Alexander Riedel

Many herbivorous beetles depend on plant cell wall-degrading enzymes (PCWDEs) to access the nutritious plant cell content. However, the evolution of PCWDEs in weevils, the most diverse lineage of herbivores, remains poorly understood. Using transcriptomic and genomic analyses of 45 weevil species spanning the majority of existing subfamilies, we identified a total of 13 different PCWDE families, revealing high variability between species. Interestingly, the PCWDE repertoires tracked dietary specialization, with convergent reductions in fungivorous taxa. Furthermore, PCWDE gene family dynamics were driven by both larval and adult specialized herbivory on different plant organs. Despite this complex evolutionary history, phylogenetic analyses place core PCWDE functionalities at the base of the Phytophaga (weevils, leaf beetles, and longhorn beetles) and reveal subsequent horizontal gene transfer (HGT) events from various donors during early Phytophaga diversification. These findings demonstrate that HGTs, gene duplications, and losses shaped PCWDE diversity and facilitated the ecological success of weevils.

Recent technological advances allow for the large-scale acquisition of genetic and morphological data: high-throughput sequencing has transformed the field of genomics while synchrotron X-ray microtomography enables rapid, noninvasive 3D imaging. However, integrating these approaches for the same specimens is challenging because X-rays can fragment DNA, and DNA extraction damages internal morphology, particularly relevant for small bodied organisms, such as insects. We systematically tested multiple extraction protocols and irradiation conditions across three model insect species. We irradiated more than 1,000 specimens under varying conditions and tested DNA quality through DNA barcoding and UCE sequencing. Our results demonstrate that high-quality DNA and high-resolution tomograms can be obtained from the same individuals, provided that the parameters are carefully optimized and rapid SR-μCT scanning precedes DNA extraction. In this respect, our findings establish practical guidelines for combining genomics and phenomics, paving the way for comprehensive integrative digitization of biodiversity.

Complex biomechanical innovations are often treated as discrete evolutionary breakthroughs, yet their diversification within large radiations remains poorly understood. Beetle leg joints provide a striking example: some weevils possess screw-like coxa-trochanteral articulations in which rotation and axial displacement are mechanically coupled, resembling engineered screw-and-nut mechanisms. Whether these joints represent isolated mechanical extremes, discrete adaptive types or part of a broader continuum of phenotypic variation has remained unknown. Here we combine synchrotron X-ray microtomography, landmark-free atlas-based morphometrics, quantitative functional morphology and phylogenetic comparative analyses to examine the mesocoxa-trochanteral joint in 68 species representing seven sampled family-level groups across early-diverging and derived weevil lineages. We show that screw joint evolution combines continuous variation in trochanteral shape with a restricted set of mechanically plausible joint-character combinations, rather than forming sharply separated morphological classes. True screw-and-nut joints are not confined to a distinct region of morphospace, indicating that overall form and mechanical configuration are not necessarily coupled. The occurrence of this configuration in the early diverging Caridae shows that it is not restricted to more derived families. Three-dimensional helix fitting revealed a mosaic geometry: winding angle showed the clearest relationship with the major shape axes (PC1-PC2), whereas axial pitch varied largely independently of shape, size and lineage. Together, these patterns show that screw joint components diversified with different degrees of evolutionary integration. These results recast the weevil screw joint from a singular biomechanical curiosity into a diversified evolutionary system. These patterns are consistent with diversification through differential modification and retention of components with differing degrees of structural constraint, rather than a single shift from simple to fully specialized designs.

The phylogeny of ‘broad-nosed weevils’ is explored with a data set of mitochondrial genomes of 130 species, representing 32 tribes. Phylogenetic analyses recovered a subdivision of Entiminae Schoenherr, 1823 into a ‘northern clade’ of mostly Palaearctic, Indomalayan, and African taxa and a ‘southern clade’ of Australian, Oceanian, and South American groups. Biogeographical reconstructions infer the origin of Entiminae in the Late Cretaceous in the Holarctic and a range expansion of the ‘southern clade’ from North America to South America. A group of genera with a ‘leptopiine’ type of rostrum are polyphyletic and subdivided based on zoogeographical regions: the Palaearctic and Nearctic genera remain in Byrsopagini Lacordaire, 1863; the Neotropical genera are placed in Strangaliodini Lacordaire, 1863; and the Indoaustralian genera are placed in Pantopoeini Lacordaire, 1863 (stat. nov.), which are given priority over Prypnini Lacordaire, 1863; the following names are junior synonyms of Pantopoeini: Elytrurini Marshall, 1956, syn. nov., Eupholini Günther, 1943, syn. nov, Leptopiini Oke, 1951, syn. nov., and Polycatini Marshall, 1956, syn. nov. Isopterina Morimoto & Kojima, 2001 is excluded from Celeuthetini Lacordaire, 1863 and promoted as tribe Isopterini (stat. nov.). The Sitoninae Gistel, 1848 (stat. nov.) are elevated to subfamily rank. Rhyncholobus Gahan, 1900 is transferred to Episomini Lacordaire, 1863. The Celeuthetini are sister group of Pachyrhynchini Schoenherr, 1826.

