Hybrid enrichment of poorly preserved museum specimens refines homology hypotheses in a group of minute litter bugs (Hemiptera: Dipsocoromorpha: Schizopteridae)

• Published in: Systematic entomology Vol. 44; no. 4; pp. 985 - 995
• Main Authors: Knyshov, Alexander, Hoey‐Chamberlain, Rochelle, Weirauch, Christiane
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.10.2019; Wiley Subscription Services, Inc
• Subjects: Corixidea; Data collection; Deoxyribonucleic acid; DNA; Ethanol; Homology; Hypotheses; Mitochondria; Museums; Nucleotide sequence; Phylogeny; Schizopteridae; Taxonomic revision
• ISSN: 0307-6970; 1365-3113
• DOI: 10.1111/syen.12368

Although they are a valuable source of specimens, insect natural history collections continue to be under‐utilized in molecular systematics, mostly due to difficulties in obtaining DNA sequences. Old specimens or specimens stored under suboptimal conditions are intractable for traditional Sanger sequencing. In this study we use an inexpensive hybrid capture with in‐house generated baits to retrieve commonly utilized ribosomal and mitochondrial loci from old museum specimens and combine them with a Sanger‐generated dataset comprising recently collected material. We focus on the Corixidea genus group (Schizopteridae), which comprises rarely collected, small (1–2 mm) and primarily tropical insects of which only c. 10–20% of the species have been described. A molecular phylogeny is needed to resolve relationships and revise the genus‐level classification to correctly place the c. 150 yet to be described species. Applying this approach, we constructed a dataset, containing 101 taxa, 11 of which were preserved in low‐percentage ethanol, 48 are dry and point‐mounted, and 40 are > 20 years old at DNA extraction. The obtained data proved sufficient for reconstructing a well‐supported phylogeny with c. 50% of the predicted diversity, and for the oldest successfully sequenced specimen (95 years) to be unambiguously placed in that phylogeny. We confirmed monophyly of the Corixidea genus group, showed paraphyly of the genus Corixidea, and recovered nine well‐supported clades within the group. Ancestral character states of selected morphological features were inferred and used to re‐examine primary homology hypotheses and inform an upcoming taxonomic revision. We utilized a cost‐efficient hybrid enrichment approach to obtain sequence data for low‐quality samples, including specimens collected during the 1920s–1970s, and sampled half of the estimated species‐level diversity of the group. We confirmed monophyly of the Corixidea genus group, but refuted monophyly of the genus Corixidea and detected nine well‐supported clades, including four previously unknown lineages. Using ancestral state reconstruction of several putatively genus‐diagnostic features, we tested primary homology hypotheses and shaped the genus‐level classification of the group for an upcoming taxonomic revision.