It’s been one asteroid-impactor of a year, and most of us can’t wait for 2016 to go extinct. But it’s not been all bad: for palaeontologists there were some knock-out discoveries, including ‘three-eyed’ reptiles, and an ID for the infamous Tully monster.



We’d like to share our pick of the Top Fossils of 2016. Our choices reflect the broad range of specialities and interests we have here in The Lost Worlds Revisited blog team, so there should be something for everyone. We hope you enjoy our selection - may 2017 bring us many more such wonders!



Image of the SOA-MM4 mandible superimposed on the Homo floresiensis skull (LB1) and compared with a modern human skull from the Jomon Period of Japan Photograph: Yousuke Kaifu

Hanneke Meijer’s choices - Homo floresiensis, and dinosaur tail in amber

Despite all the uglyness that was 2016, looking at what this past year has brought us in amazing fossil discoveries makes me feel (somewhat) better. For my personal favorites, I picked two. The first one constitutes only a tiny fragment of a lower jaw and a handful of teeth, but is the culmination of years of hard work under the scorching sun in remote eastern Indonesia. This tiny jaw represents a small species of hominin, 700,000 years old, and is presumed to be ancestral to Homo floresiensis, the ‘hobbits’ of Flores. Stone tools alongside the bones of extinct animals such as pygmy elephants and giant rats have been found in the So’a Basin since the 1950s, but of the stone-tool makers, no sign. Until last year, when the team finally came across hominin bone remains. As tantalizing as the fragments are, they raised even more questions about the origin of the little people of Flores.

Dinosaur tail complete with its feathers trapped in a piece of amber - found on a market in Myitkyina, Myanmar, last year - showing the tip of a preserved dinosaur tail with feathers. Photograph: R.C. McKellar/Royal Saskatchewan Museum (RSM)/Handout via REUTERS

And then there was the dinosaur tail. The first evidence for feathered dinosaurs came in the late 1990s in the shape of fuzzy dark outlines around fossils and feather attachments sites on bones. Later on, exceptionally preserved fossils from China showed clear feather impressions, and most paleontologists now agree that dinosaurs sported a fuzzy coat. But this new specimen, the first piece of dinosaur in amber ever, shows for the very first time evidence for feathered dinosaurs not in a flattened 2D arrangement, but in three beautiful life-like dimensions. Being face to face with an animal trapped in amber is almost as if a wormhole opened and you’re staring down into earth’s history. Right in front of you is a part of a dinosaur so very life-like, as if it had died yesterday. If that does not lighten up your day, I don’t know what will.



Dave Hone’s choice - Dracoraptor hanigani

This little carnivorous dinosaur made a big splash when it was discovered last year at Penarth near Cardiff, but the paper describing and naming it came through in 2016. There are actually lots of dinosaurs in the UK, but too many of them are very incomplete skeletons which are not always very informative and most are (in Mesozoic terms) from relatively recent species.



This is an artist’s impression of Dracoraptor hanigani. Illustration: Bob Nicholls/http://paleocreations.com

Dracoraptor bucks both trends being from the very earliest Jurassic making it right around 200 million years old, and being known from quite a bit of skeleton. The specimen so far has most of a skull, most of the limbs and some vertebrae, but more of it was recently recovered so our knowledge will grow. The animal would have been about 2 m long, but as it was a juvenile its final size isn’t known. Still, few members of the group to which is belongs (the coelophysoids) got to be very big so it may never have been a titan when full grown.

Elsa Panciroli’s choice - Palaeoxonodon ooliticus

They say good things come in small packages: at the start of 2016, the stunning little jaw of a 166 million year old mammal was published from the Isle of Skye, Scotland.



Scotland represents a new frontier in British palaeontology; nowhere more so perhaps than Skye. While I must admit bias in my top fossil choice (I’m a native of the Highlands and Islands, and the authors are fellow field workers), there’s no denying this is an underappreciated piece of palaeontological perfection.

The small jaw of the early mammal Palaeoxonodon (top), the digital reconstruction using CT scans (middle), and the enlarged 3D printed version (bottom). Photograph: Roger Close

This teensy jaw, no bigger than a 20 pence coin, looks inconspicuous, but when enlarged and printed in 3D – a process made possible by CT-scanning and digital reconstruction – the ferocity of this insect guzzler’s dentition is on par with any fearsome dinosaur. Close and colleagues’ discovery is not only beautifully preserved, but proves that several individual teeth thought to belong to different species from Jurassic sites in England, are all from this single species: Palaeoxonodon.

