Last week we had a guest mystery object from Rohan Long, Curator of the Harry Brookes Allen Museum of Anatomy & Pathology at the University of Melbourne:
It is not an easy one. This part of the mammalian skull contains very few helpful diagnostic features – as pointed out by Kenny Travouillon:
Plus this is from a juvenile animal, and we all know how that can cause problems when making an identification.
Thanks to everyone for your comments – Rohan was keeping and eye on them here and on Twitter, so I’ll hand over to him to wrap this one up:
Well, it’s been a week, and many identifications for the mystery skull were offered on Twitter and in the Zygoma comments. Some suggestions were silky anteater, marsupial mole, pangolin, armadillo – but the focus quickly turned to marsupials. On Twitter, mammal curator Kenny Travouillon said it was not peramelemorphian or macropod, zooarchaeologist Jillian Garvey said that it could be macropod. Early on, biology lecturer Robin Beck said that it was definitely a phalangerid, and that it was probably a juvenile common brushtail possum (Trichosurus vulpecula). Robin identified the specimen as phalangerid based on the restriction of the mastoid exposure to a ventral strip on the occiput, and then narrowed down to trichosurine, rather than a phalangerine, due to the relatively flat dorsal profile of the skull. The bone texture indicates a juvenile specimen. (Richard came to the same conclusion in the Zygoma comments.)
I went digging around in our comparative anatomy collection to investigate this and then clouded matters a bit, as I found a partial skull of a juvenile common ringtail possum (Pseudocheirus peregrinus) which was superficially similar to the mystery skull. I thought this was the real identity of the skull, but Robin pointed out that the ventrally restricted mastoid exposure, more recessed stylomastoid foramen, and a well-developed pterygoid fossa all point to Trichosurus rather than Pseudocheirus.
I think this partial skull is conclusively identified to genus. I have already identified a number of (less ambiguous) Trichosurus specimens within the comparative anatomy collections. Although it would take more work to definitively ID the species, I think it is likely to be vulpecula – a very common and widely distributed species in Australia. As you may have noticed from the original images, the specimen has sand grains adhering to it. Based on this, I’d say that this was collected in the field, probably by Frederic Wood Jones (or members of the McCoy Society for Research and Investigation, which he founded) in the 1930s.
Thank you all for your suggestions and discussion!
Finally, I’d like to add my thanks to Rohan for giving us this mystery object to mull over. If anyone else fancies doing a guest mystery object, please do get in touch.
This week I’m delighted to have a guest mystery object for you, presented by Rohan Long, Curator of the Harry Brookes Allen Museum of Anatomy & Pathology at the University of Melbourne (who is on Twitter as @zoologyrohan) and photographed beautifully by his colleague Gavan Mitchell:
This is a skull from the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne. Although the focus of our museum is on human anatomy, we have a significant comparative anatomy collection, which comprises hundreds of specimens of vertebrate animals – skeletal material, skulls, and potted specimens. Occasionally, I’ve encountered animal specimens that are very difficult to definitively ID, and this partial skull is one of them.
Our comparative anatomy collections date from the earliest 20th century and are predominantly native Australian mammals and domestic animal species. However, the academics at the University have always had international networks, and there are species represented in the collection from all over the world. Many have been prepared in a lab for class specimens, many have been collected in the field. The latter are assumed to have been associated with Frederic Wood Jones, a British anatomist with a fondness for comparative anatomy and island collecting trips who was head of our Anatomy Department from 1930 to 1937.
Do you have any ideas what this portion of skull might be from? I don’t think we need cryptic answers for this one. Rohan will be keeping a close eye on the comments, so do feel free to ask questions.
Last week I gave you a nice skull to have a go at identifying:
It proved to be more tricky than I thought, but I think that may be because there is a skull image on Wikimedia that may have misled people searching for a comparative skull of this species.