Type material of species belonging to the weevil tribe Celeuthetini Lacordaire, 1863 mainly from Sundaland, Sulawesi and the Lesser Sunda Islands was studied. Mitochondrial sequence data could be obtained for 27 old type specimens, providing important evidence on their systematic placement. Various taxonomic problems evident from molecular and morphological data are remedied. Nusasyntrophus Riedel gen. n., Parasyntrophus Riedel gen. n., and Apotomorhamphus geminus Riedel sp. n. are described. The following genera are junior synonyms of Piezonotus Schoenherr, 1834: Coptorhynchus Guérin-Méneville, 1841 (syn. n.), Picronotus Marshall, 1956 (syn. n.), Platyspartus Faust, 1897 (syn. n.). Colpomus Marshall, 1956 is a junior synonym of Enaptomias Faust, 1897 (syn. n.) and Aulacophrys Marshall, 1956 is a junior synonym of Apiezonotus Heller, 1941. Coptorhynchus ternatensis Guérin-Méneville, 1841 and Isomerinthus asper Pascoe, 1881 are transferred to Piezonotus Schoenherr, 1834: Piezonotus ternatensis (Guérin-Méneville, 1841) (comb.n.), Piezonotus asper (Pascoe, 1881) (comb.n.). New synonymies are proposed for the following species: Syntrophus carinicollis (Heller, 1914) = Syntrophus costicollis Marshall, 1956 (syn. n.); Syntrophus echinatus (Heller, 1900) = Syntrophus bipusulosus (Heller, 1940) (syn. n.). Apotomorrhamphus heteroglymmoides Günther, 1938 and A. femoratus Voss, 1940 are transferred to Heteroglymma Faust, 1897: Heteroglymma heteroglymmoides (Günther, 1938) comb.n., Heteroglymma femoratum (Voss, 1940) comb.n.; Heteroglymma bispinosa Heller, 1900 and Heteroglymma hoplocnemis Günther, 1938 are transferred to Atactoglymma Heller, 1900: A. bispinosum (Heller, 1900) comb. n., A. hoplocnemis (Günther, 1938) comb. n.; Heteroglymma carinuliferum Heller, 1914 is transferred to Javaulius Marshall, 1956: Javaulius carinulifer (Heller, 1914) comb.n.; Idiopsodes gitgitus (Heller, 1914), Idiopsodes radiatifrons (Heller, 1914), and Idiopsodes setosapex (Heller, 1914) are transferred to Parasyntrophus gen. n.: Parasyntrophus gitgitus (Heller, 1914) comb. n., P. radiatifrons (Heller, 1914) comb. n., P. setosapex (Heller, 1914) comb. n.; Phraotes nodifer Voss, 1940 is transferred to Bonthaina Heller: Bonthaina nodifera (Voss, 1940) comb. n. Piezonotus humeralis Heller, 1914 is transferred to Temnogastrus Marshall, 1956: Temnogastrus humeralis (Heller, 1914) comb. n.; Heteroglymma echinatum Heller, 1900 and Trigonops bipusulosa Heller, 1940 are transferred to Nusasyntrophus gen. n.: Nusasyntrophus echinatus (Heller, 1900) comb. n., Nusasyntrophus bipusulosus (Heller, 1940) comb. n. Nusasyntrophus echinatus virescens (Heller, 1914) and Tarunus wolterecki banggaiensis (Günther, 1938) are elevated to species status: N. virescens (Heller, 1914) stat. n., comb. n., Tarunus banggaiensis (Günther, 1938) stat. n. Apotomorrhamphus parcesetosus Voss, 1940 is resurrected from synonymy with A. splendens Faust, 1897. Bonthaina solitaria Heller, 1900 is designated type species of Bonthaina Heller, 1900. Lectotypes are designated for the following names: Apotomorhamphus sarasini Faust, Apotomorhamphus splendens Faust, 1897, Borneobius curvipes Marshall, 1956, Coptorrhynchus beccarii Pascoe, 1885, Coptorrhynchus wolterecki banggaiensis Günther, 1938, Coptorrhynchus wolterecki Günther, 1938, Heteroglymma bispinosum Heller, 1900, Heteroglymma carinicolle Heller, 1914, Heteroglymma carinuliferum Heller, 1914, Heteroglymma echinatum Heller, 1900, Heteroglymma echinatum virescens Heller, 1914, Heteroglymma setosum Marshall, 1925, Idiopsis gitgita Heller, 1914, Idiopsis radiatifrons Heller, 1914, Idiopsis setosapex Heller, 1914, Isomerinthus asper Pascoe, 1881, Javaulius rudis Marshall, 1956, Javaulius subvirens Marshall, 1956, Piezonotus suturalis Gyllenhal, 1834, Trigonops kombuisana Marshall, 1925, Trigonops renschi Heller, 1940, Trigonops tuberculata Faust, 1896, Piezonotus humeralis Heller, 1914, Piezonotus javanus Faust, 1896, Sphaeropterus gramineus Pascoe, 1881. Piezonotus suturalis Gyllenhal, 1834 is an endemic to the South Moluccas and its record for Java in the original description is erroneous. The genus Heteroglymma Faust, 1897 is redefined based on a ventral blunt tooth of the protibia. Some characters traditionally used for diagnosis of genera are briefly discussed. Apodemes attached to the body of the penis by flexible loops are discovered in the genera Apotomorhamphus Faust, 1897, Bonthaina Heller, 1900, and Nothes Marshall, 1956. A key to the genera of Celeuthetini from Sundaland, Sulawesi and the Lesser Sunda Islands is provided. Keys to the species are provided for the following genera: Apotomorhamphus Faust, 1897 (only species from Mt. Lompobattang), Bonthaina Heller, 1900, Javaulius Marshall, 1956, Nusasyntrophus gen. n., Parasyntrophus gen. n., Temnogastrus Marshall, 1956.

