Friday mystery object #343 answer

Last week I gave you this mystery skull from the Ulster Museum to have a go at identifying:

If you’re a regular follower of Zygoma then you may have seen some of my previous posts talking about the skulls of the various smallish carnivores like mongooses, mustelids and viverrids. Generally though, mongooses have a more domed region above the eyes, while mustelids have a shorter snout, so this is most likely one of the viverrids.

It’s a difficult one to get down to species, since it’s from a group of carnivores that have have a fairly uniform skull shape, so it takes some detailed investigation to work out exactly what we’re dealing with. However, as I have talked about before (and as palfreyman1414 remembered), there’s a very helpful identification guide developed by some French researchers which summarises some of the most useful characters to use in identification.

Most useful to my mind is the matrix of characters that allows you to narrow down the possibilities until you’re left with the most likely species (watch out, the security certificate has expired). Once you’re down to a few possibilities based on those specific characters it can help to check the specimen images on the Animal Diversity Web which lets you get a better idea of overall shape and things like tooth form.

As it turns out, my 270th mystery object also provided a useful image for comparison:

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The reduced upper second molar (or M2) and the shape of the M1 in this specimen from the Grant Museum of Zoology is remarkably similar to the Ulster Museum specimen and it turns out it’s also from a species that made it to my shortlist using the matrix. So I’m fairly sure that this is an Abyssinian Genet Genetta abyssinica (Rüppell, 1836).

To give you an idea of what they look like, here’s a Common Genet in Wrocław Zoo by Guérin Nicolas, 2008

Well done to everyone who worked out we were dealing with a genet, but particular props to palfreyman1414 who was spot on when he said:

I’m wondering if, … this is related to the Abyssinian thingy you spent hours checking on from a complicated table of characteristics across 27 species…

Well remembered palfreyman1414, well remembered…

Friday mystery object #341 answer

Last week I gave you this striking specimen to try your hand at identifying:

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It’s the skeleton of a species that I’ve spoken about before and one for which I have a bit of a soft spot.

Several of you thought it was some kind of galliform (the group of birds including pheasants, quail, chickens, etc.), but although the size and general appearance of the bill is about right, it’s not one of them.

A few of you did however know what it was. Wouter van Gestel was first to recognise this as a Hoatzin Opisthocomus hoazin (Müller, 1776), with James Bryant and Cindilla Trent dropping some nice clues to show they were also in the know.

As it turns out, the original name for the Hoatzin was Phasianus hoazin because it looked so much like one of the Galliformes – and not just in the skeleton:

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As you can see, these birds are quite striking, with colours and a crest that wouldn’t be out of place on a pheasant, but a lot of genetic and morphological research suggests that the Hoatzin is in a unique group, which diverged from the rest of the modern birds 64 million years ago, just after the non-avian dinosaurs went extinct.

Personally I think they are fascinating, with their clawed young that scramble around in dense vegetation, their limited ability to fly as adults and their unusual (for a bird) folivorous diet (that’s leaves) with associated bacterial fermentation tank crop. In fact, if any animal was on the road to becoming fire-breathing I think the Hoatzin may be it, with its ready access to methane and hydrogen sulphide belches – in fact I wonder if some spontaneous Hoatzin combustion due to these gasses gave rise to the myth of the Phoenix?

Friday mystery object #339 answer

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

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I was deliberately mean and only provided a lateral view, since I reckoned that many of you would be able to work out what it was from that.

I was not disappointed, although it definitely made things a bit more difficult.

The bill shape is fairly long and fairly thin, which is often characteristic of birds that feed in water or wet mud, but there a lot of birds which do that.  This one is somewhere between a mud-probing and worm-catching wader like a Redshank and one of the stabby-faced-fish-catchers, like an Egret.  However, there are a couple of things that make the skull different to things like either of these – unlike the herons it has an inferior angular process (that bit that sticks down at the bottom of the mandible near the articulation with the cranium). A lot of birds don’t have this, although many of the charadriiforms (waders like the Redshank) do, although theirs is a different shape – tending to be broader, rounder and generally less well-defined.

This combined with the size (around 75mm) and the bump in the upper part of the bill near the junction with the cranium leads us towards a more secretive bird that does a bit of stabby-faced-fish-catching and a bit of worm-catching. As ably hinted at by Richard Lawrence, Wouter van Gestel, salliereynolds and joe vans, this is in fact the skull of a Water Rail Rallus aquaticus Linnaeus, 1758.

These odd birds are omnivorous and well-adapted for skulking through reed-beds, with a narrow profile and high-stepping gait. As with most birds of dense habitats, they have a loud and distinctive call referred to as ‘sharming’, which they will do while they are feeding – which may contribute to their vulnerability to introduced Mink, which follow their sound and ambush the birds while they’re preoccupied with feeding themselves.

Tune in next week for another mystery object!

Friday mystery object #338 answer

Last week I gave you this mystery object to have a go at identifying:

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I thought it would prove tricky and I wasn’t wrong. For starters, it’s not a great photo – you can’t see many of the more distinctive features that might provide a clue, like the face with the nose shape. This wasn’t because I was trying to hide anything, it was simply because things have been very busy recently and I took this photo in a hurry as a record of a new specimen, rather than as an image for the Friday mystery object.

However, there are some clues available. First of all, the wing claw is on a short digit, unlike the long finger that you see in the fruitbats – plus it doesn’t have the big eyes that the fruitbats have so this is one of the microbats. Next, the scale shows that this animal would have a body length around 10cm – which is pretty big for one of the microbats.

