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!

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