Bruce Taylor

I'm delighted by the idea of amoebae jetting around like squids. 😁 Sadly, it doesn't happen. Like other arcellinids (many of which also have spines on their shells) they crawl along the substrate with their pseudopods, which only protrude through the aperture and never through the "horns".

Nope, still haven't run into Legendrea! But I've mostly been poking around in submerged Scorpion-moss and Sphagnum.

I picked out as many as I could, in the time I had, and should have enough to sequence & measure. 😀 I kept the original jars, too, but after two days in the car I don't expect to see many more live ones.

Home again, now, with my boreal bog plunder!

Promethea = PROvora + MEteora + HEmimastigophora. The new supergroup, unifying previously “orphan” lineages with gene-rich mitogenomes. Position of #telonemids is still uncertain. #protistsonsky tinyurl.com/yk9xkt49

Last day in the field...time to wind down, pack up, put my stuff away. Of course, the sneaky shelled amoeba I've been chasing all week SUDDENLY decides to start blooming like crazy. #ProtistsOnSky #amoebae

In an unconscionable decision, the Smithsonian Institute has decided to no longer support the Biodiversity Heritage Library from 1 Jan 2026. Please someone step up and take it over.

Mine are for holding my glasses in place. So..secondary organs of sight, essentially. 😉

BHL contains the foundation of our understanding of biodiversity. 🌱 🌏 🦎 📖 🪱 🧪 🦉 There are countless researchers, educators, policy makers, fields, institutions, databases & species that rely on BHL. Please share our Call for Support as widely as you can: blog.biodiversitylibrary.org/2025/06/tran...

The quartz shards are embedded in some kind of organic cement, the exact makeup of which is not known (likely polysaccharides and proteins).

Oh, sorry. 😄 The shells are air-dried on carbon adhesive tabs mounted on SEM stubs, then sputtered with gold/palladium and put right in the machine.

Scanning electron microscope 🙂

Interestingly, organic cement in my populations of D. leidyi is similar to that of D. bacillariarum...but different from the cement of D. elegans shown in Todorov & Bankov. Meanwhile, D. bacillariarum has long been suspected of being identical to D. elegans. The taxonomy is "under construction". 😄

The Todorov & Bankov "atlas" is nice. It includes morphometric tables...very handy! D. leidyi was synonymized w/ D. elegans by Mazei & Warren in 2012. I'm skeptical, too, but shd add that consistently distinct phenotypes can be molecularly identical (see Hyalosphenia papilio paynei).

My copy of Leidy needs a new binding too. Customs agents slashed the spine with boxcutter while checking to see what kind of contraband I might be importing. The nearest modern equivalent to Cash, Wailes & Hopkinson, or Penard, is Ferry Siemensma's fabulous website!

Also...that's a really nice picture!

Yup, Difflugia leidyi...named for Joseph Leidy, who found a single specimen of the morphotype, which he didn't give a name. He was careful, that way, reluctant to create new taxa. :)

But why does an amoeba need horns on its shell? They're quite carefully made, with flat plates neatly glued around them (possibly scales from another organism). The spheres around the mouth are siliceous resting cysts of chrysophyte algae. #ProtistsonSky #MEvoSky #Amoebae #Peatlands

Exactly. I'm a curator on iNat, and have spent a LOT of time identifying eukaryotic microbes. I often write long explanations, with links to the literature. The idea that some bot could scrape and repackage my work is dismaying, even if it does a good job (which it probably won't).

iNat getting cozier with generative AI, not sure that's going to play well with everyone.

Ugh. When know-it-all "large language model" AI starts pontificating on things it has read about but can't actually see, the results can be ludicrous. See the attached chatGPT fail, from a reddit thread.

Oddly, the "warts" are hardened globules of organic cement, and the amoeba itself is not seen here. In this species, the globules of cement are laid down as thick rings, perforated with a single hole. In some testate amoeba species, the rings are thinner, with a kind of latticework inside.

Thanks, very interesting!

Anyone who has watched a hypotrich ciliate scooting around on its cirral legs, ducking for cover when startled, then stepping out to seize some fast-moving prey...has to at least THINK about cognition. ;) An old hypothesis, killed by electron microscopy: www.itcamefromthepond.com/2013/11/29/t...

Thanks! I came to protistology from poetry. So, some of these things are still somewhat new to me, as well. ;)

It's usually just referred to as "organic cement". I'm curious to know more about these fossil protists!

The glue is secreted in vesicles, generated in the Golgi apparatus and deposed as these discrete blobs...forming a matrix which varies in appearance from one species to the next. In some, the solidified matrix is quite fancy (see the attached pic of cement in Lesquereusia spiralis).

YouTube video by Bruce Taylor Cylindrifflugia bacillariarum (=Difflugia bacillariarum)

Yes, they're held in place by globules of organic cement (two of the pics show closeups). They seem to use whatever diatoms happen to be blooming, and will mix species readily. Not sure if C. bacillariarum preys on diatoms, but some arcellinids do. An old video: www.youtube.com/watch?v=W2t6...

Thanks, Andrew! It's a pretty amazing group of organisms.

Arcellinid amoebae that build "agglutinated" shells tend to like siliceous materials...especially quartz when it's available. Where minerals are scarce, they'll happily build with diatoms, chrysophyte cysts, etc. This species is particularly good at it! 😎