Friday mystery object #410 answer

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

There was a lot of discussion about what it could be, which is unsurprising, since there are a LOT of fish species – with over 34,000 possibilities. This one proved additionally confusing, since it seems to have no teeth, as mentioned in the comments by Adam Yates. Fortunately, Wouter van Gestel flagged that some species with several rows of teeth tend to lose those teeth during preparation if it’s not done with sufficient care, which is useful to know.

I picked this object because I get a lot of requests for identifications of fish skull bones and this specimen is helpful, as it has the various bones of the skull labelled individually:

This specimen also happens to be a fish from a family that often comes up for identification. The neurocranium (or braincase) has a fairly characteristic shape in these fish, which is best seen from above on the skull (although unfortunately it’s not labelled in the image below):

The neurocranium tends to be a bone that gets found on beaches quite commonly. In fact, I have had a similar neurocranium as a mystery object in the past, so you may have seen one here before:

This shape is what I expect to see from members of the True Cod family, the Gadidae. Clearly a lot of other people recognised this as well, since Chris kicked off the comments with references to Gadus, Cod and Pollock and there were lots of suggestions of Cod and Pollock (AKA Saithe) on Twitter:

Unfortunatley, this is where it gets more complicated. Differentiating between different Gadids isn’t always easy. The size suggests it will be one of the larger members of the family – Cod, Haddock or Pollock being the main focus. Haddock is easy enough to dismiss, since they have small mouths, with lower jaws (composed mainly of the dentary and articular bones) that don’t project as far as we see in this specimen.

After that it gets really quite tricky – to the point where I am now doubting the original identification we have for the mystery object. This specimen was labelled as an Atlantic Cod Gadus morhua, although the original identification when acquired from Rowland Ward was Pacific Cod Gadus macrocephalus. But after a lot of searching of images from some pretty reliable online resources, I’m increasingly convinced that the specimen is a Pollack, Pollock or Saithe Pollachius pollachius (Linnaeus, 1758) – N.B. I’m ruling out P. virens since the lower jaw proportions are wrong.

The reason I’m thinking Pollack is based around a few small features of a couple of the bones of the skull. In particular, I’m interested in the shape of the hyomandibular and the opercular (Osteobase has these elements for Cod, but unfortunatley not Pollack). To give you an idea of the differences, here are the Cod elements (superimposed in blue) alongside the same bones of the mystery object (tinted red):

These differences are consistent across the skull specimens of Cod and Pollack that I’ve managed to find. The Cod has notch in the upper leading edge of the hyomandibular, unlike the Pollack, which has a more obtuse smooth line along the leading edge. The Cod also has a notch in the trailing lower edge of the opercular, that is just seen as a slight concavity in the Pollack.

I’d be interested to hear what you think about these suggested features!

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

Happy Friday everybody! This week I have a genuine mystery object to solve from the Dead Zoo:

This specimen has no location information and only a generic name associated with it – the only other information is that it was collected by Major St. Leger Moore. That might help. Or it might not. Let’s see what you manage to come up with!

Friday mystery object #403

This week’s mystery object is one I’ve been sitting on for about seven years and I’ve held off posting it because I think it might not be much of a challenge for some of you. However, it’s an incredibly cool object and I think it’s time to share it:

If you know what this is, please keep your answers nice and cryptic so the people who don’t recognise it can enjoy the challenge. Have fun!

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

Friday has rolled around again, with startling alacrity.

At the Dead Zoo it’s been another busy week of decanting, with our whale skull being crated up and ready to roll:

All the decant work plus post-Christmas catching-up activity hasn’t left me much time to hunt down mystery objects, but I had this cutie in my office and I thought it might be a nice little challenge:

Any idea what it might be?

As always, you leave your questions, thoughts and suggestions in the comments below. Have fun!

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!