Morrinhosuchus
Encyclopedia
Morrinhosuchus is an extinct genus
of notosuchia
n crocodyliform from the Late Cretaceous
Adamantina Formation
of Brazil
. It is known from a mandible
and a portion of the front of the skull collected from the municipality of Monte Alto in São Paulo
state. Morrinhosuchus refers to Morrinho de Santa Luzia, a hill nearby the collection site of the holotype
, while luziae refers to the chapel of Santa Luzia, which is located on top of the hill.
The skull and jaws are posteriorly broad but narrow significantly toward the front. The teeth at the back of the jaw are bulbous in shape and circular in cross-section (this shape is only found in one other notosuchian, Mariliasuchus
, also from the Adamantina Formation). The mandible arches upward. The symphysis
, or area where the two sides of the lower jaw meet, is formed mostly by the mandibles but also partly by the splenial
s. The skull preserves an antorbital fenestra
, or opening in front of the eyes. The nasal
, a bone at the top of the skull behind the nostrils, is relatively long. There is also a small notch at the contact between the premaxilla
and the maxilla
near the front of the snout.
Morrinhosuchus can be distinguished from Mariliasuchus on the basis of several unique features. For example, there is a gap between the maxilla and the palatine bone
around the midline of the palate. The palate itself is also wider than that of Mariliasuchus. While the teeth of the two genera are very similar, their number and placement in the jaw differs slightly. Morrinhosuchus has seven post-caniniform teeth while Mariliasuchus has only six. There are also differences in the shape of the rostrum between the two genera, as Morrinhosuchus has a higher, more pointed snout with less constriction than in Mariliasuchus.
The Adamantina Formation, which is Turonian
to Santonian
in age, was deposited in semi-arid conditions around 95 million years ago. Morrinhosuchus was found in an outcrop of reddish sandstone
with carbonate
nodules
, concretion
s, and areas of intense bioturbation
. The Adamantina Formation is part of the larger Bauru Basin, from which several other notosuchians have been found. These include Sphagesaurus
, Mariliasuchus, Adamantinasuchus
, Armadillosuchus
, and Baurusuchus
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of notosuchia
Notosuchia
Notosuchia is a suborder of primarily Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Cretaceous. Fossils have been found from South America, Africa, and Asia...
n crocodyliform 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...
Adamantina Formation
Adamantina Formation
The Adamantina Formation 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...
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...
. It is known from a mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
and a portion of the front of the skull collected from the municipality of Monte Alto in São Paulo
São Paulo (state)
São Paulo is a state in Brazil. It is the major industrial and economic powerhouse of the Brazilian economy. Named after Saint Paul, São Paulo has the largest population, industrial complex, and economic production in the country. It is the richest state in Brazil...
state. Morrinhosuchus refers to Morrinho de Santa Luzia, a hill nearby the collection site of the holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, while luziae refers to the chapel of Santa Luzia, which is located on top of the hill.
The skull and jaws are posteriorly broad but narrow significantly toward the front. The teeth at the back of the jaw are bulbous in shape and circular in cross-section (this shape is only found in one other notosuchian, Mariliasuchus
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....
, also from the Adamantina Formation). The mandible arches upward. The symphysis
Symphysis
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.1.A symphysis is an amphiarthrosis, a slightly movable joint.2.A growing together of parts or structures...
, or area where the two sides of the lower jaw meet, is formed mostly by the mandibles but also partly by the splenial
Splenial
The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side between the angular and suprangular....
s. The skull preserves an antorbital fenestra
Antorbital fenestra
An antorbital fenestra is an opening in the skull, in front of the eye sockets. This skull formation first appeared in archosaurs during the Triassic Period. Living birds today possess antorbital fenestrae, but the feature has been lost in modern crocodilians...
, or opening in front of the eyes. The nasal
Nasal bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....
, a bone at the top of the skull behind the nostrils, is relatively long. There is also a small notch at the contact between the premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
and the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
near the front of the snout.
Morrinhosuchus can be distinguished from Mariliasuchus on the basis of several unique features. For example, there is a gap between the maxilla and the palatine bone
Palatine bone
The palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
around the midline of the palate. The palate itself is also wider than that of Mariliasuchus. While the teeth of the two genera are very similar, their number and placement in the jaw differs slightly. Morrinhosuchus has seven post-caniniform teeth while Mariliasuchus has only six. There are also differences in the shape of the rostrum between the two genera, as Morrinhosuchus has a higher, more pointed snout with less constriction than in Mariliasuchus.
The Adamantina Formation, which is Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
to Santonian
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...
in age, was deposited in semi-arid conditions around 95 million years ago. Morrinhosuchus was found in an outcrop of reddish sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
with carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
nodules
Nodule (geology)
A nodule in petrology or mineralogy is a secondary structure, generally spherical or irregularly rounded in shape. Nodules are typically solid replacement bodies of chert or iron oxides formed during diagenesis of a sedimentary rock...
, concretion
Concretion
A concretion is a volume of sedimentary rock in which a mineral cement fills the porosity . Concretions are often ovoid or spherical in shape, although irregular shapes also occur. The word 'concretion' is derived from the Latin con meaning 'together' and crescere meaning 'to grow'...
s, and areas of intense bioturbation
Bioturbation
In oceanography, limnology, pedology, geology , and archaeology, bioturbation is the displacement and mixing of sediment particles and solutes by fauna or flora . The mediators of bioturbation are typically annelid worms , bivalves In oceanography, limnology, pedology, geology (especially...
. The Adamantina Formation is part of the larger Bauru Basin, from which several other notosuchians have been found. These include Sphagesaurus
Sphagesaurus
Sphagesaurus is an extinct genus of notosuchian crocodylomorph from the Late Cretaceous of Brazil.-Species and discovery:The type species S. huenei, was discovered in 1950 by Price, with the both the genus and species named from two isolated teeth. More recently a nearly complete skull of S...
, Mariliasuchus, Adamantinasuchus
Adamantinasuchus
Adamantinasuchus is an extinct genus of notosuchian crocodylomorph from the Late Cretaceous of Brazil.-Phylogeny:Below is a cladogram modified from O’Connor et al., 2010:...
, Armadillosuchus
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...
, and 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...
.