I imagine Au Ra horns to function similar to narwhal tusks: innervated sensory organs with nerve endings that connect stimuli to the brain. Following this, then other than hearing (which is the detection of vibrations made in the air) an Au Ra would be able to use these organs to sense changes in humidity and temperature, to a limited extent. Being more sensitive to sound in addition to sensing fluctuations in the air would be in line with the lore blurb that described Auri horns as giving them "enhanced spacial recognition".
At the same time, I also imagine that the functions besides hearing are mostly vestigial for most Au Ra. Certainly, Au Ra who, for example, lived in extremely low-light environments would have enhanced senses and thus their horns would be much more sensitive at detecting things like body heat or the movement of air caused by external motion, but unless the Au Ra's environment demanded such functions be necessary in terms of natural selection--for example, freezing ice is often fatal to large groups of narwhals, therefore narwhal tusks are sensitive to changes in salinity to detect whether ice is beginning to form--I doubt that the aforementioned "enhanced spacial recognition" really received that much development evolutionarily.
As far as the surface, I think it'd be...well, matching their scales in texture. Tough, rough, and somewhat chitinous. These are large and prominent appendages, in sharp contrast to human ears which are small in relation to the head and typically flat. Au Ra horns by necessity would have to be hardened and reasonably durable, perhaps encased in a layer of hollow but tough bone or something similar.
At the same time, I also imagine that the functions besides hearing are mostly vestigial for most Au Ra. Certainly, Au Ra who, for example, lived in extremely low-light environments would have enhanced senses and thus their horns would be much more sensitive at detecting things like body heat or the movement of air caused by external motion, but unless the Au Ra's environment demanded such functions be necessary in terms of natural selection--for example, freezing ice is often fatal to large groups of narwhals, therefore narwhal tusks are sensitive to changes in salinity to detect whether ice is beginning to form--I doubt that the aforementioned "enhanced spacial recognition" really received that much development evolutionarily.
As far as the surface, I think it'd be...well, matching their scales in texture. Tough, rough, and somewhat chitinous. These are large and prominent appendages, in sharp contrast to human ears which are small in relation to the head and typically flat. Au Ra horns by necessity would have to be hardened and reasonably durable, perhaps encased in a layer of hollow but tough bone or something similar.
