Friday mystery object #461

I have a great guest mystery object for you this week. It comes from the wonderful Catherine McCarney, who is manager of the Dissection Room at the UCD School of Veterinary Medicine:

Here’s what Catherine has to say about it:

This object is a bone fragment from an unknown animal. It was discovered while cataloging an old box of historic specimens in the UCD School of Veterinary Medicine. It’s of limited use in the vet program, but my Zoologist background is keen on answering the mystery rather than simply discarding it. It has me stumped, it’s light weight (just 26g) had me thinking it must be from a bird, but some features are reptile like.

So, do you have any thoughts on what this mystery object might be?

As ever, you can leave your thoughts, questions and suggestions in the comments box below. Happy sleuthing!

Friday mystery object #460 answer

Last week I gave you a somewhat challenging bony mystery object to have a go at identifying:

The first challenge is recognising the type of bone. It’s not part of the axial skeleton (like the skull, vertebrae, ribs, etc) and it’s not one of the long bones, which are very distinctive.bits of the appendicular skeleton (which includes the pelvis, shoulders and limbs).

So that leaves the distal bits of the limbs, which tend to be relatively small. This is where it helps to be familiar with bone shapes – and this sort of elongated rectangle with an articulation at just one end is fairly distinctively a heel bone or calcaneus. (N.B. the end without the articulation provides a connection point for the Achilles’ tendon.)

At 8cm it’s fairly large, so that suggests it’s from a fairly large animal. This actually confused me more than it probably should have – but more about that in a minute.

The calcaneus is a very functionally important piece of bone, so the shape will reflect the use. However, the use of a leg tends to be broadly similar between closely related animals. Therefore, while it’s fairly straightforward to rule out things like carnivores and primates by using online reference resources like the incredible helpful BoneID site, it all gets more complicated when you realise this is from a member of the Artiodactyla, which has 270 or so species.

Common species are a good place to start with comparisons, since you are more likely to find their bones. So I started by looking at Deer, Horse, Pig, Sheep and Goat. I probably got a bit sidetracked by the size of this particular specimen at first, but as I have maintained on many occasions, size can be misleading and shape is always a better factor upon which to base an identification, since animals of the same species can come in different sizes.

After ruling out Deer, Horse and Pig I found myself wavering between Sheep and Goat. To dig into the shape differences a bit more, I took a look at an interesting paper on geometric morphometric comparison between the calcanea of Sheep and Goats by Lloveras, et al. 2022. The shape is very similar between the two species, but the differences identified in that paper have me leaniing towards the idea that this mystery object is most likely the calcaneus of a Sheep Ovis aries Linnaeus, 1758.

The differences are quite hard to decribe in a non-technical way, in the paper it goes like this:

According to our results the shape differences across sheep and goat calcanea are mostly located on the calcaneal tuber and neck, the sustentacular tali region, the malleolus articular surface and the cubonavicular articular surface. In general terms, in sheep, the calcaneal tuber tends to be more concave on the anterior side and the calcaneum neck, the sustentacular tali region and the cubonavicular articular surface tend to be wider. In opposition, in goats, the malleolus articular surface region tends to be shorter and more prominent anteriorly. These morphological differences could reflect the functional adaptation of these animals in different habitats that demand different methods of locomotion. While the sheep is adapted to running across flat land, the goat is adapted to rocky escarpments.

Lloveras, et al. 2022

In general terms it’s probably sufficient to take a look at the specimens on BoneID (you’ll need to flip the mystery object in your head, as it’s upside down and a mirror image since it’s from the right leg rather than the left, which is what’s shown on the BoneID site). The angles and extent of the articulations seem to be better defined in Sheep and match more closely to the mystery object.

So congratulations to Adam, who was the first to figure it out (beating me to it, which led to some rapid back-pedalling by me in the comments!)

