Cryptomonas paramaecium (Ehrenberg) Hoef-Emden & Melkonian 2003 = Chilomonas paramaecium Ehrenberg 1831

This organism is a hoax. It has supposedly already been reclassified as another species of Cryptomonas campylomorph form (no cryptomorph has been found), but in any case, AlgaeBase still considers it the type (lectotype) of the genus Chilomonas, since it was previously considered part of that genus, different from Cryptomonas. There is another name used, which is "Chilomonas paramecium", instead of "paramaecium". It appears as such in Clay (2015).

This species belongs to the family Cryptomonadaceae, order Cryptomonadales, class Cryptophyceae (commonly called "cryptomonad algae"). You know where this is going: cryptomonad algae are then included in the subphylum Rollomonadia, phylum Cryptista, subkingdom Hacrobia, kingdom Chromista. 

The kingdom Chromista is related to the clade Archaeplastida, which includes algae that are relatives and ancestors of plants. You might also encounter another classification, where the phylum Cryptista is included in the clade Pancryptista, which is related to Archaplastida, and both form the large CAM clade. But that's not really important; the point is that Cryptomonas paramaecium is another distant relative of plant ancestors.

Reminder that it is free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026). The sources I used and read for the creation of the image, as well as the text where I explain, are these:

• "Chapter 18 - Cryptomonads". Brec L. Clay, 2015. Freshwater Algae of North America (Second Edition). Academic Press.
• "Cryptomonas paramaecium (Ehrenberg, 1832) Hoef-Emden & Melkonian, 2003". Martin Kreutz. Real Micro Life 2021.
• "Revision of the Genus Cryptomonas (Cryptophyceae): a Combination of Molecular Phylogeny and Morphology Provides Insights into a Long-Hidden Dimorphism". Kerstin Hoef-Emden and Michael Melkonian. Protist, Volume 154, Issues 3-4, 371-409 pp. 2003.

As I mentioned, C. paramaecium has a campylomorph form. This means a simple furrow without stomata and an almost sigmoid cell shape, although in this species, the shape is usually more ovate-elongated and slightly wider anteriorly. The vestibulum has a vestibular ligule (this ligule is absent in the cryptomorph form in another species). The furrow is quite small compared to others.

Most notably, it lacks chloroplasts and pyrenoids, instead possessing leucoplasts with starch grains and nucleomorphs (one in each chloroplast). Therefore, it doesn't have a red or green pigment to give it color; it is transparent (though under a microscope it appears grayish or glassy). In this image, I've used various grayish to bluish tones and other minor colors, but it's important to remember that the objective is more didactic than realistic.

Dimensions: 14–28 µm long × 10–13 µm wide × 8–10 µm thick. However, Clay (2015) attributes larger sizes to it, 20–40 µm long and 10–20 µm in diameter.

Other observed features include the contractile vacuole at the anterior extreme of the cell, two Maupas bodies located approximately in the cell's central region, and the gullet surrounded by ejectisomes (few are illustrated in Clay (2015), but more are seen in the micrographs by Kreutz (2021).

According to Kreutz (2021), flagella are slightly shorter than the cell and the same length, but in the illustrations from both that source and Clay (2015), they are depicted as shorter relative to the cell, and I have represented them accordingly, choosing to make them approximately half the size of the cell. Although both are equal in length (again, in the illustrations in Kreutz (2021) and Clay (2015), they are not depicted at the same lengths), I have chosen to represent the longer flagellum slightly longer than the shorter (ventral) one.

I have drawn the endoplasmic reticulum, Golgi apparatus, and the single reticulated mitochondrion. The shapes of these structures are speculative. In the case of the mitochondrion, it's a predicted reticulated shape based on what Santore and Greenwood (1977) explains, where it's mentioned that Cryptomonas has a single mitochondrion with numerous branches distributed throughout the cell, concentrated in areas like the gullet. It's assumed that these mitochondrial branches should have different thicknesses in various sections, but in my drawing, the width of these branches is almost uniform.

According to Kugrens et al. (1987): unlike other species, the flagella do not follow the basic type 1 flagellar arrangement (long dorsal flagellum with two rows of mastigonemes, each with a terminal filament; short ventral flagellum with one row of mastigonemes, each with two unequal terminal filaments). Instead, there is a type 4 flagellar arrangement. In this arrangement, there is only one row of mastigonemes for both flagella. The nature of the terminal filaments is the same as in type 1 flagella. Therefore: long (dorsal) flagellum with one row of mastigonemes, each with a terminal filament; short (ventral) flagellum with one row of mastigonemes, each with two unequal terminal filaments. Additionally, at the terminal tip of the long flagellum, there are four "terminal hairs".

Both the mastigonemes and the additional filaments and hairs can only be seen with an electron microscope. Don't expect to see them with a light microscope. Even the flagella are sometimes difficult to see with a light microscope. I almost forgot: both flagella are located on the right side of the vestibule. That's from a dorsal view. In a ventral view, they appear to be on the left, but that's just an illusion!

I have nothing more to say in this post about this organism. In theory, this was supposed to be the entry about Giardia duodenalis, but I had some anatomical questions about its microtubules and I'm investigating it to see if I need to make any further corrections. 

Anyway, that's how, with this organism, I've reached illustration number 20 out of the 100 I have to complete. But hey. It's more fun to say I'm 80 short than 96.

Hatena arenicola N.Okamoto & Inouye 2006

I'm happy to report that despite everything, I was finally able to find the time to finish this illustration and break out of my 20-illustration slump. I actually have another one ready from last year, but I want to save that one for later; in fact, I hope to explain it in a future post. And I apologize for any discomfort or strangeness you may have felt.

In this post, I present the illustrations I've created of Hatena arenicola N.Okamoto & Inouye 2006. The illustrations are free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

It belongs to the family Katablepharidaceae, order Katablepharidales, class Katablepharidophyceae, which is part of the subphylum Rollomonadia. This means that Hatena arenicola is related to cryptomonad algae (class Cryptophyceae) and goniomonads (class Goniomonadophyceae), which are also within Rollomonadia. Aside from that, it's the same story I've explained in other posts: Rollomonadia belongs to the phylum Cryptista, clade Pancryptista, and CAM clade. The latter includes Archaeplastida as the sister group to Pancryptista, and encompasses the plants and algae related to its ancestors. Therefore, Hatena arenicola is a distant relative of plants. It's also worth mentioning that another way to classify it is to include the phylum Cryptista as part of the subkingdom Hacrobia, kingdom Chromista, and superkingdom Corticata, where the other kingdom is Plantae. But anyway, the conclusions regarding relationships are almost the same.

