Tag Archives for Natural history

Friday mystery object #284 answer

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

mystery284

It’s quite a distinctive structure and very particular to one particular group of mammals. It is of course an external auditory meatus (or ear hole as it’s more commonly known), but instead of opening directly into the auditory bulla (the inflated bony bulb that holds the ear bones) it has a long and robust tube.

Lee Post, Daniel Calleri & Dan Jones and Allen Hazen recognised this characteristic feature as belonging to a Beaver and Richard Lawrence went one better and narrowed it down to Castor canadensis Kuhl, 1820 – an identification that I agree with having seen the whole skull:

beaver_skull

I’m not sure if there’s any real functional reason for the ear tube, but it looks to me like it might be a “spandrel” a feature that’s an artefact of another adaptive feature – in this case the articulation of the mandible.

beaver_jaw

Gnawing through a tree trunk is no easy task, so it’s not surprising that the Beaver has some serious adaptations to deal with the work involved. Unlike carnivores, which have a fixed lateral mandibular articulation powered mainly by the temporalis muscles, rodents have a dorso-ventral articulation usually powered by the masseter muscles, which allows the jaw to move backward and forward. In the Beaver the sagittal crest suggests that the temporal muscles are more involved than usual which, with the orientation of the articulation, may necessitate the ear tubes as lateral braces against which the mandible can secondarily articulate. That’s my guess…

Great work on identifying this specimen using very limited information!

Friday mystery object #283 answer

Last week I gave you this zoomed in picture of a specimen to have a go at identifying:

mystery283

It was a bit tricky, so I also gave you this bonus clue to help:

mystery283_bonus

I was impressed to see that, despite the limited information available from the images provided, many of you managed to work out that this shows the lightweight ‘honeycomb’ structure that supports the casque of a hornbill.

That was the first challenge but, as ever, I was keen to see if you could get the identification to species – far more of a challenge considering the lack of a side view of the skull and lack of a scale. To make up for that I’ve decided to provide the necessary image here:

Ceratogymna atrata skull

I won’t say what species this is in this post, as I normally would, just to give some more of you a chance to make the identification yourself. However, what I will say is that the very first response by Wood contained a link to an image of the correct species and later to a blogpost featuring this very specimen. In that post there is a discussion about the appearance of the casque, with speculation about whether it had been damaged during preparation, resulting in its appearance. However, as Richard Lawrence pointed out, this appearance is actually normal for the skulls of several species of hornbill.

I will also say that the discussion between Daniel Calleri & Dan Jones and Richard Lawrence about whether it was a hornbill from a genus starting with A or B was interesting and I initially thought it was an A, but am now convinced that it’s a C.

If you’re desperate to know which species it’s from, here’s a link to the skullsite.com page about it.

 

Friday mystery object #283

This week I have a mystery object for you that’s a bit different from the usual. Any idea what this zoomed in picture is showing?

mystery283

It’s probably a bit of a tricky one, so if you want an extra image that makes it much easier you can click on this link for a bonus clue.

Please leave your suggestions in the comments below – I’d love to find out your thoughts and let me know if you needed the clue. Have fun!

Friday mystery object #282 answer

Last week I gave you this mystery object supplied by Dr David Hone:mystery282

This is the premaxilla of a fish, but that doesn’t narrow things down much, since there are 28,000 species of bony fish, leaving a huge range of possibilities.

There were several suggestions of Wolf Fish, which is what I originally thought it was myself, but that’s not what it is. Then the suggestions of various Wrasse species started cropping up – which is a lot more likely.

My first look at Wrasse teeth came when I tried to identify the fish used in the Horniman’s Merman:

SONY DSC

There are a lot of Wrasse, over 600 species in fact, so it can be hard to narrow down the species, especially when few comparative specimens are available.

One very helpful osteology resource for identifying fish from their bony bits is Osteobase which lets you pick a bone and start making comparisons. It’s worth keeping in mind that you need to really explore the taxonomic tree on the left of the page to get a real appreciation of how useful it is – so for example, after selecting the premaxilla, if you look at the Perciformes (the Order containing the Wrasse) you see a huge range of premaxilla specimens that help narrow down the bone you’re trying to identify.

