WEBVTT - Special Episode: Coprolites! 0:00:43.600 --> 0:00:47.400 Hi, I'm Aaron Welsh and this is this Podcast Will 0:00:47.479 --> 0:00:50.760 Kill You, and you're listening to the latest episode in 0:00:50.800 --> 0:00:53.840 our mini series of bonus content that we've been releasing 0:00:53.880 --> 0:00:57.120 over the past couple of months. We're nearing the end 0:00:57.160 --> 0:01:00.360 of these bonus episodes for now. We've got just one 0:01:00.360 --> 0:01:03.560 more planned after this, but that doesn't mean that we 0:01:03.640 --> 0:01:07.120 won't come back with more someday. In fact, we'd love 0:01:07.200 --> 0:01:10.400 to do that because these episodes have been so much 0:01:10.480 --> 0:01:12.840 fun and they are such a great way to explore 0:01:12.880 --> 0:01:15.560 even more deeply a topic we covered in our regular 0:01:15.600 --> 0:01:19.640 season episode. For instance, we've been able to dig deeper 0:01:19.760 --> 0:01:22.440 into the world of the epstein bar virus after our 0:01:22.520 --> 0:01:27.520 multiple sclerosis episode, learn about how koalas are impacted by chlamydia, 0:01:28.120 --> 0:01:31.880 understand more about the stigma and discrimination experienced by some 0:01:31.959 --> 0:01:32.720 people living with. 0:01:32.680 --> 0:01:37.119 Hepatitis B, and so much else. In this week's episode, 0:01:37.200 --> 0:01:39.480 we're deviating a bit more from. 0:01:39.280 --> 0:01:42.760 Our regular episode topic than we usually do, but I 0:01:42.800 --> 0:01:45.760 think that makes it all the more exciting because this 0:01:45.840 --> 0:01:49.520 bonus episode covers something that Aaron and I have frequently 0:01:49.720 --> 0:01:53.320 mentioned and expressed our love for on the podcast, but 0:01:53.520 --> 0:01:56.160 have never taken the time to explore in more depth, 0:01:56.520 --> 0:02:02.840 and that is coprolites aka fossilized feces. In our episode 0:02:02.880 --> 0:02:06.480 last week, we talked tapeworms, mostly about the tapeworms that 0:02:06.520 --> 0:02:11.040 commonly infect humans, but those tapeworms only represent a teeny 0:02:11.160 --> 0:02:14.960 tiny part of the puzzle of these parasites. As we mentioned, 0:02:15.080 --> 0:02:19.519 tapeworms are an incredibly ancient and highly diverse group of parasites, 0:02:19.919 --> 0:02:24.200 infecting thousands of animal species all over the globe. We're 0:02:24.280 --> 0:02:28.440 learning more about these amazing creatures all the time, from 0:02:28.480 --> 0:02:32.000 the discovery of new species expanding what we know about 0:02:32.000 --> 0:02:36.600 present day tapeworm ecology, to the identification of tapeworm bits 0:02:36.600 --> 0:02:39.520 in fossils, filling in some of the gaps in our 0:02:39.600 --> 0:02:43.200 knowledge of how these parasites and their hosts have evolved. 0:02:43.840 --> 0:02:46.919 And it's the second part, the fossil part, that I 0:02:47.000 --> 0:02:50.240 really want to focus on for this bonus episode. If 0:02:50.280 --> 0:02:53.079 you listen to our tapeworm episode last week, you may 0:02:53.120 --> 0:02:56.520 remember me mentioning a study from twenty thirteen that found 0:02:56.600 --> 0:03:00.880 tapeworm eggs in fossilized shark feces from two hundred seventy 0:03:01.200 --> 0:03:06.080 million years ago, which is so incredible, not only for 0:03:06.160 --> 0:03:09.040 the simple fact that we can look at and examine 0:03:09.120 --> 0:03:12.560 Pooh from millions of years ago, but also because this 0:03:12.680 --> 0:03:16.400 finding completely revised what we know about the timeline of 0:03:16.480 --> 0:03:21.320 cestode evolution and the history of intestinal parasites. And that's 0:03:21.360 --> 0:03:24.880 typically how coprolites come up on the podcast when we 0:03:24.960 --> 0:03:29.240 trace back how far a human parasite relationship extends, or 0:03:29.400 --> 0:03:34.040 examine how historical distributions of parasites differ from those of today. 