𝘔𝘰𝘢𝘳 Protocryptomonas species: Protocryptomonas ellipsoidea Skvortsov 1969 and "Protocryptomonas obovatus Skvortsov 1960"

I wasn't planning on writing a post for two taxa, but the goal is to do it quickly. It's really a "filler" genus I chose to reach my sub-goal of 30 illustrations. And I plan to do the same for other genera in the Cryptomonadaceae family.

Both species belong to the genus Protocryptomonas. If you want more context about the genus (where I explain some of the taxonomic uncertainties surrounding it) and the type species (P. mukdenensis), then visit the page dedicated to P. mukdenensis.

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

Taxonomically, Protocryptomonas is a genus that, along with others (including Cryptomonas, of course), 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 Protocryptomonas is another distant relative of plant ancestors.

The references I used to write this post and also to create these illustrations are the following:

• "Algae Novae et Minus Cognitae Chinae Boreali-Orientalis 2. Flagellatae Prope Oppidum Mukden in Anno 1957 Collectarum". B. V. Skvortzov. 1960. Bulletin of Botanical Research. 1-8 pp.
• "On new genera of Cryptomonadinae recorded from North-Eastern China". B. V. Skvortzov. 1968. Journal of Japanese Botany. 8-16 pp.
• "Protocryptomonas ellipsoidea Skvortsov 1969". AlgaeBase. 2023. Formerly: E.A. Molinari Novoa in Guiry, M.D. & Guiry, G.M. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.

Let's get quick: here I present two species, Protocryptomonas ellipsoidea and Protocryptomonas obovatus.

The first entry in this post: P. ellipsoidea appeared in the 1968 article by good old Skvortsov. It is also recognized in AlgaeBase as Protocryptomonas ellipsoidea Skvortsov 1969. In that article, he mentions, and emphasizes, that the difference between P. ellipsoidea and the other two species also described there (P. obovata and P. chilomonoides) is its ellipsoidal shape. To me, that seems a rather vague distinction.

I think it's more noteworthy to highlight that P. ellipsoidea has two flagella, where the primary flagellum is twice the length of the cell, and the secondary flagellum is 1.5 times the length of the cell (in P. mukdenensis, the secondary flagellum was almost the same length as the cell). The cell's dimensions, by the way, are 11 to 18 microns long and 7 microns wide. It is also mentioned that the cell moves rapidly and in a rotational fashion.

The central nucleus, of course, I also omits the nucleolus. The contractile vacuole near de flagellar bodies.

The reticulated mitochondrion, Golgi apparatus, endoplasmic reticulum, and hypothetical vestibulum are represented. These structures should exist in cryptomonad algae species, but there is no direct evidence for this species (nor for the genus Protocryptomonas), so their shapes and sizes are speculative.

In Skvortsov's (1968) article, the description of P. ellipsoidea makes no mention of starch granules, so I based my representation on the general description of the genus Protocryptomonas (5 to 10 starch granules) and also used Figures 7 to 9 from that article, where the specimens have 3 to 7 starch granules of highly variable size, with some being larger than others and others roughly the same size. I have used Figure 9 as a base in combination with Figure 8, to represent, in my case, 6 starch granules, where one is very large and the rest are more medium-sized.

P. ellipsoidea was found in autumn in a cold-water pond near the city of Harbin. Its distribution is inferred to be in northern Manchuria, China.

Okay, now let's talk about the other species, "Protocryptomonas obovatus Skvortsov 1960." I've put it in quotation marks because it doesn't actually have a formally accepted taxonomic name. It's not even accepted in AlgaeBase. It appears alongside the description of P. mukdenensis in Skvortsov 1960.

Before continuing, I must clarify that the name "P. obovatus" is not the same as the other name "P. obovata" mentioned in Skvortsov 1968; that appears to be a different species with different characteristics. You will see this in a future post.

... So P. obovatus It's 12 to 13 microns long and 8 microns wide. The flagellar dimensions are similar to P. mukdenensis: the primary flagellum is twice the length of the cell, and the secondary flagellum is almost the same length as the cell. It has a central nucleus and a contractile vacuole near the flagellar bodies. The vestibulum, endoplasmic reticulum, mitochondrion, and Golgi apparatus are hypothetical in this illustration.