I consulted a single source for the morphological and descriptive information of Hatena arenicola, as well as the primary source for the illustrations: "Hatena arenicola gen. et sp. nov., a Katablepharid Undergoing Probable Plastid Acquisition" by Noriko Okamoto and Isao Inouye (2006).

What's curious about this organism is that it seems to have been left "halfway" in the process of acquiring chloroplasts. To give you some context, it's believed that modern plants evolved from eukaryotes that acquired photosynthetic bacteria (primary endosymbiosis, including the ancestors of Viridiplantae, Glaucophyta, and Rhodophyta) or algae (that is, eukaryotes that already had a photosynthetic bacterium integrated as a chloroplast). This latter case is known as secondary endosymbiosis, and includes Euglenophyta and Chlorarachniophyta (which acquired green algae), as well as Heterokontophyta, Haptophyta, Cryptophyta, Dinophyta, and Apicomplexa (which acquired red algae).

There is some evidence of organisms that have undergone secondary endosymbiosis, but very little about how this process occurred. And that's what makes Hatena arenicola stand out, as it appears to be an organism that hasn't yet fully integrated an alga as an organelle. Instead, it's "halfway" integrated; it has a life cycle where it can live freely, and it captures a free-living alga (of the genus Nephroselmis), which it doesn't digest (as it would with other algae), but rather integrates as another part of its body, in a state of endosymbiosis.

That's why it's best to present the following image as the front page:

The illustration essentially depicts how an individual of Hatena arenicola, lacking a symbiotic alga, possesses a feeding apparatus (predatory phase). It uses this apparatus to ingest the symbiotic alga, which then integrates with it, giving rise to the symbiotic state of Hatena arenicola. Due to the process of acquiring the symbiont, the feeding apparatus disappears. When it needs to divide, the nucleus (originally located posteriorly) shifts to the anterior region. The organism divides, with one daughter cell retaining the symbiont and the other not. This daughter cell without a symbiont will develop a feeding apparatus and continue its predatory phase until it acquires another symbiotic alga, Nephroselmis. The daughter cell that inherited the symbiont can continue its life in the "plant phase," living off the photosynthesis provided by the symbiont, and can divide again, generating one daughter cell with a symbiont and another without. As an additional note, I consulted "Phylogeny and ultrastructure of Nephroselmis and Pseudoscourfieldia (Chlorophyta), including the description of Nephroselmis anterostigmatica sp. nov. and a proposal for the Nephroselmidales ord. nov." by Nakayama et al. (2007) for information on the ventral and dorsal locations of the Nephroselmis symbiont.

That said, it is clear that Hatena arenicola has at least two main states: with a symbiont and without a symbiont. Let's begin with the state with the symbiont stage. Hatena arenicola does not possess a feeding apparatus in this stage. Aside from that, it does have everything else: a furrow from which the flagella emerge (the exact area where they emerge is known as the "flagellar insertion zone"). The flagella are derived from basal bodies, which I haven't shown here. There are two types of ejectisomes: type I (large, arranged in two rows near the flagellar insertion zone), and type II (smaller, distributed in numerous rows throughout the cell, except in the area surrounding the symbiont's eyespot).

In addition to the ejectisomes, it also has a nucleus located in the middle posterior region of the cell (when the cell is not ready to divide), with electron-dense chromatin that is always condensed (i.e., in a heterochromatic state). I've represented this heterochromatin as darker clumps in the nucleus; I think it's more visible in the version without the symbiont, which I'll discuss later. In addition to the nucleus, there is also a single "Golgi body" between the nucleus and the flagellar apparatus (basal bodies + flagella). In Figure 6D, you can see some "lines" within the Golgi body, and that's how I've chosen to represent it as well. Next to the Golgi body, 

I've depicted a lysosome, which is evidence of the predatory lifestyle of Hatena arenicola. It's assumed that this organism lives by preying on other algae until it finds a Nephroselmis symbiont. With other algae, it simply digests them completely, and their scales may remain within the lysosomes. I don't know how many lysosomes there are, but I've only depicted one, containing Pyramimonas scales. In the context of these illustrations, and especially for this one of the symbiotic state, it's assumed that in this specific case, Pyramimonas scales still remain in the lysosome, even after acquiring the Nephroselmis symbiont. Incidentally, when it engulfs Nephroselmis, the latter also undergoes a reduction in its structures, which are digested, leaving remnants such as the (more or less) star-shaped scales of Nephroselmis, which also remain inside the lysosome.

There are many mitochondrial profiles throughout the cell, and the authors think they could be sections or pieces of a single large reticulated mitochondrion, so I've represented it that way. The endoplasmic reticulum is distributed loosely throughout the cell. The article refers to "rough endoplasmic reticulum" that "extends beneath the cell surface," which implies the existence of a smooth endoplasmic reticulum. In other illustrations, I've represented both arrangements of endoplasmic reticulum, but frankly, in this illustration, I was just too lazy (besides, the image was going to become even more oversaturated), so I've left it simply as "endoplasmic reticulum."

And now, the symbiont. Earlier I mentioned that Hatena arenicola literally engulfs the symbiont Nephroselmis. How do the authors know that it actually becomes a symbiont and isn't merely a hijacking of structures and eventual death of the ingested organism? Well, because the symbiont Nephroselmis literally grows inside Hatena arenicola. It's true that it loses several structures, such as flagella, endoplasmic reticulum, and the scales on its cell surface, but in return, it undergoes modifications in its eyespot, its chloroplast grows to almost occupy most of the space in the Hatena arenicola cell, and it develops more pyrenoids, because originally the symbiont only has one. 

This is a response to a symbiotic adaptation in which it must obtain energy from the sun through photosynthesis, but no longer solely for itself, but also for the host (Hatena arenicola). Hence, it develops more chloroplasts, eyespots, and pyrenoids: to generate more energy for both organisms. In exchange, Hatena arenicola loses its feeding apparatus, as it now obtains the energy it needs to live from the photosynthesis of its symbiont. What does the symbiont gain from this? Well, I suppose it gains protection from Hatena arenicola, since it is "covered" by the host.

