Remains of the first Eurasian sebecid finally recovered and published.

The outlook on specializations acquired by crocodyliforms is broadened further with the recent study revolving around Ogresuchus furatus. 

Crocodyliforms remain one of my favorite clade of archosaurs, given they exhibit remarkable evolutionary traits and specializations.

And this particularly interesting case suggests a hatchling specialist predator.

• The study also raises questions challenging the assignment of origin dates for the group, along with the presumed dispersal and radiation of sebecid crocodylomorphs.
• This also points towards a possibility of potential convergent evolution between linages that were geographically isolated.

The holotype is under the label MCD-7149 and appears to be a semi-articulate skeleton preserving the anterior part of the rostrum and several axial and appendicular elements, and titanosaurian eggshell fragments.

Moreover, as cited by the papers, taphonomic evidences suggest that Ogresuchus' corpse after death remained in the same site during the ingress of fossilization.

Said site being a titanosaurian mass nesting zone.

Quite an exciting bit of information, and under it's impression, you and I would probably assume that this animal occupied a niché of an opportunistic egg-stealer. Similar to that of the modern day Monitor lizard or tegu, predators that lurk around nesting grounds, waiting to devour unhatched eggs the instant presented with an opportunity to do so.

However, the study states that the small body size of Ogresuchus and its dental morphology suggest some basic biometric and biomechanical limitations for directly predating upon a 19–23 cm-in-diameter thick shelled egg.

• The small cranial size of Ogresuchus probably could not load an efficient bite force upon the thick megaloolithid eggshell.

Which makes sense since the eggs belong to titanosaurian sauropods, and massive dinosaurs would obviously birth equally massive eggs.

• In addition, none of the 30 eggshells surrounding the skeleton nor any of the 1,000 fragments discovered at the site bore any evidence of the characteristic tooth-hole marks and cracking associated to predation of unhatched eggs.

Adding to this, one of the most highlighting features of Ogresuchus is its labio-lingual compressed dentition without serration and marked apicobasal ridges on the tooth crown, a dental condition shared with some theropod dinosaurs like Buitretraptor and Compsognathus.

Image highlighting Ogresuchus dentition

• The blade-like morphology of caniniform teeth of Ogresuchus could ideally perforate the soft and uncalloused flesh of a titanosaur hatchling with relative ease.

Needless to say, the discovery of this crocodyliform paired with it's blunt morphological features strongly point towards it's infanticidal habits.

Boom! We have a specialist hatchling killer, that quite possibly fed exclusively on hatchlings.

Find the complete study here:

https://www.researchgate.net/publication/344317134_A_small_Cretaceous_crocodyliform_in_a_dinosaur_nesting_ground_and_the_origin_of_sebecids

https://novataxa.blogspot.com/2020/09/ogresuchus.html?m=1