Friday mystery object #340 answer

Last week I gave you this mandible from the collections of the brilliant Trinity College Zoological Museum to try your hand at identifying:

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It’s quite a distinctive jaw, so I wasn’t too surprised that many of you recognised it, but I was hoping the relatively small size might have caused a little confusion – after all, it’s from a juvenile.

The robust bone and undifferentiated teeth scream “marine mammal” and the scarcity of those large teeth and that long and well-fused mandibular symphysis (the bit at the front where the two halves of the mandible meet) mean that we’re dealing with something that has an unusual approach to eating.

As Wouter van Gestel, Richard Lawrence, Rémi and palfreyman1414 spotted, it’s the mandible of that infamous oyster (and clam) devourer, the Walrus Odobenus rosmarus (Linnaeus, 1758). I’ve talked about these huge pinnipeds on the blog before (many moons ago now) but since then we’ve learned more about how they feed.

One of the most interesting elements of their feeding, apart from the use of suction to remove the soft parts of molluscs from their shells, is the use of their front flippers to create a vortex in the water that keeps the sediment that gets disturbed by their snuffling hunt through the mud from impairing their ability to see. Useful if you want to avoid predators like Orcas.

You can get an idea of what this looks like in this video:

Friday mystery object #340

This week I have a mystery object for you from one of Dublin’s hidden gems, the Trinity College Zoological Museum:

It caught my eye when I was studying some of their Blaschka models for a project I’m involved in and I thought you might like to have a go at working out what this jaw might be from.

Have fun!

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 #339

This week I have a mystery skull for you to have a go at identifying:

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I’ve made it a bit more tricky by only providing one view, but I think it should be identifiable from this.

By the way, I hope you like the NatSCA scale bar – the most useful swag I’ve ever received in a conference pack. Hoping to get another one at the Caring for Natural Science Collections one-day conference in October – really looking forward to geeking out about conservation of natural history collections!

Enjoy the 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