I should mention that the symbiont's cytoplasm is preserved, although it is called "vestigial cytoplasm." It's not very noticeable in the illustration, but I've drawn it there. Even under a microscope, it's not very visible because most of the symbiont's cytoplasmic space is occupied by the chloroplast itself, which in the article is simply called a "plastid." The life cycle diagram only shows the chloroplast, but keep in mind that in reality, it's not just the chloroplast that exists; it's actually located within the vestigial cytoplasm.

The symbiont's pyrenoids have some invaginations of the chloroplast's thylakoids. I've represented these invaginations as slight convex curves. I haven't shown the thylakoids themselves. The pyrenoids are surrounded by starch sheath, as is common for those who have read the protist posts to date. The symbiont also retains the reticulated mitochondrion, with flat, often degraded cristae (which is why I've represented the cristae as small elliptical spots distributed along the symbiont's mitochondria). The symbiont's nucleus is also preserved, located face-to-face with the nucleus of Hatena arenicola. There are also sacs that resemble those of a Golgi apparatus, but it is thought to be in an inactive or degraded form since it has no associated vesicles. The eyespot, of course, located where the feeding apparatus would be, is conspicuous and made of a single-layered sheet of osmiophilic granules. The eyespot is located beneath the chloroplast membrane.

In the illustration of the symbiont state, I have depicted the symbiont's chloroplast in its most massive form, occupying almost the entire cell space. In the illustration of the non-symbiont stage, the Hatena arenicola structures that do not belong to the symbiont are more clearly visible. Additionally, the feeding apparatus is present, which is actually a microtubular network made of two parts: transverse tubular rings (shown here in pink), and longitudinal microtubules arrayed in a single layer (shown here in yellow). 

Obviously, these are not the actual colors; I represented them this way to make them stand out against the blue background. Within the microtubular skeleton of the feeding apparatus, there are several electron-opaque granules, some large and elongated (light gray), and others smaller, granular, and pigmented (i.e., darker). I've represented both types, but I don't think I've managed to distinguish between them well, and they become barely visible with the colors I used for the feeding apparatus. Oh well, I never passed color theory.

As always, remember that the colors used in these illustrations are more for educational purposes than to accurately represent reality. My ribs are hurting, so I'll stop writing here.

Cryptomonas tetrapyrenoidosa Skuja 1948

I consider this illustration special because my main source for drawing Cryptomonas species is usually the illustrations already in Clay (2015); you can see that my inspiration clearly comes from there. But there isn't a previous illustration of this species, only micrographs that don't provide much information. You could say this is one of my first Cryptomonas illustrations that "almost came from nowhere," except for the text and the limited photographic information available. Yes, this is a paragraph where I declare that I'm proud of what I'm doing.

The illustrations are free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

This species belongs to the family Cryptomonadaceae, order Cryptomonadales, class Cryptophyceae (commonly called "cryptomonad algae"). You know where this is going: cryptomonad algae are then included in the subphylum Rollomonadia, phylum Cryptista, subkingdom Hacrobia, kingdom Chromista. 

The kingdom Chromista is related to the clade Archaeplastida, which includes algae that are relatives and ancestors of plants. You might also encounter another classification, where the phylum Cryptista is included in the clade Pancryptista, which is related to Archaplastida, and both form the large CAM clade. But that's not really important; the point is that Cryptomonas tetrapyrenoidosa is another distant relative of plant ancestors.

The information written here, as well as the illustrations themselves, were based on the following sources:

• "CCAP 979/26. Cryptomonas tetrapyrenoidosa". CCAP s.f. Culture Collection of Algae and Protozoa.
• "Chapter 18 - Cryptomonads". Brec L. Clay, 2015. Freshwater Algae of North America (Second Edition). Academic Press.
• "Cryptomonas tetrapyrenoidosa". Protist Information Server 2018.
• "Cryptomonas tetrapyrenoidosa Skuja 1948". M. D. Guiry in AlgaeBase. 2022.
• "Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea". Bomi Choi, Misun Son, Jong In Kim, Woongghi Shin. Algae, 28(4): 307-330. 2013. DOI: 10.4490/algae.2013.28.4.307

I drew this organism because it had a very long name. Which also gives many clues about its appearance: it has four pyrenoids, two in each chloroplast. Unfortunately, this isn't always the case; the number of pyrenoids can range from 6 to 7. It also has starch grains throughout the cell. By the way, C. tetrapyrenoidosa has two chloroplasts.

Dimensions: according to Clay (2015): 20–60 µm long, 10–27 µm wide, 5–17 µm deep. According to Protist Information Server (2018): 16–25 µm long, 8–13 µm wide, 7–12 µm thick. According to Choi et al. (2013): 16–22 µm long. Hmm, several dimensions to consider.

The name in Choi et al. (2013) should be noted that refers to Cryptomonas tetrapyrenoidosa (Skuja) Hoef-Emden et Melkonian 2003, a name whose equivalence to C. tetrapyrenoidosa Skuja, 1948, the species I have represented here, is uncertain.

According to Protist Information Server (2018), the species has two refractile bodies in the cell center. I am unsure if this term is equivalent to "maupas bodies," as they are technically the same in behavior: two structures found in several species (not only Cryptomonas, but also Chilomonas) that reflect light, hence their white and shiny appearance. However, I have decided to retain the term "refractile bodies" because, let's be honest, I am not an expert on this either. In Clay (2015) Figure 6G, two white oval-shaped circles can be seen in the cell center, which I consider micrographic visual evidence of these structures.

In Clay (2015) Figure 9A, there is an electron micrograph of the cell exterior of C. tetrapyrenoidosa which, thankfully, provides sufficient visual information about the shape of the vestibulum, the flagellar insertion, and the stoma location within the furrow. I have attempted to represent it somewhere between reality (that Figure 9A) and a more "simplified" way within the context of my illustration. I hope this is clear. In the illustration, I refer to the thin black line ending at the stoma as the "furrow," but the rest of the groove (dark gray) surrounding that black line would also be part of the "furrow." My intention was to depict the furrow as a groove-like structure with depth. I don't think I achieved that goal very well, to be honest.

