What Dinosaur has the Longest Name?

There is a village in Wales with the longest name in the UK (Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, in case you were wondering), with a massive 58 letters. And, not easy to say if you aren’t Welsh!

Dinosaurs are also known for their long names, and for being tricky to pronounce, in fact, the longest name has a tongue-twisting 23 letters, but isn’t so hard to pronounce if you know how!

Micropachycephalosaurus (said my-crow-pack-ee-seff-ah-low-sore-us, from the Greek, micro – tiny, pachy – thick, cephalo – head, saura – lizards) is made up of a grand total of 23 letters and 9 syllables, and is the longest dinosaur name of them all to date. The Micropachycephalosaurus itself, however, was not quite so impressive. Around 0.8m tall and 0.6m long, these dinky dinosaurs have a name which actually means ‘small thick-headed lizard’, and are indeed one of the smallest dinosaurs discovered. However, ‘thick-headed’ may not necessarily be the best description for it; read more fascinating facts about Micropachycephalosaurus to find out why.

An artist's impression of the Micropachycephalosaurus. A tiny dinosaur with the longest name.
An artist’s impression of the Micropachycephalosaurus. Credit: Unknown.

What Other Dinosaurs Have Long Names?

Research has shown that Micropachycephalosaurus was very similar in appearance to Pachycephalosaurus, made famous for bulldozing anything in its path in the Jurassic World films, but much, much smaller! So, although not the most well-known dinosaur, Micropachycephalosaurus was given greatness with the title of being the dinosaur with the longest name. But what other dinosaurs are fighting for the honour of having the longest dinosaur name in history? Let’s find out!


A reconstruction of the skull of a Carcharodontosaurus dinosaur. It's large with huge teeth that were up to 30cm long.
A reconstruction of a Carcharodontosaurus skull, from the Science Museum of Minnesota.

A strong contender for the title of the longest named dinosaur is the mighty Carcharodontosaurus (said car-car-oh-don-toe-sore-us). Consisting of a staggering 19 letters or characters and 7 syllables, this second longest dinosaur name comes from the Greek for the genus of sharks, Carcharodon, and was renamed by fossil hunter, Ernst Stromer von Reichenbach in 1931.

Due to the long, jagged teeth of this huge, carnivorous dinosaur, he named it ‘shark tooth lizard’, or Carcharodontosaurus, giving it the second longest dinosaur name ever known. Although its name is 4 characters shorter than Micropachycephalosaurus, Carcharodontosaurus was anything but short. Its teeth were up to 30cm long and it could be as tall as 13ft. Also, after the original fossils were destroyed by bombing in World War II, a new fossil skeleton of this biped beast was found in 1996 and, at 44ft long and weighing nearly 8 tons, was even larger than the previous find.

Carcharodontosaurus could well have been bigger than the terrifying T-Rex and was, without doubt, the apex predator of the mid-Cretaceous period in Northern Africa. As fossils of other predators such as Spinosaurs have been found in the same areas, it is possible that Carcharodontosaurus fought for its territory with other fearsome giants of the dinosaur world and, quite probably, lived up to its station as the dinosaur with the second longest name in history.


A 3D render of a Archaeornithomimus, which is a bird-like dinosaur.
A 3D render of a Archaeornithomimus, the dinosaur with the 3rd longest name.

Archaeornithomimus (said ar-key-or-nith-oh-meem-us) is the third longest dinosaur name at 18 characters and 7 syllables, and is comprised of Greek words meaning ‘ancient bird mimic’. These fearsome theropods (they had hollow bones just like birds) were hunting the wilds of China, Uzbekistan and Mongolia in predatory packs some 95-70 million years, during the late Cretaceous period. Standing at around 1.5m tall and 3.3m long, the Archaeornithomimus has 5 less characters and 2 less syllables in its name than Micropachycephalosaurus, but could easily win the prize for the hardest name to pronounce!

Being the dinosaur with the third longest name is a lot to live up to, and Archaeornithomimus did try its hardest. It had extremely strong legs and could easily outrun the slower, bigger predators living in its environment. It probably lived in small herds with others of its kind for safety and, scientists believe that, due to evidence collected from other close relations in the ornithomimosaurian genus, Archaeornithomimus actually had feathers. In addition, it’s thought that it was not strictly a herbivore (meaning it only ate plates), instead it’s been suggested that small mammals and insects may also have been part of its diet. This makes it an omnivore, which means that just like everyday dogs and cats, it was happy to eat either meat or plants.

For a good idea of how an Archaeornithomimus would look and move in real life, its close relative, the Gallimimus, has a starring role in the original Jurassic Park movie and can be seen thundering across fields and valleys in herds, just like present day wildebeest on the African plains.


A graphic highlighting the size of a Pachycephalosaurus in comparison to a human.
A graphic highlighting the size of the Pachycephalosaurus in comparison to the average human.

