Andalucia godoyi E.Lara, Chatzinotas & A.G.B.Simpson 2006

I'll confess I'm pretty burned out because I just finished writing and publishing about Cryptomonas borealis (well, that was on 30th May) but I at least wanted to get started on this species. At this point, you might be wondering, "Why this species?" Well, don't overthink it; I didn't either when I chose it. It was supposed to be a simple one, in theory. But the microtubular part was a real headache for a few days. I even almost gave up on continuing these illustrations.

A peaceful screamer reminder: The following illustrations depict Andalucia godoyi E.Lara, Chatzinotas & A.G.B.Simpson 2006, as the name is recorded on AlgaeBase. The images are free to use and are also available on Wikimedia Commons. Of course, commercial use of these images is not permitted, nor is their use without proper attribution. "DOTkamina (2026)" is sufficient. I guess that's it. gng goodbye ʕ•̫͡•ʕ•̫͡

First, some context: Andalucia godoyi belongs to the family Andaluciidae, suborder Andalucina, order Jakobida, class Jakobea. 

Damn, I'm already so lazy about having to write this, haha. I have to.

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Hmm, let's see: formally, the class Jakobea only includes the order Jakobida. I suppose that's why these organisms are known as "jakobids," regardless of whether they're referring to the order or the class. Jakobea, along with Malawinonadea, is characterized by having a posterior cilium in a ventral feeding groove, which gives a "scooped-out" appearance, and that's why both taxa were included in the Excavata group (Lewis and Brodie 2007).

The class Jakobea would be included in the subphylum Eolouka, and this in the phylum Loukozoa. According to Mindat, the phylum Loukozoa includes Jakobea along with the subphylum Neolouka, the class Malawimonadea, and the class Tsukubea. Leukozoa would be related to the order Ancyromonadida. Mindat does not consider Eolouka; that's from AlgaeBase.

According to AlgaeBase, the matter is more complicated: Leukozoa would include the subphyla Eolouka, along with Kinetomonada, Metamonada, and Neolouka. The subphylum Eolouka would include the classes Jakobea, Kinetomonadea, and Tsukubea.

In any case, the phylum Loukozoa is included within the infrakingdom Excavata, which is in the kingdom Protozoa, and from there to the domain Eukaryota.

I haven't researched it much, but I would think that the connections between species within these clades are more molecular than morphological. I haven't found much information about what makes jakobids stand out. Wikipedia mentions a number of characteristics, but I don't think they are truly diagnostic enough to distinguish jakobids from the rest. Namely:

Jakobids possess two flagella, inserted at the anterior end of the cell, and, like other organisms in the Excavata group, they have a ventral feeding groove and an associated cytoskeletal support. The posterior flagellum has a dorsal vane and is aligned within the ventral groove, where it generates a current that the cell uses for food intake. The nucleus is generally located anteriorly and has a nucleolus. Most known jakobids have a mitochondrion, also located anteriorly, and different genera have flattened, tubular, or absent cristae. Food vacuoles are located mainly at the back of the cell, and in most jakobids the endoplasmic reticulum is distributed throughout the cell.

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Having said that, I can finally say that the main source I consulted to obtain the information for this blog post, as well as for the creation of the images, was the following: "Andalucia (n. gen.)--the deepest branch within jakobids (Jakobida; Excavata), based on morphological and molecular study of a new flagellate from soil", by Enrique Lara, Antonis Chatzinotas and Alastair G. B. Simpson, 2006. J Eukaryot Microbiol. 53(2):112-120 pp. doi: 10.1111/j.1550-7408.2005.00081.x.

Other sources employed in this text and image construction were:

• "Andalucia godoyi (gen. nov.; sp. nov), a novel jakobid-like flagellate isolated from soil, is a representative of a new excavate clade". by Enrique Lara, 2005. In: Molecular analysis of the biodiversity of protists in hydrocarbon-polluted and pristine soils. Thèse Nº 3211 109-122 pp.
• "Jakobida", by Simpson, A. G. B. 2017. In: Archibald, J., Simpson, A., Slamovits, C. (eds) Handbook of the Protists. Springer, Cham. https://doi.org/10.1007/978-3-319-28149-0_6

The "main cell image" or "main illustration", When I use these terms with "main" I will be referring to this image.

See this sh1t drawing? I have to say, it turned out amazing because it's been a while since I last opened those images, and now I have no idea what it's supposed to show.

Well, I'm back now, and I remember what it's about: you see, the main image is divided into three sections. It's best if you look at it from right to left. Yes, I know it would have made more sense to do it from left to right, but that's just how the sketch came out, and well, I've always been bad at organizing things.

In the right-hand section is the main image of the cell of the organism Andalucia godoyi, in lateral view. In the central part, there's a detail of the flagellar apparatus, which corresponds to the anterior surrounding area, where the basal bodies and the beginning of the ventral groove are located. In that diagram of the flagellar apparatus, you'll notice about four black lines, which correspond to cross-sections. The details of these sections are indicated on the left, under "sections details." Let's discuss each part slowly.