Then you don’t have a big visible nose structure, which considering the angle of the photo doesn’t mean there isn’t one, but if it has one it’s not very prominent. In fact, there may be something a bit misleading in that area – a shiny black bump in the nose area that almost looks like a fake nose has been stuck on. This in fact is a bit if a clue as to the identify of this bat.

It’s actually a waxy secretion from just behind the nose that the males of this species produce as a signal to females and, I can attest, it’s quite pungent smelling. This combined with the colour of the fur suggests that this is a Diadem Round-leaf Bat Hipposideros diadema (É. Geoffroy, 1813).

20180913_170608-01.jpegThis is a very widespread species with a range from South East Asia to the top of Australia. Because they’re quite large and heavy they’re not very manoeuvrable, so they ambush their prey of large moths and beetles from a perch, launching themselves at anything their sonar picks up as it flies by. In fact these bats are big enough to take small birds and those large canines combined with having a very high bite force mean the Diadem Round-leaf Bat is able to handle these bigger prey and for researchers it’s reported to have a very painful bite.

This particular specimen was presented to the Museum by Customs, who seized it in the post because it lacked the appropriate import paperwork. I’m now in a bit of a quandary about what to do with the waxy secretion on the head. It has gummed down the leaf on the nose and it smells pretty strongly, so it make the specimen less useful for display, but it is still an interesting feature of the biology. It may a case of removing a sample and keeping it in a small tube with the specimen and then cleaning the rest off, so the full beauty of this bat’s face can be revealed.

 

Friday mystery object #337 answer

Last week I gave you this largely amorphous blob to have a go at identifying:

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Perhaps unsurprisingly it proved quite tricky, with most people opting for a brain, heart or gland of some kind. However, believe it or not, this is actually a whole animal.

In the comments a close suggestion came from palfreyman1414 who said:

“…invasive crab lip parasitical crustacean isolated…”

Tony Irwin clearly knew the actual answer with a nicely crafted cryptic link to the two common sequential hosts of this animal, the Flounder and the Cod. Meanwhile, on Twitter there were another couple of suggestions – one was a good general biological principle:

The other was a straight-up correct answer from Dr Ross Piper, an old zoological buddy from postgrad days and an aficionado of odd animals:

This is indeed a Codworm or Lernaeocera branchialis (Linnaeus, 1767) a type of copepod parasite that has a life history in which they spend part of their mobile larval stage parasitising flounders (and similar fish that sit around a lot) until they’re able to mate, at which point the fertilised female seeks out one of the mobile gadoid fish (the Cod family), where she gets into the gills and plumbs herself in to the Cod’s blood supply right at the heart, with her egg sacs at the gills and protected by the operculum (gill covers). She then spends the rest of her life sustained by fish blood, releasing eggs into the water and looking like a black pudding being eaten by maggots. Now those are life goals.

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Adult female Codworm in Whiting gills. Image by Hans Hillewaert, 2006

Friday mystery object #336 answer

Last week I gave you this impressive beetle to try your hand at identifying:

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Now although it’s big and showy, beetles can be hard to identify because there are just so many of them and closely related species can be very hard to tell apart.

This one has distinctive elongated jaws that mark it as being one of the stag beetles (family Lucanidae), which narrows it down, although there are well over a thousand species in the family. This one is a little bigger than most and the jaws are relatively unbranched, with a cleft at the end of a relatively squared-off and downward deflected ‘antler’.

Those ‘antlers’ are used by the males to wrestle for access to females, who have much more sensibly sized jaws and are smaller. Effectively they’re doing the same thing as deer and this is a good example of how evolution can lead to similar trends in behaviour and even sexual dimorphism across very different animal groups.

I think this is Mesotopus tarandus Swederus, 1787 which is a species from West Africa that is becoming increasingly popular in the pet trade. It has slightly shorter ‘antlers’ than the other species (or possibly subspecies) in the same genus, M. regius.

As you probably know, I’m more familiar with vertebrate identification than insects, so I was fortunate to have my intern Esmeralda, who is a keen coleopterist helping narrow this down, although I’m pleased to congratulate jennifermacaire who was on the same track with her identification.

Another mystery next week!

Friday mystery object #334 answer

Last week I gave you this unwelcome visitor to have a go at identifying:

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It’s a type of beetle – so a member of the Coleoptera or “sheathe wing” as palfreyman1414 pointed out) – in the family Dermestidae (as Wouter van Gestel intimated) and the species is Reesa vespulae (Milliron, 1939) as Tony Irwin hinted at with his cryptic clue:

Sometimes attached to a mogg, this seems to belong to a diminutive scooter

There were several other nice cryptic suggestions in the comments section, plus some on Twitter, so very well done to everyone who worked out what this was.

The species gets the name vespulae from its affinity with wasp nests, where it feeds on dead wasps and the scraps of insects that the adult wasps feed their larvae, so they’re sometimes called the Wasp-nest dermestid.

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The natural target of Reesa vespulae

These tiny beetles can strikes terror into the heart of a museum curator, since they are well adapted to feed on dried insect remains (of which we have huge numbers making up our collections) and they are parthenogenic – meaning that they reproduce without mating (only females of the species are known) and just one individual is all it takes to create a full-blown infestation.

Damage caused by a Reesa vespulae infestation

Damage caused by a Reesa vespulae infestation

You can tell them apart from some of the other dermestid beetles (many of which are also museum pests) because they have ‘hairy’ elytra (or wingcases) with a lighter coloured patch on each of their ‘shoulders’ (they’re not shoulders, but you probably get what I mean).

If you find one of these wee beasts in your collection, be afraid – be very afraid!