''Mariliasuchus'' ("Marilia crocodile") is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

notosuchia Notosuchia is a clade of primarily Gondwanan mesoeucrocodylian Crocodylomorpha, crocodylomorphs that lived during the Jurassic and Cretaceous. Some phylogeny, phylogenies recover Sebecosuchia as a clade within Notosuchia, others as a sister group ...

crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ...

s found near Marilia,

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. The first bone remains were found and collected in 1995 by Brazilian paleontologist William Nava, in red rocks from the

fossiliferous A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved i ...

Adamantina Formation The Adamantina Formation is a geological Formation (geology), formation in the Bauru Basin of western São Paulo (state), São Paulo state in southeastern Brazil. Its strata date back to the Late Cretaceous epoch of the Cretaceous, Cretaceous Per ...

.''Mariliasuchus''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org Four years later, it was described as ''Mariliasuchus amarali'', by Brazilian

paleontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

s Ismar de Souza Carvalho and Reinaldo J. Bertini. Its type species ''M. amarali'', in honour of Sérgio Estanislaw do Amaral, Brazilian

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

. A second species, ''M. robustus'', was named in 2007.pdf

Discovery

Several specimens of ''M. amarali'' have been found close to eggs, eggshells and

coprolite A coprolite (also known as a coprolith) is fossilized feces. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. The name ...

s to date: UFRJ DG 50-R (holotype): a partially complete and articulated skeleton, including a nearly complete skull and partially preserved axial and appendicular skeletons. It belongs to a juvenile specimen. UFRJ DG 105-R. UFRJ DG 106-R. MZSP-PV 50. MZSP-PV 51. MN 6298-V. MN 6756-V. URC R 67. URC R 68. URC R 69. MPM 114 Ic V - 4 eggs. MPM 115 R. MPM 116 R. MPM 117 R. MPM 119 R. All of these specimens have been recovered in a road cut, south from the city of Marilia, in outcrops known as "Estrada Velha" pto. 1 and 2. They come from the upper part of the

, indicating a Late Cretaceous (possibly Campanian/Maastrichtian) age. The findings by William Nava could be found in the

National Museum of Brazil National may refer to: Common uses * Nation or country ** Nationality – a ''national'' is a person who is subject to a nation, regardless of whether the person has full rights as a citizen Places in the United States * National, Maryland, ...

, but they were partially destroyed in the 2018's

National Museum of Brazil fire The National Museum of Brazilmuseum was heavily damaged by a large fire which began about 19:30 local time (23:30 UTC) on 2 September 2018. Although some items were saved, it is believed that 92.5% of its archive of 20 million items was destroye ...

Classification

A phylogenetic analysis done by Zaher et al. (2006) found ''Mariliasuchus amarali'' to share a close relationship with '' Comahuesuchus''. Andrade et al. (2006), while studying the palate and choanae of some mesoeucrocodylians, reached this same conclusion. Though no name was given to this clade in either publication, it is referred in this article as Comahuesuchidae.

Palaeobiology

Size of Brazilian fossil crocodylomorphs

''Mariliasuchus'', unlike modern crocodylians, was an animal of terrestrial habits (though see below). Its nostrils were located on the front of the skull, unlike modern crocodiles, in which the nostrils face upwards, to help the animal breathe while its almost completely submerged. Furthermore, the eyes in ''M. amarali'' are faced laterally (in modern crocodiles they face upwards). It had a very modified dentition, differentiated in incisiforms, caniforms and molariforms. Strangely, in particular, were the anterior-most teeth, which were directed horizontally rather than vertically. The function of this strange arrangement is not yet clear, but Vasconcellos et al. (2002) made comparisons with the dentition of

pigs The pig (''Sus domesticus''), also called swine (: swine) or hog, is an omnivorous, domesticated, even-toed, hoofed mammal. It is named the domestic pig when distinguishing it from other members of the genus '' Sus''. Some authorities cons ...

, indicating that their dietary preferences may be convergent. It also had strong jaw muscles, indicating a good degree of mandibular activity. There seems to be a significant degree of variation between specimens of ''M. amarali''. Some of this is related to ontogenetic variation, but some may also suggest sexual dimorphism, or even that some of the specimens assigned to this species belong to a different animal. Ontogenetic studies done by Vasconcellos and Carvalho (2005) concluded that during its growth, the skull of ''M. amarali'' individuals becomes shorter and the skull more resistant, while being laterally compressed. In adulthood, the orbit has a less circular arrangement than in younger individuals. The postcranial skeleton of ''Mariliasuchus amarali'' displays a mixture of traits similar to those present in the skeleton of Cretaceous terrestrial crocodyliform ''

Notosuchus ''Notosuchus'' (; 'southern crocodile') is an extinct genus of South American notosuchian crocodyliforms. It was terrestrial, living approximately 85 million years ago in the Santonian stage of the Late Cretaceous. Description ''Notosuchus'' ...

'' and traits present in aquatic

eusuchia Eusuchia is a clade of neosuchian Crocodylomorpha, crocodylomorphs that first appeared in the Early Cretaceous, which includes modern Crocodilia, crocodilians. Along with Dyrosauridae and Sebecosuchia, they were the only crocodyliformes who survi ...

n crocodyliform, including living crocodilians. Nobre and Carvalho (2013) inferred that ''Mariliasuchus'' did not have an erect or semi-erect posture, but rather a sprawling posture and, possibly, had amphibian habits similar to those of living crocodilians.

Discovery

Classification

Palaeobiology

References

Further reading