So, we made it through 2014. I would say that it’s been a long year, but as I get older that becomes less and less true, and the years seem to fly by before I know it. For me though, 2014 has been a great year. A year of change, and a year of realising some of my biggest dreams. 2014 will always be the year that I was offered a place at Oxford to study for my DPhil. As any academic should know, finding funding was not an easy task, and I had waited so long for this opportunity; I couldn’t be happier to be back in academia! So what has happened in this field I love so much in the last 12 months? What’s new in Palaeontology?
With every passing year palaeobiology becomes an ever more exciting area of science to work in, and this last year has been no exception. From dissecting permafrost mammoths, to the ‘golden age of dinosaur discovery’, 2014 has kept us on our toes from start to finish! These are my top 10 breakthroughs in palaeobiology of 2014 (in date order):
- Evidence That Placental Mammals Originated Before the K-Pg
The year got off to a controversial start in January, with a paper  that disagreed with previous work  on the timings of origins for placental mammals. O’Leary et al  argued for an early Cenozoic origin of placentals, based on fossil occurrence dates, while dos Reis et al found that combining fossil and molecular data places their origin in the Cretaceous, pre-dating the Cretaceous-Palaeogene (K-Pg) extinction event. The second study  disagrees with the first  because the authors felt it was misguided to use only fossil data in their analysis, as the fossil record is fundamentally biased by sampling. Many people think that fossil occurrences should be used only as an upper age bound for molecular clock analyses because the record is too biased to be used in any other way. It is true that the fossil record is biased by preservation potential and sampling, and this should always be taken into account when using raw fossil occurrence dates, but it is hard to know just how unreliable it is (one thing we should bear in mind is that it only takes one fossil occurrence to push a lineage origination date back in time). This difference in results between the two studies isn’t only important for researchers looking at mammal evolution across the K-Pg (as I am!), but also for the wider palaeontological community. As we move forward, we must work toward reconciling the different time estimations given by fossil and molecular data, and aim to use both to constrain a reliable date for the evolution of many animal lineages.
Please see *doi:10.1098/rsbl.2013.1003* and *doi:10.1126/science.1229237* for more information.
- New Cambrian Fossil Site Uncovered
February saw the discovery of a new site of wonderfully preserved Cambrian fossils (see images 2-5) . The site lies in Canada’s Marble Canyon, and is part of the same Burges Shale Formation that yielded over 200 species more than 100 years ago. In just two weeks the team had found 15 new species, giving us yet more insight into this exciting and extraordinary point in evolutionary history. I look forward to hearing more about these animals in the following years.
Please see *doi:10.1038/ncomms4210* for more information.
- Finding The First Jaws
In June, a primitive fossil fish, found close to the Marble Canyon site explained above, was described and published in Nature . This fossil is Cambrian in age, and sheds light on some of the earliest evolutionary steps toward gnathostomes, or ‘jawed vertebrates’. The organism, named Metaspriggina (see image 6), has been phylogenetically placed as a stem vertebrate as it possesses a wide range of vertebrate features such as ‘a notochord, a pair of prominent camera-type eyes, paired nasal sacs, possible cranium and arcualia, W-shaped myomeres, and a post-anal tail’ . Metaspriggina also has gill arches preserved. The first of these structures, located closest to the head, are the structure that later evolved to form the jaws in vertebrates. This is the first time these structures have been observed so early in the fossil record, and for that reason Metaspriggina makes it into my top 10 list!
Please see *doi:10.1038/nature13414* for more information.
- Early Skeletal Animals Built Reefs
Reef-building is an important step in the history of life on Earth. It is an example of co-operative behavior between organisms, where individuals can gain protection and ‘enhance feeding efficiency’ . In June of 2014, a paper demonstrated that reef-building was practiced among the earliest skeletal animals . These animals were called Cloudina (see image 7), and they cemented themselves to one another to form reef structures. These Cloudina reefs were found in Namibia, and are 548 million years old, a whole 7 million years older than reefs previously assumed to be the oldest examples.This find suggests that skeletal animals began building reefs prior to the Cambrian explosion, an event that was, until now, thought to have driven reef-building behavior. This could suggest that organisms were responding to ecological pressures such as predation even in the Precambrian!
Please see *doi:10.1126/science.1253393* for more information.
- Feathers Found on an Ornithischian Dinosaur
For years, people have been debating whether feathers were an ancestral or derived trait within the dinosaur clade. Late in 2013, palaeontologists suggested that scales were most likely to be the ancestral trait for dinosaurs, and that feathers must have evolved later . Many scientists believed that feathers evolved in the Theropod lineage, but were not present in the Ornithischia or Sauropodomorpha clades. Up until now, filamentous structures found on Ornithischia dinosaurs have been widely debated but in July of 2014, an Ornithischian dinosaur from the Jurassic of Siberia was found with both scales and feathers . The animal, Kulindadromeus zabaikalicus, has both monofilaments and more complex featherlike structures across its body (see artists impression, image 8). This discovery shows that feathers and scales were present simultaneously in early dinosaurs, and gives new support for the theory that feathers were widespread among all dinosaur clades.
