Where Taxonomy Based on Subtle Morphological Differences Is Perfectly Mirrored by Huge Genetic Distances: DNA Barcoding in Protura (Hexapoda)

Abstract

BackgroundProtura is a group of tiny, primarily wingless hexapods living in soil habitats. Presently about 800 valid species are known. Diagnostic characters are very inconspicuous and difficult to recognize. Therefore taxonomic work constitutes an extraordinary challenge which requires special skills and experience. Aim of the present pilot project was to examine if DNA barcoding can be a useful additional approach for delimiting and determining proturan species.Methodology and Principal FindingsThe study was performed on 103 proturan specimens, collected primarily in Austria, with additional samples from China and Japan. The animals were examined with two markers, the DNA barcoding region of the mitochondrial COI gene and a fragment of the nuclear 28S rDNA (Divergent Domain 2 and 3). Due to the minuteness of Protura a modified non-destructive DNA-extraction method was used which enables subsequent species determination. Both markers separated the examined proturans into highly congruent well supported clusters. Species determination was performed without knowledge of the results of the molecular analyses. The investigated specimens comprise a total of 16 species belonging to 8 genera. Remarkably, morphological determination in all species exactly mirrors molecular clusters. The investigation revealed unusually huge genetic COI distances among the investigated proturans, both maximal intraspecific distances (0–21.3%), as well as maximal congeneric interspecifical distances (up to 44.7%).ConclusionsThe study clearly demonstrates that the tricky morphological taxonomy in Protura has a solid biological background and that accurate species delimitation is possible using both markers, COI and 28S rDNA. The fact that both molecular and morphological analyses can be performed on the same individual will be of great importance for the description of new species and offers a valuable new tool for biological and ecological studies, in which proturans have generally remained undetermined at species level.

Paracerella Imadaté in China: the description of a new species and the analysis of genetic differences between populations (Protura, Acerentomata, Nipponentomidae)

“…However, the intraspecific genetic distances of Paracerella sinensis sp. n. are very high (up to 12.54%), which is in accord with the previous studies on some other proturan species: up to 21.3% in eight individuals of Ionescuellum haybachae from two Austria populations (Resch et al 2014), and up to 31.98% separating 21 representatives of Acerentomon italicum in three Italian populations from an Austrian population (Galli et al 2015). The similar situation was also found in another basal hexapod group–Collembola: six collembolan species sampled from various locations worldwide with high intraspecific variation for COI from 11.33% to 21.47% (Porco et al 2012).…”

Limnephilid taxa revised by speciation traits: Rhadicoleptus, Isogamus, Melampophylax genera, Chaetopteryx rugulosa, Psilopteryx psorosa species groups, Drusus bolivari, Annitella kosciuszkii species complexes (Trichoptera: Limnephilidae)

“…Animal groups with limited morphological structures, such as the Lampetra genus, that possesses so few of the morphological characters (Mateus et al 2013) or Protura where the taxonomy is based on subtle morphological differences, routine sequence data or even barcoding represent valuable source of information and mirrored by significant genetic distances (Resh et al 2014). The population-genetic studies have been rather productive in the last decades based on the invention of polymerase chain reaction technology and on applying mitochondrial and nuclear neutral markers.…”

Redescription and review of the most abundant conehead in Italy:Acerentomon italicumNosek, 1969 (Protura: Acerentomidae)

“…The geological substratum has been recorded only in a (Table V). Analysing them together with the sequence from a population in Vienna (Resch et al 2014) revealed big distances separating the Italian from the Austrian populations of Acerentomon italicum (maximum intraspecific pairwise distance: 31.98%).…”