The major difference is that P. obovatus has "numerous starch granules scattered in the anterior part" of the cell. No exact number is mentioned; in Figure 19 of Skvortsov 1960, I would swear there are 20 to 21, and in the posterior region of the cell there are smaller dots that I honestly don't know what they are, but they can't be starch granules because the original description itself says they are "in the anterior region," not the posterior. I haven't represented those mysterious dots. But I have represented the starch granules; I would swear there are about 20.

P. obovatus was found in a lake near Mukden (present-day Shenyang), and its distribution is inferred to be in Northeast China, Liaoning Province. The same applies to P. mukdenensis.

And well, that's all for this post. It took me a while to write it because I was playing some "The Floor is Lava" games on Roblox. Remembering things, I guess, although I don't know what I'm supposed to remember there.

¯\_(⊙︿⊙)_/¯

Protocryptomonas mukdenensis Skvortsov ex C.E.M.Bicudo 1989

This post was originally going to be dedicated to another Cryptomonas species, specifically Cryptomonas marssonii, but I'm having some trouble representing the chloroplast (I think I'm going to have to rearrange layers or something, i'm about to get polymerized at this point with this shit).

So I started reviewing the taxonomy that includes the Cryptomonas genus and found that there are a ton of species and genera, some of them quite obscure. What if I tried to represent them?

And so begins the context for this genus, Protocryptomonas. It's considered a "rare" genus, but only because it lacks detail. No preserved specimens exist; all that remains are the illustrations and descriptions made by Skvortsov. Therefore, the genus is questionable, as to whether they are truly cryptomonads. The question, it seems to me, also lies in whether it's a true genus, or a form of a better-known species, but since only illustrations remain, not much can be determined. It amuses me that, despite everything, the genus and species were accepted taxonomically based solely on the images. You can read more about this in Bicudo (1989).

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

Taxonomically, Protocryptomonas is a genus that, along with others (including Cryptomonas, of course), belongs to the family Cryptomonadaceae. I don't have much more to add there, so what follows is a copy-paste of other descriptions of Cryptomonas species:  family Cryptomonadaceae is included in 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 Protocryptomonas is another distant relative of plant ancestors.

I should mention that my references for the text and images are:

• "A Companion to the Identification of Cryptomonad Flagellates (Cryptophyceae = Cryptomonadea)". Gianfranco Novarino. 2003. Hydrobiologia 502(1):225-270. DOI: 10.1023/B:HYDR.0000004284.12535.25
• "Algae Novae et Minus Cognitae Chinae Boreali-Orientalis 2. Flagellatae Prope Oppidum Mukden in Anno 1957 Collectarum". B. V. Skvortzov. 1960. Bulletin of Botanical Research. 1-8 pp.
• "Protocryptomonas Skvortsov ex C.E.M.Bicudo, 1989". AlgaeBase (formerly "E.A. Molinari Novoa in Guiry, M.D. & Guiry, G.M"). 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.
• "Validation of the generic name Protocryptomonas (Cryptophyceae: Cryptomonadaceae)". Carlos E. de M. Bicudo. 1989. TAXON. Vol. 38, Issue 1. 82-83 pp. https://doi.org/10.2307/1220898

Well then, to begin discussing this species, let's start with some general information about the genus. I have based myself on the most current description which is the one in AlgaeBase 2023, and it continues like this: "Free-swimming, biflagellate, dorsiventrally asymmetric monads; with a firm, smooth, hyaline periplast; elliptic or obovate with rounded ends; non-metabolic; flagella unequal, subapically inserted, one twice the cell length, the other one and one-half times the cell length; chloroplasts absent; with five to ten spherical starch grains; a single contractile vacuole near the flagellar bases; A little known freshwater genus recorded only from cold water ponds, impure ditch water and standing water near Harbin, northern Manchuria, China".

