Serjoscha Evers

Thanks Ashley. We were inspired by asking ourselves if some of our specimens for a GMM study are maybe to small/juvenile. The study has many limitations, but we are careful enough (I hope) so say this is a preliminary assessment based on available data that can (should) be taken a lot further

Thus, our recommendations: When doing macroevolutionary shape studies on turtles, mixed sex datasets are okay but specimens should be 65% max shell length for the species to ensure adult shape sampling. 🐢

Interestingly, our (preliminary) data suggest that sexual shape dimorphism in turtles is negligible when compared to ontogenetic change & interspecific differences even b/w closely related species.

Our main question: How big are turtles in terms of shell size (an oft available & easy to measure property) when ‘adult shape’ is reached. When we define adult shape as having reached 85% the shape difference b/w small juveniles & extremely large adults, the answer is at 65% max shell length

We then developed ontogenetic shell shape curves, analog to growth curves. Shell shape (measured w 2 methods) is plotted against shell size. These plots show generally that shell shape changes through growth, but shell shape change slows down to converge on an ‘adult shape’

Disparity between species is lower when only juveniles are considered, whereas intermediate sized & adult turtles have significantly increased disparity. This suggest that many lineage specific features of shell shape that cause this disparity appear only during postnatal ontogeny.

We took a large pre-existing turtle shell shape dataset fr Tristan Stayton’s work 🙏 We identified species specific datasets w large size variance to test for ontogenetic patterns - & they exist. Most turtles start w rounded shells as juveniles, possibly a developmental constraint related to swimming

PG-18: turtles reach adult shell shapes at about 65% maximum carapace length - Swiss Journal of Palaeontology Ontogenetic shell shape changes of turtles are often only documented for individual species. It is currently unclear how shell shape changes during ontogeny across species, if there are common trends,...

New paper by Guilherme Hermanson & me out: we explore ontogenetic shell shape change in turtles to check if there is a size threshold at which turtles reach adult shapes. This started for a different (in prep) study & was a fun little project w preliminary data

link.springer.com/article/10.1...

Snout of a Lias ichthyosaur with ammonites from the museum webpage.

If you are in Bayreuth, please stop by our museum - and if you are interested in collection visits, please reach out!

This is a permanent academic position in palaeontology - I am happy to have made it this far & am thankful to a great many people who helped me along the way 🙏

Some Muschelkalk fossils from the collection. Three skulls in various views.

With the museum team, my job will be to renew the exhibits, organize special exhibits, continue & expand excavations in Mistelgau, curate and organize collections, facilitate research & continue my own research. The job is very multifaceted, & I am excited for all parts of it!

View from the dinosaur garden towards the museum main building. A large sauropod sculpture stands in a backyard garden

I am happy to announce that as of this month, I am the new director of the Urwelt-Museum Oberfranken, with its >600m2 exhibit halls in the center of Bayreuth and a rich Triassic-Jurassic marine reptile collection from Muschelkalk deposits & Mistelgau alongside a rich Jurassic plant collection & more

Prof. Susannah Maidment JSP Editor-in-Chief

Welcome to our new co-Editor-in-Chief Prof. Susannah Maidment

Susannah is a renowned expert on the palaeobiology of bird-hipped ‘ornithischian’ dinosaurs at the Natural History Museum, London

🦕Read about her amazing work: buff.ly/4AfhohB

@tweetisaurus.bsky.social #Fossils #PaleoSky #Dinosaurs

Temnodontosaurus skeleton, close-up of the soft-tissue, and flipper illustration with 'chondroderms'

Big news! Our study, just out in Nature, is a game-changer for giant ichthyosaurs! We describe the first Temnodontosaurus flipper with fossilized soft tissue, giving us a unique look at how these massive creatures used stealth while hunting in darkness. 1/7
#science #news #scicomm

Figure from Paper showing skull anatomy based on 3D model from a CT scan in various views. Individual bones have different colours

The latest Turtle Evolution Symposium paper in our TES Special Volume: Rollot et al. describe a new species of carettochelyid turtle from the Miocene of Egypt, and name it Allaeochelys meylani, after Peter Meylan, who published a lot of trionychian research.

sjpp.springeropen.com/articles/10....

The lagerpetid Scleromochlus, one of the closest relatives of pterosaurs. Artowrk by Gabriel Ugueto

‪[1/n] New paper co-lead by @emmadnn.bsky.social‬ @macroecoevoale.bsky.social‬ and I: we combined fossil occurrences, biogeography and climate modelling to investigate the origins and early evolution of pterosaurs 🔗 www.nature.com/articles/s41...

Previously known partial fossil published in Nature. Unsurprisingly, the fossil is not a turtle.

