Friday mystery object #452 answer

Last week I gave you this guest mystery object from the comparative anatomy collection of the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne, courtesy of Rohan Long:

Image by Yijie Cheng, 2023

This is one of those specimens that it can take a while to get your head around, as most of the key features are entirely missing. From the top, the skull almost looks mammalian. Perhaps a little like a large rodent missing part of its zygomatic arches:

Skull of a Striped Ground Squirrel

Even from the side there are some similarities, although it looks a bit more like a turtle:

Image of mystery bones by Yijie Cheng, 2023
Image by Yijie Cheng, 2023
Skull of a Loggerhead Turtle

If you look closely at the underside of the skull, you’ll notice that it has a single occipital condyle, which is something you see in reptiles and birds, but that view of the underside also becomes clear that the front section of the mystery object doesn’t taper to create a bill, like you’d see in a turtle:

Image by Yijie Cheng, 2023

In fact, a bill is the most diagnostic feature that’s missing, and that’s because it’s fallen off.

Those cervical vertebrae are quite distinctively avian – and from a long-necked avian at that. Once you realise that this is the braincase of a fairly large long-necked bird, the next task thing is to look at birds with a bulbous and cleft region on the head, just at the base of the bill (most bird skulls taper down to the bill).

For me that indicates one species above all others – the Mute Swan Cygnus olor (Gmelin, JF, 1789).

Mute swan skulls “Cygnus olor”. Technique of bone maceration on display at the Museum of Veterinary Anatomy, FMVZ USP.

I’d like to offer a hearty ‘bravo’ to Adam Yates, who was the first to comment and correctly identify this with a great cryptic clue:

It is an anseriform for sure the large oval basipterygoid articulations are a give away. With that profile, i’d lose my voice while trying to say the name of a certain Western Australian River.

Adam YatesJanuary 20, 2023 at 8:45 am Edit

This was backed up the ever-knowledgable Wouter van Gestel who runs SkullSite, which is the single most useful online resource I know of for bird skull identifications. Speaking of useful online resources, Rohan has been working on a project to make the collections of the Harry Brookes Allen Museum of Anatomy and Pathology available online – so be sure to check it out!

Friday mystery object #451 answer

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

In the ornithological community, birds like this are sometimes referred to as an LBB / LBJ (Little Brown Bird / Job), because they are small, brown and hard to identify (especially in the field) due to the large number of similar looking species.

This specimen has a robust, conical bill and grey-streaked breast, which led some of you to think it could be a juvenile Crossbill or perhaps a female Grosbeak. However, as indicated by Wouter van Gestel in an excellent cryptic clue (and by Tim Dixon in a rather rude one), this is a Corn Bunting Emberiza calandra Linnaeus, 1758. It was collected in County Dublin and donated to the Dead Zoo in 1880.

These seed-eating passerines were widespread in arable farmland across Ireland in the 19th and early 20th centuries. However, changing land use practices reduced the available habitat until they became locally extinct as a breeding species in the late 1990s – well within living memory for many people.

The Irish name for the Corn Bunting is Gealóg bhuachair and an interesting fact about these birds is that their populations are remarkably sedentary, allowing them to develop unique dialects in their breeding area. This means that even if this species is reintroduced to Ireland – assuming farming practices become better suited to their survival – the landscape will never again ring with quite the same song that these birds would have sung in the past.

Friday mystery object #446 answer

Last week I gave you this mystery object from the collection of the late Dr Don Cotton to have a go at identifying:

It led to some really interesting discussion in the comments, which converged on this being a whale vertebra. More exactly, one of the cervical (neck) vertebrae from the neck of a smallish to medium-sized whale.

Whale necks are very short and the bones are a bit odd, as in they can be fused together in the adults and sometimes in juveniles (but not always), and depending on the species they might not fuse at all. This one is not fused, but you can see facets just above the solid centrum section, where the vertebra in front of this one would have snugly nestled.

It looks like the lateral processes (bits that stick out to the side) that would have extended from the facets, but have broken off, presumably due to the action of the waves on the shore where this specimen washed up. This makes it even harder to identify which of the cervical vertebrae this is or the species that it came from. However, the squared centrum and spur-like lower processes make me think that this is probably from one of the cervicals nearer the thoracic (chest) region – my guess would be cervical number 6 (cervical 7 often lacks the lower processes while 3,4 and 5 tend have better developed lower processes).

