Friday mystery object #417 answer

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

Pretty much everyone recognised it as a marsupial, thanks to the palatal vacuities and inflected angular of the mandible (as Allen Hazen alluded to).

The size, general shape of the skull and tooth shape narrows down possible species very quickly, as it’s quite large (at around 17cm) and quite kangeroo-shaped. That leaves the likely options as Eastern-grey, Western-grey or Red kangaroos.

Red Kangaroo skulls tend to average around 205mm long, Greys tend to average in the region of 145mm, so this falls between the two – either a small Red or a large Grey.

The sutures of the skull seem well-fused and there are quite robust muscle scars, suggesting a well-developed adult animal. For me this hints that it would probably be in the large end of the size range of its species, rather than at the small end of the size range – hinting at it being a Grey.

Another feature that hints at Grey Kangaroo is the crown of the third upper incisor, which in Red Kangaroos tends to be slightly broader than it is long, whereas in Greys it tends to be longer than wide.

Unfortunately, I’ve so far failed to find good enough verified images or specimens of Western Grey Kangaroo skulls to differentiate from the Eastern Grey.

I do know that this mystery specimen is identified as an Eastern Grey Macropus giganteus Shaw, 1790, but I am also aware that the taxonomy of these animals has been complex and confusing, especially since their ranges overlap so I don’t fully trust that identification. Sometimes a dose of scepticism is important when dealing with historic collections, so I think I’ll just leave it there after the tough week I’ve had.

Friday mystery object #416 answer

Last week I gave you an anatomical specimen to have a go at identifying:

It proved a popular object, perhaps unsurprisingly given its unusual condition. This becomes a bit clearer when seen the specimen is seen from the back:

The fact that it’s conjoined at the head and chest is fairly obvious, but what kind of animal is it?

This is where the discussion got interesting, with a variety of different aspects of the morphology being discussed, ranging from number of vertebrae to shape of the rostrum (or nose if you prefer). Generally the conversation went back and forth between dog and cat (although sloth also came up).

For me, a handy place to check when trying to differentiate juvenile cats and dogs is the unguals – the tips of the toes. The claws of cats and dogs are quite different. If you look more closely at the image above, you can see that the unguals in this animal are deep-bellied at the base and steeply curved:

This claw shape is functionally well adapted to climbing and the broad base relates to a retractile mechanism – something very feline. Here’s an example from a much bigger felid – a Tiger.

So this is the skeleton of a conjoined kitten. Well done to Chris Jarvis, who was the first to comment and he correctly spotted the feline nature of this specimen.

Friday mystery object #415 answer

Last week I gave you this Blaschka glass model of a marine invertebrate to have a go at identifying:

It was a bit of a mean one, since it’s from a very poorly known group of animals – and I mean that in more than one way. The taxonomic group is poorly known and the model represents a group of animals, not just a single individual.

So while this looks a bit like a jellyfish, it’s actually a siphonophore, which is a type of colonial organism that has discrete cloned zooids which fulfil specialised functions, similar to organs that cooperative to create a metaorganism.

Generally in siphonophores, these zooids are arranged on a stem in an organised pattern, with either two or three main zones of specialised zooids, depending on the taxonomic Suborder.

The zooid zone common to all siphonophores is the siphosome made up of feeding zooids with stinging cells, reproductive zooids and sometimes zooids with defensive functions. The two other zooid zones are the nectosome, which is comprised of zooids that act like tiny jet engines for swimming and the pneumatophore, which is a gas-filled zooid at the top of the stalk that acts as a float:

The presence or absence of particular zones is indicative of the particular Suborder of siphonophore, where the Physonectae have all three zones, the Cystonectae lack the swimming zooid zone and the Calycophorae lack the float.

I’m telling you all of this because it helps in narrowing down the mystery object. As you can see, there is no single zooid at the top acting as a float, so it must be one of the Calycophorae.

Within the Calycophorae most families only have one or two swimming bells and although the nectosome in the mystery object is not quite up to the Blaschka’s usual level of detail, it clearly contains more than two zooids, which is a feature of the Hippopodiidae.

