This is one of those species that I have a bit of a soft spot for, due to the general weirdness of the skull. That does however make it quite recognisable as a specimen, even in a photo that hasn’t been taken for the purposes of identification – like this one.
Everyone who commented recognised that this is some sort of turtle, and thanks to that very flat skull with all the features towards the very front end, most people worked out that it’s a from a Mata-mata Chelus sp. Duméril, 1806.
Any extra information is useful when trying to identify fish, since there are so many species, but sometimes a bit of familiarity is what you really need to start narrowing down options, which makes the Zygoma community a helpful resource when dealing with an identification like this. And you did not disappoint!
Tony Irwin, jennifermacaire and Wouter van Gestel all came through with excellent observations on the species. This object is a neurocranium (we’ve talked about these before) with a very pronounced supraoccipital crest (the big fin-like crest on top), which combined with the overall shape of the neurocranium suggests it’s a member of the Sparidae (the family containing the Porgies and Seabreams).
Knowing this, and having the Fishbase list, makes it much easier to narrow down the likely species. Unfortunately, there is no single resource to make comparison easy, but a lot of trawling through a variety of images of skulls and neurocrania will yield results (Flickr has some useful images for example).
From my searches, the shape of the supraoccipital, vomer/prevomer (the beaky-looking bit) and that impressive set of supraorbital crests (those frills of bone above the eye sockets) suggest that this mystery object is probably the species suggested by Tony Irwin – the Gilt-head Seabream Sparus aurata Linnaeus, 1758. I’m not 100% sure of this identification, but it’s the best fit I can find.
Thanks to Paula for sharing this object and thanks to eveyone for your thoughts on this specimen – it’s always valuable to get your input!
This week I have another guest mystery object for you to have a go at identifying, this time it’s from Paula Burdiel, who found the specimen in summer 2020 while beachcombing in Islantilla, Huelva (Spain):
With this fantastic array of images and clear locality information, I’m hoping that we can figure out which species we have here. Let’s hear what you think it might be in the comments below – between us I think we can identify this fishy mystery object!
The teeth tell us that the mystery object is from one of the Cercopithecidae (Old World Monkeys) since there are only two premolars instead of the three that you find in the Platyrrhini (New World Monkeys). That helps a bit, but there are still over 150 species in the Cercopithecidae to consider.
Some can be ruled out fairly easily, such as members of the Papionini, like baboons and macaques, which have adults that are more prognathic (their jaws jut forward) that this specimen. This is less true for juveniles (jaws jut more as the animal grows and matures), but we can ignore that here, since the mystery specimen has well-fused sutures and visible wear on the teeth, so we know it’s an adult.
One thing that can be useful to consider when trying to identify primate skulls is the shape and position of the nasal opening. This can vary within species and it can be a feature sensitive to the angle at which a photograph is taken (making it more difficult to assess from images), but overall it can help narrow down possibilities without having to get into too much fine detail early in the identification process.
The Mammalian Crania Picture Archive has well standardised images, including a reasonable variety of primates with males, females and animals of different ages represented. They also provide some measurements for each specimen, that may be useful when making comparisons. The primate page is here in case you’re not familiar with this very valuable resource.
Over the last week I’ve taken a look through a wide variety of skulls from different primate taxa and I’m confident that the mystery specimen is from the Colobinae. I think the position of the nasal opening (especially the top part of the opening in relation to the eyesockets) is helpful in distinguishing possible species within the subfamily. This makes sense when you consider that a third of the genera in the Colobinae are in a group known as the “odd-nosed monkeys”.
In this specimen the nasal opening forms a shield shaped hole with a flat top that starts quite high in relation to the eye sockets. In most species it starts lower, sometimes well below the line of the bottom margin of the eye socket. The Red Colobus is superficially quite similar, but when you look at other features it doesn’t look right – for example, if you look at the underside of the skull it has several different features, include a differently shaped incisor arcade and the pterygoids (the wing-shaped bits of bone that spread to either side, just behind the palate) are a different shape.