This is the skull of the humble Guinea Pig Cavia porcellus (Linnaeus, 1758), but if you tried searching for Guinea Pig skull, you may have seen this image:
Clearly this is not the same species as our mystery object – the incisors alone are an absolute give-away, with their striking orange enamel and the their much greater size. Those big incisors also bed deeply into the mandible, creating a pronounced ridge at the base of the mandible that props the entire skull at an angle. This one is the skull of a Coypu, regardless of the Guinea Pig identification given on the Wikimedia page.
There were also quite a few suggestions that the mystery object might be a Capybara, or one of several other South American rodents. The size suggests it’s not Capybara – I suppose a very young Capybara might just about be small enough, although they would certainly have less pronounced muscle scars and more open sutures.
There are plenty of other South American rodents, but most of those of a similar size and overall shape have a much more V-shaped exit to the nasal passage in the palate, rather than this very open and U-shaped structure.
Last week I gave you this beautiful, but rather enigmatic bird of prey as a mystery object:
It was a bit of mean one, because it’s not a natural species, which meant almost everyone was driven to distraction by the subtle differences from anything readily recognisable. I say almost everyone, because Pete Liptrot got it spot-on:
This is indeed a hybrid falcon, that was hatched in Co. Galway to a Saker Falcon Falco cherrug Gray, 1834 mother (called Farah) and Peregrine Falcon Falco peregrinus Tunstall, 1771 father back in 1971, marking the first example of this cross.
The specimen was donated to the Dead Zoo in 1976 by the Rt. Hon. Johnny Morris – who by all accounts was as interesting and unique as the bird he reared. Sadly, I heard that Johnny passed away recently, which will doubtless be a blow to the many people he met.
Last week I decided to give you a taste of the kind of identification I often get asked to do. One bone with no scale and a photo from just one angle that doesn’t quite show what you’re looking at very clearly:
I must admit that I was suitably impressed with the responses though, since the very first response by Chris was cryptic yet absolutely spot-on.
As you probably figured out, this is the upper front section of jaw (or premaxilla if you’re feeling fancy) from a fish.
The more difficult bit is working out which fish, since there are plenty to choose from – over 28,000 species.
This is where knowing where the specimen came from can be helpful, since it can help narrow down the likely possible options. However, morphology is always the most important thing to consider and I find that locality is more useful for figuring out species than the higher taxonomic group – and higher taxonomy is really helpful for narrowing down options.
Of course, to do this you need good comparative morphological specimens to help steer you in the right direction. This can be difficult when working with fish, since there are so many species and they have skeletons that tend to be poorly fused, so there are many separate bony elements for each animal.
The premaxilla isn’t always the easiest element to differentiate, but there are a few things to look for:
The teeth. You do need to be careful with these as a feature, since they can break off and look quite different between individuals. Check out the teeth in this specimen and notice there is a line partway down each tooth. This is a weak point that the teeth can break along quite easily and I’ve seen examples of premaxillae from this species that have mainly squarish, blunt looking teeth because the sharp cusps have come off.
General shape. Some Orders of fish have premaxillae that are almost solid triangles (like the Tetraodontiformes), others are long, thin and quite straight – looking almost like just a shard of bone (like some Beloniformes). It’s worth taking a good look at the shape and trying to spot processes and articulation points, since these provide clues to the taxonomy.
Processes on the rear of the premaxilla. These can be present or absent, well defined, poorly defined, high, low, long, short, simple, complex etc. The thing to remember about this mystery specimen is that the rear of the premaxilla curves downward with no processes on the upper surface – so its close relatives are also unlikely to have processes, or if they have them they are unlikely to be well-developed.
Processes in the middle of the premaxilla. Some groups have a process like a fin in the middle of the premaxilla (e.g. Esociformes and Osmeriformes). The mystery has no process here.
Processes on the front of the premaxilla. Many groups do have at least one process on the upper surface at the front of the premaxilla, but the number and shape are important for identification. The mystery specimen has two – the first is tall and shaped a bit like a bat-ear the second is not fully separate from the first and it is lower and quite squared off:
When you start to put all of these features together it becomes easier to narrow down possibilities. If you use Osteobase to scan through images of premaxilla you’ll find that the premaxillae that are closest (although none are identical) are from the Pleuronectiformes – or the Flatfish.
