If you can remember that far back, you may remember that fish parasite was a member of the Copepoda, which is a group within the Crustacea. Most (although not all) copepods that parasitise fish are members of the Siphonostomatoidae and this week’s mystery object is part of that same Order.
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 I gave you this taxidermy specimen from the Dead Zoo to have a go at identifying:
It turned out to be easier than I suspected, because an image of this specimen just so happens to be used on the Wikipedia page for the species. This was a bit of a give-away for anyone who even got close to the type of animal this is. So let’s figure out what general type of animal we are dealing with.
First of all, it’s fairly clearly a rodent when you look at those incisors. I suppose incisors like that could be found in one of the lagomorphs (rabbits, hares and pikas) but they all have much larger ears in relation to their bodies (even the relatively shorter eared pikas have much bigger ears than the mystery specimen).
There are a lot of rodents, but this one is quite large, which helps narrow things down. The majority of large rodents are either semiaquatic (like Capybara, Beaver and Coypu – and it’s not one of them) or spiky (a variety of unrelated porcupines from the Old and New Worlds). Then there are the maras, agoutis, and pacas (plus relatives), but they all tend to have almost absent tails and quite long legs compared to the mystery object.
There is another group that has some moderately large members though – the hutias. There are 10 species living on various Caribbean Islands, with a relatively wide variety of adaptations thanks to island effects. In particular their tails vary from being almost absent to being quite long, thick and prehensile. Checking tails should pretty much seal the identification. Of course, it’s much easier to spot when there’s a photo of the same specimen, on it’s quite distinctive base, with a label:
So well done to everyone who figured this out that this is the Bahamian Hutia Geocapromys ingrahami (J.A. Allen, 1891), especially if you didn’t spot the Wikipedia entry!
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 😉