Finally, back to the size. All I can say is that the sheep that this calcaneus came from was, well, quite possibly memeworthy…

Friday mystery object #459 answer

Last week I gave you this guest mystery object from Andy Taylor:

Image by Andy Taylor, 2023

Those paired incisors and the large diastema (or gap) behind them are characteristic of a rodent, so that narrows down the possible options by not very much, since there are well over 2250 species.

However, this specimen also has a very large infraorbital canal (that big forward-facing hole in front of the eye socket), which is a feature of the hystricomorphs – the group containing capybaras, porcupines, chinchillas, guinea pigs, hutias and suchlike. The teeth are an additional give-away for the group, with their discrete little patterns on the grinding surfaces:

Image by Andy Taylor, 2023
Image by Andy Taylor, 2023

The scale of this specimen threw me a little at first, as I’m used to dealing with metric, but this scalebar has 16 subdivisions, so it muct be imperial. Which really helps, as it means this skull is quite large for a rodent – somewhere in the region of 5 inches or 12.7cm. That immediately narrows things down a lot more.

An additional clue is in the narrow skull profile:

Image by Andy Taylor, 2023

A lot of rodents have a lower and broader skull and this kind of shape is what I expect to see from a species that moves through dense undergrowth rather than climbing, digging or swimming. This, combined with all the other clues, led me to the agoutis.

There are 12 species of agouti, so we’re still not quite there with the identification. Most species that I can find comparative material for have a significantly longer rostrum than this specimen (relative to the rest of the skull), but there are some species I’ve not been able to find a really reliable reference skull to compare against.

There is one species where I couldn’t find a great skull comparison, but which appears in living individuals to have a relatively short snout and the skull image I could find also appears to be less nasally advantaged than most agoutis. That was the Brazilian or Red-rumped Agiouti Dasyprocta leporina (Linnaeus, 1758).

I’d be keen to take a further look with some good quality reference material, but I’m reasonably happy with this. The advantage of good comparative material is that it really helps make those detailed observations about particular shapes and sizes that can be hard to properly recognise from a photo.

In a strange, but very welcome cooincidence, I had the good fortune to meet up with Andy last Friday evening. I was at the NatSCA conference in the UK – which was held just a short journey from where Andy lives. It offered a great chance to chat with a fellow bone geek and natural history fanatic and I hope to have some more guest objects from Andy and his amazing collection in the future!

Friday mystery object #459

This week I am have a great guest mystery object from Andy Taylor for you to have a go at identifying:

Image by Andy Taylor, 2023
Image by Andy Taylor, 2023
Image by Andy Taylor, 2023
Image by Andy Taylor, 2023

Here’s what Andy says about the specimen:

On Sunday, myself and Sophie Bagshaw were working through specimens that were donated to me from a person who had been given them by a zoological park. The specimen in question was part of a huge shipment of almost 140 frozen specimens that were in various states of preparation and were mostly head specimens. … I have a large rodent skull that I’m struggling to ID

Andy and Sophie have been doing great stuff with osteology for educational purposes for a while now, so it was a real pleasure to get a question like this, and it seems like a perfect opportunity for the community here to add their thoughts.

So, what do you think it is? Let us know below!

Friday mystery object #458 answer

Last week I gave you this skull from the collections of the Dead Zoo, which had been misidentified and that came to light when Dr George Argyros was doing some research on the carnivore skeletons:

The label attached to this specimen indicated that this is the skull of a Leopard, which is clearly wrong. The label also identified the specimen as having been collected in East Africa by Major A.W.V. Plunkett.

Labels like this worry me. Not because they contain a misidentification, but because they may indicate that someone in the past has mixed up the specimen labels. This is a much bigger problem than a simple misidentification, as it can mean the real specimen has become dissociated from its information.

The huge, robust teeth of this specimen should make it fairly clear that it belongs to one of those specialist bone-crushers – the hyenas:

However, there are three species of hyena to choose from (I’m leaving the Aardwolf of this, since they don’t match this dental morphology even remotely).

My first thought was that this specimen is on the small side for a Spotted Hyena:

Striped Hyena on left, Spotted Hyena on right

Size is seldom a definitive feature, especially in species that display sexual dimorphism, but what is more useful is the detail of the tiny molar at the back of the maxillary toothrow. This is absent in Spotted Hyenas, but it occurs in both Striped and Brown Hyenas.

