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Useful Notes / Prehistoric Life - Ankylosaurs

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The Colorful Ankylosaur

Other than the clubbed Ankylosaurus and Euoplocephalus/Scolosaurus, frequently-portrayed North American ankylosaurs include the club-less Nodosaurus, Sauropelta, Edmontonia, and Gastonia. The European Polacanthus and Hylaeosaurus have been common sights as well because of their historical relevance, while Pinacosaurus is the most-often seen Asian ankylosaur. Among kinds found in other continents you might see Minmi from Australia, as well as a mention of the "Antarctic ankylosaur" Antarctopelta as it was the very first dinosaur found there, though it isn't often named. The animal of the image is the recently-found Borealopelta.

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    Clubbed Ankylosaurs 

Ankylosaurs from the West: Dyoplosaurus

  • Ankylosaurus magniventris and the "Euoplocephalus wastebin" made of Euoplocephalus and Scolosaurus have long been considered the only Late Cretaceous North American members of the club-tailed family, the Ankylosaurids. Recently, brand-new animals have been found; one of them has received the name Nodocephalosaurus ("lizard with tubercled head"), resembling a Portmanteau of Nodo(saurus) and (Euoplo)cephalus plus the usual suffix -saurus. Dyoplosaurus ("double-armored lizard") was found much earlier, at the same time of Scolosaurus and Euoplocephalus, but was long confused with them in paleontology. Some in the past attributed to it the famous fossil of Montana with today is assigned to the genus Scolosaurus, and even the first-found fossils of the mongolian Tarchia (see below).

Ankylosaurs from the East: Talarurus

  • Many ankylosaurines (the clubbed ankylosaurids) are known from Asia, mostly from Late Cretaceous: Pinacosaurus is the most common in fossil record, but there were many others. Particularly worthy of note both for their historical relevance and for their fossil completeness are Tarchia, Saichania, and Talarurus. Talarurus ("basket tail") was the second Asian ankylosaur discovered after Pinacosaurus, more precisely in the Russian expedition led by Ivan Efremov; it had a narrow head, rather similarly to a nodosaur but with the typical four hornlets of ankylosaurids, and short limbs. Surprisingly, Talarurus has appeared at the beginning of the Disney's Dinosaur, although only with a simple unnamed cameo. Though not described yet, "Hanwulosaurus" could actually be the biggest Asian ankylosaur: 9 m long, bigger than Tarchia itself. It is known from a rather complete skeleton, but until the official description we cannot say much more about it. Some think it belongs to its own subgroup of ankylosaurians.

Smart and Beautiful: Tarchia & Saichania

  • Tarchia, the biggest described Asian ankylosaur, has more than one species known, and might be considered as the asiatic version of the North-American Ankylosaurus — while Pinacosaurus and Talarurus could be quoted as the versions of the smaller Euoplocephalus and Scolosaurus (also North-American). Tarchia was similar in look to Ankylosaurus, and the complete name of its original species was "Tarchia gigantea" (gigantea = gigantic), now invalid. This short-named ankylosaur appears in Prehistoric Planet as one of the Late Cretaceous dinosaurs of Asia. Both Saichania and Tarchia were described in the 1970s within the third historical expedition in Mongolia, this time led by Polish scientists, but while Saichania was dug out just in this expedition, Tarchia has been already known to science but initially believed the Asian species of the North-American Dyoplosaurus. 8.5 m long, Tarchia is the biggest described Asian ankylosaur, as large as Ankylosaurus; but Saichania too was very large (7 m), bigger than the 6 m long Euoplocephalus or the 5 m long Pinacosaurus. Both ankylosaurs have names that can appear funny for some: Tarchia in Mongolian means “brainy” (its first remain found was a skull with a large braincase) and Saichania in Mongolian means “beautiful” (a reference to the beauty of its well-preserved skeleton). They were among the last-surviving Asian ankylosaurs, and thanks to their size both should have been hard targets for every predator when adults, even for the mighty Tarbosauruses (which were slightly smaller, less-powerful cousins of the North American Tyrannosauruses). Also interesting is Minotaurasaurus (the "minotaur dinosaur", found in 2009), similar to Tarchia & Saichania but with unusually-long "horns" —- hence its name. Like Tarchia, Saichania was rather similar in look to Ankylosaurus, and has made it into popular culture recently thanks to recurring antagonist dinosaur Tank from Dinosaur King.

