Friday mystery object #537 answer

Last week I offered up a fossil specimen from the collections of the Horniman Museum & Gardens for you to have a go at identifying:

The type of preservation here is quite distinctive for those familiar with fossil Lagerstätten (sites of exceptional fossil preservation or concentration). This silvery sheen on a piece of dark slate is immediately recognisable as the type of soft-bodied preservation I expect to see in specimens from the Burgess Shale.

The Burgess Shale is an incredible fossil locality in the Canadian Rock Mountains, that preserves animals from marine ecosystem that was rapidly buried around half a billion years ago. The rapid burial and some factor that created a hostile environment (low O2 or perhaps a hypersaline seep) prevented the decay of the soft tissues of the animals that were buried and created conditions that preserved soft parts of the animals present, rather that just preserving hard parts,

This unusual set of conditions means that rather than just seeing shells of animals like brachiopods and carapaces of trilobites, we get a much more accurate snapshot of marine life at the time, including a variety of bizarre worm-like animals and creatures with forms that aren’t recognisable as being from types of animal alive today.

This particular specimen is not all that strange in comparison to some of those organisms that diversified in the Cambrian explosion (a name we use to describe the apparently sudden diversification of multicellular life around 540 million years ago).

Artistic reconstruction of the Cambrian (Drumian) Marjum biota in the House Range of Utah, USA, including radiodont components. Credit: Holly Sullivan (www.sulscientific.com) 19 January 2021.
Used in Pates S, Lerosey-Aubril R, Daley AC, Kier C, Bonino E, Ortega-Hernández J. 2021. The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian) PeerJ 9:e10509 https://doi.org/10.7717/peerj.10509

The mystery object actually doesn’t look too much different from some of the living Polychaetes, such as the pelagic Gossamer Worm:

Planktonic polychaete worm in the genus Tomopteris. Image by uwe kils, 2005

However, there are several different Polychaete worms recognised from the Burgess Shale, so it does take a bit of close investigation to work out which it’s likely to be.

Adam Yates took a good look and while his first response of Canadia spinosa Wallcott, 1911 matches the label with the specimen, he updated his answer. Looking at the setae structure, I think that Adam is right in rethinking this. In Canadia spinose the setae appear more flight-feather-like, with longer leading bristles and a more swept-back appearance:

Smithsonian specimen of Canadia spinosa. Image by Bruce Martin, 2015. Source https://collections.nmnh.si.edu/search/paleo/?ark=ark:/65665/3c7b58e5ae22a4a34b6587ec5cfc46b49

The setae of the mystery specimen appears a bit different, with bristles of a more similar length that stick out in more separated tufts. This makes me concur with Adam, in that we may be looking a Burgessochaeta setigera (Walcott, 1911):

Burgessochaeta setigera USNM198705. Image from Parry et al. (2016) The impact of fossil data on annelid phylogeny inferred from discrete morphological characters. https://royalsocietypublishing.org/view-large/figure/15125348/rspb20161378f01.jpeg

I hope you enjoyed that little journey into the distant past as much as I did. Learning about the Burgess Shale was a highlight of my undergraduate days, as it offered a glimpse at both the lost diversity of the past, and a hint at the unfathomable depth of time through which life has persisted, adapted and evolved.

Friday mystery object #536 answer

Last week I had two bony elements from the same skeleton for you to have a go at identifying:

I suspect either one would have been enough, but it’s nice to be able to share a couple of elements so they’re online and available for reference to help with future identifications.

Adam Yates offered up a great clue in answer to this particular mystery:

This puzzle gave me a heap of trouble. I eventually settled on the villainous goblin-creatures from Middle-Earth, particularly the laage species

As a huge fan of Tolkien I appreciated this reference to Orcs (although the spelling is of course different to the kind of Auks we’re looking at here). The little anagram of “aalge” was also a nice touch – as that’s the species name for this particular type of Auk – the Common Murre or Guillemot Uria aalge (Pontoppidan, 1763).

Common Murre /Guillemot. Image by Andreas Trepte, 2011

This is actually a species I’ve had on the blog about 10 years ago – although that was from a different individual and I only had the sternum that time:

Friday mystery object #286 answer

The specimen I used this time is from a more-or-less complete skeleton in the Dead Zoo’s comparative avian osteology collection:

I love this resource, as it provides a great tool for zooarchaeologists and comparative anatomists to check the identifications of found bones, or to consider the proportions and structural features relating to locomotion, behaviour or whatever else piques their interest.

These days I rarely get a chance to look through the collections, and most of my time is spent in meetings or dealing with emails or other admin, but every now an then an opportunity arises to open a couple of draws to remind myself of how I got into the museum world, and it’s always a pleasure.

More mysteries next week – assuming I get a chance to open a drawer sometime soon!

Friday mystery object #535 answer

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

This is a pretty distinctive species, but not without some very similar relatives who can complicate things.