In the comments the discussion focussed on large dolphins, like the Beluga or Narwhal, but the shape reminds me more of the cervicals I’ve seen from baleen whales like the Fin Whale, although the size is all wrong. However, there is a much smaller member of the Balaenoptera species complex that inhabits Irish waters: the Northern Minke Whale Balaenoptera acutorostrata Lacépède, 1804 – which is what I think this mystery object probably came from.

I could be wrong and this could possibly be from a large dolphin that occurs around Ireland, like an Orca or Long-finned Pilot whale, but these have extensive fusion of the neck vertebrae, so I’m going to stick my neck out with the Northern Minke.

Northern Minke Whales are well documented in the waters around Ireland, especially during the spring and summer months. Don Cotton was a founding member of the excellent Irish Whale and Dolphin Group, which is the source of much of the information we have about the occurrance of these otherwise enigmatic animals in Irish waters.

Friday mystery object #430 answer

Last week we had a second guest mystery object from Rohan Long, who is based at the Harry Brookes Allen Museum of Anatomy and Pathology at the University of Melbourne.

Image by Gavan Mitchell, 2022

It was a genuine mystery object and it certainly proved quite tricky. There were quite a few suggestions of gibbon, but the proportions of the long bones aren’t right, with gibbon radius and ulna bones proportionally far longer in relation to the humerus or any of the the bones of the legs than what we see above. The skull does look quite gibbony gibbonesque gibbon-like, but generally gibbons have an auditory bulla (the region on the underside of the skull that houses the hearing apparatus) that strongly curves, almost like a boomerang, whereas here the feature is much straigher.

Image by Gavan Mitchell, 2022

The teeth tell us that the mystery object is from one of the Cercopithecidae (Old World Monkeys) since there are only two premolars instead of the three that you find in the Platyrrhini (New World Monkeys). That helps a bit, but there are still over 150 species in the Cercopithecidae to consider.

Some can be ruled out fairly easily, such as members of the Papionini, like baboons and macaques, which have adults that are more prognathic (their jaws jut forward) that this specimen. This is less true for juveniles (jaws jut more as the animal grows and matures), but we can ignore that here, since the mystery specimen has well-fused sutures and visible wear on the teeth, so we know it’s an adult.

Image by Gavan Mitchell, 2022

One thing that can be useful to consider when trying to identify primate skulls is the shape and position of the nasal opening. This can vary within species and it can be a feature sensitive to the angle at which a photograph is taken (making it more difficult to assess from images), but overall it can help narrow down possibilities without having to get into too much fine detail early in the identification process.

Image by Gavan Mitchell, 2022

The Mammalian Crania Picture Archive has well standardised images, including a reasonable variety of primates with males, females and animals of different ages represented. They also provide some measurements for each specimen, that may be useful when making comparisons. The primate page is here in case you’re not familiar with this very valuable resource.

Over the last week I’ve taken a look through a wide variety of skulls from different primate taxa and I’m confident that the mystery specimen is from the Colobinae. I think the position of the nasal opening (especially the top part of the opening in relation to the eyesockets) is helpful in distinguishing possible species within the subfamily. This makes sense when you consider that a third of the genera in the Colobinae are in a group known as the “odd-nosed monkeys”.

In this specimen the nasal opening forms a shield shaped hole with a flat top that starts quite high in relation to the eye sockets. In most species it starts lower, sometimes well below the line of the bottom margin of the eye socket. The Red Colobus is superficially quite similar, but when you look at other features it doesn’t look right – for example, if you look at the underside of the skull it has several different features, include a differently shaped incisor arcade and the pterygoids (the wing-shaped bits of bone that spread to either side, just behind the palate) are a different shape.

However, I did find a species which matches much better, so I am tentatively suggesting that the mystery object may be a Black-crested Sumatran Langur (AKA Mitred Leaf Monkey or Sumatran Surili) Presbytis melalophos (Raffles, 1821). If not that species I think the mystery specimen will be in the same Genus. There will undoubtedly be additional species with similar skulls that I’ve not seen, but within the limits of the resources at my disposal I don’t think I can do any better than that.

Oddly enough, I have had a skull of this species as a mystery object before, but it appears to be from a much younger individual, so at first glance it looks quite different, but the general features of the nose still remain:

My thanks to everyone for your suggestions and many thanks to Rohan for sharing this mystery object. It’s been an interesting one and has reinforced my conclusion that primate skull identification can be REALLY difficult!

Friday mystery object #429 answer

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

It turned out to be easier than I suspected, because an image of this specimen just so happens to be used on the Wikipedia page for the species. This was a bit of a give-away for anyone who even got close to the type of animal this is. So let’s figure out what general type of animal we are dealing with.

