Former research group member Olja Toljagic has just published her Master's research in the UK journal Biology Letters. This work focused on patterns of morphological diversity in the crocodilian stem-lineage (Pseudosuchia) across the Triassic–Jurassic mass extinction, which occurred 200 million years ago. Olja aimed to reevaluate previous work suggesting a major crash in pseudosuchian morphological diversity during this extinction. Her results suggested that morphological diversity of pseudosuchians during the Early Jurassic was similar to that of the Late Triassic (when corrected for sampling differences), and thus that the Triassic–Jurassic mass extinction was likely followed by a rapid ecological radiation of one major group of pseudosuchians, the crocodylomorphs.
There is quite a nice news story on this paper here.
Above: Estimated changes in pseudosuchian morphological diversity from the Late Triassic to Early Jurassic.
TOLJAGIC, O. & BUTLER, R. J. 2013. Triassic/Jurassic mass extinction as trigger for the Mesozoic radiation of crocodylomorphs. Biology Letters 9: 20130095.
We are now at the end of a very productive, and very busy
and tiring, first week in the Moscow collections. We’ve spent a lot of time
with material of several key taxa (Garjainia, Sarmatosuchus, Dorosuchus,
Eorasaurus, Archosaurus), collected a lot of data, and set-up some interesting
projects with our collaborators Dave Gower and Andrey Sennikov. Dave has now
returned to the Natural History Museum in London, but we (Martin, Roland and I)
are staying on for another week, and aiming to see as much additional material
as possible. Today we took a well-earned break, and Andrey and his wife took us
on a very enjoyable excursion to the Kremlin, Red Square, and St Basil’s Cathedral. We're enjoying some time off, but also looking forward to getting back into the collections come Monday.
Left: Dave Gower, Roland, Richard, Andrey Sennikov, and Martin outside the Paleontological Institute. Right: Roland, Martin and Richard in front of St Basil's Cathedral on Red Square.
We (Richard, Roland and Martin) are currently visiting the
Paleontological Institute (PIN) in Moscow. We’re visiting together with Dave Gower, and are being hosting by and working together with Andrey Sennikov, whom
it has been a pleasure to meet and discuss archosauromorph anatomy and taxonomy with. We’re here working on the fantastic collections of
Permian–Triassic archosauromorphs, which include numerous key species for
understanding the Triassic archosaur and archosauromorph radiations, such as
Archosaurus, Garjainia, Dorosuchus, Sarmatosuchus, Chalishevia and many others.
The amount of material here, much of it excellently preserved, is a bit overwhelming, but we're working frantically (11 hours in the collection today plus two hours commuting back and to the PIN...) to see as much of it as possible over the next couple of weeks.
Left: Richard (left), Roland (middle) and Martin (right), studying Garjainia and Dorosuchus material. Right: outside the entrance to PIN, with dinosaur-themed gates.
Back in 2011, at the Annual Meeting of the Society of Vertebrate Paleontology in Las Vegas, Phil Mannion, Roger Benson and myself organised a special symposium on patterns of vertebrate diversity (primarily species richness, but also morphological diversity, evenness and other metrics) in deep time, how differential sampling of the fossil record through time affects our ability to reconstruct those patterns, and how best to correct for sampling biases. This is currently a major area of debate in vertebrate palaeontology and palaeontology more broadly, and an exciting area to be working in. We had many excellent talks within the symposium, and now, some 18 months later, we have published a special volume of papers based on work presented in Las Vegas.
The special volume was recently published as a special issue of the journal Palaeo3 (Palaeogeography, Palaeoclimatology, Palaeoecology), and was edited by Phil, Roger and myself with help from David Bottjer. It includes 11 papers focusing on deep time diversity patterns in everything from fossil fish to mammals, with several papers focused on early vertebrate diversity and the Permian–Triassic extinction event. I am involved with two of the papers: a lead authored paper on pterosaur diversity patterns through time and their relationship with sampling, and a co-authored paper led by Roger Benson on tetrapod diversity patterns during the Cretaceous and relationships between regional and global metrics of sampling.
Above: cover of the special volume (left) and contents (right).
It's great to see this volume out finally, and thanks to all involved. I'm happy to send PDFs of any of the papers from the volume to anyone interested: just drop me an email.
Shockingly, we haven’t updated the news section of the
website properly since June last year, and a LOT has happened in the meantime. We’re now in the process of
revamping and updating the entire website, and it’s definitely time for an
update on what we’ve been doing.
