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 lengthen 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 difficult building of its jaws.

In contrast to 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 direction of the throat. The higher jaw, which is linked to the decrease jaw by a ligament, is a part of the proboscis. “You possibly can consider the higher jaws as being roughly suspended within the pores and skin of the proboscis,” says Evans. For this reason the construction can lengthen up to now out of the top.

The hingemouth gives “a novel mechanical resolution to a ubiquitous problem all fish face, which is the way 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 capability in forest swimming pools the place oxygen ranges can run low.

Scientists aren’t positive how the hingemouth developed, 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 type discovered but within the fossil report,” says Evans.

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