First of all, it’s fairly clearly a rodent when you look at those incisors. I suppose incisors like that could be found in one of the lagomorphs (rabbits, hares and pikas) but they all have much larger ears in relation to their bodies (even the relatively shorter eared pikas have much bigger ears than the mystery specimen).

There are a lot of rodents, but this one is quite large, which helps narrow things down. The majority of large rodents are either semiaquatic (like Capybara, Beaver and Coypu – and it’s not one of them) or spiky (a variety of unrelated porcupines from the Old and New Worlds). Then there are the maras, agoutis, and pacas (plus relatives), but they all tend to have almost absent tails and quite long legs compared to the mystery object.

There is another group that has some moderately large members though – the hutias. There are 10 species living on various Caribbean Islands, with a relatively wide variety of adaptations thanks to island effects. In particular their tails vary from being almost absent to being quite long, thick and prehensile. Checking tails should pretty much seal the identification. Of course, it’s much easier to spot when there’s a photo of the same specimen, on it’s quite distinctive base, with a label:

Image by Illustratedjc, 2015

So well done to everyone who figured this out that this is the Bahamian Hutia Geocapromys ingrahami (J.A. Allen, 1891), especially if you didn’t spot the Wikipedia entry!

Friday mystery object #423 answer

Last week I gave you this fishy looking critter to identify:

It wasn’t an overly difficult one for most of you, since it is a very distinctive and somewhat unusual animal with some immediately recognisable features. Most obvious are the gills.

Bony fish only have one visible external opening on either side of their head where water exits after it’s flowed over the gills, and this is well hidden when the gill flap (or operculum) is closed. So this is clearly not a bony fish.

Most modern sharks have 5 external visible gill slits, but this one has six. That makes it a bit of an evolutionary anachronism. There are only seven species of shark with more than 5 gills and they are all in the Order Hexanchiformes, which narrows down the possibilities considerably. Of those, two have seven gills, leaving just five possible species.

Those five species sit in just two families – the Cow Sharks and the Frilled Sharks. These can be separated based on a variety of features, but the most obvious is that the Cow Sharks have fusiform (or spindle-like) body shapes with a very pointed nose to help them move efficiently through the water by minimising drag. The Frilled Sharks have more anguilliform (eel-like) bodies with a blunter head and mouth set further forward in relation to the eyes – a feature about the mystery object picked up on by Allen Hazen.

There are only two species of Frilled Shark to choose between and I’m not sure I could tell the difference between them based on the photo provided. However, one species is only found off the coast of South Africa, and in last week’s post I dropped a (hopefully) helpful clue – this specimen was caught off the coast of Ireland.

That means this can only be the Frilled Shark Chlamydoselachus anguineus Garman, 1884. Well done to Adam Yates for being the first to get it spot on. This specimen was caught off the coast of County Donegal at a depth of 390 fathoms (or 713 metres in standard units) just over 21 years ago. A special mention to Pete Liptrot on Twitter who managed to identify this mystery object to the actual specimen – not just the species!

Friday mystery object #409 answer

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

Everyone spotted that this is the skull of a toothed whale (or large dolphin), but after that, things got a little bit more confusing. In particular, the arrangement of the four pairs of teeth in only the front section of the lower jaw, seems to have thrown a lot people off.

There were several suggestions of Beluga whale, but they have around 40 teeth between the upper and lower jaws and clearly this doesn’t (and even if teeth had fallen out, you’d expect to see some empty sockets in the mandible). There were also suggestions of Narwhal, but they have a maximum of 4 teeth only in the upper jaw and one – or very occasionally two – form the Narwhal’s unmistakeable tusk(s). This is neither a Beluga whale nor a Narwhal.

However, the similarity of this skull to these two species did lead to speculation about whether this might be a hybrid between Beluga and Narwhal – one of the infamous Narlugas (or more accurately Belwhals). Ed Yong wrote about these real, but very rare, animals in the Atlantic a couple of years ago and I recommend having a read. If you do, you’ll discover that only one specimen is known and this is most definitely not it. As disappointing as this will no doubt be for some, we live in a world where hopes and dreams are routinely dashed against the rocks of reality, so let’s get ready to rock.

There are around 30 species of Oceanic dolphin, ranging in size from 50kg to 10,000kg. You can see that this one is a bit bigger than the specimen next to it and it has much broader and more chunky ‘cheeks’ (for want of a better term). This is something I normaly associate with the bigger dolphins that are usually referred to as whales – things like Pilot whales, Killer whales and the species in the Monodontidae that I mentioned earlier.

