Friday mystery object #380 answer

Last week I gave you this specimen from the “Unidentified” drawer in the collections of the Dead Zoo to try identifying:

mystery380

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

Badger skull with mandible locked in place.

Glenoid

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.

Molars

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!

Friday mystery object #379 answer

Last week I gave you this rather nice, but somewhat tricky mystery object to have a go at identifying:

mystery379

As well as here on Zygoma, people were checking this out on Twitter, where it was shared under the #GuessTheSkull hashtag started by @Yara_Haridy. I strongly recommend checking it out if you’re on Twitter and also giving Yara a follow as she does some great stuff.

As to this specimen, despite the difficulty, several of you managed to work it out down to species level – which I think deserves a round of applause, because this critter is not very well-known and there are few resources out there with examples of their skulls.

So, working through the options, despite having a whiff of possum about it, it can’t be a marsupial because it doesn’t have holes in the roof of the mouth (aka palatal vacuities), a shelf on the inside of the mandible or a tearduct on the outside of the orbit (aka external lacrimal duct) – all of which are marsupial traits as illustrated on this Tasmanian Devil skull below.

MarsupialFeatures

The teeth are those of a carnivore (or perhaps I should say Carnivore) and the auditory bulla is single chambered, so it’s one of the caniform carnivores, rather than one of the feliforms (that long snout suggests the same). This rules out the cats, hyaenas, mongooses and the weird Malagasy carnivores like the Fossa.

From that point on it gets more difficult. Some people thought it was a bit foxy, but the lack of a well-defined post orbital process rules out any of the dogs and it’s clearly not a bear, seal or sealion. That leaves the members of the Superfamily Musteloidea, which includes mustelids, racoons, the Red Panda, and the skunks.

Quite a lot of people got busy searching through possibilities in the largest of those groups – the mustelids. However, most of this family have fairly short, broad skulls. Only the ferret badger skulls come close to this specimen and even they aren’t as narrow. Similarly, the raccoons and Red Panda’s have fairly broad and short skulls.

So that leaves the skunks and relatives in the family Mephitidae. That makes life much easier, since there are only four genera in the family and three of those have wider skulls than this. So that leaves one genus that only contains two species – Mydaus or the Stink Badgers.

That’s where it gets really hard. A few folks on Twitter and Allen Hazen on the blog comments managed to get it to genus (Allen also worked out that it’s female), but I was especially impressed by the efforts of Rémi and katedmonson who went that step further and managed to get the identification to species. Here are the features:

katedmonson said:

…Comparing the two, M.j. has the slender snout, and a larger infraorbital foramen than the M.m. The big decider for me was the tympanic bulla. They seem to match the M.j. but not the smoother M.m. Also, females in the M.j. are known to lack a sagittal crest, so my best guess is female M. javanensis. About 4 years old. That had just eaten 6 earthworms and two beetles. And she had a limp on her left hind limb. (just kidding about the 6 earthworms, it was only 3)

I’m not sure about the earthworms, beetles or limp and I personally think the age would be a little younger – maybe 2.5 to 3 years since the earthworms have a large amount of grit in their gut and that significantly increases dental wear in animals that eat them. However, I think the rest is spot on – this is indeed the skull of a female Sunda Stink Badger Mydaus javanensis (Desmarest, 1820).

Mydaus javanensis

Mydaus javanensis specimen at Museum of Natural History in Vienna. By U.Name.Me, 2018

These odd looking animals have habits similar to the European Badger, foraging on the ground and in the surface of the soil for invertebrates and small prey, and sleeping in burrows during the day. However, while Badgers can be a bit whiffy, these guys have a full-on skunk-like noxious spray from their anal glands.

I hope you enjoyed that challenge, there will be another next Friday and if you want some extra mystery skulls, don’t forget to check out #GuessTheSkull onTwitter.

Have a great Easter!

Friday mystery object #376 answer

Last week I gave you this guest mystery object from the Museum of Life Sciences at King’s College London:I thought it would prove tricky, as the specimen is from a juvenile animal, which always complicates things.

However, it didn’t take long for you to work out what it was and, if I’m honest, you beat me to it, so well done on that and thanks for your contributions!

Clearly it’s a carnivore as it has well-developed carnassial teeth. However, immature animals with a mix of deciduous and permanent teeth can be confusing. It also doesn’t help when the skull shape is still forming.Fortunately, to help narrow it down there is the auditory bulla and that molar tooth just behind the carnassial. The shape of these features suggest that it’s a mustelid.

There was some discussion about badgers and otters, but Bob Church settled it by providing a very useful reference containing this image:

Figure from Long, Charles A. 1965 Comparison of Juvenile Skulls of the Mustelid Genera Taxidea and Meles, with Comments on the Subfamily Taxidiinae Pocock. American Midland Naturalist 74(1)225-232.