Of course, there is a gullet, which has ejectisomes surrounding it. I don't know the exact arrangement, but I decided to use three rows of ejectisomes because that seems to be "the standard" in Cryptomonas species, according to the Protist Information Server (2018). But assume there can be more. Hey, while I'm at it, did you notice I used a different brush for the ejectisomes? IbisPaint has a special brush that you can temporarily unlock by watching an ad, and it draws like 3D beads. I thought it wouldn't look good, but I already tried it on the Cryptomonas erosa illustration and it turned out great, so I think I'll keep using it for a while longer.

The color is almost speculative, since in the Protist Information Server (2018) the cells appear bright green, but I've illustrated some Cryptomonas species before (not that many, but you get the idea) and they're always around a brownish color, so that's the color I decided to use for this illustration. They're also represented that way in CCAP (n.d.).

Regarding the flagella, their dimensions are almost speculative; I drew them by roughly estimating their size relative to the cell size in Clay (2015) Figure 9A. This time, unlike other species I have already illustrated, I am certain of the arrangement and shape of the mastigonemes on the flagella, since Kugrens et al. (1987) directly mentions that C. tetrapyrenoidosa has type I flagella. And this consists of: the long (dorsal) flagellum has two opposing rows of mastigonemes, each with a single terminal filament. The short (ventral) flagellum also has a single row of mastigonemes, each with two terminal filaments of different lengths. Additionally, there are approximately three terminal hairs at the end of the dorsal flagellum.

Both the mastigonemes and the additional filaments and hairs can only be seen with an electron microscope. Don't expect to see them with a light microscope. Even the flagella are sometimes difficult to see with a light microscope. I almost forgot: both flagella are located on the right side of the vestibule. That's from a dorsal view. In a ventral view, they appear to be on the left, but that's just an illusion!

Additionally, according to Clay (2015), Cryptomonas species generally have two nucleomorphs between the nucleus and the pyrenoids. Unfortunately, C. erosa does not have pyrenoids, so I have drawn the nucleomorphs above the nucleus. The nucleomorphs in this illustration are therefore speculative.

The shapes of the single reticulated mitochondrion, Golgi apparatus and endoplasmic reticulum are also speculative. In the case of the mitochondrion, it's a predicted reticulated shape based on what Santore and Greenwood (1977) explains, where it's mentioned that Cryptomonas has a single mitochondrion with numerous branches distributed throughout the cell, concentrated in areas like the gullet. It's assumed that these mitochondrial branches should have different thicknesses in various sections, but in my drawing, the width of these branches is almost uniform.

Will there be rule 34 of my OC?

I should be doing other things right now. Especially since I also have to study some user guides for special cameras. Because, as I mentioned in a previous post, next week I'll be going on a trip that could lead to my first real job. I'm excited about that, as well as about reaching 20 illustrations. I need to hurry and upload these files online and keep expanding my reach.

Cryptomonas erosa Ehrenberg 1832

And what better way to do it than with this song playing in the background?

(ﾟo´(┗┐ヽ(╰ , ╯ )ﾉ

Illustration 17 in the series. I finished it yesterday, April 8th. The illustrations are free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

I was in an art course that had some interesting promises, but I didn't have the time. Nah, it actually bored me. I say that even though I'm not exactly the best person to claim I know anything about art, because it's clear I'm terrible at choosing colors, and I think there's a way I could improve my illustrations. Honestly, I didn't have the time, and I had to travel far away, and besides, I have more important projects to attend to. Did you know that probably? No, that most likely, sometime next week, I'll be heading off to what looks like my first paid job. I won't give any more details except that it involves invertebrates, but I'm excited about what it might mean.

Anyway, in this post, I'm going to talk about Cryptomonas erosa. I'm too lazy to explain the Taxonomy again, so I'll just copy and paste from someone else. I'll probably do the same to save myself some mental effort. This species belongs to the family Cryptomonadaceae, order Cryptomonadales, class Cryptophyceae (commonly called "cryptomonad algae"). You know where this is going: cryptomonad algae are then included in the subphylum Rollomonadia, phylum Cryptista, subkingdom Hacrobia, kingdom Chromista. 

The kingdom Chromista is related to the clade Archaeplastida, which includes algae that are relatives and ancestors of plants. You might also encounter another classification, where the phylum Cryptista is included in the clade Pancryptista, which is related to Archaplastida, and both form the large CAM clade. But that's not really important; the point is that Cryptomonas erosa is another distant relative of plant ancestors.

The information written here, as well as the illustrations themselves, were based on the following sources:

• "Chapter 18 - Cryptomonads". Brec L. Clay, 2015. Freshwater Algae of North America (Second Edition). Academic Press.
• "Cryptomonas erosa Ehrenberg, 1831". Martin Kreutz. Real Micro Life, 2021.
• "Cryptomonas erosa Ehrenberg 1832". M. D. Guiry in AlgaeBase. 2022.
• "Cryptomonas erosa/ovata/phaseolus". Part of; Steckbriefe der Phytoplankton-Indikatortaxa. Kasten J., Kusber W.-H., Riedmüller U., Tworeck A., Oschwald L. & Mischke U. Berlin: Botanic Garden and Botanical Museum Berlin, Freie Universität Berlin. –  177 pp., ISBN 978-3-946292-28-9, https://doi.org/10.3372/spi.01. 2018.

The cells are oval or slightly elliptical, 13 to 45 µm long and 6 to 26 µm wide. They have two chloroplasts without pyrenoids, like Cryptomonas phaseolus, but the difference in that respect is the cell size. More important is the color: the chloroplasts in Cryptomonas erosa range from brown to yellowish to greenish. I have chosen to represent it as an intermediate point between brown and yellowish (with a small green base, although I don't think it's very noticeable).

Another characteristic is that the dorsal side is significantly convex, while the ventral side is only slightly convex, or even flat. In the micrographs by Kreutz (2021), I don't see a large convexity (outward curvature) on the dorsal side, but it does appear to be more curved than the ventral side.

Another difference from C. phaseolus is that C. erosa has maupas bodies.

The contractile vacuole is located anteriorly, next to the flagellar insertion point. From a ventral view, it would appear to the right of the flagellar region. Dorsally, it would appear on the left side.