Lateral view.

Right part of the main image: diagram of the organism in lateral view. Specifically, where the ventral side is facing left, and the dorsal side is facing right. It also indicates that the side being viewed is the left, and the opposite side (which is not being viewed) would be the right. Okay, this illustration shows the most representative parts of the Andalucia godoyi cell:

Starting with the ventral groove, whose length I don't know, but in the article by Lara et al. 2006, Figs. 2 and 3, it is indicated as being in the middle of the cell, which leads me to interpret that it occupies more or less almost the entire ventral area of ​​the cell; it must be quite long. I also know that its origin is "at the anterior end" because it mentions that the flagella originate above the ventral groove, and the flagella are correctly positioned at the anterior end.

The single mitochondrion is an elongated structure that runs the length of the cell from the anterior end (near the basal bodies of the flagella) to near the posterior end, after encircling the nucleus from above, either from the left or the right side (according to Lara 2005). The mitochondrion has tubular cristae. I don't know if I'm hallucinating or if I'm really bad at protistology, but in the micrographs, the mitochondrion resembles white bean broth, with whitish spots that give it a trypophobic appearance, and I've decided to represent the mitochondrion that way. You can check the original images yourself if you want.

The nucleus is located in the center of the anterior region of the cell. It has a nucleolus located in the center. One particular feature is the presence of an electron-dense spherical organelle attached to the posterior part of the nucleus, which Lara et al. (2006) refer to it as the "paranuclear body," and that's how I've written it in the illustration.

They also mention the existence of a Golgi apparatus, which for some reason they call the "Golgi apparatus dictyosome," and then say that it has "3 to 5 cisternae" (I've drawn it with 3 cisternae), in the anterior part of the cell, "ventrally and to the right of the flagellar apparatus." I have no problem with that, except that "dictyosome" is supposed to be the name for each of the individual cisternae that make up the Golgi apparatus, and in Lara et al. (2006) they mention it as if it were a synonym for "Golgi apparatus." Well, that's my question; I'll leave you to think about it or discuss it in the comments.

Nothing is mentioned about the endoplasmic reticulum. Fortunately, Simpson (2017) mentions that in jakobids, the endoplasmic reticulum is branched throughout the cell. That's how I've represented it. I've avoided (I think I'll do so in future illustrations) distinguishing between the rough and smooth endoplasmic reticulum as two separate parts (this is for the sake of understanding, as eukaryotic cells are taught in schools and colleges, but it gives the mistaken impression that they are two completely separate sub-parts). In any case, you can still distinguish which part would be the rough endoplasmic reticulum because some branches have a higher concentration of ribosomes (those blue dots). Furthermore, I've drawn more ribosomes more dispersed throughout the cell, as should be the case in any standard eukaryotic cell.

In the posterior half of the Andalucia godoyi cell, there are several food vacuoles with digesting bacteria. I've depicted about four of them. And that's all I have to say about them, really.

Flagellar apparatus detail. F2 is the anterior flagellum (and B2 the basal body of F2). F1 is the posterior flagellum (and B1 is... the basal body...... of F1).

And now for the fun part: the flagellar apparatus. In the main cell image (right side), the basal bodies and their respective flagella are only faintly visible. Both flagella are twice as long as the cell itself, and they have the typical 9+2 flagellar arrangement (9 peripheral microtubular doublets surrounding two central singlets). The microtubular structure of the basal bodies isn't mentioned, but I've decided to represent them with the standard 9+0 arrangement (9 peripheral microtubular triplets surrounding an empty center).

With that brief introduction, let's now describe the central part of the illustration, labeled "flagellar apparatus" in a red box. Before proceeding, I should mention that the representations of microtubules and related structures are very "linear." For some structures, Lara et al. (2006) mention the number of microtubules that compose them, but not for others, and in those I have represented them as a single line or as several, but these are speculative decisions made primarily to avoid confusing the observer. It assumes that in reality they could be wider, more diffuse, more complex, etc. Another point: to avoid double terms and confusion, I have decided to use the same terms employed in Lara et al. (2006), so that it can be compared with the illustrations in that work and the terminology they use.

We can discuss the flagellar apparatus in terms of which structures accompany which of the two basal bodies. But first, let's talk about the basal bodies: both measure approximately 550 nm and are separated by an angle of 135º, with a distance of 170 nm between them. There are two thin, crescent-shaped, electron-dense structures that connect the basal bodies. The first is the StC (striated crescent, striated connecting fibre), which is crescent-shaped. The other is the SmC (thin smooth crescent fibre), and according to Lara et al. (2006), it is associated with the dorsal side of basal body 2. Both structures are shown in Lara et al. (2006) Figure 12, but I couldn't distinguish exactly which one was the SmC. I've represented it as being "below" the StC, because that's how it seems to be indicated in Figure 12 of the article. I'm not entirely sure.