The Hippopodiidae only contains two genera, Vogtia and Hippopodius and the two can be distinguished by the shape of the nectophores – in Vogtia they’re pentagonal whereas in Hippopodius they’re a more simple crescent shape – as we see here.

Back when the Blaschkas were making their models, there were a few species included in the genus Hippopodius, but they only made one that’s mentioned in their catalogues:

“209. Hippopodius gleba, Leuckart (Hippopoda lutea, Qu. & G.)”.

These days all the various species have been synonymised to just one РHippopodius hippopus (Forssk̴l, 1776).

So well done to everyone who recognised that this was a siphonophore, even better if you spotted it was one of the Calycophorae and bravo if you got the genus (and therefore species).

Next week I plan to have a change from Blaschkas, much to everyone’s relief I’m sure 😉

Friday mystery object #415

This week I was hoping to give you some skulls to try identifying from the Royal College of Surgeons in Ireland, but unfortunately all my well-laid plans were scuppered and I was unable to get away from the Dead Zoo. As a result I’ll afraid that I have yet another one of those ghastly Blaschka glass models for you to have a go at identifying:

The usual Blaschka rules apply – full points for the name and order catalogue number used by the Blaschkas (the catalogue can be found here) and bonus points for the current name for whatever this model depicts (if the taxonomy has changed).

I hope you enjoy this week’s challenge!

Friday mystery object #414 answer

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

It seems as though you’ve all managed to get your eye in with the Blaschka identifications, since there was a flurry of correct answers both in the comments on the blog and on Twitter.

Those exposed gills immediately let us know that this is a nudibranch sea slug. From there I thought it might prove more of a challenge, but by looking at the physical characteristics shown it quickly became obvious what we were looking at – at least when there is a handy catalogue to look at and provide clues.

In this case, the clue lay in the scientific name of the species: Polycera quadrilineata (O. F. Müller, 1776). As you might expect, it has many (poly-) horns (-cera) and four (quadri-) lines (-lineata), making the name helpfully descriptive. At least in this instance. The problem is that the name could be much less helpful if this model depicted the same species with a different morphotype.

In fact, it seems that there has been a separate species of Polycera hiding in plain sight until very recently. The wide variety of different colours and patterns associated with P. quadrilineata has meant that the new species Polycera norvegica Sørensen, Rauch, Pola & Malaquias, 2020 was only identified in last year, because it was lumped together with its more lineated cousin (that often lacks its stripes).

Separating these species relies on finer details than just overall appearance of course – the team that identified this cryptic critter did so on the basis of detailed morphological and genetic work that you can read about here.

It does help illustrate an ongoing problem faced when dealing with historic collections though. There have been a lot of species that have been similarly split, especially since molecular methods have become so much more accessibble. When working with old specimens it’s not unusual for these little bits of scientific progress to have been missed.

I’ve grumbled about this before, but it is a particular problem that can make dealing with Blaschkas so much more complicated. Fortunately there has been some work done on trying to match some of the more distinctly fishy taxonomy used by the Blaschkas to more modern versions, but there are still some impossible examples where the Blaschkas reproduced something from a source that had little bearing on real species. I promise I won’t set one of those as a mystery object.

Probably.

Friday mystery object #414

The last mystery object I gave you was one of the Dead Zoo’s Blaschka glass models and it proved to be a nice challenge. So here’s another one of them that’s become dissociated from its data in the mists of time for you investigate:

Same rules as last time – let’s see if you can figure out the species and the catalogue number (here’s a link to the catalogue to help with that). Have fun!

Friday mystery object #413 answer

Last week I gave you this cute little Blaschka glass model of a squid to have a go at identifying:

Now that isn’t as easy as it might seem, since the Blaschkas spent over 20 years in their Dresden workshops making models of marine invertebrates, which included 50 different species of cephalopod. Moreover, many of these models did not survive the last 150 or so years, making comparable examples quite hard to find. On top of that, the taxonomy of the animals that the Blaschkas created models for has changed significantly in that time, meaning that everything gets very confusing when even trying to refer to particular models.

