Polacanthus Reconstruction: Part 11 ‘Caudal Spines’

Previously I wrote about sculpting a pair of the enigmatic ‘Splate’ spines. Something I will be returning to later. With a pair of Polacanthine Splates finished, the next job was to sculpt all the spines of the tail.

Based on a couple of different interpretations I needed to sculpt between 22-24 Caudal Spines, now that’s a lot of spines! Fortunately they get smaller towards the end the tail.

Unlike the ‘Splate’ I do have a cast of an (early to middle) tail spine to refer too. So I measured the spine and drew it at just over half scale to make a template.

With the outline marked on the extruded polystyrene I cut the shape out and started to carve the spine.

Once the first spine was finished I carved the other spine of the pair.

With the first pair of Caudal Spines finished I repeated the process by sculpting the second pair of spines (using the first pair as an example).

At the end of the day I took a group shot of all the pairs of spines (Cervical - Pectoral, to Caudal) sculpted to date.

Next time I will complete the process of sculpting the remaining Caudal Spines.

Polacanthus Reconstruction: Part 4 ‘We can rebuild it….’

With Christmas and the New Year celebrations over for another year, the priority was to make a start on turning the Minmi model into a Polacanthus.

The modifications required include:

• A new head - based on Gastonia burgei.
• A number of spines and plates over the body and the tail.
• A Sacral Shield over the hips.

I went through my scientific papers on Polacanthus, Gastonia and their relatives to refresh my memory before putting pen to paper. Gastonia has the most complete skeleton of a Polacanthus relative and there are several mounted Gastonia skeletons on display in the United States. The first mounted skeleton was produced by Robert Gaston, Jennifer Schellenbach and James Kirkland (2001) in the Armoured Dinosaurs. They arranged the spines based on the best information available, so I decided to use this as the starting point of my attempt to reconstruct a Polacanthus.

The first thing to do was plan out the arrangement of the spines, scutes, the sacral shield and label them; this would allow me to break the task into ‘bite’ sized chunks.

Over forty spines, a fleshed skull and a sacral shield would need to be sculpted. So I would have my work cut out to get it ready in time for the end of March.

With time ticking the next task was to set-up a workshop space with everything required in easy reach.

Before starting to carve the spines I requisitioned the Children’s area (which explains the Dinosaur pictures on the walls), relocated the Minmi, set-up my drawing table, a heater and stuck my laminated inspirational pictures to the wall. With my Palaeontological Fortress of Solitude complete I was ready to get to work.

Polacanthus Reconstruction: Part 3 ‘The best laid plans…..’

The Minimi model made a great impression on the visitors to the Dinosaur Expeditions Centre as it helped to give the Wealden Floodplain diorama some context and scale. During guided tours we explained that it was a work-in-progress and pointed out what we were planning to add to the display.

The centre closed to the public at the end of the main tourism season in November 2013. The priority was to continue work on the Brachiosaur ‘Barn-sized Sauropod skeleton’. Unfortunately the time flew by and we couldn’t mount all of the newly sculpted bones before we had to stop and re-open for the start of the 2014 tourism season. Knowing that once the initial rush of the Spring holidays ebbed away the centre would be quiet for several weeks I had an idea!

The Minmi needed modifications to change it into a Polacanthus. The head was the wrong shape and lacking in certain details, the body and tail needed spines and the sacral shield over the hips needed enhancing. If the Minmi’s head was removed I could sculpt the modifications required to finish the head, add suitable taxidermy eyes and then reattach it back on to the body before the Summer Holidays. After discussing it with my fellow Directors and assuring them the work would be done with plenty of time to spare the decision was made to saw the head off!

It was a relatively simple to remove the Minmi’s head and drill-out the eyes. I had sourced some milliput from a local art shop and set-up a tray for the Dinosaur head, sculpting tools and materials. I made initial progress, but every time I started sculpting the phone would ring, or visitors would arrive and I would have to stop. I soon realised that not only was the sculpting material not delivering the result I wanted but I wasn’t going to finish the job in time for the Summer Holidays.

One of our visitors, Andre (a professional model sculptor) made recommendations on a different type of  sculpting material and I came-up with a new plan. Rather than bulk out the head to match the shape of a different dinosaur, it would be easier to put ‘flesh’ on a cast of the skull. The finished result would much more life-like but it would cost a lot more.

However before going to Plan B, I would have to explain to the other Directors what had gone wrong and that the cost of the job would go up significantly. Fortunately they were very understanding given the circumstances. However it was decided that we would have to wait until the end of the tourism season to ensure we could afford to order a cast of the skull and the professional sculpting material that would form the finished head.

In the meantime there was a headless Minmi / Polacanthus on the diorama, so I improvised by reusing part of the original cardboard packaging and a marker pen to produce a cardboard head. 