The speckled crimson pattern on the forewings of this species provide all the clue you really need for the identification – it’s a Speckled-crimson Moth (or Crimson-speckled Flunkey, or Crimson-speckled Footman) Utetheisa pulchella (Linnaeus, 1758). I even dropped a hint when I described it as a “rather beautiful beastie” as the Latin species name pulchella translates to “beautiful”.

This species occurs across Africa, Asia, and Europe, with occasional migratory visitors turning up in the UK and Ireland – in this case in Tramoe, Co. Waterford.

However, there is a very similar looking species in the same Genus that goes by the name Utetheisa pulchelloides – which literally means “resembling Utetheisa pulchella“. The common name for that species is the Heliotrope Moth, which mainly occurs in the Southern Hemisphere – mainly New Zealand, Australia and up into Borneo and Singapore.

Here’s a comparison between specimens of these two species from other collections:

Utetheisa pulchelloides, dorsal view. Image by Caroline Harding, MAF (CC BY 3.0 au)
Utetheisa pulchella specimen from Naturhistorisches Museum Vienna, Austria, Image by Kurt Kulac 2006-05-20 (CC-BY-SA-2.5)

You can see how similar they are – and if you look at the underwing the U. pulchelloides specimen looks more similar to the mystery specimen – which I suspect may have led Adam Yates down the wrong path.

If you look at the forewing you might notice that U. pulchelloides has small black triangles along the margins, whereas U. pulchella (and the mystery specimen) has truncated triangles or rectangles. You may also notice that the crimson speckles of U. pulchelloides are more faded and have a dark margin.

So well done to Chris Jarvis, Katenockles, and Jonathan T who all spotted the subtle differences either in the comments or on Mastodon.

Friday mystery object #534 answer

Last week I gave you this genuine mystery object from the forests of Borneo to get your thoughts on:

This was sent to me by Dave Hone (who runs Archosaur Musings), but it was found and photographed by his colleagues Lauryn and Tom of Queen Mary University of London, who are doing research in Borneo.

I had an idea of what it might be, and I’m pleased to say that everyone who responded – both here and on social media – came to the same conclusion as me.

This is the left ilium crest from the pelvis of a juvenile animal. That much can be seen from the unfused sections where this would have connected to the sacral vertebrae and the pubic bone:

Photo of unfused surface of the ilium that would have connected to the pubic bone by Tom Fayle, 2026

An unusual thing about this ilium is the position of the point of fusion with the sacrum:

For most species the iliac crest (that’s the curved bit at the top) extends upward quite a bit before flaring out – and that flaring is often quite squared off and tends to be narrow and more blade-like. That configuration is what you would expect to see from most quadrupedal mammals – a notable exception is in the form of the human pelvis, due to our bipedalism.

However, this pelvis doesn’t quite conform to the human shape, as it’s a little bit less curved and a little more blade-like. This is consistent with one of our close cousins – there are some useful comparisons of disarticulated primate pelvises on the Bone Clones website and while this is very similar to a female Chimpanzee that’s shown, the location of Borneo suggests a more likely option – a Bornean Orangutan Pongo pygmaeus (Linnaeus, 1760).

On BlueSky, osteoarchaeologist Terry O’Connor spotted this straight away, as did Adam Yates and Chris Jarvis here in the comments. 10 year old Viren, who is a new visitor to Zygoma, was also spot-on. So well done to everyone, and thanks for your thoughts – it’s great to have my conclusion supported!

Friday mystery object #534

This week I have a genuine mystery for you to help solve, courtesy of Lauryn and Tom – researchers working in the forest in Borneo, and passed on by Dave Hone (an old friend and fellow blogger who runs Archosaur Musings):

Photo by Tom Fayle, 2026
Photo by Tom Fayle, 2026
Photo by Tom Fayle, 2026

I think I know what this is and what it’s from, but I’d love to hear your thoughts on this Bornean bone in the comments below!

Friday mystery object #533 answer

Last week I gave you this bird pelvis to have a go at identifying, as part of a series of posts on that particular feature across birds utilising different environments:

It probably wasn’t the easiest challenge, since this pelvis is damaged. It’s missing part of its dorsal surface and with some small amount of damage to the posterior margin of the right ischium (that’s the broad bit that flares out on the bottom left of the image) and with both of the pubic bones snapped (those are the long skinny bits that stick out to either side).

Still, the overall shape still gives some useful clues. The long, narrow, triangular form offers some ideas about the distribution of mass and use of the legs, to give a sense of possible locomotion habits.

The pelvis is very flat and the points of articulation with the femur are quite far forward:

At least in comparison with something like a Chicken:

This suggests something that has a centre of mass that’s quite far forward compared the foot position. This immediately raises the question of why? The obvious answer for me is that this is a species that doesn’t brisky strut around, relying on more of a low-speed waddle to get around – or perhaps a paddle.