However, I did find a species which matches much better, so I am tentatively suggesting that the mystery object may be a Black-crested Sumatran Langur (AKA Mitred Leaf Monkey or Sumatran Surili) Presbytis melalophos (Raffles, 1821). If not that species I think the mystery specimen will be in the same Genus. There will undoubtedly be additional species with similar skulls that I’ve not seen, but within the limits of the resources at my disposal I don’t think I can do any better than that.
My thanks to everyone for your suggestions and many thanks to Rohan for sharing this mystery object. It’s been an interesting one and has reinforced my conclusion that primate skull identification can be REALLY difficult!
This week we have another guest mystery object from Rohan Long:
Today’s mystery object is another item from the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne. In contrast to our last offering – a partial skull with most of the diagnostic features frustratingly absent – this is a full skeleton of a small primate. We have many classroom sets in our collection comprising complete, disarticulated skeletons of mammals, mostly marsupials and primates. The primate sets overwhelmingly consist of macaques (Macaca sp.) which I presume were lab animals from the University. Additionally, there are sets of a few baboons, a few chimpanzees, and one Sacred Langur (Semnopithecus entellus). Then there’s this one.
I had originally described it as, “large macaque”, but after cataloguing dozens of macaque skeletons, it stood out as something different. It kept bugging me, and I had committed myself to giving every specimen in our comparative anatomy collection a proper identification. I had found some previous blog posts by Paolo while researching how to identify primate specimens, and that’s what prompted me to initially get in touch. In regards to provenance, our comparative anatomy collection was mostly amassed in the early 20th century, and many specimens are associated with Frederic Wood Jones, Anatomy Department Head from 1930-1937. Wood Jones and his colleagues had strong international networks, and there are species in this collection from all over the world.
As ever you can leave your observations, thoughts and suggestions about which species this might be in the comments section below. Have fun with this one!
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 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:
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!
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 this rather nice skull to identify:
I was hoping that it would catch some of you out, since at first glance it looks like the skull of some kind of canid. I thought I had caught out Joe Vans, but then he noticed one of the features that sets this skull apart from dog skulls – the pinched-in section in the mid-muzzle area. Then everyone started piling in with their observations and my hopes of being tricksy were fully dashed.
This is of course the skull of that paragon of convergent evolution, the Thylacine (AKA the Tasmanian Wolf or Tiger) Thylacinus cynocephalus (Harris, 1808).
These physical differences between the Thylacine and the Eutherian canids are features common to many marsupials and they act as reminders that evolution is limited by what it has to work with. At the most fundamental level that means DNA.
In recent years the methods for successfully extracting and sequencing DNA from museum specimens has moved on in leaps and bounds. In 2018 these advances allowed the Thylacine’s genome to be assembled, allowing comparison with their morphologically similar, but taxonomically distant counterparts.
The team that did this went looking for similarities between protein coding genes in the different lineages at first, to understand what was driving the morphological convergence – but it seems that they were looking in the wrong place.
When they looked more closely, it was actually in the cis-regulatory elements (the non-coding DNA that used to be considered “junk”, but which is now recognised as playing a vital role in regulating development) that genetic convergence was seen. It turns out that these elements were also driving convergence in brain development between Thylacines and canids.
After last week’s foray into insects, I have a nice chunky vertebrate skull to for you to have a go at identifying:
Any idea what this might be from? I have a feeling this may be way too easy for some of you, so let’s keep the answers cryptic or perhaps poetic, so everyone gets a chance to figure it out for themselves. Have fun!
Last week I gave you this (somewhat dusty) mystery object to try your hand at identifying:
I know that insects aren’t a frequent occurence on the blog, so this was a bit of an unfamiliar one for many of the regular Zygoma commenters. Of course, that didn’t prevent some astute observations.
Chris Jarvis immediately spotted that this is a wood wasp or sawfly, while palfreyman1414 flagged that it looks more like a fly (barring the long ovipositor). That’s because wood wasps, despite being members of the Hymenoptera, lack that characteristic wasp-waist that makes the Apocrita (the hymenopteran Suborder containing wasps, bees and ants) so distinctive.
