Early Bird (Tracks) in British Columbia: Introducing Paxavipes!

Hello, Dear Readers!

It's been awhile since I've dusted off the Blog: it's been a stressful time for the Strange Woman, and while Tolkien made the apt observation that harrowing tales make the best stories (The Hobbit), I'm bored of thinking about it, and would much rather talk about paleontology! Our research group had a fun time publishing on my favorite subject: BIRDS! Specifically, we have a recent paper in Cretaceous Research on a new avian ichnotaxon (footprint type) from the Peace Region of British Columbia!

Please join me in welcoming Paxavipes (Peace bird footprint, in reference to the Peace Region) babcockensis (in reference to Mount Babcock, the mountain on which the specimen was discovered) to the ichnological family! OK, that's not taxonomically accurate, as Paxavipes is also part of a new ichnofamily. Bear with me.

Bird tracks have been known from British Columbia, and specifically the Peace Region, since their scientific debut in 1981 with Aquatilavipes swiboldae (Currie, 1981). This specimen was recovered as part of the salvage and study operation performed by the then Provincial Museum of Alberta before the completion of the Peace Canyon hydroelectric dam. The area was so well-known for its palaeontological heritage that it was officially designated a Provincial Historic Resource in the 1930s. Today you would need gills and fins (and a whole bunch of de-silting equipment) to see these localities, as they are now underneath what is known as Dinosaur Lake. The type slab for Aquatilavipes swiboldae now resides in the Royal Tyrrell Museum of Palaeontology (RTMP). At the time of its scientific write-up, it was the earliest known bird track type, being from Gething Formation deposits that are Lower Cretaceous (Aptian, approximately 125 - 113 million years old). Since then, no bird footprints have been published on from British Columbia...until now.

The rock slab on which Paxavipes are preserved was discovered in 2005 by a (then) doctoral student Curtis Lettely (University of Alberta). The slab was discovered in an area locally called The Boulder Gardens. The Boulder Gardens is series of hiking trails leading outdoor adventurers through a gorgeous sup-alpine terrain of visually stunning sandstone erosional features. Check out more information on the PDF here. Boulder Gardens is within the boundaries of the newly established Tumbler Ridge Global Geopark. The Boulder Gardens showcases rock from the Boulder Creek Formation, which is Early Cretaceous (middle-upper Albian, approximately 100 to 105 million years old.)

This was an interesting slab. The rock slab was found vertically embedded in eroded rubble and dirt, and what was exposed was covered in many lichen colonies. Lichen is hard, crusty, and hides any surface details it covers. We could see that there were small theropod footprints (Irenichnites-looking prints), and a few visible bird footprints, but did not know how many prints were preserved on the surface, or anything detailed about their shape, with all of that crusty lichen. That lichen had to go...

Fig. 2 of PRPRC 2005.001.015 from Buckley and McCrea (2009). It's easy to see which part of the slab was exposed for lichen colonization.

...but carefully. Lichen is a resistant organism - what else can you expect when fungi and cyanobacteria form an alliance (symbiotic relationship)? Mechanically scraping off the lichen was not an option, as that would have risked mechanically scraping the track surface and the prints it preserved. After trying out a few different chemicals, we saw that a dilute bleach solution effective at breaking down the lichen to a point where it could be gently brushed away with a soft toothbrush. The technique worked so well that it became the topic of my first first-author publication (Buckley and McCrea, 2009).

Once the lichen was removed, the surface was revealed...and what a reveal! A grand total of 72 bird footprints were visible, which enabled us to make out five trackways - series of footprints made by one bird walking from Point A to B. Single footprints are like an isolated bone or tooth - they give us good information, but not as much as a whole skeleton does. Trackways are like the whole skeleton.

Fig. 4 from Buckley and McCrea (2009) So many bird footprints were visible once the lichen was removed!

Another cool "after lichen" reveal was that the small theropod footprints had tiny skin impressions on them! Check out the teeny tiny pebbly texture:

Fig. 6 from McCrea et al. (2015). Skin impressions such as these give us a good idea of what the soles of dinosaurs' feet looked like. These tubercles likely acted like the treads on our running shoes.

Back to the birds. Since we have trackways, we could tell left footprints from right footprints, but not easily. There was something odd with these particular bird footprints. The usual case for bird footprints is that the outer toe is much more splayed away from the middle toe than is the inner toe (or the toes have a roughly equal amount of splay). These footprints were strange in that the inner toe was more splayed than the outer toe. It wasn't just one or two footprints out the 72: it was the majority of the prints.

Fig. 4 from McCrea et al. (2015) showing the holotype trackway - see the wider splay between the inner digits?

