''Montsecosuchus'' 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 ...

of atoposaurid

crocodylomorph Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably mor ...

s. It is the replacement generic name for ''Alligatorium depereti'', which was described in 1915 from the Montsec

Lithographic Limestone Lithographic limestone is hard limestone that is sufficiently fine-grained, homogeneous and defect-free to be used for lithography. Geologists use the term "lithographic texture" to refer to a grain size under 1/250 mm. The term "sublitho ...

quarry A quarry is a type of open-pit mining, open-pit mine in which dimension stone, rock (geology), rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some juri ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

. Fossils found from this locality are from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

, being Upper

Berriasian In the geological timescale, the Berriasian is an age/ stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 143.1 ±0.6 Ma and 137.05 ± 0.2 (million years ago) ...

-Lower

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...

in age, belonging to the

La Pedrera de Rúbies Formation The La Pedrera de Rúbies Formation, also called as La Pedrera de Meià is an Early Cretaceous ( late Berriasian to early Barremian geologic formation in Catalonia, Spain. The formation crops out in the area of the Montsec in the Organyà Bas ...

While many publications concerning atoposaurids after 1915 have included mentions of ''A. depereti'', none has offered a redescription or revision of the species, though some recognized that great differences existed between it and other members of the genus. In these publications, the skull of ''A. depereti'' was shorter in relation to body length than any other species of '' Alligatorium'' (being less than half of the presacral length), and this may have been evidence for the genetic distinction of the species, although no replacement name was proposed. However, better preparation of the holotype specimen MGB 512, a nearly complete articulated skeleton embedded in a limestone matrix now housed in the Museu de Ciències Naturals de Barcelona, allowed for a revision of the species in 1990 in which the name ''Montsecosuchus'' was first used. Montsecosuchus depereti P1270132

''Montsecosuchus'' differs in several ways from other atoposaurids such as ''Alligatorium'', '' Alligatorellus'', and '' Theriosuchus''. Several characteristics of the skull including the presence of an ungrooved parietal-

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestra ...

suture and a caudally projecting retroarticular process distinguish ''Montsecosuchus'' from these genera. Both ''Montsecosuchus'' and ''Alligatorellus'' possess three sacral vertebrae; this may be a shared

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy sh ...

of the two genera. The shortness of the

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

is an autapomorphy of the genus that is not seen in any other atoposaurid, although it is common in more derived crocodylomorphs.

References

{{Taxonbar, from=Q6906561 Neosuchia Early Cretaceous reptiles of Europe Early Cretaceous crocodylomorphs of Europe Cretaceous Spain Fossils of Spain La Huérguina Formation Prehistoric pseudosuchian genera