Friday mystery object #505 answer

Last week I shared this specimen from the collections of the Dead Zoo, as it’s a good example of the type of specimen that will often turn up for identification:

If you didn’t recognise it, this is the braincase of a seal.

It’s not usual for seal skulls to be found in sections like this for a few reasons. One is that marine mammals tend to have quite open sutures in their skulls, presumably to help prevent issues with pressure during diving. Another is that young animals (with unfused skulls) will often be the ones that succumb to the rigours of nature. Finally, beaches are high energy environments, so skulls will often be rolled and broken up by wave action.

Knowing it’s a seal is useful, but there are over 30 species to choose between. However, Adam Yates spotted some useful information written on the specimen:

‘It looks like “Yellow Slrank 20/9/92” ???? I’m guessing a location and date, but Slrank? WTF is that?

Got it! Yellow Strand. It is a beach in Ireland.’ 

This really helps, since there are only a couple of species that are likely to be found in Ireland – the Grey Seal and the Harbour Seal.

It’s about the right size for a Harbour Seal, but the shape isn’t quite right. In particular, the frontals (that pair of bones that forms the skinny section that’s sticking out) aren’t skinny enough. There’s also a hint of muscle scars and unfused frontal-parietal sutures that suggest that the animal may be juvenile.

If that is the case (and I think it is), then I think this is most likely the skull of a young Grey Seal Halichoerus grypus (O. Fabricius, 1791). This was Adam Yate’s suggestion, supported by Kat Edmonson, so well done to them for picking up on that detail.

I hope you enjoyed that challenge – more to come next week!

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