Life Cycle of Nitzschia palea (Kützing) W. Smith (Bacillariophyta)

Phylotranscriptomics reveals the reticulate evolutionary history of a widespread diatom species complex

“…Moreover, broader morphometric ranges for the characters measured here have been recorded from other clones of N. palea (Bagmet et al. 2020 ), highlighting that the full range of morphological variation present in this species complex was not represented by the limited number of strains in this study, and many more populations need to be sampled for discussion of N. palea morphology. Nonetheless, our species tree estimations recovered ‘ N. palea mating group 1’ as sister to the common ancestor of Clade A and Clade B, whereas the remaining three lanceolate strains (Clade A) were recovered as sister to the linear‐lanceolate Clade B strains, with maximum support values for both relationships (Fig.…”

“…However, all three Clade A strains had many deformed valves and missing data, so it is not easy to compare these two groups based on morphometric data alone. Moreover, broader morphometric ranges for the characters measured here have been recorded from other clones of N. palea (Bagmet et al 2020), highlighting that the full range of morphological variation present in this species complex was not represented by the limited number of strains in this study, and many more populations need to be sampled for discussion of N. palea morphology. Nonetheless, our species tree estimations recovered 'N.…”

“…( 2009 ) and Bagmet et al. ( 2020 ), which were shown to be incapable of sexual reproduction without a compatible partner (i.e., they were heterothallic). Its stria density varied the least among all strains analyzed, providing corroborative evidence for the presence of a single strain with two different length ranges, possibly representing different stages of its growth cycle (Table S1 ).…”

“…For example, our data set revealed a large degree of gene-tree discordance, suggesting a recent divergence of this species complex that may not be accurately estimated with standard molecular clock approaches and highlighting that studies based on one or a few markers are not guaranteed to recover the organismal phylogeny. The recent study of N. palea by Bagmet et al (2020) illustrates this differently: eight of the nine original clones they studied were shown to be reproductively compatible, producing a viable F1 (the ninth was incapable of sexual reproduction because of its small size), but these eight fell into two widely separated groups based on partial cox1 sequences, differing from each other by a remarkable 73 substitutions (in 679 aligned bp). Genomescale analyses of unlinked nuclear genes also allowed us to identify a putative hybrid resulting from recent gene flow between lineages with different morphologies.…”

Phylotranscriptomics Reveals the Reticulate Evolutionary History of a Widespread Diatom Species Complex

“…However, all three Clade A strains had many deformed valves and missing data, so it is not easy to compare these two groups based on morphometric data alone. Moreover, broader morphometric ranges for the characters measured here have been recorded from natural N. palea populations (Bagmet et al 2020), highlighting that the full range of morphological variation present in this species complex was not represented by the limited number of strains in this study, and many more populations need to be sampled for discussion of N. palea morphology. Nonetheless, our species tree estimations recovered 'N.…”