0:03:34.680 --> 0:03:38.040 But coprolites are much much more than a tool for 0:03:38.160 --> 0:03:43.920 understanding parasite evolution or host parasite relationships. These magic packages, 0:03:44.160 --> 0:03:46.920 as my guest for this episode has called them, can 0:03:47.000 --> 0:03:50.960 yield incredible amounts of information on the typical diet of 0:03:51.000 --> 0:03:55.920 an extinct animal, the ecological relationships among species, and the 0:03:56.040 --> 0:04:00.440 environmental conditions near the time of fossilization, among other things. 0:04:01.200 --> 0:04:04.280 Although people have been studying copra lights since the first 0:04:04.320 --> 0:04:08.040 decades of the eighteen hundreds, some of the most impactful 0:04:08.080 --> 0:04:10.840 discoveries in this field have been made in just the 0:04:10.880 --> 0:04:14.200 past few decades by doctor Karen Chin, who is one 0:04:14.240 --> 0:04:18.400 of the world's leading experts and copralites. Doctor Chin has 0:04:18.520 --> 0:04:21.640 so graciously agreed to let me ask her all kinds 0:04:21.640 --> 0:04:25.520 of questions about fossilized specs today, and I am incredibly 0:04:25.600 --> 0:04:28.719 excited to dive in. So let's just take a quick 0:04:28.760 --> 0:04:54.240 break here and get to it. 0:04:54.320 --> 0:04:58.160 My name is Karen Chin, and I am a professor 0:04:58.240 --> 0:05:02.839 at the University of Colorado and I'm also curator of 0:05:02.880 --> 0:05:08.120 Paleontology at the cu Or University of Colorado's Museum of 0:05:08.200 --> 0:05:14.080 Natural History. I study ancient ecosystems, and mostly I focus 0:05:14.279 --> 0:05:18.320 on Mesozoic ecosystems, which is the time when the big 0:05:18.440 --> 0:05:21.159 dinosaurs were roaming around. 0:05:22.320 --> 0:05:25.880 Awesome, Thank you so very much for joining me today. 0:05:26.080 --> 0:05:31.320 I have been absolutely fascinated by copralites ever since learning 0:05:31.320 --> 0:05:34.880 about them during my masters and reading about hookworm eggs 0:05:34.920 --> 0:05:37.320 and the peopling of the Americas and all the things 0:05:37.360 --> 0:05:41.919 we can learn from fossilized poop. And I've always wanted 0:05:41.920 --> 0:05:44.679 to dig in a little bit deeper and explore more, 0:05:44.839 --> 0:05:49.000 especially of the non parasite side of things. So I 0:05:49.040 --> 0:05:51.560 am really thrilled for this interview. 0:05:52.240 --> 0:05:54.159 Well, thank you, thank you for inviting me. 0:05:54.800 --> 0:05:58.360 Of course, So could you start us off by defining 0:05:58.400 --> 0:06:00.880 the word copralite, Yes. 0:06:00.720 --> 0:06:08.960 I can. A copralite is fossilized feces. Sometimes people immediately 0:06:09.000 --> 0:06:11.480 think it has to be from a dinosaur, but it 0:06:11.480 --> 0:06:15.760 could be from a fish, or a human or an insect. 0:06:16.279 --> 0:06:22.640 It just means fossilized feces. And there's oh, there's a 0:06:22.680 --> 0:06:28.960 whole variety of them. But I would say that since 0:06:29.000 --> 0:06:33.599 I work on very old fossils over say most of 0:06:33.640 --> 0:06:36.640 them fossils I work on are over sixty six million 0:06:36.720 --> 0:06:42.920 years old. What copralites can be preserved in very what 0:06:43.000 --> 0:06:46.159 I would call young sediments only a few hundred years 0:06:46.240 --> 0:06:50.000 or a few thousand or a million years old, And 0:06:50.240 --> 0:06:54.120 how they are preserved often depends on their age. So 0:06:54.200 --> 0:06:58.200 what the kind of copralites I work on? Are hard? 0:06:58.440 --> 0:07:03.760 They're mineralized, Whereas if you talk to an archaeologist, many 0:07:03.800 --> 0:07:07.600 of the copralites they work on are still they were 0:07:07.640 --> 0:07:13.800 preserved through drying, through desiccation, and if archaeologists rehydrate them, 0:07:13.840 --> 0:07:17.200 they can still have odors. Where most of the material 0:07:17.480 --> 0:07:19.800 WEAK work on is mineralized. 