Chameleon of the sea
- University of California, Davis, Sacramento, CA, USA; irschwab@ucdavis.edu
Ambush predators possess the advantage of surprise and, when coupled with speed, are devastatingly successful. Speed and accuracy require adept sensory mechanisms, most commonly vision, and excellent vision usually requires large eyes especially among the vertebrates. But evolution has found creative, often unique, solutions for the smaller vertebrates that survive in the highly competitive world of predation. The sandlance, Limnichthyes fasciatus, has just such a unique solution.
L fasciatus is no more than 20–40 mm in length and hides in the loose sand of the shallow reefs of the Indo-Pacific. Using creative adaptations, this benthic predator will explode from its camouflaged hide among the coral rubble in a brief and extremely rapid sally to attack small planktonic prey.
Most fish have all the refractive power of their eye concentrated into a round crystalline lens (BJO covers May 2002 and Oct 2004) with little or no refractive effect from the cornea since the refractive index of the cornea and seawater is approximately the same. L fasciatus, though, has a very thick cornea representing approximately one seventh of the …