Almost-Clubbed: Shamosaurus & Gobisaurus

  • Shamosaurus and Gobisaurus were both primitive Early Cretaceous ankylosaurids outside the Ankylosaurines, their names both meaning "lizard from the Gobi Desert". Being primitive ankylosaurids they still hadn't a true "club" yet, but their descendants developed the classic club. Other ankies from China/Mongolia include Liaoningosaurus (which some believe semi-aquatic), Maleevus (named after the scientist Maleev), Sauroplites ("soldier lizard"), Shanxia (from Shan-Xi), Sinankylosaurus ("Chinese Ankylosaurus"), the deceptively-named Stegosaurides ("false Stegosaurus"), Tianzhenosaurus (from Tian-Zhen), and Tsagantegia (Tsagan is a Mongolian word). Many of them are known from fragmentary remains. Some, belonging to the Ankylosaurines, were surely tail-clubbed.

Chilean Macuahuitl: Stegouros

  • Stegouros elengassen was found in 2018 in southern Chile. A very small ankylosaur, only about 2.0 m long and 100 kg, Stegouros was not an ankylosaurid but a much more primitive form, similarly to the Australian Minmi: in the past it would have been classified in the "nodosaur" ensemble. Stegouros'most distinctive trait is its tail: very short and with a very different armor than the one of the ankylosaurines. Whereas the latter had the club at the tip of the tail that was fully fused to form one solid mass, Stegouros had stegosaur-like plates down the full length of its tail (Stegouros just means "roofed tail", Stegosaurus means "roofed lizard", and Stegoceras "roofed horn") that were only partially fused - thus allowing the tail to retain some articulation - with closely-packed pointed plates down each side of the tail. This has been compared to the Aztec macuahuitl, a paddle-shaped wooden war club with obsidian blades embedded in its sides. While Stegouros' tail spikes wouldn't have been nearly as sharp as obsidian blades, they would still be an efficient weapon. Its small size meant that this would have been little protection if a hungry carcharodontosaur or abelisaur found it, though those apex predators of South America probably preferred larger prey since a small dinosaur wouldn't be much of a meal to them.

    Clubless Ankylosaurs 

Ankylosaurs Conquer the USA: "Palaeoscincus"

  • Not only England: even in Usa the first dino-discoveries included an ankylosaur, one even more incomplete than the Hylaeosaurus of the Crystal Palace Park. “Palaeoscincus” was one of the dinosaurs descibed in 1856 by Joseph Leidy from simple isolated teeth, which initially were believed from a skink-like lizard ("Palaeoscincus" means ancient skink). Many undetermined remains were later assigned to this dinosaur, making “Palaeoscincus” a Waste-Basket taxon, but now they are either regarded as dubious, or classified in other genera. The images of "palaeoscincus"es often seen in old dino-books are actually based upon another better-known ankylosaur, Edmontonia. The first North-American ankylosaur known from decent remains was Nodosaurus. Described during the Bone Wars by Marsh (which also described the teeth of another relative, Priconodon), Nodosaurus ("knobbed lizard") was known only from pieces of armor with no spikes: this explains why, in classic portraits, it appears spikeless and with a generic-looking armor. Actually, the nodosaur should have had lateral spikes like its relatives. Living at the beginning of Late Cretaceous, before Edmontonia but after Sauropelta, Nodosaurus became the prototype of its own family, the Nodosaurids, in which every club-less ankylosaur used once to be put.

Ankies Conquer even Canada: Panoplosaurus

  • More complete nodosaurids appeared in Alberta at the start of the XX century, showing clearly spiky bodies: Panoplosaurus ("wholly-armored lizard") and Edmontonia (so-called because was found near Edmonton, see also Edmontosaurus). Both were large (6 m or so) with a complex armor expecially in the frontal portion of their body. Edmontonia showed a couple of huge shoulder-spikes pointing forwards, often double pointed, but lacked lateral spikes on its trunk and tail. Even though Edmontonia and Panoplosaurus were narrow-headed and devoid of horns or tail-clubs like all nodosaurs, they were surely a difficult task for the tyrannosaurs they shared the world with: maybe were they able yo inflict deep wounds in the carnivores' legs with their big spikes, as seen in modern portrayals. In 1988, famous paleontologist Bob Bakker described two new dubious genera of Late Cretaceous nodosaurs, "Chassternbergia" and "Denversaurus". The first was a homage to Charles Sternberg, one of the main north-american dino-hunters from the first half of the XX century; the second owes its name from the capital of Colorado (Bakker’s state).note  Even though known for only a shattered skull, Denversaurus might have given its name to the hero of a famous TV dino-cartoon broadcast just in those years.