Flagellar apparatus detail (right) and sections details (left).

Now, let's talk about the structures that accompany the basal body of the anterior flagellum (B2). There is a dorsal fan (F) of approximately 12 microtubules, which originates near the anterior side of basal body 2 (B2). The dorsal fan connects to B2 via the fan-associated sheet (FA). And that concludes our discussion of B2.

The structure of the basal body 1 (B1) companions is more complex. There are two main microtubular roots (structures that anchor the basal bodies to the cell): microtubular root 1 (R1) and microtubular root 2 (R2).

R1 "originates against the right edge of basal body 1, is directed posteriorly, and consists of a flat row of microtubules." I understand this to mean that the origin of R1 is on the right side of B1. Along with R1, there is a non-microtubular "I" fiber (denoted simply as the letter "I"), associated with the ventral face of R1. Hence, in my illustration, this I structure is "to the left" of R1, which would be interpreted as it being near the ventral side of R1.

There is also a dense "B" fiber (B), which originates against the right ventral side of B1 and continues along the right side of B1, converging with the external portion of R1. I interpret the "B" fiber as being closer to the "I" fiber first, as can be seen in Lara et al. (2006) Figures 14 to 16, although in those micrographs it appears to be further away. Even so, the order would be with the "B" fiber most ventral, then the "I" fiber, and finally R1.

There is also a non-microtubular "A" fiber (A) that initially originates on the dorsal side of B1 (although in my illustration it is not quite on the dorsal side, but rather at a point between the right dorsal and almost ventral sides of B1, so that it is close to Figures 14 and 15 of Lara et al. (2006)), and then it is located near the dorsal side of R1. The "A" fiber has a striated appearance in some sections, which, in my opinion, gives it the appearance of a line with darkened circular spots on top, and that's how I've represented it.

"A singlet microtubule (S) originates in the 'corner' formed by the dorsal side of R1 and the right side of B1." The "S" microtubule is initially connected to the dorsal side of B1 by a singlet-associated fiber (SA), and then extends downwards (posteriorly). This leads me to believe that the SA fiber only seems to exist when it connects the S microtubule to the dorsal side of B1, and that's why in the illustration it only appears near B1, as if it were on top of the "S" microtubule. I hope it's noticeable, although it's already an eyesore for me. Duh...

In addition to R1, there is microtubular root 2 (R2). It originates near the left side of B1 and extends posteriorly. It is made of 7 microtubules. It is accompanied by the non-microtubular "C" fiber (C), which is on the dorsal side of R2. As I can see in Lara et al. (2006) Figure 13, the C fiber appears to be attached to R2 from its origin. The arrangement of the C fiber consists of two conspicuous dense lamellae that seem to be separated by a thinner lamella in between, like a sandwich. This is what I have tried to represent in my illustration.

The sections dude

I will now pause to discuss the left side of the main illustration: the "Section Details." You will have noticed that in the diagram of the flagellar apparatus, there are 4 lines that refer to the 4 cross-sections indicated in these "Section Details." I will begin by discussing Section 1: "B1 transversal section," where I have attempted to represent a cross-section of B1 and its associated structures according to what I have explained previously: B1 has a 9+0 arrangement (9 peripheral microtubular triplets). On the ventral side is the B fiber (the ventral side in this image would be approximately the lower half of B1). Towards the right (which in this image would be the upper left corner) are R1 along with the I fiber, the A fiber, and the S fiber, which connects to SA on the dorsal side of B1. The dorsal side of B1 in this image would encompass roughly the upper half of B1. The left side would be the lower right corner, where R2 and the C fiber are located.

Returning to the flagellar apparatus, the posterior flagellum (F1) has a particular feature: it possesses a flagellar vane (FVA), located on the dorsal side of F1 and appearing after the origin of the 9+2 axoneme of F1. It's true that in my illustration, the ventral side is, in the image, the orientation towards the left, and the FVA appears to be facing that direction, but the intention is to give the appearance that it's actually "behind the axoneme, on the dorsal side," which would be almost the opposite of the ventral side, which is what we're seeing "from the front" in the drawing. There's also the line for Section 2: "F1 transversal section," where it's clearer: the FVA is in the upper half of F1 (which is the dorsal area), and the lower half of F1 is the ventral side. The truth is, I've made some kind of mistake in representing it there, but honestly, I'm getting sleepy.

