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Mag. 100x (4), 400x (1-3)

• A pond-side water sample (retentate) was taken using a 10µ dip net to enrich for microorganisms. Air temp 58F.

Heliozoan filled with zoochlorella. Note that shorter spine-scales are bifurcated, which is characteristic of A. turfacea. For information and reference images, see https://arcella.nl/acanthocystis-turfacea/.

Thanks to Ryan Gawryluk for identifying this heliozoan as Ciliophrys species from biofilm that developed in a week old sample from the intertidal benthos of marine estuary Acabonac Harbor at Louse Point launching ramp. The cell body measures 15 um in diameter and has axiopods extending in three dimensions with granular kinetocysts. They taper slightly from base to tip. The long flagellum is held in a double figure 8 pattern. There are peripheral clumps of heterochromatin in the nucleus. These features are all indicative of Ciliophrys azurina Mirkujov and Patterson 2001 (1). In the first video we can see a bacterium being captured in a bag-like pseudopodium as depicted by Siemensma (2).

"Ciliophrys is a naked and heterotrophic pedinellid with either no stalk or a short stubby stalk (unpublished ultrastructural information). It is distinguished from other pedinellid taxa without plastids because the arms radiate from the whole cell surface, and, while in the heliozoan state, has weakly active flagellum held in a figure of 8 configuration. The cell may convert into an arm-less form at which time the flagellum becomes more active and the pseudopodia are withdrawn. These arm-less cells usually swim with the flagellum directed to the front. The fine, non-tapering axopods are supported by single triads of microtubules. As with actinophryids and other pedinellids, the interior ends of these axonemes are associated with nuclei. The composition of the genus was discussed by Larsen and Patterson (1990). We currently admit two species, and here add a third" (1).

"Ciliophrys azurina Patterson, sp. n. Diagnosis. Ciliophrys with tapering arms; nucleus with a central nucleolus and additional peripheral heterochromatin. Description. Cell 15 µm in diameter, with radiating arms with extrusomes. The single flagellum is held in front of swimming cells, and in non-swimming (feeding) cells the flagellum is held tightly curled, typically in a double “figure of 8”. The nucleus is large, prominent and has a nucleolus and clumps of material located around the inner face of the nuclear envelope. Observed consuming diatoms" (1).

"Remarks. Ciliophrys azurina can be distinguished from the other well described species in the genus, C. infusionum, by being considerably larger (15 µm vs 5 µm, although we note that C. infusionum has been reported as up to 20 µm long). More importantly, C. azurina can also be distinguished because the flagellum is longer and held in a double “figure of 8”, because the arms taper from base to tip, and because of the existence of peripheral clumps of heterochromatin in the nuclei. These two characters are held in common with Actinophrys - and there is especial similarity with Actinophrys pontica. We interpret the tapering arms and peripheral heterochromatin as being apomorphic characters for a previously unrecognised clade which includes C. azurina and the two genera of actinophryids and which we here refer to as the heliomonads" (1).

Imaged in Nomarski DIC using Olympus BH2S under SPlan 100x objective and oiled condenser plus variable phone camera cropping on Samsung Galaxy S9 + . One video includes some choanoflagellates just because they are so cute.

1. Taxonomy and Phylogeny of Heliozoa. III. Actinophryids Kirill A. MIKRJUKOV and David J. PATTERSON. Acta Protozool. (2001) 40: 3-25.
2. https://arcella.nl/ciliophrys-infusionum/

Thanks to Ryan Gawryluk for identifying this heliozoan as Ciliophrys species from biofilm that developed in a week old sample from the intertidal benthos of marine estuary Acabonac Harbor at Louse Point launching ramp. The cell body measures 15 um in diameter and has axiopods extending in three dimensions with granular kinetocysts. They taper slightly from base to tip. The long flagellum is held in a double figure 8 pattern. There are peripheral clumps of heterochromatin in the nucleus. These features are all indicative of Ciliophrys azurina Mirkujov and Patterson 2001 (1). In the first video we can see a bacterium being captured in a bag-like pseudopodium as depicted by Siemensma (2).

"Ciliophrys is a naked and heterotrophic pedinellid with either no stalk or a short stubby stalk (unpublished ultrastructural information). It is distinguished from other pedinellid taxa without plastids because the arms radiate from the whole cell surface, and, while in the heliozoan state, has weakly active flagellum held in a figure of 8 configuration. The cell may convert into an arm-less form at which time the flagellum becomes more active and the pseudopodia are withdrawn. These arm-less cells usually swim with the flagellum directed to the front. The fine, non-tapering axopods are supported by single triads of microtubules. As with actinophryids and other pedinellids, the interior ends of these axonemes are associated with nuclei. The composition of the genus was discussed by Larsen and Patterson (1990). We currently admit two species, and here add a third" (1).

"Ciliophrys azurina Patterson, sp. n. Diagnosis. Ciliophrys with tapering arms; nucleus with a central nucleolus and additional peripheral heterochromatin. Description. Cell 15 µm in diameter, with radiating arms with extrusomes. The single flagellum is held in front of swimming cells, and in non-swimming (feeding) cells the flagellum is held tightly curled, typically in a double “figure of 8”. The nucleus is large, prominent and has a nucleolus and clumps of material located around the inner face of the nuclear envelope. Observed consuming diatoms" (1).

"Remarks. Ciliophrys azurina can be distinguished from the other well described species in the genus, C. infusionum, by being considerably larger (15 µm vs 5 µm, although we note that C. infusionum has been reported as up to 20 µm long). More importantly, C. azurina can also be distinguished because the flagellum is longer and held in a double “figure of 8”, because the arms taper from base to tip, and because of the existence of peripheral clumps of heterochromatin in the nuclei. These two characters are held in common with Actinophrys - and there is especial similarity with Actinophrys pontica. We interpret the tapering arms and peripheral heterochromatin as being apomorphic characters for a previously unrecognised clade which includes C. azurina and the two genera of actinophryids and which we here refer to as the heliomonads" (1).

Imaged in Nomarski DIC using Olympus BH2S under SPlan 100x objective and oiled condenser plus variable phone camera cropping on Samsung Galaxy S9 + . One video includes some choanoflagellates just because they are so cute.

1. Taxonomy and Phylogeny of Heliozoa. III. Actinophryids Kirill A. MIKRJUKOV and David J. PATTERSON. Acta Protozool. (2001) 40: 3-25.
2. https://arcella.nl/ciliophrys-infusionum/

Mag. 400x

• A pond-side water sample was taken on 07/31/2023 using a 10µ dip net to enrich for microbes. Air temp. 75°F.

Small flagellate with a probing "nose". My scope could not resolve the critter cleanly, but it was fun to chase, after it swam into my field of view. (The 2nd image shows the small, inconspicuous, shadowy figure as it appeared in the 400x field.) I could only see it for a short interval before I lost the ability to track it. For fabulous images and video of R. nasuta, see the observations posted by iNatters @crseaquist and @zookanthos: https://www.inaturalist.org/observations?verifiable=true&taxon_id=881489&place_id=97394&preferred_place_id=1&locale=en-US.