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!

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:

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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.