Current projects

Been a while since I posted anything here.
Still busy with our upcoming website, but in the meantime we have been working on a couple of really interesting projects, which are almost completed now, but I'll just post some early pictures for now.

We have been asked to clean a full shark and skate skeletons for a french natural history museum. This is a really exciting opportunity, and they look fantastic so far. The species are a school shark (Galeorhinus galeus) and undulate ray (Raja undulata). Both are male specimens caught off the coast of Brittany in France. The plan is to have them displayed next to their taxidermied versions, which were recently completed by Bernard Bourles, an excellent ichthyotaxidermist (his website can be found here: http://www.poissons.net/).

Galeorhinus galeus. This specimen is a male around 1.20 m long.

Dissection of the gills, this part needs to be done very carefully as not to damage the delicate branchial rays and extrabranchials, which are visible on top of the gills here.

Raja undulata, male specimen as well. This is the largest skate I've been working on so far.

As with most skate, many parts of the body are covered with various kind of spines and thorns. These are located on the pectoral fins and make handling such a specimen a bit tricky as they are extremely sharp.

The tail is also covered with them.

Massive jaw musculature.

A couple of other projects we're currently working on is another full shark skeleton for a british aquaria, which should be completed very soon, and a few other critters as well, of which the most impressive is certainly this bowmouth guitarfish.

It's a small specimen that died in captivity. It's in good condition overall despite several issues with the skeleton, and shows some truly incredible morphological features.

Detail of the dentition. While many species have funky teeth, this species has always striked me as one of the most incredible chondrichthyan dentition.

Top view of the neurocranium during preparation. The cartilage was a bit damaged in the rostral area, but once again, really impressive thing. It's massive, and really looks like some bizarre hammerhead shark.

That's it for now, pictures of the finished specimens will follow soon!

Portuguese fish!

A few weeks ago I attended the 4th IAFSB (Interdisciplinary Approaches in Fish Skeletal Biology) meeting in Tavira, Portugal. I had a fantastic time there with great science and great people, and it came as a very nice surprise to see so many shark people there.

A few of us also took the opportunity to go to the local fish market see if we could find some cool fish to take home, which was really funny because for once I was not the only weirdo looking for heads or strange species. We saw loads of black and silver scabbardfishes and really wish I had gotten some of these, but I was already loaded with the cartilaginous stuff. Here's a few pictures of the specimens I brought back.

Torpedo sp. and Mustelus mustelus (? could be M. asterias, not quite sure on this one).

The torpedo skull on the left is very damaged: the fishermen cut through the jaws, one hyomandibular, and they also damaged the nose area (the antorbital cartilages are entirely missing). I still took it since it's the first time I come across torpedoes and it should still be useful as a practice specimen since I'm not very familiar with their skeletal anatomy.

 Couple of skates. The big one on the left is Raja microocelata and still have to ID the two smaller ones, probably Leucoraja something.

 

Unidentified torpedo head (T. marmorata or T. torpedo) and whole T. torpedo. 

The head is either from T. marmorata or T. torpedo. The first specimen had already been skinned and cut in pieces so ID is difficult, and they had both species at the market. The atlantic torpedo (Tetronarce nobiliana) is also present in the area, but this species is much bigger and usually found at greater depths. The complete specimen should make a very cool skeleton, unfortunately the pelvic fins are a little damaged.

Dissection time!

Photo: Callie Crawford

Since none of us planned to be working on fresh specimens we had to improvise a bit. I had to buy several kilos of salt to prep them for the return trip. The other guys used some kind of cheap vodka and big plastic jars for their stuff. Wish I had a picture of this since it was quite funny. But the best part was trying to dissect fish using a table knife and nail clipper. Not the easiest way to do it!

Busted torpedo skull close up.

Photo: Callie Crawford

Everything is now safely stored in the freezer. I'll post WIP pictures here as I get around working on them.

Clearing and staining

For the past months I've been playing around with this kind of stuff:

 Juvenile cornsnake (Pantherophis guttatus) that was cleared and stained last year. The Alcian blue excess was not completely removed by the KOH and we probably didn't use enough alizarin.

