Field trip to the Otways

Another post, another field trip! I’ve been quite fortunate so far this year, this trip was my third already and it’s only March (I think my fiancé has forgotten who I am)! In my defence though, this trip was only a short two night stay, with a day and a half worth of field work.

But enough already, where did I go? The locality we were digging at is known as Eric the Red West and it is situated on the southern coast of Victoria’s Otways ranges, around four hours west of Melbourne. The name of the site comes from a famous ship known as Eric the Red that wrecked there in 1880, whose anchor lies just east of our dig site, hence the Eric the Red West! The rocks at this locality are similar to those found at the site of my last field trip at Flat Rocks, Inverloch, which is on the other side of Melbourne. However the rocks in the Otways, although also Early Cretaceous, are around 10 million years younger than those found at Inverloch. They would have once been part of the same single unit but geological events in the Miocene have split them into two separate groups. The fossils found from the Otways are from the Eumarella Formation, Otways Group and the Flat Rocks fossils are from the Wonthaggi Formation, Strzelecki Group (Benson et al., 2012). This temporal difference between the two areas gives us a unique opportunity to study the evolution of life here in Victoria during the early Cretaceous as we can compare the two sites and look for differences in the flora and fauna.

Map showing not only the Eric the Red West site and the Flat Rocks site at Inverloch, but other fossil localites from Victoria. Image from Benson et al., 2012.
Map showing not only the Eric the Red West site and the Flat Rocks site at Inverloch, but other fossil localities from Victoria. Image from Benson et al., 2012.

Another bonus of a field trip to the Otways is the camp we get to stay in. Called Bimbi Park, it is situated right in the middle of the Otways Ranges National Park (so no Internet, hence the lateness of this blog post) where you are surrounded by trees full of Koalas, although at night when you’re trying to sleep and the males won’t stop bellowing they can lose their appeal momentarily! It really is a beautiful picturesque spot for getting away from it all and I’d definitely recommend it should you ever find yourself in that neck of the woods.

Picture of the campsite at Bimbi park. You really do get to sleep with Koalas above your head! Image from planbooktravel.com
Picture of the campsite at Bimbi park. You really do get to sleep with Koalas above your head! Image from planbooktravel.com

Tourism plugs aside, there have been several notable finds at the Eric the Red West site since it was first prospected in 2005 (Kool, 2010). There tends to be fewer finds at the Otways site, but the material is often of better quality than Flat Rocks. One of the best came on that very first day of prospecting when an articulated tail and complete right foot of a small ornithopod dinosaur was discovered. In 2006 Inverloch and Otways dig stalwart Mary Walters found a mammal jaw (not her first one either) and more recently, dig regular Alanna Maguire has found the first upper mammal jaw from the Cretaceous of Australia (something that is still being researched at present).

The mammal jaw Mary Walters found at the Eric the Red West site in 2006, prompting an annual field season there every year since. Image from the 2007 Dinosaur Dreaming Field Report.
The mammal jaw Mary Walters found at the Eric the Red West site in 2006, prompting an annual field season there every year since onwards. Image from the 2007 Dinosaur Dreaming Field Report.

This field season is proving to be a very profitable one with the record for number of bones found in one day at the site being broken on the Monday I was there, and just prior to writing this post I read (via the Dinosaur Dreaming blog) that they had found two ornithopod jaws! There are some very exciting fossil layers being chased into the rock at present and hopefully they keep finding more cool stuff!

Now, where should I go for my next field trip…?

References

Benson, RBJ, Rich, TH, Vickers-Rich, P, Hall, M (2012) Theropod Fauna from Southern Australia Indicates High Polar Diversity and Climate-Driven Dinosaur Provinciality. PLOS One 7(5): e37122. doi:10.1371/journal.pone.0037122.

Kool, L (2010) Dinosaur Dreaming. Exploring the Bass Coast of Victoria. New Artworx, Melbourne. 95pp.

