Suchoolithus

Fossil crocodylian eggs are generally rare, though they have been discovered worldwide (excepting Antarctica and Australia). In 2008, the Portuguese paleontologist Octávio Mateus discovered a fossilized egg clutch at the Lourinhã Formation of Portugal that would later become holotype of Suchoolithus.^[1] These eggs were first described in 2014 by Russo, Mateus, Balbino, and Marzola, who at the time tentatively referred them to Krokolithes, but noted their similarities to the Krokolithid Bauruoolithus.^[2] In 2016, João Russo, working with Octávio Mateus as his supervisor and Balbino as co-supervisor, completed his Master's Thesis at Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, in which he named the oogenus and oospecies Suchoolithus portucalensis (meaning "crocodile egg stone from Portugal").^[3] The next year, Russo, Mateus, Marzola, and Balbino published the description of Suchoolithus in PLOS One.^[1]

Suchoolithus is known exclusively from the upper Tithonian of the Late Jurassic Lourinhã Formation of Portugal, making it (alongside Krokolithes dinophilus) the oldest known crocodylomorph egg.^[1] This formation, representing the deposits of river deltas and alluvial fans, has similar fauna and flora to the contemporaneous Morrison Formation in the United States and the Tendaguru Formation in Tanzania.^[4] Several types of crocodylomorphs are known from the late Jurassic of Portugal, but given the small size of the eggs, it is most likely that Suchoolithus were laid by one of the smaller species (perhaps less than 1 m (3.3 ft) long), such as Bernissartia, cf. Alligatorium, Lisboasaurus, Lusitanisuchus, or Theriosuchus.^[1]