Knowing this one is from Irish waters (which I admitted in the comments) helps narrow down options to 22 species (things like Turbot and flounders) and with a bit of searching online and especially checking specimens in the Archaeological Fish Resource at the University of Nottingham you can narrow down the possible species to one good option.
This is the premaxilla of a Halibut Hippoglossus hippoglossus (Linnaeus, 1758). These large flatfish undergo a strange developmental distortion of the head that allows them to lie on their side on the seabed without having their left eye sitting in the sand.
This asymmetry is far more obvious in the whole animal than it is when just looking at the skull.
As you can hopefully make out, the jaws are reasonably symmetrical and the distortion is mostly in the area of the frontals and ethmoid bones, which have shifted to allow the eye to move. Here’s a more complete view of the right side of the Halibut skull to finish up with:
One of the things I get asked to identify a lot in my job are bits of bone that people have found on the beach. I’ve decided to give you an idea of what that’s often like, with this small section from a skull as this week’s mystery object:
I hope you have some fun figuring out what this bone belongs to – I usually find it to be quite a rewarding experience.
As ever you can pop your thoughts in the comments box below. Enjoy!
I hope that you had a very merry festive season and that you didn’t spend too much time contemplating last week’s mystery object from a dig by Irish Archaeological Consultancy that’s been taking place in Dublin:
Because the object is still partly in the soil and I was unable to get images from every angle and I think that there are some helpful features still buried, so I apologise for that. Still, we can take a look at what we know and start narrowing down possibilities.
First of all, we know that this is the lower part of the hind limb of a bird. That much is clear due to the shape of the articulations, in particular the lobed shape of the distal end of the tarsometatarsus (or TMT, which is the long bone in the image that is intact apart from a hole in the midshaft).
There are birds common to Ireland which are smaller, but with longer legs, such as the Grey Heron. However, their TMT would seldom be greater than 210mm. Even the Common Crane, which has historcially be reported in Ireland, only has a TMT in the 200-250mm range – about the same as a Greater Flamingo, which is the kind of exotic bird that may have been brought to Ireland by humans as an ornamental in the last few hundred years. We need to look further afield.
The next obvious stop has to be the largest bird, to at least get a sense of just how big the TMT is likely to get. Ostriches have a TMT in the region of 448mm, so we’re not quite up to that size, but we’re also not all that far away. On a side note, as we mentioned earlier, the mystery object probably still has part of the distal articulation buried in the soil – but if it didn’t then it would be a good contender for a small Ostrich, since they only have two toes and their TMT would be missing the section of articulation that is likely buried here.
Based on size alone this suggests that Emu is the most likely option, but we all know how size can be a bit unreliable. The next thing to look at is probably the shape of the unguals (those are the ends of the digits where the claws would attach):
In most ratites the ungual on the middle digit seems to have quite a flat profile, but from the images I’ve seen of skeletons, the Emu appears to be the only one with a similarly curved middle ungual.
On balance (and I’d be happy to reconsider if I can get my hands on the fully excavated specimen) I think this is most likely to be the leg of an Emu Dromaius novaehollandiae (Latham, 1790) – an opinion shared by Adam Yates.
I realise there are some other extinct large ratites (various moas and the elephant birds) that may have found their way to Ireland as fairly complete fossils, but the lack of holes for wiring, and with the bones still in their correct orientation suggests that this specimen went into the ground with its skin still more or less intact.
I’d like to thank everyone for their suggestions – I’m not sure I’d call this a cut-and-dried answer, but hopefully I’ll get a chance to take a closer look at the specimen in 2022 and confirm the identity with more certainty.
This week I thought it would be nice to have something seasonal and festive for Christmas Eve, but I couldn’t think of anything that I haven’t done before, so you’re getting a genuine mystery object that came to light on an archaeological dig in Dublin by Irish Archaeological Consultancy:
I’ve been thinking about a possible identification for this specimen (and I’ve ruled out a LOT of possibilities), but I’ve not had much time to check on comparative material, so I’d be keen to hear your suggestions about what you think this leg might have come from in the comments below.
