Kentomonas sorsogonicus Votypka et Lukes 2014

A strangely named organism, one of those I like to choose for the morbid fascination of illustrating the unknown. Kentomonas sorsogonicus isn't in AlgaeBase, so I based its taxonomy on that of NCBI Taxonomy.

The organism belongs to the subfamily Strigomonadinae, family Trypanosomatidae, order Trypanosomatida. That alone is enough to tell you that Kentomonas is related to the legendary Trypanosoma (sleeping sickness) and Leishmania. In this order, no one is spared: all its members are parasites. Trypanosomatids have several characteristics, among which I can highlight the kinetoplast (an organelle with a dense granule of kDNA located within the mitochondria, and usually associated with the basal bodies of the flagella), and the presence of glycosomes, which store glycolytic enzymes for glycolysis (Michels et al. 2006).

The order Trypanosomatida is included in the subclass Metakinetoplastina, along with the other orders Eubodonida, Neobodonida, and Parabodonida. These other orders are very diverse in their organisms, a few being parasitic and most free-living. In fact, I illustrated a species of Neobodonida, Klosteria bodomorphis, some time ago.

The subclass Metakinetoplastina is included in the class Kinetoplastea, and this in the phylum Euglenozoa, which makes Kentomonas distantly related to more "innocent" organisms like Euglena or Diplonema. Euglenozoa is included in the clade Discoba (which includes the other phyla Heterolobosea, Jakobea (which includes the last species I illustrated, Andalucia godoyi), and Tsukubea), and finally in the domain Eukaryota.

Anyway, the main source that I have used to create the illustrations, and the information written here, was "Kentomonas gen. n., a New Genus of Endosymbiont-containing Trypanosomatids of Strigomonadinae subfam. n." (2014), by Jan Votýpka, Alexei Yu Kostygov, Natalya Kraeva, Anastasiia Grybchuk-Ieremenko, Martina Tesařová, Danyil Grybchuk, Julius Lukeš and Vyacheslav Yurchenko. Protist, Vol. 165, Issue 6. 825-838 pp.

Another source was: "Farming, slaving and enslavement: histories of endosymbioses during kinetoplastid evolution", (2018), by Jane Harmer, Vyacheslav Yurchenko, Anna Nenarokova, Julius Lukeš and Michael L. Gingerby. Parasitology, 145, 1311–1323. https://doi.org/10.1017/S0031182018000781 

A peaceful screamer reminder: the following illustrations 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.

Kentomonas sorsogonicus was found infecting the hindgut of a female Sarcophaga fly (species undetermined), which was captured near Donsol, Sorsogon, in the Philippines. Its cellular form is called a "choanomastigote": an oval or rounded shape with a ring-like structure at its anterior end from which the flagellum protrudes. I have indicated this ring in the illustration. In Kentomonas sorsogonicus, the choanomastigote is more elongated, giving it a "barleycorn" appearance. You, as a likely native English speaker, will know what a "barleycorn" is because either I'm searching incorrectly, or I'm getting seeds I've never seen before.

Another unsettling thing is that the "choanomastigote" has the kinetoplast anterior to the nucleus (watch this image). I thought I'd messed up because I depicted the kinetoplast posterior to the nucleus in my illustration, near the basal body. However, in K. sorsogonicus, the kinetoplast doesn't appear to be fixed; its position varies depending on the individual, being posterior, anterior, or lateral to the nucleus, or wherever you like. But that's perfect for me because I didn't have to correct anything, haha.

Speaking of the flagellar pocket, it seems to be incredibly long and occupy a large part of the cell, as can be seen in Votýpka et al. (2014): Figure 2B, reaching the area where the nucleus and the endosymbiont are located (in the posterior region). Logically, "beneath" the flagellar pocket (which, remember, is an invagination that envelops the flagellar axoneme) is the basal body, whose size I don't know, so I've represented it with a "normal" size for me, but it's up to you to judge.

Flagellar axoneme

The axoneme is 9+2, the standard microtubular structure of eukaryotic flagella (9 peripheral microtubular doublets surrounding two central microtubular singlets). This axoneme, when enveloped by the plasma membrane, is what is called the "flagellum." Since the flagellar pocket is an invagination, its interior is technically lined by the plasma membrane. The flagellum, therefore, originates from inside the cell, emerges through the ring, and widens as it does so. The flagellum has a paraflagellar rod, a protein structure that supports the flagellum. In other trypanosomatids, this rod is well-developed, but in K. sorsogonicus and other species of the subfamily Strigomonadinae, it is inconspicuous (rudimentary or almost nonexistent). I have depicted the paraflagellar rod along a section of the first part of the flagellum as it emerges from the ring. I don't know if it will be a fragmented structure, if it's shorter, or if it occupies the entire flagellum.

