Water sample collected from the river San Pedro, at Las Puentes, Meoqui, Chihuahua, at the indicated location.
The samples was collected on January 7th at 15:41. Images were acquired on January 8th.
A Lake water sample (freshwater) was taken on 11/06/2021 using a 10 micron dip net to enrich for microorganisms.
Probably Peranema, but no clear as some images show a red spot than could be stigma.
all are from a 200ul flush from the roots of this water fern https://www.inaturalist.org/observations/35935190
Rigid, colorless, freshwater euglenoid with one emergent flagellum I believe.
Water sample collected at river Conchos, Julimes, Chihuahua, on December 5th at the indicated location and time.
The images were acquired on December 8th.
A Lake water sample (freshwater) was taken on 11/06/2021 using a 10 micron dip net to enrich for microorganisms.
Mag. 400x
Very small heliozoan (~10µ diamter). Actinophrys does have marine members, but I don't know how small they are. Another possibility is Ciliophrys, a small marine actinophrid heliozoan, https://www.arcella.nl/ciliophrys-infusionum/ and https://www.researchgate.net/publication/296882090_Taxonomy_and_Phylogeny_of_Heliozoa_III_Actinophryids.
From one of the main tidal channels of the salt marsh, a water sample was taken on 11/10/2021 using a 10 micron dip net to enrich for microorganisms.
Continued observation of a sample collected 20210314 from a river tributary, scoop of sediment near the bank.
Three different shells.
Genus Hyalosphenia?
Flagellum was slightly visible at times but did not show up in this image.