{"id":987,"date":"2026-07-30T13:39:00","date_gmt":"2026-07-30T04:39:00","guid":{"rendered":"https:\/\/onepress.co.kr\/index.php\/briefing\/2026-07-30-early-cambrian-cephalopod-en\/"},"modified":"2026-07-30T13:39:00","modified_gmt":"2026-07-30T04:39:00","slug":"2026-07-30-early-cambrian-cephalopod-en","status":"publish","type":"briefing","link":"https:\/\/onepress.co.kr\/index.php\/briefing\/2026-07-30-early-cambrian-cephalopod-en\/","title":{"rendered":"Did the octopus family\u2019s \u201csubmarine\u201d start at just a few millimetres?"},"content":{"rendered":"

2026-07-30 13:39 KST<\/strong><\/p>\n

A millimetre-sized fossil from a very distant branch of the octopus and squid family preserves what may be an early device for controlling buoyancy.<\/p>\n

It is a candidate for the earliest cephalopod, not a proven direct ancestor of modern octopuses or a fully developed submarine system.<\/p>\n

What was found?<\/h2>\n

Researchers described Eoceras shaanxiense from an early Cambrian rock formation in South China. Its straight, cone-shaped shell was only a few millimetres long.<\/p>\n

Scanning electron microscopy and high-resolution micro-CT revealed several internal partitions that formed chambers. A thin tube also ran near the shell edge and linked the chambers.<\/p>\n

Why compare it to a tiny submarine?<\/h2>\n

A living nautilus rises and sinks by changing the liquid and gas inside its shell chambers. A thin strand of tissue called a siphuncle helps manage that process.<\/p>\n

The tube in Eoceras appears to have connected its chambers through minute canals. The team interprets it as a candidate primordial siphuncle, an unfinished-looking stage of the same basic system.<\/p>\n

\"Explanatory
ONEPRESS explanatory reconstruction: it visualizes the chambers and peripheral tube of Eoceras; it is not a photograph or a confirmed life appearance.<\/figcaption><\/figure>\n

Why connect it with octopuses?<\/h2>\n

Octopuses, squid, cuttlefish and nautiluses are all cephalopods. In early fossils, the combination of a chambered shell and a tube linking those chambers is a crucial clue to the group.<\/p>\n

The oldest widely accepted cephalopods came from the late Cambrian. If this interpretation holds, the cephalopod stem reaches back into the early Cambrian.<\/p>\n

Does that mean it swam like a squid?<\/h2>\n

No. Its anatomy suggests that it may have adjusted buoyancy, but there is no evidence that it swam rapidly, used jet propulsion or chased prey.<\/p>\n

\u201cSubmarine\u201d is an analogy for the physical principle. The study examined fossil anatomy; it did not observe the animal moving.<\/p>\n

What is still uncertain?<\/h2>\n

Modern cephalopod siphuncles are continuous, while this fossil\u2019s tube is segmented. The paper therefore calls it a candidate primordial siphuncle, not a settled identification.<\/p>\n

More fossils are needed to establish its exact place on the family tree. The firmest result is a glimpse of chambered buoyancy anatomy being assembled at a very early stage.<\/p>\n

Official primary sources<\/h2>\n

Primary source: Nature original research article<\/a><\/p>\n

Primary source: Dryad micro-CT dataset and methods<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

An early Cambrian fossil from China has chambered shell anatomy and a candidate primitive tube for controlling buoyancy.<\/p>\n","protected":false},"featured_media":0,"template":"","meta":[],"class_list":["post-987","briefing","type-briefing","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/briefing\/987","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/briefing"}],"about":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/types\/briefing"}],"wp:attachment":[{"href":"https:\/\/onepress.co.kr\/index.php\/wp-json\/wp\/v2\/media?parent=987"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}