This clearly shows that the Labridae is definitely the right family for the mystery object and the Mexican Hogfish Bodianus diplotaenia (Gill, 1862) is a very close match.

So congratulations to Richard Lawrence who I think has it right, especially since the specimen was found within the range of this species. I hope you all enjoyed the challenge!

Friday mystery object #281 answer

Last week I asked for your opinion on this mystery object:

mystery281

It had originally been identified as Boa constrictor and then reidentified as Green Anaconda, but I didn’t believe either of those options.

There was some activity in the comments, from the initial observation that it’s a snake from Wood, to Andy Mills’ suggestion of Python, with palfreyman1414 and Daniel Jones and Daniel Calleri’s discussing how to tell whether it’s a boid or pythonid.

In fact, palfreyman1414 did some sterling work tracking down characteristics to help distinguish between these commonly confused groups, with this handy comment:

“The postfrontal bone, usually present, borders the orbit behind, rarely also above, and in the pythons a supraorbital bone is intercalated between it and the prefrontal bone.”

And..

“Boids are, however, distinguished from the pythons in that none has postfrontal bones or premaxillary teeth”

The character of the presence or absence of teeth in the premaxilla (the frontmost bone of the upper jaw in the midline of the skull) is particularly useful, although it’s not unusual for the premaxilla to fall out of snake skulls.

The postfrontal character is a bit less obvious and I’m not fully convinced by it – not because there isn’t an extra bone in the pythons compared to the boas (there is), it’s just whether it’s a postfrontal, a supraorbital or a post orbital. That depends on the reference you read. To help get an idea of the bits we’re talking about, I’ve highlighted them here (purple for premaxilla, pink for the bit missing in boids, call them what you like):

mystery281_bones

It’s probably worth mentioning that Anacondas are members of the boid family, so it’s clear that this specimen is a pythonid rather than a boid. But that doesn’t tell us what species it is (if you want to see a Boa constrictor skull there’s a video of one here).

Comparing overall skull shapes in snakes is not very effective, since the skull is very loosely articulated to allow it to deform when swallowing large prey, so when mounted they can be very variable in shape. Because of this you need to compare the shapes of the various bones that make up the skull to narrow it down.

There is a very helpful image resource called BioLib that has validated photos of skulls amongst other images, so it’s well worth checking out. Trawling through I didn’t manage to find a species with the same shapes in the nasals, prefrontals, frontals, parietals and supratemporal – but I did discover a specimen photo by Jean-Christophe Thiel that fit (not to mention a previous mystery object) – so I’m fairly confident that this is a Royal Python Python regius (Shaw, 1802).

Many thanks to everyone for their comments – it’s been a fun challenge where I know I’ve learned an awful lot. I hope you have too!

Friday mystery object #280 answer

Last week I gave you this crocodilian skull from the Grant Museum of Zoology to see if you had any thoughts about which species it might be:

mystery280

It turns out that you did indeed have some excellent thoughts about the identification, with Cindy Nelson-Viljoen immediately getting it right, with astute observations from David Godfrey and palfreyman1414, plus another correct responses from Joe Vans (as well as Tone Hitchcock and Henry McGhie not via the comments section).

This is a skull of the Dwarf Crocodile Osteolaemus tetraspis Cope, 1861. It’s small size is the first clue, but given how crocodiles grow this could pass as the skull of a young individual of a much larger species. As David Godfrey pointed out, there may be some paedomorphism (where adults look like juveniles) in effect in this species, since the adults as well as being small, have relatively short snouts and big eyes – which are features of juvenile animals as you can see in this display of crocodile development I did for Dinosaurs! Monster Families just before leaving the Horniman:

Croc_development

Part of my reason for wanting to show you this specimen was to force myself to look for some good online resources to get more familiar with crocodilian morphology. As it turns out, I did find a very useful comparative image, which shows the size and shape of the mandibular foramen (a large gap between the bones in the side of the lower jaw) is a helpful feature:

In this species the foramen is small, which when considered with the overall proportion is quite distinctive. Of course, this image does not include all 24(ish) living crocodilian species, but it does provide a pretty good range. Hopefully this will help speed up future croc skull identifications, at least allowing certain species to be discounted.

If you have any good tips for crocodile identification please share below!