In June–August Martin and Roland attended the five-week
training Intensive Workshop in Analytical Methods of the Paleobiology Database
in Sydney, Australia, where they gained skills in a range of quantitative approaches
to the study of the fossil record. Subsequently, they visited fossil
collections in Brisbane, Hobart (Tasmania), Adelaide, and Melbourne, examining
Triassic “proterosuchians” and a range of other Mesozoic vertebrates.
In July, Richard spent 10 days doing fieldwork together with Steve Brusatte, Grzegorz Niedzwiedzki, Piotr Szrek and (in Lithuania) Jonas Satkunas in the
Permian and Triassic of the Holy Cross Mountains in Poland and the Triassic of
Richard, Grzegorz and Piotr examining trace fossils at Starachowice Museum.
August saw Richard visiting Lourinha in Portugal to work with
Steve Brusatte and Octavio Mateus on Triassic vertebrate fossils collected in the
Algarve in previous years. Martin visited the University of Zurich in
Switzerland to work with Torsten Scheyer on histology of a new Upper Permian
archosauromorph species from Tanzania.
In September Richard attended the SVPCA conference in Oxford
in England and presented a talk on the Tanzanian Middle Triassic archosaur
Parringtonia. This work has subsequently been published as a joint-authored paper with Sterling Nesbitt.
Come October, come the Oktoberfest… After
we’d recovered from the festivities we hosted David Gower for several days for collaborative
research on a new erythrosuchid species from South Africa. Later that month we
flew to Raleigh, North Carolina, for the Annual Meeting of the Society of Vertebrate Paleontology. Richard presented work on phytosaurs from Bavaria,
Roland on early archosauromorph body size evolution, and Martin on early
theropod dinosaur phylogeny and evolution. Following the meeting, Martin and
Roland visited major fossil collections in Washington, Harvard, New York, and
Chicago, but both unfortunately got caught up in and in the aftermath of
Roland, Martin and Richard at the last night of SVP.
In December Roland and Richard attended the Annual Meeting
of the Palaeontological Association at University College Dublin,
Ireland. Roland presented a poster on early archosauromorph body size evolution,
while Richard talked about a new early ornithischian dinosaur from the
earliest Jurassic of Venezuela. Around the same time, Martin attended the 1st Annual Meeting of
Students of Paleontology held at the University of La Plata, Argentina. He gave a
talk on the new species of archosauromorph from the Permian of Tanzania and its
implications for the early evolutionary history of Archosauromorpha. The
manuscript describing this interesting new species is close to submission. Martin also visited fossil collections in Montevideo to examine new archosauromorph material from the Permian–Triassic of Uruguay.
Also in December Richard joined the Executive Committee of the Paleobiology Database, and in January was fortunate enough to fly to Berkeley
to participate in a strategic planning meeting discussing the future of the
Database. January was a busy generally month for the group: Roland visited the Natural History Museum in London
to carry out CT-scanning of Euparkeria specimens, and we hosted Roger Benson in Munich for collaborative work on body size evolution in Mesozoic vertebrates.
As part of this visit Richard and Roger visited collections in Stuttgart and Karlsruhe.
Finally, in February Richard visited Vienna for one week to
work on a new phytosaur species together with Eric Buffetaut. He also made a
flying visit to Berlin to CT scan a new species of basal rhynchosaur.
Phew! That's a very brief overview of activities of the last eight months - in forthcoming updates we'll talk about our recent papers, including two new special volumes of papers that we are involved in, as well as our forthcoming trip to Russia and other developments.
We have published several new papers in the last few weeks, and I haven't got around to updating the news section. Martin published two papers on dinosaurs: one focusing on the earliest dinosaur assemblages, and the other focusing on a new Cretaceous theropod dinosaur from Patagonia. I have been involved in three new papers: one documenting the results of our recent fieldwork in Lithuania, one redescribing the enigmatic early archosaur Parringtonia and implications for the archosaur radiation, and one focusing on the diversity of pterosaurs (flying reptiles) across the Mesozoic. There's lots more I could say about these, but no time right now...
Brusatte, S. L., BUTLER, R. J.,
Niedźwiedzki, G., Sulej, T., Bronowicz, R. & Satkunas, J.