This is called clearing and staining, and a quick google search will provide you with loads of really cool pictures, and an equally large amount of protocols so you can try out this technique by yourself.
Basically, most protocols are derived from Dingerkus and Uhler (1977), although this technique is much older than that, and much details can be found in "Clearing and staining skeletons of small vertebrates", by Davis, Gore & Osgood, and which is available here.
Basically, tissues undergo an enzymatic digestion using trypsin. This is the clearing stage. Then the specimen is double stained, first using Alcian blue, which stains cartilage blue, then with Alizarin red, which stains bone a deep red colour. Specimens are then stored in a glycerin solution, which has an index of refraction very close to that of collagen, which helps "transparize" the specimen further.

In addition to looking truly beautiful, this is a very useful technique in biology, still widely in use today. It allows the study of the skeleton of very small vertebrates without the need for "classical" osteological preparations, which are especially problematic with this kind of material. It also routinely used for the study of ontogenetic patterns of ossification, along with more modern techniques such as X-ray microtomography. A third staining agent, Sudan black  B is also sometimes used as a nerve stain on previously cleared and double-stained specimens.

While on the subject, check out these specimens, cleared and stained by Adam Summers:
Some really cool fish

A friend of mine recently sent me a sample of a product called visikol, which is basically a clearing agent used for microscopy. I've yet to give it a try (which I should do very soon), but I've seen some very interesting preliminary results. It seems to clear the specimens very quickly, the tricky part being the staining process. Will probably post the results over here when I start experimenting with it.

Juvenile black scorpionfish (Scorpaena porcus) recently finished. This one took didn't clear well, probably due to the improper use of trypsin. However the stains worked quite well. Notice how the scales are deeply stained by the Alizarin red.

Close up on the jaw of a juvenile skate (Raja sp.). The tesserae are clearly visible

Reference:
Dingerkus G, Uhler L. 1977. Enzyme clearing of alcian blue stained whole small vertebrates for demonstration of cartilage. Stain Technology, 52: 229-232.

Happy new year!

Happy new year! Currently away and not doing any natural history related work, but here's a quick picture of a cleaned juvenile skate (Raja sp.) skeleton. The gills could not be saved on this specimen due to its small size and great fragility.

Juvenile Raja sp. complete skeleton. The neurocranium is about 3 cm long only.

Sharks, skates and fish heads

Quick update on the smooth-hound shark of the first post. Part of the skeleton is now clean and drying.

Here is a quick labelled picture with some cleaned parts. The fins are dried between clear acrylic sheets to keep them flat. 

I still have to clean most of the fins, the jaws, and of course the branchial apparatus which is the most delicate and fragile part of this kind of skeleton. Will post updates on this later.
Also completed a couple of skate (Raja asterias here) skulls for some friends. Just shipped these three to the Netherlands.

Two female and one male skulls of R. asterias. Note that the specimen on the right is missing the labial cartilages, which is due to the way the specimen was handled at the fish shop.

Currently working with a lot of small chondrichtyan, so I'll probably make a post about cartilaginous skull cleaning sometimes soon.

Other things include a recently cleaned european hake (Merluccius merluccius). This is just to show how a macerated (and degreased and whitened) fish skull looks like. These are pretty straightforward to reconstruct, and should look like this when finished:

European hake skull (M. merluccius) macerated (top) and reconstructed (bottom). Note that I made a mistake with the upper jaw, which should be positioned higher, in direct continuity of the tip of the neurocranium.

And finally, on my regular visit to a nearby fish shop, I was extremely excited to find this fish:

Fresh (and tasty!) atlantic stargazer (Uranoscopus scaber).

It's a stargazer, named after its upward looking eyes. This is a really cool fish for several reasons: they are venomous (they sport a couple of nasty spines in the opercular region, one is visible in the picture, just above the right pectoral fin), and are capable of bioelectrogenesis (ie is capable of generating electricity, just like the electric eel and the electric ray). They also possess an incredibly armored skull, just like on this picture:

U. scaber skull. This skull is in my collection, but was not cleaned by me. The venomous spines are clearly visible.

And on top of that, they taste really nice. Also got a black scorpionfish (Scorpaena porcus), greater weever (Trachinus draco) and a sea robin (still have to look up the proper ID for this one) along with the stargazer, and they should all make great specimens once cleaned.