It’s unlikely that these are our direct ancestors, but they are important cousins on our increasingly bushy Jurassic family tree. It’s a time in the history of mammal evolution we know little about, but recent research indicates mammals were exploding in diversity - and importance - in their ancient ecosystems. People go bonkers over giant reptiles, but the real wonder (and great scientific importance) is in such micro-vertebrate fossils. There will undoubtedly be many more miniature wonders to come out of Skye in 2017.

Susannah Lydon’s choice - Radix carbonica

My top fossil of 2016 has to be Radix carbonica, a 300 million year old plant root tip with recognisable stem cells. The cellular detail preserved in a concretion from the Lancashire coal measures shows a plant root caught in the act of stem cell proliferation, with an anatomy which is different from that seen in any modern plant.



The oldest fossilised remains of an actively growing root meristem, named Radix carbonica (Latin for coal root). Photograph: Alexander (Sandy) Hetherington (Department of Plant Sciences University of Oxford)

If root anatomy in the Carboniferous Period was much more diverse than we thought, what else are we missing at the cell scale in the plant fossil record? This discovery brings together the worlds of palaeobotany and developmental biology to great effect. Evo-devo research has been a fruitful approach in other areas of palaeontology (early tetrapod evolution is a great example), and it is great to see more and more plant evolution researchers also taking this approach. The fossil material in this study was collected and prepared a century ago, and shows the importance of looking after our museum collections: there’s always something new to learn from old fossils.

Mark Carnall’s choice – smelly cephalopods

My fossil pick for this year are the twenty deceased common octopuses (Octopus vulgaris) and the twenty European squid (Loligo vulgaris) bought from a fish merchant in Bristol by the team behind the paper Buoyancy Mechanisms Limit Preservation of Coleoid Cephalopod Soft Tissues in Mesozoic Lagerstätten (Clements et al. 2016). They aren’t strictly fossils but they certainly served in the interest of palaeontology in a smelly and interesting example of experimental palaeontology.



Thomas Clements with an octopus ‘participant’ getting prepped for an experimental palaeontological experiment. Photograph: Thomas Clements/Caitlin Colleary

As I mentioned in an earlier Lost Worlds Revisited blog post, cephalopod soft tissue fossils are extremely rare. There are a handful of octopus and vampire squid body fossils but not a single example of ‘true’ (Teuthid) squid or cuttlefish fossil is known (well no body fossils – we have cuttlebones, squid jaws and statholiths). However, molecular and phylogenetic data indicates that these groups evolved around the same time as the octopods in the past).

The team examined some of these preservation biases by rotting the squid, octopus and fish carcasses in jars of artificial seawater over 14 days to see how the breakdown of the bodies affected the microenvironment, in particular, if the pH was getting low enough to enable key fossilisation processes. The conclusion? The higher ammonia content in squid tissue - which keeps them neutrally buoyant in life - buffers the pH drop and reduces the chance of these organisms fossilising.

Of course, this doesn’t mean that a squid or cuttlefish body fossil will never be discovered, but these would-be-dinner specimens have helped explain the mysterious absence of fossil evidence of these two groups, which we now have a basis for knowing is not conclusive evidence of absence.

References

Clements, T., Colleary, C., De Baets, K. and Vinther, J. (2016) Buoyancy mechanisms limit preservation of coleoid cephalopod soft tissues in Mesozoic Lagerstätten. Palaeontology. doi:10.1111/pala.12267

Close, R. A., Davis, B. M., Walsh, S., Wolniewicz, A. S., Friedman, M. and Benson, R. B. 2016 A lower jaw of Palaeoxonodon from the Middle Jurassic of the Isle of Skye, Scotland, sheds new light on the diversity of British stem therians. Palaeontology, 59, 155-169.

Martill, D. M., Vidovic, S. U., Howells, C. and Nudds, J. R. 2016 The Oldest Jurassic Dinosaur: A Basal Neotheropod from the Hettangian of Great Britain. PLOS ONE. 11 (1): e0145713. doi:10.1371/journal.pone.0145713

Xing, L, McKellar, R.C., Xu, X, Li, G, Bai, M, Persons IV, WS, Miyashita, T, Benton, MJ, Zhang, J, Wolfe, AP, Yi, Q, Tseng, K, Ran, H and Currie, PJ, 2016. A feathered dinosaur tail with primitive plumage trapped in Mid-Cretaceous amber. Current Biology, 26: 3352–3360