0:07:20.960 --> 0:07:23.080 What do coprolites look like? 0:07:23.120 --> 0:07:25.520 I'm sure there's not a one size fits all answer 0:07:25.760 --> 0:07:28.520 to this question. And so how variable can they be 0:07:28.840 --> 0:07:30.800 in their shape and size? 0:07:31.960 --> 0:07:37.200 They that's a great question. They're highly variable, and their 0:07:37.400 --> 0:07:43.200 variableness often depends on how big they are. So if 0:07:43.240 --> 0:07:49.400 you're talking about little feces from insects or shrimp, they 0:07:49.520 --> 0:07:55.800 often have a very predictable size and shape. But if 0:07:55.800 --> 0:08:01.160 you're talking about feces from say a duckbill dinosaur, often 0:08:01.240 --> 0:08:04.160 they just do not hold their shape, either when they're 0:08:04.200 --> 0:08:08.720 deposited or when they're trampled. And you can see that 0:08:08.880 --> 0:08:11.280 yourself if you go to the zoo and look at 0:08:11.280 --> 0:08:15.240 the elephant dung. One or two of them might be 0:08:15.440 --> 0:08:19.160 have a nice round shape, but many of them are 0:08:19.200 --> 0:08:25.120 just kind of trampled and have no recognizable shape. So 0:08:26.320 --> 0:08:30.320 the shape is usually dependent on the size of the animal, 0:08:31.640 --> 0:08:35.560 and then within that, when feces are first produced, they 0:08:35.600 --> 0:08:40.520 can be oh little teeny pellets, They can be ovoid, 0:08:40.800 --> 0:08:44.960 they can be more like a cowpie, they can be 0:08:45.080 --> 0:08:49.280 really irregular, and this depends again upon the size and 0:08:49.400 --> 0:08:52.600 also upon the diet and the kind of animal that 0:08:52.679 --> 0:08:53.360 produced it. 0:08:54.360 --> 0:08:57.840 Copulates are a type of trace fossil, right, So what 0:08:57.920 --> 0:09:01.040 are some other examples of trace fos foscils and how 0:09:01.160 --> 0:09:03.800 does the information that we can get from these type 0:09:03.800 --> 0:09:07.720 of fossils differ from the info we can glean from 0:09:07.880 --> 0:09:09.960 something like a body fossil for. 0:09:09.840 --> 0:09:15.559 Instance, Yes, that's a great distinction. Body fossils are part 0:09:15.600 --> 0:09:18.880 of what the animal look like or a plant. I 0:09:18.920 --> 0:09:23.480 shouldn't limit it to animals. Of petrified wood is a 0:09:23.559 --> 0:09:27.240 kind of body fossil, because that's part of what constituted 0:09:27.559 --> 0:09:33.040 the structure of the animal. In contrast, trace fossils record 0:09:33.240 --> 0:09:38.559 behavior of different organisms. So tooth marks in say bone, 0:09:39.320 --> 0:09:44.400 or brows in the sediment, or footprints or corpralites, they 0:09:44.480 --> 0:09:49.920 all record some kind of behavior and they tell us 0:09:50.000 --> 0:09:54.680 They provide different perspectives because with body fossils we can 0:09:55.240 --> 0:09:59.640 try to envision what an animal or plant or whatever 0:09:59.720 --> 0:10:02.640 look like, some kind of organism, what they looked like. 0:10:03.520 --> 0:10:07.520 But with trace fossils we can see, oh they burrowed here, 0:10:07.679 --> 0:10:10.920 they burrowed in this manner, what were they doing? What 0:10:11.040 --> 0:10:14.679 did they eat? How did they walk? How fast did 0:10:14.679 --> 0:10:17.839 they run? There's they're different kinds of questions, but they 0:10:17.960 --> 0:10:22.480 enrich our understanding of ancient life. 0:10:22.640 --> 0:10:28.680 Of course, everyone and everything poops, generally speaking, but you 0:10:28.720 --> 0:10:32.320 know what's in that poop can change substantially from day 0:10:32.360 --> 0:10:35.160 to day, and so if a trace fossil like a 0:10:35.160 --> 0:10:38.680 copralite is capturing like a snapshot of an image, a 0:10:38.720 --> 0:10:42.480 snapshot of what that animal ate and that particular day 0:10:42.800 --> 0:10:45.720 and what happened to just be preserved, And so how 0:10:45.760 --> 0:10:49.920 does that affect our interpretation of what we see inside 0:10:49.960 --> 0:10:50.800 that copra late? 0:10:51.840 --> 0:10:56.680 Well, I like that you use the phrase snapshot. We 0:10:57.840 --> 0:11:00.760 like to use that too, because it's just kind of 0:11:00.800 --> 0:11:04.360 a single frame in the whole movie of ancient life, 0:11:04.960 --> 0:11:09.280 and sometimes it can be representative of the past, and 0:11:09.320 --> 0:11:13.800 sometimes maybe it was an aberrant situation. Maybe it would 0:11:13.840 --> 