Video
Dig Up! The Latest Research at Agate: 2024: Sunshyne Santos
Transcript
Audio Description –#1
Title on a plain background reads, "How North American Rhinos Developed" by Sunshyne Santos, California State Polytechnic University, Pomona. Sunshyne is a female with light skin complexion, glasses, and long black hair. Then, a young girl with long dark hair, parted down the middle, sits on a horizontal metal guardrail that sticks out from an indoor exhibit. Sunshyne reads from three bullet points on the screen.
Slide #1 & #2
Hello. My name is in Sunshyne Santos. I am a grad student at California State Polytechnic University, Pomona and today I'd like to discuss how North American Rhinoceros developed. So, um I would like to go into a little bit of background about myself. I was born into a Latino family with an unconventional upbringing. um Essentially what that means is basically that um my parents were both gang-related, um my mom's family included as well. It was actually through her brother, my uncle, in which I did learn about college. uh He would send me um basically information about colleges and universities and scholarships. And he essentially was um making a connection while also trying to show me that I had options; um that this was not the only route I had to take. um And so, I was a first-generation college student, which came with its own set of challenges. And um some of those challenges being that I didn't really have anyone to turn to when it came to um asking questions about applications or um filing for financial aid or any college related issues actually. um And so it was very much a thing that I had to learn on my own. And on top of all of that, I also started to lose my vision at the age of five when I was diagnosed with an eye disease. And um it wasn't until I turned 15 that I ended up losing my vision in that eye almost completely, um or at least to the point where I can no longer use it. So, I've never had the um opportunity to learn how to drive or any of that. I've always had to rely on public transportation, which it has its own challenges in Los Angeles unfortunately. um It's not very reliable, so I've had to figure out how to work around that.
Audio Description #2
Two vertical pictures fill the screen. Left, Sunshyne wears blue jean overalls and a scarf tied over her head, a rock hammer attaches to a backpack strap, and notebooks rest on her lap as she sits on dark textured rocks piled up on a ridgetop. Right, Sunshyne holds a caliper next to a black cylindrical bone. Several small trays of these bones rest at the desk near her.
Slide #3
So pictured here is me in my undergrad. um When I started college, I was not sure what I wanted to do. I was caught between geology and biology, and it wasn't until I took a course with um Dr. Prothero, that I learned that paleontology was actually an option for me. And so, um I did take a few more paleo related courses with him and eventually talked with him about uh the possibility of doing research. I was then given the opportunity to do research at La Brea Tar Pits. And that was really special to me because um growing up, although my parents didn't understand college, um my dad did try to be supportive by taking me to museums. And um the La Brea Tar Pits was actually the first museum we did go to. So, it felt fitting that that was also the first museum I did research at.
Audio Description #3
Two other women and Sunshyne stand indoors next to a man in a suit and tie.
Slide #4
Beyond this it felt really special to be included in a group of other women who were also trying to take the same route as me. um Everyone has been incredibly supportive and continues to do so. And it felt extra special um to go through kind of a similar instances with other people who um who are just going through the same fight as me essentially.
Audio Description #4
Title, "Some Rhino History." Two dark brown rhinos look at us in a grassland. One has one pointed horn above its nose and is less than half the size of the other who has two pointed horns in a vertical line. Then, the geologic graph with illustrations of a variety of rhinos within the Eocene, Oligocene, and Miocene epochs listed vertically. The Menoceras is listed within the third group labelled Rhinocerotidae within the early Miocene.
Slide #5 & #6
So, I did want to go over some rhinoceros history with you all. So rhinoceros um are actually extremely widespread um amongst the northern continents and have been for the last 40 million years. But today, I specifically want to talk about Monoceras.
Audio Description #5
Seven sketches of heads from different rhino species. Two of the seven show horns. Text: horns are made of glued hair, no bony core, and rarely fossilized. Then, two whitish skulls fill the screen. Both have upper and lower jaws with teeth, a large frontal open space revealing a hollow cavity, and a structure that protrudes from the rest of the head and hangs over the teeth. The structure on the left is smooth, while the one on the right is textured.
Slide #7 & #8
And I did include this picture because I know that although we all may think of rhinoceros as being horned um mammals, they actually mostly did not have horns. And we know this because um although horns don't really fossilize well in the fossil record, they do um have a specific texture on the skull where they were um fused to the skull. And so that's kind of pictured here. um We have two skulls both of which are from the um offsite warehouse of collections from the Natural History Museum of LA. Both of them are white rhinoceros. The left being female; the right being male. You can see that the female has a relatively um consistent texture amongst the whole skull including on the nasal ridge. However, the male has almost like a spongy looking texture. um It's really coarse and rough and looks very different from the rest of the skull.