Most of the Delphinoidea have a lot of teeth to assist with prey capture, but this mystery object has got creative with just 4 pairs in the lower jaw (although obviously not as creative as the Narwhal). This limits the possibilities significantly, since it’s a fairly unusual condition. The other type of whales that only have a small number of teeth in just the lower jaw are the beaked whales, which primarily feed on soft-bodied cephalopods and have repurposed their teeth for competition. The mystery species has, perhaps unsurprisingly, done the very same. So, we’re left with the question of which of the bigger dolphins feeds on cephalopods and has an unusual arrangement of teeth?

The answer, as Adam Yates was the first to share, is the Grampus or Risso’s Dolphin Grampus griseus (G. Cuvier, 1812). They have between 7 and 2 pairs of teeth in their lower jaw and none in the upper. The live animals are quite heavily scarred from their interactions with those teeth.

Grampus illustration by Citron / CC-BY-SA-3.0

Stay tuned for another mystery object next week!

Friday mystery object #408 answer

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

Obviously the horns let us know that it’s some kind of bovid, but as has been noted before, there are a LOT of bovids. Overall horn configuration is a useful indicator of which general part of the bovid family tree to consider and I always find myself needing to check references to make sure I remember the general configurations.

A very helpful overview of horn morphology for the main subfamilies within the Bovide is illustrated by M. Van Bolt in a paper by Barbara Lundrigan from 1996*

Horn morphology in the main subfamilies within the Bovide. Illustrated by M. Van Bolt in Lundrigan, 1996*

Capturing the horn angle accurately in a photograph can be quite tricky, which is why I provided more than one angle:

A quick check shows that the horn shape of this specimen is distinctively Reedbuck. There are three species in the Genus Redunca, with fairly clear differences in things like the proportions of the maxilla and the shape of the orbit, but again the horns offer a clue.

Mountain Reedbucks have short horns, only in the region of about 15cm, a bit on the short side for this specimen, where they look to be around 25cm or so. The Southern Reedbuck has much longer horns in the range of 35-45cm, a bit bigger than this specimen. That leaves one Goldilocks species with horns 25-35cm long – the Bohor Reedbuck Redunca redunca (Pallas, 1767).

So well done to everyone who recognised this as a Reedbuck and special props to Goatlips who suggested Bohor Reedbuck. Hopefully the illustrated phylogeny I shared will help with future identifications.

*Journal of Mammalogy, 77(2):462-475, 1996

Friday mystery object #407 answer

Last week I finally got a chance to share a nice skull from the Dead Zoo for you to identify:

Bird skulls are always an interesting challenge, because the bill can give away some useful clues and there is a fantastic online resource available to help with their identification, in the form of SkullSite, run by Zygoma regular Wouter van Gestel. Perhaps unsurprisingly Wouter tends to be one of the first to get a correct answer when the mystery object is avian – and this one was no exception.

One of the useful features on SkullSite is the ability to do a custom search, which allows you to restrict the size range of skulls and the bill shapes to search through. This allows easy comparison between the skulls of possible taxa, making identification more straightforward, once you get your eye trained to recognise useful features.

In this case there are a few species in the same size range with similar shaped bills. The closest species in size and shape (that’s not a close relative) is the Great Bustard. However, the Great Bustard has much longer nares (the fancy name for nose-holes) than the mystery object and the bustard’s lacrimal bones (the small bones that flare out just to the front of, and above, the eye sockets) are much smaller and less pronounced than what we see in the mystery specimen.

That leaves the two species in the Family Cariamidae (or Seriemas) to pick from. The size of the specimen alone makes that fairly straightforward, as there’s around 15mm difference in the skull length between the two. However, if you want a morphological feature, the mandibular fenestra (the ‘window’ visible in the side of the lower jaw slightly back from the midway point) is proprtionally a lot larger in the Black-legged Seriema compared to that of the Red-legged Seriema.

The fenestra is small in the mystery object, while the skull is large, making this a specimen of the Red-legged Seriema Cariama cristata (Linnaeus, 1766).

A Red-legged Seriema in Reserva Ambiental, Piraju, São Paulo, Brazil. Image by Dario Sanches, 2010

I tend to think of Seriemas as the South American equivalent of the Secretarybird, since they are ground-hunting predators in scrubby environments that have a fondness for venomous snake snacks.

