Friday mystery object #342 answer

Last week I gave you this flouncy fish to try your hand at identifying:

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It proved a tricky one, because it seems that based on genetic data it may be a species that has undergone convergent evolution with another type of fish to produce something very similar morphologically, but not actually closely related.

The similar fish would be the Sea Robins in the family Triglidae, as several of you opted for, but Wouter van Gestel and Rémi were a little more accurate in their cryptic suggestions of Flying Gurnard Dactylopterus volitans (Linnaeus, 1758).

These fish don’t really fly and only a few sources suggest that they can get any kind of glide going. Mostly they stick near the ocean bottom in shallow waters, using those oddly leg-like front fins to manage their more pedestrian movement and using the wing-like large fins to ‘fly’ underwater.

This particular specimen has lost its colour, thanks to the process of being preserved in alcohol, but when they’re alive they’re very colourful, with electric-blue spots on the fins. Perhaps more interestingly, this specimen was collected by Sir Frances Leopold McClintock, who achieved renown for his polar exploration and who was stationed in the Royal Navy’s North America and West Indies station as Commander-in-chief between 1879 and 1884. Since this specimen is from Jamaica, it seems likely that it collected in that period.

More mysteries next week!

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 #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!