Gulose is an aldohexose sugar. It is a monosaccharide that is very rare in nature, but has been found in archaea, bacteria and eukaryotes.
The passage states that Gulose is a type of sugar called an aldohexose, which means it has six carbon atoms and an aldehyde group. It's uncommon to find this sugar naturally but has been discovered in various organisms like archaea, bacteria, and eukaryotes.