Both have long legs and small feet, neither fly much and both have eyelashes, as pointed out by Goatlips on Twitter:

I’d never really consider the bird eyelashes thing and it makes perfect sense for terrestrial birds foraging on the ground in arid environments to have some extra eye protection from sun and dust afforded by filamentous feathers around the eyes. It turns out this holds true for birds like Ostriches, Emus, Cassowarys, Rheas, Road-runners and the Ground Hornbills.

However, some other Hornbills that live in very different environments also have eyelashes as do those odd arboreal Hoatzins, so there must be something else going on with those lovely lashes that I’m missing.

I hope you enjoyed this bony challenge – please feel free to add your thoughts on the eyelash situation and perhaps mention any species you’ve noticed this feature in before. You never know, together we might figure out what those lashes are all about.

Friday mystery object #406 answer

Last week I gave you this mystery object from the Dead Zoo:

Usually I don’t give you clues, but for this one I thought it might be helpful in narrowing down possibilities since this specimen is faded and is probably lacking a lot of the colour features that might help with an identification. The clue wasn’t hugely helpful however, just a reference to the collector – one Major St. Leger Moore.

Palfreyman1414 and salliereynolds made the inital observation that this is an ungulate, but there are very many ungulates and that doesn’t narrow it down by much. Goatlips went on a bit of an adventure with Major St. Leger Moore and found some useful information – the Major served in the 9th Lancers who were posted to India during his service, in which time he picked up polo (which he was apparently involved in appropriating for Britain) and most likely this particular trophy.

With this information it becomes a bit easier to start narrowing down likely possibilities – there are around 21 species of bovid in India and only one of them looks anything like this – the Chinkara or Indian Gazelle Gazella bennettii (Sykes, 1831), which Goatlips hinted at with a cryptic reference to a cricketer. Of course, there are plenty of gazelle species in Africa, which Major St. Leger Moore may have visited outside his time in the military, since he was a keen sportsman and recognised as being able to “shoot straight”.

Checking the features of the Chinkara helps to add confidence to the identification. According to the ADW the Chinkara is:

…characterized by a sandy, yellowish and red colored fur with a pale white ventral region. Facial markings are well developed: they have a dark brown or black forehead and a light face with dark stripes and a noticeable nose spot. Fur color varies seasonally. In the winter, Indian gazelles are a dark grayish sandy color, and there is a distinct brown band edging the white ventral area of the torso. In the summer, the fur is a darker brown.

Indian gazelles have straight horns with prominent rings and tips that are slightly out-turned. Horns are found on both males and females, although they are relatively shorter in females. Sub-adult males are hard to distinguish from females because of their intermediate horn length. Horns can reach lengths of 250 to 350 mm in adult males. Female horns are usually half the length of and thinner in width than male horns and have less prominent rings. Average male horn length of the subspecies Gazella bennetti fuscifrons and G. b. shakari is 256.6 mm. Females of these subspecies have an average horn length of 184.7 mm.

McCart, D. 2012. “Gazella bennettii” (On-line), Animal Diversity Web. Accessed April 22, 2021 at https://animaldiversity.org/accounts/Gazella_bennettii/

While the colours preserved on the specimen aren’t quite good enough to provide much assurance, the details of the horns (especially when compared to other gazelle species, that often have much longer and more lyrate horns) correspond very well with the Chinkara. Not a certain identification, but pretty convincing.

So well done to Goatlips for some nice detective work!

Friday mystery object #405 answer

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

There was no scale and admittedly there’s not much of the specimen visible, but I didn’t think that would pose much of a problem. And I was right. Tony Irwin immediately indicated the identity of this rather rare specimen with the anagram:

Maybe found it – in rosy pea?

The “in rosy pea” unscrambles to Aepyornis which is the generic name for the Elephant Bird.

Of course, this isn’t a complete Elephant Bird, it’s only an egg (had to get some Eastery link in there somehow). Elephant Birds have been extinct for about 1,000 years, so surviving eggs are very rare, hence the special fancy box. Here’s the actual egg:

The total length is just shy of 1 foot at 29.6cm, making this one of the largest eggs ever laid by any animal. There are other Elephant Bird eggs that are a bit bigger (up to 34cm), but no other type of animal ever laid a bigger egg, even the vast sauropod dinosaurs laid eggs that were smaller than this.

I’m not going to tell the story of this specimen here, since it’s already on the National Museum of Ireland’s website. If you have a read of that, you’ll see that this specimen is from the southern end of Madagascar (the island on which these birds lived) and that plus the particularly large egg size suggests that this is from Aepyornis maximus I. Geoffroy Saint-Hilaire 1851.

