i am back with another possible taxonomic classification. The San'Shyuum!

the San'Shyuum are probably the Covenant species with the least consensus on what they are.

amphibians?

reptiles?

birds?

mammals?

fish?

i think that they most likely evolved from mammals, specifically from the order Perissodactyla or Odd-toed ungulates. (the order which includes Rhinosceroses,zebras and tapirs)

1.San 'Shyuum have fur/hair: a typical mammal characteristic

2.San 'Shyuum are warmblooded

3.they give life births

4 they both have three digits on their hands: just like Rhinos San'Shyuum have thee digits on their hands this can good be observed in the first cutscene from Halo 2.

5.Differentiated teeth: just like the sangheili, they do not have pointy reptile-like teeth but different types, such as incisors, canines, and molars.

6.Lower jaw composed of a single bone: like humans or other mammals their lower jawbone is only composed from a singular bone, the dentary.

7.reproduction cycle San'shyauum have a hard time getting pregnant and long gestation periods, just like Rhinos.

1. more or less a sidenote: they have a special taste for alcohol. like Humans.

in summary, the San'Shyuum are a group of highly intelligent bipedal Rhinoceroses who genetically degenerated due to inbreeding and not being physically active.