Lepocinclis pseudospiroides (Svirenko) Zakryś & Chaber 2022 belonging to the species complex Lepocinclis tripteris (Dujardin) B.Marin & M.Melkonian 2003 from the northernmost edge benthos, situated 250 meters from the edge of the Atlantic Ocean, of the spring-fed freshwater coastal pond at Ocean Dunes Apartments in the Atlantic Double Dunes Reserve. Imaged in Nomarski DIC on Olympus BH2 using SPlan 40x objective plus phone camera cropping on Samsung Galaxy S9+.
"Lepocinclis was described in the 19th century (Perty 1849), but its diagnostic description was emended at the beginning of the 21st century due to five species being transferred from Euglena into Lepocinclis based on molecular data (L. acus, L. butschlii, L. oxyuris, L. ovum, and L. tripteris; Marin et al.
2003). Lepocinclis is currently classified in the family Phacaceae, together with the representatives of Phacus, Discoplastis (Kim et al. 2010) and Flexiglena (Łukomska-Kowalczyk et al. 2021). All family representatives possess numerous, discoidal, parietal chloroplasts without pyrenoids" (1).
Measuring 225 um in length, this is more consistent with Lepocinclis pseudospiroides (Svirenko) Zakryś & Chaber comb. nov. (Fig. 3 l and m) (1).
"Emended diagnosis Lepocinclis pseudospiroides (Svirenko) Zakryś & Chaber comb. nov.: The rigid, corkscrew-like cells resemble in shape those of Lepocinclis tripteris, however are twice as large (131–230 × 12–25 µm, hyaline tail 16–36 µm long). The spiral twists of the body are loose, but more numerous (usually there are three) as the cells are longer. Periplast longitudinally striated. Two large, rod-shaped paramylon grains (one of which is in front of and the other behind the nucleus)" (1).
"Comments: Polish populations were identified based on the cell size and the level of “body twisting”. Out of three drawings by Svirenko (see Fig. S10), fig. 1, was chosen as the lectotype, as the corkscrew-shaped cell visibly has three wings (is triangular in cross section), is slightly twisted and possesses two rod-like paramylon grains. Due to the similarity between Lepocinclis pseudospiroides and other taxa from the L. tripteris-like group (e.g., L. tripteris or L. torta), the designation of an epitype seems justified (for more details see Discussion section). Euglena trisulcata has been included as a L. pseudospiroides synonym due to the similar cell size and lack of other diagnostic traits that would distinguish the two species" (1).
"Lepocinclis tripteris-like group of taxa.
Lepocinclis tripteris (60–80 µm long) was first described as Phacus tripteris Dujardin (1841), and later moved by Klebs (1883) to Euglena (as E. tripteris). A century later, E. fronsundulata (Johnson 1944) was described from the USA, which differed from E. tripteris only by a smaller size (42–53 × 4–7 µm) and a shorter flagellum. Similar form, though more tightly twisted, was described by Stokes from the USA (1885, as E. torta, 63.5 µm long) and also by Svirenko from Ukraine (1915a, as E. tripteris var. crassa, cells: 63–83 × 15–21 µm). The literature mentions two additional taxa that are identical to E. tripteris in terms of cell shape (loosely twisted), though twice as long. The first was described from Ukraine as E. tripteris var. major (Svirenko 1915a), and later elevated to the rank of species (E. pseudospiroides Svirenko 1915b, cells: 131–192 × 18–22 µm). The second was noted from the USA as E. trisulcata Johnson (1944, cells: 205–220 × 11–15 µm).
"The authors of critical monographs interpret differently the validity of distinguishing taxa based on cell size and the degree of twisting: Pringsheim (1956) is very skeptical; Gojdics (1953) includes Euglena torta as a synonym of E. tripteris and distinguishes E. pseudospiroides, E. trisulcata and E. fronsundulata; Popova (1966) deems only three varieties of E. tripteris as valid (typica, crassa, and major), and treats E. torta (similarly to Gojdics) as a synonym var. typica, while neither E. trisulcata nor E. fronsundulata are mentioned by her. In Figure 2, the three morphologically different forms (see Figs. 3, h-m and S2), that is slightly twisted, short (on average 100 µm), slightly twisted, long (on average 200 µm) and tightly twisted, short cells (on average 80 µm) occur as separate groups that have been named respectively: tripteris, pseudospiroides and torta (Figs. 2, S4)" (1).
Toward the robust resolution of taxonomic ambiguity within Lepocinclis (Euglenida) based on DNA sequencing and morphology
Katarzyna Chaber, Maja Łukomska-Kowalczyk, Alicja Fells, Rafał Milanowski, Bożena Zakryś. Phycol. 58, 105–120 (2022).
https://onlinelibrary.wiley.com/doi/full/10.1111/jpy.13220