0:11:17.360 be like if you looked at my diet on a 0:11:17.440 --> 0:11:19.680 day that all I wanted to eat was ice cream, 0:11:19.960 --> 0:11:24.720 that might not be relevant for my normal diet. 0:11:25.400 --> 0:11:28.760 So you mentioned, of course that the size of the 0:11:28.800 --> 0:11:32.319 animal and the type of the animal can really affect 0:11:32.640 --> 0:11:35.880 what the copralite looks like simply because of what's in 0:11:35.920 --> 0:11:36.679 the poop. 0:11:36.760 --> 0:11:37.400 And so on. 0:11:38.040 --> 0:11:41.960 But how does that affect how copraltes form? Well, I 0:11:41.960 --> 0:11:44.440 guess my first question is how do they form? And 0:11:44.480 --> 0:11:47.800 then the second sort of add on question is how 0:11:47.800 --> 0:11:52.120 do things like animal diet or the environmental conditions, how 0:11:52.120 --> 0:11:54.520 do those things play a role in whether or not 0:11:54.640 --> 0:11:56.439 that poop becomes fossilized. 0:11:57.720 --> 0:12:03.559 Yes, all those factors are super important. If we go 0:12:03.679 --> 0:12:09.160 back to thinking about archaeological samples that are only maybe 0:12:09.240 --> 0:12:14.600 hundreds or thousands of years old. Those can preserve in 0:12:14.679 --> 0:12:19.319 a very dry environment, say in a cave. But if 0:12:19.360 --> 0:12:25.280 you're talking about older material, the most common method of 0:12:25.600 --> 0:12:29.280 feces being preserved, and it sounds crazy that we could 0:12:29.320 --> 0:12:35.839 actually preserve soft material like feces, but if it becomes mineralized, 0:12:36.440 --> 0:12:41.840 it can preserve it in three dimensions. So the duet 0:12:42.400 --> 0:12:46.840 actually plays a major role in whether ancient feces were 0:12:46.880 --> 0:12:52.320 mineralized or not. Because if you're a carnivore, if you 0:12:52.440 --> 0:12:56.760 feed on vertebrates that have bones or something that has 0:12:56.920 --> 0:13:01.760 only soft tissue, either way that they're is phosphorus in bone. 0:13:01.800 --> 0:13:06.920 There's phosphorus in soft tissue, and that can contribute to 0:13:06.960 --> 0:13:11.280 the mineral called calcium phosphate, and there's a lot of 0:13:11.320 --> 0:13:13.800 calcium around, so that's a little easier to come by, 0:13:13.880 --> 0:13:17.000 but phosphorus is not so easy to come by. So 0:13:17.040 --> 0:13:19.920 if you are a carnivore and have a diet that 0:13:20.000 --> 0:13:24.000 has phosphorus in it, your feces are more likely to 0:13:24.080 --> 0:13:28.320 be preserved if they are deposited in under the right conditions. 0:13:29.440 --> 0:13:33.240 So that means that most of the feces throughout the 0:13:33.280 --> 0:13:38.280 world in museums are mostly from carnivores, which is kind 0:13:38.320 --> 0:13:43.679 of counterintuitive because they're far more herbivores than there are carnivores. 0:13:44.200 --> 0:13:50.400 But herbivore coprolites require an external source of elements that 0:13:50.520 --> 0:13:56.520 can help them be mineralized, so actually herbivore coprolites are 0:13:56.960 --> 0:13:58.600 very very rare. 0:13:59.720 --> 0:14:03.720 And in terms of the environmental conditions at the time, 0:14:04.320 --> 0:14:08.480 or maybe environmental conditions nowadays, are there hot spots that 0:14:08.520 --> 0:14:11.480 we see around the world where there happens to be 0:14:11.520 --> 0:14:13.960 a lot of copralite deposits. 0:14:15.240 --> 0:14:21.320 Yes, indeed, the hot spot would actually be the likelihood 0:14:21.520 --> 0:14:25.800 of whether something is buried or not. And this also 0:14:25.960 --> 0:14:30.760 works in terms of preserving body fossils. Most fossils can 0:14:30.960 --> 0:14:35.560 be more easily preserved if they are rapidly buried, and 0:14:35.600 --> 0:14:40.240 that goes for feces as well, because what happens is 0:14:40.400 --> 0:14:44.280 if the feces are left exposed on the surface, they 0:14:44.360 --> 0:14:49.280 can be subjected to rain, so in any erosion, or 0:14:50.000 --> 0:14:52.760 animals that step on it or feed on it, or 0:14:53.360 --> 0:14:56.400 other things that just decay it, it can be decayed 