Finally, the last tedious thing with which I hope to finish writing this entry: you will notice that in the diagram of the flagellar apparatus, the "tip," or rather, the "beginning" or "anterior end" of the ventral groove (GR) is represented. Lara et al. (2006) suggest that it consists of these parts: a right margin (the edge) (RM), the right wall (RW), the floor of the GR (FL), the left wall (LW), and the left margin (LM). The GR is a groove; understand these parts as if we were talking about a tube cut in half longitudinally, or a semicylindrical water channel, such that the edges where this tube has been cut would be the left and right margins; the non-central curved parts on the sides, the left and right walls; and finally, the curved part that acts as the "base," "center," or "floor" of this cut tube, would be the "ventral groove floor."

These designations are important for what Lara et al. (2006) explain later: the arrangement of the structures adjacent to basal body 1 (B1) changes slightly at the beginning of the ventral groove. R1 divides into two parts: the outer portion (R1o) and the inner portion (R1i). Fiber I, which I mentioned earlier runs alongside the ventral side of R1, once it reaches the beginning of the ventral groove, runs only alongside R1o, presumably also on its ventral side, and they form an R1o/I complex, such that they are assumed to be together.

Fiber B, which is initially located on the right ventral side of B1, somewhat close to R1, once the ventral groove begins, continues only near the R1o/I complex and eventually connects to them.

Fiber A, which is originally on the dorsal side of R1, terminates shortly after the ventral groove begins.

R2, which is initially a compact bundle of 7 microtubules, begins to splay as the ventral groove begins. This also coincides with the termination of the C fiber, shortly after the start of the ventral groove.

The structures that continue alongside the ventral groove provide support for the parts of the ventral groove mentioned earlier. Thus, the B fiber supports the right margin (RM), the R1o/I complex supports the right wall (RW), R1i supports the floor of the ventral groove (FL), and to its left, the singlet (S). This suggests that the S fiber supports the left side of FL, and R1i the right side. The left wall (LW) and the left margin (LM) are supported by the microtubules of R2. This support arrangement can be seen more clearly in Section 4: "Ventral Groove: transverse section (not so proximal part)."

The sections but without labels

The "initial" or "predecessor" states of these structures during the initial (but maximum) stage of the ventral groove are shown in Section 3: "Ventral groove: Proximal start transversal section." The parts of the ventral groove I mentioned earlier are shown, along with how the structures are arranged before reorganizing as described in Section 4. Thus, in Section 3, R1 still exists as a complete structure (without an external or internal part), and the A fiber is still present near R1. Note that the microtubules of R2 are very close together, whereas in Section 4 they are more separated, as Lara et al. (2006) indicate occurs when R2 has already passed the beginning of the ventral groove.

Damn, my fingers and eyes have really hurt having to write all this. It's a mixture of satisfaction at having finished writing and being able to finally release the images on Wikimedia, but also of the hard work of having to thoroughly read about these structures to represent them correctly. 

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I guess it's part of the hobby.

Cryptomonas borealis Skuja 1956

This is an organism I've wanted to illustrate for a while because it seemed interesting compared to other Cryptomonas species, with the "borealis" part and all that. I don't really have much energy to write this post, but I'll try anyway. Then, to feel less guilty, I'll see if I can get around to writing something for the final project. I should notify my supervisor for another mandatory review next week. What follows is a notice regarding the use of the images and taxonomic context, which is almost entirely copied and pasted from the other Cryptomonas guides, so don't expect much ingenuity there.

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 borealis is another distant relative of plant ancestors.

bleeeeeh (˶˃ ᵕ ˂˶)

The following illustrations depict Cryptomonas borealis Skuja 1956, as the name is recorded on AlgaeBase. I have shown it in ventral view. The images are free to use and are also available on Wikimedia Commons. Of course, commercial use of these images is not permitted, nor is their use without proper attribution. "DOTkamina (2026)" is sufficient.

For the creation of these illustrations, as well as the text describing them, I have relied on and consulted the following works:

• "Chapter 18 - Cryptomonads". Brec L. Clay, 2015. Freshwater Algae of North America (Second Edition). Academic Press.
• "Cryptomonas borealis Skuja 1956". E.A. Molinari Novoa in Guiry, M.D. & Guiry, G.M. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. 2024.
• "Cryptomonas borealis Skuja, 1956". Martin Kreutz. Real Micro Life. 2021.
• "Light microscopical observations of the sigmoid species of the genus Cryptomonas Ehrenberg (Cryptophyceae) and their eventual pyrenoids". Pavel Javornický. Acta Musei Silesiae Scientiae Naturales. 63(1):1-24. DOI: 10.2478/cszma-2014-0001. 2014.
• "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.

Cryptomonas borealis is a rare species of Cryptomonas. 

Actually, it's not rare in any particular way; I just said that because the name sounded legendary. "B o r e a l i s"—few things surpass that in epicness. The C. borealis cell is oval with a wavy surface. In fact, I would describe it more accurately, in lateral view, as a kind of rectangular oval that has been bruised. It measures 20 to 50 µm in length.

