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DISPLAYING POSTS TAGGED: identifications (3)

Fossilised Champignons

Author
by Siobhan
Publish date
15 September 2013
Comments
Comments (1)

Remember The X-Files? If you were a fan, you fell into one of two camps – you either liked the mythology arcs, or the Monster-of-the-Week episodes. I fell firmly into the latter camp. I liked one-off weirdness, lacking the attention span for conspiracy narratives. It is in this spirit that I present to you a short episode of "What on earth is THAT?!" from the Discovery Centre.

At the beginning of winter this year, a woman came into the Melbourne centre with some "mysterious objects". We get a lot of mystery items here, and they are normally fairly easy to identify – pieces of manufacturing slag, cicada cases, random pieces of urban archaeology that work their way up from old rubbish pits.

As she removed them from her bag, she said, "they look like fossilised champignons." An odd description, but entirely accurate. The items she unwrapped did indeed look like small mushrooms. They weren't fossils, as they were obviously made of a chalky substance; soft enough to flake and leave a slight powdery residue on one's fingertips. Our visitor said she had discovered them in the mud on the shores of a freshwater pond on Kangaroo Island, and mentioned, in an offhand manner, that they were amongst some crayfish carcasses, and perhaps they had something to do with local platypus? I was stumped. My colleague Wayne, a chap with a palaeontological background, was equally stumped.

Crayfish gastroliths Crayfish gastroliths, brought in to the Discovery Centre for identification.
Image: Siobhan Motherway
Source: Museum Victoria
 

Found in platypus territory, and made of chalky material? We did some preliminary research: were they dehydrated platypus eggs? Some weird botanical thing? A fungus? Yes, I did google "fossilised champignons". Getting nowhere, we turned to our various departmental experts in Mammalogy, Marine Invertebrates and Geosciences; even our pet Entomologist. No luck.

On the off-chance that our Live Exhibits manager had seen something similar on fieldwork, I emailed through the photographs to him, and he shared them round the office. Victory! Gentleman-and-scholar Adam Elliot knew immediately what they were. It turned out that our enquirer's by-the-by remark about the crayfish was the salient information – these "fossilised champignons" are freshwater crayfish gastroliths. When preparing to shed, the crayfish forms these stones to store the calcium they will need to help form their new exoskeleton. After they've shed (a process called ecdysis – remember that one for word games), they reabsorb this calcium to help create their new shell. These particular examples are very, very large.

Crayfish gastroliths Crayfish gastroliths, brought into the Discovery Centre for identification.
Image: Wayne Gerdtz
Source: Museum Victoria
 

This blog post from the WA Museum gives a great rundown on how the process works, and includes a photo of some smaller gastroliths from a similar identification request.

So there you have it, mystery solved. We'll keep an eye out for more oddities – I've always liked them best.

The Adventures of Ally, the albino Possum

Author
by Max
Publish date
21 November 2012
Comments
Comments (10)

One of the many questions we are asked in the Discovery Centre is about the many and varied birds and mammals people sight in their own surburban backyards.  One such enquiry came to us from Steve from East Brighton who had spotted an albino possum in his garden.

Ally, the albino possum Ally, the albino possum
Image: Steve Mitchelmore
Source: Steve Mitchelmore
 

In February 2012 Steve discovered an albino baby brush-tail possum in his backyard. He wanted to know how rare they were as he had been observing possums for years, and this is the first albino one he had seen. One of our experts responded with the following;

Albino mammals are not totally unknown; we have received specimens at about a three year interval on average. Once the gene is introduced into a local population then their occurrence becomes a bit more periodic although only about once in a generation. Because they are not camouflaged as well as their parents or siblings they are readily detected by predators and could be easily taken as prey. A true albino will also have poor eyesight due to the lack of pigmentation in the eye again making them susceptible to predation. It will be interesting to follow this young animal and see how it survives such traumas.

Ally, the albino possum Ally, the albino possum
Image: Steve Mitchelmore
Source: Steve Mitchelmore
 

To which Steve responded;

About three weeks ago I noticed the small tail and one paw protruding from the mother's pouch seemed unnaturally pale in colour, then last night the juvenile, creamy white with deep red eyes, was on its mother's back...

P.S. Regarding predators, do you know if Powerful Owls inhabit the East Brighton area?

To which our expert replied;

I am unsure about the Powerful Owl’s situation in East Brighton but I can say that they have been seen/heard in many Melbourne suburbs. So if the area concerned is heavily vegetated – that is with large trees then there is every possibility that one of these large owls will make its presence felt.

Early in July, Steve sent the following update;

... you mentioned that it would be interesting to follow her development and any 'traumas' she may endure.  She still comes by almost every night, having been AWOL on only six or seven occasions since late January.  She has the un-original name of 'Ally' (as in Ally the Albino)...  As for traumas, so far so good, apart from when she fell into the pool three nights ago.  Luckily the water level was so high following all the recent rain that she had no trouble getting herself out. 

Ally, the albino possum Ally, the albino possum
Image: Steve Mitchelmore
Source: Steve Mitchelmore
 

Then in late July, he sent in his last update;

Hate to be the bearer of bad news, but . . . Sadly, Ally has not been sighted since Monday night...Some months ago she disappeared for three nights straight, but I won't hold my breath after seven.  I've made numerous calls to local vets, DSE, Wildlife Victoria...Animal Rescue etc. all to no avail and searches of neighbouring yards for fur or remains have also been fruitless... I'm still amazed she survived as long as she did.  Anyway, it was certainly an enjoyable (and educational!) six months.  She will be sadly missed. Once again, thanks for your time and response to my emails.

Got a question? Ask us!

UPDATE: Ally has been spotted again!

Links

WILD: Amazing animals in a changing world

Bioinformatics

Mystery object?

Author
by Nicole D
Publish date
29 July 2012
Comments
Comments (0)

 Your Question: What is this mysterious object I found on the beach?

One of the most popular services that Discovery Centre provides is identifications. We get asked by members of the public to identify a wide range of unusual objects and specimens on a daily basis. Many are quite straightforward for our experts but others, such as this one, can be trickier. Usually we can tell whether or not something has been made by human hands or is naturally occurring but not always!

Mystery object Mystery object brought into the Discovery Centre for identification
Image: Nicole Davis
Source: Museum Victoria
 

A little while ago one of our enquirers brought in this unusual egg-shaped specimen that he'd found in the Red Bluff cliffs at Black Rock.

  Mystery object Mystery object brought into the Discovery Centre for identification
Image: Nicole Davis
Source: Museum Victoria
 

It was filled with sand and appeared to be a hard material with a thin flexible coating. Due to its findspot at the beachside, the enquirer thought it might be the preserved egg of sea creature, perhaps a turtle.

http://www.flickr.com/photos/usoceangov/5514927530/

We sent the specimen to one of our mammalogists and then to an ichthyologist (that’s someone who studies fish). Both of them confirmed that it definitely wasn’t an egg and, furthermore, was an object made by humans rather than a naturally occurring specimen.

The object then went to our History & Technology curators who speculated on what it might be. Was it a globe, some kind of fishing lure or something else entirely? After having a bit of a look, the staff concluded that it was indeed a light bulb. But it was a very specific type of bulb – one that belonged to an old flash for a camera that might have looked something like this:

http://www.flickr.com/photos/captkodak/271841556/

Mystery solved!

Got a question? Ask us!

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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