Tracking Cretaceous Birds in South Korea: Chinju Innovation City and Sangcheong-gun

Hello, Dear Readers!

When we last left our heroes, they were finishing up a long day (September 13) of laboratory and field work in Chinju (Jinju) University and Bito Island, respectively. September 14 would also prove to be an exciting field- and museum- day, full of bird tracks! Don't worry: I won't forget the non-avian dinosaur and pterosaur tracks!

Once again I'm forced to break our day into the field component and the museum component because there is just so much to talk about. This week's September 14 post will cover our field activities, and the next post will cover the spectacular Gajin Track Site.

We start off our day with a 7:30am wake-up and met Sujin for breakfast at a local Starbucks around 8:30am. After breakfast, we met Dr. Kim Kyung-soo at the hotel and drove to one of the in-progress construction sites of Jinju Innovation City. Remember in my last post, when I said that one of the similarities between studying tracks in British Columbia and South Korea is that many discoveries were (and continue to be) made as a result of industrial activity? Jinju Innovation City is a perfect example of industry significantly contributing to paleontology discoveries.

Excavations are uncovering track surface after track surface, and with a mandate to preserve national heritage, paleontologists in South Korea have to not only archive these large track-bearing blocks, but they also have to collect them! In the spirit of "necessity is the mother of invention," Dr. Kim designed a novel method for removing and transporting track blocks weighing several hundred kilograms...in one piece. Oh yes: and every picture in which you see a "KS" label on a track specimen? That specimen was collected and documented by Dr. Kim Kyung-soo.

People with visible faces: Drs. Kim Kyung-soo (left), Martin Lockley (center) and Richard McCrea (right) examining one of Dr. Kim's amazing track cradles for a large specimen ready to be removed to collections.

When we have the resources, we are going to bring Dr. Kim and his team over to visit track sites in British Columbia: I would love to see his track slab cradle technique in action!

Not all of the track-bearing surfaces are removed. One of the great approaches we witnessed in South Korea (take note, North America) is that people recognize - and act on - the value of preserving track localities as interpretive sites to educate the public. At this one construction site, two interpretive buildings are under construction for small interpretive centers.

I am just going to add an editorial note: this is the Republic of Korea. The country has a population of in a land area of 51,446,201 (with a density of 507 people per square kilometer) in a 100,210 square kilometers. Land, and space on which to develop, is valuable, and yet the Republic of Korea STILL finds ways to preserve and showcase their fossil heritage with respect. Now look to Canada. We have a population of 35,151,728 people spread over 9,984,670 square kilometers (population density of 3.92 people per square kilometer, albeit concentrated near the border with the United States.) So how come there is so much reticence towards protective buildings such as this one installed over important fossil sites? Take your time.

The track surface is covered to protect it during construction, so we pulled back the layers of tarps and thick felt-like cushioning to visit the surface.

Vertebrate ichnologists LOVE seeing surfaces like this...these are great surfaces for tracks!

We swept off portions of the track site to reveal some tracks with exquisite detail. The track type that has fascinated me (let's be honest: they all fascinate me) are trackways of pterosaurs. Yup: tracks of flying reptiles! When they weren't soaring through the air, pterosaurs walked on surfaces as quadrupeds, leaving wing finger impressions! HOW COOL IS THAT?!?

A pterosaur handprint! Guess what the loooong digit impression is from? (Psst: it's the wing digit!)

Editorial Note: You may want to Google pterosaurs. I don't blame you: they are fascinating archosaurs! However, you may encounter two websites in your search. One is called "ReptileEvolution.com" and the other is called "Pterosaur Heresies," both of which are run by the same person. Both of these sites are full of interesting artwork, but the information they provide on "radical" new ideas about pterosaurs is not supported by information from the fossils. Neither site should be a go-to site for accurate, data-supported information. Read the Tetrapod Zoology blog post on the issue.

One part of Dr. Richard McCrea's work is to refine photogrammetry techniques, particularly with small, low-relief tracks. This little pterosaur handprint is a perfect test subject!

Dr. Richard McCrea takes photogrammetry images for creating a 3D digital model of small tracks.

With a surface that preserved detail like pterosaur tracks, I was very hopeful for bird tracks. I was not disappointed! We didn't have a lot of time at the site, so this is the only definite track I could see, but where there's one, there's likely more!

This isn't the best picture (the room was under construction and unlit) but it is very birdie!

We drove to Sangcheong-gun (Sangcheong County) to check out a track site that was relatively close to the highway. It was a HOT day: the track surface was almost burning hot. It was a great contrast to the raindrop impressions we saw.

