Adorable apusomonads

Behold, purveyors of tiny soil flagellates: today, Santa brings you not one, but two whole species of Apusomonas. In fact, both described species of this, poor neglected genus. That's right, I've seen 'em all*, and after this post, you will too.

*I'm sure there's plenty more out there who've yet to encounter the microscope. Or be paid any attention to if seen. In fact, these may in fact be new species for all I know. They do fit their respective described ones quite nicely though, I think.

Apusomonas is a member of the Apusomonads, a group that includes Apusomonas, Amastigomonas, then Thecamonas, etc (as of Cavalier-Smith & Chao 2010 Protist) and, according to David Patterson (presumably) at Micro*scope, Etceterix etcetera (noticed by Opisthokont). Apusomonads seem to lean towards branching as sister to opisthokonts. They make their living by nibbling on bacteria, which they crawl over and ingest at their posterior ventral surface. Apusomonads are fascinating from both morphological and evolutionary perspectives, and perhaps if you prod Opisthokont persistently enough, he'll eventually dust off his blog and give these adorable creatures their deserved publicity.

For now, enjoy their strange and amusing mode of motility. By the way, the flagellar basal bodies are located at the kink in the proboscis, not within the cell body proper as in normal eukaryotes. Considering there's a strong tendency for the flagellar basal bodies to be fairly closely associated with nucleus among normal, non ass-tailed (opisthokont) eukaryotes, this is quite odd.

A.proboscidea Type species. First described in 1922.

A.australiensis
Differs from A.proboscidea in having a bit of a kink on the left side of its body. (it's crawling on the coverglass here, so it's upside down/ventral side up). Seems to have only been reported in Australia thus far. Now we know it lives in North America too (or some sort of new species, but I doubt it).

A.proboscidea (left) and A.australiensis (right) from their respective Micro*scope pages:

Want to find your own? Grab some soil, put in a dish and fill with some water. Let it stand for a couple of days, and the apusomonads should crawl out of their cysts. I placed coverslips on the surface, which tends to attract benthic-y crawly things. After about 3 days, the coverslips were transferred to the slide, and there was about one apusomonad per cover slip (n=2, heh). Careful though: they're pretty small – around 10µm. A.australiensis is slightly bigger, at least of my two specimens. Good luck!

Sunday Protist - Assorted oddballs

As I scramble to finish a chapter before my supervisor notices his hiring mistake, instead of writing out a mini-review paper about a single group of sorts, I'll use the opportunity to point out a few of the oddballs I've accumulated lately. Many of them have just a single paper, or a passing mention and a reference to a paper I can't get easily (and that would likely be in some language I can't read to begin with...), and thus they don't really make good weekly protists by themselves. But yet, many are too cool to ignore mentioning.

Our first exhibit is a peculiar association between a coccolithophorid haptophyte (small phytoplankton), Reticulofenestra sessilis, and a centric diatom, Thalassiosira sp.:

The thing in the centre is the centric diatom. The scaley things around are the coccoliths, or calcified scales, of the haptophytes Reticulofenestra clustering around it. The exact nature of this relationship is unknown, though presumably beneficial for the haptophyte, as R.sesslis is found almost exclusively attached to diatoms. Image by from nannotax.org; original citation - Gaarder & Hasle 1962 Nyü Mag Bot (which doesn't exist online *gasp*)

Speaking of haptophytes, here's another cool-looking one. There is quite a bit to say about haptophytes overall, just too lazy to do it right now. There is a post in the making though...

Umbellosphaera. The things on the surface are its coccoliths, of which each individual is intricately crafted into a chanterelle/trumped-like shape. SEM on the left from a nice image repository/course supplement by Isao Inouye from U Tsukuba, one of the Meccas of protistology. (Website is in Japanese, unfortunately for [most of?] us. I really need to learn Japanese someday...) Image of single coccolith on the right from eol.org.

Now for an obligatory ciliate. Trichodina is a cute little peritrich (group that includes the coiled-stemmed-trumpet Vorticella) that deserves more attention than just a pretty picture, but its looks can't wait to be exposed. Both the top and bottom sides have cilia, and the creature is like a miniature robotic vacuum cleaner, vacuuming the fish gills (or other substrates, like jellyfish) of bacteria and various other prey that accumulate there. In doing so, it causes fish disease, but the cute lil' thing didn't mean to!

Left: Trichodina 'vacuuming' fish gills (source). Middle: DIC image of the Trichodina 'sucker' (surprisingly from National Geographic, of all places). Right: Drawing of the ciliate. (HJ Clark 1866 Am J Sci) Will surely come back to it someday!

And last for today, this little critter is absolutely adorable. There's actually quite a bit to say about it, but I'm not gonna do it because some other blogger is far more qualified to write it up. Perhaps after the conference season calms down a little, said blogger could share their wonderful stories with us...

Apusomonas proboscidea. To paraphrase Opisthokont, 'cute Apusomonas' would be redundant. You see that little protrusion at the top? It wiggles 'spastically' as the critter crawls forward along its flagellum. If you're really keen check out the movies in this recent paper on apusomonads (TC-S alert!). Left: Karpov & Myl'nikov 1989 Zoologicheskiy Zhurnal (in Russ.) Right: Flemming Ekelund at ToLWeb (Apusomonas is really tiny...)

That's it for today. Am going out of town until middle of next week, will likely lack internet (eeek, how will I live?!), so if comments are mysteriously ignored, that's why.