In C. erosa, the gullet is covered with ejectisomes (which shouldn't be surprising if you know about Cryptomonas species), and it extends up to half the length of the cell. It doesn't go beyond that half. The gullet connects to the outside through the vestibulum. The starch grains are distributed throughout the cell and have polygonal or oval shapes.  Since it has the cryptomorph shape, I have represented the furrow as a complex one (with the presence of a stoma). You can find out more about this in the post on Cryptomonas obovata.

Kreutz (2021) mentions that the flagella are the same length, but both there and in Clay (2015) Figure 5D, they are depicted as unequal. I have decided to represent them as very similar in size, such that the dorsal flagellum is slightly longer.

The flagella of C. erosa are represented as if they had type 1 flagella according to Kugrens et al. (1987). This decision is speculative. I haven't found any information on what they actually look like; I assume they correspond to type 1, because it's the most common type (or the one that should be the most common) according to Kugrens et al. (1987). In this type 1 flagella, the long (dorsal) flagellum has two opposing rows of mastigonemes, each with a single terminal filament. The short (ventral) flagellum also has a single row of mastigonemes, each with two terminal filaments of different lengths. Additionally, there are approximately three terminal hairs at the end of the dorsal flagellum.

Both the mastigonemes and the additional filaments and hairs can only be seen with an electron microscope. Don't expect to see them with a light microscope. Even the flagella are sometimes difficult to see with a light microscope. I almost forgot: both flagella are located on the right side of the vestibule. That's from a dorsal view. In a ventral view, they appear to be on the left, but that's just an illusion!

Additionally, according to Clay (2015), Cryptomonas species generally have two nucleomorphs between the nucleus and the pyrenoids. Unfortunately, C. erosa does not have pyrenoids, so I have drawn the nucleomorphs above the nucleus. The nucleomorphs in this illustration are therefore speculative.

The shapes of the single reticulated mitochondrion, Golgi apparatus and endoplasmic reticulum are also speculative. In the case of the mitochondrion, it's a predicted reticulated shape based on what Santore and Greenwood (1977) explains, where it's mentioned that Cryptomonas has a single mitochondrion with numerous branches distributed throughout the cell, concentrated in areas like the gullet. It's assumed that these mitochondrial branches should have different thicknesses in various sections, but in my drawing, the width of these branches is almost uniform.

I want to remind you that this mini visualization of the ventral view of C. erosa is simplified, indicating the parts most potentially visible under an optical microscope.

I think that's all I had to say about this organism. I have another illustration pending upload, which I'll also post about. I'm excited because I'm about to reach my goal of 20 illustrations. I don't want to think too much about having to do 100 because I feel like it will discourage me. Fortunately, things in my life have improved slightly.

Cryptomonas phaseolus Skuja 1948

And well, this would be the third Cryptomonas species I've illustrated. I don't know whether to celebrate it as some kind of major event, but oh well. Actually, I'm writing this paragraph while watching an episode of standard Roncom, and I don't think I'll write any more. The goal is simply to get this post started.

Well, I think I've finally decided to write a little. In this post, I'll talk about Cryptomonas phaseolus. It's a species whose specific epithet makes me laugh; it's like they're talking about beans. The illustrations are free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

This species belongs to the family Cryptomonadaceae, order Cryptomonadales, class Cryptophyceae (commonly called "cryptomonad algae"). You know where this is going: cryptomonad algae are then included in the subphylum Rollomonadia, phylum Cryptista, subkingdom Hacrobia, kingdom Chromista. The kingdom Chromista is related to the clade Archaeplastida, which includes algae that are relatives and ancestors of plants. You might also encounter another classification, where the phylum Cryptista is included in the clade Pancryptista, which is related to Archaplastida, and both form the large CAM clade. But that's not really important; the point is that Cryptomonas phaseolus is another distant relative of plant ancestors.

The information written here, as well as the illustrations themselves, were based on the following sources:

• "Chapter 18 - Cryptomonads". Brec L. Clay, 2015. Freshwater Algae of North America (Second Edition). Academic Press.
• "Cryptomonas erosa/ovata/phaseolus". Part of; Steckbriefe der Phytoplankton-Indikatortaxa. Kasten J., Kusber W.-H., Riedmüller U., Tworeck A., Oschwald L. & Mischke U. Berlin: Botanic Garden and Botanical Museum Berlin, Freie Universität Berlin. –  177 pp., ISBN 978-3-946292-28-9, https://doi.org/10.3372/spi.01. 2018.
• "Cryptomonas phaseolus Skuja 1948". M. D. Guiry in AlgaeBase. 2022.
• "Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea". Bomi Choi, Misun Son, Jong In Kim, Woongghi Shin. Algae, 28(4): 307-330. 2013. DOI: 10.4490/algae.2013.28.4.307

I hope I don't take too long with this species. 

According to Clay (2015), it is the smallest Cryptomonas species, measuring 8 to 13 µm in length and 5 to 8 µm in diameter. It has an ellipsoidal shape in lateral view and an oval shape in cross-section. The anterior end has a rounded protrusion just above the flagellar insertion site, while the posterior end is slightly narrower. Oh, and it has two chloroplasts without pyrenoids. Graphically, as shown in Clay (2015) Figure 5C, it has several starch grains distributed throughout the cell. Classic cryptomonad structures are also present, such as the gullet covered with ejectisomes and the furrow. Since it has the cryptomorph shape, I have represented the furrow as a complex one (with the presence of a stoma). You can find out more about this in the post on Cryptomonas obovata.

That is all the formal information available about the species. The shapes of the single reticulated mitochondrion, Golgi apparatus, endoplasmic reticulum, contractile vacuole, mastgigonemes/terminal hairs and nucleomorphs are purely speculative. In the case of the mitochondrion, it's a predicted reticulated shape based on what Santore and Greenwood (1977) explains, where it's mentioned that Cryptomonas has a single mitochondrion with numerous branches distributed throughout the cell, concentrated in areas like the gullet. It's assumed that these mitochondrial branches should have different thicknesses in various sections, but in my drawing, the width of these branches is almost uniform.

