Tag Archives for skull

Friday mystery object #224

For the last few weeks I’ve been using cat skulls as mystery objects, because they are really hard to tell apart and I was hoping that some useful distinguishing features might get spotted when you try to identify them.

I certainly feel like I’ve learned something, but I’m pleased to say that there aren’t too many more skulls to go, because it’s really difficult. This next one should hopefully be a bit easier than some of the recent cats:

mystery224

Any idea what fine felid this skull comes from?

As usual I would really appreciate your thoughts in the comments section below – let’s see if we can crack this!

Friday mystery object #223 answer

Last Friday I gave you this fine feline to have a go at identifying:

mystery223

I was a little suspicious of the identification attached to the specimen, but Al Klein suggested the same species – the Jaguarundi Puma yagouaroundi (É. Geoffroy Saint-Hilaire, 1803) [link opens pdf].

My reasons for suspicion were the nature of the post-orbital constriction (the narrowing of the braincase behind the eyes), the nature of the zygomaticotemporal suture between the temporal process of the zygomatic and the zygomatic process of the temporal bone (the bit where two bones meet to make the arch of the cheek) and the shape of the nasal bones where they meet the frontals (the V shaped bones above the nose area).

The observation by henstridgesj that the skull was similar to the previous mystery object (Leopardus tigrinus) was a good one, so I decided to research the genus Leopardus in a bit more detail, to see if there was a better match.

It turns out that the skull I found that matched this one most closely – especially with regard to the relative lack of a post-orbital constriction and the nasal-frontal junction – was the highly arboreal Margay Leopardus wiedii (Schinz, 1821) [link opens pdf].

Margay - Leopardus wiedii, Summit Municipal Parque, Panama. By Brian Gratwicke.

I’m always a bit reticent to re-identify specimens that have original labels from the supplier attached as this one does, but this comes from suppliers (Dr.s Schlüter & Mass) that I know have seriously misidentified or mislabelled specimens in the past (e.g. labelling a African Lappet-faced Vulture as an Andean Condor from Bolivia).

Of course, the real identification may be even more complicated, since the South American cats have a bit of a track record for hybridising to the point of masking distinct species, so any identification I make will be laden with disclaimers and caveats. The joy of real-world animals when contrasted against nice simple biological concepts…

Friday mystery object #223

I hope you’re not all fed up with cats yet, because here’s another:

mystery223

I have concerns about the identification attached to this one, so let’s see if your thoughts agree with what I have written on the label.

As always, you can put your thoughts below and they will be very welcome!

Friday mystery object #222 answer

Last Friday I gave you this fabulous feline skull to have a go at identifying:

mystery222

No one got quite the right species, but several people (Crispin, manwhohunts, Maxine and Alex Klein) managed to narrow it down to the correct genus.

The flat frontals give the forehead a slope rather than the usual curve we’ve seen in previous cats of this size, making the cranium appear very domed in contrast. The post orbital processes are quite short and gracile (slender). The jaw is quite short while maxilla bone above the canines appears pinched in and the nasals are steep and protruding somewhat.  These are features that appear in the genus Leopardus – the South and Central American small spotted cats.

How to distinguish between different species of Leopadus is more of a problem. Daniel Jones picked up on the incredibly robust bone margin of the foramen magnum (the hole the spinal chord goes into), which may be distinctive, but so far I’ve not seen the underside of other small Leopardus species skulls, so I can’t be sure.

All I know is that this is the skull of an Oncilla Leopardus tigrinus (Schreber, 1775), a small and mainly ground-hunting South American forest cat. I’ve said it before and I’ll say it again, cats are so difficult to identify!

 

 

Friday mystery object #221 answer

Last Friday I gave you this cat skull to identify:

mystery221

It is about the same size as a Domestic Cat and is very similar in morphology. But it’s not a Domestic Cat. 

The auditory bullae (the bulbs under the skull that hold the hearing apparatus) and the external auditory meatus (ear holes) are a bit bigger, the skull is a bit broader and the interpterygoid notch (the gap at the back of the palate that the airway emerges from) is squarer and has a slight ridge in front of it on the palate (and I’m not sure that ANY of these are particularly significant).

