Cambrian Explosion: another weird animal (Introduction)

by David Turell , Tuesday, January 23, 2018, 14:44 (2285 days ago) @ David Turell

Complex and weird Cambrian forms keep appearing:

https://www.livescience.com/61488-ancient-worm-evolutionary-mystery.html?utm_source=ls-...

"An eyeless, alien-like worm with two tentacles sprouting out of its head and covered in so many bristles it looked like a kitchen brush would have been quite a sight during its heyday as it scarfed down seafloor mud some 508 million years ago.
Scientists discovered the exquisitely preserved remains of the bizarre, soft-bodied creature in British Columbia, Canada. Like other bristle worms, the newfound critter has hair-size bristles poking out of its body. "However, unlike any living forms, these bristles were also partially covering the head, more specifically surrounding the mouth," the study's lead author Karma Nanglu,...said in a statement.

"By analyzing the fossils (and intriguing noggin), researchers were able to solve an evolutionary mystery about how ringed worms, a group that includes modern earthworms and leeches, developed their heads. The newly identified critter "seems to suggest that the annelid head evolved from posterior body segments that had pair bundles of bristles, a hypothesis supported by the developmental biology of many modern annelid species," Nanglu said.

***

"The bristly worm was tiny, just 1 inch (2.5 centimeters) long. But this teeny body sported a ton of bristles — each of its up to 25 body segments sported 56 bristles apiece, and it also had two long tentacles on its head. Smaller antennae between its tentacles likely helped the worm scan the area directly in front of it, while the tentacles could extend farther, Nanglu said.

"The scientists named the critter Kootenayscolex barbarensis. The genus name references Kootenay National Park in British Columbia, where Marble Canyon is located, and includes " scolex," the Greek word for "worm."

***

"K. barbarensis was likely a deposit feeder that engorged itself with mud on the seafloor, Nanglu said. "These organisms funnel mud into their mouths that they then sift through for organic material to feed on," he said. "We get evidence for this way of life from the well-preserved gut of Kootenayscolex, which often preserves much more darkly [in color] compared to the surrounding tissue.'"

Comment: The usual result: a complex animal with no precursors, showing evolution is not a process of Darwin tiny steps.