Field trip to Flat Rocks, Inverloch

For the past week I’ve been at a dinosaur dig I’ve been fortunate enough to attend every February since 2010. The dig, jointly organised by Monash University and Museum Victoria, is known as Dinosaur Dreaming and has been running every summer for the past 20 years, making it potentially the longest running dinosaur dig in the world!

The Dinosaur Dreaming site is approx. 113 km SE of Melbourne and has yielded numerous fossils for the past two decades. Image from Google maps.
The Dinosaur Dreaming site is approx. 113 km SE of Melbourne and has yielded numerous fossils for the past two decades. Image from Google Earth.

The locality is dated as Aptian (Early Cretaceous, ~120 Ma) and represents a a floodplain that existed in the rift valley formed by the gradual separation of Antarctica and Australia, a process that wasn’t completed until over 80 million years later. The supercontinent that these two continents formed part of (along with South America, Africa and India) was known as Gondwana. The fossils are found in layers in the light grey sandstone and conglomerate, along with abundant coal, fossilised tree stumps and other plant material. It is believed that the fossil material would have been swept in from locations upriver during episodes of flooding that caused the main rivers nearby to burst their banks. These fossil layers are what we look for when we dig at this site. It usually means having to clear off a sizeable amount of sand each morning to reaccess the fossil layer! Once we’ve cleared off the overburden a few crew members then use sledgehammers to break large chunks of rock out of the ground which is then passed to other crew members who break it down into sugar cube sized pieces searching for the fossils within.

Yours truly examining a rock to see if there any fossils inside. I almost look like I know what I'm doing! Image by Darren Hastie.
Yours truly examining a rock to see if there any fossils inside. I almost look like I know what I’m doing! Image by Darren Hastie.

And what type of fossils are we looking for exactly? Well, so far finds have included: dinosaurs (ornithopod and theropod), mammals, turtles, freshwater plesiosaurs, pterosaurs and fish, giving us a reasonably good idea of what made up this Early Cretaceous ecosystem. The downside is however that, as the material has been swept in by flooding, it is very rarely that complete elements are found (although keep your eyes peeled at the end of 2013/start of 2014 for something truly amazing coming from the site…). It is much more common to find small fragments of fossils that researchers then have to use all of their experience to piece the animal back together again, both literally and figuratively!

Another plus about the dig is that it provides school children from right across the state the chance to come and see what a real life dinosaur dig looks like (I wish I had that when I was a kid), they even get the chance to have a look for some fossils themselves!

The dig has its very own blog too, which keeps the public up to date with the goings on of the dig and what the diggers get up to during the rest of the year. Check out this video on the dinosaur dreaming blog, which shows the dig site and what we do, it even includes a short appearance by yours truly right at the end!

A massive thank you must go to Lesley, Gerry, Dave, Wendy, John and Lisa for all their hard work in keeping the dig going for as long as they have, hopefully it can last another 20 years!

 

The Lark Quarry Trackway: Thulborn Strikes Back

UPDATE: I made a slight mix up when writing this article last week. I have stated that Thulborn, 2013 is responding to the claims of Romilio et al. 2012. This is actually incorrect. The paper to which Thulborn is responding is Romilio and Salisbury, 2011, where they dispute the identity of the large track maker at Lark Quarry and its consequences for the interpretation of the trackway. Thulborn has not yet responded to the new claims in Romilio et al. 2013, although he may do so in future. The core message of the article however is still the same. Romilio et al. do not believe that the trackway at Lark Quarry represents a dinosaur stampede, whereas Thulborn maintains it does. This intriguing topic will no doubt continue to provide ample material for debate in the years to come. This article has been edited from its original and second versions. For anyone who wants to see the original version, email me at the address at the top of the blog.

Regular readers of this blog (if there is such a thing) may recall that I wrote an article about a new paper by Romilio & Salisbury where they disputed the claims made by Tony Thulborn, who stated that the dinosaur trackways at Lark Quarry, Queensland were made by stampeding dinosaurs. In their paper they proposed that in fact the trackways were made at different times and showed dinosaurs crossing a river.

