Friday mystery object #303 answer

Last week I gave you this mysterious bit of bone from the Thames to have a go at identifying:

mystery303b

A few ideas were put forward, but DrewM was spot on with the suggestion:

I think it’s the synsacrum of a bird, without the ilia fused – the foramina are for spinal nerves.

A synsacrum is a fused section of vertebrae including the sacrum (which is where the pelvis attaches to the spine). General opinion quickly agreed with that suggestion, but the taxonomic group that the synsacrum belongs to remained unguessed.

That is perhaps unsurprising, since it’s hard to find good comparative images of bird synsacra, especially with the hips and lateral (or side) bits knocked off and worn down.

chicken synsacrum

A Chicken synsacrum showing the section preserved in the mystery object

I had a go at looking through some of the comparative bird osteology collections at the Dead Zoo to get a feel for birds with a similar synsacral morphology.

The usual suspect for a bird bone found in the Thames (for me at least) is Chicken, since they’re so closely associated with humans and a lot of the bones washed up on the banks of the Thames are from butchery and food waste. The size was about right, but the vertebral centra (the middle bits) of the Chicken synsacrum become more narrow in the hip-line than in the mystery specimen.

Next I looked at ducks, whose centra taper more in the direction of the tail, then grebes whose whole synsacrum is more narrow overall:

grebe synsacrum

Synsacrum of a Great Crested Grebe

Eventually I made it to the gulls who seem to be a much better fit in terms of shape and the Herring Gull Larus argentatus Pontoppidan, 1763 was a good fit for size:

herring gull synsacrum

Herring Gull synsacrum

Now this doesn’t mean to say that the mystery object is certainly from a Herring Gull. I would want to have the object in my hand and comparative material available from several specimens to check the identification before being sure, but on the basis of the images that Keith Dunmall kindly provided, I think we’re in the right ball park.

More mysteries next week!

Friday mystery object #303

This week I have a real mystery object for you to try your hand at identifying. It’s from the River Thames and it was found by a strandline archaeologist who shared it with Keith Dunmall (who is a Youth Engagement Manager at @WaterAidUK) during a planning meeting for @Thamestidefest.

Keith shared it on Twitter looking for an identification, and he kindly sent me some extra pics:

mystery303amystery303bmystery303c

Do you have any idea what this might be?

No need for cryptic clues, I think this one may be tricky enough to be enough of a challenge as it is!

Have fun!

Friday mystery object #302 answer

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

mystery302

Eggs can be tricky, since they are largely similar in shape and, since egg collecting was banned many years ago, there are few modern resources for identification.

However, you can pick up clues by thinking about colour and pattern and working out what advantage it may have. So you might expect a brightly coloured egg to be laid in a well disguised and deep nest, where it’s unlikely to be spotted except by the parent, whereas a yellowy speckled egg is more likely to be camouflaged if laid in a fairly open, sandy environment.

So this egg was probably laid somewhere near the sea, which means it’s probably from a charadriiform bird (those are the shorebirds).

Now there are a lot of shorebirds, but this egg is pretty big and it lacks the strongly conical shape you’d expect from a cliff-nester like a Guillemot (the shape means it rolls in tight circle, making it less likely to be blown or knocked off a cliff). That actually narrows it down to a handful of birds that makes comparison easier. Curlew eggs, for example, are a similar size, but they tend to be more grey and have larger blotches, plus they’re a bit less elongated.

This particular egg has the shape and colour of a gull egg and large size means it’s almost certainly the egg of a Greater Black-backed Gull Larus marinus Linnaeus, 1758.

I would say more, but at the moment I’m at the natural history highlight of the year – the NatSCA conference. Here’s the Twitter feed in case you’re interested in the discussion:

Friday mystery object #301 answer

Last week I gave you this mystery tooth to have a go at identifying:

mystery301bmystery301a

There were a variety of answers, but the first few took this as a worn canine tooth, presumably due to the respectable size and robustness. However, consensus shifted to this being an incisor, meaning it would have to be from a large animal – which is spot on. Moreover, it’s a large animal that was once resident in Ireland.

After that there were a variety of ideas brought up, from all manner of beasts including Sheep, Badger (or perhaps Pine Marten since a cryptic M.m. from the Irish fauna could be either Meles meles or Martes martes), Cave Bear, Coyote, Wolf and even Human. There was one just correct identification however, by Tony Morgan who recognised it as a Hyaena incisor.

