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Bizarre fossil hauled its offspring around 'like kites' | Bizarre fossil hauled its offspring around 'like kites' |
(about 17 hours later) | |
A 430 million-year-old sea creature apparently dragged its offspring around on strings like kites - a baffling habit not seen anywhere else in the animal kingdom. | A 430 million-year-old sea creature apparently dragged its offspring around on strings like kites - a baffling habit not seen anywhere else in the animal kingdom. |
Scientists who discovered the fossil have dubbed it the "kite runner". | Scientists who discovered the fossil have dubbed it the "kite runner". |
Ten capsules tethered to its back appear to contain juvenile progeny, all at different stages of development. | Ten capsules tethered to its back appear to contain juvenile progeny, all at different stages of development. |
Reported in the journal PNAS, the many-legged, eyeless, 1cm animal is not directly related to any living species. | Reported in the journal PNAS, the many-legged, eyeless, 1cm animal is not directly related to any living species. |
"There isn't an animal today that it's essentially related to," David Legg, a palaeontologist from the Oxford University Museum of Natural History, told BBC News. | "There isn't an animal today that it's essentially related to," David Legg, a palaeontologist from the Oxford University Museum of Natural History, told BBC News. |
"It's what we refer to as being on a stem lineage. So it belongs to a group that would have evolved and diversified before the modern groups did." | "It's what we refer to as being on a stem lineage. So it belongs to a group that would have evolved and diversified before the modern groups did." |
In fact, Dr Legg added, although it clearly had the segmented body and exoskeleton of an arthropod, it was quite a job to figure out precisely where to position the little beast on the evolutionary tree. | In fact, Dr Legg added, although it clearly had the segmented body and exoskeleton of an arthropod, it was quite a job to figure out precisely where to position the little beast on the evolutionary tree. |
"Often you can look at a particular animal and say, that belongs to this group or that group. This one - we had no clue." | "Often you can look at a particular animal and say, that belongs to this group or that group. This one - we had no clue." |
Poor parenting? | Poor parenting? |
The fossil was dug up from a site in Herefordshire before being taken to Oxford and computerised. This process involved grinding away the specimen, slice by slice, and photographing each of those sections to assemble a 3D reconstruction. | The fossil was dug up from a site in Herefordshire before being taken to Oxford and computerised. This process involved grinding away the specimen, slice by slice, and photographing each of those sections to assemble a 3D reconstruction. |
Then, with this outlandish animal on their screens waggling its legs, long antennae and tethered capsules at them, Dr Legg and his colleagues set about categorising it using "compositional phylogenetics". | Then, with this outlandish animal on their screens waggling its legs, long antennae and tethered capsules at them, Dr Legg and his colleagues set about categorising it using "compositional phylogenetics". |
"You take its anatomy, code it into a data set and then run probabilistic methods on it, which will tell you how likely it is that something evolved in a particular way," he explained. | "You take its anatomy, code it into a data set and then run probabilistic methods on it, which will tell you how likely it is that something evolved in a particular way," he explained. |
This process suggested that Aquilonifer spinosus ("aquilo" means north wind or kite and the "-fer" suffix means carry) was a mandibulate: it belongs to the same broad group as modern insects, crustaceans and centipedes - but is not a direct ancestor. | |
"Nothing is known today that attaches the young by threads to its upper surface," said co-author Derek Briggs, from Yale University in the US. | "Nothing is known today that attaches the young by threads to its upper surface," said co-author Derek Briggs, from Yale University in the US. |
"Modern crustaceans employ a variety of strategies to protect their eggs and embryos from predators - attaching them to the limbs, holding them under the carapace, or enclosing them within a special pouch until they are old enough to be released - but this example is unique. | "Modern crustaceans employ a variety of strategies to protect their eggs and embryos from predators - attaching them to the limbs, holding them under the carapace, or enclosing them within a special pouch until they are old enough to be released - but this example is unique. |
"It shows that arthropods evolved a variety of brooding strategies beyond those around today - perhaps this strategy was less successful and became extinct." | "It shows that arthropods evolved a variety of brooding strategies beyond those around today - perhaps this strategy was less successful and became extinct." |
Before settling on the unlikely conclusion that they were tiny, floating, prehistoric prams, the team did consider other explanations for the attached pods; they might have been smaller, parasitic creatures of a different species, for example. | Before settling on the unlikely conclusion that they were tiny, floating, prehistoric prams, the team did consider other explanations for the attached pods; they might have been smaller, parasitic creatures of a different species, for example. |
But being tied on to Aquilonifer's tough and rather inedible shell would be a peculiar strategy for a hungry parasite. | But being tied on to Aquilonifer's tough and rather inedible shell would be a peculiar strategy for a hungry parasite. |
It was the variety of shapes seen among the 10 tethered babies that Dr Legg found most convincing. | It was the variety of shapes seen among the 10 tethered babies that Dr Legg found most convincing. |
"We see them develop and begin to resemble the adult form more and more, as they get bigger," he said. | "We see them develop and begin to resemble the adult form more and more, as they get bigger," he said. |
"I'm definitely convinced that that's what they were." | "I'm definitely convinced that that's what they were." |
Follow Jonathan on Twitter | Follow Jonathan on Twitter |
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