Waterbirds have legs located quite far back in the body to aid propulsion in the water. Perhaps a bit confusingly this requires the articulation of the femur with the pelvis to be pushed further forward due to the more horizontal orientation of the spine to allow the correct orientation of the legs to push water backwards and the body forwards – unlike terresrial species that are more interested in pushing the body upwards against gravity.

There are of course a lot of waterbirds, from the Pelecanimorphae mentioned in the comments by Adam Yates, to the Anseriformes. That’s what we’re looking at here.

There are a lot of ducks and geese, so narrowing it down isn’t easy. The size of this mystery specimen is in the right range for a large duck or small goose, but if you look at the left ischium (the undamaged one) you’ll notice a deep notch – this is something seen in geese.

You may also notice an additional extra notch – which I think offers a great clue to hint at the species. This is the pelvis of a Brent Goose Branta bernicla Linnaeus, 1758.

I’m not sure if the thoughts I’ve laid out here, and over the last couple of mystery objects are helpful for guiding future identifications of bird pelvises, but I hope they may be of use. Let me know your tips on working these things out – more ideas are always welcome!

Friday mystery object #532 answer

Last week I gave you the second of a series of bird pelvises to try your hand at identifying:

This one proved a bit more difficult than the previous example I offered up, which was from a Chicken – here’s that one for comparison:

Chicken pelvis

As you can see, our mystery pelvis is a good bit smaller than that of the Chicken, and in terms of the shape, while it has some similarities, but it’s more compact and almost square. I’m not 100% sure why, but that makes me think of something that has a more upright body orientation than a Chicken.

Part of the reason it’s more square is that the areas of muscle attachment for the iliotrochantericus caudalis muscles (which I talked about a couple of weeks ago) don’t extend far forward, which suggests its femur isn’t being stabilised to enable a long stride. The attachment is quite wide though, so I suspect it may be optimised to cope with large forces in a burst instead.

There are a few species that would fit the bill (if you’ll excuse the pun) including Grouse – which was suggested by Chris Jarvis and it is remarkably similar – but this is the pelvis of a Rock Dove (in this case the domestic version) Columba livia Gmelin, JF, 1789 which was correctly spotted by Adam Yates.

I thought this one might be nice to use, as it lets me share a blast from the past that looks at the explosive take-off of a Pigeon, from Ben Garrod’s TV series Secrets of Bones, which I had the privilege to be scientific advisor for back in 2014. I hope you find the clip interesting!

Friday mystery object #531 answer

Last week I gave you this bony structure to identify:

I didn’t think this one would prove too difficult, since I went with something that most people have probably encountered on their dinner table or thrown in their domestic waste at some point. I wasn’t wrong and Chris Jarvis was first to drop a hint, with reference to Elvis the Pelvis and a famous brand of fried foodstuff from Kentucky.

This is of course the pelvis of a Chicken Gallus gallus domesticus (Linnaeus, 1758).

Bird pelvises are interesting structures, that are a bit more extensive than the usual mammalian equivalent1 due to the extended and fused vertebrae around the sacrum – the sacrum being the area of fused vertebrae where the hip bones attach to the spine. This extended region of fused vertebrae along the midline of the pelvis is referred to as the synsacrum.

In birds the fusion of the pelvis can be very extensive, and provide large areas for muscle attachment. If you look at the bottom of the photo above you can see where there are two scooped-looking sections, and this is where the “oysters” would be found in a roast Chicken. Those “oysters” are more technically referred to as the iliotrochantericus caudalis muscles and they attach to the femur and help stabilise the bird while walking.

The highly sculpted form of a bird’s pelvis creates quite a distinctive locomotor unit that reflects the way in which the bird uses its legs to walk, perch, paddle, swim or whatever else it may get up to. This means that the pelvis of a bird will usually reflect function very well and it will also carry a strong taxonomic signal since birds that are closely related will often share similar locomotion habits, lay similar sized eggs (that have to pass through the pelvis) and so on.

To my mind, the synsacrum provides an evolutionary mechanism to allow effective bipedalism while maintaining a horizontal spine – as opposed to the upright stance used in primates, which seems to come with some issues if my back is anything to go by. My background is in biomechanics and anatomy, so for me this is a topic that I find very interesting. So interesting that I may see if I can find another bird pelvis from a species with different habits to test your skills next week – let me know what do you think of that idea in the comments!

  1. Of course, nature being what it is, there is an exception to that generalisation with the Xenarthra, whose members have a similiarly fused synsacrum. ↩︎

Friday mystery object #530 answer

Last week I gave you this cute little netsuke (pronounced nets-keh) to see if you could identify what it was carved from:

I was hoping it might offer a bit of a challenge, with a few options being put forward for a variety of ivories, and perhaps some pondering on the topic of the carving, but I was disappointed by how quickly and comprehensively everyone told me exactly what this is.

