascinating creatures and have been around a long time. The dung beetles that picked up after the dinosaurs apparently found a way to survive by picking up the dung of mammals.
Karen Nordquist, ESCONI Paleontology Study Group
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