Friday mystery object #233 answer

Last Friday I gave you a variety of mandibles to have a go at identifying. They lacked a scale bar and represented a range of different species that have similarities in mandible shape.

There were some great cryptic suggestions of identities, but it must be said that Jake came through with a really clear and pretty much spot-on list of suggestions. So here are the answers in a handy form that might be useful for reference:

mystery233b

The Sheep and Cow have a distinctive upward inflexion at the end of the mandible, with the Cow’s being so strong that the incisors start above the level of the top of the molar tooth row – unlike the Sheep’s.

This inflexion is much less marked in the Red Deer, which has a narrower body of the mandible, presumably relating to the less intensive chewing of a browser compared to grazers (grass is tough stuff). The Deer also has a notch along the bottom of the jaw, which Jake pointed out as a useful feature.

The Pig mandible tapers less overall, but is thicker at the end with the articulation – presumably because the omnivorous Pig is chewing differently, using the temporal muscles more than the masseter muscles and therefore needing a different area of the jaw for muscle attachment. The teeth are also pretty distinctive. Like the Pig, the Donkey mandible lacks the long and hooked coronoid process, but is also very triangular in shape with quite squared teeth – features typical of an equid.

So hopefully that gives you some pointers for telling some common herbivore mandibles apart when you don’t have a scale bar – a more common problem for some of us than you might think…

Friday mystery object #233

This Friday I have a challenge for you. Can you work out which five different species these mandibles come from?

mystery233

They are all different sizes and the lack of scale bars is deliberate – this is about trying to find useful features from the shape rather than the size, It’s not easy!

You can put your answers in the comments section below. Good luck!

Friday mystery object #232 answer

Last Friday I gave you this nice robust skull to identify:

mystery232

There was a healthy discussion about possible identifications, with the importance of scale mentioned more than once (by Jake, palaeosam, Lena and Robin Birrrdegg). Not only is this a robust skull, it’s also quite large, ruling out the British carnivores – and it clearly is a carnivore judging by the canines and the well-defined sagittal crest.

The lack of cutting and puncturing premolars and molars means that cats, dogs, hyaenas and other very carnivorous large carnivores can be ruled out, narrowing down the likely options in the right size range to the bears, as recognised by palaeosam, Ric Morris, Robin Birrrdegg, Will Viscardi, cromercrox, cackhandedkate, Lena, Daniel Calleri, henstridgesj and Carlos.

The species is a bit more difficult to work out, but the big sagittal crest and fused sutures suggests that this is not an juvenile bear, meaning it’s too small for a bear of the Brown  or Polar variety. That still leaves quite a range of other possible bears, but the pronounced forehead and long square muzzle rules out the Giant Panda, Sun Bear, Spectacled Bear and Asiatic Black Bear, while the big robust incisors rule out the Sloth Bear. That leaves the American Black Bear Ursus americanus Pallas, 1780.

Ursus americanus by Mike Bender/U.S. Fish and Wildlife Service, 2008

Ursus americanus by Mike Bender/U.S. Fish and Wildlife Service, 2008

So well done to cromercrox, Carlos and Robin Birdeggg who all got the species correct!

Friday mystery object #231 answer

Last Friday I gave you this distinctive skull to identify:

mystery231

I knew it would be a bit of an easy one, given the highly unusual teeth, but it seemed too interesting a specimen to not use.

As cryptically suggested by many of you (Jamie Revell, Nigel Monaghan, henstridgesj, rachel, cromercrox, Robin Birrrdegg, Allen Hazen and Crispin), this is indeed the skull of a Crabeater Seal Lobodon carcinophaga (Hombron & Jacquinot, 1842).

Jerzy Strzelecki, 2000

These seals are specialised for catching krill, hence the strange shape and tightly fitting nature of their teeth, which act as a filter to strain the tiny crustaceans from ocean water.

Because these seals live in the waters all around the Antarctic, monitoring their population is particularly difficult, so estimates of their numbers vary considerably, from 2 million to 12 million (which is the more likely figure).

As with most abundant animals they have predators, in particular Leopard Seals. Apparently 78% of adult Crabeaters bear scars of Leopard Seal attacks, which can be seen clearly on the live individual in the image above. Most of the attacks happen before the Crabeaters reach a year old and get a bit too big to be easy prey, but in that first year there is apparently a huge mortality rate, with only 20% of seals making it to their first birthday. Good old Mother Nature is never one for sentiment.

Friday mystery object #231

This week I have a very distinctive skull for you to identify:

mystery231

Because I expect some of you to work out what it is straight away, can you make your answer cryptic please, to give other people an opportunity to work it out.

I look forward seeing some cunning and clever hints at what this is!

 

Friday mystery object #229 answer

Last Friday I was at the SPHNHC, NatSCA and GCG joint conference in Cardiff, which provided a fantastic opportunity to catch up with natural science curators, conservators and collections managers from all over the world, but which gave me limited time to spend on the mystery object.

As a result you ended up with an object that made an appearance in a ‘feely box’ at a fun pub quiz organised by guys at the Oxford Museum of Natural History.

Feely boxes in action

Feely boxes in action

Lurking within...

Lurking within…

It’s not the prettiest object but it’s characteristic shape and structure makes it readily identifiable using touch.

Jake spotted that it was a horizontal section through a skull, including the palate and Maxine and Julie Howard recognised the tusk alveoli extending from the maxilla, and correctly suggested Pumbaa, or Warthog Phacochoerus africanus (Gmelin, 1788).

Touch is an often under-appreciated sense in science, but it can be used to identify some specimens and provide a new perspective on the evolution of forms in nature. This is something I came to realise when working at the National Museum of Ireland – Natural History in Dublin, where I was fortunate enough to meet evolutionary biologist Dr Geerat Vermeij, who has been blind since birth, yet is able to identify shells to species and read part of their life history from touch alone.

