Fig. 1 from Miya et al.
It’s easy to be a new species, even easy to be a new genus. You got to be just a little different. Yes…yes…we are all unique and special snowflakes. But to get your own order, you got to be really different. If you are the taxonomist erecting a new order, you got have big cojones and strong evidence.
Currently there are about 70 odd fish orders. Scratch that…70 odd plus one. Miya et al. erect a new order based on both mitochondrial and nuclear DNA. The new order centers on the monotypic family (only one species in the family) Stylephoridae. The single species is Stylephorus chordatus, an extremely rare deep-sea fish affectionately referred to as Tube Eye. As you might guess, the DNA suggest that a new order Stylephoriformes is needed as the species as no close affinities with any other species. Genetic evidence suggest the “closest” relative is the Gadiformes (cod and allies) as opposed to the Lampridiformes previously suggested.
Tube-eye is a strange fish indeed. It possesses a pair of telescopic eyes that lie anteriorly when not feeding (B above). During feeding, the head is oriented up and back and the mouth is moved forward (C). The mouth cavity is balloonable and can greatly expand its size (38x). This creates negative pressure and provides suction for capturing prey.
Miya, M., Holcroft, N.I., Satoh, T.P., Yamaguchi, M., Nishida, M., Wiley, E. (2007). Mitochondrial genome and a nuclear gene indicate a novel phylogenetic position of deep-sea tube-eye fish (Stylephoridae). Ichthyological Research, 54(4), 323-332. DOI: 10.1007/s10228-007-0408-0