0:14:56.400 --> 0:15:01.320 by bacteria. If you bury the feces, you can slow 0:15:01.520 --> 0:15:07.120 bacterial decomposition, and if the conditions are right, and we're 0:15:07.160 --> 0:15:13.240 still trying to understand what those conditions are, bacteria can 0:15:13.360 --> 0:15:18.600 actually facilitate mineralization of the soft material. And again this 0:15:18.680 --> 0:15:23.360 seems ironic because bacteria. You usually think of bacteria as 0:15:23.400 --> 0:15:29.280 decaying things, but as bacteria live, they can produce some 0:15:29.520 --> 0:15:36.080 substances or change the micro environment that actually facilitates mineralization. 0:15:36.400 --> 0:15:40.720 And many experiments have been done investigating the role of 0:15:40.800 --> 0:15:47.520 bacteria in mineralization. And it may be that many, maybe 0:15:47.600 --> 0:15:53.920 even most processes of mineralization in place, and I'm talking 0:15:53.920 --> 0:15:58.440 about in sedimentary environment. I'm not talking about volcanics or 0:15:58.560 --> 0:16:04.680 magmas or anything, but just producing chemical minerals in place 0:16:05.520 --> 0:16:12.440 seem to be facilitated by the activity of microbes, especially bacteria. 0:16:13.200 --> 0:16:17.640 And are those bacteria are they environmental bacteria or like 0:16:17.680 --> 0:16:21.440 in the soil, or are they internal bacteria as part 0:16:21.440 --> 0:16:25.000 of like the gut microbiome and shed along with the feces. 0:16:26.200 --> 0:16:29.440 We are still trying to figure out which bacteria can 0:16:29.560 --> 0:16:35.040 do this. The thing about feces is that feces have 0:16:35.400 --> 0:16:40.440 so much so many bacteria in them, but there's lots 0:16:40.440 --> 0:16:45.360 so they can be readily preserved if the conditions are right. 0:16:46.440 --> 0:16:51.120 Which bacteria That's an excellent question. A student that I 0:16:51.160 --> 0:16:55.440 worked with, doctor Joseph Daniel. He once did an experiment 0:16:55.560 --> 0:17:00.760 with me where he buried chunks of bone and then 0:17:01.080 --> 0:17:05.920 dripped a super saturated solution of calcium carbonate over the bone. 0:17:05.960 --> 0:17:09.560 But some of the pieces of bone had been treated 0:17:09.640 --> 0:17:13.640 to reduce the numbers of bacteria. It's hard to get 0:17:13.720 --> 0:17:16.640 rid of everything, but he reduced a lot of them. 0:17:17.240 --> 0:17:23.520 In the chunks of bone where the bacterial populations were reduced, 0:17:24.359 --> 0:17:28.320 there was very little precipitation of the calcium carbonate that 0:17:29.119 --> 0:17:33.080 was percolating through the sand and around the bones. 0:17:34.280 --> 0:17:37.720 Speaking of bacteria, most of the time when we've brought 0:17:37.800 --> 0:17:40.840 up coprolites on the podcast before, it's been in the 0:17:40.880 --> 0:17:45.800 context of parasite eggs, specifically human parasite eggs that have 0:17:45.920 --> 0:17:48.720 been found in certain specimens where and when What does 0:17:48.760 --> 0:17:51.960 that tell us about human evolution or parasite evolution. But 0:17:52.119 --> 0:17:55.360 coprolites can tell us a great deal more about the 0:17:55.400 --> 0:17:59.080 animal that produced that poo than just what parasites they 0:17:59.080 --> 0:18:01.480 may have been infected with. So what are some of 0:18:01.520 --> 0:18:05.399 the other things that we can learn from copralates. 0:18:05.520 --> 0:18:09.760 Yes, we can learn several different things, and it usually 0:18:09.800 --> 0:18:14.760 depends on the kind of preservation of the copralate that 0:18:14.840 --> 0:18:19.920 you're examining. I think the most common source of information 0:18:20.000 --> 0:18:24.160 we look for is what was the animal eating? And 0:18:24.359 --> 0:18:29.280 sometimes we can recognize some very distinctive bits and pieces. 