Bichirs are a family of ray-finned fish that are rather unusual looking in appearance. For example, they have a series of dorsal finlets rather than a single dorsal fin. Similarly, they have thick, rhombus-shaped ganoid scales. On top of this, bichirs even have jaws that are more reminiscent of those of tetrapods than those of teleosts. Combined, this means that these fish can seem very archaic.
Having said that, the bichirs’ most notable feature might be their lungs. They are capable of breathing through their mouths. However, bichirs have the extra option of breathing through a pair of spiracles mounted on top of their heads. Sometimes, they do so because they are in poorly oxygenated waters. Other times, they do so because they can’t incline their bodies in the right way for them to breathe through their mouths. Besides this, it is interesting to note that bichirs are still quite different from most lungfish and tetrapods in that their lungs are smooth rather than alveolar.
Moving on, there are two genera of bichirs that can be found in the present time. One genus has a single representative, which would be the reedfish. Meanwhile, the other genus has a number of living species, which are called various kinds of bichirs.
Once upon a time, these fish were considered to be a potential link between fish and amphibians. However, studying them was complicated by the fact that they resided in African swamps, which were home to malaria-carrying mosquitoes.
Eventually, two men named Nathan Harrington and John Samuel Budgett managed to produce enough material in the late 19th century and early 20th century for scientists to disprove this line of speculation. Unfortunately, Harrington died on his second trip, while Budgett succeeded on his fifth trip before dying of blackwater fever just a short while after returning to England.