Integrative species delimitation based on COI, ITS, and morphological evidence illustrates a unique evolutionary history of the genus Paracercion (Odonata: Coenagrionidae)

Abstract

Paracercion are common ‘blue and black’ colored damselflies. We explore the species boundaries of Paracercion (Odonata: Coenagrionidae) using ABGD, bPTP, GMYC and Distance-based clustering. We finally got the molecular data of all nine species of Paracercion. P. hieroglyphicum and P. melanotum were combined into one putative species based on cytochrome c oxidase I (COI). However, they were separated into two putative species based on the nuclear segment including ITS1-5.8S-ITS2 (ITS). This suggests the introgression of mtDNA in Paracercion. Paracercion barbatum and Paracercion melanotum can be separated into two species based on COI, whereas they were combined into one putative species based on ITS, which suggests a hybridization event between them. The lower interspecific divergence (COI: 0.49%) between P. barbatum and Paracercion v-nigrum indicates a recent speciation event in Paracercion. Paracercion sieboldii and P. v-nigrum can be separated into two putative species based on COI, while they were frequently merged into the same putative species based on ITS. This can be explained by incomplete lineage sorting in nDNA. Besides, P. pendulum and P. malayanum were synonymized as junior synonyms of P. melanotum. P. luzonicum was confirmed not to belong to Paracercion. The possibility of introgression, hybridization, recent speciation and incomplete lineage sorting makes species delimitation, based on molecular data, difficult and complicates understanding of the evolutionary history of Paracercion. The discordance in COI and ITS also indicates the value of using markers from different sources in species delimitation studies.

Phylogeny and phylogeography of Diestramima cave crickets (Orthoptera: Rhaphidophoridae): speciation driven by multiple dispersal and vicariance events

“…The number of MOTUs generated from all methods was far more than the morphological species, especially the MOTUs generated from bPTP and GMYC. This may be due to the high rates of false positives of the PTP and GMYC methods (Luo et al, 2018;Song et al, 2018;Hofmann et al, 2019;Zhou et al, 2019;Zhang et al, 2021). Five species (D. beybienkoi, D. subtilis, D. conica, D. excavata and D. taiwanensis) were divided into two to eight MOTUs by all four species delimitation methods.…”

“…Cave crickets, with poor dispersal ability, may accumulate genetic differentiation among different geographic populations more rapidly than significant morphological characteristics. In addition, as mentioned above, species delimitation methods may not accurately delimit species boundaries or may give conflicting results (Li et al, 2021a(Li et al, , 2021bZhang et al, 2021). Thus, inferences drawn from molecular species delimitation studies should be conservative (Carstens et al, 2013).…”

“…Thus, inferences drawn from molecular species delimitation studies should be conservative (Carstens et al, 2013). Conclusions should be drawn by integrating molecular data and morphological characteristics, and molecular analyses should include multiple methods and multiple loci (Zhang et al, 2021). Because of the lack of morphological resolution and support, populations from different geographic distributions that formed distinct MOTUs are, therefore, still treated as a single species.…”

DNA Barcoding and Phylogeny of Acari Species Based on ITS and COI Markers

“…However, the lack of records covering Acari species or not covering their "barcode" region (corresponding to the 3' region of COI gene or ITS) ( [4,16,33,37,57]; and references herein) highlights the need supplied in this work by increasing the number of sequences belonging to agriculture important Acari species, also being able to fit some gaps missing in phylogenies, which is a hot topic in Acarology nowadays [13,54,[58][59][60][61]. However, species delimitation based solely on molecular data is still under controversy, with some groups asking for integrative methods that take into account nucleotide distances, phylogenetic closeness, and morphological evidence, placing efforts to develop analysis tools for this integrative species delimitation [62][63][64][65][66][67][68], none of them being focused on Acari species.…”

Phylogeny and Integrative Taxonomy of the Genera Gymnaetoides and Pseudotachycines (Orthoptera: Rhaphidophoridae)

“…However, no distinct difference is found between different MOTUs. The more MOTUs generated by the PTP and GMYC methods might be due to the high rates of false positives of them [ 47 , 48 , 49 , 50 , 51 ].…”