What a week it's been for palaeontology in the news, especially related to taphonomy! There's a new paper on the taphonomy of the Cleveland-Llyod Dinosaur Quarry, a paper describing featherless patches of skin on Tyrannosaurus rex, and now a mid-Cretaceous 'bird' (avialan) hatchling has been found encased in Burmese amber!

The hatchling is from a now-extinct group of avialans called enantiornithines. It is a 'bird' in the broadest sense, but just not from the same lineage that modern-day birds belong to (the neornithes).

The preservation of this specimen is fantastic. The right foot is clearly visible with the podotheca, claw sheathes, and feathers still intact. More difficult to see is the head and neck of this hatchling, but with the help of micro-CT and x-ray, Xing et al. (2017) show that they are present and also well preserved.

How did this hatchling end up in a lump of amber? Amber is preserved tree sap or resin, and while tiny animals such as insects are normally the victims of sticky-sap entrapment, small vertebrates such as frogs, lizards, and (as described by the same authors in a previous paper) a small dinosaur or bird tail have also been known to get caught in ancient resin. As for this hatchling, the authors propose that only part of the body was covered in resin (either during or soon after death), with the rest of the body remaining uncovered and exposed to the elements. Later, a second resin flow covered the remainder of the body.

Xing, L., O'Connor, J. K., McKellar, R. C., Chiappe, L. M., Tseng, K., Li, G., Bai, M., 2017. A mid-Cretaceous enantiornithine (Aves) hatchling preserved in Burmese amber with unusual plumage. doi: 10.1016/ j.gr.2017.06.001

I had a chat with Greg Wah and Dan Beeston at the podcast Smart Enough to Know Better about the taphonomy of two beautifully preserved dinosaur fossils in the news: Zuul crurivastator, a new ankylosaur from Montana named after a Ghostbusters character (image below left), and a beautifully preserved nodosaur from the oil sands deposits of Alberta (image below right).

​Have a listen to Episode 126 here:
​https://smartenough.org/episode/126.0

​(In the podcast I talk about a giant tortoise that floated in the the ocean for many months and survived [PDF], but I called it a 'turtle'. My bad!)

EDIT (30/5/2017): The Dinosaur Expeditions centre, where the fossil will be displayed, have offered the following equally likely explanation for this footprint-like impression: 
"Localised compression fractures, deformation of surface & underlying cancellous bone matches a tridactyl print. Parsimonious explanation." (via this tweet).

A dinosaur footprint has been found embedded on the surface of dinosaur backbone, according to the Isle of Wight County Press.

It seems extremely improbable, but it isn't impossible. In taphonomy, we always consider the effect of trampling on decomposing bodies: if a body is laying near a lake or other water source, then it is likely that many other animals will be passing through that area and accidentally walk over the body. This can crush and scatter bone, but I've never heard of a foot landing precisely on the body (centrum) of a vertebrae and leaving a footprint behind.

In this case, it seems a small theropod (meat-eating) dinosaur has walked over the top of a decaying sauropod (long-necked) dinosaur carcass, at one point stepping precisely on a vertebra.

​​From what I can see in the photograph, it appears that there is still some mudstone covering the centrum. I thought perhaps the footprint was in the mud layer covering the bone, but the articles I've read suggest that the theropod foot crushed the bone. The rest of the vertebrae has been preserved quite well. This sauropod must have been decayed enough so that the vertebrae had disarticulated and lay centrum-side up, with the centrum and bone marrow softening and rotting while the rest of the bone remained fairly solid before it was trodden on. Again, improbable, but not outside the realm of possibility.

I also considered whether the footprint was pressed into a muddy bank first, and the bone later laid on top of it, 'sticking' the two together. However for this to be the case, the footprint on the bone would have to be a cast of the original print and would appear raised off the surface of the bone, rather than sunken in like a mold.

I look forward to seeing a thorough examination of this specimen, as if this impression is a theropod footprint, it shows direct evidence of this small theropod and large sauropod co-existing in the same part of the ancient Wealden landscape.

References
County Press reporter, 2017. "Unprecedented dinosaur discovery made on the Isle of Wight". Isle of Wight County Press. URL: http://www.iwcp.co.uk/news/news/unprecedented-dinosaur-discovery-made-on-the-isle-of-wight-315188.aspx Accessed Sunday 28th May​, 2017.

Dinosaur Expeditions (DinosaurInfo). "Localised compression fractures, deformation of surface & underlying cancellous bone matches a tridactyl print. Parsimonious explanation." 29th May 2017, 5:48pm. Tweet.

A white-tail deer has been caught on camera eating human remains.

The remains were part of a taphonomic experiment at the Forensic Anthropology Research Facility (FARF) in Texas, USA, where they were studying what types of scavengers visit human carcasses. They were left uncovered with cameras photographing anything that came to scavenge them. Imagine being the person reviewing those images, expecting to see coyotes, or racoons, or turkey vultures, and instead uncovering the first recorded instance of human bone-munching deer.

​This is not the first case of a classically herbivorous (plant-eating) animal eating bones from rotting carcasses--a behaviour called osteophagy--but it is the first time a deer has been captured nibbling on human remains.

Herbivorous animals practice osteophagy when they need more phosphate, calcium, and other nutrients in their diet. Porcupines, giraffes, cows, and even tortoises have been seen chewing on bones, most often already dry and easily accessible bones like ribs.

When recording traces of tooth-marks on bones in the modern, archaeological, or palaeontological record, it is important to remember that not all scavengers that interact with carcasses are trying to consume flesh. And that while carnivorous scavengers typically eat soft tissue and fresh bone leaving behind puncture holes and pits, bone-eating herbivores chew on the ends of older bones with teeth normally used to eat plants leaving behind long scores and forked splinters.

