Good news, everyone: Biologists have discovered a species of marine worm that, when still in its larval stage, is nothing more than an algae-gobbling, disembodied head.

Most animals have at least a semblance of an adult-like body when they re young.

The marine acorn worm Schizocardium californicum lives for months as nothing more than a head, swimming around chomping algae.

The discovery of this odd mode of development is shedding new light on a poorly-understood organism, and on how early life may have evolved on Earth.

Larval animals like the acorn worm undergo indirect development, changing dramatically from their initial birth stage to the adult stage the caterpillar turning into a butterfly is a supreme example .

In an effort to understand this process a bit better, biologists Paul Gonzalez and Chris Lowe from Stanford s Hopkins Marine Station took a closer look at S. californicum, a creature that s notoriously difficult to study because of its slow and protracted larval stage.

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