So you might ask, how do we distinguish between Striped and Brown Hyenas? This is a good question. For starters, it’s hard to find enough reliable good images of the Brown Hyena’s skull online that show the details needed to distinguish between the species.

However, a bit of searching highlighted that the Brown Hyena has a shorter and more robust angular process of the mandible than the Striped – and the mystery object.

Image of Brown Hyena skull by David J. Stang, 2005.

This long angular process was spotted by katedmonson, but Adam Yates was the first with the identification of Striped Hyena Hyaena hyaena (Linnaeus, 1758).

This one proved a little trickier than I thought at first, due to the similarities between the Brown and the Striped species. But I’m a little relieved that the consensus fell on Striped, both here on the blog, and between myself and George, since the Striped Hyena is found in East Africa, whereas the Brown is limited to South Africa.

This at least agrees with the locality on the label, so it may well have simply been misidentified when the specimen was acquired – especially since it looks like it was skeletonised naturally, so it may have been found dead and already defleshed, making it harder to identify.

I hope you enjoyed the challenge!

Friday mystery object #458

Since everyone seemed to have fun with last week’s mystery skull, I have another that was misidentified in the Dead Zoo’s collections and which came to light during Dr George Argyros’ recent research visit:

Do you recognise this species from its skull?

As usual, you can ask questions or leave suggestion in the comments box below. If you do know what it is, then please try to keep your answers cryptic, so everyone can have a go at working it out. Have fun!

Friday mystery object #457 answer

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

This specimen came to light during some research being carried out on carnivore bones by Dr George Argyros, a Professor visiting us from Emory & Henry College, Virginia. It was identified as Vulpes on the label, but both George and myself were doubtful.

The specimen’s spurious identification can be tracked back to when it was named in the Museum’s register as Vulpes fulva argentata or Silver Fox. This identification was assigned to the specimen when it was given to the Royal Zoological Society by N.H.P. Vickers in March 1900 (see page 127 of the monthly Irish Naturalist covering March 1900):

The Museum bought the specimen in skeletal form from the Royal Zoological Society of Ireland in 1903 and the name Silver Fox was kept until a later review of the taxonomic hierarchy in our database, which ‘corrected’ the name to Red Fox Vulpes vulpes.

However, this name change was not based on the morphology of the specimen. The characteristic lyre-shaped sagittal crest1 immediately made both myself and George think Urocyon and the small size of the specimen made both of us converge on an identification of Island Fox Urocyon littoralis (Baird, 1857) after independent bouts of measuring.

Image of Urocyon littoralis (Island Fox) by Pacific Southwest Region USFWS, 2015.

For those of you interested in seeing the size range parameters for Island Fox skulls, this PDF of the Mammalian Species description of Urocyon littoralis is very helpful indeed.

So I offer a hearty congratulations to everyone who spotted that this skull is from the genus Urocyon, although I think most people were thinking of the Grey Fox, Urocyon cinereoargenteus.

Image of Urocyon cinereoargenteus (Grey Fox) by California Department of Water Resources, 1993.

1It probably shouldn’t really be referred to as that, since it isn’t actually sagittal, except perhaps where the two ridges meet at the very back of the skull – but you know what I mean.

Friday mystery object #457

This week I have a nice skull from the Dead Zoo for you to have a go at identifying:

This specimen came to light as being misidentified when a visiting researcher was taking a look through the collection. We both agreed on what we thought it was, but I’d love to hear your thoughts.

I suspect that this may be easy for some of you, so as ever, please try to keep your answers cryptic, to give everyone a chance to work out what it is. Have fun!

Friday mystery object #456 answer

Last week I gave you this rugged skull, from a rugged place, to have a go at identifying:

As everyone spotted, this is a whale of some sort (what else has a skull that weird-looking?), but the question is, which species?

