Trigonopterus oblongus

Trigonopterus oblongus is a weevil found in Papua.

[1] It was notable as the first known instance of a biological screw joint.

[2] The weevils are just 4 millimetres (0.16 in) long and can fold their legs below their body.

The biological screw joint is just 0.5 millimetres (0.020 in) in size.

[3][4] This discovery was made by Alexander Riedel of the State Museum of Natural History Karlsruhe and by Thomas van de Kamp of the Karlsruhe Institute of Technology .

Diagram of the biological screw in the weevil Trigonopterus oblongus
The lateral aspect on thorax of the weevil Trigonopterus oblongus . In this genus , the metanepisternite is absent and the elytron touches the metaventrite (indicated).