There were plenty of suggestions about what this skull might belong to, but only henstridgesj hit the nail on the head with a correct identification of Southern African Wildcat Felis silvestris cafra Desmarest, 1822. So well done Stephen!

Southern African Wildcat (Felis silvestris cafra) in Kgalagadi Transfrontier Park. Image taken by on Johann du Preez 24 December 2007

Southern African Wildcat (Felis silvestris cafra) by Johann du Preez 2008

Friday mystery object #220 answer

Last week I gave you this lovely skull to identify:

mystery220

As I suspected, everyone immediately recognised it as a type of cat. The characteristic two large blade-like premolars with a gap (diastema) behind the long canines and the straight incisor row were a dead give-away.

Then came the difficult bit. There are around 40 living cat species recognised in the world and because they didn’t diverge from a common ancestor until just 10 million years ago (or thereabouts), they all tend to look quite similar.

There were lots of suggestions, ranging from Lynx to Jungle Cat, but only Jake managed to recognise this short and highly domed skull (with impressively long canines) as belonging to a Marbled Cat Pardofelis marmorata (Martin, 1836).

The Marbled Cat is an tree-dwelling species from South and Southeast Asia that isn’t really very well known. They have a ridiculously long and chunky tail to help with their arboreal lifestyle and beautiful patterns on their coat, which gives them their name.

Photo of a Marbled cat (Pardofelis marmorata) spotted in Danum Valley Conservation Area, Borneo, by Johan Embréus 2009

Since cats are so hard to tell apart do you think I should post a few more over the next few weeks? Between us we may be able to spot some useful distinguishing features…

Friday mystery object #219 answer

On Friday 7th Feb I gave you this mystery skull to identify:

mystery219

The post got lots of activity from both regulars and biology students from the University of Chicago Laboratory School, which means there were lots of helpful comments!

The specimen was quite clearly from a rodent, due to the paired incisors, but there are a LOT of different rodents out there.

The type of rodent was narrowed down by bugblokenz who suggested the skull was from a squirrel of some sort and Jake pointed out how we know that is the case – the specimen has a spiky postorbital process:

rodentpostorbitalprocess

The presence of a spiky postorbital process (see top skull) suggests that it was from a type of squirrel. Most other rodents either lack this process (see bottom skull), or the process is more stout and blunt.

Narrowing it down to a squirrel is helpful, but there are still around 285 different species to choose from and many squirrels have very similar skulls. This is where the real challenge lay, especially since it clearly wasn’t the British Red Squirrel Sciurus vulgaris or the more widespread Eastern Grey Sciurus carolinensis, as I showed you on Friday 14th. Other suggestions included the Southern Flying Squirrel Glaucomys volans (which is a bit on the small side) and Eastern Fox Squirrel Sciurus niger (which has a really interesting method you can use to identify it).

The relatively narrow zygomatic breadth, combined with a relatively wide breadth between the orbits suggests a ground squirrel of some sort, which many people recognised, leading to suggestions of Poliocitellus franklinii, Spermophilus sp., Otospermophilus sp. and Tamias sp. – for which this useful reference provides some great comparative specimens (huge thanks to Crispin for sharing this).

However, none of the North American ground squirrels quite matched up, with the closest suggestions of Otospermophilus variegatus or Poliocitellus franklinii still being different in a variety of ways, particularly in relation to the width of the skull, relative zygomatic breadth and shape of the postorbital process.

After much consideration it came to me that we may be looking on the wrong continent and it turns out that African ground squirrels are more similar to this specimen. Fortunately, there is a very useful resource providing images of specimens of African rodent species available through the Belgian Biodiversity Platform. This fantastic site has enabled me to make a reasonably confident identification of Striped Ground Squirrel Xerus erythropus (Geoffroy Saint-Hilaire, 1803).

Striped Ground Squirrel (Xerus erythropus) by BOISSEL Philippe

Striped Ground Squirrel (Xerus erythropus) by BOISSEL Philippe

I’d still like to get my mystery skull to a comprehensive physical collection, just to make some fine detail checks (there are some issues with the shape of the posterior margin of the palate I’m not 100% happy about), but overall I’m happy with this – but please let me know if you think I’ve missed something!

