RE: And no, Creatards..."Adam and Eve" Did Not Ride Them!
May 12, 2015 at 12:25 am
(This post was last modified: May 12, 2015 at 12:35 am by Anomalocaris.)
Crabs carry compound eyes on short stalks. They can move their compound eye stalks, and retract tgeir eyes into recesses in their shells.
We don't know whether the eye stalks of anamalocarids can move or not. Also not all anamalocarids appeared to carry their eyes on stalks. Some appears to have their compound eyes set directly into their heads. It has been suggested eye stalks in anamalocarids correlates with head appendages suggestive of active predation, where as stalkless eyes set directly into the head correlates with head appendages suggestive of filter feeding. This suggests putting eyes on stalks is an adaptation geared towards hunting. Perhaps it sets the eyes further apart for better depth perception.
Also, some predatory anamalocarids had the highest number of facets per compound eye ever discovered in fossil record of any kind. This suggests the compound eyes of these anamalocarids had the highest visual resolution ever achieved with compound eyes. This also argues the vision of anamalocarids might have been sharp enough for them to be able to utilize stereoscopic depth perception.
The examples of anamalocarids we have from Devonian are quite small, a few inches long. It showed considerable specialized adaptation, with generic repetitive body parts of their Cambrian ancester evolved into specialized parts clearly serving different functions depending on where they are along the body. They were probably still pelagic predators, but were certainly no longer apex predators like they probably were during Cambrian.
We don't know whether the eye stalks of anamalocarids can move or not. Also not all anamalocarids appeared to carry their eyes on stalks. Some appears to have their compound eyes set directly into their heads. It has been suggested eye stalks in anamalocarids correlates with head appendages suggestive of active predation, where as stalkless eyes set directly into the head correlates with head appendages suggestive of filter feeding. This suggests putting eyes on stalks is an adaptation geared towards hunting. Perhaps it sets the eyes further apart for better depth perception.
Also, some predatory anamalocarids had the highest number of facets per compound eye ever discovered in fossil record of any kind. This suggests the compound eyes of these anamalocarids had the highest visual resolution ever achieved with compound eyes. This also argues the vision of anamalocarids might have been sharp enough for them to be able to utilize stereoscopic depth perception.
The examples of anamalocarids we have from Devonian are quite small, a few inches long. It showed considerable specialized adaptation, with generic repetitive body parts of their Cambrian ancester evolved into specialized parts clearly serving different functions depending on where they are along the body. They were probably still pelagic predators, but were certainly no longer apex predators like they probably were during Cambrian.