The organism has two chloroplasts ranging in color from brownish to olive green. One would assume that both chloroplasts are the same color in each individual. In the ventral view, however, I have depicted each chloroplast as a different color: the "ventral" one more greenish and the "dorsal" one more brownish. But I'm sure that doesn't happen in real life. I made that decision to make it easier to distinguish both chloroplasts in the ventral view, but it doesn't mean they are bicolored in real life.

There are no pyrenoids; what exist are several hexagonal or oval starch granules. In the illustrations, I distinguish between "chloroplast 1 starch grains" and "chloroplast 2 starch grains," but this is purely for didactic purposes and to facilitate the separation of the two chloroplasts in the drawing. In reality, the starch granules of both chloroplasts should not differ in size, quantity, or color.

Furthermore, according to Clay (2015), I have represented two nucleomorphs as they are assumed to exist in Cryptomonas (one for each chloroplast, if there are two chloroplasts). Of course, their shape and location are almost speculative. Clay (2015) mentions that they are "between the pyrenoid and the nucleus," but I have represented them as being above the nucleus, since there are no pyrenoids in this species.

One notable feature of this species is the "gullet mouth," which is "widely open." This can be understood as the anterior part of the cell, where the vestibulum and gullet are located, being especially wide. It doesn't end in a "point" or a "curve" as occurs in other Cryptomonas species. In fact, from a lateral view, it literally resembles two jaws or "protrusions" surrounding the entrance (vestibulum), like "a fish with its mouth open," according to Kreutz (2021). I believe I've managed to represent this in my illustration, but you can check Kreutz (2021), Figure 1b, to get a better visualization. Furthermore, this arrangement results in one side of the cell around the vestibulum appearing more "prominent" than the other. In this case, the more prominent side is the dorsal side; you'll see that it's higher on that side than on the ventral side. This prominent area is known as the "apical rostrum."

The gullet, btw, reaches up to half the length of the cell and is covered with ejectisomes, as is common in other Cryptomonas species. In the illustrations of the organism in Kreutz (2021) and Javornický (2014), it appears that the ejectisomes do not completely cover the gullet; rather, there is a portion closer to the exterior ("the vestibulum") that is not covered by them. And that is how I have represented it.

The vestibulum has a "vestibular ligule," a characteristic of campylomorphic Cryptomonas species, such as C. borealis. However, this structure is almost speculative because it has not been reported for this specific species; rather, it is a characteristic that is "assumed" for campylomorphic Cryptomonas. You can learn more about this morphology in the entry on Cryptomonas obovata.

According to Hoef-Emden and Melkonian (2003), the furrow is curved, and I would venture to say that it extends to just under half the length of the cell, based on what I can observe in Hoef-Emden and Melkonian (2003): Figures 2 and 10. That is my main excuse for having depicted the large furrow.

Two Maupas bodies are represented, although the species can have as few as one, or even as many as three. The contractile vacuole is located anteriorly, beneath the apical rostrum. There is also a nucleus with a nucleolus located posteriorly, "in posterior third" (Kreutz 2021). I assume the nucleolus exists because, according to Clay (2015), in cryptomonads during interphase (the "normal" phase of cell life where it is not dividing, but simply existing), the nucleolus is "prominent and persistent."

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.

I assume that the flagellar arrangement in C. borealis is type 4, as described in Kugrens et al. (1987): this means: 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".

Kugrens et al. (1987)'s work does not mention that C. borealis has type 4 flagella. I infer this because its morphological relationship with C. curvata and C. platyuris, among other species, has been discussed (Javornický 2014 and Hoef-Emden and Melkonian 2003). And C. curvata and C. platyuris have type-4 flagella. Furthermore, flagellar type 4 in Kugrens et al. (1987) is associated with species described as campylomorphic by Clay (2015)... and C. borealis is campylomorphic and only has this morph according to Hoef-Emden and Melkonian (2003). All of this leads me to believe that C. borealis has this flagellar arrangement. But of course, this is speculative, and electron microscopy studies would be necessary to confirm it.

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 really think that was all I had to say about this species. I've had it ready for a long time—I mean, the illustrations—but I was too lazy to write it. Thankfully, I'm finally out of writer's block.

Pygsuia biforma Brown et al. 2013

Another one of the strange organisms I've been illustrating. I find the name funny because no matter how I look at it, it sounds like "pig." The name "biforma" is because it has two forms, indeed (obviously lol). Unlike Subulatomonas, which I was too lazy to illustrate, I actually illustrated both forms of P. biforma. I had it all ready when I realized a structure was missing and I had to redo it—what a pain!

Reminder (da f___ng reminder) that the images of the organism are free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

If you've ever stumbled across this obscure site, you'll know I'm a ₗₐzy bᵤₘ, so I'll take advantage of the fact that this organism is also a breviate (like Subulatomonas tetraspora), and copy the exact same taxonomic description, varying it for Pygsuia biforma. I hope you can forgive me. Or well, never mind, I already did it before with cryptomonad algae. So, idc.