The flagella of C. phaseolus are represented as if they had type 1 flagella according to Kugrens et al. (1987). This decision is equally speculative, and it doesn't so much affect the flagella as the nature of the mastigonemes. I haven't found any information on what they actually look like; I assume they correspond to type 1, because it's the most common type (or the one that should be the most common) according to Kugrens et al. (1987). In this type 1 flagella, the long (dorsal) flagellum has two opposing rows of mastigonemes, each with a single terminal filament. The short (ventral) flagellum also has a single row of mastigonemes, each with two terminal filaments of different lengths. Additionally, there are approximately three terminal hairs at the end of the dorsal flagellum.

Both the mastigonemes and the additional filaments and hairs can only be seen with an electron microscope. Don't expect to see them with a light microscope. Even the flagella are sometimes difficult to see with a light microscope. I almost forgot: both flagella are located on the right side of the vestibule. That's from a dorsal view. In a ventral view, they appear to be on the left, but that's just an illusion!

Regarding the two nucleomorphs, apparently, according to Clay (2015), Cryptomonas species generally have two nucleomorphs between the nucleus and the pyrenoids. Unfortunately, C. phaseolus does not have pyrenoids, so I have drawn the nucleomorphs above the nucleus.

Cryptomonas phaseolus (Skuja) Hoef-Emden 2007.

Now, next to the main image, there is another ventral view that represents, in a very simplified way, a strange strain I found in the article by Choi et al. (2013) (Figures 11 G and H): Cryptomonas phaseolus (Skuja) Hoef-Emden 2007. I already checked it on AlgaeBase and it's not listed there as a synonym of Cryptomonas phaseolus Skuja 1948. The morphology is identical to that of C. phaseolus Skuja 1948, except that C. phaseolus (Skuja) Hoef-Emden 2007 does have one pyrenoid per chloroplast (there are two chloroplasts, so there are two pyrenoids). Could it be a synonym of another species that has nothing to do with C. phaseolus Skuja 1948? Who knows? But if you find out anything, let me know in the comments. 

Yes, that uncertainty is why I haven't decided to make a version indicating the parts only for that strain, taxon, or whatever it's called... I was just too lazy, really. Maybe I'll make a version in the future, but don't count on me too much.

I think that's all I have to say. I have to write for the other species. See you.

Falcomonas daucoides (W.Conrad & H.Kufferath) D.R.A.Hill 1991

The first organism drawn this month.

Just a reminder that these images are free to use under a CC BY-SA 4.0 Attribution-ShareAlike 4.0 International license. They are for non-commercial purposes only (if you'd like to discuss this further or use any of these images for a paid cultural project, such as a documentary, please contact me). You must also credit the image creators. "DOTkamina 2026" is more than sufficient.

Hey, I should step out of my comfort zone a bit and draw something else, don't you think? I've been thinking about drawing fish; it's always good to draw fish.

But anyway, I don't want to get off topic. My mom's coming down the door right now, and honestly, I've been really engrossed in playing games, why lie? My excuse is that I've spent a lot of my time on these illustrations I'm presenting in this particular post. I haven't swept the house or cooked anything, so I'm absolutely cooked rn.

I'll give more details about what happens to me later; I hope I survive. I hope it doesn't leave me so discouraged that I abandon writing this post.

Hahaha I came back.

Falcomonas daucoides is a species of unicellular microalga belonging to the class Cryptophyceae. It is therefore a cryptophyte alga, like others I have illustrated previously. More interestingly, it is included in the order Pyrenomodales. This means it is related to the family Pyrenomonadaceae (which includes Pyrenomonas helgolandii and Pyrenomonas ovalis, which I illustrated some time ago). Falcomonas daucoides is not in that family, by the way, but in Hemiselmidaceae.

More broadly, the class Cryptophyceae is included in the superclass Cryptomonada, and this in the phylum Cryptista, clade Pancryptista. The latter is related to the clade Archaeplastida, which includes the ancestors and close relatives of plants (Viridiplantae). F. daucoides is common in marine habitats, according to Kugrens et al. (2000).

I almost gave up on drawing Falcomonas daucoides because I couldn't find much information about it. The main sources I used to create these drawings and the information are:

• "Chroomonas and other blue-green cryptomonads". David R. A. Hill 1991. 
• "Order Cryptomonadida". Paul Kugrens, Robert E. Lee and David R. A. Hill. In: J. J. Lee, G. F. Leedale & P. Bradbury (ed.), An Illustrated Guide to the Protozoa. 2nd ed. 2000. p. 1111–1125.
• "Periplast development in Cryptophyceae III. Development of crystalline surface plates in Falcomonas daucoides, Proteomonas sulcata [haplomorph], and Komma caudata". Steve Brett and Richard Wetherbee. Protoplasma, 1996. 192: 49-56.

There isn't much to say. It has two flagella, as is common in several cryptomonads. I couldn't find information about the nature of the mastigonemes on the flagella, so I assumed they must follow the form of type 1 mastigonemes according to Kugrens et al. (1987), because it is (or should be) the most common type. In this type, the short flagellum has a single row of mastigonemes with two terminal hairs (one longer than the other), while the long flagellum has two rows of mastigonemes, each with a single terminal hairs. Additionally, at the end of the long flagellum, there are three terminal hairs.

The forms of the mitochondrion, endoplasmic reticulum, and Golgi apparatus are speculative. There is only a single reticulated mitochondrion, as is assumed to occur in all cryptomonads. In the case of the Golgi apparatus, it is indeed visible in Hill (1991) Figure 35, but the image quality is so poor that its shape is not discernible. Hill (1991) also mentions that the Golgi apparatus is located anteroventrally. For F. daucoides, I found no information on the existence of a contractile vacuole, but according to Clay (2015), cryptomonads possess at least one, so I have included it. The organism also has a nucleus with a nucleolus and a nucleomorph located above the pyrenoid (located anteriorly). This is a good time to mention that I forgot to indicate the anterior and posterior portions, but they are essentially above and below in the lateral view, respectively.

Things get interesting with the pyrenoid. It is covered with a starch sheath, but the important point is that it is almost divided by an inlet of the cytoplasm, which is called the "cytoplasmic tongue." Regarding the vestibulum (the depression on the cell surface from which the flagella emerge, and which connects to the furrow-gullet digestive complex), it is accompanied by the vestibular plate, located within the vestibule margin, to the left of the flagellar emergence site. The surface of the vestibular plate is composed of triangular crystalline subunits.