(published online). First record of Mesozoic terrestrial vertebrates
phytosaurs (Diapsida: Archosauriformes) of probable Late Triassic age,
with a review of phytosaur biogeography. Geological Magazine. BUTLER, R. J.,
Benson, R. B. J. & Barrett, P. M. (published online). Pterosaur diversity:
untangling the influences of sampling biases, Lagerstätten, and genuine
biodiversity signals. Palaeogeography, Palaeoclimatology, Palaeoecology. EZCURRA, M. D.
2012. Comments on the taxonomic diversity and paleobiogeography of the
earliest known dinosaur assemblages (late Carnian-earliest Norian)
. Historia Natural, tercera serie 2: 49–71.
Nesbitt, S. J. & BUTLER, R. J. (published online). Redescription of the archosaur Parringtonia gracilis
from the Middle Triassic Manda Beds of Tanzania, and the antiquity of
Erpetosuchidae. Geological Magazine.
Novas, F. E., EZCURRA, M. D.,
Agnolín, F. L., Pol, D. & Ortíz, R. 2012. New Patagonian
Cretaceous theropod sheds light about the early radiation of
Coelurosauria. Revista del Museo Argentino de Ciencias Naturales, nueva serie, 14: 57–81.
Der Spiegel, Germany's leading weekly news magazine with a circulation of more than 1 million readers, recently carried an interview with me in their print edition, following up on our recent publication on dinosaur extinction in Nature Communications. The interview is in German, but for those who are interested, an image of the iPad version of the article is below.
We have recently returned from a long research trip in South Africa, visiting museums in Johannesburg, Pretoria, Cape Town, Bloemfontein and Grahamstown in order to study Triassic fossils of proterosuchids, erythrosuchids, Euparkeria, rhynchosaurs, Prolacerta, and early dinosaurs. We collected a vast amount of data, discussed some intriguing future fieldwork possibilities, and loaned some very interesting specimens for further study. We have a number of publications planned to result from this work, but it is already clear that we will need to make another visit to South Africa soon - the collections there are astonishingly rich!
Roland and Martin will both be flying to Sydney in Australia this week in order to join the Paleobiology Database Intensive Workshop in Analytical Methods, which will last until around the end of July. Afterwards they are going to check out the Triassic collections of proterosuchids and other archosauromorphs in Brisbane, Adelaide and Tasmania, as well as visiting a couple of other museum collections. In the meantime, I am gearing up for fieldwork in Lithuania and Poland, and a trip to Portugal to work on fossil material collected during fieldwork there in 2009–2011. Should be an exciting summer!
I am second author on a new paper published in Nature Communications on dinosaur morphological diversity in the lead-up to the end-Cretaceous extinction (in which all non-avian dinosaurs went extinct). The dinosaur extinction has generated a vast body of research and popular attention, but one of the most controversial questions has long been whether or not dinosaurs were already in a long-term decline of some sort before the asteroid impact and massive volcanism that mark the terminal Cretaceous boundary. Most previous work addressing this question has attempted to look at changes in species diversity through time, something that is very difficult to do accurately in the deep time fossil record. Together with lead author Steve Brusatte (American Museum of Natural History, New York), Albert Prieto-Márquez (BSPG, Munich) and Mark Norell (AMNH), we looked at the problem using a different approach: morphological diversity or disparity, the range of differences in skeletal anatomy shown by groups of dinosaurs through time. We found that some groups of large-bodied plant eaters were becoming less morphologically diverse, but that this was only true of the North American record, and not of the Asian dinosaur record. Other groups of dinosaurs do not appear to have been undergoing a decline in morphological diversity. Thus, changes in dinosaur biodiversity prior to their extinction appear to have been highly complex and differed according to clade and geographic region.
Disparity trends in four dinosaur groups during the final 12 million
years of the Cretaceous (North American species only). Time (from 77-65
million years ago) is shown on the x axis. The y axis shows the
disparity metric: sum of variances
derived from anatomical character databases. The error bars indicate
whether comparisons between time intervals are significant or not
(overlap of error bars means non-significance, no overlap means
significance). Overall, the large-bodied bulk-feeding ceratopsids
and hadrosauroids underwent a marked long-term decline, but the
carnivorous coelurosaurs and small herbivorous pachycephalosaurs were
stable. (AMNH/S. Brusatte)
The paper is available at the Nature Communications website or by sending me an email. There is coverage on the AMNH and LMU websites. The story has been covered by various blogs and news sources, including The New York Times, Live Science, Discovery News, Spiegel online, N24, the Guardian, Time, Stern and the Smithsonian Dinosaur Tracking blog.