Baurusuchinae is a subfamily of baurusuchid crocodyliforms from the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 of Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. Named in 2011, it contains the baurusuchids Baurusuchus

Baurusuchus

Baurusuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It was a terrestrial predator and scavenger, about 3.5 to 4 meters long. Baurusuchus lived during the Turonian to Santonian stages of the Late Cretaceous Period, in Adamantina Formation, Brazil...

and Stratiotosuchus

Stratiotosuchus

Stratiotosuchus is an extinct genus of baurusuchid mesoeucrocodylian which existed in the Adamantina Formation, Brazil during the late Cretaceous period . It was first named by Campos, D.A., Suarez, J.M., Riff, D. and Kellner, A.W.A. in 2001 and the type species is Stratiotosuchus maxhechti...

. Baurusuchinae is one of two subfamilies of Baurusuchidae, the other being Pissarrachampsinae

Pissarrachampsinae

Pissarrachampsinae is a subfamily of baurusuchid crocodyliforms from the Late Cretaceous of Brazil and Argentina. It was named in 2011 with the description of Pissarrachampsa sera and includes P. sera from Brazil and the related Wargosuchus australis from Argentina...

.

Several features distinguish baurusuchines from pissarrachampsines and help diagnose the subfamily. The two prefrontal bone

Prefrontal bone

The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most modern and extinct lungfish, amphibians and reptiles...

s on the top of the skull are connected along a small length of midline of the skull, while those of pissarrachampsines touch only at a small point. The frontal bone

Frontal bone

The frontal bone is a bone in the human skull that resembles a cockleshell in form, and consists of two portions:* a vertical portion, the squama frontalis, corresponding with the region of the forehead....

, situated behind the prefrontals, is very wide. Baurusuchines also have ridges on parts of their palate

Palate

The palate is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but, in most other tetrapods, the oral and nasal cavities are not truly separate. The palate is divided into two parts, the anterior...

. The quadratojugal

Quadratojugal

The quadratojugal is a small jaw bone that is present in most amphibians, reptiles, and birds, but has been lost in mammals. It is connected to the jugal as well as other bones, though these may vary with species....

, a bone within a depression of the skull behind the eye called the laterotemporal fenestra, extends up to the rim of the fenestra or ends just below it. There is also a straight or somewhat curved muscle scar on the medial surface of the quadrate bone

Quadrate bone

The quadrate bone is part of a skull in most tetrapods, including amphibians, sauropsids , and early synapsids. In these animals it connects to the quadratojugal and squamosal in the skull, and forms part of the jaw joint .- Evolutionary variation :In snakes, the quadrate bone has become elongated...

.

Baurusuchinae is a stem-based taxon defined in 2011 as Baurusuchus pachecoi

Baurusuchus

Baurusuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It was a terrestrial predator and scavenger, about 3.5 to 4 meters long. Baurusuchus lived during the Turonian to Santonian stages of the Late Cretaceous Period, in Adamantina Formation, Brazil...

and all crocodyliforms more closely related to it than to Pissarrachampsa sera

Pissarrachampsa

Pissarrachampsa is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil...

, Notosuchus terrestris

Notosuchus

Notosuchus is an extinct genus of South American notosuchian crocodylomorph. It was terrestrial, living approximately 85 million years ago in the Coniacian or Santonian stages of the Late Cretaceous. Remains have been found in the Bajo de la Carpa Formation in Patagonia, Argentina. First named in...

, Mariliasuchus amarali

Mariliasuchus

Mariliasuchus is an extinct genus of Late Cretaceous notosuchian mesoeucrocodylian found near Marilia, Brazil. It was described in 1999 by Brazilian palaeontologists Ismar de Souza Carvalho and Reinaldo J. Bertini....

, Armadillosuchus arrudai

Armadillosuchus

Armadillosuchus is an extinct genus of sphagesaurid crocodylomorph. It was described in February 2009 from the Late Cretaceous Bauru Basin of Brazil. Sphagesaurids share a number of mammal-like features in their teeth and jaws, although they are unrelated to mammals...

, Araripesuchus gomesi

Araripesuchus

Araripesuchus is a genus of extinct crocodyliform whose species existed during the Cretaceous period of the late Mesozoic era some 125 to 65 million years ago. They are generally considered to be notosuchians , characterized by their varied teeth types and distinct skull elements...

, Sebecus icaeorhinus

Sebecus

Sebecus is an extinct genus of sebecid crocodylomorph from the Eocene of South America. Fossils have been found in Patagonia. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by a single species, the type S. icaeorhinus...

, Bretesuchus bonapartei

Bretesuchus

Bretesuchus is an extinct genus of sebecosuchian mesoeucrocodylian within the family Bretesuchidae. Fossils have been found from the Maíz Gordo Formation of northwestern Argentina and date back to the late Paleocene...

, Peirosaurus tormini

Peirosaurus

Peirosaurus is an extinct genus of peirosaurid crocodylomorph. It is the type genus of the family Peirosauridae. Fossils of the type species P. tormini, first described in 1955, have been found from the Marília Formation in Uberaba, Brazil and date back to the late Maastrichtian stage of the Late...

, and Crocodylus niloticus.

Baurusuchines are only found in the Bauru Basin of Brazil, and are therefore endemic to the Bauru Group

Bauru Group

The Bauru Group is a geological formation in Brazil whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation. The Bauru Group was divided by Fernandes and Coimbra in four formations,namely Adamantina, Uberaba Araçatuba and...

. Because of their restricted stratigraphic and geographic range, baurusuchines were probably sympatric, living in the same environment at the same time. Alternatively, they may have been stratigraphically separated, meaning that each species lived at a slightly different time.