‘Severed finger’ mystery solved by scientists at Darwin museum

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The now cleaned and classified mystery item (left) sits alongside another sea squirt in the MAGNT collection.

The Museum and Art Gallery of the Northern Territory (MAGNT) has begun classifying the once mysterious object, rendering it decidedly less of a finger doppelganger.

The decomposed sea creature attracted national media attention this month after it washed up on a Top End beach.

A man was walking his dog on the shoreline at Lee Point, north of Darwin, when his animal took an interest in the weird specimen.

The dog walker believed he had unwittingly discovered the remains of a murder victim and contacted Northern Territory police.

Casuarina Police station officers were baffled and divided by the mystery item, which was sent off for forensic examination and then pathology after initial tests came back inconclusive.

At the time, pathology concluded the item was some sort of plant, and it was donated to the MAGNT for further analysis.

A police photo then posted on social media fuelled further speculation that the item was a piece of coral called Alcyonium digitatum, otherwise known as dead man’s finger.

But the museum’s team of scientists had a different professional opinion.

What is it then?

The police photo by itself proved to be something of a red herring, and Sue Horner, a collection technician in the MAGNT natural sciences department, said it took about “30 seconds” for them to identify the specimen’s real identity.

“When we physically got it, we were able to see that it was actually kind of different to what the [police] photo showed,” Ms Horner told ABC Alice Springs.

“For example, in the photo, it appeared there was a fingernail.

“That appeared to have just been a bit of mollusc shell that had been stuck to it, but wasn’t part of the animal.”

Ms Horner said it was understandable that police pathology incorrectly identified the decomposed and eroded sea squirt as a type of plant.

“It’s not [just] that it looks like a plant, but it’s the only animal in the whole animal kingdom that has this plant structural material called cellulose as part of its body,” she said.

“That makes this pretty damn unique.”

Sea squirts grow up to seven centimetres long and feature a feeding siphon at both ends of their tubular body.

“One [siphon] to suck water in and one to push water out,” said Ms Horner.

“They’re very good at sucking, and inside their body is basically hollow [with] a large reservoir of water.

“Lining the inside of the body is a pharynx… sea creatures get caught in this network and from there they get pushed into the animal’s gut.

“They’re a very variable group and they tend to look just ‘blobby’.

“Certainly, if you squeeze them, they will squirt you.

Sea squirt still a slight mystery

There are roughly 2,300 types of sea squirts, scientifically known as ascidians, of which 90 are found in Darwin’s harbour.

MAGNT has been unable to identify the famous sea squirt’s specific species strain due to its decomposed state.

Ms Horner said the sea squirt likely washed up on the beach after a recent Top End monsoon, which would have disrupted material on the reef.

It will soon join the museum’s existing collection of sea squirts but will not be given a name, unlike other famous items at MAGNT.

“We don’t give them personalised names, unlike Sweetheart [the crocodile] who is in our galleries,” Ms Horner said.

“[But] we will probably keep records of all the media exposure it’s gotten.”

Source: ABC News