This is not the first time I’ve dealt with Elephant Bird eggs, since I borrowed one from David Attenborough for an exhibition at the Horniman Museum about 5 years ago, which I talked about here.They are remarkable objects and it’s strange to think of something as fragile and seemingly ephemeral as an egg surviving intact for over a thousand years.

So well done to everyone who worked out what this mystery was – eggcelent work!

Friday mystery object #404 answer

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

It wasn’t really much of a challenge for the usual suspects, with everyone recognising this as a Common Hill Myna Gracula religiosa Linnaeus, 1758.

However, my reason for picking this as a mystery object wasn’t for the challenge offered, but as an illustration of just how frustrating the taxonomy of old collections can be. Everyone recognised this bird, which is not a huge surprise, given how familiar this species has become due to the pet trade, but anyone looking at this specimen on display would probably struggle to match the specimen to the species considering the label that was attached:

The common name here suggests that the specimen is from Malaysia, then the scientific name suggests Java, but then the locality associated is just “East Indies”. The genus name does at least bear a passing relationship to the modern specific name (“Eulabes” means “pious” or “devout” while “religiosa” is self-explanatory). Similarly “Grackle” does hold a clue to the modern Genus name of “Graculus“. Most confusing.

To make things worse, the Graculus is now recognised as forming a species complex across Asia, so it would be good to narrow down which subspecies this specimen belongs to:

Distribution of the various species and subspecies within the genus Gracula. Image by L. Shyamal, 2009

The pattern of coloured feathers on the neck and head on the Dead Zoo specimen appears to match G. religiosa intermedia most closely, so when I eventually reach the stage of rewriting labels for specimens on display, I’ll do my best to improve the information. Unfortunately, this will probably need to happen for around 75-80% of the collection, so no pressure…

Friday mystery object #403 answer

Last week I gave you this rather beautiful mystery object from my old place of work, the Horniman Museum:

It’s the only example I’ve seen of this species that’s been prepared to show it from this perspective – and it’s pretty special. There were plenty of answers, with most people on the button with the what it’s from.

Goatlips was the first to jump in with the broader identification, but palfreyman1414 was first to get the the species. The highly reflective, pearly surface (comprised of mother-of-pearl or nacre) provides a bit of a clue. This is a transverse section of a Pearly or Chambered Nautilius Nautilus pompilius Linnaeus, 1758.

Normally when people take sections through a Nautilus they take a sagittal section, to show the near perfect logarithmic spiral formed by the shell as it grows, so the transverse section offers a perspective that’s much less familiar:

Image of Nautilus shell in sagittal section taken by Chris 73, 2004

Since the transverse section is so unusal it’s quite difficult to find good references for identification. However, with a good imagination you can work out what’s going on with the relative sizes of the chambers and how much they overlap, to get a sense of the shape in the coronal plane (that’s the line through the body that gives us a transverse section).

That said, it’s easy to recognise that this shell is from the genus Nautilus rather than Allonautilus thanks to this image from Jereb and Roper, 2005:

Shell characters of genus Nautilus vs. genus Allonautilus. After Jereb and Roper (2005), modified by Antonov, 2008

There is also a paper by Ward and Sanders, 1997 with the same sections shown, plus an additional illustration of N. macromphalus which lacks the thick side walls seen in N. pompilius. From what I’ve seen I’m reasonably happy that the specimen is a Pearly Nautilus, but the taxonomy of this ancient group of cephalopods is still quite poorly known, so I’ll hang on to a shred of doubt for a while.

Friday mystery object #402 answer

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

Skull length approx. 170mm

Of course, you’d only recognise this as being awesome if you knew what it’s from, since apart from bit of a weird shape to the top of the skull, it looks like it could be from a chunky galliform or perhaps a Screamer. However, this skull is from a type of pigeon.

Of course, it’s not from one of your boring standard sorts of pigeon, this skull is from a very special pigeon. Adam Yates pipped everyone to the post in the comments, identifying that this is the skull of a Rodrigues Solitaire Pezophaps solitaria (Gmelin, 1789).

If you’re not familiar with the Solitaire, it’s the closest known relative of the Dodo and, like its cousin, it was large, flightless and it’s now extinct. The similarity doesn’t stop there, as both were endemic to a small, unpopulated island in the Indian Ocean, hundreds of miles east of Madagascar and both were driven to extinction not long after humans first visited the island and dropped off goats, pigs and (inadvertantly) rats.