I suppose I shouldn’t be surprised, since the community here on Zygoma are really good at identifying things (I suspect there’s a bit of self selection going on there!) The shape is quite distinctive, but more there’s also a small section on the base that’s just visible, which is very characteristic if you know what you’re looking for.

Here it is pictured from underneath:

This is an example of vegetable ivory – a material derived from the nut of a Tagua Palm in the genus Phytelephas Ruiz & Pav. These large seeds have a creamy, ivory coloured flesh that is easily carved when wet, but which become hard when dried.

This particular specimen is from the National Herbarium at the National Botanic Gardens in Glasnevin, where I was fortunate to be shown it during a visit to see a very impressive herbarium digitisation project they’ve been undertaking.

The vegetable ivory lacks the Schreger lines found in proboscidean ivories, such as mammoth or elephant:

Section through elephant ivory, clearly showing the Schreger lines – an optical effect caused by light scattering caused by dentine fibrils laid down during the growth of the tusk.

There are plenty of other ivories of course, some of which have similarly distinctive aspects to look for, like Walrus ivory that has a central section that looks almost like clouds due to secondary dentine secretion in the root space of the tusk, and Hippopotamus canine ivory that has a subtle discoloured arch in the middle that results from the flattened triangular shape of the tooth.

In the case of the Tagua nut there is a hole in the centre, but this will often be avoided by not carving too deeply, or by incorporating the natural void into the design of the carving.

So well done to everyone – your skills are still top notch! You can test them again soon, as there will be more mysteries to come next week.

Friday mystery object #530

One type of enquiry we get in the museum relates to the identification of natural materials. Often these come from law enforcement or customs officials, who may need an expert eye cast over a material to check whether it’s been imported or sold illegally.

Here’s a worked piece of natural material – I’d be keen to hear your thoughts on what it might be:

As ever, you can leave your suggestions in the comments section below. I look forward to hearing your thoughts!

Friday mystery object #529 answer

Last week I gave you this somewhat faded and oddly shaped fish to have a go at identifying as a New Year challenge:

It was a very big ask, as the image isn’t really detailed enough to allow a species identification, but it was great to hear your various thoughts.

Adam Yates got very close with the suggestion it could be one of the Loricariidae – a family containing the armoured suckermouth catfish, but while this is from the same Order (the Siluriformes) this particular catfish is from a different Family.

While it has an armoured appearance, and shares those ornamented pectoral fin spines that are found in many catfish, this one has a filamentous tail and dorsal fin (that you can only just make out). What you can’t really see are the eight pectoral fin rays and the seven barbels present on the head.

This long thin tail is a hint that this is one of the Banjo Catfish, and the details of the barbels and pectoral fin rays I mentioned above let us know that it’s the Sevenbarbed Banjo Aspredinichthys filamentosus (Valenciennes, 1840).

For some reason the name Banjo Catfish always makes me think of this scene from the film Deliverance:

Musical shenanigans aside, these South American fish are bottom feeders in brackish waters, and have the unusual reproductive trait of the female attaching her eggs to her underside, so they can be moved around in the muddy waters in order to keep them oxygenated during their development.

That was certainly a challenging mystery object to start 2026, so I may see if I can find a slightly easier, but hopefully no less interesting specimen for the next mystery object!

Friday mystery object #529

Happy New Year! I hope you enjoyed seeing in 2026 and I wish you all a very healthy and enjoyable year ahead.

This Friday’s mystery object is a specimen from the spirit collections in the Dead Zoo:

Do you know what this mystery aquatic beastie might be?

Let me know your thoughts in the comments below – I hope you enjoy the challenge!

Friday mystery object #528 answer

I hope you had an enjoyable Christmas! Last week I gave you this chonky skull as a mystery object to have a go at identifying:

It wasn’t anything particularly challenging or unusual, but it’s a very cool skull that we recently put on display in the Dead Zoo Lab in Dublin, and it’s nice to have a chance to share it here.

While Caimans did get a mention, pretty much everyone worked out that this is the skull of an Alligator – although which of the two living species it might be sparked some conversation.

In the words of Adam Yates:

Clues include snout shape and length, divided nostrils and lack of a lateral notch for receiving the big fangs from the lower jaw.

Excellent advice, although the simplest way I use to tell the difference is to check how much of a U-shape the maxilla forms. In this case it’s very U-shaped, which says American Alligator Alligator mississippiensis (Daudin, 1802).

An American Alligator by Postdlf, 2006

I’m keeping this answer brief for this mystery object, since I’m sitting at a dinner table with family after a fantastic – and very large – meal, so I’m struggling to be creative with all my blood rushing to my stomach rather than my brain.

I hope you had a great Christmas, and I look forward to sharing more mystery objects for you in 2026!