The fourth longest dinosaur name belongs to the previously mentioned Pachycephalosaurus (said pack-ee-seff-ah-low-sore-us). This dense headed dinosaur also has 18 letters and 7 syllables in its name and was first discovered in the 1830’s in present day Montana, USA. Its name means ‘thick headed lizard’ in Greek, and it is characterised by a thick, dome-shaped skull which some palaeontologists believe was used for butting heads with any rivals in its herd. This is just one theory though, and as there have been no remains other than skulls discovered, scientists have used a lot of guess work to come up with Pachycephalosaurus facts.

Research has shown that Pachycephalosaurus lived 65-100 million years ago, during the late Cretaceous Period, in North America and Canada.  Its skull was up to 10 inches thick and scientists believe that it could have grown up to 15ft long.  Initially, this bony headed beast was thought to be a herbivore but, more recently discovered fossils which were named as Stygimoloch and Dracorex, are now thought to be juvenile Pachycephalosaurus.  Although they do not have the dome-shaped skull, they do have small teeth, which has led dinosaur hunters to believe that meat may well have been on the menu for these junior juggernauts too.


An artist's impression of the Eustreptospondylus dinosaur. It's ferocious looking with small red horns above its eyes.
The Eustreptospondylus, the dinosaur with the 5th longest name.

And finally, with a respectable fifth longest dinosaur name, with 18 characters and 6 syllables, is Eustreptospondylus. Said ‘you-strep-toe-spon-dee-luss’, the name means ‘true well-curved vertebrae’ in Ancient Greek, and was given to the fossil skeleton first discovered in 1870 in a brick pit close to the city of Oxford in the UK. It was renamed and reclassified with its own genus in 1964, and should rightly be far more well-known than it is due to its immense size, ferociousness, and the fact that it was, and still is, the largest Jurassic European theropod skeleton ever discovered.

Eustreptospondylus did have its profile raised when it became a star character in the BBC series, Walking with Dinosaurs. Viewers were able to get further insight into the life of this carnivorous giant when it lived, 165 million years ago. Weighing in at nearly 2 tons and growing up to 30ft long, like all theropods, Eustreptospondylus had 3 toes and claws on each limb, with its fore limbs being short, while its hind legs were muscular and powerful. Scientists have proposed that these stubby arms did not hinder it in any way, in fact, they think that Eustreptospondylus could actually swim. And this could well be the case; Eustreptospondylus lived along the shores of southern England which, during the Mesozoic Era, were made up of a number of small islands. To venture further afield for food or a mate, there were no other options than to take a dip!

Fascinating Facts about Micropachycephalosaurus

An artist’s impression of the Micropachycephalosaurus dinosaur, the dinosaur with the longest name.
  • It really was very small. Weighing in at around 8lbs, standing from 30cm tall and just 3ft long, Micropachycephalosaurus is included in the list of the smallest dinosaurs discovered in history.
  • It lived 80-70 million years ago, during the late Cretaceous era, and would have been a common sight in the woodland areas of Asia.
  • Micropachycephalosaurus was a herbivore and probably ate seeds, berries and plants.
  • It probably lived in flocks, with large numbers of relations close by, and was a fast runner to escape from the numerous predators who wanted it for lunch.
  • Palaeontologists think that Micropachycephalosaurs had skin colours which gave them excellent camouflage.  Research suggests that it was yellowy-green, a froggy kind of colour, and probably had white stripes along its body and tail, giving it a good chance of escape into long grass or forest when a predator, such as Microraptor, was around.
  • It is not actually related to Pachycephalosaurus at all.  When Micropachycephalosaurus was first discovered by famous fossil hunter, Dong Zhiming in Eastern China in 1972, he decided that it would be classified as a pachycephalosaur.  However, further research in 2006 showed that there was no evidence that this diddy dinosaur was related to Pachycephalosaurus.  To complicate things further, the skull from the original remains was missing from the collection in China leading to more questions on its ancestry. 
  • Micropachycephalosaurus may actually be part of the triceratops family.  Recent research on the incomplete skeleton has shown that it is more similar to Ceratopsian dinosaurs such as the titanic Triceratops.  In this case, it was a very small horned, or frilled, Ceratopsian, but can still claim this amazing ancestry!

So, now you know more about the magnificent Micropachycephalosaurus maybe you can decide what type of dinosaur you think it is. Whatever the result, for now Micropachycephalosaurus is still reigning champ when it comes to multisyllabic monikers. But, depending on further research and discoveries, it just may not always have the longest dinosaur name of them all.

Longest Named Dinosaur FAQs

What dinosaur has the longest name?

The Microcephalosaurus has the longest name, with 23 characters and 9 syllables.

What dinosaur has the second longest name?

Carcharodontosaurus, with 19 characters and 7 syllables.

What dinosaur has the third longest name?

Archaeornithomimus, with 18 characters and 7 syllables.

What dinosaur has the fourth longest name?

Pachycephalosaurus, with 18 letters and 7 syllables in its name.


  • NHM.ac.uk
  • NewDinosaurs.com
  • Prehistoric-wildlife.com
  • Thoughtco.com
  • Charactercounter.com
  • Dinosaurfactsforkids.com