Cryptic diversity: Two morphologically similar species of invasive apple snail in Peninsular Malaysia

Abstract

Invasive snails in the genus Pomacea have spread across Southeast Asia including Peninsular Malaysia. Their effects on natural and agricultural wetlands are appreciable, but species-specific effects are less clear because of morphological similarity among the species. Our objective was to establish diagnostic characteristics of Pomacea species in Malaysia using genetic and morphological criteria. The mitochondrial COI gene of 52 adult snails from eight localities in Peninsular Malaysia was amplified, sequenced, and analysed to verify species and phylogenetic relationships. Shells were compared using geometric morphometric and covariance analyses. Two monophyletic taxa, P. canaliculata and P. maculata, occurred in our samples. The mean ratio of shell height: aperture height (P = 0.042) and shell height: shell width (P = 0.007) was smaller in P. maculata. P. maculata co-occurred with P. canaliculata in five localities, but samples from three localities contained only P. canaliculata. This study is the first to confirm the presence of two of the most invasive species of Pomacea in Peninsular Malaysia using a molecular technique. P. canaliculata appears to be the more widespread species. Despite statistical differences, both quantitative and qualitative morphological characteristics demonstrated much interspecific overlap and intraspecific variability; thus, shell morphology alone cannot reliably verify species identity. Molecular techniques for distinguishing between these two highly invasive Pomacea species are needed to understand their specific ecological niches and to develop effective protocols for their management.

The efficiency of universal mitochondrial DNA barcodes for species discrimination of Pomacea canaliculata and Pomacea maculata

“…The phylogeny reconstructed with both barcoding markers grouped each species in monophyly, which is a typical indication of successful barcoding (Hebert et al, 2004;Meier et al, 2006). The species discrimination provided by the barcoding markers confirmed previous morphological and molecular COI data of both P. canaliculata and P. maculata as two widespread species of non-native apple snails in Malaysia (Arfan et al, 2014;Arfan et al, 2016;Rama Rao et al, 2018). Both COI and 16S rDNA phylogenetic trees possessed similar topologies confirming clear phylogenetic signals for discriminating between these two species of apple snails (Figs.…”

“…Additionally, the putative maternal and haploid mode of mitochondrial inheritance provides a single evolutionary lineage thereby reducing complexities of genetic recombination which can complicate phylogenetic reconstruction for diploid loci (Ladoukakis & Zouros, 2017). A portion of the cytochrome c oxidase subunit I (COI) gene, the universal DNA barcoding marker (Hebert et al, 2004;Savolainen et al, 2005;Ratnasingham & Hebert, 2007), has successfully delineated P. canaliculata from P. maculata from native (Brazil and Argentina) and invaded (China, Japan, USA and Malaysia) regions (Hayes, Cowie & Thiengo, 2009;Matsukura et al, 2008;Rama Rao et al, 2018). Furthermore, the COI barcoding region provided successful species delineation and it was concordant with morphological-based assessments (Hayes et al, 2012), which serves as a prerequisite for the reliable use of DNA barcodes.…”

A high-throughput amplicon sequencing approach for population-wide species diversity and composition survey

“…Detection of co-amplified pseudogenes/NUMTs demonstrated the complexity of the Bemisia genome (Chen et al, 2016; Xie et al, 2017; Xie et al, 2018). HTS-amplicon analyses also shed light on the unexpected co-amplification of non-target whitefly genomic regions, as well as fungal, bacterial symbionts, and parasitoids genomic regions, and highlighted the complexity of trophic interactions in Bemisia whiteflies (e.g., Rao et al, 2018; Shamimuzzaman et al, 2019; Tay, Elfekih, Polaszek, et al, 2017).…”

“…The use of the maternally-inherited mitochondrial cytochrome oxidase subunit I (mtCOI) partial gene in ‘DNA barcoding’ via the Sanger sequencing method has contributed to molecular diagnostics of species (e.g., Berry et al, 2004; Boykin et al, 2007; Dinsdale, Cook, Riginos, Buckley, & De Barro, 2010; Elfekih, Tay, Gordon, Court, & De Barro, 2018; Tay, Evans, Boykin, & De Barro, 2012), and provided insights into the potential species diversity where cryptic species may co-exist (e.g., Hebert, Cywinska, Ball, & DeWaard, 2003; Rao, Liew, Yow, & Ratnayeke, 2018; Tay, Beckett, & De Barro, 2016). Cryptic species such as the hemipteran whitefly Bemisia tabaci and related ‘non-tabaci’ species are excellent examples where putative species identification can be achieved via molecular characterisation of the partial mtCOI gene (e.g., Lee, Park, Lee, Lee, & Akimoto, 2013; Mugerwa et al, 2018), provided that PCR artefacts, such as NUMTs and/or poor quality sequence trace files and/or gene regions, were first removed (e.g., Elfekih et al, 2019; Kunz, Tay, Elfekih, Gordon, & De Barro, 2019; Tay, Elfekih, Court, et al, 2017; Vyskočilová, Tay, van Brunschot, Seal, & Colvin, 2018).…”

Identification of fermentative bacteria on local microorganisms of golden snail (Pomacea canaliculata Lamarck, 1822)

“…Another material that has potential as a basic material for LMo is the golden snail (P. canaliculata). P. canaliculata is a member of the Ampullaridae tribe which is known as a pest on rice plants (Halwart 2008;Brito and Joshi 2016;Siregar et al 2017;Rao et al 2018). The presence of this pest can damage thousands of hectares of rice seedlings in the early age (Rao et al 2018;Wagiman et al 2019).…”