Friday mystery object #280

Last week the answer to the mystery object was a Gharial – a very weird crocodilian from India. I realised that I didn’t know much about identifying the Crocodyliformes, so I thought it might be fun to have a go at working out what this species might be:

mystery280

As always, I would love to hear your thoughts below and let’s see if we can find some good diagnostic features!

Friday mystery object #279 answer

Last week I gave you this mystery object to identify:

mystery279

It’s the kind of thing you find in museum collections quite often, but it will commonly be misidentified – especially in anthropology collections where (in my experience) it will commonly be referred to as a claw or big cat tooth.

However, nobody who commented went down that route, recognising that the hollow base and well defined crown indicates that it’s an open rooted tooth of some sort. In mammals an open root at this size that would suggest a pig tusk or perhaps a whale tooth, but this isn’t mammalian.

In fact, this tooth is from something even less cuddly than a whale, something crocodilian. This was recognised first by Carlos Grau, but others who came to the same conclusion included Jonathan Larwood, Daniel Jones, palfreyman1414, Wouter van Gestel and Charne. More specifically, this tooth is from a Gharial, Gavialis gangeticus (Gmelin, 1789). This Gharial from the Grant Museum of Zoology in fact:

mystery279_Gharial

Grant Museum of Zoology Specimen LDUCZ-Y215

Gharial teeth are a bit less conical than the teeth of most crocodiles and alligators. Presumably the curve helps prevent their main diet of fish from getting free when caught.

Gharials are sexually dimorphic, with the adult males bearing a big rounded bony  knob on the end of their rostrum, this is where the name Gharial comes from, as this feature resembles a local earthenware pot called a “ghara”. Sadly, these distinctive crocodilians are critically endangered, with just a few hundred left alive in the wild. They are affected by habitat loss, egg theft and use in traditional medicines.

More mysteries next week and if you fancy hearing me talking about animals you might be interested in coming to Animal Showoff at the Grant Museum of Zoology next Thursday evening!

Friday mystery object #278 answer

Last week I gave you this mystery object from the Grant Museum of Zoology to get your thoughts on:

mystery278

Most people spotted that this was a canid of some sort – but there was a lot of discussion about exactly what sort.

Allen Hazen made an interesting observation about the reduced second molar (missing in the specimen, but the socket shows that it was there and smaller than you’d expect from most dogs), plus the remarkably convex facial profile. Useful observations that have a bearing on the identification.

The short and broad muzzle, combined with the convex skull and distinctive molar morphology led Latinka Hristova to suggest Dhole, an identification agreed with by Lupen, palfreyman1414, Richard Lawrence, joe vans, Henry McGhie – and myself as it turns out.

Dhole (Cuon alpinus) by Kalyanvarma

Dhole (Cuon alpinus) by Kalyanvarma

The Dhole Cuon alpinus (Pallas, 1811) is an endangered Asiatic Wild Dog, that hunts in clans and feeds on a variety of medium to large mammals that are usually killed after an extended chase.

I’d not seen the skull of one of these before, but I was aware that they have a convex profile, so it was my immediate suspicion when I saw the mystery object and the species was confirmed by the unusually simple structure of the first molar and very reduced second molar, which are almost cat-like in their adaptation for shearing meat.

All in all, an exciting skull to find – and there are other unidentified canids in the same box that I’m itching to take a look at, so keep your eyes peeled for more mystery mutts.

Friday mystery object #277 answer

Last week I gave you this pretty cool skull from the Grant Museum of Zoology to identify:

mystery277

On Twitter the prevailing hypothesis was that this is the skull of an Alien Xenomorph, which was also proposed by Daniel Calleri, but most the comments here on Zygoma were a bit more down to Earth.

The identification started being narrowed down by Sisyphus47 and palfreyman1414 who recognised it as a reptile, which was narrowed down further by joe vans to a fossorial (or burrowing) lizard.

Allen Hazen, John D’Angelo and Daniel Calleri took it another step further and identified this as an amphisbaenian or worm lizard, but Rebecca Watling went even better and identified it as the skull of a Red Worm Lizard Amphisbaena alba Linnaeus, 1758. The morphology is very close and the size is right, so that’s the identification I’d also reached.