The Pelta Family

  • In the 1970s, John Ostrom (the Deinonychus Trope Namer) described an Early Cretaceous nodosaur from Montana, Sauropelta edwardsorum ("Edward's armored lizard"): Ostrom wasn’t aware of, but started the trend to name ankylosaurs with the suffix –pelta: Dracopelta, Mymoorapelta, Bissektipelta, and many many others (one is just in the next paragraph), all found later than the ur-example except for the dubious "Stegopelta", found at the start of the XX century. Also North American were Silvisaurus, Pawpawsaurus, and Texasetes, smaller relatives. Silvisaurus from Middle Cretaceous was the first discovered of the three, in the same years of Sauropelta; its name (sometimes misspelled "Silviasaurus") means "forest lizard" — the same meaning of Hylaeosaurus, but with a Latin root instead of Greek (similarly to the couple of names Ornithomimus & Avimimus). Pawpawsaurus and Texasetes were both Early Cretaceous and were found in the nineties: the former's name is not a reference to the fruit but to the formation it was dug out, while the latter's one refers to Texas. With its 7.5 long body, Sauropelta was the biggest nodosaurid known: it had a more slender body-frame than Edmontonia and Panoplosaurus, with a longer neck and smaller head; and its armor was simpler than its Late Cretaceous cousins, with small mosaic-like scutes of different size. It had nonetheless lateral spikes all along its body, and those on the shoulders were particularly long and pointing upwards - making Sauropelta a valid opponent for the contemporaneous giant theropods like Acrocanthosaurus. Typical nodosaurids had mosaic-like armor, very different to that of the ankylosaurids, made by wide rows put in line on the upper body. Found in 2008 is another nodosaur from Utah, Peloroplites ("monstrous soldier"), which was only a bit smaller than Sauropelta. Other two nodosaurians found in North America in the 1990s are Animantarx ("living citadel") and Niobrarasaurus (from Niobrara, the famous inland sea which covered the Great Plains during the Cretaceous).

The Colorful Ankylosaur: Borealopelta

  • The most extraordinary discover ever about ankylosaurians happened in 2017 in Canada: in that year was described Borealopelta markmitchelli ("Mark Mitchell's armor of the North"). Early Cretaceous like Sauropelta and nicknamed the Suncor Nodosaur, this middle-sized ankylosaur preserved not only some keratinous sheaths of its armor (a bit like the skin prints of Carnotaurus) and other remains of soft tissues plus stomach contents like the Edmontosaurus mummies: it has even uniquely preserved tracks of the original colors, just like some Liaoning dinosaurs! The fossil, preserved by marine sediments, show it was probably reddish-brown in life. To date, Borealopelta is the only large dinosaur which has left some tracks of its original coloration: this could make it a more popular dinosaur in the future, maybe attracting the pop-writers' interest.

European Ankylosaurs

  • The ankylosaurs found in Europe are usually like the english Hylaeosaurus and Polacanthus: small and clubless. To compensate, some are quite coolly-named. Acanthopholis almost seems Polacanthus inverted; "Polacanthoides" means "false Polacanthus"; Priodontognathus means "saw-toothed jaw"; Struthiosaurus means “Ostrich-Lizard” (making thinking it was Struthiomimus-like…); while Anoplosaurus means "unarmed lizard" (all ankylosaurs were armored). Dracopelta is the “armored dragon”, and "Cryptodraco" (today named Cryptosaurus) the "hidden dragon". But the weirdest-named is Sarcolestes: “meat thief”. Both Sarcolestes and Dracopelta were Jurassic: Sarcolestes, found in Middle Jurassic England, was one of the first proper ankylosaurs to have evolved (together with the north-african Spicomellus, described in 2021), living alongside the early sauropod Cetiosaurus and the large theropod Megalosaurus. Dracopelta and Cryptosaurus were younger, roaming Late Jurassic Portugal and England respectively. Dracopelta lived along with dinosaurs more known for North America, and had already a complex armor for such a primitive ankylosaur. Acanthopholis and Anoplosaurus were Early Cretaceous kinds found in England in the XIX century, but are both known from very scant remains (Anoplosaurus was often thought an ornithopod in the past).

