Friday mystery object #377 answer

Last week I gave you this unidentified skull from Dublin’s Dead Zoo to have a go at identifying:

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It didn’t prove too difficult to narrow it down, with everyone recognising it as a mustelid and Rémi immediately recognising it as being one of the Martens. But salliereynolds and Chris managed to get it down to the species, which is a bit of work.

There are around seven living species in the Genus Martes, although the total number varies depending on the sources you read. They have very similar skull shapes, the same dental formula and very similar tooth shape. In my experience the main feature to differentiate them lies in the auditory bullae.

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There are some decent online resources with images of Marten skulls, so it is possible to get a handle on some options. Each bulla is a 3 dimensional structure that is inflated in subtly different ways that are really hard to describe.

In a previous post I had a similar specimen (the same species as it happens) as a mystery object and I compared some bullae, but alas the image I referred to has since been removed. However, the important point is that there’s only one of the Martens that seems to have an outermost lobe that has a well-defined anterior sulcus (a fissure towards the front edge). This feature makes me think that this is a European Pine Marten Martes martes Linnaeus, 1758.

Thanks for your help in working it out!

Friday mystery object #373 answer

Last week I gave you this pretty cool skull to have a go at identifying:

 

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As everyone recognised, it’s the skull of a snake. I think that’s clear from those extremely long quadrate bones (highlighted in purple in the top view), with which the lower jaw articulates to allow a huge gape for swallowing prey whole. However, there are a lot of snakes out there – around 3,600 species, which means there are lots of possibilities for the species that this particular skull belongs to.

The side view allows us to rule out quite a few possibilities, since it’s clear from the teeth that this isn’t one of the front-fanged snakes (vipers and elapids).

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Rattlesnake skull, with its big front fangs.

The light construction of the skull suggests it’s not one of the constricting snakes, which have much more robust skulls for dealing with the forces generated by the struggles of relatively large prey.

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Python skull, with a robust construction for wrangling prey.

The teeth are quite small and although there are a couple of slightly longer ones in the tooth row, they hardly count as real fangs at a paltry 3mm long. So we’re probably dealing with one of the ‘non-venomous’ colubrid snakes (many of these are actually venomous, but lack the appropriate tools to deliver that venom through human skin).

Of course, there are still well over a thousand possible species in the Colubridae – but this is where you have to start ruling out possibilities by comparing the specimen against species that are common and widespread, to begin the process of narrowing down the options.

Since this specimen is in the Museum in Ireland, Europe is a good place to start looking for likely candidates (Ireland itself being famously devoid of native snakes). There is a rather old (published in 1913), but still very useful reference called The Snakes of Europe, by G. A. Boulenger which has a section on identifying species based on their skulls.

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Fig. 6Skull of Tropidonotus natrix. (From British Museum Catalogue of Snakes). Illustration from The Snakes of Europe, by G. A. Boulenger, 1913

If you take a look through, it quickly becomes apparent that there is one species that matches the mystery object very closely – even to the position of the slightly larger teeth. It’s a species that has an interesting defense mechanism that jennifermacaire referred to:

…The closest skull I could find is from a snake that likes to roll over and play dead…

This is a fascinating behaviour seen in several snake species, but Jennifer is correct that it is seen in the species that this skull is from – the European Grass snake Natrix sp.

Of course, the story then gets more complicated again, since a couple of subspecies of Grass snake have been elevated to species in the last few years. The Iberian subspecies Natrix natrix astreptophora was recognised as N. astreptophora in 2016 and the subspecies N. n. helvetica found west of the Rhine (including in the UK) was updated to N. helvetica in 2017.

These studies were based on genetics and I’ve yet to see any way of differentiating between these species using skeletal features, so for now the best I can say about this specimen is that it’s Natrix sp. I hope you enjoyed that little slither into the world of snakes, which seems to have opened a bit of a can of worms…

 

 

Friday mystery object #370 answer

Last week I gave you this really nice skull from the Dead Zoo to have a go at identifying:

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It proved a little more tricky than I thought it would, but I shouldn’t have been surprised given the poor quality of the photo and the fact that the cranium isn’t properly seated on the mandible (as pointed out by Allen Hazen).

Of course, that didn’t keep you all confused for too long. The large sinuses and relatively undifferentiated and widely-spaced teeth – except for those large canines – suggest that this is the skull of a some kind of seal.

Jeanie and salliereynolds noted the large, depressed opening over the nasal region, which is definitely one of the most distinctive features of this species. However, it also misled in the first place, with discussion of the possibility of it being from an Elephant Seal taking over for a while.

However, salliereynolds got back on the right track, while on Twitter Ray Chatterji was on the right track from the start with his suggestion:

The Hooded Seal Cystophora cristata (Erxleben, 1777) is really weird – well, the male is. He has an inflatable bladder on its head and one nostril contains a membrane that he can inflate to show off to other Hooded Seals.

I find it hard to think of this as anything other than nature’s attempt at making slightly disgusting balloon animals.

Well done to everyone who worked it out – I have a couple of fun guest mystery objects for you next week!

 

Friday mystery object #331

This week I have couple of specimens for you to have a go at identifying:

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I think these have been mislabelled and need their identifications checked to see if it’s a simple label swap or if it’s a deeper problem with the documentation. I won’t make it easier by providing the labels I’m suspect about – let’s see what you think working just from these images…

Have fun!

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 #234 answer

Last Friday I gave you this mystery skull to identify, which I discovered in a box of unidentified bits and bobs:

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It was pretty obvious that it was the skull of a big cat of some kind, with most of you suggesting a Jaguar or Cheetah (either of which would make me very happy as we have the skull of neither in the Horniman collection). Unfortunately it appears to belong to neither.

As I’ve mentioned  before, cats are quite difficult to differentiate from each other as they haven’t been diverging for all that long and their widespread distributions can mean that populations within a particular species can be quite variable in morphology. Leopards are a good example of this, with a (once continuous) range from Korea to South Africa.

Global distribution of the leopard (Panthera pardus) by Tommyknocker

Global distribution of the leopard (Panthera pardus) by Tommyknocker

As it turns out, this specimen is most likely from a Leopard Panthera pardus (Linnaeus, 1758), since it’s from an adult animal (as is clear from the well formed sagittal crest) but is on the small side for a Lion or Tiger and too big for a Cougar or Cheetah. It also lacks the broad post orbital region seen in the Cheetah and Snow Leopard, and it lacks the concave profile of both the Snow Leopard and Jaguar. All of these identification pointers can be found in this handy pdf by Margaret “Cookie” Sims.

Just to show you what I mean about the variability within a species, here’s a second skull from the same box, that also matches the Leopard identification.

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I expect the big difference in size is largely down to sexual dimorphism, but as you can see the overall proportions are quite different as well. This may be a difference between widely separated populations, or it could just be individual variation – either way it goes to show that cats are hard to identify.