PHYLOGENY OF THE EUGLENOID LORICATE GENERA TRACHELOMONAS AND STROMBOMONAS (EUGLENOPHYTA) INFERRED FROM NUCLEAR SSU AND LSU rDNA¹

Abstract

Previous studies using the nuclear SSU rDNA and partial LSU rDNA have demonstrated that the euglenoid loricate taxa form a monophyletic clade within the photosynthetic euglenoid lineage. It was unclear, however, whether the loricate genera Trachelomonas and Strombomonas were monophyletic. In order to determine the relationships among the loricate taxa, SSU and LSU nuclear rDNA sequences were obtained for eight Strombomonas and 25 Trachelomonas strains and combined in a multigene phylogenetic analysis. Conserved regions of the aligned data set were used to generate maximum-likelihood (ML) and Bayesian phylogenies. Both methods recovered a strongly supported monophyletic loricate clade with Strombomonas and Trachelomonas species separated into two sister clades. Taxa in the genus Strombomonas sorted into three subclades. Within the genus Trachelomonas, five strongly supported subclades were recovered in all analyses. Key morphological features could be attributed to each of the subclades, with the major separation being that all of the spine-bearing taxa were located in two sister subclades, while the more rounded, spineless taxa formed the remaining three subclades. The separation of genera and subclades was supported by 42 distinct molecular signatures (33 in Trachelomonas and nine in Strombomonas). The morphological and molecular data supported the retention of Trachelomonas and Strombomonas as separate loricate genera.

Photosynthetic Euglenoids

“…The lorica is generated from an aggregation of mucilaginous strands secreted from the cell. Much of the traditional taxonomy is based upon the morphology of the lorica, which varies, but this is slowly changing through the use of molecular phylogenetics (e.g., see Ciugulea et al, 2008). 3).…”

“…Literature useful for species identification belonging to particular genera Euglena/Euglenaria Classical literature: Chu (1946), Gojdics (1953), Pringsheim (1956), Popova (1966), Zakryś (1986), and Zakryś and Walne (1994) The Classical literature: Conrad (1934Conrad ( , 1935 The recent literature concerning taxonomic verifications: Marin et al (2003) and Kosmala et al (2005) (L. fusca and L. spirogyroides), Bennett and Triemer (2012) (L. helicoideus. L. horridus) Trachelomonas/Strombomonas Classical literature: Deflandre (1926Deflandre ( , 1927, Conrad and van Mell (1952), and Popova (1966) The recent literature: Conforti and Joo (1994), Brosnan et al (2005), Ciugulea et al (2008), and Conforti (2009Conforti ( , 2010 LITERATURE CITED…”

DNA barcoding in autotrophic euglenids: evaluation of COI and 18s rDNA

“…Sequences from Stromobomonas and Trachelomonas were assigned to the clades described by (Ciugulea et al. ), since taxonomic verification was not carried out for these two genera. 18S rDNA sequences shorter than the region between helix 8 and helix 49 were excluded from analyses of the 18S rDNA fragments.…”

Strombomonas Deflandre (Euglenophyceae) em ambientes aquáticos na Área de Proteção Ambiental do Ibirapuitã, Estado do Rio Grande do Sul, Brasil

“…Marin et al (2003) realizaram estudos com biologia molecular e propuseram que os táxons destes dois gêneros loricados deveriam ser incorporados ao gênero Trachelomonas. No entanto, este e outros estudos recentes com multigenes e um maior número de representantes indicou que os gêneros Strombomonas e Trachelomonas devem continuar separados com base em filogenia molecular, na ontogenia do desenvolvimento da lorica e padrão de redução das estrias da película (Brosnan et al 2005, Triemer et al 2006, Ciugulea et al 2008, Kim & Shin 2008, Linton et al 2010e Kim et al 2015.…”