Friday mystery object #393 answer

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

It was a bit mean of me to not include a scale, but several of you managed to work it out regardless.

The overall group is fairly easy to spot, since it has 10 legs, the front pair bearing claws (or chela if you want to get technical) and the main body area is rounded. So it’s a crab.

In addition, the long legs and small body give it an overall shape reminiscent of a spider, so it’s a good bet that it’s some kind of spider crab.

Now, there are quite a lot of types of spider crab out there, but that sub-triangular body shape and those long legs help narrow down the possibilities further. In fact, it does share some similarities to the gigantic Japanese Spider Crab.

Japanese Spider Crab specimen at American Museum of Natural History. Image from Popular Science Monthly, June 1920

Unlike the Japanese Spider Crab (which was suggested), this doesn’t have extremely elongated chela. So not one of them. It’s also way too small, although my lack of a scale bar doesn’t make that obvious – sorry! However, the mystery object is in the same family (the Inachidae).

Once you start looking at the genera in the Inachidae there’s only one that matches the mystery object’s proportions, and that’s the Macropodia. Once you get that far, it becomes a case of discounting possibilities based on much more detailed features.

The Marine Species Identification Portal is a fantastic resource for checking this finer level identification. Going through the various species descriptions in there helps spot the key features for distinction between species.

In this case, the mystery object is particularly similar to M. tenuirostris and M. rostrata and it’s mainly the shape of the carapace around the ‘shoulders’ where the chela attach to the body that help confirm this to be the Long-legged Spider Crab Macropodia rostrata (Linnaeus, 1761).

So it was a good effort for everyone who managed to get this to family level, I congratulate those who worked this out to the genus and I doff my hat to anyone who managed to identify it to species. So jennifermacaire, my hat is doffed!

Friday mystery object #390

This week I have a mystery object that my boss, mentor and the Keeper of the Dead Zoo, Nigel Monaghan, found while working on a collection of cave bones:

Now Nigel has already worked out what it is thanks to a website that has images of skulls with id tips that you may have seen before (yep, this one), but do you recognise what this is?

I think this is a nice straightforward object, so maybe a good one for some fun cryptic or otherwise entertaining answers? Have fun!

Friday mystery object #389 answer

Last week I have this mystery object from the Dead Zoo:

I made it a bit harder than necessary by not including a scale, but then that’s part of the fun – and I think a scale might have made it all a bit too easy.

There were a lot of suggestions about what it might be, mostly referencing some kind of seat / saddle or a patella. It’s probably just about big enough to sit on, although I’m not sure it would be comfortable.

But quite a few of you did figure out what bone it is and more or less what kind of animal. It’s the manubrium (part of the sternum) of a young Humpback Whale Megaptera novaeangliae Borowski, 1781.

Here’s the specimen with our Conservator Silvia for scale next to the manubrium (it’s a little hidden by the bar supporting the mandible here). Silvia’s been busy cleaning the whale, ready for it to be dismantled in the next few weeks.

All the activity around this whale work has been keeping me busy, so I apologise for tardy replies to questions and slightly sparse answers. If you want to see what we’ve been up to, check out the #DeadZooDiary!

Friday mystery object #388 answer

Last week I gave you a bit of a mean mystery object to have a go at identifying:

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I’m not surprised that very few people worked out what it is, since there’s not much to go by, and what there is, may be a little misleading.

This scrubby-looking piece of hairy skin is not from a battle-scarred Tasmanian Devil, nor is it from a rough patch on a Badger or member of the pig family and it most certainly is not from an ape of any description.

This is, in fact, from a Walrus Odobenus rosmarus (Linnaeus, 1758). This Walrus from the Dead Zoo in fact:

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People don’t think of walruses as being particularly hairy – and this one is quite definitely bald on top (I’m familiar with that feeling…). However, last week we moved this specimen and when we flipped it on its side to squeeze between some cases, we discovered a rather hairy belly (again, I know the feeling…)

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Walrus hair tends to get less dense as the animals age (insert gag here). After a century or so on open display, with members of the public who most definitely have not read the “DO NOT TOUCH” signs, and with technicians with buckets of creosote, that natural balding had a helping hand – up top.

Underneath, the hair was left untouched and in places it’s quite dense. I’m not sure if this is entirely due to people not being able to touch the specimen, or if Walrus belly hair is more dense and plentiful than on the rest of the body, to help insulate them when sitting on ice floes.

Either way, it was fascinating to be able to see a hidden part of this specimen – a nice reward for all the effort of moving it. If you want to see more of this kind of thing, check out the #DeadZooDiary!

Friday mystery object #384 answer

Last week I gave you this unusual looking skull to have a go at identifying:

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That low and elongated shape, combined with the large number of teeth and absence of a zygomatic arch – all within the context of the relatively large (but still quite small) size – all combine to narrow this down to just a few possible options.

There are a bunch of critters in what used to be called the “Insectivora“, back in the dim and distant days of my undergraduate studies. This wastebasket for things that look like they should be chasing acorns in a cartoon was rightly broken up into more meaningful cladistic groups during the great molecular taxonomic revolution in the dying days of the last century.

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Scrat, a fictional sabre-toothed squirrel that looks like every third member of the old ‘Insectivora’

To be fair, there’s a reason why the “Insectivora” lasted as long as it did and why it took molecular research to finally tease the various groups apart. They don’t have many strong distinguishing anatomical features that are seperate them into clear higher level groupings. Sure, they look a bit different at the family level, but any higher than that and they smoosh into bunch of small toothy critters, many with no cheekbones to speak of.

However, some do have a zygomatic arch, such as the talpid moles and desmans, so it’s not one of them:

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Skull of European mole Talpa europaea Linnaeus, 1758

It also lacks the large orbits of something like a Sengi or Elephant Shrew:

Skull of a North African Sengi Elephantulus rozeti (Duvernoy, 1833).

It also lacks the well-developed sagittal and nuchal crest you’d associate with the Malagasy tenrecs:

Skull of a Tail-less Tenrec Tenrec ecaudatus Lacépède, 1799.

It also lacks the backwards projecting nuchal crest of a solenodon and it’s just too big for one of the true shrews – the largest of which is the Asian House Shrew with a skull length of around 38mm.

So this specimen isn’t as hard to recognise as it could be. The very flat top to the skull with the nostrils up high is a bit of a clue – something often (although not always) associated with aquatic animals. On closer inspection there are two likely suspects – the Web-footed Tenrec or one of the Otter Shrews (which are neither otters nor shrews).

The area around the occipital is a dead give-away here. The Malagasy Web-footed Tenrec Limnogale mergulus (Major, 1896) has an occipital region that’s hard to see in a side view, because the parietals extend down quite low, whereas the Otter Shrews have much higher parietal margin that exposes the occipital region – just like we see in the mystery object.

Finally, the size is give-away. As many of you recognised and hinted at (occasionally with some dodgy puns – I’m looking at you Tony), this is a Giant Otter Shrew Potomogale velox (Du Chaillu, 1860). These semiaquatic relatives of the tenrecs are unusual in how they swim, lacking webbed feet and relying on a laterally flattened tail to swim using a fish-like undulation. So well done to Jane, Tony Irwin, katedmonson, Allen Hazen, Rémi and everyone else who managed to work out this weird mystery.

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.

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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).

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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 #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.