The mystery of a bizarre creature dubbed the “alien goldfish,” which has baffled fossil experts for decades, may have been solved, according to scientists who say the animal appears to have been some type of mollusk.
Typhloesus wellsia lived about 330 million years ago and was discovered in the late 1960s at the Bear Gulch limestone fossil site in Montana, after which the remains of other species were identified.
But with features such as a rugby ball-shaped body up to 90 mm (3.5 in) long, a fin at the back, no spine or anus, and the lack of a shell, the anatomy of typhus left scientists confused about where it belonged on the tree of life.
The Discovery of Tiny Teeth Inside typhus fossils that eventually turned out to be the remains of a last meal of small, eel-shaped, extinct fish known as conodonts had added to the confusion.
dr. Jean-Bernard Caron, a co-author of the study from the Royal Ontario Museum, said:[Typhloesus] was like an orphan in the tree of life.”
But the researchers say a tooth structure found in the animals’ intestines could help clear up the confusion.
Caron said: “What we think is that [Typhloesus] could be some kind of unique group of mollusks that evolved during the Carboniferous period [period] and eventually extinct.”
In the journal Biology Letters, Caron and his colleague Prof. Simon Conway Morris of the University of Cambridge describe how to get about a dozen copies of typhus housed in the Royal Ontario Museum, many of which had not been studied before.
In the midst of several specimens, they found evidence of a feeding device similar to the serrated ribbon — radula — seen in mollusks today. Located at the forefront of typhusthe 4 mm long structure consists of two rows of approximately 20 triangular teeth, curved backwards.
The researchers say it is likely typhus turned the structure inside out and projected it outside the body to catch prey.
“An analogy here [is] the tongue of a lizard, for example catching an insect. It’s very fast and it puts food in the mouth,” said Caron, adding that it is possible in addition to consuming conodonts. typhus ate algae from the seabed.
But Caron said the case is not completely closed. “We know it’s some sort of mollusk, but it’s still a very strange looking mollusk,” he said, adding that it’s unlikely everyone will agree with the team’s interpretation that the creature could be some sort of gastropod. can be – a family that includes snails and slugs.
dr. Luke Parry, a paleontologist at Oxford University who was not involved in the work, welcomed the study.
“The radula they identified seems attractive to me, so this [is] effectively solved a paleontological mystery, even if the authors can’t place the fossil in the gastropod tree of life with much precision,” he said.
Prof Mark Purnell, of the Center for Paleobiology at the University of Leicester, said that while the radula is convincing, it remains unclear whether typhus was a mollusk, as different species of animals independently developed radula-like features.
“It’s still a very strange animal,” he said. “[The researchers] have found some tantalizing new information, but it’s far from a slam-dunk affair in terms of knowing for sure what this weird thing is.