A fish discovered solely in West African rivers and forest swimming pools can stick out a trunk-like snout to suck up meals or breathe air like a snorkel.

The hingemouth (Phractolaemus ansorgii) has what biologists name a deployable proboscis, a tubular construction folded into its head that may prolong upwards or downwards. The lips of the proboscis are lined with tooth-like buildings made out of keratin, which the fish makes use of to scrape up algae or different detritus.

Allyson Evans on the George Washington College in Washington DC and her colleagues used dissection, videography and CT scans to disclose the sophisticated building of its jaws.

Not like all different fish, whose jaw joint sits behind their mouth, the hingemouth’s jaw joint is on the entrance of its head. The decrease jaw is flipped backwards, pointing in the direction of the throat. The higher jaw, which is linked to the decrease jaw by a ligament, is a part of the proboscis. “You’ll be able to consider the higher jaws as being roughly suspended within the pores and skin of the proboscis,” says Evans. That is why the construction can prolong thus far out of the pinnacle.

The hingemouth affords “a novel mechanical resolution to a ubiquitous problem all fish face, which is easy methods to purchase meals inside a viscous, fluid medium”, says Evans.

She has additionally noticed the fish swimming as much as the floor and taking a gulp of air, utilizing the proboscis “like a snorkel”, she says. This could possibly be a helpful capacity in forest swimming pools the place oxygen ranges can run low.

Scientists aren’t positive how the hingemouth advanced, because the fossil proof is sparse. “The household that Phractolaemus belongs to, Kneriidae, is believed to be mid-Cretaceous in origin, however there’s merely no middleman kind discovered but within the fossil file,” says Evans.

“What’s most vital to me is that scientists stay curious in regards to the little freaks of the world,” she says.