Friday mystery object #374 answer

Last week I gave you this ‘unidentified bone’ to have a go at identifying:

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I say bone, but as was pointed out on Twitter, perhaps the label reads something else…

‘Boner’ would of course be an accurate slip, because this is clearly a baculum (aka the penile bone, os penis, os priapi, or oosik in the case of pinnipeds). I don’t think the slip was deliberate though, since I removed a piece of information from the label for the sake of the challenge:

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I can only imagine that this baculum was found with some seal bones and was not recognised as being part of the skeleton and therefore removed. There’s no reference to where the rest of the seal bones are, which is bit of a problem if they are in the collection.

I’ve blogged about penile bones on several occasions, since as far back as in 2010.  Bacula are often quite distinctive, allowing species identifications based on their morphology. But this particular specimen has proven hard to find good specific comparative material or images (online or in publications) to do comparisons against.

However, from looking at the few seal bacula that do have illustrations in publications, and scouring the internet for articulated seal skeletons with bacula in place, I think it’s probably from male Grey Seal Halichoerus grypus (Fabricius, 1791). If so, this individual would have likely been aged 10 years or over.

This age suggestion is based on the length and robustness of the specimen, which in Grey Seals has been shown to correlate quite closely with age and maturity in the males (Hewer, 1964; Van Bree, 1972). This interesting bit of information aside, I unfortunately couldn’t find the clues that led palfreyman1414 to the Holmesian deduction:

…So, apart from the fact that they are right-handed, have been to Afghanistan, currently work as a haberdasher’s spool threader and have fallen on hard times, I got nothing.

But bacula are informative bones, so I’m sure there is a lot of additional information available from the specimen that I’ve not deduced.

All of you worked out what this bone(r) was, and several people recognised it as being from a seal of some kind, both in the blog comments and on Twitter. There was also a suggestion of Grey Seal from Conor Ryan:

I hope you had fun with this mystery boner! Oh wait, that sounds really wrong.

 

Friday mystery object #374

Recently I was looking at some skeletal specimens in the Dead Zoo stores, to help with a research enquiry. I came across a drawer of unidentified bones and as you might have guessed, I was delighted. Over the next few weeks I’ll be sharing some of these to get your thoughts on identifications.

To get started, here’s a good one:

Any ideas what bone this is and what animal it’s from? You can leave your ideas in the comments section below.

Have fun!

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 #372 answer

First of all, I’d like to wish you a very happy and healthy 2020!

Last year I gave you this festive-looking beetle to try your hand at identifying:

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It was a bit of a tricky one to get to species, since beetles are notorious for their huge diversity, plus they can vary in appearance quite significantly within a species.

James Bryant recognised this as a member of the Buprestidae, which is a family of wood-boring beetles that are commonly known as Jewel Beetles due to their metallic and iridescent colours. In fact, the wing cases (or elytra)  of some of the most colourful of these beetles have been used in traditional beetlewing jewellery in the parts of Asia where they are found.

Going beyond the family, the identification katedmonson provided through a great cryptic clue was spot-on (assuming I understood it properly). This particular specimen is an example of Chrysochroa rajah Gory, 1840, but in the collection it is still labelled under the synonym C. chinensis.

This species is one of those with a wide distribution, several subspecies and a variety of different colours and patterns, which can make it hard to identify based on just an image of the overall body (or habitus as it’s referred to by entomologists). Just to give you an idea of what I mean, here’s an example of the same species in the National Museum, Prague:

Chrysochroa rajah from southern China. Photo by Hectonichus 2010

Blue and green form of Chrysochroa rajah from southern China. Photo by Hectonichus 2010

So well done to katedmonson for getting this tricky identification. Look out for another mystery next week!

Friday mystery object #371 answer(ish)

Last week I gave you these two genuine mystery specimens from Katharine Edmonson to get your thoughts on:

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It was most definitely NOT an easy challenge, and I’m still not sure I know the answer to either, even after looking at every species I can think of that might have similar structures.

These are both clearly teeth, considering the internal details:

One image shows the root area of a full tooth, and one shows a section through a tooth – both of which provide really useful information. For example, the full tooth has a central dentine growth that you often find in animals that deal with a lot of strain on the tooth or where infection has got in (I’ve shown this before in elephant ivory).

The sectioned tooth shows a zone of dentine in the middle that suggests some hard use. Notably, that zone matches the shape of the cross section, so those grooves in the sides of the tooth aren’t from wear – they must be intrinsic to the tooth shape.

Generally, tusk cross sectional shape reflects the shape of the socket (until it gets worn down) – so that gives a pretty good way of narrowing down possible options. For example, I’d discount walrus, since they have an almost rectangular section. Warthog tusks have a section somewhere between the number 8 and a mushroom in shape, and Hippopotamuses have a triangular section to their canines, but their incisors are quite circular in section.

Warthog tusk socket

Warthog tusk socket

Then there are wear facets, that can give teeth and tusks a characteristic shape. Hippo canines grow in a corkscrew if unworn, but by rubbing against each other they remain sharp and fresh (like rodent teeth).

This means that teeth and tusks can look weird if the normal wear is disrupted, either by not happening or by happening too much.

There are also unexpected tusks that need to be considered, like the Indian Rhinoceros or dugongs that have hidden tusks.

Of course, some animals have really weird tusks, especially when they’re young or if they’ve experience something that leaves the tusks deformed or altered – which can make identification really hard.

There were a lot of suggestions of Sperm Whale tooth, which is a possibility, but I’ve not seen any that really come close. It may be that both of these are tusks from something more unusual, like beaked whales, but I have looked at a lot of examples of beaked whale teeth and I can’t find any examples that match either of these.

On balance, I think that the first of the tusks may be a Hippopotamus incisor that’s been misaligned with another tooth, causing excessive wear and horizontal stress lines to appear during tooth growth – this is rampant speculation I hasten to add. The second looks a lot more like a Warthog tusk in section than anything else, although the end is more spade-like than I’d expect.

So, after a lot of consideration I’m still uncertain of the identification of either of these, and I would be delighted to hear if you have any more thoughts!