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Submitted by editor on 3 December 2023. Get the paper!
Determine 1. 100 species of the genus Trigonopterus. Credit score: Alexander Riedel.
Abstract:
The islands of Indonesia and the West Pacific host a rare variety of life, together with greater than 1000 species of flightless Trigonopterus beetles. Utilizing statistical analyses of DNA sequences from 1006 Trigonopterus species, we confirmed that beetle evolution has tracked the formation of terrestrial habitats in Indonesia and the West Pacific over the previous 40 million years, revealing new insights into the advanced geological historical past of this tropical area and the origins and evolution of its distinctive and threatened biodiversity. The research was printed open entry within the journal Ecography.
Essential physique:
The world´s largest tropical archipelago, comprising Malaysia, Indonesia, the Philippines, Papua New Guinea, and different island nations of the West Pacific, is well-known for its extraordinary biodiversity and complicated geological historical past. Alfred Russel Wallace famously studied the fauna of this area, leading to his unbiased discovery of the idea of evolution and his foundational contributions to biogeography, a self-discipline that explores the geographic distributions of organisms and the elements shaping such patterns. Wallace largely centered on conspicuous teams of animals, reminiscent of birds and butterflies, as was customary on the time. Nevertheless, he additionally collected beetles, together with a couple of tiny weevils from the exceptionally numerous genus Trigonopterus.
Determine 2. Schematic evolutionary historical past of 1006 Trigonopterus species. Credit score: Harald Letsch.
Trigonopterus beetles are wingless and, thus, flightless, confining most species to comparatively small geographic areas. Alexander Riedel (Pure Historical past Museum Karlsruhe) has undertaken in depth area research of Trigonopterus throughout their geographic vary in Southeast Asia, Australia, and the West Pacific, documenting a whole lot of undescribed species. Based on Riedel: “Having named greater than 370 new species and with many further new species at hand, we determined it was time to have a look at the massive image and look at the evolutionary historical past of all Trigonopterus species.”
Riedel´s co-worker Harald Letsch (College of Vienna) generated a time-calibrated phylogeny (genealogical tree of Trigonopterus species), based mostly on DNA knowledge from 1006 species. This isn’t solely one of many largest phylogenies ever produced for a single genus of animals but in addition reveals new insights into the advanced geological historical past of Indonesia and the West Pacific and the origins and evolution of its distinctive and threatened biodiversity.
Notably, Letsch et al.’s work confirmed that Trigonopterus weevils skilled comparatively few dispersal occasions of their 40 million-year historical past, indicating that their phylogenetic tree ought to include robust signatures of regional geological historical past, together with the formation and erosion of islands and their topographic options. Geographic boundaries to dispersal and geographic isolation are likely to trigger populations of poorly dispersing species, like flightless Trigonopterus beetles, to diverge and type completely different species. In an archipelagic setting, will increase in charges of diversification recommend the presence and doable will increase within the extent or topographic complexity of liveable land, no matter whether or not that land nonetheless exists. Thus, organic knowledge like these reported on weevils can present data on the geological historical past of a panorama, even the place bodily proof has been misplaced to erosion.
Determine 3. Schematic illustration of the dispersal of Trigonopterus weevils out of northern Australia. Credit score: Harald Letsch.
Maps of Indonesia and the West Pacific islands over the past 40 million years reconstructed by Letsch et al. based mostly on the evolutionary historical past of Trigonopterus beetles present intriguing new insights into the enigmatic geological historical past of the area. For instance, they recommend that the Papuan Peninsula of New Guinea was emergent by ca. 40 million years in the past, sooner than some present hypotheses. Moreover, the diversification of Trigonopterus on the Samoan Islands is indicated to have began ca 23 million years in the past, suggesting the existence of eroded and now sunken islands far to the west of the present island chain. Thus, Letsch et al. notably show that their method to reconstructing regional geological historical past might be of nice worth to geology, emancipating the self-discipline of biogeography from its position as a internet receiver of knowledge to a contributor of helpful knowledge to associated disciplines.
Determine 4. Virgin rainforest, the habitat of Trigonopterus weevils, right here on the island of Biak. Credit score: Alexander Riedel.
Unique Sources:
Letsch, H., Balke, M., Kusy, D., McKenna, D.D., Narakusumo, R.D., Sagata, Ok., Toussaint, E.F.A., White, L.T., Riedel, A. 2023. Beetle evolution illuminates the geological historical past of the world’s most numerous tropical archipelago. Ecography 2023: e06898.
Contacts:
Alexander Riedel (State Museum of Pure Historical past Karlsruhe, Germany)
Electronic mail: riedel [at] smnk [dot] de
Harald Letsch (College of Vienna, Austria)
Electronic mail: harald [dot] letsch [at] univie [dot] ac [dot] at
Duane D. McKenna (College of Memphis, USA)
Electronic mail: dmckenna [at] memphis [dot] edu
Classes:
Basic
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