Friday mystery object #379 answer

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

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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 #378 answer

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

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It was a bit of a tricky one, since the specimen has been sectioned down the midline and the bone of the maxilla has been removed to show the roots of the teeth.

However, many of you were stuck at home and had a chance to get into detail in the comments. There were some fantastic answers where the features were discussed, so I think it’s well worth sharing some of them:

Rémi said:

We are confined at home, so we searched together with my 5 years old daughter. Here are our thoughts :
– foramen magnum in a downward position, low-crown teeth, bony part behind orbite, orbites facing toward the front, so we are dealing with a primate
– but a special primate because the orbites are open to the temporal fossa. And also it has a long snout with the orbites below the nasal bone. The orbites are not big enough for a nocturnal monkey. And also the very special lower incisors in horizontal position, also know as teeth-comb. We think it is a lemur-like animal.
The brain case is not round enough for a Lorisidae. We could not find pictures of all the lemur and sportive lemur species. But we saw the picture of a skull of the cat-ish one and it fits very well.

Then

steveryder said:

Second thoughts: we cannot quite see this but in my own notes on lemur;
Canine often incisiform and procumbent, arranged laterally with incisors in toothcomb, creating array of 3.
Ist mandibular premolar often caniniform

This would then be 3 premolar, 3 molar and therefore not Varecia but more probably Eulemur….

and…

katedmonson said:

While some lemurs don’t have upper incisors, this one has small peg-like ones. A Ruffed lemur (Varecia variegate), while having the same dentition, has more of an orbital thickness.
Since the skull has been dremeled out, I am not sure how much of a diastema was between the canine and upper premolars. If there was one there, I will vote for a Ring tailed lemur (Lemur catta), female, because of the smoother occipital and more slender lower mandible. The size fits as well.

These comments all highlight features of the skull that belong to lemurs, but there is a little confusion caused by the bone removed from around the teeth.

Ring-tailed Lemur was the most popular answer, but the diastema (or gap) between the upper canine tooth and the first upper premolar that katedmonson mentioned would not be present on this specimen, even if the bone was still there. Also, that lower first premolar has a fairly simple conical/triangular shape with just one cusp – which makes it caniniform, as mentioned by steveryder.

Rather than the Ring-tailed Lemur, this is the skull of a Ruffed Lemur Varecia variegata Kerr, 1792. I think it’s probably from a female or young animal (or both) as it’s more gracile than some other specimens I’ve seen. This accounts for the reduced orbital thickness, slender mandible and smoother occipital mentioned by katedmonson.

Black and white ruffed lemur by Charles J Sharpe, 2018

Black and white ruffed lemur by Charles J Sharpe, 2018

I should say, on Twitter Michael English and Gabriella Κογντογριδη also recognised this as a Ruffed Lemur. Worth mentioning that if you use Twitter and you like identifying skulls (well OBVIOUSLY you like skulls if you’re reading this) then it’s well worth checking out the #GuessTheSkull hashtag started by Yara Haridy.

A new mystery object next week – stay safe and healthy!

Friday mystery object #378

This week I’ve gone for a slightly more artsy image for the mystery object than usual:

You can click on the pictures to get a large version, which you might find useful.

I foolishly forgot to measure the specimen or include a scale bar, so I’ll update with a length as soon as I get back to the specimen. Sometimes it’s nice to rely just on morphology, so let’s see if anyone can work out what this is before I provide more information. [UPDATE: it’s 84mm long]

Have fun!

Friday mystery object #377 answer

Last week I gave you this unidentified skull from Dublin’s Dead Zoo to have a go at identifying:

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It didn’t prove too difficult to narrow it down, with everyone recognising it as a mustelid and Rémi immediately recognising it as being one of the Martens. But salliereynolds and Chris managed to get it down to the species, which is a bit of work.

There are around seven living species in the Genus Martes, although the total number varies depending on the sources you read. They have very similar skull shapes, the same dental formula and very similar tooth shape. In my experience the main feature to differentiate them lies in the auditory bullae.

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There are some decent online resources with images of Marten skulls, so it is possible to get a handle on some options. Each bulla is a 3 dimensional structure that is inflated in subtly different ways that are really hard to describe.

In a previous post I had a similar specimen (the same species as it happens) as a mystery object and I compared some bullae, but alas the image I referred to has since been removed. However, the important point is that there’s only one of the Martens that seems to have an outermost lobe that has a well-defined anterior sulcus (a fissure towards the front edge). This feature makes me think that this is a European Pine Marten Martes martes Linnaeus, 1758.

Thanks for your help in working it out!