New insights into anatomy of ancient tentacled creature

Illustration of Cotyledion tylodes living as a group

Related Stories

Scientists have shed light on a peculiar tentacled marine creature that lived 520 million years ago.

Experts thought that Cotyledion tylodes may have belonged to the jellyfish-like cnidarian group.

But new anatomical evidence from the animal's fossilised remains suggests the species was an early member of the group of small marine organisms called entoprocts.

The findings are published in the journal Scientific Reports.

Results of the study, by an international research team, suggest that entoprocts appeared earlier than previously thought.

Wonders of the Cambrian period

Cambrian creatures illustration

Marvel at creatures of evolution's 'big bang'

When was Wales underwater?

See how trilobites used life's first complex eyes

Entoprocts are small organisms that feed by straining food particles from water.

Scientists analysed hundreds of Cotyledion tylodes fossils preserved in the Chengjiang fossil site in Yunnan province, China, dating from the Cambrian geological period (545 to 495 million years ago).

To date, the only uncontested fossil entoproct comes from the Jurassic (205 to 142 million years ago).

However this reinterpretation of Cotyledion tylodes as an entoproct places the fossil record of this group in the earlier Cambrian period.

Some anatomical characteristics of Cotyledion tylodes are comparable to those of modern entoprocts, especially the presence of a U-shaped gut with a mouth and anus surrounded by a crown of tentacles.

"This is... the first time to confirm that [Cotyledion tylodes] had a U-shaped gut accommodated in the calyx cavity," said Zhifei Zhang, from Northwest University, Xi'an city, Shaanxi Province, China, who worked on the study.

Cotyledion tylodes fossil Cotyledion tylodes fossil from the Chengjiang site

The bizarre-looking creature also had a goblet-shaped body with an upper cup-like cavity and lower elongated stalk, with which it "attached to exoskeletons of other organisms", explained Mr Zhang.

Cotyledion tylodes was larger than extant entoprocts, measuring between 8mm and 56mm in height. Its body was covered in external, hardened structures called sclerites, which are not found on modern entoprocts.

Evolutionary big bang

The "Cambrian explosion" saw the relatively sudden appearance of abundant life forms in the sea.

Mr Zhang said that the team's reinterpretation of Cotyledion tylodes as belonging to the Entoprocta phylum adds further support to the idea that "nearly all the living phyla of animals suddenly appeared in the Cambrian".

However, few fossil representatives of Lophotrochozoa (the superphylum containing the entoprocts group of animals) have been found in Cambrian fossil records.

Join BBC Nature on Facebook and Twitter @BBCNature.

More on This Story

Related Stories

More from nature

  • Cardinal fish and ostracodFish filmed spitting 'fireworks'

    Film crew captures ostracods' spectacular defensive lightshow that makes predatory fish spit them out.

  • Arapaima'Locally extinct'

    A giant fish which used to dominate the Amazon river is now absent in many areas


  • DragonflyRapid reactions

    Dragonfly's super quick reactions recorded in slow motion by BBC film-makers


  • Wingless adult male of the midge Belgica antarcticaExtreme survivor

    Antarctic midge's small genome may be an adaptation to its extreme environment


  • Myotis midastactus specimen (previously identified as Myotis simus)Golden discovery

    A bat from Bolivia is described as a new species by scientists


  • Dinosaurs 'shrank' to become birds

    Huge meat-eating, land-living dinosaurs evolved into birds by constantly shrinking for over 50 million years, new research shows.

  • Would we starve without bees?

    Honey bees are under threat, and as pollination significantly contributes to the food we eat, what would we do without them?

  • Eggshells may act like 'sunblock'

    Birds' eggs show adaptations in pigment concentration and thickness to allow the right amount of sun for embryos, scientists say.

  • Female shrimps are more aggressive

    Female snapping shrimps are more aggressive than males when defending their territories despite their smaller claw size, a study shows.

BBC iWonder

  • Honey bee close-upInsect intelligence

    Are honey bees as smart as your sat nav?

  • Tyrannosaurus rex skull (c) Mark Williamson / Science Photo LibraryDinosaur dynasty

    One group of dinosaurs survived and their descendants can be seen all around us today


  • Brown rat cluse upRise of the rodent

    Reports of giant, 'super rats' are filling the headlines. But why are we being overrun by rats?


  • Cuckoo portraitHoliday hotspot

    What makes the UK such an attractive destination for visiting wildlife?


Awesome! And there's nothing common about such beauty.

Elaine Bernon on Facebook comments on the trio of common blue butterflies in our Photo of the Day.

Things To Do

RUN BY THE BBC AND PARTNERS

More Nature Activities >

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.