Dromaeosaurinae
Encyclopedia
Dromaeosaurinae is a subfamily of Dromaeosauridae
. Most dromaeosaurines lived in what is now the USA and Canada
, (Dromaeosaurus, Utahraptor), as well as Mongolia
, (Achillobator, Adasaurus), and possibly Denmark
, (Dromaeosauroides), as well. Isolated teeth that may belong to African dromaeosaurines have also been discovered in Ethiopia
. These teeth date to the Tithonian
stage, of the Late Jurassic
Period.
All North American and Asian dromaeosaurines from Late Cretaceous
were generally small, no more than 1.8 metres long, in Dromaeosaurus
and Adasaurus
. Howewer, among the dromaeosaurines were the largest dromaeosaurs ever; Achillobator
was 6 metres long, and Utahraptor
7.5.
Dromaeosaurines are distinguished from other dromaeosaurids in having stouter, box-shaped skulls, as opposed to the other subfamilies, which generally have narrower snouts. Also, dromaeosaurines are generally more heavily-built, than the other members of their family, with thick, heavy-set legs, which were designed more for strength, rather than for speed.
Also, dromaeosaurines are distinguished from velociraptorines, in having a low DSDI ratio; i.e., their teeth have equal-sized serrations, on both the posterior and on the anterior edges. By contrast, velociraptorines often have larger serrations on the posterior side of the tooth, than the anterior, or no serrations on the anterior side at all.
Most dromaeosaurines lived during the Cretaceous period, from the Barremian
to the Maastrichtian
stages. However, as stated previously, at least one taxon must have lived much earlier, during the Jurassic Period.
Dromaeosauridae
Dromaeosauridae is a family of bird-like theropod dinosaurs. They were small- to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek dromeus meaning 'runner' and sauros meaning 'lizard'...
. Most dromaeosaurines lived in what is now the USA and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, (Dromaeosaurus, Utahraptor), as well as Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
, (Achillobator, Adasaurus), and possibly Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
, (Dromaeosauroides), as well. Isolated teeth that may belong to African dromaeosaurines have also been discovered in Ethiopia
Ethiopia
Ethiopia , officially known as the Federal Democratic Republic of Ethiopia, is a country located in the Horn of Africa. It is the second-most populous nation in Africa, with over 82 million inhabitants, and the tenth-largest by area, occupying 1,100,000 km2...
. These teeth date to the Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
stage, of the Late 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...
Period.
All North American and Asian dromaeosaurines from 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...
were generally small, no more than 1.8 metres long, in Dromaeosaurus
Dromaeosaurus
Dromaeosaurus was a genus of theropod dinosaur which lived during the Late Cretaceous period , sometime between 76.5 and 74.8 million years ago, in the western United States and Alberta, Canada. The name means 'running lizard'....
and Adasaurus
Adasaurus
Adasaurus is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous Period of what is now Central Asia. It was a small bipedal carnivore with a sickle-shaped claw on the second toe of each hind foot. An adult was perhaps about long....
. Howewer, among the dromaeosaurines were the largest dromaeosaurs ever; Achillobator
Achillobator
Achillobator is a genus of dromaeosaurid theropod dinosaur from the late Cretaceous Period of what is now Mongolia, about 90 million years ago. It was probably an active bipedal predator, hunting with the large sickle-shaped claw on the second toe of each hind foot...
was 6 metres long, and Utahraptor
Utahraptor
Utahraptor is a genus of theropod dinosaurs, including the largest known members of the family Dromaeosauridae. Fossil specimens date to the upper Barremian stage of the early Cretaceous period...
7.5.
Dromaeosaurines are distinguished from other dromaeosaurids in having stouter, box-shaped skulls, as opposed to the other subfamilies, which generally have narrower snouts. Also, dromaeosaurines are generally more heavily-built, than the other members of their family, with thick, heavy-set legs, which were designed more for strength, rather than for speed.
Also, dromaeosaurines are distinguished from velociraptorines, in having a low DSDI ratio; i.e., their teeth have equal-sized serrations, on both the posterior and on the anterior edges. By contrast, velociraptorines often have larger serrations on the posterior side of the tooth, than the anterior, or no serrations on the anterior side at all.
Most dromaeosaurines lived during the Cretaceous period, from the Barremian
Barremian
The Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...
to the Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
stages. However, as stated previously, at least one taxon must have lived much earlier, during the Jurassic Period.