One of the most obvious phenotypic features of S. peyoticus is the unusually bright blue skin pigment relatively rarely encountered amongst vertebrates, especially primates. Biological significance of this is still unclear, yet the issue has been under speculation and dispute ever since the first direct contacts with humans.

The bright blue colour stands out well in the forrestry habitats, indicating that the pigment must have some biological function other than a camouflage. One of the leading hypothesis suggests that the pigment is a warning signal for potential predators, an indication of acute toxicity in parallel to the defence systems of various toxic amphibians, snakes and insects. Despite of the low scientific value of mere phenotypic comparison, it is noteworthy that the tone and intensity of the S. peyoticus pigment is strikingly similar to the colour of the blue ”poison dart frog” (Dendrobates Azureus from South America) which produces batrachotoxin, a lethal alkaloidal steroid. However, this may be only coincidental, and without further evidence and detailed toxicological analysis, the existence and nature of the toxic compounds remains unclear.

An alternative hypothesis links the skin pigment to primary energy metabolism as a central part of a novel photosynthetic machinery: it has been suggested that the blue pigment could function as a part of a light-harvesting apparatus as an chlorophyll analog.

According to this model, S. peyoticus is an extraordinary facultative autotroph, and can convert sunlight directly into biochemical energy. In contrast to the green chlorophyll of plants, the blue pigment (sometimes trivally referred to as blauaphyll) would be more efficient in absorbing low frequency radiation energy of indirect sunlight, reflecting possible adaptation to evening activities.

...to be continued



Fig 1. Artist's view of S. peyoticus