Modeled in 3D

(Image credit: Yu Liu et al.)A fossil of an arthropod larva estimated to be 520 million years old was found in Chengjiang, China. Preserved in three dimensions, it provided researchers with an unprecedented level of detail for describing the creature's body.

In this image, 3D models rendered from CT scans show dorsal and ventral views of the larva's body.

Making an impression

(Image credit: Y. Liu / R. Melzer / J. Haug)Three views of L. illecebrosa as seen from underneath the fossil: macrophotograph, scanning electron microscope (SEM) and fluorescence microsceopy.

All grown up

(Image credit: Yu Liu et al.)An adult form of the Cambrian arthropod, Leanchoilia illecebrosa. Researchers identified the new fossil as a juvenile of this species.

Hairy fingers

(Image credit: Joachim Haug)A close-up of the larva fossil shows hairlike structures on one of the "fingers" of the appendages on its head.

Swimming 'paddles'

(Image credit: Joachim Haug)Close-up of one of the two structures resembling paddles, near the larva's posterior. The researchers suggested that they might have been used for swimming.

Branching headgear

(Image credit: Yu Liu et al.)Micro-CT scanning revealed three branching parts on appendages attached to the larva's head.

From the top

(Image credit: Y. Liu / R. Melzer / J. Haug)Three views of L. illecebrosa as seen from the top of the fossil: macrophotograph, scanning electron microscope (SEM) and fluorescence microsceopy.

Model arthropod

(Image credit: Yu Liu et al.)Computed X-ray tomography (CT) scans allowed scientists to build a virtual 3D model of the arthropod larva, embedded in its rocky matrix.

Colorized se

(Image credit: Yu Liu et al.)In a colorized 3D model of the 2-mm-long larva L. illecebrosa, paired appendages become smaller and less developed as they move toward the larva's rear. These likely developed into legs later in the arthropod's life cycle.