The Symphyta is the Suborder containing the sawflies and there are thousands of different species. However, narrowing it down wasn’t really that hard, since sawflies specialise in using their ovipositor to lay eggs in the stem of quite specific host plants and the only sawflies in this size range are in the family Siricidae, which are the ones that pick on trees (which is pretty interesting, since they form a symbiotic relationship with wood-digesting fungi in order to feed on wood as larvae).
Of course, being insects, there are still around 150 to choose from, but between ruling out taxa that have adopted Batesian mimicry and those that are a very different size or shape, it becomes easier to narrow down the possible contenders – especially when you consider that this one turned up in Dublin, Ireland (although as pests of wood they can emerge from pine timbers a long way away from their point of origin – this one probably got into the Dead Zoo in some of the timber being used for our big decant project). The best fit for this specimen lies in the Genus Sirex.
When tryingto to distinguish between members of Sirex it’s important to pay attention to colour details of the legs and antennae. In this case it has red legs and black-and-red antennae. If you spend a while checking through the very helpful Sawfly GenUS resource you’ll find that the best fit for the mystery specimen is a female Sirex juvencus (Linnaeus, 1758).
Of course, the entomologists out there managed to figure all this out without any problems, both on Twitter and in the comments.
So well done to Jaswinder and Russell Stebbings for getting a species level identification – I would say that you got it right, but since I’m not an entomologist I think I should just be pleased that your more informed opinions happen to support my best guess. Thanks!
Stay tuned for another mystery object next Friday. Have a great weekend everybody!
*not a Bug – the True Bugs are Hemiptera and have nothing to do with this.
Last week I gave you this specimen from the “Unidentified” drawer in the collections of the Dead Zoo to try identifying:
I don’t think anyone had much difficulty in identifying it, since it is quite a familiar and characteristic skull, but well done to everyone who worked out that this is a European Badger Meles meles (Linnaeus, 1758).
There are two other species in the same genus – the Asian Badger M. leucurus and Japanese Badger M. anakuma, so they also need consideration (skulls of all three species can be seen in this paper by Andrey Puzachenko). However, the Japanese Badger is a smaller and more delicately skulled animal and the Asian Badger can be distinguised by differences in the shape of the region around the bony bulbs that hold the ear bones (called the auditory bullae – in Asian Badgers they’re more obtuse and have a straighter lateral margin).
So apart from the distinction between two members of the same genus, this is a fairly straighforward specimen to identify, it makes me wonder why it wasn’t recognised in the collection? I think there are a couple of factors, which I’ll outline here.
The first is that the lower jaw (mandible) is missing. This is totally normal for almost any kind of animal skull you find, except these badgers, which have a well-developed bony process that locks the mandible into the long jaw articulation (known as the glenoid fossa).
Badger skull with mandible locked in place.
Detail of jaw articulation showing the main features. Red = mandibular articulation, Blue = inside of glenoid fossa, Green = glenoid process that helps lock the lower jaw in place.
This captive mandible is a dead give-away when you see it, but it does mean that when it’s missing it can be confusing.
A mature adult European Badger like this (as indicated by the well-developed sagittal crest) would also normally have extremely extensive wear on their molar teeth, due to the abrasive grit in the gut of their main diet of Earthworms.
Extensively worn upper molars of an adult European Badger
But the mystery specimen has remarkably little wear on those massive molars. This suggests that it probably had a different diet than is usual for a Badger from northern Europe – and no, not mashed potatoes. The same species in southern Europe has a different diet to their northern counterparts, dominated by insects and fruit, so I wonder if the specimen was collected during someone’s holiday to somewhere in the Mediterranean?
[UPDATE 28th April 2020. Several people have kindly shared images of their badger specimens and it seems that the level of wear in my specimen is not as common as I thought. In one discussion the issue of soil type was raised and I think that may play a big factor. This specimen came from Devon, in an area with sandy soil. Other specimens from areas with muddy or silty soils showed much less wear. This may be coincidence, but it would make sense that Earthworms with coarser soil in their gut would be more abrasive to eat and therefore cause more dental wear. That would be fairly straightforward to test using museum collections. If this hypothesis about wear is correct, then the mystery specimen could be from anywhere with soils that aren’t too sandy.]
I hope you found that useful, or at least a bit of a distraction from lockdown. Stay safe!