Cryptocentrus nanus is a new species of watchman goby recently described from Fiji. Clocking in at a whopping two inches long when full grown, the nano watchman goby is the smallest species of what we tend to think of when someone mentions a shrimp-associated, sand dwelling aquarium goby.
Being all-black Cryptocentrus nanus is not patterned in any way and easily confused with dark specimens of common watchman gobies like C. cryptocentrus. The only reason the taxonomists recognized their tiny 49mm samples as being full grown was from the presence of mature gametes in the type specimens.
What makes C. nanus unique is the presence of special teeth on the roof of its mouth called vomerine teeth which had previously been used to single out the attractive and colorful Stonogobiops gobies like S. yasha. While not much of a looker, the all black C. nanus is interesting for showing us that watchman gobies can get nano too! [JOSF]