As such, when we’re working with Blaschka models we find it useful to refer to the order catalogue numbers established by H.A. Ward in 1878. Of course, that means we also have to rely on the old taxonomy used at the time and we still have problems when referrencing specimens made before 1878, since the Ward numbers hadn’t been established – plus the models offered in the various iterations of the catalogues changed to meet demand.

Much of that demand came from museums and universities all over the world, with the delicate lampworked models being mail ordered. The only way in which the person ordering could know what they were likely to receive in the post was to check out the scientific engravings of the animals that the Blaschkas faithfully reproduced in three dimensions. Usually there would be just a few references for any particular taxonomic group, so it probably wasn’t too difficult to get an idea of what to expect.

In the case of the squids, most were based on illustrations from Mollusques méditerranéens observés, décrits, figurés et chromolithographiés d’après le vivant – 1re partie: Céphalopodes de la Méditerranée by Jean-Baptiste Vérany, 1851, so that provides a good place to start looking.

It takes a while to get your eye in, but there are various details in each of the specimens that makes them more or less likely to be the illustration the model was based on. For this one there are a few that have similar proportions and colouring, but this also has what I like to refer to as the “double chin” (or perhaps “double neck” is more accurate). This feature is absent from most of the illustrations and therefore from most of the Blaschka squid models. Except this one.

Trawling through the Vérany book offers up a very good illustration providing the base for this model, the comparison spoiled only by photography done using my phone, which has a propensity for distorting the extremities of small 3D objects. Here’s what I think we’re dealing with:

This is what Vérany (and the Blaschkas) called Enoploteuthis Owenii and what is now known as the Eye-flash Squid, Midwater Squid or Abralia veranyi (Rüppell, 1844).

In the Ward versions of the Blaschka catalogue from 1878 and 1888 this model is listed under the number 554. So I offer my hearty congratulations to Adam Yates, who got both the species and the number. I hope you enjoyed this wander into the world of Blaschka models – I have other examples that I’ve identified recently, so I might just challenge you with another again soon…

Friday mystery object #413

This week I’ve been packing some of the Dead Zoo’s beautiful Blaschka glass models, that were moved during our decant and have been sitting in my office waiting to be dealt with:

Most of the Blaschka models we have are well identified and many even have the number that they were given for ordering in the Catalogue of Glass Models of Invertebrate Animals, Ward’s Natural Science Establishment, by H. A. Ward, Rochester, N.Y., 1878.

However, as is sometimes the case with old collections, there has been a degree of dissociation of information from the specimens and one or two of our models have lost their data. This little squid is one such specimen.

I managed to track down the modern accepted name for this specimen, which is very different to the name used by the Blaschka’s when they made and sold this model. With that original name I was even able to figure out the order number from the Ward catalogue. I enjoyed the detective work and I hope you do too!

Let’s see if you all come to the same conclusion about this specimen as I did. I’ve added a couple of extra images below to help you in your quest. Have fun!

Friday mystery object #412 answer

Last week I gave you this rather nice skull to identify:

I was hoping that it would catch some of you out, since at first glance it looks like the skull of some kind of canid. I thought I had caught out Joe Vans, but then he noticed one of the features that sets this skull apart from dog skulls – the pinched-in section in the mid-muzzle area. Then everyone started piling in with their observations and my hopes of being tricksy were fully dashed.

This is of course the skull of that paragon of convergent evolution, the Thylacine (AKA the Tasmanian Wolf or Tiger) Thylacinus cynocephalus (Harris, 1808).

I’ve written fairly extensively about convergent evolution between Thylacines and canids before, when I worked at the Grant Museum of Zoology, so I won’t go into huge detail here, but I will give you an annotated image showing some of the features to look for that help distinguish these marsupial carnivores from their placental dopplegangers:

A= 8 incisors vs 6 in canids
B= Lacrimal duct on outside of orbit
C= Inwardly deflected angular process
D= “Pinched” midsection of rostrum
E= Palatal vacuities

These physical differences between the Thylacine and the Eutherian canids are features common to many marsupials and they act as reminders that evolution is limited by what it has to work with. At the most fundamental level that means DNA.