Perhaps a stampede after all? Thulborn certainly still seems to think so. Image from abc.net.au.
Perhaps a stampede after all? Thulborn certainly still seems to think so. Image from abc.net.au.

Now, Thulborn has responded to the claims made by Romilio & Salisbury, 2011, rejecting their analysis. In his rebuttal, Thulborn criticises their application of the multivariate analysis method, pointing out that they didn’t actually compare trackways of ornithopods and theropods but rather studied a single trackway, meaning that the only variation they could obtain would be between the individual tracks themselves. He also states that the multivariate analysis “appears to be based on fabricated data and is, therefore, worthless”.  The outlines of these tracks would have also deteriorated over time (Thulborn and Wade, 1984).

Thulborn also takes issue with how Romilio et al. have portrayed Thulborn’s initial interpretation of the site as a prey-pursuit scenario. Thulborn makes the distinction that he has never said it was this particular scenario (except when explicitly speculating), but rather that it was merely a stampede in general, regardless of the identity of the large track maker. Indeed, he argues that the whole premise of the recent paper by Romilio et al. seems to be to declare the larger tracks were in fact made by a large ornithopod, a fact that Thulborn declares is a “separate matter of secondary interest”.

So is the trackway at Lark Quarry evidence of a dinosaur stampede or not? Well, it depends on who you ask at the moment! Further study will no doubt show which of the two parties were closest to being correct. This debate is sure to continue; I’ll keep you all updated when the next developments arise!

References

Romilio A, S. W. Salisbury (2011) A reassessment of large theropod dinosaur tracks from the mid-Cretaceous (late
Albian-Cenomanian) Winton Formation of Lark Quarry, central-western
Queensland, Australia: A case for mistaken identity. Cretaceous research 32: 135-142.

Romilio A, Tucker, R. T. and S. W. Salisbury (2013): Reevaluation of the Lark Quarry dinosaur Tracksite (late Albian–Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede?, Journal of Vertebrate Paleontology, 33:1, 102-120.

Thulborn, R.A. (2013): Lark Quarry revisited: a critique of methods used to identify a large
dinosaurian track-maker in the Winton Formation (Albian–Cenomanian), western Queensland, Australia, Alcheringa: An
Australasian Journal of Palaeontology, DOI:10.1080/03115518.2013.748482

Thulborn, R. A., and M. Wade. 1984. Dinosaur trackways in the Winton
Formation (mid-Cretaceous) of Queensland. Memoirs Queensland
Museum 21:413–517.

The Dromornithids: An Introduction

Australia has been separated from the rest of the world for the majority of the last 65 million years, with complete separation occurring around 30 million years ago. This has given the various forms of life on the continent plenty of time to evolve into their own unique groups. One particularly fascinating and enigmatic group is the family of extinct, giant flightless birds known as the dromornithids.

A reconstruction of Dromornis stirtoni by the fantastic palaeo-artist Peter Trusler. In this image they have been reconstructed as herbivores.
A reconstruction of Dromornis stirtoni by the fantastic palaeo-artist Peter Trusler. In this image they have been reconstructed as herbivores.

Australia today is famous for a group of flightless birds known as the emus; and for a long time the dromornithids were believed to be members of the same group of birds (the ratites). However, in 1998 a study by Murray and Megirian demonstrated that dromornithids are in fact neognathous birds in the Anseriformes. Nonetheless, it remains debatable as to which anseriform group is sister to the dromornithids (Murray & Vickers-Rich 2004, Olson 2005, Agnolin 2007). With a fossil record spanning around 25 million years, dromornithids are known from the late Oligocene through to the late Pleistocene (Field & Boles 1998, Nguyen et al. 2010). An ancient origin for the group is implied by a possible dromornithid foot impression from the early Eocene (approx. 50 million years ago) of Queensland (Vickers-Rich and Molnar 1996). Following an overdue taxonomic revision of the Dromornithidae (Nguyen et al. 2010), the family includes seven accepted species in four genera, with a geographic distribution including every state in Australia. The largest species, Dromornis stirtoni, is estimated to have stood at 3 m tall and weighed up to 500 kg, potentially even larger than the famous elephant bird of Madagascar.