0:18:29.320 --> 0:18:33.639 And you have to kind of think three dimensionally because 0:18:33.760 --> 0:18:37.560 quite often when you're looking at dietary residues in a 0:18:37.600 --> 0:18:44.360 copra light, they've been chomped, they've been digested with gastric juices, 0:18:45.080 --> 0:18:50.760 and then they've probably been changed through geological processes, through 0:18:50.800 --> 0:18:56.040 mineralization or by bacterial decay. So we look for bits 0:18:56.080 --> 0:18:59.360 and pieces that can give us a glimpse into who 0:18:59.400 --> 0:19:03.200 were the victim who was eaten. Sometimes we see pieces 0:19:03.280 --> 0:19:06.680 of bone, sometimes we see pieces of shell, sometimes we 0:19:06.720 --> 0:19:11.360 see lots of leaves, and sometimes those things are very 0:19:11.520 --> 0:19:16.480 very difficult to recognize, but we're getting better and sometimes 0:19:16.520 --> 0:19:19.040 we can see just a little piece of something and say, well, 0:19:19.080 --> 0:19:23.160 that's a piece of bone. In most cases, we assume 0:19:23.800 --> 0:19:26.679 that when we find something in a copral like it 0:19:26.800 --> 0:19:30.879 was eaten, it was food. But sometimes we can also 0:19:31.000 --> 0:19:36.000 see evidence of organisms that were visitors that visited a 0:19:36.080 --> 0:19:41.800 dung pile after it was deposited, and actually one study 0:19:41.800 --> 0:19:46.000 that I worked on with colleagues, we found over one 0:19:46.080 --> 0:19:49.840 hundred and forty I don't know more than that snails 0:19:49.880 --> 0:19:54.080 associated with copra likes. They were preserved in them, on 0:19:54.200 --> 0:19:58.560 top of them, and we examined how complete they were 0:19:58.600 --> 0:20:02.600 and actually found them more Most of them were fairly complete. 0:20:02.800 --> 0:20:09.240 So this suggested that these snails were post depositional visitors 0:20:09.960 --> 0:20:16.440 because snails actually often feed on dung, snails and slugs 0:20:16.720 --> 0:20:20.360 because they like the bacteria in dung, and sometimes when 0:20:20.400 --> 0:20:23.640 people are studying snails, they will put it dung out 0:20:23.680 --> 0:20:28.680 for bait to attract them. So that indicated that in 0:20:28.680 --> 0:20:31.800 this case, even though we found snails in the cobra light, 0:20:32.000 --> 0:20:35.919 they were not necessarily eaten. It's possible that some of 0:20:35.960 --> 0:20:38.680 them were eaten, but it appears that most of them 0:20:39.200 --> 0:20:43.320 visited the dung after it was deposited. So this provides 0:20:43.359 --> 0:20:48.600 another angle of interpreting the ancient environment because this shows 0:20:48.720 --> 0:20:53.880 how waste materials like dung were recycled in ancient environments. 0:20:54.600 --> 0:20:58.800 So we have diet, we have recycling. We can also 0:20:58.960 --> 0:21:04.080 just tell you if something is eaten, it's a contemporary 0:21:04.359 --> 0:21:07.720 of the dinosaurs, so we can learn who was living 0:21:07.760 --> 0:21:13.240 with the dinosaurs, whether or not they were eaten. And finally, well, 0:21:13.280 --> 0:21:16.000 I shouldn't say finally. We're still finding more and more 0:21:16.280 --> 0:21:19.760 about what copraltes can tell us. But i'd say of 0:21:19.920 --> 0:21:24.920 the fourth major category is when we study some copraltes, 0:21:25.000 --> 0:21:30.359 we can learn how it was preserved. And a good 0:21:30.400 --> 0:21:33.800 example of this, the best example that I have worked 0:21:33.800 --> 0:21:40.000 on is when we studied a tronosaur copralite, not t Rex, 0:21:40.080 --> 0:21:45.200 but a smaller, slightly smaller, and older relative, probably ten 0:21:45.280 --> 0:21:49.760 million years older than t Rex, and when we examined 0:21:49.800 --> 0:21:54.320 the copra light we found a mineralized muscle tissue. 0:21:54.440 --> 0:21:55.240 This was just. 0:21:56.920 --> 0:22:00.919 Was so shocking because you'd expect, wait a minute, this 0:22:01.080 --> 0:22:03.560 can't be this went through the dinosaur's gut, and then 0:22:03.600 --> 0:22:06.439 it came out, and you'd think that somewhere along the 0:22:06.480 --> 0:22:10.560 way it was the muscle tissue was either digested or 0:22:10.640 --> 0:22:17.520 else decomposed by bacteria. But what this told us was 0:22:17.600 --> 0:22:22.919 that the gut residence time of the food was rather quick. 