The flagellar pocket is an invagination shaped like a round-bottomed bottle with a neck (like a Florence flask). This means that near the anterior part of the cell, where it opens with the ring, it's narrower, and the plasma membrane that acts as its inner "wall" is closer to the plasma membrane that surrounds the axoneme (that is, the flagellum). It's in this area of ​​contact that we find the desmosomes, two or three rows of them that attach the flagellum to the membrane of the flagellar pocket.

K. sorsogonicus, cell anatomy

Transversal section of the flagellar pocket in the anterior zone, with the desmosomes.

The organism has an oval-shaped nucleus, which, according to Votýpka et al. (2014): Figure 2B, appears to be located at the posterior of the cell, with the endosymbiont even further posterior. This endosymbiont is a β-proteobacterium, known as Candidatus Kinetoplastibacterium sorsogonicusi Yurchenko et Kostygov sp. n. This symbiont is typically surrounded by glycosomes, which is why I have depicted them in greater numbers around the symbiont.

The kinetoplast is cylindrical and has a loose network of kDNA fibrils. The kinetoplast is located within the mitochondrion, which, as in other species, is single and reticulated. In K. sorsogonicus, the mitochondrion is so reticulated that it extends close to the plasma membrane, pushing it outward like longitudinal horizontal varices, forming the longitudinal ridges visible on the cell's exterior. The mitochondria are rich in tubular cristae.

SEM external appearance.

The endoplasmic reticulum appears to be a structure as branched as the mitochondria, distributed throughout the cell, or at least that's what has been observed in other trypanosomatids (Sandes and Queiroz de Figueiredo 2022). In the case of K. sorsogonicus, its actual appearance is not described; I have depicted it as much less extended, almost near the nucleus. This shape and size are speculative, and it could actually be more widespread throughout the cell. The shape of the Golgi apparatus is also speculative.

In addition to the main image, I have also drawn the organism's external appearance as it would be seen under a scanning electron microscope (SEM), where the ring and, above all, the mitochondrial ridges are visible. I have also drawn the cross-section of the flagellum's axoneme with the paraflagellar rod; the cross-section of the anterior region of the cell where the flagellar pocket is narrow and in contact with the flagellum via desmosomes (in the main image, I have depicted two rows of desmosomes that are not very noticeable; in the cross-section, the desmosomes are more visible, but only one row is shown); and the cross-section of a posterior region of the cell, where the nucleus, the posteriorly widened portion of the flagellar pocket, the flagellum's axoneme within the flagellar pocket, and the mitochondrion are visible. In the cross-section, the mitochondrion appear as a cluster of individual, round mitochondria. I hope I have pointed out the branches near the surface that form the ridges, giving, in this cross-section, a wavy cell surface.

And now...

some non-labeled icons

That's all I had to say about this organism.

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°)⊃

Subulatomonas tetraspora L.Katz, J.Grant, L.W.Parfrey, A.Gant, C.O'Kelly, O.R.Anderson, R.E.Molestina & T.Nerad 2011

Aaaah, my mind feels foggy and my ribs are aching (not in the way you might imagine) because I just played Roblox's Hypershot game for about an hour, I think? But anyway, it's time to get back to doing something productive.

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

That said, I'll begin by providing the taxonomic context. Subulatomonas tetraspora is an unusual organism, in the sense that its position in the phylogeny was completely unfamiliar to me. In fact, on AlgaeBase it's listed as part of "Eukaryota unassigned," so it's playing coy. According to the English Wikipedia, the organism belongs to the family Breviatidae, order Breviatida, class 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)...

.............. And many more.

Fuck, I've barely scratched the surface of eukaryotic taxonomy.