Please see *doi:10.1126/science.1253351* for more information.
- Miniaturisation Was the Key to Survival For Dinosaur Descendants
Non-avian dinosaurs are today completely extinct. They were wiped out during the K-Pg extinction ~66 million years ago. However dinosaurs do still live among us today! Unlike their extinct predecessors, birds made it through the K-Pg boundary to become the most specious of all tetrapods alive today . So why were they able to survive, when the previously hugely successful non-avian dinosaurs didn’t make it through? It now appears that the avian bird lineage was the only branch of the dinosaur tree where dinosaurs continued to get smaller over 50 million years . An earlier 2014 study  also found that it was only in the dinosaur lineage leading to birds, that high rates of evolution were sustained for a long time, and therefore the lineage was able to repeatedly exploit new niches through time. Their small size may have allowed them to continue to radiate into new niches and this could have given birds the edge when life on Earth faced the most recent of its major mass extinctions [8,9].
Please see *doi:10.1126/science.1252243* and *doi:10.1371/journal.pbio.1001853* for more information.
- 59-tonnes and still growing; a gigantic titanosaur uncovered in Argentina
In September, a huge titanosaur dinosaur was discovered in south-western Patagonia, Argentina . The animal is from the Late Cretaceous, (-84-66ma), and has been named Dreadnoughtus schrani, after the battleships, because of its enormous size. This titanosaur is one of the most complete of the largest sauropodomorphs ever discovered, with up to 45.3% of bones, and 70.4% of the postcranial elements recovered (see image 10), allowing estimations of its body mass to be calculated. This individual has been estimated at a staggering 59.3 metric tonnes (see artists impression, image 11)! Although this is currently the largest estimation for any sauropodomorph, scientists can’t say for certain whether D.schrani is the largest due to the fragmented nature of other gigantic titanosaur remains. Moreover, experts think that this huge animal was still growing at the time of death. For me, this find is not only important as a candidate for the largest dinosaur, but because if it is, then it is also the largest animal ever to have walked the Earth. With such a high percentage of the postcranial bones preserved, Dreadnoughtus gives us a fantastic opportunity to investigate the biomechanics and anatomical structures involved in supporting such an incredibly massive terrestrial organism.
Please see *doi:10.1038/srep06196* for more information.
- Ichthyosaurs Missing Link?
Ichthyopterygians are marine reptiles that lived during the Mesozoic period. They are secondarily marine, meaning they evolved from a terrestrial ancestor, but sadly, as with so many of the important evolutionary links in the fossil record, there were no examples of any intermediate organisms. In November, however, a fossil was found in China that dated to ~248Ma  and appeared to be a basal ichthyosauriform (see image 12). The animal is much smaller than ichthyopterygians, and parts of its anatomy point toward an amphibious lifestyle, making it an excellent candidate for an intermediate organism between a terrestrial tetrapod group and ichthyopterygians. It has large flippers for its size, meaning it was likely able to support itself on land, moving around in a way similar to modern-day seals! Its short, wide snout and thickened ribs suggest that, unlike ichthyopterygians, it was probably a suction feeder. It’s always exciting to find intermediate species in the fossil record, and their discovery, although infrequent, can tell us huge amounts about the processes of evolution. This is especially true when these animals underwent a major transition like the one from terrestrial to marine, or vice versa, and therefore this discovery easily makes my top 10 breakthroughs of 2014.
Image 12: Fossil of amphibious basal ichthyosauriform. (Credit: reference )
Please see *doi:10.1038/nature13866*
for more information.
- Mammoth Autopsy
In November, what has to be my favourite palaeontology story of 2014 occurred. A permafrost mammoth found on Maly Lyakhovsky Island in northern Siberia was dissected by an international team of scientists, including Dr Tori Herridge from the London NHM. Carbon dating pinpoints the mammoths age to ~40,000Ma. The mammoth, found in May of 2013 and lovingly named ‘Buttercup’ (see image 13), was exceptionally well preserved, and presented mammoth experts with this exciting and incredibly rare opportunity. Although I cannot deny the excitement any palaeontologist gets from finding a beautifully preserved fossil, I assure you, you would not find any researcher in our field that would turn down the opportunity to have the unfossilised carcase of any extinct organism. Although this might sound goary, many more evolutionary questions can be answered when the complete biology of an animal is available as opposed to fossilised remains.