Pygsuia biforma is not in AlgaeBase, which surprised me. It is in NCBI Taxonomy. The organism belongs to the family Pygsuidae, order Breviatida, class Breviatea. The truth is, I've only found the name "Pygsuidae" on Wikipedia. NCBI Taxonomy directly includes P. biforma as part of Breviatea.

The class Breviatea, the breviate amoebas, are strange amoebas that lack mitochondria (instead, they have structures similar to them, as you'll see later), have two flagella, and a metabolic style adapted to low oxygen (anaerobic). They are unusual because their taxonomic placement is uncertain.

The class Breviatea is included in the clade Obazoa, a group of eukaryotes that also includes Apusomonadida (amoebas that do have mitochondria, although some have modifications that resemble those of Breviatea) (Torruella et al. 2018) and Opisthokonta (amoeboid eukaryotes that share the characteristic of moving with the aid of a single posterior flagellum. In contrast, Breviatea and Apusomonadida move with at least one anterior flagellum. Opisthokonta is notable for encompassing organisms related to the ancestors of animals and fungi, as well as the animals and fungi themselves).

Obazoa is grouped with Amoebozoa (the "common amoebas" as such) in the clade Amorphea or Unikonta (common characteristic: a single flagellum) (Spiegel 2016). Amorphea is included in the clade Podiata (which would include Amorphea and CRuMs). Podiata is finally included in the large domain Eukaryota, related to other clades I've already covered and others I hope to discuss later, such as Metamonada (Giardia lamblia) or Diaphoretickes (which includes Archaeplastida (plants and relatives of plant ancestors), Pancryptista (which includes cryptomonad algae), the SAR group, and so on)...

I have relied mainly on two articles for the creation of the illustrations of this organism, as well as for writing its description:

• "Phylogenomics demonstrates that breviate flagellates are related to opisthokonts and apusomonads". Matthew William Brown, Susan Sharpe, Jeffrey D. Silberman, Aaron A. Heiss, B. Franz Lang, Alastair Simpson, Andrew J. Roger. Proceedings of The Royal Society B. 280(1769):20131755. DOI: 10.1098/rspb.2013.1755. 2013.
• "A SUF Fe-S Cluster Biogenesis System in the Mitochondrion-Related Organelles of the Anaerobic Protist Pygsuia". Courtney W. Stairs, Laura Eme, Matthew W. Brown, Cornelis Mutsaers, Edward Susko, Graham Dellaire, Darren M. Soanes, Mark van der Giezen, Andrew J. Roger. Current Biology. Vol. 4, Issue 11. 1176-1186 pp. 2014.

Well, this organism is certainly interesting. Uhm... I'm sure it won't seem so interesting to me once I explore its taxonomic relatives further. I've represented its two main forms: adherent and swimming.

In both forms, we can see that the organism has a nucleus (I assume it also has a nucleolus, but Brown et al. 2013 don't mention this organelle, so I've decided not to represent it); an elongated, double-membrane mitochondrial-related organelle (MRO) (usually only one) without obvious cristae, one end of which is close to the basal bodies; bacteria ingested in food vacuoles (I've represented two "morphs"—the more oval vacuoles are inspired by Brown et al. 2013, and the comma-shaped ones are based on the micrographs by Stairs et al. 2014); and starch-like granules (bodies), which Brown et al. (2013) mentions that there are "several," although only one is indicated and observed in the micrograph Figure 1 of that article... but I have depicted more. 

Of course, we mustn't forget the basal bodies (the structures that attach to the flagellar microtubules), which are at an obtuse angle. There is also a Golgi apparatus near the anterior end of the MRO. I have depicted it almost elongated, as can be seen in Brown et al. (2013): Figure 1e. Oh, and I almost forgot: there's also a "dorsal microtubular fan" (MDF), which surrounds the back of the anterior basal body and appears to continue close to the MRO (see Brown et al. 2013: Figure 1e). I could have sworn the MDF was visible in the image, but looking at it again, I've drawn it very thin... which is close to reality, but it's still not very noticeable at first glance. I apologize for any potential eye strain.

I almost forgot this too: the endoplasmic reticulum is speculatively shaped, and I assume it exists because it's a nearly ubiquitous structure in all eukaryotic cells. The rough endoplasmic reticulum has ribosomes (those light-colored, stuck-together dots in the image), but I assume ribosomes are also dispersed throughout the rest of the cell. The smooth endoplasmic reticulum doesn't have nearly as many ribosomes. In this illustration, as well as in all the previous ones of other organisms, I've always depicted the smooth endoplasmic reticulum as having shorter and somewhat wider bodies than the rough endoplasmic reticulum, but that's just my convention to try and make the difference more noticeable. In real life, both forms can be intertwined, have the same width, and not be noticeable as two completely separate structures. I think I should have included that caveat for the others as well.