It is in fact the lower left third incisor (or i3) of Crocuta crocuta (Erxleben, 1777) – the tooth you can see in this (very gnarly) Hyaena mandible, although it’s much less worn:

Hyena mandible

Hyaenas have an incredibly thick enamel layer on their teeth which creates a distinct neck on the incisor where it stops, which is further defined by the root of the tooth bulging laterally below – presumably to help deal with the forces of prey capture and perhaps the Hyaena’s impressive bite strength.

mystery70

The robust skull of a specialist bone-crusher

You probably don’t think of Hyaenas as being native to Ireland, but until 39,000 or so years ago they ranged right across Eurasia, including those parts of Europe which were to be cut off by changing sea levels to form Ireland and Britain.

It’s strange to imagine a species normally associated with the African savanna strolling around the Emerald Isle, but it’s worth remembering that the world is a constantly changing place and wildlife moves around to cope as the environment alters. Borders and boundaries are very human concepts and other species only pay attention when you have a genuine barrier, like an ocean, a mountain range or (if you’re a Dormouse) a break in the tree canopy.

That’s one of the problems with current climate change compared to past climate variations. The speed of change is so great that some species don’t have time to move into new habitats and there are fewer suitable habitats available, because humans have cleared them for farming or building. Meanwhile, some other species can find suitable habitats and are able to move – but they will then often be considered an invasive pest. Now  the chances of Hyaenas returning to Ireland are pretty slim, but if they did I expect most people wouldn’t be too pleased, although you never know…

Kevin Richardson kisses hyena. Image by Kevin Richardson, 2007

Kevin Richardson kisses hyena. Image by Kevin Richardson, 2007

Friday mystery object #300 answer

Last Friday I gave you this new acquisition to have a go at identifying:

mystery300

When it arrived on my desk in an decorative box, with bundles of bone wrapped in blue tissue and tied with gold ribbon, it had a small label saying:

Skeleton of Mongoose, Africa.

Now, I know that having the continent would have been of help for the identification, but I didn’t want my 300th challenge to be too easy.

So how was that initial identification of Mongoose? It was certainly up there in the first of the comments, with Ric Morris (expert on British mammal bones, whose book I am eagerly awaiting) providing a beautifully crafted suggestion. Unfortunately it isn’t right, as the mongooses mongeese Herpestidae* tend to have a better developed post-orbital process (that’s the pointy bit on top of the skull, behind where the eye would be) and a corresponding process on the zygomatic (that’s the cheekbone), with the two sometimes meeting to form a post-orbital bar. They also tend to have more robust teeth.

Another (very) cryptic clue came from jennifermacaire who suggested that it was a civet (which can either be a type of viverrid carnivore or a French game stew). This suggestion was supported by henstridgesj and it’s closer than the mongoose suggestion, as the specimen is indeed from a species in the Viverridae. This was noticed by herpderpatologist who provided a handy tip for spotting the difference between mustelids and viverrids:

The split auditory bulla is a clue! It’s something I associate with viverridae;…

If we know that this is a viverrid, it narrows it down to one of  just 38 species…  which is still quite a lot. But by trawling through the images of viverrid specimens on the University of Michigan Animal Diversity Web it becomes easier to start narrowing down the likely group within the Family.

In this case it led me to the genets.

There are quite a few genets, with the Subfamily Genettinae containing in the region of 16 species. Distinguishing between them isn’t entirely simple, as they all look pretty much alike, but there is an excellent French resource that has detailed anatomical characters and images of specimens to help distinguish between genet species.

Working through this I found that the two best options were the Common Genet and the Cape Genet and distinguishing between them is not simple. I’m leaning toward the Cape Genet (or Large-spotted Genet) Genetta tigrina (Schreber, 1776), based on the spacing between the tympanic bullae (the bulbous bones under the skull that house the ear bones), the reduced lingual cusp on the P3 (that’s the tiny bit that sticks out towards where the tongue would be on the upper third premolar) the form of the upper first premolar (P1) and the shape of the maxillary-palatine suture (that’s the junction between the bone of the palate and the part of the upper jaw that supports all the teeth except the incisors).

That’s quite a lot to take in, but by getting your eye in and scanning through images it’s surprising how quickly you can narrow down options by rejecting images where you can see clear differences in the tympanic bulla configuration or cusp pattern on the P3 to leave a couple that need more careful consideration.

And just for the sheer squee of it, here’s what a Genet looks like when it’s alive:

Common Genet, by Peter 2011

Common Genet, by Peter 2011

I hope you enjoyed the challenge of the 300th mystery object!

 

*N.B. the plural of mongoose is “mongooses”.