Big thanks to everyone who has contributed their ideas on this specimen – let’s see what I can find for you to identify this coming Friday…

[Further information available in this species description PDF]

Friday mystery object #219 answer coming soon…

Apologies for not having the answer to last week’s mystery object posted yet – it’s been a busy week and I simply haven’t had a chance to prepare a decent answer.

However, I have an image of last week’s object alongside a Grey Squirrel (the lighter coloured specimen), to give you an idea of how they differ, so I hope that will prove of interest until I can get a proper post prepared:

Grey_Squirrel_vs_Mystery_219

Friday mystery object #218 answer

Last Friday I gave you this skull to identify:

mystery218

There was strong consensus on this being a mustelid – which is good, because that’s what it is. There was also good agreement on it being one of the Martens, which is where things become a bit more difficult.

After looking at a lot of different Marten skulls online without much success in finding a way of telling them apart, this diagram  proved quite helpful.

Images compiled by Mariomassone

Skulls in the sequence: M. zibellina, M. martes, M. foina

If you look at the skull in the middle of the top and centre rows, the auditory bullae (the rounded bones under the skull that house the anatomy used in hearing) have quite distinctive shapes in the three species pictured.

In addition, the the little nub of bone (called the mastoid process) that sticks out behind the ear hole (or external auditory meatus as it’s also known) is very differently developed in the three species. Looking at this character and checking back against other Marten skulls online the clues suggested that the mystery object is the skull of a Pine Marten Martes martes (Linnaeus, 1758).

So well done to everyone who commented – particularly Jake who got the ball rolling with a Martes identification from the start!

Friday mystery object #217 answer

Last Friday I gave you this lovely skull to identify:

mystery217

I chose it because it was being used for an interesting project by a student at UCL, involving 3D surface laser scanning of the specimen to identify landmark characters of the skeletal structure of the faces of this family of primates:

mystery217scan

This is a specimen that we actually have a fair amount of information about. It’s a male Grey Gibbon Hylobates muelleri Martin, 1841 collected before 1909, from Melian on the Hanta River in North Borneo. So of all the suggestions, Crispin (@brainketchup) was the closest (with agreement from henstridgesj) when he suggested White-handed Gibbon.

It turns out that this skull also has a taxidermy skin associated with it (which Jake has mentioned before), which shows a common feature of taxidermy specimens where the skull has been prepared separately – it’s mouth is stitched shut:

GreyGibbon

This makes for slightly dodgy taxidermy, but at least it means the skull is available for future research, instead of being stuck in a specimen intended mainly for display.

The skin of this specimen has also seen recent use, but for art rather than science. Artist Paul Robinson has used it as the basis of this somewhat freaky, but striking piece of work:

GIBBON by Paul Robinson

GIBBON by Paul Robinson

It goes to show that specimens in museums can find themselves being used in all sorts of interesting ways. To my mind this is really what museum collections are for – being used by people.

Friday mystery object #215 answer

Last Friday I gave you this perplexing specimen to identify:

mystery215

It was labelled as a Crab-eating Raccoon, but the facial region is much longer and narrower than other examples I’ve talked about, and it’s much less robust:

Crab-eating Raccoon skull

Now the gracile build could just be because it’s the skull of a juvenile (which is what it looks like), but juveniles have shorter and relatively broader facial regions than adults, so that doesn’t work. Even the less robust jaws of the Common Raccoon are too short and wide for the mystery specimen (which I think may discount Robin Birrrdegg’s suggestion).

Another crab-eating option was suggested by Daniel Jones who thought Crab-eating Fox. Now the overall proportions are a good match for this species, but there’s a problem. If the mystery object had teeth this would be much easier, but there are the holes in the maxilla to give us clues about the shape and size of the molars and as Allen Hazen pointed out:

Three triple-rooted teeth. Are these three molars, or is the last premolar triple-rooted? If it’s three molars… Canids (usually) only have two upper molars…

This is indeed the case and so this skull can’t be from a Crab-eating Fox.