That said, let's get to the morphs. The cell in its adherent form is pear-shaped. Dimensions: 8.5–18.5 mm long and 5–8 mm wide. It has two flagella. The anterior or apical flagellum is the longer one, 8 to 30 µm. The posterior flagellum is (usually) shorter, measuring less than the cell itself. It's inserted subapically and closely associated with the cell surface, hence why I've drawn it attached to the cell, in the region where the MRO would be underneath. Anatomically It's very likely that the spatial arrangement I've chosen for the illustration won't always be the case. 

When the cell is actively gliding in an adherent state, it develops prominent, filose pseudopodia, which form at the anterior end of the cell. For a moment, I was freaking out because in Brown et al. 2013: Figure 1a, more pseudopodia are shown not only at the anterior end but also along one side of the cell, extending to the posterior end. But apparently, pseudopodia can form at the posterior end and on the rest of the cell (Brown et al. 2013: Supplementary Data Figure S6 B). The only difference is that the posterior pseudopodia are more prominent and appear to be branched. I haven't represented that property because I just found out about it. And honestly, I don't think I'm going to make a new image representing that possible state. Sorry!

Finally, the other state is the swimming cell form. Here, the cell has a more rounded or elongated shape (not obviously pear-shaped; I depicted it as a somewhat narrow oval, but not quite pear-shaped). Cells in this form are 8.5–13 mm long and 3.7–5.3 mm wide. The anterior or apical flagellum is "long", 8.5–28 mm long, and inserted apically. The main difference lies in the posterior flagellum. In the adherent form, this was short and attached to the cell surface, but in the swimming form, the posterior flagellum is 50% longer than the anterior flagellum (16–37 mm long), and, although still directed posteriorly, it is more "free," meaning it is not as tightly attached to the cell surface.

That's really all there is to say about this organism. 

ヾ(^ ^ゞ

I hope this information and the images are helpful. Don't forget to give credit, and read the original articles where I got all this information if you want more technical details and so on. 

I'm signing off now 'cause I want to upload this to Wikimedia Commons quickly.

(∩♡°ω°)⊃

Porphyridium purpureum (Bory) K.M.Drew & R.Ross 1965

Well, it's an honor to begin the third set of illustrations with the 21st organism to be illustrated, and that honor goes to this single-celled red alga. Given how well-known it is and all the research surrounding it, I'm surprised it hasn't yet had an image representing it in its article. So, I saw the opportunity and took it.

Reminder that it is free to use under CC BY-SA 4.0, non-commercial, attribution required (DOTkamina 2026).

◝(๑꒪່౪̮꒪່๑)◜

Well, this is a single-celled red alga from the family Porphyridiaceae, order Porphyridiales, class Porphyridiophyceae, subphylum Proteorhodophytina. Within this subphylum, it shares characteristics with other groups of red algae, both filamentous and pseudofilamentous, which definitely appear larger due to their more multicellular organization. 

Finally, it belongs to the phylum Rhodophyta, which includes all red algae, and these are further classified within the infrakingdom Rhodaria (red algae and their relatives, which are basically Rhodophyta along with Picozoa and Rhodelphidia—guess what?—the first protists I illustrated!), subkingdom Biliphyta (which would encompass Rhodaria and Glaucophyta). 

Anyway, this subkingdom Biliphyta is considered obsolete according to Wikipedia, but AlgaeBase still uses it. The important point is that Rhodaria, along with Glaucophyta and Viridiplantae (plants and relatives of plant ancestors), these three clades, make up the large clade Archaeplastida. Archaeplastida, together with Pancryptista (class Endohelea and phylum Cryptista, which includes the cryptomonad algae I have illustrated several times previously), make up the large CAM clade.

The sources I used and read for the creation of the image, as well as the text where I explain it, are these:

• "A genetic and ultrastructural study of three clones of Porphyridium purpureum (Bory de Saint-Vincent, 1797) Drew et Ross, 1965 (Rhodophyta) from the marine microalgae collection of the Zhirmunsky institute of marine biology". K. V. Efimova, M. A. Kreshchenovskaya, N. A. Aizdaicher, T. Yu. Orlova. Russian Journal of Marine Biology. Vol. 40, No. 5, 364–374 pp. 2014.
• "Advances in the production of bioactive substances from marine unicellular microalgae Porphyridium spp.". Shaohua Li, Liang Ji, Qianwen Shi, Haizhen Wu, Jianhua Fan. Bioresource Technology. Volume 292. 2019.
• "Biological and technical aspects on valorization of red microalgae genera Porphyridium". Asep Bayu, Diah Radini Noerdjito, Siti Irma Rahmawati, Masteria Yunovilsa Putra & Surachai Karnjanakom. Biomass Conversion and Biorefinery. Volume 13, pages 12395–12411. 2023.
• "Enhanced growth and metabolite production from a novel strain of Porphyridium sp". Latifa Tounsi, Hajer Ben Hlima, Hana Derbel, David Duchez, Christine Gardarin, Pascal Dubessay, Marwa Drira, Imen Fendri, Philippe Michaud, Slim Abdelkafi. Bioengineered. Volume 15, Issue 1. doi: 10.1080/21655979.2023.2294160. 2023.
• "Granules associated with the chloroplast lamellae of Porphyridium cruentum". E. Gantt, S. Conti. Journal of Cell Biology. DOI:10.1083/JCB.29.3.423. 1966.
• "Porphyridium purpureum (Bory) Drew et Ross (Porphyridiales, Rhodophyceae)—first record of a marine unicellular red alga in New Zealand". W. A. Nelson & K. G. Ryan. Journal of the Royal Society of New Zealand. 1988.
• "Porphyridium purpureum microalga physiological and ultrastructural changes under copper intoxication". Zhanna V. Markina, Tatyana Yu. Orlova, Yuri A. Vasyanovich, Alexander I. Vardavas, Polychronis D. Stivaktakis, Constantine I. Vardavas, Manolis N. Kokkinakis, Ramin Rezaee, Eren Ozcagli, Kirill S. Golokhvast. Toxicology Reports, volume 8, 988-993 pp. 2021.
• "The Ultrastructure of Porphyridium cruentum". E Gantt, S F Conti. J Cell Biol. Volume 26, Issue 2. 365–381 pp. doi: 10.1083/jcb.26.2.365. 1965.
• "Unusual mitosis in the red alga Porphyridium purpureum". R. Bronchart and V. Demoulin. Nature 268, 80-81 pp. 1977.

Seen this way, it seems like an impressive bibliography, but most of it was mainly to learn for the first time about the anatomy of the organism, as well as aspects of its life, or other general topics. Anyway, here's the illustration:

Well, what can I say about this organism? The most striking feature is its stellate chloroplast, meaning it has a shape close to a star, although to me it looks more like an egg smashed on the floor. In the illustration, I've depicted the chloroplast with a series of curves inside, and these curves represent the thylakoids. In the center of the chloroplast is a pyrenoid of a darker tone. I don't know if the pyrenoid is actually darker than the chloroplast; in the micrographs I've seen, I haven't observed much difference in tone. What I do know is that the pyrenoid has some internal "curves" (which I've drawn) that aren't as compact as the curves (thylakoids) of the chloroplast. I have no idea what those thylakoid curves are (see images in Efimova et al. 2014; Gantt and Conti 1965; Gantt and Conti 1966; Markina et al. 2021; Nelson and Ryan 1988).

Other important organelles: the nucleus, of course, which has a nucleolus... or at least that's what I infer from what I see in the micrographs by Markina et al. 2021. Of course, in that article, the micrographs correspond to P. purpureum stressed by the presence of copper. But in another micrograph of Porphyridium cruentum, a distinctive area of ​​the nucleus is evident, which I assume is the nucleolus (see Gantt and Conti 1966). So I've depicted the nucleus with a nucleolus.

The other organelles tend to be located at the cell's periphery, not in the center (Efimova et al. 2014). Both starch grains and lipid bodies are present, and the latter are darker (according to Efimova et al. 2014). Starch grains are also included as peripheral structures, but I've depicted them more dispersed, in homage to the micrograph by Gantt and Conti (1966). It's important to understand that in my illustration, these starch grains are "in the periphery above the cell's center," not literally in the center.

The Golgi apparatus is also located at the periphery, according to Efimova et al. (2014), and I've depicted it as such, made of dictyosomes (the sacs) with attached vesicles. I've also depicted the mitochondria. According to Efimova et al. 2014, there are several tubular mitochondria. This feels strange to me because in most of my previous illustrations, I was getting used to the "single reticulated mitochondrion" scheme. It's a bit of a shock that this isn't the case in P. purpureum. These mitochondria are also distributed in the periphery. I've depicted the mitochondrial cristae as if they were tubular, but for that, I based my work on P. cruentum (see Gantt and Conti 1965). 

For the endoplasmic reticulum (or as Gantt and Conti 1965 call it, "endoplasmic reticulum"), I also relied on their description of P. cruentum: "neither extensive nor elaborate." That's why you'll see that I've depicted it peripherally (which actually means it's in contact with the cell surface and also with the nucleus, of course), and very simply, with relatively short "branches." I assume they must be similar across species.

Finally, the cell is enveloped in an "extracellular polysaccharide sheath," which is, indeed, just that: a thick mucilage covering made of pectins. In actual micrographs, you can identify this structure as a kind of transparent "aura" or "areola" visible around the cell.

RN it's so midnight, 3AM and I'm still in front of da computer lol. Playing Roblox before btw.

I think there's nothing more to say about this organism. I hope my computer doesn't crash so I can upload the images, because it's already night ೭੧(❛〜❛✿)੭೨

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.