The team were able to dissect Buttercup over three days as her body thawed out (see image 14), and during the process deduced some interesting things about her life. Buttercups tusks revealed that she was a female, and that she had 8 calf’s. Pebbles were also found in her gut, around the size of a ping-pong ball, which, due to an abnormality with her teeth, were thought to have been used to grind up food and aid digestion. The scientists were even able to suggest a cause of death for Buttercup. They believe that she became stuck in a peat bog and died from predation.
Maybe the most astonishing thing to come from this mammoth autopsy however, is the presence of liquid blood (see image 15). Scientists managed to collect some of Buttercups blood as she thawed, and many believe that this is our first step toward mammoth cloning. The ethics behind this idea are, however, heavily debated, and I must admit it is not a venture that I personally support.
- Dating the Deccan Traps
For decades, there has been debate as to whether the formation of the Deccan Traps, a mountain range in India made up of layers of basalt from a massive outpouring of lava (see image 16), coincides with the K-Pg extinction, and with it the extinction of the dinosaurs. The Deccan Traps have long since been suggested as a possible contributing factor, or even cause, of the K-Pg mass extinction, but dating the flood basalts has proved difficult. For a long time the Deccan Traps were thought to have occurred before the extinction, and, although theories were put forward for a gradual decline of species prior to the K-Pg, the impact theory remained the most accepted one. In December however, a new paper appeared in science  proclaiming new dates for these huge lava outpourings. Using uranium-led (U-Pb) dating, the researchers obtained dates that suggested that the Deccan Traps were active just ~250,000 years before the Chicxulub impact, and that 80-90% of the ~123,000 cubic miles of lava was erupted within ~750,000, straddling the extinction event itself. If these dates are correct, they provide evidence that these flood basalts could have contributed to the extinction that wiped out all non-avian dinosaurs, along with many other creatures that were on Earth 66 million years ago. Flood basalts in different areas have also been suggested as possible causes of other major extinction events, for example the Siberian Traps and the End-Permian mass extinction . If it is in fact true that the Deccan Traps coincide with the K-Pg, then it shows that such an event can cause a large extinction, and gives reason for the other flood basalts around the globe to be re-dated.
Please see *doi:10.1126/science.aaa0118* for more information.
1. dos Reis, M., Donoghue, P.C.J., 7 Yang, Z., Neither phylogenomic nor palaeontological data support a Palaeogene origin of placental mammals. Biol. Lett. 10(20131003) (2014).
2. O’Leary, et al., The Placental Mammal Ancestor and the Post-K-Pg Radiation of Placentals. Science. 339(6120) 662-227 (2013).
3. Caron, J-B., Gaines, R.R., Aria, C., Mangano, M.G., & Streng, M., A new phllopod bed-like assemblage from the Burgess Shale of the Canadian Rockies. Nat. Com. 5(3210) (2014).
4. Conway Morris, S., & Caron, J-B., A primitive fish from the Cambrian of North America. Nature. 512, 419-422 (2014).
5. Penny, A.M., Wood, R., Curtis, A., Bowyer. F., Tostevin, R., & Hoffman, K-H., Ediacaran metazoan reefs from the Nama Group, Namibia. Science. 344(1504) 1504-1506 (2014).
6. Kaplan, M., Feathers were the exception rather than the rule for dinosaurs. Nature News. (2013) doi:10.1038/nature.2013.14379.
7. Godefroit, P., Sinitsa, S.M., Dhouailly, D., Bolotsky, Y.L., Sizov, A.V., McNamara, M.E., Benton, M.J., & Spagna, P., A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science. 345(6195) 451-455 (2014).
8. Benson, R.B.J., Campione, N.E., Carrano, M.T., Mannion, P.D., Sullivan, C., Upchurch, P., & Evans, D.C., Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage. PLoS Biol. 12(6) (2014).
9. Lee, M.S.Y., Cau, A., Naish, D., & Dyke, G.J., Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196) 562-566 (2014).
10. Lacovara, K.J., et al., A Gigantic, Exceptionally Complete Titanosaurian Sauropod Dinosaur from South Patagonia, Argentina. Scientific Reports. 4(6196) (2014).
11. Motani, R., Jiang, D-Y., Chen, G-B., Tintori, A., Rieppel, O., Ji, C., & Huang, J-D., A basal ichthyosauriform with a short snout from the Lower Triassic of China. Nature. (2014).
12. Schoene, B., Samperton, K.M., Eddy, M.P., Keller, G., Adatte, T., Bowring, S.A., Khadri, S.F.R., & Gertsch., B., U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction. Science. (2014).
13. Burgess, S.D., Bowring, S., & Shen, S-Z., High-precision timeline for Earth’s most severe extinction. PNAS. 111(9) 3316-3321 (2014).