Friday mystery object #542 answer

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

It’s not the easiest of tasks, as there are quite a lot of birds in this general size range and with this general shape of skull, so the overall outline from the top only helps narrow things down a little. It is worth noting that general proportions all suggest some kind of Passeriform.

The exact length of this specimen is 49mm, but as with all species, there is a bit of variation depending on subspecies, age, sex, quality of diet and other environmental factors. I suspect this one is a little on the small side for the species.

The side view offers another perspective on the bill morphology, which is looks quite generalist, perhaps a little on the gracile side, but not overly skinny. Given the size that puts me (and many who left a comment) in mind of something in the Thrush family.

It’s also worth noting that the bill sheath, while not very apparent, is still present (if it wasn’t you’d see small holes along the side of the bill, which are the blood vessels that supply the tissues that secrete the keratin of the bill sheath). This is a big clue, as the bill sheath is yellow.

For me that immediately put in my mind a very specific type of Thrush – the male Common Blackbird Turdus merula Linnaeus, 1758.

This can be checked with reference to the excellent Skullsite resource, which provides a fantastic range of bird skulls with images from several different angles. Take a look at the underside of this specimen:

The posterior region of the palatine bones have quite a distinctive shape – flared and with a broad shallow notch at the posteriormost margin. If you compare this to other skulls in the genus Turdus, you’ll notice that the notch is almost absent in the Redwing, it has a much sharper outer angle in the Songthrush, it’s a lot deeper in the American Robin, it’s deeper and sharper in the Fieldfare, and so on. The important thing is that the palatine of the Blackbird on the Skullsite is still consistent with that of the mystery object.

While this feature takes a while to get familiar with, it can be quite helpful when narrowing down similar skulls like these. I hope that pointer proves useful!

Finally, I offer up congratulations to Adam Yates who not only got the correct identification, he also left a great cryptic clue to share that information. Bravo!

Friday mystery object #541 answer

Last week I gave you this leggy mystery object to identify:

As I suspected, it wasn’t a difficult challenge in terms of working out the species, since it is one of the most common examples of its type. To make it a bit more interesting I also asked for you to keep the answer cryptic for extra points.

Chris Jarvis was first to the party referencing “stone” – part of the common name of this species. Adam Yates gained some extra points by cleverly working in a reference to the species name “forficate”, and Joe Vans managed to work a rhyme into his correct response.

This is, of course, a Stone (or Garden, or Brown) Centipede Lithobius forficatus (Linnaeus, 1758). It’s a very widespread species, ocurring across Europe as its natural range, but also now widespread in North America – even occurring on the Hawaiian islands and with records from Colombia.

These centipedes live in leaf litter and hunt small invertebrates with their venomous front legs (which are called forcipules).

These centipedes can actually be quite difficult to definitively confirm the identification of, as they share a lot of similarities with other Lithobius species, such as the larger Lithobius pilicornis Newport, 1844, so a proper key is really needed (the British Myriapod and Isopod Group have some very useful resources) and specimens are essential for any surveying work that takes place, to allow checking of detailed features under a microscope – such as the forcipular teeth.

This is why specimens are an important validation resource for confirming species identifications, and appropriate lodging of these specimens in collections is important, to allow observations to be checked and confirmed.

Thanks to everyone for playing – let’s see what mystery object I’ll stumble across for next Friday’s challenge. Have a lovely weekend!

Friday mystery object #541

This week I have an interesting invertebrate for you to identify:

I suspect this won’t be a difficult species for some of you, so please keep your answers cryptic – with bonus points for creativity. I look forward to hearing your musings!

Friday mystery object #540 answer

Last week I presented this mystery object for your identification delectation:

While this is such a heavily processed piece of skin, with most of the diagnostic features removed, an additional close-up image provided a clue:

People in the comments section and on Bluesky recognised that this is the skin of a member of the Batomorphi (AKA the Rays). While there were some differences in opinion on the species, there is one term that came up several times in several ways, but in the words of Chris Jarvis:

Much to my chagrin I think I might know what this is?

This is of course a reference to the material shagreen, which is a type of leather (often dyed green) with rough dentine inclusions that are polished to create “pearls” embedded throughout.

Shagreen used on a Japanese personal dining set, featured in Mystery Object #25 (all the way back in 2010)

There are several species of Ray – and indeed some sharks – with skin used to make shagreen. One is called the Shagreen Ray, but I suspect that this is not an example of that species, despite it occurring in Ireland (there’s a very helpful guide to the Skates and Rays of Ireland if you’re interested).

I think this mystery object might be a Cowtail Stingray Pastinachus sephen (Forsskål, 1775), since that species has been extensively harvested to supply shagreen in the past, and the object is lacking the distinctive denticle patterns that can be used to help distinguish between the Shagreen Ray and other similar species.

It could of course be another species, and if anyone knows of a definitive set of features visible on this specimen, I would love to know what they are. So I would like to congratuate everyone who mentioned rays and shagreen!