Amphisbaena alba by Diogo B. Provete

Amphisbaena alba by Diogo B. Provete

I’ve talked about Amphisbaenia before, but this one is a good bit bigger than most other species and the skull is oddly similar to that of a Weasel. I’m not really sure why, because the diet of these strange reptiles is very poorly known. It seems likely that they’ll eat invertebrates and small vertebrates, presumably in burrows, which does actually sound similar to a Weasel.

Weird, but pretty awesome!

Friday mystery object #277

This week I have a pretty interesting little skull from the Grant Museum of Zoology for you to try your hand at identifying:

mystery277

Any ideas what this might be from?

As usual you can leave your answers below – I have a feeling that some of you will find this easy, so please try to be a bit cryptic with your suggestions. Have fun!

Friday mystery object #276

This week I have a mystery specimen for you that was only identified only as “Pygostylia” when it came back from being conserved:

Click for large image

It look a few minutes for me to work out what family this bird belongs to, because it’s been treated with alizarin and it just looks plain weird (if you want a bit more information about this sort of preparation check out my latest Specimen of the Week on the Grant Museum of Zoology blog). I still haven’t narrowed it down to genus yet, so your thoughts would be much appreciated. Have fun!

Dinosaur Eggshibition!

It’s been a while since I last wrote much on my blog, apart from the regular Friday mystery object. Mainly that’s because I’ve been busy getting to grips with a new collection at the Grant Museum of Zoology, where I am now the Curator. Just before I left my previous job at the Horniman Museum & Gardens I curated an exhibition that has a nice Eastery link (which will become apparent), that I thought might be worth writing about.

The exhibition is a touring show developed under the title Hatching The Past, which was brought to my attention by palaeontologist, science blogger and old friend Dr Dave Hone who’s a lecturer at Queen Mary University of London. I went to the Città della Scienza in Naples with some colleagues from the Horniman to take a look (which is an interesting story in its own right, since the main part of the museum had been burned down by the Mafia in 2013).

Despite the suboptimal exhibition space in Naples (thanks to the fact that the building it was meant to be displayed in was a pile of charcoal), the quality of the science, the objects in the exhibition and the vibrant and exciting artwork by the awesome palaeoartist Luis Rey made it well worth considering for the Horniman, which tries to get in a blockbuster temporary exhibition every year.

This exhibition focuses on the eggs, offspring and parental care of dinosaurs. A family focus is right up the Horniman’s street, and that’s what led to the change in the exhibition title, to bring more focus on that family element, without losing sight of the DINOSAURS!

Tarbosaurus

Star of the exhibition

Of course, making an exhibition intellectually fit into a museum takes more than just changing the name, so the temporary exhibitions at the Horniman include objects from the permanent collection, with links to activities and other content. So while working out my notice from the Horniman I was feverishly selecting objects and writing text to help build that link before I left.

Horniman_case

It has to be said that seeing members of the public engaging with your work is incredibly satisfying, so when the exhibition opened in February I was delighted to see people reading my text and really getting interested in the objects I’d picked to tell the story of parental care in living animal groups.

Aepyornis_egg

I was also keen to take the opportunity to help the Horniman build closer links with one of their patrons (and a living legend for pretty much every naturalist out there), Sir David Attenborough, who kindly agreed to loan the Elephant Bird egg he found when filming Zoo Quest in Madagascar. This for me is the ultimate version of an egg hunt.

Have a great Easter weekend – I hope you get all the eggs you could ask for!

Friday mystery object #274 answer

Last week I gave you this ungulate skull to try your hand at identifying:

mystery274

It isn’t made any easier by the fact that it’s a female, so it lacks the horns or antlers that make identification easier. As with many ungulates it looks a bit sheepy (as I’ve mention before), but it has some clear indicators that helped you rule out what it’s not.

Jake spotted that the size was about right for a Roe Deer, but the auditory bullae (the bulbs on the underside of the skull that house the ear bones) are too massive and the proportions of the braincase are quite different.

Joe vans also ruled out deer, since it lacks lacrimal pits (large openings in front of the eyes that hold scent glands in cervids). Joe also noticed that the mandible is extremely pinched in just behind the incisors.

The incisors themselves caught the attention of Allen Hazen, who noted the extreme size of the first incisor, which he correctly recognised as being a bit of a giveaway to some people, although only when considered in the context of a variety of other features.