A skeletal reconstruction of Dromornis stirtoni with human for scale showing just how big these animals could have been. Image from www.carnivoraforum.com.
A skeletal reconstruction of Dromornis stirtoni with human for scale showing just how big these animals could have been. Image from http://www.carnivoraforum.com.

There has been some debate as to whether the dromornithids were herbivorous or carnivorous, with features of the skull hinting at the potential for either way of life. Skull material is not known from every species however, and all members of the group may not have shared the same feeding ecology. Gizzard stones have been found in association with dromornithid remains, suggesting they needed the stones to help process plant material, although carnivores such as crocodiles are also known to possess them.

The dromornithids went extinct in the late Pleistocene and it is still unclear what combination of human hunting, landscape changing or climate change was the ultimate cause of their demise.

This is another Peter Trusler reconstruction, this time of the late Pleistocene species Genyornis newtoni. This species could well have encountered the first humans to arrive in Australia, but were they the cause of their extinction?
This is another Peter Trusler reconstruction, this time of the late Pleistocene species Genyornis newtoni. This species could well have encountered the first humans to arrive in Australia, but were they the cause of their extinction? Image from Museum Victoria.

I have also had a personal interest in the dromornithids as myself and Dr. Erich Fitzgerald published a short paper on the Dromornithids last year (Park and Fitzgerald, 2012). In it we detailed the oldest known occurrence of the dromornithids in Victoria, a poorly preserved partial tarsometatarsus (one of the bones in the legs of birds). This bone appeared to represent a new species as it could not be referred to any of the known taxa elsewhere in Australia. Previously, the earliest known dromornithids in Victoria were from the late Pleistocene ( approx. 30,000 years ago) Lancefield Swamp locality, so this find pushes their presence in Victoria back in time considerably. It also cautions against deriving evolutionary patterns solely on the basis of fossils from northern Australia.

The dromornithids as a group still retain a lot of mystery and unanswered questions, and are long overdue for a thorough reanalysis. In fact, one of my colleagues plans to do exactly that over the next few years and I for one look forward to seeing what new details he can reveal about these ‘magnificent Mihirungs’.

References

AGNOLIN, F.L., 2007. Brontornis burmeisteri Moreno & Mercerat, un Anseriformes (Aves) gigante del Mioceno medio de
Patagonia, Argentina. Revista del Museo Argentino de Ciencias Naturales 9, 15–25.

FIELD, J.H. & BOLES, W.E., 1998. Genyornis newtoni and Dromaius novaehollandiae at 30,000 b.p. in central northern New South Wales. Alcheringa 22, 177–188.

MURRAY, P.F. & MEGIRIAN, D., 1998. The skull of dromornithid birds: anatomical evidence for their relationship to Anseriformes. Records of the South Australian Museum 31, 51–97.

MURRAY, P.F. & VICKERS-RICH, P., 2004. Magnificent Mihirungs: the Colossal Flightless Birds of the Australian Dreamtime. Indiana University Press, Bloomington, 410 pp.

NGUYEN, J.M.T., BOLES, W.E. & HAND, S.J., 2010. New material of Barawertornis tedfordi, a dromornithid bird from the Oligo- Miocene of Australia, and its phylogenetic implications. Records of the Australian Museum 62, 45–60.

OLSON, S.L., 2005. Review of Magnificent Mihirungs: the Colossal Flightless Birds of the Australian Dreamtime. The Auk 122, 367–371.

Travis Park & Erich M. G. Fitzgerald (2012): A late Miocene–early Pliocene Mihirung bird (Aves: Dromornithidae) from Victoria, southeast Australia, Alcheringa: An Australasian Journal of Palaeontology, 36:3, 419-422.