Geerat Vermeij, Evolutionary Biologist, Reading A Shell’s Story from Shape of Life on Vimeo.

 

Bonus mystery object

I usually offer up a mystery object on Friday, but here’ a bonus object that landed on my desk this morning.

image

Apparently it was found in a horsefield in Kent, I have narrowed down the likely species of the animal that ‘donated’ the bone to a couple of options, but thought you might like to have a go as well, before the specimen is handed over to our Anthropologists to inspect the engraved designs.

As usual can can leave your comments below. Have fun!

Friday mystery object #228 answer

Last Friday I gave you these bits of mystery forelimb (scapula and humerus) to identify:

mystery228

I thought it would be an easy one, since it’s from a very common species with a near global distribution – plus the humerus has quite a characteristic crest along the proximal end, from the shoulder articulation to the middle of the bone.

Most people who commented noticed this crest and Jake suggested that it had adaptive features (along with the scapula), maybe for a specialised way of life.

As it turns out, these bones come from an animal that is probably best described as a specialist generalist – a Brown Rat Rattus norvegicus (Berkenhout, 1769).

Rattus norvegicus, the Brown Rat. Image by National Park Service

These versatile and intelligent animals are very good climbers and brilliant swimmers, using their forelimbs to both get around and manipulate food.

This particular rat was a male pet rat purchased from Harrods in October 1960 – I get the impression it didn’t survive for that long, since the humerus head hasn’t fully fused. You can’t buy pets from Harrods any more, so this specimen not only shows us what a rat’s humerus and scapula look like, but it also represents a teeny-tiny piece of British history.

Friday mystery object #228

This week’s mystery object is a bit of a break from the cat skulls. Any idea what these two bones are and what species they’re from?

mystery228

As always, you can put your thoughts and suggestions in the comments section below, but if you think it’s easy please try to be a bit cryptic in your response, to give other people a chance. Enjoy!

Friday mystery object #227

This week I thought I should mop up the last of the smaller cats as a spot-the-difference:

mystery227

What do you think are the diagnostic features that separate these two skulls (bonus points for species identifications)?

I’m really keen to get your thoughts on this, so please put your observations in the comments section below. Thanks!

Friday mystery object #225 answer

Last Friday I gave you this felid skull to identify:

mystery225

As with the other cats over the last few weeks, it’s been difficult to find really clear diagnostic features.

The size helps narrow down the possibilities and the lack of divided auditory bullae rules out some of the species of Lynx, as does the presence of the small first premolar.

However, beyond that there isn’t much to really differentiate this cat from other species, apart from general features of relative proportion (height vs width vs length) and perhaps the angle of the rear part of the sagittal crest (which will probably vary between individuals).

Nonetheless, henstridgesj managed to correctly identify this as an Ocelot Leopardus pardalis (Linnaeus, 1758), one of the largest of the small cats in South America.

Ocelot, 2003 from US Fish & Wildlife Service, Image Archive

My challenge is going to be find a way to pull together the variety of cat skulls we’ve had for the last few weeks, to help make cat skulls a little easier to identify in the future – if that’s even possible. No pressure…

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 #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 frankliniiSpermophilus 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 #216 answer

Last Friday I gave you this mystery sternum to identify:

mystery216

I had a rough idea of the family, but I was less certain about the species. As it turns out I’m now less sure of the family than I was before, in light of some useful comments.

At first I thought this was the sternum of a member of the Strigidae or the ‘True Owls’ – something that Jake also thought with his suggestion of Tawny Owl Strix aluco, but henstridgesj and Daniel Jones raised the possibility of it being from a seabird and Daniel Calleri suggested it could also be from a member of the Halcyonidae or the ‘Tree Kingfisher’ family.

With the Christmas and New Year break I haven’t had a chance to get to our stores to check specimens, but there is a very useful website that deals with seabird osteology (helpfully called Seabird Osteology) which has some images of sterna. Several of the Procellariiformes (the order containing the Albatrosses, Petrels, Shearwaters, etc.) have a similarly short sternum with a double notched bottom margin, as do some of the Laridae or the Gull family.

I also checked an image of a Kookaburra from a previous mystery object, which doesn’t show the sternum well, but which does hint at a double notched bottom margin:

Laughing Kookaburra Dacelo novaeguineae skeleton

Laughing Kookaburra (Dacelo novaeguineae) skeleton

This has left me slightly less confident that last week’s mystery object is from an owl, but here are a couple of other owl sterna for comparison:

Barn Owl Tyto alba sternum and coracoid

Barn Owl (Tyto alba) sternum and coracoid

As you can see, the Barn Owl sternum above doesn’t quite have the double notch, although the size is about right. The Eurasian Eagle Owl sternum below (ignore the coracoids and other bits of the pectoral girdle) is a much closer fit, although substantially larger.

Bubo_bubo_sternum_coracoid

Eurasian Eagle Owl (Bubo bubo) sternum, coracoid, furcula and scapula

I’ll see if I can find a Tawny Owl sternum to check against, because the shape does seem pretty good for one of the Strigidae and the size is about the same as a Barn Owl, which is in a different family, but has a size range that overlaps with the Tawny Owl. Of course, it could also be from one of the other medium sized owls, like the Long-eared or Short-eared Owls… more to come!

UPDATE 14:30 on 3rd January 2014

Here’s a Tawny Owl sternum!

Tawny Owl (Strix aluco) sternum

It’s pretty close, but the notches seem a bit deeper, so perhaps one of the Asioninae (Eared Owls) might be a better match for the mystery object?