Thalattosuchians

Thalattosuchians were a clade of marine crocodylomorphs that flourished from the Early Jurassic until the end of the Early Cretaceous.

 

One thalattosuchian branch, the teleosauroids, resembled modern gharials with some of them also evolving short-snouted turtle-cracking forms. The second branch, metriorhynchoids, instead evolved flippers and a tail fin, bearing more resemblance to other Mesozoic marine reptiles like ichthyosaurs and mosasaurs.

 

The Meereskrokodile project

Next to other countries like Argentina, France or the UK, Germany is one of the best places of the world to find well-articulated thalattosuchian fossils. The remnants derive mostly from Toarcian (e.g. Holzmaden, Dotternhausen, Mistelgau) and Kimmeridgian-to-Tithonian (Altmühltal, Wattendorf, Nusplingen) strata. But also other Jurassic and Cretaceous rocks of Germany bear several fossils of these marine reptiles.

 

To understand the German record of thalattosuchians better, me and my collaborators started the Meereskrokodile project (German for "marine crocodiles"). Our aim is to learn more about the taxonomy and  paleoecology of the German species and to enhance our general understanding of thalattosuchian paleobiology.

 

This is an independent project with Sven Sachs, Dr. Mark T. Young, Dr. Heinrich Mallison, Dr. Michela M. Johnson, Dr. Davide Foffa, Dr. Yanina Herrera, and Dr. James Kitson as collaborators.

 

Research highlights:

  • Two new species of the rhacheosaurin metriorhynchid Cricosaurus  from the Upper Jurassic of Bavaria (Sachs et al. 2019a, 2021). See more details here.
  • Redescription of the historically important teleosaurid Mystriosaurus (Sachs et al. 2019b). See more details here.
  • Introduction of the "E-clade", a new group of large geosaurine metriorhynchids (Abel et al. 2020). See more details here.

Holotype of the new species Cricosaurus bambergensis (Sachs et al. 2019) from the late Kimmeridgian of Wattendorf, Bavaria.

Life reconstruction of Mystriosaurus laurillardi with the early pterosaur Campylognathoides and the ammonite Dactylioceras during the early Toarcian of Altdorf bei Nürnberg, Bavaria. Artist: Julia Baier

Life reconstruction of an "E-clade" geosaurine ("Drügendorf Croc") in the early Kimmeridgian sponge reefs of the Franconian Jura, Bavaria. Artist: Joschua Knüppe.


Related publications:

  • Abel, P. (2021). Vor 1955: Macrospondylus bollensis – Puzzle eines Meereskrokodils. In: Aus der Tiefenzeit – Die Paläontologische Sammlung der Universität Tübingen (eds.: Seidl, E., Bierende, E. & Werneburg, I), Tübingen, 456–467.
  • Abel, P. & Pommery, Y. (2023). Fragmentary remains of a metriorhynchid crocodylomorph from the middle Oxfordian of France — the oldest known rhacheosaurin? 4th Palaeontological Virtual Congress. https://www.researchgate.net/publication/371005736_Fragmentary_remains_of_a_metriorhynchid_crocodylomorph_from_the_middle_Oxfordian_of_France_-_the_oldest_known_rhacheosaurin
  • Abel, P., Sachs, S., Young, M.T. (2018). Thalattosuchian remains from the late Aalenian Eisensandstein Formation of Baden-Württemberg, southwestern Germany. GeoBonn 2018 Living Earth Abstracts: p. 223.
  • Abel, P., Sachs, S., Young, M.T. (2020). Metriorhynchid crocodylomorphs from the lower Kimmeridgian of Southern Germany: evidence for a new large-bodied geosaurin lineage in Europe. Alcheringa: An Australasian Journal of Palaeontology 44 (2): 312–326. doi: 10.1080/03115518.2019.1701079
  • Abel, P., Sachs, S., and Young, M.T. (2021). Das Drügendorfer Krokodil: ein fränkischer Riese mit europaweiter Verwandtschaft. Fossilien – Erdgeschichte erleben 2021 (5), 24–39.
  • Sachs, S., Johnson, M.M., Young, M.T., and Abel, P. (2019). The mystery of Mystriosaurus: Redescribing the poorly known Early Jurassic teleosauroid thalattosuchians Mystriosaurus laurillardi and Steneosaurus brevior. Acta Palaeontologica Polonica 64 (3): 565–579. DOI: 10.4202/app.00557.2018
  • Sachs, S., Young, M.T., Abel, P., and Mallison, H. (2019). A new species of the metriorhynchid crocodylomorph Cricosaurus from the Upper Jurassic of southern Germany. Acta Palaeontologica Polonica 64 (2): 343–356. DOI: 10.4202/app.00541.2018
  • Sachs, S., Young, M.T., Abel, P., and Mallison, H. 2021. A new species of Cricosaurus (Thalattosuchia, Metriorhynchidae) based on a remarkably well-preserved skeleton from the Upper Jurassic of Germany. Palaeontologia Electronica: 24.2.a24: 1–28. doi: 10.26879/928
  • Young, M.T., Sachs, S. & Abel, P. (2018). Einblicke in die Evolution der Thalattosuchier - Meereskrokodile des Mesozoikums. Fossilien 3/2018: 16-23.
  • Young, M.T., Sachs, S., Abel, P., Foffa, D., Herrera, Y., Kitson , J.J.N. (2020). Convergent evolution and possible constraint in the posterodorsal retraction of the external nares in pelagic crocodylomorphs. Zoological Journal of the Linnean Society 189 (2): 494–520. doi: 10.1093/zoolinnean/zlaa021
  • Young, M.T., Wilberg, E.W., Johnson, M.M., Herrera, Y., de Andrade, M.B., Brignon, A., Sachs, S., Abel, P., Foffa, D., Fernández, M.S., Vignaud, P., Cowgill, T. and Brusatte, S.L. 2024. The history, systematics, and nomenclature of Thalattosuchia (Archosauria: Crocodylomorpha). Zoological Journal of the Linnean Society, zlad165. doi: 10.1093/zoolinnean/zlad165