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Jenningsia macrostoma (Ekebom et al., 1996) Lee, Blackmore and Patterson 1999 from the northernmost saprobic edge benthos of the spring-fed freshwater coastal pond at Ocean Dunes Apartments in the Atlantic Double Dunes Preserve. The sampling site is just 200 meters from the edge of the Atlantic Ocean.

Imaged in Nomarski DIC on Olympus BH2S using SPlanapo 20 0.70, Splanapo 40 0.95, and SPlan 100 1.25 oil objectives plus variable phone cropping on Samsung Galaxy S9+.

The cells are highly metabolic and measure up to 130 um when fully extended. There are fine pellicular striations in an s-helix configuration. There is a single thick emergent flagellum. Two large ingestion apparatus rods are apparent along with a curved refractile cytoskeletal arc arising from the right rod and curving towards the anterior of the cell. There is a large ellipsoid macronucleus with several large nucleoli in the posterior part of the cell.

"Jenningsia macrostoma (Ekebom et al., 1996) Lee, Blackmore and Patterson, n. comb. This species has been reported with lengths from about 64 to 114 µm. The body is anteriorly narrowed and posteriorly rounded. It is very metabolic and has fine pellicular striations following a S-helix. The flagellar pocket is situated on the left ventral face of the cell. Two flagella are seen in the flagellar pocket, but only one flagellum emerges. The flagellum is slightly shorter than the cell and beats freely. The ingestion apparatus with two well marked rods is strongly developed. A refractile cytoskeletal arc arises from the right rod and curves towards the anterior of the cell. Optical sections through the anterior part of the cell show this as a short curving structure extending from near the front pole of the cell to near the anterior end of the ingestion rods. The nucleus is situated in the posterior part of the cell. Refractile granules are randomly distributed inside the cell. Rod-shaped muciferous bodies lie alongside pellicluar striations. Cells glide with a squirming movement. Less common than J. fusiforme" (1).

"This species has been described as Peranema macrostoma from marine sites at tropical and subtropical Australia, Brazil (Larsen and Patterson, 1990; Ekebom et al., 1996; Lee and Patterson, 1999). Like Peranema fusiforme, it has been known that P. macrostoma has a short, curved recurrent flagellum which is tightly pressed to the cell surface (Ekebom et al., 1996). Figure 4h was taken from Ekebom et al. (1996; Fig. 4e). In this figure, the recurrent flagellum was indicated by an arrow, but the arrow indicates the curving element of the intracellular cytoskeleton. Only one flagellum emerges from the anterior opening canal as there is no recurrent flagellum emerging from the slit-like opening of the flagellar pocket (Fig. 4k)" (1).

"Jenningsia and Peranemopsis were created by Schaeffer (1918) and Lackey (1940) respectively to contain peranemid flagellates having one emergent flagellum and flexible body with pellicular striations. They are distinguished from the genus Peranema by having one flagellum, other species having a recurrent flagellum lying in a groove on the ventral face of the body (Fig. 4g). Peranema fusiforme and P. macrostoma have been described with a short, curved recurrent flagellum which is tightly pressed to the cell surface (Larsen, 1987; Larsen and Patterson, 1990; Ekebom et al., 1996). Figure 4a of Peranema fusiforme was taken from Larsen and Patterson (Larsen and Patterson 1990; Fig. 24e) and figure 4h is of Peranema macrostoma and from Ekebom et al. (Ekebom et al., 1996; Fig. 4e), respectively. In these figures, the structure that was interpreted as the recurrent flagellum was indicated by arrows. Our present observations of both species indicate that the structure is a previously undescribed element of the cytoskeleton associated with the ingestion apparatus. As seen in figures 4d and 4k, only one flagellum emerges from the anterior opening canal (arrows). We are therefore of the view that both of these species lack an emerging recurrent flagellum. As the genus Jenningsia was described and distinguished from Peranema on the basis of the absence of the second flagellum, we believe these two species are most appropriately transferred to that genus. Peranemopsis was described by Lackey (Lackey, 1940) also as a peranemid with a single emergent flagellum. It was described without reference to Jenningsia" (1).

1. Australian records of two lesser known genera of heterotrophic euglenids – Chasmostoma Massart, 1920 and Jenningsia Schaeffer, 1918 W.J. Lee, R. Blackmore and D.J. Patterson. Protistology 1, 10-16 (1999).

Water sample taken from the edge of a freshwater playa on 2023-12-07 using a turkey baster.

The images show the flattened ovoid shape of the test with a lens like cross section. No rod like spines are visible. There do appear to be xenosomes. The third image seems to show a CV and nucleus. It seems to be between 30 and 40 microns long.

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