References
Meckel, L. A., McDaneld, C. P., Wescott, D. J., 2017. White-tailed Deer as a Taphonomic Agent: Photographic Evidence of White-tailed Deer Gnawing on Human Bone. DOI: 10.1111/1556-4029.13514.

The day has finally arrived... I am now Dr Caitlin Syme! My PhD thesis went through the various stages of PDF upload, revision, re-upload, approval, FINAL upload, and then I received the letter I'd been waiting for...

I'm looking for more 'normal' paid work while I apply for post-docs and museum-related jobs, but for now I can breathe a little easier. Thanks for joining me on this PhD journey, and I hope you continue to find these posts useful for understanding both PhD and post-PhD life. And to keep enjoying fossil and taphonomy related news, of course!

Warm, dark-brown, sticky tar oozes out of the ground at Rancho La Brea in California, creating deep lakes of asphalt belching forth bubbles of methane. These asphalt lakes, or tar seeps, are particularly hazardous to animals passing by, trapping and swallowing up carcasses whole. And the tar seeps at La Brea have been trapping animals and luring predators to their deaths for 50, 000 years.

Rancho La Brea has produced around 3 million Pleistocene and Holocene fossils belonging to hundreds of vertebrate, invertebrae, and plant species, including dire wolves, sabertooth cats, mammoths, ground sloths, hawks, geese, owls, snakes, frogs, scorpions, spiders, ants, beetles, poison oak, juniper, red cedar, and thistle. The majority of fossils belong to mammalian predators that probably attempted to eat rotting carcasses stuck in tar, then found themselves similarly stuck in the asphalt ooze, then died and decayed thus becoming new lures for passing predators and scavengers. But no-one is quite sure how long decay might take before the carcass becomes a less appetising jumble of asphalt-soaked bones, and if those bones separate from each other and are pushed along by currents while floating at the surface, or disarticulate after sinking to the bottom of the tar seep.

A new paper by Brown et al. (2017) explores these questions by using actualistic taphonomic experiments. The authors took limbs from carcasses of a modern mammalian predator, the bobcat (Lynx rufus), and placed them in wire cages that were then lowered into tar seeps in Chivo Canyon, California. Over 10 weeks, they removed a limb from the tar seep every 2 weeks and noted how much soft tissue had decayed, as well as the types of microbes feeding on the flesh and living in the tar.

​They found that decay occurred surprisingly quickly and surmised that a rich bacterial community exists in the tar seep, ready and waiting to consume flesh. Their microbial tests showed the bacteria did not hitch-hike into the tar seep on the bobcat carcasses. We know that hundreds of petroleum-eating bacteria species already exist in the tar seeps - they produce the methane bubbles - but it now seems that there are bacteria living in these tar seeps that specialise in eating organic material.

The authors conclude that modern bobcat limbs take around 2-3 months to fully decay in tar seeps. It appears that without the presence of the experimental wire cage, their bones would disarticulate (separate) after only a few weeks. The authors propose that the majority of decay and disarticulation therefore occurs at or just below the surface of tar seep, with single bones then being buoyed along by wind or water currents. The authors admitted that while these smaller limbs portions immediately sank into the tar, larger bodies may float at the surface while decaying with parts of the body exposed to the elements, and plan to conduct more actualistic experiments using whole carcasses in the future. I'd like to see more data on the temperatures of the tar seep, and how that might speed up or slow down decay depending on the types of bacteria present. Overall, this is a very thoughtful and interesting paper, so check it out (if you can get past the paywall).

Brown, C., Curd, E., Friscia, A. 2017. An actualistic experiment to determine skeletonization and disarticulation in the La Brea tar seeps. PALAIOS, 32:119-124.

This is why we want equality, and equal representation for women in science... so we can JUST TALK ABOUT OUR RESEARCH like anyone else!

Have you ever stumbled across a bone, perhaps while walking around the city or countryside, and wondered what type of bone it is, and what animal it belonged to? Maybe you're unsure if you're looking at left-over soup bones, or have found the first evidence of a rare species in your area. If so, have a look at this new database of bone photographs called BoneID.

The database is in its early days, so at the moment it only has images of mainly North American animal bones. But is still interesting to browse the website and see the variation in bone shapes between alligators, owls, and raccoons. You can always search their Facebook group page to see if other bone enthusiasts can help you with your bone identification.

If you have any images of animal bones you can send to the website creator, photographed from standard anatomical angles (anterior, posterior, cranial, caudal, lateral, inferior, superior, etc.), then be sure to let them know! I have quite a few saltwater crocodile bone photos I'll be sending their way...

This crisp and dynamic illustration of a Protoceratops is one of the featured dinosaurs from the Institute for the Study of Mongolian Dinosaurs (ISMD), established by palaeontologist Bolortsetseg Minjin (who has been instrumental in repatriating fossils stolen from the Gobi Desert for auction in the USA).

Two weeks ago, a group of scientists started chatting on Twitter about carnivores and their prey, and started sharing gory pictures of carcasses. Things got a little (lightheartedly) competitive, and after Julien Fattebert shared a photo of a leopard cub killed by lions, and added the hashtag #bestcarcass, a Twitter battle was born.

Since then, Twitter users have shared fascinating, strange, and sometimes disturbing images of decaying animals from all over the world in weird and wonderful poses.

Listed below are my top 10 picks (in no particular order) for some of the most taphonomically interesting #bestcarcass contenders. And, unsurprisingly, some people may find the follow images disturbing: click 'read more' at your own peril...