Audio Description #6
Title, "Family Rhinocerotidae." A sketch of a rhino skull which is a rounded rectangular shape with a bone that sticks out diagonally from the back and a curved bone that hangs over a frontal gap. In the front, arrows point to where a strip of bones touch vertically several inches in front of the teeth. Then, three photos appear on screen. First, four-legged skeleton is propped up on vertical poles indoors. Second, actual brownish red skull of a rhino. Third, one rhino jaw turned upside down reveals six to seven singular teeth in a row on each side.
Slide #9
And so, from here I'd like to talk about um Subhyracodon; the name being a little misleading um because it's not a Hyracodon but it did have priority due to when it was named. But it is a pretty widespread genus. um There are hundreds of specimens in the Natural History Museum of New York, as well as the commercial market. And here is a skeleton picture here, as well as two pictures of skulls. If you look on to the right picture, you can tell that the molars actually have a shape resembling the symbol Pi and this is unique amongst rhinoceros.
Audio Description #7
Sunshyne reads from the screen. Then two pictures appear over the text. First, sketch of a Aceratherium tridactylum's skeleton from Bulletin AMNH. Second, illustration of two gray rhinos in a grassland. They have a narrow long tail, short legs, and a flat tubular body that extends into a thick neck and oblong head.
Slide #10
And so, um onward we talk about Aceratherium tridactylum which was later reclassified as Subhyracodon tridactylum. And this is the main Whitneyan species. uh It has the beginnings of a horn supporting bridges on the nasal bones um but eventually it was reclassified again by um Prothero in 2005 into Diceratherium. And here is an illustration um depicting it when it was known as Aceratherium. And um also another illustration depicting it, what it may have looked like alive.
Audio Description #8
Three actual skulls line up vertically on screen. The bone structure over where the teeth would be on the top skull is wide and curves up. The middle skull structure is wide and flat, while the bottom skull structure is narrow. Then, a picture appears over the slide of Sunshyne holding an actual rhino skull indoors in a narrow hallway between closed metal lockers.
Slide #11
And uh 31 million years ago, Subhyracodon evolved into Diceratherium in which this genus is known for their um developed nasal ridges. And so, we have three different species pictured on the right. The very bottom is the previously mentioned Diceritherium Tridactylum. And so, um the nasal ridges weren't very pronounced at all; they're barely beginning. Whereas the very top skull on Diceratherium armatum, the nasal ridges are very pronounced and wide and flaring even. um However last year, my research group and I named the intermediate species Diceratherium marriottae. um And basically you can see the start of the nasal ridges becoming a little bit more pronounced. And pictured here is me holding um the skull of D. marriottae.
Audio Description #9
Eight black and white images of upper or lower rhinos skull fragments labeled A through H with a ruler next to each skull has a nasal bone that sticks out in a different way; from short and stubby to flat and wide. Then, a short four-legged animal skeleton displayed upright on vertical stands. A small number three tag sticks to one of the stands. Text, first horns were in pairs at tip of snout.
Slide #12 & #13
So, we know that Diceratherium armatum um is where the really pronounced nasal ridges are. um However, before that pretty much all paired horn rhinoceros were called Diceritherium and this was misleading in a way. um This also included Diceritherium cooki which was later reassigned Menoceras arkarense in 1969. And pictured here is um a model of Monoceras arikarense, um which was originally from Eurasia. And it was actually the first rhinoceros uh of which the horn bases um were present in male skulls in North America. And this is actually the most common fossil at the Agate bone beds.
Audio Description #10
Two illustrations of rhinos with two pointed horns on either side of their nose. Left: gray rhino against white background. Its four legs start thick then taper down to wrinkled knees and three toes on its feet. Right: Brown rhino in a grassy environment with its long tail curled up to its rump.
Slide #14
And pictured here is uh two illustrations of the Monoceras arikarense. uh I just wanted to point out like that the legs look a little more long and thin compared to what we would think of with rhinos.
Audio Description #11
A circular pile of scattered bones surrounded by short dirt ridges. Five or six skulls appear among mostly cylindrical bones. A small sign in the pile reads, "Objects are fragile. Please do not touch."
Slide #15
And this picture um depicts the Agate bone bed. um If you look carefully, you can actually see Menoceras skulls in the pile.
