Sminthurinus aureus is a very common terrestrial springtail, less than 1mm long. It is particularly abundant on the underside of fallen leaves in autumn (as are other globular species). As the names suggests, it has an overall golden colour with no clear banding. Sminthurinus aureus has the 'small abdomen' (the animal's "tail end") wholly fused, while other UK Sminthurinus have a visible division between segments 5 and 6. The fourth antennal segment (ant4) is not subdivided.
S. aureus comes in a variety of colour forms with varying degrees of dark pigment, e.g. form ochropus: