Cryptic diversity in a cosmopolitan diatom known as Asterionellopsis glacialis (Fragilariaceae): Implications for ecology, biogeography, and taxonomy

Abstract

The morphological diversification of the species examined in this study lags behind their genetic divergence. The currently accepted 2% cutoff level of operational taxonomic unit (OTU) clustering in 18S rDNA environmental sequencing is too high to recognize genetic diversity in Asterionellopsis and very likely in many other species. Our results support the notion that a considerable number of species and diversity remain to be discovered among diatoms and that species number may be more in line with higher estimates. Molecular signatures of the species discovered here will aid in their globally consistent identification and ultimate understanding of their ecology.

The impact of OTU sequence similarity threshold on diatom‐based bioassessment: A case study of the rivers of Mayotte (France, Indian Ocean)

“…DNA barcoding has enabled the rapid development of novel molecular techniques that have greatly improved the quality of species identification (Hebert, Cywinska, Ball, & deWaard, 2003). These DNA-based methods are efficient and reduce misidentifications due to phenotypic plasticity (Leliaert et al, 2014) or cryptic diversity (Kaczmarska, Mather, Luddington, Muise, & Ehrman, 2014). These DNA-based methods are efficient and reduce misidentifications due to phenotypic plasticity (Leliaert et al, 2014) or cryptic diversity (Kaczmarska, Mather, Luddington, Muise, & Ehrman, 2014).…”

Temporal variation of Skeletonema community composition from a long-term time series in Narragansett Bay identified using high-throughput DNA sequencing

“…Kooistra et al 2008), Chaetoceros (e.g. Beszteri et al 2005, Amato et al 2007, Kooistra et al 2010, Lundholm et al 2012, Asterionellopsis (Kaczmarska et al 2014) and Leptocylindrus (Nanjappa et al 2013).…”

Ecology and Evolution of Marine Diatoms and Parmales

“…This is refl ected in studies investigating cryptic species, highlighted by the classic work of Mann and colleagues on the benthic freshwater genus Sellaphora (Mann et al 2008 ;Evans et al 2008 ;Poulíčková et al 2008 ). Cryptic species are also common in marine habitats such as in the benthic estuarine species Navicula phyllepta (Vanelslander et al 2009 ) and the cosmopolitan planktonic diatoms Asterionellopsis glacialis (Kaczmarska et al 2014 ) and Skeletonema costatum (Sarno et al 2005 ;Kooistra et al 2008 ). In living diatoms, it may be possible to resolve some of the underlying problems of cryptic species by including more characters for taxonomy (e.g., genetics and sexual reproduction), but this will not be possible for fossil forms of extinct species found in sediments, where only the remains of the cell wall are found.…”