Toward the robust resolution of taxonomic ambiguity within Lepocinclis (Euglenida) based on DNA sequencing and morphology

Abstract

DNA sequences were analyzed for three groups of species from the Lepocinclis genus (L. acus‐like, L. oxyuris‐like, and L. tripteris‐like) along with cellular morphology. Phylogenetic analyses were based on nuclear SSU rDNA, LSU rDNA, and plastid‐encoded LSU rDNA. DNA sequences were obtained from species available in culture collections (L. acus SAG 1224‐1a and UTEX 1316) and those isolated directly from the environment in Poland (48 isolates), resulting in 79 new sequences. The obtained phylogenetic tree of Lepocinclis included 27 taxa, five of which are presented for the first time (L. convoluta, L. gracillimoides, L. longissima, L. pseudospiroides, and L. torta) and nine taxonomically verified and described. Based on morphology, literature data, and phylogenetic analyses, the following species were distinguished: in the L. acus‐like group, L. longissima and L. acus; in the L. tripteris‐like group, L. pseudospiroides, L. torta, and L. tripteris; in the L. oxyuris‐like group, L. gracillimoides, L. oxyuris var. oxyuris, and L. oxyuris var. helicoidea. For all verified species, diagnostic descriptions were emended, nomenclatural adjustments were made, and epitypes were designated.

Molecular and morphological delimitation of species in Strombomonas (Euglenaceae) including a protocol for DNA isolation utilising a chelating resin

“…1), 10 species are recognized here. Given the strong congruence between morphological characters and the clades recovered in our phylogenetic analyses, the range of intra‐ and interspecific genetic distances in Strombomonas is similar to other related genera: Discoplastis (Łukomska‐Kowalczyk & al., 2021), Lepocinclis (Łukomska‐Kowalczyk & al., 2020; Chaber & al., 2022) and Phacus (Karnkowska‐Ishikawa & al., 2010; Kim & Shin, 2014; Łukomska‐Kowalczyk & al., 2015).…”

“…Although much is known about the morphology and development of lorica in Strombomonas , little has been published regarding the monad morphology of particular species, especially in terms of chloroplast number and morphology, as well as pyrenoid and paramylon cap presence (see, e.g., Pringsheim, 1953; Popova, 1966; Brosnan & al., 2003; Kim & al., 2015). The above features are important diagnostic characters in non‐loricate euglenids (see, e.g., Łukomska‐Kowalczyk & al., 2020, 2021; Chaber & al., 2022), yet they have gone practically unused in Strombomonas .…”

“…According to AlgaeBase, there are 275 Strombomonas names (specific and infraspecific), only 96 of which are taxonomically accepted species names (Guiry, 2018). While this may suggest that there is considerable species richness within Strombomonas , the actual number is likely significantly lower if studies in other Euglenaceae are a guide (e.g., Łukomska‐Kowalczyk & al., 2020; Chaber & al., 2022). Moreover, understanding of the ecology, geographic distribution, and functional role of Strombomonas is largely lacking.…”