In recent years the methods for successfully extracting and sequencing DNA from museum specimens has moved on in leaps and bounds. In 2018 these advances allowed the Thylacine’s genome to be assembled, allowing comparison with their morphologically similar, but taxonomically distant counterparts.

The team that did this went looking for similarities between protein coding genes in the different lineages at first, to understand what was driving the morphological convergence – but it seems that they were looking in the wrong place.

When they looked more closely, it was actually in the cis-regulatory elements (the non-coding DNA that used to be considered “junk”, but which is now recognised as playing a vital role in regulating development) that genetic convergence was seen. It turns out that these elements were also driving convergence in brain development between Thylacines and canids.

It seems that protein coding genes are quite stable – if they mutate they usually stop working properly, so the mutation often doesn’t persist. But mutations in cis-regulatory elements can change gene expression with less risk of catastrophic consequences. Unsurprisingly that means they are increasingly being seen as the main drivers in evolutionary adaptation. If you’re interested in finding out more about this fascinating research, a pdf of the 2019 paper on Thylacine/canid genetic convergence by Feigin, Newton & Pask can be accessed here.

I hope you enjoyed this short trip down the road of convergent evolution, with a hat-tip to the genetic drivers involved.

Friday mystery object #412

After last week’s foray into insects, I have a nice chunky vertebrate skull to for you to have a go at identifying:

Any idea what this might be from? I have a feeling this may be way too easy for some of you, so let’s keep the answers cryptic or perhaps poetic, so everyone gets a chance to figure it out for themselves. Have fun!

Friday mystery object #411 answer

Last week I gave you this (somewhat dusty) mystery object to try your hand at identifying:

I know that insects aren’t a frequent occurence on the blog, so this was a bit of an unfamiliar one for many of the regular Zygoma commenters. Of course, that didn’t prevent some astute observations.

Chris Jarvis immediately spotted that this is a wood wasp or sawfly, while palfreyman1414 flagged that it looks more like a fly (barring the long ovipositor). That’s because wood wasps, despite being members of the Hymenoptera, lack that characteristic wasp-waist that makes the Apocrita (the hymenopteran Suborder containing wasps, bees and ants) so distinctive.

Not a fly, but not really a wasp either

The Symphyta is the Suborder containing the sawflies and there are thousands of different species. However, narrowing it down wasn’t really that hard, since sawflies specialise in using their ovipositor to lay eggs in the stem of quite specific host plants and the only sawflies in this size range are in the family Siricidae, which are the ones that pick on trees (which is pretty interesting, since they form a symbiotic relationship with wood-digesting fungi in order to feed on wood as larvae).

Quite a big bug*

Of course, being insects, there are still around 150 to choose from, but between ruling out taxa that have adopted Batesian mimicry and those that are a very different size or shape, it becomes easier to narrow down the possible contenders – especially when you consider that this one turned up in Dublin, Ireland (although as pests of wood they can emerge from pine timbers a long way away from their point of origin – this one probably got into the Dead Zoo in some of the timber being used for our big decant project). The best fit for this specimen lies in the Genus Sirex.

When tryingto to distinguish between members of Sirex it’s important to pay attention to colour details of the legs and antennae. In this case it has red legs and black-and-red antennae. If you spend a while checking through the very helpful Sawfly GenUS resource you’ll find that the best fit for the mystery specimen is a female Sirex juvencus (Linnaeus, 1758).

Of course, the entomologists out there managed to figure all this out without any problems, both on Twitter and in the comments.

So well done to Jaswinder and Russell Stebbings for getting a species level identification – I would say that you got it right, but since I’m not an entomologist I think I should just be pleased that your more informed opinions happen to support my best guess. Thanks!

Stay tuned for another mystery object next Friday. Have a great weekend everybody!

*not a Bug – the True Bugs are Hemiptera and have nothing to do with this.

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