As you can see, this is an excellent match for the mystery specimen, both in dental morphology, auditory bulla shape and even scale, allowing us to make a confident identification of juvenile American Badger Taxidea taxus (Schreber, 1777).

So well done to Jeanie, katedmondson, Bob Church and Rémi, and my thanks to you all for your help in identifying this tricky specimen.

Friday mystery object #375 answer

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

wp-1581017326202.jpg

I wasn’t sure how difficult this would be – I know carnivore skulls can be a bit of a challenge, but this is a critter that’s come up as a mystery object a couple of times before. As such, I did expect a few of the regulars to recognise this, but it proved more difficult than I thought.

That said, nobody got it. Well, somebody got it, but that person was nobody with the simple statement:

I’m guessing coati 🤔

Of course, there’s more than one kind of coati, in fact there are four: the Ring-tailed, the White-nosed (or Coatimundi), the Eastern mountain and the Western mountain.

The mountain coatis are in the Genus Nasuella and they have a very narrow and gracile rostrum (that’s the muzzle area) – so this is not one of them. The other two are in the Genus Nasua and they are recognisable by their upward tilted nasal area and their upper canines which are very tusk-like – projecting forward and triangular. The mature adults of both species have a big sagittal crest, which this lacks, but that’s probably because it’s not a mature adult.

Differentiating between the two species can be tricky, but the region around the auditory bullae can be useful in this. The Animal Diversity Web has some very useful images that can help.

The slightly more inflated auditory bullae and the angle of the mastoid process (where the muscles that control the movements of the outer part of the ear attach to the skull) tells me that this is most likely to be the White-nosed coati Nasua narica (Linnaeus, 1766).

I hope that helps in case you need to identify another of these any time soon.

Friday mystery object #374 answer

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

wp-1579810719531.jpg

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

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

label

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

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

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

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

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

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

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

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

 

Friday mystery object #373 answer

Last week I gave you this pretty cool skull to have a go at identifying:

 

wp-1578601588779.jpgmystery373

As everyone recognised, it’s the skull of a snake. I think that’s clear from those extremely long quadrate bones (highlighted in purple in the top view), with which the lower jaw articulates to allow a huge gape for swallowing prey whole. However, there are a lot of snakes out there – around 3,600 species, which means there are lots of possibilities for the species that this particular skull belongs to.

The side view allows us to rule out quite a few possibilities, since it’s clear from the teeth that this isn’t one of the front-fanged snakes (vipers and elapids).

PICT0082

Rattlesnake skull, with its big front fangs.

The light construction of the skull suggests it’s not one of the constricting snakes, which have much more robust skulls for dealing with the forces generated by the struggles of relatively large prey.

PICT0159

Python skull, with a robust construction for wrangling prey.

The teeth are quite small and although there are a couple of slightly longer ones in the tooth row, they hardly count as real fangs at a paltry 3mm long. So we’re probably dealing with one of the ‘non-venomous’ colubrid snakes (many of these are actually venomous, but lack the appropriate tools to deliver that venom through human skin).

Of course, there are still well over a thousand possible species in the Colubridae – but this is where you have to start ruling out possibilities by comparing the specimen against species that are common and widespread, to begin the process of narrowing down the options.

Since this specimen is in the Museum in Ireland, Europe is a good place to start looking for likely candidates (Ireland itself being famously devoid of native snakes). There is a rather old (published in 1913), but still very useful reference called The Snakes of Europe, by G. A. Boulenger which has a section on identifying species based on their skulls.

i_058

Fig. 6Skull of Tropidonotus natrix. (From British Museum Catalogue of Snakes). Illustration from The Snakes of Europe, by G. A. Boulenger, 1913

If you take a look through, it quickly becomes apparent that there is one species that matches the mystery object very closely – even to the position of the slightly larger teeth. It’s a species that has an interesting defense mechanism that jennifermacaire referred to:

…The closest skull I could find is from a snake that likes to roll over and play dead…

This is a fascinating behaviour seen in several snake species, but Jennifer is correct that it is seen in the species that this skull is from – the European Grass snake Natrix sp.

Of course, the story then gets more complicated again, since a couple of subspecies of Grass snake have been elevated to species in the last few years. The Iberian subspecies Natrix natrix astreptophora was recognised as N. astreptophora in 2016 and the subspecies N. n. helvetica found west of the Rhine (including in the UK) was updated to N. helvetica in 2017.

These studies were based on genetics and I’ve yet to see any way of differentiating between these species using skeletal features, so for now the best I can say about this specimen is that it’s Natrix sp. I hope you enjoyed that little slither into the world of snakes, which seems to have opened a bit of a can of worms…

 

 

Friday mystery object #372 answer

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

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

wp-1577394909957.jpg

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

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

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

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

Chrysochroa rajah from southern China. Photo by Hectonichus 2010

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

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