Ceutorhynchinae Gistel are a diverse weevil subfamily of almost worldwide distribution and considerable economic importance. Nevertheless, the classification of Ceutorhynchinae and their phylogenetic relationships are not yet fully resolved. Here, we sequenced the mitogenomes of 54 ceutorhynchine species. Phylogenetic analyses by maximum likelihood and Bayesian inference were performed on a dataset of 13 protein‐coding and two ribosomal genes. All analyses recovered three well supported clades A–C. A principal component analysis shows that codon usage differs considerably between these clades, indicating a compositional asymmetry in ceutorhynchine mitogenomes. This increased the challenge of resolving the early relationships among the three clades. The resolution of the later diversification was more robust, and the resulting topologies were largely compatible with each other and with the current taxonomic classification. Exceptions are the genera Micrelus Thomson, which is transferred from the tribe Ceutorhynchini to Egriini Pajni and Kohli (new position) and Amalus Schoenherr, which is transferred to Phytobiini Gistel (new position). Amalini Wagner 1936 is a junior synonym of Phytobiini Gistel 1848 (syn. n.). Coeliodini Lacordaire (new status), a tribe previously regarded as junior synonym of Ceutorhynchini, is re‐established. Our analyses also clarified the difficult assignments of taxa to the tribes Scleropterini Schultze and Phytobiini. All taxa with the ability to jump as adult beetles belong to clade B, which comprises the tribes Cnemogonini Colonnelli, Hypurini Schultze, Mecysmoderini Wagner and Phytobiini. With dense taxon sampling and appropriate analytical methods, mitogenome data provide a phylogeny well suited to improve the traditional classification of this neglected and species‐rich taxon.

The geologically‐complex Indo–Australian–Melanesian archipelago (IAMA) hosts extraordinarily high levels of species richness and endemism and has long served as a natural laboratory for studying biogeography and evolution. Nonetheless, its geological history and the provenance and evolution of its biodiversity remain poorly understood. Here, we provide a geological scenario for the IAMA informed by a time‐calibrated molecular phylogeny of 1006 species of Trigonopterus weevils – an exceptionally diverse radiation of regionally‐endemic flightless beetles. Moreover, we performed a statistical biogeographic analysis and examined timing and patterns in the accumulation of lineages residing in a priori‐defined geographic units comprising the IAMA. We estimate that Trigonopterus originated in Australia during the early Paleogene. Subsequent rapid diversification in the area of the present‐day Papuan Peninsula suggests the presence of proto‐Papuan islands by the middle Eocene; the New Guinea North Coast Ranges were colonized in the late Eocene, followed by the New Guinea Highlands and the Bird's Head Peninsula. We inferred the presence of terrestrial habitat in the North Moluccas and Sulawesi in the late Oligocene and the subsequent rapid colonization of Sundaland and the Lesser Sunda Islands. New Caledonia and Samoa were colonized from the Papuan Peninsula, and their faunas also diverged in the late Oligocene. These biota‐informed time estimates are compatible with geological data from the region and shed new light on IAMA paleogeography, even where geological evidence has been lost to erosion. Beetle evolution thus appears to have closely tracked the geological evolution of the IAMA, revealing a uniquely well‐resolved view of regional biogeography.

