Friday mystery object #352 answer

Last week I gave you this bird to have a go at identifying:

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I thought that some of you would find it quite easy and I wasn’t wrong, although it’s not quite as straightforward as I thought.

Our regular ornithology expert Wouter van Gestel was straight in with an interesting answer that highlights some of the idiosyncrasies of museum specimens, where the colour of features like bills and legs can fade after death. This can make identifications tricky, since colour can play an important role in distinguishing between species in the same genus. In addition, the maturity of the animal can also complicate identifications, since juveniles can have different colours and markings to adults.

That makes this specimen doubly hard to identify and jennifermacaire pointed out an additional idiosyncrasy – the glass eye used by the taxidermist. The choice of eye is an important one, since eyes play an important role in making something look as it did when it was alive. In this case I think they used an eye that was too large with too much iris showing.

Both Wouter and Jennifer identified this as a Tropicbird, and both thought it was the White-tailed species. However, according to the Museum database the specimen is a young Red-billed Tropicbird Phaeton aethereus Linnaeus, 1758.

Red-billed tropicbird (Phaethon aethereus mesonauta) with chick, Little Tobago by Charles J Sharp, 2014

Red-billed tropicbird with chick – note the yellow bill on the chick. Image by Charles J Sharp, 2014

Now I’m going to check the identification again, since it isn’t unusual for specimens to be misidentified. This is a problem in museums, since specimens come from all sorts of sources and not all of them are necessarily expert.

I recently had to check the identification of a couple of Tern specimens from Jamaica for an enquiry. If the specimens had been the species they were originally recorded as, it would have been the only record of the species on Jamaica and it may have hinted at a lost population. In the end it was a simple misidentification of a common species.

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This is part of the reason why specimens in museums are so important – they provide a primary record that can be checked to ensure information about biodiversity is correct, so we can understand things like changes in population distribution with confidence.

Friday mystery object #327 answer

Last week I gave you this mystery bone to identify:

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As I suspected, it was simultaneously easy and difficult: easy because it’s clearly an os penis or baculum; difficult because it can be hard to narrow down the species to which a baculum belongs without having specimens for comparison. For some reason people can be funny about penis bones and, despite the fact that male animals tend to be over-represented in museums, the baculum will often have been removed or not included in skeletal mounts.

That said, Steph came closest, getting the right family with the clue:

Bac to the bear-minimum I would guess?

If you remember one of my past posts I showed an image of the baculum mounted on the skeleton of a Giant Panda in Berlin (more about this below):

Panda_penis_bone

You can see that, although it differs slightly with a bit of a dip towards the tip, it’s rather similar in structure to the mystery object.

Oddly however, it appears that this baculum on the Berlin Panda specimen has been switched for that of a different bear species. Pandas have a very distinctive reduced baculum with wings (see below), that looks nothing like this, which is more similar to the os penis of a Spectacled Bear (or possibly a Polar Bear at a push).

The mystery object is actually the baculum of a Sloth Bear Melursus ursinus (Shaw, 1791).

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N.B. note that the writer of this label couldn’t quite bring themselves to write the full word “penis”

In future, should you ever find yourself with an unidentified bear penis on your hands, I suggest taking a look at this handy figure by Abella et al. 2013¹:

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Baculum in laterial view of: A Helarctos malayanus; B Ursus thibetanus; C Tremarctos ornatus; D Ursus americanus; E Melursus ursinus; F Ursus arctos; G Ursus maritimus; H Indarctos arctoides; I Ventral view of the Baculum of Ailuropoda melanoleuca; J Dorsal view of the baculum of Ailuropoda melanoleuca.

So in answering one mystery object we’ve uncovered a far bigger mystery – how did the Berlin Panda end up with the wrong penis?

 

¹Abella J, Valenciano A, Pérez-Ramos A, Montoya P, Morales J (2013) On the Socio-Sexual Behaviour of the Extinct Ursid Indarctos arctoides: An Approach Based on Its Baculum Size and Morphology. PLoS ONE 8(9): e73711. https://doi.org/10.1371/journal.pone.0073711

Friday mystery object #284 answer

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

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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:

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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.

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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:

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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:

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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”.

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Labelled “Sheep” but actually a Gerenuk.

This is what a sheep looks like:

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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):

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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:

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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!