I recently described myself as a “crustacean biologist” for a project I was working on. But whenever I do, I feel like such a sham, because I barely have a clue about critters like these...
I look at these and have a hard time believing that some of these are even animals.
These are examples of tanaidaceans. Haven’t heard of them? Don’t worry. I was at best only vaguely aware of their existence, too.
A recent paper by Blazewicz-Paszkowycz and colleagues is a nice little introduction to this little known group. They are almost all small burrowing animals living in sediment. They have almost zero ability to disperse, and so they become isolated and for mew species frequently as they become isolated. There are about 1,200 species known, but the rate of discovery has consistently increased. The authors estimate that for every known tanadacean species, there may be nine undescribed ones awaiting discovery.
Blazewicz-Paszkowycz M, Bamber R, & Anderson G (2012). Diversity of Tanaidacea (Crustacea: Peracarida) in the world's oceans – how far have we come? PLoS ONE 7(4): e33068. DOI: 10.1371/journal.pone.0033068