VICKERS-RICH, P. & MOLNAR, R.E., 1996. The foot of a bird from the Eocene Redbank Plains Formation of Queensland, Australia. Alcheringa 20, 21–29.

Why did the dinosaur cross the river? Because it wasn’t a stampede.

One of Australia’s best known dinosaur sites, the Dinosaur Stampede National Monument at Lark Quarry, near Winton, Queensland has just been dramatically reinterpreted in a new paper published in the Journal of Vertebrate Paleontology.  The site, which was covered by a purpose built building in 2002 and placed on the Australian National Heritage List in 2004 preserves over 3000 individual tracks that, until recently, were believed to demonstrate evidence of a ‘jumanji-esque’ dinosaur stampede.

Where these tracks made by fleeing dinosaurs of were they trying to cross a river? Image from environment.gov.au
Were these tracks made by fleeing dinosaurs or were they trying to cross a river? Image from environment.gov.au

The new paper, by Anthony Romilio (University of Queensland), Ryan Tucker (James Cook University) and Steven Salisbury (University of Queensland) puts forward a rather different hypothesis: the tracks represent a river of varying depth that dinosaurs often had to cross.

The orthodox spin on the story identifies two ichnotaxa (taxa known only from their tracks) as the track makers. Wintonopus, a small ornithopod and Skartopus, a small theropod. This was actually used as evidence of ‘mixed herding’ where small herbivores and carnivores hung around together as protection against larger predators Thulborn and Wade (1979, 1984, 1989).

Romilio et al. disagree with this interpretation. they claim that there is in fact only a single track maker present, which would be named as Wintonopus as it was named first, with Skartopus becoming a junior synonym. They also failed to find any evidence of a single mass of running individuals leaving them with their own opinion on what was going on here. “The presence of swim traces, long stride lengths, and preferred trackway orientation indicates that the majority of Lark Quarry trackmakers moved downstream and were current assisted. The paleo-water depth would have had to vary in order to allow different-sized buoyed trackmakers to contact the substrate, indicating that animals passed through the area at different time intervals. In the absence of evidence for the single mass of running terrestrial trackmakers, we consider that Lark Quarry is not representative of a ‘dinosaurian stampede.'”

A more accurate picture? Image by Anthony Romilio.
A more accurate picture? Image by Anthony Romilio.

So, which view is more accurate? Only time, and further research will tell. But as there appears to be some friction between the authors of the new paper and Richard Thulborn (one of the authors of most of the earlier work on the trackways), one thing is for sure; this isn’t the last we’ve heard about the Lark Quarry trackway.

The paper is discussed in a little more detail by Brian Switek (@Laelaps) on his excellent blog Laelaps (one of the best palaeo blogs going).

References

Romilio A, Tucker, R. T. and S. W. Salisbury (2013): Reevaluation of the Lark Quarry dinosaur Tracksite (late Albian–Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede?, Journal of Vertebrate Paleontology, 33:1, 102-120

Thulborn, R. A., and M. Wade. 1979. Dinosaur stampede in the Cretaceous of Queensland. Lethaia 12:275–279.

Thulborn, R. A., and M. Wade. 1984. Dinosaur trackways in the Winton
Formation (mid-Cretaceous) of Queensland. Memoirs Queensland
Museum 21:413–517.

Thulborn, R. A., and M. Wade. 1989. A footprint as a history of movement; pp. 51–56 in D. D. Gillette andM.G. Lockley (eds.),Dinosaur Tracks and Traces. Cambridge University Press, Cambridge, U.K.

Australian fossil penguins – the story so far…

Everybody loves penguins. From Happy Feet to the plethora of nature documentaries on the breeding cycle of the Emperor penguin, who can resist that awkward shuffle on land and the effortless grace in water? One facet of the penguin story that most people won’t be as familiar with is penguin palaeontology. This field has seen a renaissance since the early 1990’s with New Zealand and South America and Antarctica leading the way and South Africa also having their fair share of attention. One region that has been left out of this flurry of penguin research is Australia.

