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''Trigonopterus'' is a genus of flightless weevils placed in the Cryptorhynchinae of Curculionidae. It is distributed in the area between Sumatra, Samoa, the Philippines, and New Caledonia. About 90 species had been formally described until March 2013, when a single paper more than doubled this number, agreeing with previous studies and a systematic barcoding study that many more species have yet to be described. The center of its diversity appears to be New Guinea where 51 or more species can be found in a single locality. Many of them are very similar to each other, but male genital characters and DNA barcoding allow a safe identification. The genus can be diagnosed among wingless cryptorhynchine weevils by the absence of a metanepisternum and by a synapomorphic structure of the tarsus with minute claws and a deeply incavated articulation of tarsomere 4. The metathoracic spiracle located externally at the side of the metaventrite is a unique feature and may ensure sufficient respiration during thanatosis 〔 *, , , , , & 2015: Comparative thorax morphology of death-feigning flightless cryptorhynchine weevils (Coleoptera: Curculionidae) based on 3D reconstructions. (''Arthropod Structure & Development'' ) 44: 509–523. 〕. ''Trigonopterus'' species inhabit primary tropical forests, both on foliage and edaphic in the litter layer. They have a marked tendency to endemism with many species only known from a single locality. Their primary defence against predators is apparent death or thanatosis. An animated 3D model of a ''Trigonopterus'' weevil reveals a number of mechanisms to maintain a stable defensive position. ==''Trigonopterus oblongus''== The species ''Trigonopterus oblongus'' (Pascoe, 1885) is found in Papua. It became notable in July 2011 when examination of the anatomy of the weevil revealed the first instance of a biological screw joint. ''T. oblongus'' is just long and can fold their legs below their body. The biological screw joint is just in size. 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 .〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Trigonopterus」の詳細全文を読む スポンサード リンク
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