Some of these general characteristics are those I have represented for M. mukdenensis Skvortsov ex C.E.M.Bicudo 1989, which is the type species for Protocryptomonas. The central nucleus is visible (I have decided not to depict a nucleolus, as I don't know if one exists or should exist), as is the contractile vacuole near the "flagellar bases" (this leads me to believe it's near the basal bodies, which anchor the flagella to the cytoplasm, but I haven't depicted them). Bicudo (1989) mentions that there are "two contractile vacuoles," although the original descriptions by Skvortzov (1960) only mention one, and AlgaeBase also mentions one, so I'll conclude that there is only one contractile vacuole.

However, in Skvortzov (1960), the descriptions are in Latin and Chinese XDDD. But roughly translated by machine (thanks a lot, Google Translate!), it says the following about Protocryptomonas mukdenensis: oblong or ovate cell shape, 13 to 15 µm long, 7 to 9 µm wide.

Two flagella at the anterior end, the primary one twice as long as the cell, and the secondary one almost the same length as the cell. That's how I've represented them, with the secondary flagellum as if it were "ventral" to the primary one. This arrangement isn't mentioned anywhere; it's an inference derived from how I've been representing the flagella in the Cryptomonas illustrations (the ventral flagellum is shorter, and the dorsal one is longer).

So that's where the analogy comes in. According to Clay (2015), the vestibulum exists in all cryptomonads, and that would also include Protocryptomonas, but there's no actual data or evidence for that, so the vestibulum is highly speculative, which is why it's marked with a question mark and the text is transparent. The same applies to the reticulated mitochondrion, the endoplasmic reticulum, and the Golgi apparatus. These structures should be present in most eukaryotes, but I'm not sure if they exist in Protocryptomonas, given the shapes and sizes I've used to represent them. That's why they're speculative and presented in transparent text. If anything is more relevant, I'd say the reticulated mitochondrion, as Clay (2015) suggests that cryptomonads have this form. However, it's still entirely speculative for Protocryptomonas because there's no direct ultrastructural evidence.

In the general description for Protocryptomonas, AlgaeBase (2023) mentions 5 to 10 spherical starch grains (the organism lacks chloroplasts, and in my opinion, any other type of plastid). But for P. mukdenensis specifically, Skvortzov (1960) mentions that "Cellula oblonga vel ovata; granula amylaceae magna singula," or in Chinese if you prefer: "細胞長橢圓形或卵形；澱粉粒大，單一," which apparently means that the cells have large, individual starch granules. I assume that each cell has a single starch granule, which, according to the same article, is half the size of the cell and has the same width as the cell.

... So it's a huge thing, and it can't mean that each cell has "a few individual granules" because the cell would be too swollen and would have to be larger. Either that, or I simply don't know Latin or Chinese, which is true. So if you're reading this and think I'm misinterpreting everything, let me know in the comments here or on the Wikimedia discussion! Or something like that; sooner or later I'll see it and might correct it.

So, the conclusion is that I've represented P. mukdenensis with only one large starch granule. Since the image is designed as if viewed ventrally, the nucleus is dorsal and the starch grain is "ventral," as if it were covering the nucleus. Actually, this is just an assumption; I'm not saying it necessarily applies to all of them. It's something I inherited from how I've represented Cryptomonas species, with the chloroplasts "covering" the nucleus, which is "behind," although what actually happens is that the chloroplasts "envelop" the nucleus like a sandwich. Protocryptomonas doesn't have chloroplasts—uhm, did I already mention it doesn't have chloroplasts?

Idk what I'm doing with my life

And well, I suppose that's all I had to explain about this organism. It lacks other structures present in Cryptomonas or other genera. It does not have ejectisomes or a furrow/gullet system. More details providing context for Protocryptomonas are supposed to be found in this reference: Castro, A. A. J. d., C. E. d. M. Bicudo & D. d. C. Bicudo, 1991. Cryptogamos do Parque Estadual das Fontes do Ipiranga, SaoPaulo, SP. Algas, 2: Cryptophyceae. Hoehnea 18: 87–106. But unfortunately, I have not been able to access that reference.

What do you do in these situations? 

Well. Open Roblox. 

And listen to liminal music.