The location led to a few suggestions of Arctic / sub-Arctic species like Narwhal or Beluga, but they have a much flatter top section of the skull. In fact, those huge vertical lobes of the maxillae seen here is pretty unusual and quite distinctive (even if it is a ittle weathered and broken):

This reminded me of a specimen in the collections of the Dead Zoo and which I had to check, just to be sure of my identification:

As spotted immediately by Chris and not too long afterwards by Adam Yates and Wouter van Gestel, this is the skull of a Northern Bottlenose Whale Hyperoodon ampullatus (Forster, 1770).

This sub-Arctic species has a distribution across much of the North Atlantic. They tend to stick to quite deep water, which makes sense in the case of the specimen I shared from Iceland, since the Reynisfjara beach is infamously dangerous because it shelves off very steeply into very deep water, making the waves that break along the beach behave in an unusual (and frankly terrifying) way.

Occasionally this species will come into shallower waters, in one (somewhat tragic) case a female Bottlenose Whale swam up the Thames (and is now in NHM, London). Our specimen came from an animal stranded on the Irish coast and there are theories that maritime sound pollution is connected to them being driven into shallower waters.

Well done to everyone who worked out which species this skull is from – hope you’re ready for another mystery next week!

Friday mystery object #456

Last weekend, I was fortunate enough to be able to visit Iceland, to witness some of it’s remarkable landscapes.

One location we visited was the infamously dangerous Reynisfjara black sand beach, with it’s “sneaker waves”, which regularly drag people out into the freezing waters.

Something else met its fate on those sands and it’s skull now sits outside the visitor centre. Any idea what it might be?

Worth noting there’s a footprint next to the skull, that gives a hint about the scale.

As always, you can add your questions, observations and suggestions in the comments box below. Have fun!

Friday mystery object #455 answer

Last week I gave you a challenge to get your teeth into:

As I suspected, everyone managed to figure out what type of animal this is, since these teeth are quite distinctive (as mammal teeth often are).

To start with, there are canines and incisors in the premaxilla (the top jaw). These are missing from things like cows, sheep and deer. So it’s not one of them. The premolars are adapted to grinding rather than cutting, so it’s not some kind of pig or carnivore.

The molar teeth are low-crowned, unlike the teeth of grazers like horses which are high crowned, to cope with the wear and tear of silica-toughened grasses. This suggests an animal that browses on softer vegetation. Also, the lophs (those ridges of enamel that join the tooth cusps) are well defined and quite distinctive in their shape. That rules out most other herbivores, including the camels and their relatives.

It turns out that this is a species that I’ve featured on the blog before (although it was almost 11 years ago!) Not a Baird’s Tapir as most people thought, but a Malayan Tapir Tapirus indicus Desmarest, 1819.

I think it’s understandable that nobody got the correct species, since the specimen is a subadult (check out the molar in the jaw that’s still developing) which will somewhat alter the proportions compared to an an adult – especially considering the photos I gave you were restricted to the teeth and missed all the useful features of the rest of the skull.

So well done to everyone who worked out that the teeth belonged to a tapir!

Friday mystery object #455

At the Dead Zoo we get quite a lot of enquiries asking for identifications, and many of these requests are for teeth. Mammal teeth are usually quite distinctive – for instance, tooth morphology underpins a lot of small mammal palaeontology as teeth preserve well and can be identified to genus/species with reasonable accuracy. Additionally, they can often give a good indication of diet.

With that in mind, I took a photo of some teeth that I found in the collections, to see if you can work out which species they belong to:

For the mammal fans among you this is probably way too easy, so please try to keep your answers a little bit cryptic, just so that everyone has a chance to figure it out for themselves. Have fun!

Friday mystery object #454 answer

Last week I gave you this nice robust skull to have a go at identifying:

It proved a little bit more of a challenge than I originally expected, at least in terms of getting a species level identification.

