Trying to identify these little hypotrichs lures beginners like me into a taxonomical quagmire.
The rigid-bodied ones tend to be slightly easier. The fellow in your first picture has an angular Stylonychia-like shape, a sharply incised AZM with "lapels," and thick , dangly transverse cirri. It certainly looks like a Stylonychia, but I don't see the three caudal cirri that would confirm it. Perhaps they are there, but out of focus? If not, perhaps it is
Parastylonychia. But as long as we're considering other rigid-bodied hypotrichs, how can we know he is not Sterkiella (Histrio) or Histriculus? So we squint at the pictures and wonder: are the marginal cirri "confluent at the rear"? Are the frontventral cirri "linear"? How many macronuclei am I seeing?
Hmmm.
A little frustrated, we go on to the second creature, one of the dreaded small, flexible hypotrichs. This one is wonderfully clear. We have a very nice view of the midventral cirri, and the oral membranelles are raised in beautiful relief. Marginal and transverse cirri are nice and clear. It has a multi-noded macronucleus (four at least, possibly six)...that should rule out a few organisms! Maybe a Gastrostyla? That arrangement of midventral cirri suggests Keronopsis. Reading up about Keronopsis, you find yourself being sucked into the nomenclatural vortex of the Urostyloidea, where researchers (with access to silver-impregnation and electron microscopy!) are struggling to arrive at firm defiinitions of Holosticha, Anteholosticha, Paraholosticha, Kerona, Keronopsis, Psudokeronopsis...and slowly we begin to realize that, to identify this one little guy with confidence we need to know a heck of a lot more than we do! And it will take years to get there...
So we (and by "we" I mean "me," of course.
) heave a mighty sigh, say...gee, I dunno.