The DNA of Trigonopterus specimens from the Sundaland region stored between ten and 32 years in museums could be used for next-generation sequencing. The availability of their cox1 sequence allowed the description of the following nine new species: Trigonopterus grimmisp. nov., T. johorensissp. nov., T. lambirensissp. nov., T. linauensissp. nov., T. microreticulatus Riedel, Trnka & Wahab sp. nov., T. mulensissp. nov., T. sarawakensissp. nov., T. siamensissp. nov., and T. singaporensissp. nov. The alternative original spelling of the name T. tounensis Narakusumo & Riedel is chosen to prevail over T. tounaensis Narakusumo & Riedel. The new species represent the first country records of Trigonopterus for Brunei, Singapore, and Thailand. Thus, the genus´ known area of distribution in the Sundaland region is significantly extended. A key and a catalogue are provided to the Trigonopterus species from Borneo, W-Malaysia, Singapore, and Thailand.

Here we present 28 new species of Trigonopterus from Central Sulawesi, mostly from Mt Dako and Mt Pompangeo: Trigonopterus acutus sp. nov., T. ancora sp. nov., T. arcanus sp. nov., T. corona sp. nov., T. dakoensis sp. nov., T. daun sp. nov., T. ewok sp. nov., T. gundala sp. nov., T. hoppla sp. nov., T. kakimerah sp. nov., T. katopasensis sp. nov., T. matakensis sp. nov., T. moduai sp. nov., T. mons sp. nov., T. paramoduai sp. nov. T. pomberimbensis sp. nov., T. pompangeensis sp. nov., T. puspoi sp. nov., T. rosichoni sp. nov., T. rubidus sp. nov., T. sarinoi sp. nov., T. sutrisnoi sp. nov., T. tanah sp. nov., T. tejokusumoi sp. nov., T. toboliensis sp. nov., T. tolitoliensis sp. nov., T. tounaensis sp. nov., T. unyil sp. nov. This fills important areas of distribution and brings the number of Trigonopterus species recorded from Sulawesi to 132.

Mitochondrial genomes of twelve species of Trigonopterus weevils are presented, ten of them complete. We describe their gene order and molecular features and test their potential for reconstructing the phylogeny of this hyperdiverse genus comprising > 1,000 species. The complete mitochondrial genomes examined herein ranged from 16,501 bp to 21,007 bp in length, with an average AT content of 64.2% to 69.7%. Composition frequencies and skews were generally lower across species for atp6, cox1-3, and cob genes, while atp8 and genes coded on the minus strand showed much higher divergence at both nucleotide and amino acid levels. Most variation within genes was found at the codon level with high variation at third codon sites across species, and with lesser degree at the coding strand level. Two large non-coding regions were found, CR1 (between rrnS and trnI genes) and CR2 (between trnI and trnQ), but both with large variability in length; this peculiar structure of the non-coding region may be a derived character of Curculionoidea. The nad1 and cob genes exhibited an unusually high interspecific length variation of up to 24 bp near the 3′ end. This pattern was probably caused by a single evolutionary event since both genes are only separated by trnS2 and length variation is extremely rare in mitochondrial protein coding genes. We inferred phylogenetic trees using protein coding gene sequences implementing both maximum likelihood and Bayesian approaches, each for both nucleotide and amino acid sequences. While some clades could be retrieved from all reconstructions with high confidence, there were also a number of differences and relatively low support for some basal nodes. The best partition scheme of the 13 protein coding sequences obtained by IQTREE suggested that phylogenetic signal is more accurate by splitting sequence variation at the codon site level as well as coding strand, rather than at the gene level. This result corroborated the different patterns found in Trigonopterus regarding to A+T frequencies and AT and GC skews that also greatly diverge at the codon site and coding strand levels.