On a different tack, henstridgesj suggested that it might be a civet of some sort, pointing us in the direction of mystery object #143 for comparison:

African Civet skull

But again this really doesn’t look right – in particular the civets have a narrow constriction behind the orbital process, which is lacking in the mystery specimen. This was noticed by henstridgesj and he suggested that the closest option he’d been able to find was a Coati:

Coati skull

Now the specimen of Coati above is a mature male that was mystery object 54 and it doesn’t look much like our most recent mystery object, but on checking the skulls of juvenile and female Coatis I realised that this is probably the best option so far.

I still want to check some more specimens, but I’m really grateful for everyone’s input on this specimen – it’s been a challenge and you have all helped immensely!

I’ll  be back with another mystery object next Friday, but until then I’d like to wish you all a thoroughly enjoyable festive season!

Friday mystery object #215

This week I have a skull for you that I think has been misidentifed, but because its teeth are mostly missing it’s a little hard to be sure.

mystery215

I’d appreciate your thoughts on what it might be and as usual you can put those thoughts in the comments section below. Let’s see if we can work out what this is!

Friday mystery object #214 answer

Apologies for the lateness of the FMO this week, my excuse is a rather apt bout of illness, where some of the alveolar bone of my mandible has been lost due to an infection, leaving me feverish and thoroughly miserable.

But enough about my me, this is the mandible I’m supposed to be talking about:

mystery214

There was a fascinating discussion about the possible identification in the comments last week, so a big ‘thanks!’ to all of the contributors who provided their informative observations (too many to mention everyone by name!). A mustelid of some sort was quickly agreed upon and the general consensus moved towards an otter of some kind, before starting to drift away again.

Two comments in particular were particularly pertinent. The first was from Daniel Jones:

Alright . . . instantly the foramina on the mandible anterior to the premolars scream Otter! However, the incisors don’t. The incisors just lateral to the canines should be larger and longer than any of the other incisors among the otters (even the Asian Short-clawed Otter).

Now my identification for this specimen was indeed Asian Short-clawed Otter Aonyx cinerea (Illiger, 1815), so this comment made me a bit concerned. However, on checking some images online I realised that the long lateral incisors are present in the premaxilla, but not the mandible – an easy detail to miss.

The second comment was by Allen Hazen:

Anyway… The talonid on the first molar of the one in the picture is BIG.

The reason I found this comment useful was that the long and broad talonid (that’s the flatter grinding section on the molar) is what confirmed the Asian Short-clawed otter identification for me (although the small size was a good first clue).  This became quite clear from an image on the Otter Specialist Group webpage.

The Asian Short-clawed Otter presumably has this large talonid because it has a diet mainly composed of crustaceans rather than fish, and it needs the extra crushing area on the molar to crack open tough exoskeletons.

Who would think you’d get teeth as formidable as these on such an adorable little critter?

Geekwars?

After a weekend of discussion about the hashtag #bonegeeks for a crowd-sourced, social media based resource for images of bones, I have come to the conclusion that you can’t please all of the people all of the time.

The nub of the discussion centres on the word ‘geek’, which is a term that some people dislike and don’t identify with. This is fair enough – how one identifies with and adopts labels for themselves is a personal thing, a point that Alice Roberts made earlier in the year.

Language evolves and so terms take on new meanings to reflect common usage. To my mind this means that the term ‘geek’ has taken on a new and (to my mind) positive meaning as “someone who is interested in a subject (usually intellectual or complex) for its own sake“, so I am happy with that description for myself – but I can understand that others feel differently.

In order to try to come up with a better hastag for a bony resource I made a poll that included a range of suggestions, the most popular of which can be seen below:

poll

Now obviously #bonegeeks comes out on top – presumably due to input from other people who self-identify as geeks, but there are enough people voting for alternatives to raise a warning flag that several people may feel actively excluded by use of term ‘geek’. In light of this I am unwilling to stick with #bonegeeks, but the general lack of consensus on alternative names leads me to reject the other options.

Where to go from here? The obvious answer is to go back to what we are trying to achieve and to think of a hashtag that is descriptive of the outcome rather than the contributors, so I suggest we use #bonepics so that both #bonegeeks and every other brand of osteology enthusiast who doesn’t consider themselves a geek can get on with making something rather awesome…