The closest living relative of both of these extinct birds is the Nicobar Pigeon, found in a string of islands in the Bay of Bengal. While the Nicobar Pigeon is colourful with iridescent feathers that shift colour in changing light, the Solitaire was reported to be a a grey and brown bird about the size of a swan.

The colourful Nicobar Pigeon

A handful of reports are the only real source of information about the plumage and general appearance of a live Rodrigues Solitatire, with just one illustration ever being made by someone who has seen the bird. That was François Leguat, a French naturalist who arrived in Rodrigues in 1691. His artistic skills were more stylistic than descriptive, but he did describe the Solitatire’s plumage as beautiful.

Le Solitaire by François Leguat, 1708

Fortunately, we know a lot more about the bones of Solitaires than we do their plumage, thanks to large fossil deposits of the bird uncovered during the Transit of Venus observations from Rodrigues in 1874. The Dead Zoo specimen is a composite skeleton made up of bones brought back from that expedition and presented to the Museum on behalf of the Royal Society.

My favourite bit of the skeleton is probably the fighting knobs on their wrist bones. They’re a little hard to see here, but apparently the Solitatire’s could be quite aggressive and attack with their wings, which had presumably become repurposed for competition (and perhaps defense) since they were no longer needed for flight:

There will be more mysteries next week, but before you go I wanted to drop in a reminder that I’ll be doing a talk about Dismantling the Dead Zoo this evening at 7pm GMT. If you’re interested in finding out more about how to take apart whales and wrangle hippo heads, why not sign up and join in for free?

Friday mystery object #401 answer

Last week I gave you this gnarly looking skull from the Dead Zoo to identify:

I didn’t think it would be a difficult one, especially since it is a critter I’ve used as a mystery object before (although that was over 10 years ago!)

As I suspected, everyone figured out that this is the skull of an Alligator Snapping Turtle, but things have become a bit more complicated than they used to be over the last decade, since the single species that used to be in the genus Macrochelys has since been split.

The amount of splitting has varied, but at the moment it seems to have settled on two species being recognised; Macrochelys temminckii (Troost, 1835) and Macrochelys suwanniensis Thomas et al., 2014.

Variation of the squamosal in A. Macrochelys temminckii and C. Macrochelys suwanniensis. Adapted from Thomas et al. 2014. Zootaxa 3786(2):141–165

One of the key diagnostic features identified to differentiate between them is the angle of the squamosal (the bit of bone with the arrow pointing it above). In M. temminckii the angle is greater than 90° whereas in M. suwanniensis it’s less than 90°.

That suggests to me that the Dead Zoo specimen is probably the Suwannee Snapping Turtle Macrochelys suwanniensis Thomas et al., 2014. The only problem with this identification is that the collection locality is simply “Mississippi”, which doesn’t fit with the Suwannee river distribution of the species.

I’ll need to go back and look at a few other skeletal characters to confirm the identification once I’m back in the Dead Zoo, but my guess is simply that the collection locality wasn’t accurately recorded, since the specimen came from the natural history supplier Edward Gerrard rather being collected and properly documented by a researcher.

It certainly wouldn’t be the first time a representative locality has been given for a specimen meant for display or teaching rather than research!

Friday mystery object #400 answer

Last week we hit the 400th mystery object, which was this specimen from the Dead Zoo:

Horned beasties can be tricky since there are over 140 species in the Bovidae. There is quite a lot of diversity in size and in horn shape, but there are some general patterns, with spirals, twists, curves and recurves. A good place to trawl through for comparisons is the Animal Diversity Web, which has plenty of images.

However, this is one of the better known species, with nicely lyrate horns, so quite a few people recognised it without having to go searching. This is a Springbok Antidorcas marsupialis (Zimmermann, 1780), a South African antelope that has given its name to the nation’s rugby team. Well done to everyone who figured it out, particularly Goatlips, who got there first!

This specimen is one of 333 game heads that we’re in the process of decanting from the Museum, as part of a project that includes moving thousands of invertebrates and birds, as well as a couple of whales. If you’re interested in how we’re dealing with the game heads we recently reported on it at the NatSCA Conservation Twitter conference, which I’ve shared below:

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Friday mystery object #399 answer

Last week I gave you this cute little bird of prey to have a go at identifying:

It didn’t prove to be much of a challenge, but I was impressed by the answers nonetheless. In particular, the first answer by Hilary Blagbrough is both a delightful poem and correct:

A little hunter from the east
that feasts on juicy dragonflies
In black and white is smartly dressed
No colours seen on legs or chest
Who is this with the panda eyes?
That of its sort, is not the least

So this mystery object is a bird of prey found in Asia. It’s very small and primarily feeds on insects, although it can take small mammals, reptiles and other birds of a similar size or smaller than itself. Since it’s a falcon, but smaller than expected, it’s called a falconet.