Have a Merry Christmas and try not to spend too much time thinking about this 😉
Last week I gave you this fishy looking critter to identify:
It wasn’t an overly difficult one for most of you, since it is a very distinctive and somewhat unusual animal with some immediately recognisable features. Most obvious are the gills.
Bony fish only have one visible external opening on either side of their head where water exits after it’s flowed over the gills, and this is well hidden when the gill flap (or operculum) is closed. So this is clearly not a bony fish.
Most modern sharks have 5 external visible gill slits, but this one has six. That makes it a bit of an evolutionary anachronism. There are only seven species of shark with more than 5 gills and they are all in the Order Hexanchiformes, which narrows down the possibilities considerably. Of those, two have seven gills, leaving just five possible species.
Those five species sit in just two families – the Cow Sharks and the Frilled Sharks. These can be separated based on a variety of features, but the most obvious is that the Cow Sharks have fusiform (or spindle-like) body shapes with a very pointed nose to help them move efficiently through the water by minimising drag. The Frilled Sharks have more anguilliform (eel-like) bodies with a blunter head and mouth set further forward in relation to the eyes – a feature about the mystery object picked up on by Allen Hazen.
There are only two species of Frilled Shark to choose between and I’m not sure I could tell the difference between them based on the photo provided. However, one species is only found off the coast of South Africa, and in last week’s post I dropped a (hopefully) helpful clue – this specimen was caught off the coast of Ireland.
That means this can only be the Frilled Shark Chlamydoselachus anguineus Garman, 1884. Well done to Adam Yates for being the first to get it spot on. This specimen was caught off the coast of County Donegal at a depth of 390 fathoms (or 713 metres in standard units) just over 21 years ago. A special mention to Pete Liptrot on Twitter who managed to identify this mystery object to the actual specimen – not just the species!
This week I have another fishy specimen for you to have a go at identifying:
This one was caught in deep water off the coast of Ireland and is preserved in one of the large fluid tanks behind the scenes in the Dead Zoo. If you recognise the species maybe drop a hint in the comments box below. Enjoy the challenge!
Last week I gave you this rather fishy looking mystery object to have a go at identifying:
With that prominent lure it was fairly obvious to everyone that this is an anglerfish of some sort, but there are somewhere in the region of 286 different species, so it needs some narrowing down.
That bulbous body shape is pretty distinctive though, so a lot of people both in the comments and on Twitter quickly identified this as one of the football fish in the genus Himantolophus.
Narrowing down to species is perhaps a bit tricky from just this photo. There are 22 species in the genus and thanks to the deep sea habitat these fish inhabit they aren’t commonly seen, so photos for comparison can be hard to find.
However, the double bony ridge on the head (that makes it look like it’s frowning) is very prominent in this specimen, which isn’t the case for all of the football fish species. However, it is particularly notable in the Pacific and Atlantic Football Fish species.
I have to admit that I’m just not good enough with fish identification to tell the difference based on specimens I’ve seen. However, since this specimen is in the Dead Zoo in Dublin, it seems unlikely (although not impossible) to be from the Pacific.
In the words of our youngest commenter:
It is indeed an Atlantic Football Fish Himantolophus groenlandicus J. C. H. Reinhardt, 1837, so very well done to E and everyone else who managed to work it out!
As I suspected, quite a few people recognised this specimen. It’s a humerus with the distal articulation (that’s the elbow bit) intact and the proximal articulation (where it meets the shoulder) broken off.
The size and overall shape is similar to a small, robust human humerus, so at first glance it might suggest a primate, like a Chimpanzee or maybe a small Orangutan. However, the olecranonon fossa (the groove at the back of the elbow joint that the olecranon process on the ulna bone of the lower arm/forelimb locks into when the arm/forelimb is straight) is far too deep for it be from an ape.
Baboons, Geladas and Mandrills have a deep fossa, but the overall shape of their articulations is more cuboid than this, so there aren’t really any other primates large enough.
