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Lepocinclis acus (O.F.Muller) B. Marin & Melkonian 2003 in Marin et al. 2003. From the spring-fed acidic freshwater pond in the Two Holes of Water Park white pine forest named Chatfield's Hole. Imaged in Nomarski DIC on Olympus BH2 using SPlan 40X objective plus variable phone camera cropping on Samsung Galxy S9+. Cells measure 125 um in length.

"Emended diagnosis: Cells rigid, fusiform (100– 162 9 7.5–16 µm), apically elongated into a “snout,” terminated with a sharp hyaline tail (on average 12–29 µm). Large, rod-shaped paramylon grains (several to many). Periplast slightly spirally striated following the longitudinal axis" (1).

"Identified based on the fusiform cell shape and size. Of the 19 individuals visible in Ehrenberg’s original drawing many are regularly spindle-shaped, with some showing metaboly. Due to the rigidness of the cell, this seems implausible, as normally the cells only bend. Moreover, the individuals vary significantly in terms of size, what is further confirmed by the handwritten note at the bottom of the image (155, 108–77, 6–58, 2 µm). The cell marked as “b” was chosen as the lectotype as it represents well both the size and shape of a swimming cell (the drawing depicts the effect of the flagellum’s movement). The results presented herein further show that the slightly spiral periplast striation is also a diagnostic trait, one never mentioned by Ehrenberg. The size and shape of the cells as well as the periplast striation distinguish Lepocinclis acus from L. longissima"(1).

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

Lepocinclis fusca from the northernmost pond edge benthos of the spring-fed freshwater coastal pond at Ocean Dunes in the Atlantic Double Dunes reserve situated 250 meters from the edge of the Atlantic Ocean. Measures 42.5 um in length. Imaged in Nomarski DIC using Olympus BH2 under SPlan 40x objective plus variable phone cropping on Samsung Galaxy S9+.

The cell measures 200 um in length and has a pellicle decorated with dense linear arrays of knobby or warty protuberances. The cell has a single twist in the center. There is a rather short pointed tail. The pellicular decorations make it difficult to visualize the paramylon grains. According to Dawson et al. [25], the ornamentations on the cell wall named pellicular warts are iron-enriched and mineralized structures of the extracellular matrix.

"Emended diagnosis: Cells 144–241 mm long, 11–24 mm wide, notably flattened, ribbon-like, ending with a
sharp tail. Periplast striped, in most cases additionally covered with rows of papillae shaped like a pyramid or a truncated pyramid (never as a regular cuboid), with varying numbers of papillae rows and papillae sizes"(1).

The pellicle of Lepocinclis fusca has striations ornamented with pyramid-like structures that form a spiral pattern around the cell. Other characteristic features are the large doughnut-shaped paramylon granules (two per cell) composed of carbohydrate molecules used for energy storage, multiple photosynthetic centers called chloroplasts, and a red eyespot that acts as a light sensor

1. PHYLOGENETIC AND TAXONOMIC POSITION OF LEPOCINCLIS FUSCA COMB. NOV. (=EUGLENA FUSCA) (EUGLENACEAE): MORPHOLOGICAL AND MOLECULAR JUSTIFICATION. Sylwia Kosmala, Anna Karnkowska, Rafał Milanowski, Jan Kwiatowski, Bożena Zakryś. Journal of Phycology Volume 41, Issue 6 p. 1258-1267
2. Phylogeny and taxonomic revision of plastid-containing euglenophytes based on SSU rDNA sequence comparisons and synapomorphic signatures in the SSU rRNA secondary structure. Marin, B., Palm, A., Klingberg, M. & Melkonian, M. (2003) Protist 154: 99-145,

Lepocinclis oxyuris var oxyuris 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+.

The cell measures 225 um in length and is cylindirical to slightly flattened and very slightly twisted with a longitudinal furrow and two large, ring-shaped paramylon grains, one of which is in front of and the other behind the nucleus.

Lepocinclis oxyuris var. oxyuris (Schmarda) B. Marin & Melkonian in Marin et al. 2003: 104. Emended diagnosis: Cells cylindrical (on average 135–210 x 16–22 µm), slightly flattened, hardly metabolic, apically rounded, posterior ending in a sharp hyaline tail (on average 17–30 µm). A furrow runs the entire length of the cell. Flagellum (usually shorter than the length of the cell) allows active swimming; when motile, the cells show a tendency for slight spiral twisting. Two large, ring-shaped paramylon grains, one of which is in front of and the other behind the nucleus; small grains
very few in number (rod-like, oval, ring-like), scattered in the cytoplasm.

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

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).

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