In biology, setae are any of a number of different bristle- or hair-like structures on living organisms.
Setae on the foreleg of a mayfly
Close-up of the underside of a gecko's foot as it walks on vertical glass
Common house geckos mating on a vertical glass window and showing lamellae under the feet
Pointed setae protruding into the fertile surface tubes of the bracket fungus Phellinus gilvus. Click on image
The annelids, also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.
Annelid
This sabellid tubeworm is budding
Burgessochaeta setigera
Phylogenetic tree of early lophophorates