So despite a somewhat ursine (bear-like) overall appearance, that may have confused a few people at first, this has all the features you’d expect to see in a male sea lion. In that it’s big, craggy, has huge open sinuses opening into the orbital region (nobody wants their eyes to be overly pressurised when they’re diving) and the teeth are relatively undifferentiated in the back part of the mouth, but they’re well adapted for fighting up front.

However, it turns out that there aren’t a huge number of resources online to see and compare the skulls of these beasties (and the ones that do exist aren’t necessarily the easiest to navigate). So while almost everyone figured out the sea lion bit, the species choice went a bit off track.

Most people plumped for the Steller’s Sea Lion, which (it must be admitted) looks very similar. But this is actually the skull of a Southern Sea Lion Otaria flavescens (Shaw, 1800).

I talked about this species before on Zygoma (many years ago now), with a specimen from the Horniman Museum, where I provided some links to the Marine Species Identification Portal. Sadly, that resource has been retired, but fortunately Naturalis Biodiversity Centre rescued the content and has kept it available online. It provides drawings of the skulls of both Steller’s and Southern Sea Lions and if you take a look at few key features you’ll spot the differences.

One major indication is the length and shape of the palate. The Southern Sea Lion has a very long palate, which terminates almost in line with the mandibular articulation, whereas the Steller’s terminates further forward. There are a few other features, but that one is the most immediately obvious.

So, a hearty congratulations to a variety of folks on Twitter who spotted that this was the Southern Sea Lion, but there’s no shame in not getting the correct species if you picked Steller’s, given how few resources there are that allow a really good comparison. I hope you enjoyed the challenge!

Friday mystery object #454

This week I’m back onto skulls for the mystery object – it’s been a while! Any idea what this handsome fellow from the Dead Zoo might be?

I’m sure that this won’t pose too much of a challenge for the more seasoned bone geeks among you, so why not try to keep the answers cryptic, so everyone can have a go at working it out. Have fun!

Friday mystery object #453 answer

Last week I gave you this LBJ (Little Brown Job) to have a go at identifying:

This is one of those birds that can be hard to identify in the field when it’s alive, but it can be even harder after spending over 100 years on display in a Museum.

I’ve mentioned this before – when dealing with taxidermy, damage to the pigments in fur and feathers caused by light exposure can significantly alter the colour of a specimen. This it will often happen preferentially – so you might find that black and red is affected more noticeably than brown for example, creating misleading colour combinations. This fading also happens on bills and claws, sometimes changing them to a light brown or yellow.

Another common issue with specimens is that on death the colour of skin can rapidly fade. This means that some common colour features that may be used in identification (e.g. yellow legs) may cease to be reliable. Some taxidermists paint these colour features back in, but some don’t.

All of this adds to the challenge, but when you have an inkling that you’re dealing with a faded specimen you can make some mental adjustments about how to interpret the appearance. This usually means putting greater emphasis on size, shape and pattern of features rather than on colour.

In the case of this specimen, most people narrowed it down to a member of the genus Linaria, but the issue with fading meant that the species that almost everyone opted for was the Twite, whereas the specimen is actually a male Common Linnet Linaria cannabina (Linnaeus, 1758), which I assume is in its winter plumage, unless the fading is REALLY bad (in the summer the males have quite a lot of red on the head and breast). The specimen was collected in Dublin and given to the Dead Zoo in 1915.

A useful feature for distinguishing between the species without relying on colour is the bill, which in the Twite is relatively small. Twites also have heavy streaking of the plumage, which should be somewhat apparent even in a faded specimen. Neither of these are apparent in this specimen.

There is a useful video guide made by the British Trust for Ornithology for distinguishing between Linnets and Twites in the field. It doesn’t extend to museum specimens, but it’s an excellent place to start!

Friday mystery object #452 answer

Last week I gave you this guest mystery object from the comparative anatomy collection of the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne, courtesy of Rohan Long:

Image by Yijie Cheng, 2023

This is one of those specimens that it can take a while to get your head around, as most of the key features are entirely missing. From the top, the skull almost looks mammalian. Perhaps a little like a large rodent missing part of its zygomatic arches:

Skull of a Striped Ground Squirrel

Even from the side there are some similarities, although it looks a bit more like a turtle:

Image of mystery bones by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Skull of a Loggerhead Turtle

If you look closely at the underside of the skull, you’ll notice that it has a single occipital condyle, which is something you see in reptiles and birds, but that view of the underside also becomes clear that the front section of the mystery object doesn’t taper to create a bill, like you’d see in a turtle:

Image by Yijie Cheng, 2023

In fact, a bill is the most diagnostic feature that’s missing, and that’s because it’s fallen off.

Those cervical vertebrae are quite distinctively avian – and from a long-necked avian at that. Once you realise that this is the braincase of a fairly large long-necked bird, the next task thing is to look at birds with a bulbous and cleft region on the head, just at the base of the bill (most bird skulls taper down to the bill).

For me that indicates one species above all others – the Mute Swan Cygnus olor (Gmelin, JF, 1789).

Mute swan skulls “Cygnus olor”. Technique of bone maceration on display at the Museum of Veterinary Anatomy, FMVZ USP.

I’d like to offer a hearty ‘bravo’ to Adam Yates, who was the first to comment and correctly identify this with a great cryptic clue:

It is an anseriform for sure the large oval basipterygoid articulations are a give away. With that profile, i’d lose my voice while trying to say the name of a certain Western Australian River.

Adam YatesJanuary 20, 2023 at 8:45 am Edit

This was backed up the ever-knowledgable Wouter van Gestel who runs SkullSite, which is the single most useful online resource I know of for bird skull identifications. Speaking of useful online resources, Rohan has been working on a project to make the collections of the Harry Brookes Allen Museum of Anatomy and Pathology available online – so be sure to check it out!

Friday mystery object #452

This week I have a guest mystery object for you to have a go at identifying, courtesy of Rohan Long:

Here’s another specimen from the comparative anatomy collection of the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne.

I have identified and documented almost the whole collection of almost 500 specimens, except for a few dozen that I have so far been unable to identify – the “box of shame”. These specimens mostly comprise fragmentary or isolated elements.

However, one of these problematic specimens comprises a partial skull articulated with four cervical vertebrae. Despite these particular skeletal elements usually enabling ready identification, this specimen has confounded me for months. I have had various hypotheses as to whom the skull could belong to, but nothing has been quite right.

I have googled images, I have visited our zoology museum, I have looked at books, and I have not been able to find the identity of this skull. Can you solve this osteological enigma? 

Image by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Image of mystery bones, by Yijie Cheng, 2023
Image by Yijie Cheng, 2023

By the way, we have a brand new online database where you can explore our comparative anatomy specimens, along with our other public collections. It’s the first time in about a century that this significant collection has been accessible to people outside of our Anatomy Department.

I think I may know what this is, but both myself and Rohan would love to hear your thoughts!

Friday mystery object #451 answer

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

In the ornithological community, birds like this are sometimes referred to as an LBB / LBJ (Little Brown Bird / Job), because they are small, brown and hard to identify (especially in the field) due to the large number of similar looking species.

This specimen has a robust, conical bill and grey-streaked breast, which led some of you to think it could be a juvenile Crossbill or perhaps a female Grosbeak. However, as indicated by Wouter van Gestel in an excellent cryptic clue (and by Tim Dixon in a rather rude one), this is a Corn Bunting Emberiza calandra Linnaeus, 1758. It was collected in County Dublin and donated to the Dead Zoo in 1880.

These seed-eating passerines were widespread in arable farmland across Ireland in the 19th and early 20th centuries. However, changing land use practices reduced the available habitat until they became locally extinct as a breeding species in the late 1990s – well within living memory for many people.

The Irish name for the Corn Bunting is Gealóg bhuachair and an interesting fact about these birds is that their populations are remarkably sedentary, allowing them to develop unique dialects in their breeding area. This means that even if this species is reintroduced to Ireland – assuming farming practices become better suited to their survival – the landscape will never again ring with quite the same song that these birds would have sung in the past.