Friday mystery object #359 answer

Last week I gave you this fishy mystery to have a go at solving:

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I find fish a bit tricky, simply because there are so many different species out there – 33,100 described so far and rising. That’s more than all other vertebrates combined, so it’s not surprising that they can be a challenge.

However, this cartoonish looking little fish has some quite distinctive features that help narrow down the identification. There’s the duck-face with a couple of little barbels between its eyes and the clumping of the fins to the tail end. It also has a nice colour, but as I regularly say, that’s seldom a very reliable guide.

Generally, fish shaped like this don’t swim fast, they don’t lie flat on the sea bed and they don’t wriggle through weeds. This is the shape of a clinging fish – the kind that hold fast to a surface and let the world wash over them.

There are a good fish that do this, but I did say that this one is from Ireland, which helps narrow it down even more – enough for Chris to identify it correctly. This is a Cornish Sucker Lepadogaster purpurea (Bonnaterre, 1788). These weird little fish are pretty awesome. They cling to rocks along the shore with a suction cup made from their fused pelvic fins and they can change colour to blend into the rocks they attach to. Partly this will be for camouflage to avoid predators, but it will also be to help them ambush the smaller fish and crustaceans that they feed on.

One small issue for me is that the name on the label for this specimen is Lepadogaster lepadogaster (Bonnaterre, 1788). The taxonomy of this genus was reassessed in 2002 and the northern population of Lepadogaster (including those from the UK and Ireland) was found to be distinct from the more southerly distributed population. So once again, I need to update a label because advances in taxonomy have messed up our 100+ year old information. That’s the trouble with science – it keeps finding out new stuff.

Friday mystery object #358 answer

Last week I gave you this skull from customs to have a go at identifying:

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The long horns rising in line with the plane of the face are a distinctive feature of the genus Oryx, which most of you spotted straight-off.

However, after that it gets a bit more tricky, not least because there are several species of Oryx and within the species there are different subspecies and populations from different parts of the African continent.

The first species that’s easy to rule out is the Scimitar Oryx, O. dammah since they have strongly curved horns which don’t diverge as much as this specimen. This species is currently extinct in the wild and individuals only survive in captivity.

 

Scimitar Oryx in Werribee Open Range Zoo in Victoria, Australia. Image by Waddey, 2009

 

Next up is the Arabian Oryx O. leucoryx which used to be extinct in the wild, but which is one of the few species to have become reestablished in the wild by captive breeding and release programmes. This is the smallest Oryx and the mystery specimen’s horns are way too long to be from this species.

Arabian Oryx in the Dubai Desert Conservation Area. Image by Sharp Photography, 2014 

Getting to the more likely species, there’s the East African Oryxwhich either has a couple of subspecies or is two different species – the Common Beisa O. beisa, which is endangered and the Fringe-eared Oryx O. callotis, which is threatened. The other possibility is that it’s a Gemsbok O. gazella, which is still doing well in the wild.

Common Beisa. Image by Steve Garvie, 2010

Fringe-eared Oryx. Image by Riaan Marais, 2009

Gemsbok. Image by Sharp Photography, 2018

As you’ve probably worked out, part of why customs are interested in knowing which species this specimen belongs to is knowing what level of protection it has under CITES, should they need to pursue a prosecution. Regardless, the specimen was seized because it wasn’t properly prepared and it entered Ireland without the appropriate information.

Of course, differentiating between the Gemsbok, Beisa and Fringe-eared Oryx using only the skull is tricky (and even harder if you only have photos).

Fortunately, there is literature that can help, with measurement ranges for certain features, like horn length, distance between horn tips and number of rings on the horn. Of course, these are only indicative, but they offer a guide to most likely species. Ungulate Taxonomy by Groves & Grubb, 2011 has a handy table of these, which I used to narrow down the options to just one – a population of Gemsbok Oryx gazella (Linnaeus, 1758) from the Nata River in the northeastern region of Botswana.

Of course, DNA sampling can offer a more certain diagnosis these days, but only if there is a good quality reference sequence to compare against and it assumes there is the equipment and expertise available to do the sampling and analysis. This is why identification from morphology can still play an important role in managing wildlife crime.

Friday mystery object #358

Another Friday, another mystery object. This week I’m going back to my favourite subject – skulls. This particular specimen has been brought in to the Dead Zoo for identification by customs and although I’ve narrowed it down, I’m still not 100% sure of the species just yet:

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It’s a fairly straightforward genus for anybody who knows their ungulates, so cryptic clues are appreciated. However, the species is harder to work out, so bonus points for detail. Have fun!

 Friday mystery object #357 answer

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

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Despite it having a passing resemblance to a Xenomorph Facehugger, it’s a real animal from planet Earth, although not from earthy bit. As many of you recognised, this is one of the pycnogonids or sea spiders.

This group of arthropods is placed in the Chelicerata along with spiders and horseshoe crabs on the basis of their morphology, although genetics suggest that their roots may lie nearer the base of the arthropod family tree.

You’re unlikely to encounter one of these giants since they live in the deep sea, but smaller types (usually only around a 1cm long) are found on most rocky shores, where they feed on bryozoans and hydroids.

This one is from around Franz Josef Land, an archipelago in the Russian Arctic. Several people dropped hints to the genus – in particular Hilary, Chris, Wouter van Gestel, Daniel Calleri & Dan Jones, but Andrew Taylor just came out with it: Colossendeis. The clue there is really in the size.

However, this is a tricky one to narrow down to species. There is an online key to the pycnogonids but unfortunately it’s not totally comprehensive. That said, this species is represented in the key and it’s actually quite distinctive because of its huge proboscis (N.B. the head points upwards in this specimen), quite compact almost disc-shaped body and lack of eyes.

These characteristics match the description for Colossendeis proboscidea (Sabine, 1824), which is more commonly known as the Blind Pycnogonid. Now I want to find out who collected this specimen and donated it to the Dead Zoo back in 1899.

There weren’t too many Arctic expeditions prior to 1900 and this specimen is almost certainly from one of those few. It could possibly be from the Austro-Hungarian North Pole expedition. In 1872 they discovered Franz Josef Land and in 1874 named one of the islands in the archipelago McClintock Island after the notable Irish Arctic explorer Francis Leopold McClintock. It’s not impossible that they would have sent specimens to McClintock or the Museum in Ireland, so it may be time to hit the books to see if I can find any more information!