The furrow-gullet complex is interesting. The furrow is simply the long depression that runs from the vestibulum posteriorly, in the case of F. daucoides, to approximately the middle of the cell. The "gullet" is not described as a true gullet; Kugrens et al. (2000) refers to it as a sac-like gullet. Another interesting feature is the presence of two bands made of microtubules: the mid-ventral band (MVB), which originates posteriorly and extends toward and along the left fold of the furrow, and the rim fiber, located on the right fold of the furrow. You'll probably notice that in the illustration, the rim fiber appears to be on the left and the MVB on the right. This is an illusion of orientation, as the organism depicted is "looking" at us ventrally, so its right side appears to be on the left, and vice versa.

The chloroplast has thylakoids that are slightly arranged in pairs, but I haven't represented that very well. The chloroplast is located on the dorsal side of the cell. The chloroplast seems to occupy mainly the "main body" of the cell and is absent from the posterior part, where the cell's "tail" is located. By "tail," I mean the posterior end that gives the organism a comma-like appearance. The chloroplast contains Cr-phycocyanin 569, which gives it a blue-green color. That's why in my illustration the tones are mainly blue-green (almost turquoise). Keep in mind, however, that the colors are primarily for illustrative purposes and don't correspond to reality.

According to Brety and Wetherbee (1996), the plasma membrane (or plasmalemma) is sandwiched between the two layers of the periplast: the surface periplast component SPC (made of hexagonal plates, each composed of minute subunits, with disordered minute subunits in the spaces between these plates) and the inner periplast component IPC. Few details are given about the IPC; Kugrens et al. (2000) imply that the IPC plates are also hexagonal.

Finally, I must mention the ejectisomes, which appear to be large in F. daucoides. The furrow is lined with 2 to 4 rows of ejectisomes. I have chosen to represent only two rows.

Well, I think that's all there is to say.

Klosteria bodomorphis Mylnikov & Nikolaev 2003

Klosteria bodomorphis is a free-living protist belonging to the Neobodonidae family, which, as I'll explain later, is related to dangerous kinetoplastid organisms... well, it's not that surprising, but still.

These drawings are free to use and you probably found them on Wikimedia Commons. They are licensed under CC BY-SA 4.0 Attribution-ShareAlike 4.0 International. Free use for non-commercial purposes. You also have to give credit every time you use an image. "DOTkamina 2026" is fine, I think.

Sources: formally just one: "The taxonomic position of Klosteria bodomorphis gen. and sp. nov. (Kinetoplastida) based on ultrastructure and SSU rRNA gene sequence analysis" by Sergey I. Nikolaev, Alexander P. Mylnikov, Cedric Berney, Jose Fahrni, Nikolai Petrov and Jan Pawlowski, Protistology 3 (2), 126-135 (2003)... or simply Nikolaev et al. (2003). It's literally the article where this species is described. Although, to be honest, it was a bit complicated because there were strange concepts I didn't quite understand. That's why I also consulted this book chapter on kinetoplastid microanatomy: "Kinetoplastea" by Gibson, W. (2016).

So... Klosteria bodomorphis belongs to the family Neobodonidae, order Neobodonida, subclass Metakinetoplastina, in the class Kinetoplastea. I don't know what is more unnerving: that Kinetoplastea is included in the phylum Euglenozoa (meaning they are distantly related to the famous microalgae Euglena), or that along with Neobodonida, which includes free-living species that eat bacteria, it encompasses other clades where the titans, the horror of many, reside, such as Trypanosoma and Leishmania (in the order Trypanosomatida).

But with Klosteria bodomorphis, you have nothing to worry about. This is a free-living organism that was isolated from samples taken from the Baltic Sea shoreline, near the town of Kloster, Germany, in December 1994. It's an organism that feeds on bacteria—which ones? I don't know. In the illustration, I depict a specimen of Aerobacter (Klebsiella) aerogenes as prey, and within its food vacuoles, I have drawn amorphous pinkish blobs representing partially digested bacteria of that species. The reason for choosing this specific species is that Nikolaev et al. (2003) used this bacterium as a food source in laboratory culture. However, it is unknown exactly which bacterial species or clades it might consume in nature.

But focusing on its anatomy, I'll begin by saying that it has two heterodynamic flagella: the anterior one measures 12 µm and the posterior one 17 µm. At the end of each flagellum are short, tapering tips known as acronemes. The anterior flagellum is covered with mastigonemes measuring 2 to 2.5 µm. Both flagella are covered by a layer of condensed glycocalyx, but I haven't depicted that.

You already know the typical flagellar configuration: 9+2 (nine doublets of microtubules surrounding two central single microtubules), enclosed by the plasma membrane. More generally, flagella "emerge" from the cytoplasm. In Klosteria bodomorphis, the flagella emerge from a kind of "depression" on the cell surface, surrounding the lower portions of the external flagella. This "depression" is known as a "flagellar pocket," which is shallow and located subapically. According to Nikolaev et al. (2003), flagellar pockets containing four flagella have been found... which is quite disturbing.

Equally disturbing is the microtubule system identified using electron microscopy, which I have represented more accurately based on the text by Gibson (2016). First, it's worth noting that the flagella, or rather, the 9+2 configuration, originate from the basal bodies. The basal bodies are also anchored by flagellar roots (abbreviated "fr" in the image). Hell yeah, fr!

The flagellar root of the anterior flagellum (that is, the one that originates from the basal body of the previous flagellum) is made of 2 to 3 microtubules and then gives rise to the dorsal submembrane band (simply called the "dorsal band"), which is made of at least 25 microtubules. This band, according to Gibson (2016), extends along the entire dorsal side of the cell.

Simultaneously, the flagellar root of the posterior flagellum emerges from the basal body of the posterior flagellum. This root is composed of six microtubules and extends posteriorly (presumably towards the ventral side of the cell) to form the ventral submembrane band (or simply the "ventral band"), composed of 27 microtubules, which runs along the entire ventral side of the cell.