There are a few species of these falconets that are quite similar. However, as Hilary says, this one doesn’t have any colours on the legs or chest and it’s just black and white, without any patches of colour and it has discrete patches of black around the eyes. These features all suggest that this is the Pied Falconet Microhierax melanoleucos (Blyth, 1843).

There were several correct identifications on Twitter and more in the comments on the blog after Hilary’s poetic post. So well done to everyone who figured it out!

Friday mystery object #398 answer

Happy 2021 – I hope you had a great celebration!

Last year I gave you this mystery skeleton for you to have a go at identifying:

That erect stance and those super-short and chonky wing bones are a dead giveaway that this is one of those charismatic flightless waiter birds (and before you ask, yes the “i” is intentional).

There are around 20(ish) species of penguins or pengwings if you’re Benedict Cumberbatch.

Although the various species look superficially similar, with their black and white base colour scheme and tubby yet streamlined shape, they do have some distinguishing characteristics. Unfortunately, the most obvious relate to plumage and that’s missing here.

Size can help with narrowing it down – and this particular specimen is small. Admitedly it’s hard to tell that without a scale bar, but the large species have relatively small skulls in proportion to their body size, so they can be ruled out.

Bill length and shape can also provide some good indications even from non-skeletal birds and you can of course check out my favourite online resource (SkullSite.com) to see skulls of most of the main penguin genera, if not all the species (yet!). In the comments, James Bryant and Wouter van Gestel (creator of the aforementioned SkullSite) recognised that this is a Little, Blue or Fairy Penguin Eudyptula minor (J.R.Forster, 1781).

Little Penguin in the Melbourne Zoo. Image by fir0002, 2009.

This is the smallest species of penguin, it has breeding colonies in Australia and New Zealand and the population on Phillip Island has become a bit of a tourist attraction. They feed on small fish, like anchovies and pilchards or small invertebrates including squid and jellyfish.

There will be more mystery objects to come for 2021 – let’s hope this year works out better for everyone than 2020…

Friday mystery object #397 answer

I’m going to start this week’s blog mystery object with an apology – it’s going to be a short one, as I’m in the final throes of taking down our Fin whale, which means I’m exhausted after several long weeks of hard graft. Check out the #DeadZooDiary hashtag on Twitter if you want to get an idea of what’s involved.

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

It wasn’t too difficult to narrow it down to one of a few species, thanks to the very distinctive knee region.

There are only a small number of birds that have adopted this extreme elongation of the cnemial crest on their tibiotarsus and patela. These are all specialist foot-propelled swimmers that need that long lever to help power their diving strokes. This is a feature limited to just the grebes and the loons/divers.

Most people figured out that this is the skeleton of one of the loons. The skull provides some clues, but unfortunately the angle of the photo doesn’t make it easy to figure out which of the five species it is.

The scale does rule out the larger of the species (Gavia immer or G. pacifica), but there are three other possibilities. For me the postorbital region suggests that this is the Arctic Loon Gavia arctica (Linnaeus, 1758), which fortunately matches the label.

I hope you enjoyed this weird kneed bird – congratulations to Goatlips and everyone else who figured it out!

Friday mystery object #396 answer

Last week I gave you this bumpy little critter to identify:

I think everyone recognised the mystery object as some kind of Nudibranchia or sea slug. The general type of sea slug is identifiable by that ring of gill filaments known as a branchial plume that you can see at the top of the specimen. This is characteristic of the suborder Euctenidiacea, also known as the dorids.

I called it bumpy, but if you look closely you’ll see that the bumps are pinched at the base and actually look rather warty. There’s a clue in that – and several of you spotted it.

There were a number of wart-related nudibranch suggestions that were close, but jennifermacaire was spot on with her comment:
Doris has warts?

This is indeed a Warty Dorid or Doris verrucosa Linnaeus, 1758.

Warty dorid, image by AndyT

This specimen isn’t quite as faded as everyone expected – they’re usually a fairly muted orange, yellow or a greenish colour, not too different to the mystery object. This probably serves as camouflage against the background of the Warty Dorid’s favourite food, the Crumb-of-bread Sponge, which also varies in colour from bright yellow to darker shades depending on the depth of the water in which they live.

More mystery objects next week!