Magyarosuchus

Not to be confused with the dinosaur Magyarosaurus.

Magyarosuchus is an extinct monotypic genus of metriorhynchoid thalattosuchian described for the first time from fossils discovered in the Kisgerecse Marl Formation in Hungary. The type species Magyarosuchus fitosi lived during the Toarcian, about 180 million years ago.^[1] Most of the skeleton is known, including parts of the jaw, torso, legs and tail, which was discovered in 1996. It was around 4.67–4.83 metres (15.3–15.8 ft) long when fully grown.^[1]

Magyarosuchus Temporal range: Early Jurassic, Toarcian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauria
Clade:	Pseudosuchia
Clade:	Crocodylomorpha
Suborder:	†Thalattosuchia
Superfamily:	†Metriorhynchoidea
Genus:	†Magyarosuchus Ősi et al., 2018
Species:	†M. fitosi
Binomial name
†Magyarosuchus fitosi Ősi et al., 2018

Evolution & Classification

Magyarosuchus is an early member of the clade Metriorhynchoidea.^[1] These were the most marine-adapted group of thalattosuchians, with the later and more derived family Metriorhynchidae being fully marine, dolphin-like predators.^[2] Magyarosuchus exhibited a mosaic of adaptations for offshore life alongside ancestral, non-marine traits. For instance, it retained body armor similar to that of earlier thalattosuchians and terrestrial crocodylomorphs. However unlike those animals, Magyarosuchus had tail vertebrae that show the beginnings of a tail fluke.^[1] Additionally, it was the largest metriorhynchoid outside the family Metriorhynchidae, measuring about 4.67–4.83 metres (15.3–15.8 ft) in body length. This combination of traits show that Magyarosuchus represents a transitional form between the fully ocean going metriorhynchids and their earlier non-marine ancestors.

The cladogram below is from a 2024 study on the phylogenetic relationships of thalattosuchians.^[2]

Metriorhynchoidea	Pelagosaurus typus Teleidosaurus calvadosii Metriorhynchoidea indet. Magyarosuchus fitosi "Pelagosaurus" tomarensis Opisuchus meieri Eoneustes bathonicus Eoneustes gaudryi Euthalattosuchia Chile metriorhynchoid Zoneait nargorum Metriorhynchidae Geosaurinae Metriorhynchinae

Ecology

Magyarosuchus was discovered in the Kisgerecse Marl Formation, whose deposits indicate a more open-ocean environment. It represents the oldest known thalattosuchian adapted to such conditions, rather than to coastal or lagoonal habitats. The frequent occurrence of ammonite fossils in these rocks further supports that this ecosystem was an open ocean.^[1]

The adaptations of Magyarosuchus for life in the open ocean, combined with the abundance of ammonite fossils in its environment, may suggest that it may have been a pursuit predator specializing in ammonites.^[1]