Between the basal bodies are two microtubules that connect them, which I have labeled as the "fibrillar connection" in the illustration. Another interesting microtubular structure is the so-called "MTR band" (microtubular reinforced band), composed of four to five microtubules. It originates at the surface of the flagellar pocket and extends to the cytopharynx, where it is supplemented by additional microtubules. I have depicted two additional microtubules in the illustration, but Nikolaev et al. (2003) do not specify the actual number. I chose that number because I think I see two more than the 5 of MTR (I hope there are 5) in Illustration 16, but in Illustrations 14 and 15 I think I see more... so I don't know xd.

The shapes of the bands are purely illustrative, but their placement is based verbatim on Nikolaev et al. (2003), and primarily visually on Gibson (2016) Figure 3, and Frolov et al. 2021.

The organism has a cytostome (the "mouth" through which food, bacteria, enters), which is essentially the opening through which food enters. This opening connects to the rest of the invagination, the cytopharynx, a tunnel-like structure measuring 1.8 to 2.3 µm. The lower part of the cytopharynx is surrounded by vesicles. This can be called the "cytostome-cytopharynx complex," and it is simply a very complex cellular feature for phagocytosis, since it is in the cytopharynx that food is packaged into food vacuoles. These vacuoles are directed toward the hind part of the cell (the posterior part).

The organism also has a Golgi apparatus, which is located near the basal bodies. The shape of the Golgi apparatus in the illustration is more schematic than realistic. The nucleus with nucleolus, obviously (although I haven't depicted the nucleolus in this image), "lies at the level of the bottom of the flagellar pocket and at the end of the cytopharynx," according to Nikolaev et al. (2003). They also say that the nucleus is vesicular. I don't know exactly what that means; in (cancer) cytology, it refers to cells with loosely packed chromatin, which under the microscope appear to have nothing inside... but I don't know. In my illustration, you'll see that the nucleus has some dark ornaments in the center and others surrounding it. You can assume the one in the center is the nucleolus. This decision was based on Nikolaev et al. (2003): Figure 17. Around the nucleus is the endoplasmic reticulum, both smooth and rough, and its shapes and existence are speculative (I assume they must exist because they are common in all eukaryotic cells).

The mitochondrion have an almost speculative shape. As can be seen in Nikolaev et al. (2003): Figure 18, appears to extend across a significant portion of the cell. The authors debate whether it is truly a single structure or if it might be more branched. I have chosen to depict it as slightly branched. The authors describe the mitochondria as having discoid cristae. The cristae are invaginations of the inner mitochondrial membrane, and their discoid form refers to the fact that these invaginations are shaped like discs with small "peduncles" (pedicellate, see Pánek et al. (2020): Figures 2A and 2F) when the section is longitudinal, and like sausages or cylindrical "bacilli" when the section is transverse. I have represented them almost as if they were seen in transverse section and pedicellate, in the mitochondrion of my illustration.

Now, I mentioned earlier that Klosteria bodomorphis belongs to the large order Kinetoplastea, and you'll read that the most important characteristic of this group is the kinetoplast, a mass of DNA arranged in maxicircles and minicircles (Wang et al. 2025), located within the mitochondria in a specific region, usually near the basal bodies. But this isn't a mandatory feature for all kinetoplastids; it's actually a structure that is repeated in some, and especially studied in species that are parasitic to humans. For other kinetoplastid species, we can speak of "kinetoplasty," a term that encompasses other forms of organization of kinetoplastid DNA (kDNA).

One such form is pankinetoplasty, described as bundles of kDNA isotropically distributed throughout part or all of the mitochondrial lumen (Gibson 2016: Figure 1i)... think of it as more or less elongated groups of kDNA that are present throughout, or almost throughout, the interior of the mitochondrion. In cell biology, "isotropic" refers to the fact that, in any part of a structure, the properties (I suppose physical, shape, optical, chemical, or whatever) will be more or less similar (New World Encyclopedia n.d.).

According to Nikolaev et al. (2003), Klosteria bodomorphis has little DNA within the mitochondrion that can be interpreted as kDNA, and if so, the most appropriate classification would be pankinetoplasty. The reason they give is that the kDNA fibers do not occupy a very prominent space within the mitochondria. The pankinetoplast (and any other type of kinetoplast, really) should appear as dark spots or aggregates within the mitochondria under an electron microscope. I only manage to observe this more or less in Nikolaev et al. (2003): Figures 16 and 18. I imagine these small spots are slightly darker than the cristae... I have represented the supposed "pankinetoplast" of K. bodomorphis as more or less elongated spots, somewhat distributed throughout the mitochondrion... but it is possible that in reality they are even smaller, more insignificant, less observable or noteworthy spots.

Finally, storage substance granules measuring 0.10 to 0.35 µm in diameter have also been observed in Klosteria bodomorphis. These, along with symbiotic bacteria, one of the most cursed aspects of the organism, measure 0.3 to 0.6 µm in diameter. The authors noted cell division in some of these bacteria, and I have indeed depicted such bacterial division in my illustration.

However, this isn't the end. I've forgotten about the trichocysts. In Klosteria bodomorphis, these are elongated and cylindrical. Length: 1.2 to 1.9 µm, diameter: 0.15 µm, with an internal rod of 0.6 to 0.77 µm, which I've represented as a darker area within the trichocysts. Nikolaev et al. (2003) mention that they are located near the ventral side of the flagellar pocket. I suppose I've erred here because I've depicted them more dorsally, near the ventral band. In fact, this is clearer in the image attached next to the main one, titled "Close-up of the flagellar zone," (the image above, without labels) which is entirely inspired by Nikolaev et al. (2003): Figure 13. So... feel free to discuss whatever you like in the comments. I'd be happy to see corrections and possible improvements. My hand hurts right now, and I have a trip planned where I'll be dragging myself along to see if my final project makes any progress, so lol.

There are 8 to 9 trichocysts arranged in a row, also known as extrusomes. This group is known as a "trichocyst battery." In the main image, only two trichocysts are visible, but that doesn't mean there are only two... they're assumed to be viewed from the side, and those two are "covering" the others.

I guess that's all I have to say. I wasn't expecting to do this illustration, because the organism seemed strange to me. I don't even know how I came across this organism; I think I was reading about trichocysts for a previous illustration. I don't know, I just got a sudden urge and said, "Let's do it, or I'll die." Or maybe it was out of pride. Or perhaps it was out of morbid curiosity to see if I'll finally reach 100 illustrations, or even 20. That number 20 looks pretty promising.