July 6, 2014 | David F. Coppedge

Mantis Shrimp Baffles Evolutionists

Stomatopods, popularly known as mantis shrimp, possess several unique abilities that defy evolution.

The googly-eyed mantis shrimp, a colorful inhabitant of reefs important for coral ecology, is a living wonder in more than one way.  In previous entries, we reported that they are the only animals known to detect circularly polarized light (3/31/08).  Their limbs also operate clubs that are so powerful, they can break aquarium glass in a single strike (6/13/12).  Now, a new paper in Current Biology explains that mantis shrimp use a natural “sunscreen” protein as spectral filters, allowing them to see 12 channels of light using 16 types of photoreceptors (compared to the 3 in our retinal cones).

“Though the reason for the mantis shrimp’s complex visual perception is poorly understood, one possibility is that the UV detection could help visualize otherwise difficult-to-see prey on coral reefs,” a short report on Science Magazine says.  “Many organisms absorb UV light—these organisms would be easy to spot as black objects in a bright world.”  One whack with their claw hammers would make for quick lunch.

This was an “unexpected discovery,” EurekAlert says.  Perhaps this compensates for the small brain of these creatures:

Their complex eyes, which include 16 or more types of photoreceptors in all, may provide them with a complex color and polarization visual system without a big brain to post-process lots of information. In other words, their eyes may sense and respond to complex visual inputs without the need to think very hard about it, [Michael] Bok [University of Maryland] explains.

How did these unique features come about?  Michael Bok and the three other authors of the paper have no idea:

The ecological and evolutionary factors that drove the development of such a singularly elaborate UV spectral tuning arrangement in N. oerstedii are poorly understood, but the complexity and precision of this system certainly suggest an importance to the stomatopods’ lifestyle.

As for that lifestyle, they had some suggestions, even though it’s impossible to know how these amazing creatures experience their world:

Stomatopods are aggressive predators, with one of the most powerful attack strikes in nature, and they have a surprising repertoire of complex social interactions. It is likely that UV sensitivity plays a role in many of their visually guided behaviors. Recent behavioral experiments have suggested that stomatopods may use their finely tuned color receptors as a temporally rapid means of color recognition. Provocatively, signaling at exceptionally short UV wavelengths could provide stomatopods with a rapid and covert medium of communication, outside the light-analysis range of any other marine animal.

The authors never elaborated on what “evolutionary factors” might have produced the “singularly elaborate” visual system of the mantis shrimp.  The phrase “poorly understood” can be interpreted as “clueless,” because they would have suggested some clues if they had any.

We’re not going to accept the standard Darwinist answer, “It evolved because it evolved” (6/26/13).  That would be a science show-stopper.  The show that has stopped is the Darwin Light and Magic Theater.


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