Friday mystery object #285 answer

Last week I gave you this unassuming bit of bone, that I found with no identification in the Grant Museum of Zoology stores:

mystery285

Daniel Jones and Daniel Calleri identified the element as a radius, but beyond that there was a general feeling that identification of species was a bit on the tricky side. Palfreyman1414 pointed out that it’s something approximately human sized, with Lena ruling out an ungulate, suggesting that it could be from a carnivore or possibly a marsupial.

I must admit that my mind immediately went to carnivores and I initially thought it could be from a Black Bear, since it’s fairly robust and about the right length. However, after checking the ever helpful Adams & Crabtree book I realised that bears are even more chunky than this.

It didn’t look right for a dog since they are straighter, have a flatter profile and a narrower distal end. However, it did look right for a big cat and I’m fairly certain that it’s from a Leopard Panther pardus (Linnaeus, 1758). If you want to compare a Leopard with a Dog radius you can see them compared in this paper, along with a good description of the bones of the Leopard forearm.

A bit of a tricky challenge – so next time I may try to do something a bit more distinctive!

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 #283 answer

Last week I gave you this zoomed in picture of a specimen to have a go at identifying:

mystery283

It was a bit tricky, so I also gave you this bonus clue to help:

mystery283_bonus

I was impressed to see that, despite the limited information available from the images provided, many of you managed to work out that this shows the lightweight ‘honeycomb’ structure that supports the casque of a hornbill.

That was the first challenge but, as ever, I was keen to see if you could get the identification to species – far more of a challenge considering the lack of a side view of the skull and lack of a scale. To make up for that I’ve decided to provide the necessary image here:

Ceratogymna atrata skull

I won’t say what species this is in this post, as I normally would, just to give some more of you a chance to make the identification yourself. However, what I will say is that the very first response by Wood contained a link to an image of the correct species and later to a blogpost featuring this very specimen. In that post there is a discussion about the appearance of the casque, with speculation about whether it had been damaged during preparation, resulting in its appearance. However, as Richard Lawrence pointed out, this appearance is actually normal for the skulls of several species of hornbill.

I will also say that the discussion between Daniel Calleri & Dan Jones and Richard Lawrence about whether it was a hornbill from a genus starting with A or B was interesting and I initially thought it was an A, but am now convinced that it’s a C.

If you’re desperate to know which species it’s from, here’s a link to the skullsite.com page about it.

 

Friday mystery object #283

This week I have a mystery object for you that’s a bit different from the usual. Any idea what this zoomed in picture is showing?

mystery283

It’s probably a bit of a tricky one, so if you want an extra image that makes it much easier you can click on this link for a bonus clue.

Please leave your suggestions in the comments below – I’d love to find out your thoughts and let me know if you needed the clue. Have fun!

Friday mystery object #282 answer

Last week I gave you this mystery object supplied by Dr David Hone:mystery282

This is the premaxilla of a fish, but that doesn’t narrow things down much, since there are 28,000 species of bony fish, leaving a huge range of possibilities.

There were several suggestions of Wolf Fish, which is what I originally thought it was myself, but that’s not what it is. Then the suggestions of various Wrasse species started cropping up – which is a lot more likely.

My first look at Wrasse teeth came when I tried to identify the fish used in the Horniman’s Merman:

SONY DSC

There are a lot of Wrasse, over 600 species in fact, so it can be hard to narrow down the species, especially when few comparative specimens are available.

One very helpful osteology resource for identifying fish from their bony bits is Osteobase which lets you pick a bone and start making comparisons. It’s worth keeping in mind that you need to really explore the taxonomic tree on the left of the page to get a real appreciation of how useful it is – so for example, after selecting the premaxilla, if you look at the Perciformes (the Order containing the Wrasse) you see a huge range of premaxilla specimens that help narrow down the bone you’re trying to identify.

This clearly shows that the Labridae is definitely the right family for the mystery object and the Mexican Hogfish Bodianus diplotaenia (Gill, 1862) is a very close match.

So congratulations to Richard Lawrence who I think has it right, especially since the specimen was found within the range of this species. I hope you all enjoyed the challenge!