While Daniel Calleri summarised these odd features and added the observation of the decent sized occiptial condyl (the place where the atlas vertebra attaches to the skull) and small paracondylar processes (the bony extensions either side of the occipital condyl and just behind the auditory bullae).

These sorts of observations are exactly what are needed to differentiate between species that are very similar in overall morphology. However, without either an excellent reference collection, or even better, a well researched key, it’s almost impossible.

Fortunately, there is a skull key for a subset of Antelope that occur in Tanzania, created by the Field Museum and the mystery object this week happens to be from a genus present in Tanzania. I’d recommend having a go at using the key, but if you’d rather just find out the answer I’ve provided a link to what it is here. Have fun with the key and enjoy your Easter!

Friday mystery object #274

Last week I talked about ungulates in collections being incorrectly identified as sheep. This week I have a specimen for you that is also not a sheep, although it does look a bit sheepish. Can you work out what it is?

mystery274

You can leave your thoughts in the comments section below – I’m not sure they need to be cryptic, but it certainly adds to the fun!

Friday mystery object #273 answer

Last week I gave you this mystery object to get your input on:

mystery273

It was labelled Ovis aries, which didn’t ring quite true for me, so I thought it would be good to see if you also had other ideas, since I’ve noticed that there is a tendency for ungulates of a certain size in museum collections to be assumed to be Sheep.

In other museums I’ve found female Red Deer, Gerenuk and on one occasion even a Badger skull that had been labelled “Sheep”.

mystery273-gerenuk

Labelled “Sheep” but actually a Gerenuk.

This is what a sheep looks like:

mystery273-sheep

You’ll probably notice the “Roman nose” that is quite distinctively sheepy, it also has no gaps between the premaxilla and maxilla and there is a small depression in front of the eye.

When you look underneath, one of the key things that jumps out is the difference in size of the auditory bullae (mystery on the left, sheep on the right):

mystery273-mystery_and_shee

So I’m pretty sure that the mystery object isn’t a sheep, but what is it?

There were lots of suggestions of exotic and interesting ungulates, but after looking at the skulls of a huge number of ungulates I can to the conclusion that Latinka Hristova and Jake were on the right track with the simple suggestion of Goat Capra hircus (Linnaeus, 1758).

Taking a look at Goat specimens on the incredibly useful Mammalian Crania Photographic Archive has convinced me that this is what the mystery object actually is. Not a million miles from Sheep I suppose, but they are different and it’s helpful finding some small differences that help distinguish between them.

Thanks for your input!

Friday mystery object #272 answer

Last Friday I gave you this skull to identify:

mystery272

It was a bit of mean one, because although the family is fairly distinctive, it has poor species representation in online resources or indeed the literature.

The cranium is quite low and long, with some similarities to an otter, but the rostrum (or muzzle) is a bit too narrow and the teeth aren’t quite the right shape. Also the orbits are orientated more vertically, whereas otters have orbit that are at more of an angle so the eyes are closer to the top of the head.

The overall shape, dental configuration and median lacerate foramen all suggest it’s a member of the Herpestidae.

Narrowing down the species was a step too far however, after all, there are around 34 species spread across Africa, Madagascar and Asia and Europe and they are generally quite similar in cranial morphology, with only a few species having good descriptions of the skull.

To help challenge the lack of images of mongoose crania online, I’m pleased to say that this specimen does have an identification – it’s a Ruddy Mongoose Herpestes smithii Gray, 1837. While the name Ruddy Mongoose makes it sound like it’s annoyed me, it actually refers to the reddish-brown of its coat.

A Ruddy mongoose from Daroji wildlife sanctuary in Karnataka, India. By Kalyanvarma, 2009

A Ruddy mongoose from Daroji wildlife sanctuary in Karnataka, India. By Kalyanvarma, 2009

This species is endemic to India and Sri Lanka, where it lives in dry, forested hills and feeds on pretty much anything it can get hold of, from snakes to bird eggs. As with other mongooses (or should that be mongeese?), they have a mutation that prevents snake neurotoxins from bonding at receptor sites, meaning that they are immune to some types of venom – pretty handy if you’re going to eat snakes!