Portrait of myself, smiling with my habilitation document in hand in front of a tree

Today, I submitted my habilitation at the Uni of Fribourg! I taught more than 100 hours of palaeontology & historical geology over the last years - happy to finally have gotten all requirements together…

Overcoming polymorphism: a revised list of shell characters for the phylogenetic analysis of soft-shelled turtles (Pan-Trionychidae) - Swiss Journal of Palaeontology Soft-shelled turtles (Pan-Trionychidae) are one of the primary clades of turtles with a particularly rich fossil record reaching back to the Early Cretaceous. Yet, the evolution of the group has been ...

And the next article published in our conference special volume is by Walter Joyce, on trionychid (softshell) turtle phylogeny with a special focus on how to deal with polymorphisms in character state observations:

sjpp.springeropen.com/articles/10....

Turtles are way (like waaay) cooler than (most) palaeos give them credit for, & we need new minds in the community - so consider applying even if turtles were not yet your thing during your previous education! Amazing datasets are already in place & Tübingen is one of the prettiest places in Germany

Nearly missed #WorldTurtleDay2025… Today I got invited to a cool turtle dig, received a turtle paper draft for comments, WhatsApped turtle pics w a colleague, made 15 turtle figs for a huge phylo MS & scheduled turtle meetings for next week. Let’s face it: everyday is turtle day (-weekends). 🐢❤️

Introducing Asmodochelys leviathan, a new giant marine turtle from the Maastrichtian of Texas!
sjpp.springeropen.com/articles/10....
This new 72-million-year-old species was one of the sole survivors of an extinct lineage that patrolled the gulf coast of North America near the end of the Cretaceous

figure of shell material of the new sea turtle as provided in the article by Smith et al.

@heatherfsmith.bsky.social and colleagues published on a new Maastrichtian ctenochelyid sea turtle, Asmodochelys leviathan.

link.springer.com/article/10.1...

Flying turtles in the earliest trees of life: scientific transparency in the phylogenetic works of Ernst Haeckel - Swiss Journal of Palaeontology The evolutionary origin of turtles has long been debated, and recent studies continue to provide conflicting results. In some of the first trees of organisms ever drafted, Ernst Haeckel (1834–1919) pl...

The first published article is by Werneburg & Hoßfeld, and is a bit of a historical account of Haeckel's phylogenetic work.

link.springer.com/article/10.1...

Special Volumes were published w previous TES meetings & we believe that this actually motivates people to finish their projects not too long after the meeting. We had vouchers for all people who cannot stem open access fees – so hopefully this open collection of research will benefit the community

Following up fr our 2024 Turtle Evolution Symposium in Fribourg (🇨🇭), Walter Joyce, Yann Rollot & I are guest-editing a collection in the Swiss Journal of Palaeontology. As the 1st papers are coming out, I'm starting this thread to update you all on turtle science.

link.springer.com/collections/...

For the 1st time in years, I submitted an abstract to SVP! I reduced conference attendance a lot over the last years, but I cannot let a European SVP conference 'close' by slip... Now fingers crossed for an acceptance. Looking forward to see @richardjbutler.bsky.social et al. host #2025SVP #SVP2025

The postcranial anatomy and osteohistology of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha) from the Late Triassic of Wales The earliest crocodylomorphs, known as non-crocodyliform crocodylomorphs, first appeared during the Late Triassic. In contrast to extant crocodylians, which are all semi-aquatic, early crocodylomorph...

Well done to our Edward Forbes Prize winner, @stephanspiekman.bsky.social for his paper on ‘The postcranial anatomy and osteohistology of Terrestrisuchus gracilis (Archosauria, Crocodylomorpha) from the Late Triassic of Wales.’ onlinelibrary.wiley.com/doi/10.1002/...

If you are interested in biodiversity in deep time, check out my new preprint with @rachelwarnock.bsky.social and @dralexdunhill.bsky.social! We review methods of quantifying diversity and diversification, using the fossil record and phylogenies with extinct tips 🐚🦕📊
doi.org/10.32942/X2D...

Social media postcard that says: Are you an early-career researcher within five years of your first appointment to a faculty position? You could be eligible for our new grants for junior faculty staff The Journal of Experimental Biology logo is in the bottom left corner. The Kickstart grant logo, two hands shaking, is in the bottom right corner.

If you're a new PI within 5 years of your first faculty position, here are two fantastic grants to help develop your research: the Kickstart Travel Grant and ECR Visiting Fellowships Find out more at biologists.com/grants/#jeb The next application deadline is 6 June

Please repost

Our new preprint on apparent evolutionary rate incongruences in squamates for discrete vs GMM data across distinct methods, and what these patterns may reflect of their underlying phenotypic evolutionary processes: ecoevorxiv.org/repository/v...
#evolution #squamates