Something was up. There is a bit of natural side-to-side wiggle potential in bird toes, and modern bird footprints can show a big differences in toe splay (70 degrees to 140 degrees between the outer digits), but a consistently larger splay between the inner (digit II) toe and the middle (digit III) toe is not common in Cretaceous avian bird footprints. The only other bird footprint type that shows this toe arrangement is Barrosopus slobodai (Coria et al. 2002) from the Late Cretaceous of Argentina. Because these two footprint types are unique when compared to all other Mesozoic bird footprints (but different enough to still be considered separate footprint types), we formed a new ichno (footprint) family of bird prints called the Paxavipedidae. Any new three-toed bird footprint (no hallux) with consistently wider splay between digits II and II than between digits III and IV and thick digits can be assigned to this new footprint family.

As an ichnologist, when I see a repeated footprint shape or toe arrangement within all that natural variation, I begin to think about the shape of the foot. Specifically, I think about the features of the skeleton that made that footprint shape possible. Looking at modern birds, Paxavipes and Barrosopus prints are very close in shape to footprints of the Killdeer (Charadrius vociferus).

I love this image by Ryan Hodnett, found on Wikipedia. No, Killdeer are not some strange Octo-Bird: those are young Killdeer hiding under the parent.

Looking at the foot bones of a Killdeer (welcome to my thesis!), the end of the metatarsals (the lower part of the "leg" of the birds that you see hiding in the above image) are shaped in such a way that the inner toe (when attached) is going to be more splayed than the outer toe! Footprints may not always match the skeletons of feet perfectly, since living feet are covered with skin and muscle. In some cases, like with two-toed dromaeosaur trackways, there are features of the animal's skeleton that are expressed in the footprints. When we find these features, we have a good chance of predicting what the skeletal foot of these track-makers would look like. We haven't yet found the track-maker for Paxavipes, but we have a good chance of recognizing it when (if) it is found! [NOTE: This doesn't mean that Killdeer were around in the Early Cretaceous: this means that a bird with a foot shape that resembles a foot of a Killdeer was around in the Cretaceous.]

Next time you are walking along a beach and see little brown and white shorebirds skittering along the edge of the water looking for yummy invertebrates, think about a Cretaceous shoreline: you would likely notice the dinosaurs first, but the small shorebirds still made quite an impression!

References:

Buckley LG, McCrea RT. 2009. The sodium hypochlorite solution for the removal of lichen from vertebrate track surfaces. Ichnos 16(3):230-234.

Coria RA, Currie PJ, Eberth D, Garrido A. 2002. Bird footprints from the Anacleto
Formation (Late Cretaceous), Neuqu en, Argentina. Ameghiniana 39(4):453-463.

Currie PJ. 1981. Bird footprints from the Gething Formation (Aptian, Lower Cretaceous) of northeastern British Columbia, Canada. Journal of Vertebrate Paleontology 1(3-4):257-264.

McCrea RT, Buckley LG, Plint AG, Lockley MG, Matthews NA, Noble TA, Xing L, Krawetz J. 2015. Vertebrate ichnites from the Boulder Creek Formation (Lower Cretaceous: middle to ?upper Albian) of northeastern British Columbia, with a description of a new avian ichnotaxon, Paxavipes
babcockensis ichnogen. et isp. nov. Cretaceous Research 55:1-18.

2013 To-Do List: Update 1

Hello Dear Readers!

As I brush the webs of disuse off of my blog (and hope there are no digital spiders lurking in the corners), I thought I would fill the gaps between some of the interesting posts I have planned (interviews, ichnology, upcoming field work) with a short update on my 2013 To Do List.

A. Academic
I have to say that I am off and running on this resolution! I have four papers either in press or in review on which I am either first or second author. There are others where I am the tertiary (or lower) author, but I won't count those right now. Three are in vertebrate ichnology, and one is...wait for it...are you sitting down?...are you bracing yourself?....MY M.SC. THESIS!

How long ago did I get my M.Sc., you ask?

2009.

It took you THAT long to submit a simple M.Sc. thesis?!? I am a Northern Saw-whet Owl, and you should be ashamed of your lack of work ethic! www.allaboutbirds.com

I accept your scornful and disapproving gaze, Northern Saw-whet Owl. Yes, it took me an embarrassingly long time to put a stake in the heart of that undead creature. I could lob excuses around (and I think I have some good ones) but to be painfully honest, every time I opened up the file to work on it a wave of ennui and self-reproach would wash over me. Couldn't my time be better spent on that grant proposal, cataloging fossils, that paper with five coauthors, or my Ph.D.? I've learned that there is always something that I should be doing instead of research, and the trick is to find a balance between what I HAVE to do and what I WANT to do. I now take two days out of the week that are purely research and writing. The other five I sacrifice to the Gods of Administration. That bit of balance allowed me to finally get the M.Sc. research in to review.


B. Athletic
This is where my plans took a huge hit. Between getting my vision surgically corrected and having to pay the piper for tax time, plus the increased time commitments of the upcoming Geopark Proposal Symposium we are holding this July, there was no way I could logistically and financially make it to the Soke Cup competition. Nevertheless, I am still training hard to improve my techniques in karate, and now that the weather is finally warming up I can transition from indoor elliptical workouts to outdoor running (I have the cold tolerance of a hot-house orchid). I am still a snooze button junkie, but I have reduced my refined sugar intake considerably. Small steps.