0:22:22.960 --> 0:22:26.520 If the food had just sat in the dinosaur's gut 0:22:26.560 --> 0:22:29.120 for a long period of time, it would have been 0:22:29.560 --> 0:22:34.880 more completely broken down. But if it went through relatively quickly, 0:22:35.359 --> 0:22:41.520 you wouldn't necessarily have digestive juices actually attacking every little 0:22:41.960 --> 0:22:45.840 bit of what was eaten. And when I was working 0:22:45.880 --> 0:22:49.439 on this, I found an article that explained that muscle 0:22:49.520 --> 0:22:53.959 tissue has been found in the feces of dogs that 0:22:54.000 --> 0:22:57.399 were fed raw meat. And you figure, if a dog 0:22:57.560 --> 0:23:01.200 has a skull, that's maybe a big dog maybe has 0:23:01.240 --> 0:23:07.440 a canner eleven inch long skull, But a tronosaur could 0:23:07.520 --> 0:23:10.960 have a skull was three feet long, and they could 0:23:11.040 --> 0:23:14.280 not chew like a dog could. They could gulp and swallow, 0:23:14.960 --> 0:23:19.280 So if there was a relatively fast gut residence time, 0:23:20.080 --> 0:23:24.000 all of those bits of food would not necessarily be digested. 0:23:25.200 --> 0:23:28.879 And then once it was deposited, we have to mineralize 0:23:28.920 --> 0:23:33.680 it very quickly before all the bacteria decompose the muscle tissue. 0:23:33.680 --> 0:23:40.080 But again, as we've learned, bacteria can facilitate mineralization, and 0:23:40.920 --> 0:23:45.280 there have been scientists who have taken dead animals like 0:23:45.359 --> 0:23:49.800 dead shrimp and buried them and they have documented mineralization 0:23:50.040 --> 0:23:55.000 of the muscle tissue within weeks. So all of these 0:23:55.080 --> 0:23:59.320 things tell us about a little bit about the digestive track. 0:23:59.440 --> 0:24:03.359 They tell us about the process of mineralization, and that 0:24:03.520 --> 0:24:07.639 was not originally why I wanted to study this Toronto's 0:24:07.720 --> 0:24:09.960 ark for LTE. I wanted to learn about the diet, 0:24:10.000 --> 0:24:14.400 but it provided such an interesting window on other kinds 0:24:13.720 --> 0:24:17.119 of aspects of the fossil record. 0:24:18.080 --> 0:24:21.199 That must have been so thrilling to see that a 0:24:21.280 --> 0:24:25.520 muscle tissue. What an unexpected finding it was. 0:24:26.000 --> 0:24:29.840 It was such a fun study, but it was it 0:24:29.880 --> 0:24:32.639 was challenging because when I first saw it, I thought 0:24:33.000 --> 0:24:38.040 that that doesn't look like plant tissue. Maybe it's muscle tissue. No, 0:24:38.200 --> 0:24:40.439 it can't be. It can't it just can't be. And 0:24:40.520 --> 0:24:44.240 I'd go to bed at night thinking it's not muscle tissue. 0:24:44.280 --> 0:24:46.800 Then I'd wake up in the morning, maybe it could be. 0:24:47.080 --> 0:24:49.880 Then the next day I'd think, no, it's plant tissue, 0:24:50.200 --> 0:24:52.320 and I'd wake up in the morning, No, it could 0:24:52.359 --> 0:24:56.760 be muscle tissue. And so, because I'm not a specialist 0:24:57.000 --> 0:25:03.280 in anatomical tissues, I sought out a colleague at Stanford 0:25:03.880 --> 0:25:09.440 who actually worked on muscle tissues and shared it with him, 0:25:09.600 --> 0:25:14.600 and doctor Rando said, yes, I think this seems to 0:25:14.640 --> 0:25:19.520 be the most likely explanation. So it was. It was 0:25:19.640 --> 0:25:24.600 so surprising, but interestingly as I was making looking at 0:25:24.600 --> 0:25:29.600 the microscope through thin sections of this specimen, I suspected 0:25:29.640 --> 0:25:32.879 that it was muscle tissue. But then one day I 0:25:33.080 --> 0:25:37.760 happened to make some random fin section and could actually 0:25:37.840 --> 0:25:43.199 see the mio fibular striations in skeletal muscle tissue. But 0:25:43.280 --> 0:25:47.400 that was so serendipitous to get just the right angle 0:25:47.440 --> 0:25:53.200 and the right view, and that really helped seal our interpretation. 0:25:54.680 --> 0:25:56.920 And so is that is that one of the major 0:25:56.960 --> 0:25:59.920 ways that you study coprolites is through, you know, take 0:26:00.000 --> 0:26:04.960 making this fossil and cutting tiny little slivers, little sections. 