Mirischia
Encyclopedia
Mirischia is a small extinct genus
of compsognathid dinosaur
from the Albian
stage (Early Cretaceous
period) of Brazil
. Though presently known only from a pelvis and incomplete hind limbs, it preserves enough information to show that it should be recognized as a distinct species. Some phylogenetic studies incorporating this specimen have found it to be a compsognathid closely related to Compsognathus
from the Upper Jurassic
of Europe and Aristosuchus
from the Lower Cretaceous
of England, although it could also be a basal Tyrannosauroid
.
Mirischia is notable for having asymmetrical ischia. Quoting from Naish
et al. (2004): "The ischia of Mirischia are asymmetrical, that on the left being perforated by an oval foramen while that on the right has an open notch in the same position." The specimen is also unusual in that it originally preserved some soft tissue remains: what appears to have been an air sac was preserved between its pubic and ischial bones. Previous workers had suggested that non-avian theropods might - like birds - possess post-cranial air sacs, and Mirischia seems to confirm that.
mirus, 'wonderful'; "ischia": Greek
, pertaining to the whole pelvis, and not the ischia alone. "asymmetrica": From its asymmetrical ischia.
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 compsognathid dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
from the Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
stage (Early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
period) 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...
. Though presently known only from a pelvis and incomplete hind limbs, it preserves enough information to show that it should be recognized as a distinct species. Some phylogenetic studies incorporating this specimen have found it to be a compsognathid closely related to Compsognathus
Compsognathus
Compsognathus was a small, bipedal, carnivorous theropod dinosaur. The animal was the size of a turkey and lived around 150 million years ago, the early Tithonian stage of the late Jurassic Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany...
from the Upper Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
of Europe and Aristosuchus
Aristosuchus
Aristosuchus was a small coelurosaurian dinosaur, whose name was derived from the Greek ἄριστος and σουχος, the Ancient Greek corruption of the name of the Egyptian crocodile-headed god Sobek. It shared many characteristics with birds.Aristosuchus was a bipedal, meat-eating theropod dinosaur...
from the Lower Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
of England, although it could also be a basal Tyrannosauroid
Tyrannosauroidea
Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period...
.
Mirischia is notable for having asymmetrical ischia. Quoting from Naish
Naish
Naish might refer to:* J. Carrol Naish , an American actor* The Naish District in Afghanistan* Robby Naish windsurfer and kitesurfer, also Naish kites, sails and boards* Darren Naish zoologist, science writer and dinosaur expert...
et al. (2004): "The ischia of Mirischia are asymmetrical, that on the left being perforated by an oval foramen while that on the right has an open notch in the same position." The specimen is also unusual in that it originally preserved some soft tissue remains: what appears to have been an air sac was preserved between its pubic and ischial bones. Previous workers had suggested that non-avian theropods might - like birds - possess post-cranial air sacs, and Mirischia seems to confirm that.
Etymology
"Mir": from LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
mirus, 'wonderful'; "ischia": Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
, pertaining to the whole pelvis, and not the ischia alone. "asymmetrica": From its asymmetrical ischia.