Species diversity revealed in Sigmella Hebard, 1929 (Blattodea, ectobiidae) based on morphology and four molecular species delimitation methods.

Meng Li,Rong Chen,Qiongyao Zhao,Yanli Che,Tao Peng,Zongqing Wang,Wenbo Deng,Jiajun He,Feng Zhang

doi:10.1371/journal.pone.0232821

Meng Li, Rong Chen + Show 7 more

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https://doi.org/10.1371/journal.pone.0232821

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Journal: PloS one	Publication Date: Jun 10, 2020
Citations: 5	License type: CC BY 4.0

Affiliation: Southwest University

Abstract

Cockroaches are one of the major decomposers involved in biogeochemical cycles. Cockroaches have an amazing amount of diversity, but most of them remain unknown due to the shortage of the trained taxonomists and the limitations of morphology-based identification. We obtained 49 COI sequences (including 42 novel sequences) and 32 novel 28S sequences for 5 Sigmella morphospecies collected from 11 localities. Three are new to science: Sigmella digitalis sp. nov., Sigmella exserta sp. nov. and Sigmella normalis sp. nov. Based on four species delimitation methods (ABGD, GMYC, BINs and bPTP), a total of 6 molecular operational taxonomic units (MOTUs) were recovered for 5 morphospecies. These were then confirmed by tree building methods using COI and combined data (COI and 28S). We detected more than one MOTU in the morphospecies S. digitalis sp. nov., which can indicate genetic diversity. Detailed morphological evidence for each MOTU is provided to confirm these slight variations and we conclude that natural barriers are likely the main cause of genetic diversity.

Highlights

Apart from a few species of Blattodea such as Periplaneta americana, Periplaneta fuliginosa and Blattella germanica that are domestic pests, most cockroaches play a major role as decomposers in biogeochemical cycles [1]
S. digitalis sp. nov., S. exserta sp. nov. and S. normalis sp. nov. are established, and two known species, S. puchihlungi and S. schenklingi biguttata are well identified according to only morphological characters including male genitalia (Figs 3A–3H and S4A–S4R)
We examined the utility of using DNA barcode data in species identification and the assessing the genetic diversity in 5 morphospecies of Sigmella cockroaches recovered from our General Mixed Yule-coalescent (GMYC), Barcode Index Numbers [19] (BINs), bPTP and Automatic Barcode Gap Discovery (ABGD) analysis

Summary

Introduction

Apart from a few species of Blattodea such as Periplaneta americana, Periplaneta fuliginosa and Blattella germanica that are domestic pests, most cockroaches play a major role as decomposers in biogeochemical cycles [1]. Many species remain unknown or misidentified because of different juvenile morphology, sexual dimorphism and polymorphism [1, 3, 4] which cannot be resolved by only applying morphological characters. It is very challenging if only morphology-based identification is applied. Individuals of related Sigmella species have a highly conserved external morphology, but exhibit slight variations in the shape of the male genitalia, which comprises an impediment to judging the interspecific differences (Li M & Wang ZQ, personal observation).

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