ᕕ( ᐛ ) ᕗ

But anyway, back to Subulatomonas tetraspora. For the illustrations and the text here, I based them on a single article, which is where it is described in more detail: "Subulatomonas tetraspora nov. gen. nov. sp. is a Member of a Previously Unrecognized Major Clade of Eukaryotes", by Laura A. Katz, Jessica Grant, Laura Wegener Parfrey, Anastasia Gant, Charles J. O’Kelly, O. Roger Anderson, Robert E. Molestina and Thomas Nerad. Protist, Vol. 162, Issue 5. 762-773 pp. 2011. https://doi.org/10.1016/j.protis.2011.05.002

The organism has several morphologies (amoeboid, gliding, swimming, settling), but I was too lazy to illustrate them all, to be honest. I opted for the gliding form, and that's the form I've depicted in the illustrations.

The organism has characteristics typical of a standard eukaryotic cell: a nucleus with a central nucleolus, and a Golgi apparatus (which in this organism is described as "small" and without observable microtubules in its region). The dimensions of the entire cell (without flagella or pseudopodia) are usually 5 to 10 µm long and 3 to 5 µm wide.

As I mentioned, it belongs to the class Breviatea, organisms that lack true mitochondria. S. tetraspora has what the authors believe are possibly "hydrogenosomes." There are a few of them, and they have a double membrane. Hydrogenosomes likely evolved from mitochondria. The difference is that they lack cristae (which should mean that no texture is visible inside them, but in S. tetraspora a texture is observed, which I have represented as darker areas within the hydrogenosomes), and they function in an anaerobic environment, releasing hydrogen (H2) as a waste product. 

S. tetraspora is microaerophilic btw (meaning it is not completely anaerobic, but requires very little oxygen to thrive; amounts close to normal are poisonous to it).

Another peculiar feature is the food vacuoles, which contain the remains of bacteria in the process of digestion, which is what they eat (I have represented these digesting bacteria as very dark and irregular areas within the food vacuoles). The unsettling thing is that there are also bacteria within the cytoplasm, free-floating (in the illustration I have labeled this "Bacteria"). I suppose these must be ingested bacteria that have not yet been incorporated into a food vacuole.

The endoplasmic reticulum has a speculative shape, and I represent it as such because I assume it exists in all eukaryotes except for exceptions that should be noted. However, this is just an illustration, and it's worth noting that the endoplasmic reticulum could be less "branched," perhaps more extensive throughout the cell, with narrower sacs and tubules.

Finally, regarding external appearance: The cell is awl-shaped, with a "neck" approximately 6 µm long, which "extends along a substantial portion of the single flagellum and reappears when the flagellum moves to a new location." This leads me to believe that the neck acts as a "cover" for part of the flagellum, but I'm not certain. In the illustration, I've depicted the single flagellum emerging from the tip of the neck, but it assumes that it continues within the neck and is eventually connected to a basal body that appears to be located not at the tip of the neck, but rather near its base on the main cell body (see Katz et al. 2011, Figure 2D). The flagellum measures 6 to 12 µm in length. The flagellum is located anteriorly and is used for movement.

I have represented the basal body with a standard 9+0 microtubular arrangement (9 peripheral triplets and no central microtubules). This contrasts with the 9+2 arrangement of the flagellum, which has 9 peripheral doublets and two central microtubules; this arrangement is not shown. Technically, the illustration represents S. tetraspora in a "longitudinal" view (although it is not a cell section), and therefore the microtubules of the basal body and those of the flagellum should appear as closely packed hairs. 

However, I have chosen to represent the microtubular arrangement of the basal body in a cross-section to highlight the 9+0 arrangement. This assumes that the transition from 9+0 (basal body) to flagellum (9+2) does not occur literally at the tip of the neck, but at some intermediate point, I believe slightly closer to the cell body. Honestly, I'm not sure; the article doesn't mention anything about it either, which is why I haven't shown that connection.

Besides the flagellum, in the gliding form, which is the one I've shown, there are a series of small pseudopodia (cytoplasmic extensions) in the neck area, and another large pseudopodia at the rear. It seems that these pseudopodia don't exist in the swimming form; in the amoeboid form, they do exist, but they're distributed throughout the cell, very long, and the flagellum "disappears"—or rather, it seems to be reabsorbed. In the forms with the flagellum present, swimming or gliding, the neck also appears.

Man I'm tired

Anyway, I think that's all I had to say about this organism. The organism is most likely transparent and should appear grayish. You know what that means: the colors I've used in these illustrations serve more of an educational purpose and don't actually represent reality. That said, I hope you liked this information and found it useful. 

Goodbye.