Audio Description #12
Sunshyne uses a caliper to measure a line of teeth on a rhino skull indoors at a table. Four long shelves full of fossils exist behind her. Then, she reads a list of four bullet points on a slide titled, "Methods."
Slide #16
So, the goals of my project were to compare um the growth of young Monoceras arikarense from Agate and a different genus or species to Teleoceras proterum from Mixson's bone bed in Florida to the pattern of living rhinoceros um African rhinoceros. And so the methods that I used, um I measured as many unbroken juvenile limb bones as possible using metric tape. I focused on the diaphysis length as well as the shaft circumference of the limb bones. And I then used Excel and PAST to get a bi-varied, linear plot of the growth. And I compared this with um published data from African black rhinoceras.
Audio Description #13
Sunshyne reads a list of two bullet points on a slide titled "Isometric Growth." Then, a picture appears over the text four images of newts lined up from newly hatched to adult. Each has slimy, smooth, reddish-brown tubular bodies that are horizontal to the ground with no section breaks between the head and the tip of the tail. It also has four tiny legs with suction cup hands and large eyes.
Slide #17
And so basically what I was looking for was to see if there was isometric growth or allometric growth. Isometric growth would be um indicated by a slope of one and, just to give a little bit of a visual here, um it would basically mean that uh a there was uh very little proportion change. So you can see the newly hatched newt at the very top left has pretty much the same proportions as the adult, it just looks like a shrunken down version of it.
Audio Description #14
Sunshyne reads a list of two bullet points on a slide titled, "Allometric Growth." The two pictures appear over the text. First six sketches of humans lined up shoulder to shoulder from ages 0.42 years to 25.75 years. The head size appears much larger in the first human compared to that of the last, as if the head doesn't fit the size of the body. Second, a line graph compares log size of trait X to trait y. Three straight lines start at the right angle and extend out from bottom to top are: Negative allometry, Isometry, then Positive allometry.
Slide #18
And I was also seeing if allometric growth was possible um which would basically be indicative of a slope less than one or greater than one. For example, if you think of humans, there is uh disproportionate growth from the head towards the rest of the body. This is indicative by the slope being either significantly greater than one or significantly less than one. Positive allometry would be uh gracile growth, which is basically it grows longer/faster than it does grow thicker, and vice versa for negative allometry being called robust growth.
Audio Description #15
Sunshyne reads a list of five bullet points on another slide titled, Allometry Growth" then "Monoceras Growth." Finally, a scatter plot with a collection of black dots clustered in the center over three diagonal lines that extend across the graph. The top and bottom lines are green and the center line is red.
Slides #19, #20, #21
And so we are comparing this to paper research data from Kilbourne and Makovicky where they analyzed uh living African black rhinoceros. And their data shows that there is pretty much isometry uh across the board, although the femur slope is significantly more gracile, so longer than it did grow thicker. And my data was looking at Monoceras growth and Teleoceras growth. um So far I have not done the Teleoceras growth, but amongst the Monoceras growth, it shows isometry across the board although trending more gracile for radius. And so this plot is just an example of how um the data looks. So, along the x-axis is the natural log for the circumference and along the y- axis is the natural log for the length. And um inside of the green envelope is the 95% error.
Audio Description #16
Sunshyne reads a list of four bullet points on a slide titled, "Discussion" then two items on "Future Work."
Slides #22 & #23
So basically, um we discuss the end, the limbs of the Monoceras have all shown isometry and this is consistent with the results of living black rhinos, as well as other mammals. um And it'd be interesting to look at how this compares with Teleoceras because, as noted earlier, the Monoceras have longer, more slender limbs and Teleoceras has uh like stumpy, uh shorter more limbs. So, it'd be interesting to see if they also showed isometry. And for future work, um all we really need to do is add data from the University of Nebraska, Lincoln. um They have some more data over there for Monoceras. So, I can have an increase in the data set, um and then I'd have to complete uh analyzing the data for the Teleoceras from Mixson's bone bed in Florida.
Audio Description #17
A short, chubby gray rhino with huge pointy outstretched ears in a horn stub looks at us.
Slide #24
And that concludes my presentation. I'd be ha
Description
It's International Day of Women & Girls in Science! Sunshyne is one of four female paleontologists who virtually shared her latest paleontological research at Agate Fossil Beds and Badlands National Park. She studies the Menoceras, an ancient rhinoceros. This video is captioned, audio described, and interpreted into ASL. Check out our YouTube Channel to read the questions & answers that occurred live during the program. https://www.youtube.com/watch?v=degrOlMAwCk
Duration
16 minutes, 13 seconds
Date Created
02/12/2024
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