"Ankylosauridae".

Old DINOSAURS Ankylosauridae (/ˌæŋkɪloʊˈsɔːrɪdiː/) is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Paleogene extinction event.[1] These animals were mainly herbivorous and were obligate quadrupeds, with leaf-shaped teeth and robust, scute-covered bodies. Ankylosaurids possess a distinctly domed and short snout, wedge-shaped osteoderms on their skull, scutes along their torso, and a tail club.[2]

Ankylosaurids

Temporal range: Early Cretaceous - Late Cretaceous, 133–66 Ma 

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Mounted skeleton of Scolosaurus thronus, Royal Tyrrell Museum of PalaeontologyScientific classificationDomain:EukaryotaKingdom:AnimaliaPhylum:ChordataClade:DinosauriaClade:†OrnithischiaClade:†ThyreophoraSuborder:†AnkylosauriaClade:†EuankylosauriaFamily:†Ankylosauridae
Brown, 1908Type species†Ankylosaurus magniventris

Brown, 1908

Subgroups

†Aletopelta

†Bissektipelta

†Cedarpelta

†Chuanqilong

†Crichtonsaurus

†Gobisaurus

†Liaoningosaurus

†Maleevus?

†Minmi

†Shamosaurus

†Ankylosaurinae

Synonyms

Syrmosauridae Maleev, 1952

Ankylosauridae is exclusively known from the northern hemisphere, with specimens found in western North America, Europe, and East Asia. The first discoveries within this family were of the genus Ankylosaurus, by Peter Kaiser and Barnum Brown in Montana in 1906.[3] Brown went on to name Ankylosauridae and the subfamily Ankylosaurinae in 1908.

Anatomy

History of study

PhylogenyEdit

Club of indeterminate ankylosaurine, CMN 349

In 1978, W.P. Coombs, Jr. classified almost all valid species of Ankylosauria within either Nodosauridae or Ankylosauridae.[9] This was a pivotal study and described many characters of ankylosaurs in the earliest phylogenetic analyses of the group.

Later in 1998, Paul Sereno formally defined Ankylosauridae as all ankylosaurs more closely related to Ankylosaurus than to Panoplosaurus.[10] Ankylosaurs not known to possess a tail club were included in Kenneth Carpenter's 2001 phylogeny of Ankylosauridae.[11]

In a study done in 2004 by Vickaryous et al., Gargoyleosaurus, Gastonia, and Minmi were recorded as basal ankylosaurids, with the rest of the ankylosaurids filled out with Gobisaurus, Shamosaurus, and ankylosaurines from China, Mongolia, and North America.[12]

In 2012, Thompson et al. undertook an analysis of almost all known valid ankylosaurs and outgroup taxa at the time.[13] They based their resulting phylogeny on characters representing cranial, post-cranial, and osteodermal anatomy, and details of synapomorphies for each recovered clade. This study placed Gargoyleosaurus and Gastonia within basal Nodosauridae, and put Cedarpelta and Liaoningosaurus as basal ankylosaurids.[13]

Huayangosaurus taibaii

Stegosaurus armatus

Nodosauridae

Ankylosauridae

Minmi paravertebra

Liaoningosaurus paradoxus

Cedarpelta bilbeyhallorum

Gobisaurus domoculus

Shamosaurus scutatus

Zhongyuansaurus luoyangensis

Tsagantegia longicranialis

Shanxia tianzhensis

"Crichtonsaurus" benxiensis

Dyoplosaurus acutosquameus

Pinacosaurus mephistocephalus

Ankylosaurus magniventris

Euoplocephalus tutus

Minotaurasaurus ramachandrani

Pinacosaurus grangeri

Nodocephalosaurus kirtlandensis

Talarurus plicatospineus

Tianzhenosaurus youngi

Saichania chulsanensis

Tarchia gigantea

Gastonia and other polacanthine dinosaurs have uncertain placement, possibly within Ankylosauridae

In 2016, Arbour and Currie have presented a phylogenetic analysis of Ankylosauridae consisting of Gastonia, Cedarpelta, Chuanqilong, other basal ankylosaurids, and a number of derived ankylosaurids. Their phylogeny includes some uncertain phylogenetic relationships, between Ankylosaurus, Anodontosaurus, Scolosaurus, and Ziapelta.[14]