Volunteers’ Week: What is a dinosaur?

This week Manchester Museum, along with hundreds of museums, galleries, societies and institutions across the country, is celebrating Volunteers’ Week.

“Volunteers’ Week is an annual event which celebrates the fantastic contribution that millions of volunteers make across the UK. The week plays a huge part in raising the profile of the millions of volunteers who regularly contribute to society, while inspiring others to get involved too.” – volunteersweek.org


Manchester Museum is a great place to volunteer with many different opportunities and programmes. Every day the museum’s collection is brought to life by volunteers on the object handling tables throughout the museum. As part of our #volunteersweek celebrations, this week’s story from the museum floor is a guest post by Sarah who volunteers with the palaeontology collection.

For more about Palaeontology, please visit the Curator’s blogPalaeo Manchester.


What is a dinosaur?

I volunteer on the palaeontology handling table at Manchester Museum, and although a little dinosaur-obsessed as a child – I still have a collection of Natural History Museum plastic dinosaurs decorating my window ledge and a Brachiosaurus in the bathroom – I am not a palaeontologist.

What I do know is an Ichthyosaur is not a dinosaur!

imageIchthyosaur (Stenopterygius acutirostris). L.1688, Fossils gallery, Manchester Museum.

My volunteer training taught me this, and for most children (and adults) who come to the handling table and ask if the Ichthyosaur vertebra is from a dinosaur, my answer, “It is an aquatic reptile that lived at the same time as the dinosaurs, so technically it is not a dinosaur, but it is pretty close” is met with general acceptance.

I had been volunteering for nearly a year when someone asked, “What is a dinosaur?”


The idea of dinosaurs has for a long time been a part of the popular imagination, encompassing all sorts of prehistoric life, including creatures that are and are not dinosaurs. (Image from: manchestereveningnews.co.uk)

A dinosaur is… a dinosaur! Everyone knows what a dinosaur is… or do they? And why isn’t an Ichthyosaur a dinosaur?

First stop Wikipedia, always a good start for an easy answer!

So, dinosaurs are part of a clade called ‘Dinosauria’, a clade being “a group of organisms that have evolved from a common ancestor” (OED, 2016) – I have read one line and I already need a dictionary (or perhaps a thesaurus!), maybe Wikipedia is a little too advanced – I figure what I need is ‘Dinosaurs for Dummies’, so here goes with my version…

In 1842 palaeontologist Sir Richard Owen coined the term “dinosaur” from the Greek δεινός (deinos) meaning “terrible” and σαῦρος (sauros) meaning “lizard” to describe a “distinct tribe or sub-order of Saurian Reptiles”. Although dinosaurs were only classified fairly recently their fossils have been known about for thousands of years. The Chinese believed dinosaur fossils to be dragons’ bones. The modern Chinese term for dinosaurs still reflects this identification; 恐龍 (kǒnglóng), “terrible dragon”.


Sir Richard Owen (1804-1892). Image from: nhm.ac.uk

The ‘Scientific Revolution’ of the early-modern period and subsequent theories of evolution unsurprisingly led to increasing interest in fossilised remains. Academic study of dinosaur bones began in 1676 when Robert Plot, Professor of Chemistry at Oxford and curator at the Ashmolean Museum was sent a fossilised femur (of a Megalosaurus). Plot recognised the bone was from an animal larger than any previously known, however contemporary religious narratives led to its identification as that of a (biblical) giant.

The first dinosaur species to be named came in 1699 when Edward Lhuyd identified a sauropod tooth as belonging to a creature which he named Rutellum (this name is no longer in use). Through the 18th and 19th centuries more species were discovered leading to their classification as “Dinosauria” in 1842.

Currently over 1000 species of dinosaur have been identified, but what actually are they? How can we define a dinosaur?

Dinosaurs are terrestrial reptiles (so ichthyosaurs can’t be dinosaurs!), first appearing approximately 230 million years ago during the Triassic Period. They are the most successful group of animals in terms of longevity. Early scientists believed that rather there were two or three distinct groups which evolved independently, however modern palaeontologists have devised a shared set of features which identify dinosaurs; characteristics that are present in all dinosaurs, but importantly are not in other animals, suggesting inheritance from one common ancestor. These include:


Massospondylus Skull Steveoc 86.pngImage from: Steveoc 86Own work, CC BY 3.0, commons.wikimedia.org

Two holes behind the eye socket and one hole between the eye socket and nostril, and the bones at the back of the skull do not meet along the midline of the cranial cavity.


Carnotaurus LA.jpg
Image by Julian FongCarnatosaurus, uploaded by FunkMonk, CC BY-SA 2.0, available from: commons.wikimedia.org

There are bony projections on the cervical vertebrae (the atlas and axis vertebrae in the neck).


The radius is less than 80% of the length of the humerus.


The hip is constructed of three bones (the ischium, the ilium and the pubis) which are separated by hole where the femur attaches.

Types of dinosaur pelvis. (Image from: britannica.com)

There is a projection of the rear inner femur that the tail muscle attaches to.

The fibula is less than 30% of the width of the bones of the upper ankle allowing the dinosaur to stand on its hind legs.

Just a couple of hours of research resulted in a somewhat basic understanding of what makes a dinosaur, well, a dinosaur! And has inevitably led to more questions than answers but I am now looking forward to the next person who comes to the handling table and asks, “what is a dinosaur?”

Sarah Scott

Find out more:

For more about Palaeontology, please visit the Curator’s blogPalaeo Manchester.

And read more about our volunteer and community programmes:
Climate Control: Marvellous Moths
Talk English – Birds and Butterflies
Museum Inspires Pictures at an Exhibition
IF Volunteering
Venture Arts Venture Out


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