The shape is all wrong for an ungulate and most carnivore humeri have a different articulation shape and some diagnostic features that are lacking here. But, there is one type of carnivore that has a humerus this shape. This was not lost on many of you, both in the comments here and on Twitter.
The general similarity in shape with a primate humerus is due to a functional similarity in the use of the fore limbs. Unlike most carnivores, the animal this came from can stand bipedally and use its arms. Obviously I’m referring to a bear of some kind.
The type of bear is a bit harder to pin down definitively. It’s unlikely to be a Brown Bear, since it’s not really big enough. That also rules out Polar Bear. I think it’s most likely to be from an American Black Bear Ursus americanus Pallas, 1780, since the other species of a similar size have somewhat better developed supracondylar crests (the ridges on the sides that the muscles of the forearm attached to) it could be from, like the Asiatic Black Bear or Sun Bear.
Thanks for all your observations on this – I hope there will be some more exciting archaeological mysteries to come!
You can’t tell from the photo, but it’s very dense and heavy. What you can see is that it has some quite well defined longitudinal ridges:
This isn’t something you normally find in horns, but you do find in tusks. So the question has to be, what kind of tusk is this?
I’ve talked about tusks before on this blog, and I’ve spent a lot of time identifying ivories over the years, after learning key diagnostic features from the wonderfully knowledgable Dr Sonia O’Connor, both in her training courses and working alongside her when I was at the Horniman Museum and she was visiting to do some research. This tusk reminds me of one of the more tricky ones we looked at.
The marine location suggests it could be from a Walrus. The overall shape isn’t bad, but Walrus tusks tend to be no more that about 75cm long at their longest. They also have a more squared-off section at the base and often a deeper groove on the sides partway along the length from the base, so it seems unlikely.
Really that just leaves something proboscidian – but here we hit the difficult bit. Mammoth tusks have been dredged from the sea many times, from fossils in sediments that became covered by sea level rises after the melting of glaciers around 11,500 years ago. However, Elephant tusks were transported in huge nubers to Europe by ship to supply the demands of the ivory trade between the late 18th and early 20th Century, so it is entirely possible that this is a relic of that trade (as suggested by Chris Jarvis).
In my experience, submerged Mammoth tusks are seldom in such good condition as this. While there is some degration and flaking towards the tip, there is much less of the deep staining or separation of dentine fibrils that I would normally expect from Mammoth tusk submerged for several thousand years.
However, if it was more deeply buried until recently it may have avoided the worst of that degradation, so that expectation isn’t good enough.
There is a method for distinguishing between Mammoth and Elephant ivory, that relies on an artefact of the tooth development process. This involves measuring the intersection angle of Schreger lines (an optical feature resulting from light interacting with dentine tubules) in a polished section of the tusk:
In Elephants the angle of intersection tends to be obtuse (>90o), whereas in Mammoths they are more acute (<90o). Of course, to see this would require cutting a section of tusk, so it may have to remain a mystery until the desalination treatment has been completed and I can see if there is an opportunity to check any broken surfaces or prepare a small sample.
The question in this case has to be, how important is it to know the identity, compared to the importance of keeping the specimen as intact as possible? That is a bigger conversation that will need to be had with my colleagues.
This week I have another real mystery object for you to have a go at identifying. This was dredged off the sea floor, on the extreme western edge of the European continental shelf where it meets the Atlantic Ocean:
There are a few possibilities, so I’d be interested to hear what you think. You can leave your suggestions, observations and questions in the comments box below.
Last week I gave you a genuine mystery object from an archaeological dig in Dublin to have a go at identifying:
There were several suggestions, both in the comments here and on Twitter. They can’t all be right, so this seems like a good opportunity to look at the skulls of a variety of different species, so we can narrow it down.
Scale is important in this, since the mystery object is quite large, despite being just a section of the braincase from the rear of the skull, made up of parts of the parietal bones (on either side) and part of the occipital bone (the bone that forms the back wall of the skull). This is an area of convergence on the skull – a meeting point for the bony sagittal crest associated with attachment of the temporalis muscles (used in operating the jaw) and the nuchal crest associated with the nuchal ligament that connects the trapezius muscles of the neck (used in moving the head) to the skull.
