Pillar of Intestines | BBC Wildlife Magazine

Ciona sea squirts against a black background. The squirts appear like tubes with a tapered end

Ciona intestinalis (sea squirts). Screenshot from a video by Nipam Patel, Robert Zeller, BioQuest Studios, and the MBL

By Melissa Hobson | BBC Wildlife Magazine March 10, 2025

Researchers have shared a captivating video of tunicates – also known as sea squirts – developing from embryos.

In the footage, Ciona sea squirt embryos can be seen developing under the microscope before showing what it looks like when adults feed by filtering particles from the water – like a translucent underwater sausage with hiccups. Their peculiar appearance is why their Latin name translates to 'pillar of intestines'. ...

A timelapse showing growth of transgenic Ciona sea squirt embryos followed by footage of adult Ciona feeding. Created as part of the MBL Embryology course in the summer of 2018, the video starts 7-8 hours after fertilization and illustrates the rapid development of ascidians—a hatched tadpole larva appears 18 hours after fertilization. The fluorescent proteins expressed by the transgenes accumulate in the cells’ nuclei (the spots in the video), making the cells easier to study. Researchers have a good understanding of the relatively low number of cells (~2,500) in tadpole larvae, making individual cells and organs easy to identify and study, even during embryogenesis. Credit Nipam Patel, Robert Zeller, BioQuest Studios, and the MBL

“These animals have a close evolutionary relationship to vertebrates, but their relatively simple bodies and compact genomes make them an excellent research subject,” says Nipam Patel, Director at the MBL. Read the rest of the article here.

Source: Pillar of Intestines | BBC Wildlife Magazine