With thirty thousand tiny eyes…
(Image above by Craig Dylke of Art Evolved)
The Cambrian Emu Bay Shale of Australia is something of an eye mine, it seems. After a previous paper on beautiful fossils of Emu Bay arthropod eyes (Lee et al., 2011), scientists now report the exquisitely preserved compound eyes of none other than the iconic Cambrian predator, Anomalocaris.
(Any excuse to post pictures of Anomalocaris is a good excuse 😛 This one is also Craig Dylke’s, and shows Anomalocaris on the hunt among a shoal of small arthropods.)
We’ve known for a long time that anomalocaridids (close relatives of arthropods) had well-developed eyes, but previously published fossils didn’t include details like individual facets. The three eyes (one pair and a loner) described in Paterson et al. (2011) clearly show thousands upon thousands of tiny, tightly packed hexagonal facets.
Each eye had over 16 000 little lenses, and the authors suspect that many more could have been destroyed in the process of flattening a bulb-shaped object into a two-dimensional fossil. In life, the gaze of Anomalocaris may have been just as unsettling – and its vision just as sharp – as that of a living dragonfly. Except this guy could grow longer than your leg.
(Oh hai? Dragonfly by Arturo Nikolai, from Wikimedia Commons)
The eyes were found without a body, but their shape is a good match for less well-preserved anomalocaridid eyes that were still attached to the animal. Also, being around an inch wide at their widest, they are way too big for anything else known from the Emu Bay fossil beds.
So it seems anomalocaridids hunted with some of the sharpest eyes of any arthropod, living or extinct. As if they weren’t badass enough already 😀
(Also, wow, the same team made Nature with their Cambrian eyes twice in the same year.)
Lee MSY et al. (2011) Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia. Nature 474:631-634
Paterson JR et al. (2011) Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature 480:237-240