No abstract

The beetle suborder Adephaga has been the subject of many phylogenetic reconstructions utilizing a variety of data sources and inference methods. However, no strong consensus has yet emerged on the relationships among major adephagan lineages. Ultraconserved elements (UCEs) have proved useful for inferring difficult or unresolved phylogenies at varying timescales in vertebrates, arachnids and Hymenoptera. Recently, a UCE bait set was developed for Coleoptera using polyphagan genomes and a member of the order Strepsiptera as an outgroup. Here, we examine the utility of UCEs for reconstructing the phylogeny of adephagan families, in the first in vitro application a UCE bait set in Coleoptera. Our final dataset included 305 UCE loci for 18 representatives of all adephagan families except Aspidytidae, and two polyphagan outgroups, with a total concatenated length of 83 547 bp. We inferred trees using maximum likelihood analyses of the concatenated UCE alignment and coalescent species tree methods (astral ii, ASTRID, svdquartets). Although the coalescent species tree methods had poor resolution and weak support, concatenated analyses produced well-resolved, highly supported trees. Hydradephaga was recovered as paraphyletic, with Gyrinidae sister to Geadephaga and all other adephagans. Haliplidae was recovered as sister to Dytiscoidea, with Hygrobiidae and Amphizoidae successive sisters to Dytiscidae. Finally, Noteridae was recovered as monophyletic and sister to Meruidae. Given the success of UCE data for resolving phylogenetic relationships within Adephaga, we suggest the potential for further resolution of relationships within Adephaga using UCEs with improved taxon sampling, and by developing Adephaga-specific probes.

Adephaga is the second largest suborder of beetles (Coleoptera) and they serve as important arthropod predators in both aquatic and terrestrial ecosystems. The suborder is divided into Geadephaga comprising terrestrial families and Hydradephaga for aquatic lineages. Despite numerous studies, phylogenetic relationships among the adephagan families and monophyly of the Hydradephaga itself remain in question.Here we conduct a comprehensive phylogenomic analysis of the suborder using ultraconserved elements (UCEs). This study presents the first in vitro test of a newly developed UCE probe set customized for use within Adephaga that includes both probes tailored specifically for the suborder, alongside generalized Coleoptera probes previously found to work in adephagan taxa. We assess the utility of the entire probe set, as well as comparing the tailored and generalized probes alone for reconstructing evolutionary relationships. Our analyses recovered strong support for the paraphyly of Hydradephaga with whirligig beetles (Gyrinidae) placed as sister to all other adephagan families. Geadephaga was strongly supported as monophyletic and placed sister to a clade composed of Haliplidae + Dytiscoidea. Monophyly of Dytiscoidea was strongly supported with relationships among the dytiscoid families resolved and strongly supported. Relationships among the subfamilies of Dytiscidae were strongly supported but largely incongruent with prior phylogenetic estimates for the family. The results of our UCE probe comparison showed that tailored probes alone outperformed generalized probes alone, as well as the full combined probe set (containing both types of probes), under decreased taxon sampling. When taxon sampling was increased, the full combined probe set outperformed both tailored probes and generalized probes alone. This study provides further evidence that UCE probe sets customized for a focal group result in a greater number of recovered loci and substantially improve phylogenomic analysis.

No abstract

Notomicrinae (Coleoptera: Noteridae) is a subfamily of minute and ecologically diverse aquatic beetles distributed across the Southeast Asia, Oceania, and the Americas. We investigate the evolution of Notomicrinae and construct the first species-level phylogeny within Noteridae using five nuclear and mitochondrial gene fragments. We focus on the genus Notomicrus Sharp (Coleoptera: Noteridae), sampling 13 of the 17 known Notomicrus species and an additional 11 putative undescribed species. We also include Phreatodytes haibaraensis Uéno (Coleoptera: Noteridae). Datasets are analyzed in Maximum Likelihood and Bayesian frameworks. With these, we 1) estimate divergence times among notomicrine taxa and reconstruct the biogeographical history of the group, particularly testing the hypothesis of Gondwanan vicariance between Old World and New World Notomicrus; 2) additionally, we assess ecological plasticity within Notomicrinae in the context of the phylogeny; and 3) finally, we test the monophyly of tentative species groups within Notomicrus and place putative new taxa. We recover a monophyletic Notomicrinae, with Phreatodytes sister to Notomicrus. We estimate the crown age of Notomicrinae to be ca. 110 Mya. The crown age of Notomicrus is recovered as ca. 75 Mya, there diverging into reciprocally monophyletic Old and New World clades, suggesting Gondwanan vicariance. Our phylogenetic estimate indicates a strong degree of ecological plasticity within Notomicrinae, with habitat switching occurring in recently diverging taxa. Finally, we recover five main species groups in Notomicrus, one Old World, Four New World, with tentative affirmation of the placement of undescribed species.

Beetles are arguably the most diverse group of animals on Earth with over 400 000 described species. Yet the timing of main diversification events among these insects remains debated. The use of phylogenomic data generated using next‐generation sequencing recently resolved most recalcitrant phylogenetic relationships across Coleoptera. However, limited taxon sampling for some major clades still prevents the use of important fossil calibrations that could provide more accurate estimates of the timing of lineage diversification events among beetles. Here, we present a new fossil‐based dated framework with a focus on the suborder Adephaga. We rely on an integrative phylogenomic approach using a combination of genomic, ultraconserved element and RNAseq transcriptomic datasets, further revealing the prevalent exonic nature of ultraconserved elements in Coleoptera. We infer a robust phylogenomic tree under various optimality criteria and analytical conditions. Our preferred phylogenetic reconstruction is consistent with those of previous phylogenomic studies in recovering the paraphyly of ‘Hydradephaga’, Gyrinidae as sister to all other Adephaga, the monophyly of Geadephaga and Haliplidae as sister to a monophyletic Dytiscoidea. We further recover strong support for paraphyly of Aspidytidae and the placement of Hygrobiidae as part of a clade comprising Aspidytes, Ribera, Beutel, Balke & Vogler, Sinaspidytes Balke, Beutel & Ribera and Amphizoidae. Using 23 carefully chosen fossil calibrations across Coleoptera, we infer the origin of modern beetles ca. 317 Ma in the mid‐Carboniferous, the divergence between Archostemata and Adephaga ca. 296 Ma in the early Permian, and the crown of Adephaga in the end‐Permian ca. 255 Ma. Importantly, our analyses provide more precise estimates of divergence times for internal splits within Adephaga, including ground beetles, tiger beetles and aquatic adephagan lineages. These results represent a major step forward in our understanding of beetle diversification and will serve as a fundamental framework to unravel the evolutionary history of many clades within Adephaga.

No abstract

Notomicrus petrareptans sp. n. is described from an inselberg seepage in southwestern Suriname. This species is diagnosable by a combination of its weakly punctate elytra, respective shapes of the pro- and mesotarsal claws (males), and long and slender median lobe of the aedeagus. This is the first member of the subfamily Notomicrinae to be described from hygropetric seep habitats and only the second known seep-dwelling species of the family Noteridae. Diagnostic characters are illustrated and habitat images are provided.