Researchers say these tubes were lost in the lineage that resulted in modern-day acorn worms, but were retained through graptolites and pterobranchs.
The fossils, Spartobranchus tenuis, are a member of the acorn worm group.
Hemichordates are a type of marine animal split into two groups: the acorn worm, which live in burrows, and the pterobranchs, which live in a tubular structure anchored to the ocean floor.
Shallow water acorn worms live in burrows and are rarely seen, whereas deep sea species browse on the sea floor leaving spiral poo traces that resemble crop circles.
There is much interest in the acorn worms from the point of view of understanding the early evolution of the vertebrates.
A reddish-purple acorn worm with large lips either side of its head region reminded researchers of floppy-eared Star Wars character Yoda while pupurata is Latin for purple and describes its colorful hue.
Allapasus isidis is the name given to a white acorn worm which was named after the NERC-owned remotely operated vehicle, ROV Isis, which collected the specimens from the ocean.
Tergivelum cinnabarinum is the name given to a vibrant scarlet-orange acorn worm -- cinnabarinum is Latin for cinnabar which is a red colored mineral.