Island-dwelling Dwarf Ankylosaur: Struthiosaurus

  • But it's Struthiosaurus the more interesting ankylosaur of Europe. It has been, indeed, not only the smallest known ankylosaur, but one of the smallest known quadrupedal dinosaurs ever (merely 6 ft, like a large dog). This because it was one of the several dwarf dinosaurs that decreased their size to survive in the islets of the Late Cretaceous Europe. Even though small, the struthiosaur was very well-protected, with a very complex armor reminescent of that of an american nodosaurid; today, scientists classify it in its own nodosaurid subgroup, the Struthiosaurines. Struthiosaurus makes also a striking example of I Have Many Names: its remains, found in several European places, among them Transilvania, were once classified in more than six genera ("Danubiosaurus" and "Crataeomus" among the others). A recent found among european ankies (2005) is Hungarosaurus from Hungary: another inhabitant of the Late Cretaceous islets but bigger than Struthiosaurus, it was the most complete European ankylosaur until the discovery in Spain of the Early Cretaceous Europelta ("european armor"), made in 2013.

Jurassic North-American Tank: Mymoorapelta

  • In the 1990s, the classic “nodosaurid” / “ankylosaurid” bipartition falled down: many nodosaurids revealed not to be so-closely related with Sauropelta or Edmontonia (which, together with their closest relatives, make the Nodosaurines); among them, the “Polacanthines” or "Polacanthids" group was created to include the European Polacanthus and the North American Hoplitosaurus ("soldier lizard"), known since the start of the XX century from scanty remains. Just in the 1990s new, more complete polacanthines or polacanthine-relatives were found in USA. The first one, following the trend to name ankylosaurs with –pelta, was called Mymoorapelta in 1993: this one was the first North American ankylosaur from Jurassic, and lived alongside Stegosaurus Allosaurus Diplodocus etc., but today is considered too primitive to be a real polacanthine.

Gargoyle Dinosaur: Gargoyleosaurus

  • Also from the same Late Jurassic North-American fauna was Gargoyleosaurus ("Gargoyle lizard"), found in 1998, more closerly related with the polacanthines than Mymoorapelta. Aletopelta and Cedarpelta, both found in the early 2000s, lived in the Cretaceous North America, and are considered primitive ankylosaurids but sharing also resemblances with polacanthines, leading some thinking the latter were closer to club-tailed ankylosaurs than to proper nodosaurs. A striking near-polacanthine nodosaur was described in the same year of Gargoyleosaurus, but comes from Early Cretaceous, the Utahraptor age: Gastonia. Still another ankylosaur with the name ending in -a. Indeed this is the dino group with the greatest number of names ending so, giving them a bizarre “feminine” sound for these bulky “tanks”. Found in 1998 as well, Gastonia was clubless and medium-sized for an ankylosaur, but impressed researchers because of its armor, filled with long spikes pointing to all directions. Some people have hailed it as the most armored animal ever existed on Earth: in short, a perfect opponent for the neighboring Utahraptor. Indeed, Gastonia fights the giant dromeosaurid in the Jurassic Fight Club, and ends the battle as the victory.

Ascended Fanon to an Extreme: Tianchiasaurus

  • Among the ankylosaurs the most awesome case regarding naming questions comes from Jurassic China: “Jurassosaurus nedegoapeferima”. Found in the early 1990s (when the Jurassic Park-mania began), the name was proposed by Spielberg himself, but chinese scientist Dong Zhiming (one of the three dino-experts who found the famed young Pinacosaurus dead together in Mongolia few years before) discarded it, officially naming the animal Tianchiasaurus nedegoapeferima (other discarded synonyms of it were "Tenchisaurus", "Tianchisaurus", and "Sangonghesaurus"). The long, bizarre species name is formed from the surnames of the film's main stars: Sam Neill, Laura Dern, Jeff Goldblum, Sir Richard Attenborough, Bob Peck, Martin Ferrero, Ariana Richards, and Joseph Mazzello. And another asian ankylosaur was in 2002 named Crichtonsaurus for Michael Crichton. Well, ankylosaurs really have some of the most awesome names within the dinosaur world.