Friday mystery object #284 answer

Last week I gave you this part of a skull to have a go at identifying:

mystery284

It’s quite a distinctive structure and very particular to one particular group of mammals. It is of course an external auditory meatus (or ear hole as it’s more commonly known), but instead of opening directly into the auditory bulla (the inflated bony bulb that holds the ear bones) it has a long and robust tube.

Lee Post, Daniel Calleri & Dan Jones and Allen Hazen recognised this characteristic feature as belonging to a Beaver and Richard Lawrence went one better and narrowed it down to Castor canadensis Kuhl, 1820 – an identification that I agree with having seen the whole skull:

beaver_skull

I’m not sure if there’s any real functional reason for the ear tube, but it looks to me like it might be a “spandrel” a feature that’s an artefact of another adaptive feature – in this case the articulation of the mandible.

beaver_jaw

Gnawing through a tree trunk is no easy task, so it’s not surprising that the Beaver has some serious adaptations to deal with the work involved. Unlike carnivores, which have a fixed lateral mandibular articulation powered mainly by the temporalis muscles, rodents have a dorso-ventral articulation usually powered by the masseter muscles, which allows the jaw to move backward and forward. In the Beaver the sagittal crest suggests that the temporal muscles are more involved than usual which, with the orientation of the articulation, may necessitate the ear tubes as lateral braces against which the mandible can secondarily articulate. That’s my guess…

Great work on identifying this specimen using very limited information!

Friday mystery object #280

Last week the answer to the mystery object was a Gharial – a very weird crocodilian from India. I realised that I didn’t know much about identifying the Crocodyliformes, so I thought it might be fun to have a go at working out what this species might be:

mystery280

As always, I would love to hear your thoughts below and let’s see if we can find some good diagnostic features!

Friday mystery object #273 answer

Last week I gave you this mystery object to get your input on:

mystery273

It was labelled Ovis aries, which didn’t ring quite true for me, so I thought it would be good to see if you also had other ideas, since I’ve noticed that there is a tendency for ungulates of a certain size in museum collections to be assumed to be Sheep.

In other museums I’ve found female Red Deer, Gerenuk and on one occasion even a Badger skull that had been labelled “Sheep”.

mystery273-gerenuk

Labelled “Sheep” but actually a Gerenuk.

This is what a sheep looks like:

mystery273-sheep

You’ll probably notice the “Roman nose” that is quite distinctively sheepy, it also has no gaps between the premaxilla and maxilla and there is a small depression in front of the eye.

When you look underneath, one of the key things that jumps out is the difference in size of the auditory bullae (mystery on the left, sheep on the right):

mystery273-mystery_and_shee

So I’m pretty sure that the mystery object isn’t a sheep, but what is it?

There were lots of suggestions of exotic and interesting ungulates, but after looking at the skulls of a huge number of ungulates I can to the conclusion that Latinka Hristova and Jake were on the right track with the simple suggestion of Goat Capra hircus (Linnaeus, 1758).

Taking a look at Goat specimens on the incredibly useful Mammalian Crania Photographic Archive has convinced me that this is what the mystery object actually is. Not a million miles from Sheep I suppose, but they are different and it’s helpful finding some small differences that help distinguish between them.

Thanks for your input!

Friday mystery object #272

This week I have another specimen from the Grant Museum of Zoology for you to try your hand at identifying:

mystery272

I have a feeling that it may be easy to get this identification to Family level, but species may prove a little bit more tricky.

I’d love to hear what you think it might be, so leave your suggestions in the comments box below. Have fun!

Friday mystery object #271 answer

Last Friday I gave you this odd looking V-shaped bone to identify:

mystery271a

It led to a lot of speculation on Facebook and Twitter, with ideas including a bird wishbone, hyoid or mandible. However, the comments on the blog tended to be a little more focussed in the area of the mandible of an ant-eating mammal.

The two little prongs at the anterior of this lower jaw are a bit of a give-away about which type of ant-eating mammal it is, as they are only seen on one family. When you look at the additional image I provided it becomes even easier to work out which:

mystery271b

As most of you correctly worked out, this is a specimen of Pangolin, of which there are four species in the genus Manis (thanks Allen Hazen for the correction – there are more like eight species in the family). I found this nice illustration of the skulls of the various species, to help narrow it down even further:

Anatomical and zoological researches: comprising an account of the zoological results of the two expeditions to western Yunnan in 1868 and 1875; and a monograph of the two cetacean genera, Platanista and Orcella. John Anderson, 1878.

Anatomical and zoological researches: comprising an account of the zoological results of the two expeditions to western Yunnan in 1868 and 1875; and a monograph of the two cetacean genera, Platanista and Orcella. John Anderson, 1878.

So it appears from the morphology of the premaxilla, zygomatic region and nasals that this is a Sunda Pangolin, Manis javanica Desmarest, 1822.

Manis javanica by Piekfrosch, 2006

Manis javanica by Piekfrosch, 2006

These unusual scaly insectivores are critically endangered due to poaching for their meat, skin and scales for the Chinese market, with their population suspected to have declined by 80% in the last 20 years, despite having a protected status. Sad to say that their ability to roll into an armoured ball does nothing to protect them from people.

Friday mystery object #271

This week I have a mystery object for you from the Grant Museum of Zoology that’s either a bit too easy, or a bit mean:

mystery271a

If you’re not a fully paid-up bonegeek, you might like to have a bit of an additional clue; if so, click here.

Please keep your answers in the comments section cryptic, so everyone gets a chance to have a go at working it out without spoilers. Have fun!