0:26:04.560 --> 0:26:05.840 And putting them on a microscope. 0:26:06.200 --> 0:26:08.199 What are some of the other ways, or if you 0:26:08.200 --> 0:26:10.479 could talk a little bit more about these methods that 0:26:10.520 --> 0:26:12.600 you use to study these culporal lights. 0:26:13.760 --> 0:26:18.679 Yes, I really like making those thin sections, like you explained, 0:26:19.400 --> 0:26:23.040 but it is a destructive process, and before you ever 0:26:23.160 --> 0:26:26.439 do anything like that, you have to first of all 0:26:27.080 --> 0:26:33.040 ask a museum for permission to destructively analyze some of 0:26:33.320 --> 0:26:37.160 a sample. And you often don't necessarily want to do 0:26:37.240 --> 0:26:40.439 too much of this, especially if it's a very unique specimen. 0:26:41.600 --> 0:26:45.920 So that is one way we do microscopy on broken pieces. 0:26:46.440 --> 0:26:51.119 But one thing we are investigating now is looking using 0:26:51.560 --> 0:26:57.080 computed tomography or CT to examine what's inside, and I 0:26:57.520 --> 0:27:03.000 and my students have used X ray computed tomography and 0:27:03.720 --> 0:27:08.800 neutron computed tomography. And one of my colleagues in Europe, 0:27:09.280 --> 0:27:15.840 doctor Martin Farnstrom, has done exceptional work in using synchrotron 0:27:16.000 --> 0:27:21.720 radiation and then he's been able to find really cool 0:27:22.440 --> 0:27:25.600 beetle parts in some of the COPRA lights and other 0:27:25.720 --> 0:27:28.880 things in some of the material he studied, and that 0:27:29.040 --> 0:27:33.399 is really great because it's non destructive. But there's pros 0:27:33.440 --> 0:27:37.080 and cons to both methods. I think sometimes you can 0:27:37.160 --> 0:27:39.920 see more in the thin section, but you're only looking 0:27:39.960 --> 0:27:46.160 at a two dimensional slice and it's destructive. With computed tomography, 0:27:46.200 --> 0:27:50.440 you're seeing three dimensions, but you may not necessarily see 0:27:50.520 --> 0:27:55.639 cellular detail that might be preserved. So well, we're throwing 0:27:55.840 --> 0:28:00.680 is many different techniques at these COPRA lights to learn 0:28:00.760 --> 0:28:04.080 as much as we can. And what we are learning 0:28:04.119 --> 0:28:07.000 these days, I imagine in twenty years people will be 0:28:07.000 --> 0:28:10.480 able to deduce so much more information. 0:28:11.880 --> 0:28:13.600 One of the things that crossed my mind was that 0:28:13.640 --> 0:28:16.960 you're able to tell so much from this copralight, but 0:28:17.080 --> 0:28:21.000 how can you use that information to help you determine 0:28:21.000 --> 0:28:23.760 what animal it might have come from. Is it just 0:28:23.800 --> 0:28:25.960 from the copra light itself or is it also from 0:28:26.080 --> 0:28:28.920 what else you find in the area. 0:28:29.200 --> 0:28:32.960 Yes, this is another time when we use multiple lines 0:28:33.080 --> 0:28:37.119 of evidence. The most important line of evidence is what 0:28:37.320 --> 0:28:41.719 is the age of the sediments. So if I'm looking 0:28:41.920 --> 0:28:47.640 at Cretaceous age sediments, I know that only a certain 0:28:47.720 --> 0:28:50.760 number of animals could have produced it. I won't say 0:28:50.840 --> 0:28:54.120 that was it could have been produced by a wooly 0:28:54.200 --> 0:28:57.840 mammo because they didn't live in the Cretaceous. And then 0:28:57.920 --> 0:29:01.240 you can you can fine tune so that when you 0:29:01.360 --> 0:29:05.120 find a coprali, you're looking at maybe just what are 0:29:05.160 --> 0:29:09.720 the contemporaneous organisms that we find in the sediments of 0:29:09.760 --> 0:29:13.120 the same age. So that is one line of evidence. 0:29:13.200 --> 0:29:17.080 Another line of evidence is the size. If you find 0:29:17.120 --> 0:29:21.160 a really large fecal deposits, you know it wasn't produced 0:29:21.200 --> 0:29:25.840 by a small rodent size mammal. If you find a 0:29:26.000 --> 0:29:30.080 small piece, that's a little more difficult because small pieces 0:29:30.520 --> 0:29:33.440