What are you doing, writing about athletics and such piffle? You have work to do!

Yes, yes, Sheldon, you are correct as always: I do have several things I should be doing right now, one of them being a volume related to the Geopark.

I will sign off to appease the various statues and owls who insist on pinning me with their judgmental eyes.

Is that okay with you, Northern Saw-whet Owl?

Yes, that is quite acceptable. Just don't wake me. www.ofo.ca

SAS

The 2013 To Do List

Happy New Year!

Our New Year's festivities are usually low key. We give the Gods of the Old Year one last chance to finish us off by feasting upon the most evil of all dishes: homemade alfredo sauce and bread sticks. We only do this once a year because a good alfredo sauce is made with heavy cream, egg yolk, and copious amounts of hard cheese. I doubt that the six cloves of garlic do much to counteract the aorta-clogging madness that is alfredo sauce. Eating this dish more than once a year would inevitably bring about an apocalypse of the circulatory system.

This Feast to end all Feasts results in one or more people joking "That's it. Tomorrow I begin my New Year's diet." At least, those not already in a cheese-coma make that joke. Those of us existing in a state of semi-sentience merely digest and exude garlic. If we live to see tomorrow we count ourselves as among the fortunate. Take that, Gods of the Old Year!

New Year's Day is the time for making resolutions. We see the date of 01/01 as a fresh start. We want to make lifestyle changes that are dramatic enough to make an obvious positive difference in our lives, yet not so dramatic as to be unattainable. Let's be serious: I am not going to wake up on 01/01 and immediately run 15K if I have never laced up a pair of running shoes in my life. I am not going to write and submit 20 papers in a month. Attaining my black belt by October? I don't think so. There is nothing wrong with having big dreams and large goals. We just need to remember, when making our Grand New Year's Eve Proclamations, not to automatically set ourselves up for failure. Keep those goals realistic: all that matters is that the change you want to make is meaningful to you.

With that in mind, I have completed my 2013 To Do List. I plan to attack each item on this list with great resolve.

THE 2013 TO DO LIST

A. Academic
1. Publish those papers, dammit!
I know I am not the only paleontologist with a folder on my hard drive named "Papers In Progress". This folder is both my ally and my nemesis. It contains "manuscripts" consisting of merely a title and a few disjointed thoughts. However, this folder also contains several projects that are near completion...or they would be if I would just make myself sit down and put them out of their academic misery. These are the projects that Andy, when blogging at the Open Source Paleontologist (Andy now blogs at the Integrative Paleontologists), would prompt the paleontology community to excavate from the trenches of the "Papers in Progress" folders, dust off, and expel from Publication Purgatory.

In total, I have four ichnology papers, two tooth papers, and one osteology paper that I can realistically finish in 2013. The "last modified on" descriptors for some of these documents is embarrassing (the most shameful one is 2008), but there is nothing stopping me (except me) from graduating these manuscripts into my small (but growing) "Papers Submitted" folder.

2. Complete several thesis chapters!
It is not just a happy coincidence that at least 3/4 of the papers in my "Papers in Progress" folder are thesis-related. I love interconnected resolutions!

B. Athletic
3. Be in the best shape I can be for the 11th ICKF 2013 Soke Cup.
I may have mentioned before that I am in karate. This year is the 11th International Chito-ryu Karate-Do Federation Soke Cup, an international tournament for those who study Chito-ryu karate-do. This year the tournament will be held in Hong Kong, and I will be able to participate. This means that I have to be in great shape. I don't want to embarrass my Sensei, the dojo, and the country by being the flabby Canuck who gets winded and passes out in the middle of a match. I am not in poor physical shape, but there are parts of my current diet and exercise routine that need improvement. One, I am a notorious snooze-button junkie. This has derailed more workouts than I care to remember. Two, I am a sugar junkie. Chocolate and fancy coffee drinks are to me as the calcaneum and astragulus were to Achilles. Three, thanks to years of university life, I have trained myself to be a night owl. Heck, it's 2:00am and I am updating this post! So, in the interest of my training, I am resolved to (from this post forward) get to bed at a reasonable hour, use any form of training instead of a snooze button, and use alternatives to sugar snacks while I am working on resolutions #1 and #2.

Resolutions are promises to replace bad habits (i.e. staying up until 2am while eating a Rice Crispy bar) with good habits (i.e. getting up early to take advantage of the many cross country ski trails in this area). The only way we can form good habits is to choose to do the good habit so many times that it becomes part of our daily routine. We simultaneously have to choose to reject bad habits until we forget that we ever did them in the first place. Good habits have to be repeated until they become regular habits.

I'll keep you posted on the progress of establishing my resolved good habits as part of my regular life, and I'd love to hear about the good habits you resolve to develop! Good night...good morning...oh, heck, good 2am!

SAS