Cervids lack the well-developed sagittal crest seen in the mystery object. They also have a broad triangular scar for the attachment of the nuchal ligament – presumably relating to the high forces that the nuck muscles have to deal with due to the carrying of and fighting with antlers. In females the shape of the nuchal scar is very similar, although it’s less well defined. So the mystery, with its strong sagittal crest and neat occipital crest is not from a deer.
Sheep, cows and other bovids are similar to deer – with a broader nuchal scar (presumably for similar reasons to the deer). Their reliance on masseter muscles more than the temporalis muscles when chewing also means that their sagittal region doesn’t match our mystery critter, with the temporalis scars usually not meeting the midline of the skull:
In profile the pig skull looks like a pretty good match, with scars from quite well-developed temporalis muscles just behind the eye socket:
But the Suidae actually have a very distinctive spatulate shape to the rear part of their skulls, presumably for incredibly hefty nuchal ligament attachment to help power their rooting activity:
That results in a very distinctive shape in the dorsal view, so the mystery object is clearly not a pig:
Horses can have a fairly well-developed sagittal crest and I don’t feel like I can entirely disregard the possibility that this mystery specimen may be from a mature Equid, although the shape looks somewhat off to me – a bit flatter and angled more downwards:
The horse specimens I’ve seen also have more of a nuchal ‘knot’ rather than a defined ridge in the midline of the occipital:
Camels have very strongly developed sagittal crests, but this is parly due to the short and narrow area to the rear of the braincase, so the crest rises sharply. The nuchal crest is also much more prominent, forming a continuous sharp line right into the zygomatic arch:
The mystery object could be from a camel, but I think it lacks the strength of the camel’s nuchal region and the braincase seems broader than that of the camels.
There was a suggestion of badger, but that can be ruled out simply because of the size. This section of mystery bone is about as long as a badger’s entire skull:
While the size is off, the suggestion does have merit in terms of morphology, as the broad braincase does hint at a member of the Carnivora and in Ireland there aren’t many large carnivores – at least not any more.
One type of large carnivore still found around Ireland would be the seals. However, the need for extreme flexibility in their head movements while resisting drag from their watery environment gives them a very characteristic shape to their nuchal region:
Dogs are always worthy of consideration in these instances. They can be small or large, their skull shape can vary hugely and they are found everywhere that humans are found.
This does seem a bit more like it, although size is still an issue. Even the biggest dog – and the skull shown above is from a BIG dog – struggles to be close to the right size. Also, the nuchal crest in dogs tends to taper to a point fairly evenly, whereas the mystery bone has a nuchal crest that has ‘shoulders’ for want of a better term. Dog is possible, but I’m not convinced.
There is no way a domestic moggie could come close to big enough, but there are big cats that come surprisingly close:
The nuchal crests of lions and tigers have those ‘shoulders’ and a well defined occipital crest down the midline. They are also closer in size and the braincase and sagittal crest are about right.
Of course, we can’t talk about lions and tigers without also considering bears.
Again, the nuchal crest ‘shoulders’ are there, the size is perfect and the sagittal crest and braincase are close. However, the occipital crest seems a little less well-defined.
So these are the species I’ve been considering and at the moment I’m thinking big cat or bear for this mystery object. I know there are other large carnivores, like hyenas, but they have an unmistakable sagittal/nuchal region:
I will need to have the specimen in my hand with a good range of comparative specimens available to get a more conclusive identification. One significant factor will be that as animals mature, their muscle scars tend to become more rugged and this changes their appearance, so I will need specimens from animals of different ages and life histories to help consider those factors.
Sorry I’m not giving you a definitive answer this week, but I hope you’ve enjoyed the process!
This week I have a very real mystery object for you to have a go at identifying, that was recently excavated in Ireland by archaeologists from Irish Archaeological Consultancy and they very kindly let me take a look and share it with you:
I have an idea of what this is, but I’d be keen to hear what you think it might be.
You can put your thoughts in the comments below and hopefully between us we’ll figure it out!