Oh yes, that's a bird track in the center of all of those rain drop casts.

This was a lovely track surface for fine details. The bird tracks were exquisite. The bird track in the center of the image above has slight digital pads and a lovely hint of a webbing impression!

You know you have a nice track surface when fine soft tissue details, like skin impressions and webbing impressions, are visible!

There's a lot we can tell about this trackmaker by looking at its footprint. One, this is a small bird (footprint length about 2.5 cm). Two, it doesn't have a well-impressed hallux (or reversed toe), so we know it didn't look or behave like a small crane or egret. Three, this bird only has a little bit of webbing between the middle and outer digit: this isn't a webbed bird like a duck. Four, this bird meandered, stopped, and started again, all over the track surface. This bird, if we were to take a time machine back to the Early Cretaceous, would have looked and behaved a lot like one of our present-day sandpipers. This was another track site exposed by industrial activity (construction of a highway), although our time machine shows us a peaceful scene of a very quiet, silty bank next to a small lake or slow-moving stream.

Also, we would have had to watch out for being stepped on by sauropods! Another thing we know from the tracks is that the sauropod came through first, and then the birds walked on the surface. We know this because the bird trackway actually walks around the sauropod track! How cool is that?

We then drove to a small cafe where we would eat what would be my favorite meal in Korea: naengmyeon, cold noodle soup! (Note: this is only one of many recipes I found online.) Most of the soups we tried in Korea had two versions, a regular version and a spicy version (I went spicy!) This is now a soup I make regularly for dinner, or at least the closest version I can make living in a remote area with limited shopping options.

Stay tuned for our visit to the Gajin-ri track!

Tracking Cretaceous Birds in South Korea: Bito Island

Happy New Year, Dear Readers!

I'm going to forgo the usual "Here are my goals for the New Year" post because...well, things are still up in the air, plan-wise. We still have no funding to continue the field documentation and excavation (a.k.a. research) of the Six Peaks Dinosaur Track Site (guest blog post on Real Scientists) near Hudson's Hope, British Columbia. This will be Year 2 of an uncertain field season. Right now, I'm just taking my work one day at a time, working on projects that I'm excited about. Some projects are research, while another is more literary in nature.

One of the projects I'm excited about is my science communication, and I must continue, Dear Reader, with my tale of Cretaceous bird tracks from South Korea!

We last left our ichnology heroes on September 13, 2017, at lunch at a Chinese restaurant after a morning of documenting tracks at Dr. Kim Kyung-soo's lab at Chinju University. We timed our lunch and travel to get from the University to Bito Island to hit the right part of the tide cycle, as our prospective field stops were all along the shoreline of the island. Doing field work in a tide-influenced area means you have to be aware of the local tide tables if you want to see outcrop. Our outcrops would be exposed during mid- to late afternoon.

The drive to Bito Island was lovely, with lots of coastal scenery (that does not photograph well at highway speeds). When we arrived at Bito Island around 2:45pm, Dr. Kim pointed out imagery of the Hare and the Tortoise, representing the Korean folktale of "The Hare's Liver." The Hare (representing the peasantry) had to be clever and quick to escape the Tortoise (representing nobility), who was tasked with fetching the liver of the Hare to cure the Dragon King. Here's a link to the story of "The Hare's Liver:" if you know of a better version, please let me know!

"The Hare's Liver." The Tortoise is likely happy because he thinks he's fulfilling his mission to retrieve the Hare's liver for the Dragon King, while the Hare is pleased that he's going to outwit the Tortoise and save his innards.

Our first stop was a possible reptilian track site. The area is a popular fishing spot, so there was good parking for the boat launches and anglers. We started our hike down to the first track site.

Strolling along one of the moorings for the small fishing boats on Bito Island.

The track site was a small exposure of finely-bedded (layered) silty sand that has some horizontal exposures. Here's Dr. Richard McCrea standing next to the track surface.

There are a great many similarities between doing fieldwork in South Korea and fieldwork in northeastern British Columbia. First, the bulk of the vertebrate fossil record for the Early Cretaceous in both areas is from the track record. There is skeletal material, but it is not common enough to tell an accurate story of life during the Early Cretaceous for South Korea and British Columbia. Second, both areas are heavily vegetated. We have to rely on either natural exposures along waterways and mountain tops, or those rocks exposed by the extensive industrial activity in both areas.

One thing we do not have in northeastern British Columbia is intertidal invertebrates occupying the track surfaces. Thankfully these snails were huddled in the cracks on the vertical part of the rock exposure and didn't hide the tracks.