This provoked a lot of comment by visitors wondering what had happened to the dinosaur’s head? In some ways it became a feature of our guided tours of the centre in 2014 and it certainly engaged children and adults alike with the ‘reveal’ when the cardboard head was removed!

As the 2014 tourism season drew to a close, my attention returned to the forlorn looking dinosaur on the diorama and I resolved to get it finished over the coming winter.

Polacanthus Reconstruction: Part 2 ‘Careful what you wish for….’

In 2010 a local fossil collector Kai Bailey discovered some Polacanthus bones. A section of the sacral shield, an ilium (hip bone) a sacral (hip) vertebra and some scutes (bone armour in the skin). Later he discovered a large spike and a large lump of bone. In 2013 he approached Dinosaur Expeditions C.I.C. and generously offered to loan us this Polacanthus material to go on display at the newly created Dinosaur Expeditions Centre. Needless to say I was ‘over-the-moon’ about having Polacanthus material in close accessible proximity and couldn’t get the loan form signed quick enough!

We placed the material in one of the largest display cabinets which formed a core part of our Isle of Wight Dinosaur bone exhibition. The cabinet was directly opposite our diorama of the Wealden floodplain; a  representation of the environment in the Lower Cretaceous with a large painting produced for us by internationally renowned palaeoartist John Sibbick. The landscape was a work-in-progress with vegetation but no dinosaurs. Several suggestions had been made but as a start-up Community Interest Company we couldn’t afford to commission a model or purchase a fibreglass dinosaur.

                      

We searched the internet and discovered Jolly Roger Limited, a UK based supplier of Fibreglass models. After browsing their website several possibilities presented themselves. None of them would be ideal representations of local dinosaurs without some modification. Given our experience in building a ‘Barn sized Sauropod skeleton’ this additional work shouldn’t present a barrier to getting the result we wanted.

Within a couple of months of operating we had saved enough to purchase a single dinosaur and have it shipped before the Summer Holidays began. After careful consideration the Directors decided that the Minmi model seemed to be the best option with a small crocodile added for good measure. The Minmi looked good in its original condition and would require less work to complete the transformation into a Polacanthus than turning a Utahraptor into an Eotyrannus!

A couple of weeks later we were in possession of a Minmi model which seemed almost made to measure when we mounted it on the Wealden floodplain diorama, just in time for the Summer Holidays.

Polacanthus Reconstruction: Part 1 ‘Imagination + Wishful Thinking =……’

Royal Mail Stamp: Polacathus by John Sibbick

Introduction:

I have to confess I really like Polacanthus foxi. My infatuation started 20 years ago. I was a teenage volunteer at the Dinosaur Farm and in the intoxicating vapours from acetone (used to clean and repair the ‘Barnes High Sauropod’) on a warm sunny day, the volunteers were all deep in conversation about our favourite dinosaurs.

Now our ‘local’ dinosaurs weren’t the household names of A-list celebrity dinosaurs that trip off the tongue;  T.rex, Triceratops, Stegosaurus, Diplodocus and even Velociraptor (newly elevated to cult status due to the success of the Jurassic Park movie). We had the old school dinosaurs of Iguanodon, Hypsilophodon, and Polacanthus and predators including a Theropod referred to as Megalosaurus (but identified as Neovenator in 1996), the fish-eating Baryonyx, and Aristosuchus, Calamosaurus, Calamospondylus, Ornithodesmus (later identified as the Pterosaur Istiodactylus in 2001) and Thecocoelurus (a number of assorted small Theropods known from a hand full of bones).

I honestly didn’t have a favourite. Sure I could repeat the well trod names of famous Theropods but I didn’t have an emotional response to these dinosaurs other than the ‘coolness’ associated with them. As wannabe palaeontologists we talked about what we wanted to specialise in when we ‘qualified’ with all the naivety that comes with [Imagination + Wishful Thinking = Talking Nonsense]. It seemed that everyone wanted to research Theropods. I realised that if I was going to become a Palaeontologist I would need to broaden my interest as very few Palaeontologists exclusively specialise in Theropods, there isn’t enough of them (never mind the lack of fossil bones due to their relative rarity) to go around!

So I thought about the options and in the end I realised that there wasn’t much interest in Polacanthus.  It looked like a giant sheep with a shield over its hips, covered in spikes. It might not have the ‘coolness’ associated with Theropods, the sheer mass of a Sauropod or the relative abundance of the Ornithopods Iguanodon and Hypsilophodon but it held its own in the Wealden floodplain of the Lower Cretaceous 125 million years ago and deserved respect.

Over the next few years I had read everything written about it, visited the collections of Polacanthus material held in the bowels of the Natural History Museum in London (BMNH), the Museum of Isle of Wight Geology and even a privately owned specimen known as ‘Spike’. My infatuation was complete save for the fact I had never found a piece of Polacanthus on the beach.