The published fossil record of penguins in Australia, although limited compared to that of Antarctica, New Zealand and South America, spans some 40 million years from the late Eocene to Recent (Ksepka and Ando, 2011). The majority of previous work has been produced by one author, none other than George Gaylord Simpson (Simpson, 1957, 1959, 1965, 1970), with the first publication released in 1938 (Finlayson, 1938) and the last primary research conducted by Van Tets and O’Connor (1983) a 30 year lull! A total of ten different localities are known from South Australia and Victoria (Park and Fitzgerald, 2012). In addition to numerous unidentifiable fragments, a total of five species have been named from the Australian material: Pachydyptes simpsoni (Eocene); Anthropodyptes gilli (Miocene); Pseudaptenodytes macraei (Miocene); Pseudaptenodytes minor (Miocene) and Tasidyptes hunteri (Holocene). Only two of these (A. gilli and P. macraei) are at present considered taxonomically distinct and only one species (P. simpsoni) is known from associated remains. All other species are based on individual and/or partial specimens, with the majority of specimens being too fragmentary for identification below the family level.

Holotype of Pachydyptes simpsoni. Unfortunately this is the most complete fossil penguin yet found in Australia, perhaps a reason for the lack of research! From Park & Fitzgerald, 2012. Photo taken E. M. G. Fitzgerald.
Holotype of Pachydyptes simpsoni. Unfortunately this is the most complete fossil penguin yet found in Australia, perhaps a reason for the lack of research! From Park & Fitzgerald, 2012. Photo taken by E. M. G. Fitzgerald.

A new paper co-authored by myself and Dr. Erich Fitzgerald (senior curator of vertebrate palaeontology at Museum Victoria) reviews the fossil record of penguins in Australia. Whilst the record is undoubtedly fragmentary, material is known from every epoch since the Eocene and virtually every find up until now has been by chance. So the potential is there for new discoveries to be made, should actually someone go and specifically look for fossil penguins. Furthermore, material has continued to accumulate in museum collections over the past 30 years despite the lack of research, some of it worthy of further study (keep your eyes peeled later in the year for that). So consider this an unfinished story, the fossil penguins of Australia have a few more tales to tell.

Link to the paper: http://museumvictoria.com.au/pages/41623/momv-2012-vol-69-pp309-325.pdf

References

Finlayson, H. H. 1938. On the occurrence of a fossil penguin in Miocene beds in South Australia. Transactions of the Royal Society of South Australia 62:14–17.

Ksepka, D. T., and T. Ando. 2011. Penguins Past, Present, and Future: Trends in the Evolution of the Sphenisciformes; pp. 155–186 in G. Dyke, and G. Kaiser (eds.), Living Dinosaurs. The Evolutionary History of Modern Birds. Wiley-Blackwell, West Sussex.

Park, T., and E. M. G. Fitzgerald. 2012. A review of Australian fossil penguins (Aves: Sphenisciformes). Memoirs of Museum Victoria 69: 309–325

Simpson, G. G. 1957. Australian fossil penguins, with remarks on penguin evolution and distribution. Records of the South Australian Museum 13:51–70.

Simpson, G. G. 1959. A new fossil penguin from Australia. Proceedings of the Royal Society of Victoria 71:113–119.

Simpson, G. G. 1965. New record of a fossil penguin in Australia. Proceedings of the Royal Society of Victoria 79:91–93.

Simpson, G. G. 1970. Miocene penguins from Victoria, Australia, Chubut, Argentina. Memoirs of the National Museum, Victoria 31:17–24.

Van Tets, G. F., and S. O’Connor. 1983. The Hunter Island penguin, an extinct new genus and species from a Tasmanian midden. Records of the Queen Victoria Museum 81:1–13.