Here is a close-up of the tracks exposed on the surface. They are very likely tracks of a large, Early Cretaceous turtle.

Our next stop was a larger track site that was a short car trip and a short hike away from Stop 1. It was a glorious day for a walk along the shoreline, and the scenery was beautiful.

The gorgeous coastal scenery on Bito Island.

I could look for bird tracks here all day.

Left to right: Drs. Richard McCrea, Martin Lockley, and Kim Kyung-soo, en route to the track site.

The track site is where the didactyl (two-toed) theropod tracks named Dromaeosauripus jinjuensis (Kim et al. 2012) were discovered (link to paper abstract).

We spent a little time sweeping off the small shoreline pebbles that covered the track surface.

Rich and Sujin standing behind the uncovered trackway of Dromaeosauripus jinjuensis.

Rich and our other grad student, Jason, at the Dromaeosauripus jinjuensis track site.

Here is a close-up of a section of the Dromaeosauripus jinjuensis trackway. Do you see the large theropod track stepping on the trackway?

Once we uncovered the Dromaeosauripus jinjuensis trackway, Rich got to work taking the pictures for a photogrammetry model.

Rich demonstrating photogrammetry in bright light conditions on the Dromaeosauripus jinjuensis trackway. Red arrows show the Dromaeosauripus jinjuensis tracks.

Site visits such as these are an important part of fossil heritage conservation. This trackway was described in 2012, but that doesn't mean that once it is published that it is forgotten about. This track site (and any other fossil site) will be examined every year to monitor its condition.

While the photogrammetry was taking place, I started hunting out my quarry: bird tracks! At this site, the smallest tracks we would see were those of Dromaeosauripus. We did see tracks of a small sauropod (think Brontosaurus for the trackmaker) on the same surface.

Sauropod manus (hand) and pes (foot) tracks, Bito Island. The arrow on the scale is 10 cm.

While I did not find any bird tracks at this track site, I did make a new friend. Meet (tentative identification) Scolopendra subspinipes, sometimes known as the Orange-legged Centipede.

I'm not the largest fan of encountering critters with more than six legs. I have been known to perform the Spider Dance at inopportune times. One such time was while using an outhouse in the field...admittedly not my most dignified moment. Thankfully I didn't find my new friend on my leg or in my backpack, although I did close all of the zips on my backpack after taking pictures of the centipede.

We were approaching 4:30pm when we went to the last field site for the day: a long stretch of shoreline on which large ornithopod tracks had been discovered. I immediately went into bird track mode and started with the rocks exposed near the edge of the forest.

I did find a suspicious-looking small trace, but there was not enough of it exposed for me to be sure that it was a vertebrate trace.

I also came across a medium-sized theropod track.

At this time the light was beginning to fade. Lighting plays a huge roll in seeing tracks in the field. The dimmer the light, the less likely you are to see small tracks. The best condition for seeing bird tracks in the field is a bright sunny day that casts shadows on low-relief surfaces. These were not ideal light conditions.

Dim light is not ideal for finding any track, let alone small, shallow bird tracks.

I started working my way down to the edge of the water around 6:30pm. I'll be honest: I was not expecting to find bird tracks this late in the day. I was still looking, but I knew my chances of recognizing bird tracks were slim. What caught my attention were all of the tiny hermit crabs. I knelt on to the wet, slippery rocks to try to get a picture of the hermit crabs...and my brain focused on a familiar pattern on the rock.

BIRD TRACKS!

I called people over, and we immediately started outlining the bird tracks that we could see using white chalk. Because this is a tidal-influenced area, Dr. Kim and his grad students began to salvage the track surface for removal back to the lab.

This part made me extremely nervous because the rock layer the bird tracks are on is very, but the surface came up in good condition. It turns out these were the first bird tracks to be found at this particular locality on the island. This was a good year for me finding bird tracks!

This was a full day! After we deposited the tracks in Dr. Kim's lab, we went to dinner at a sushi restaurant and ate more sushi in one sitting than I ever have in my entire life. We made it back to the Happy Owl Hotel by 11:00pm.

A very small part of the owl collection at The Happy Owl Hotel.

I downloaded all of my pictures and updated my field notes, and was definitely ready for bed at 11:30pm. The next day's adventure would prove to be just as busy, as we would visit the Jinju Innovation City track sites, and the Gajin-ri track site!

References

Kim JY, Lockley MG, Woo JO, Kim SH. 2012. Unusual didactyl traces from the Jinju Formation (Early Cretaceous, South Korea) indicate a new ichnospecies of Dromaeosauripus. Ichnos 19(1-2): 75-83.