Help with an ID, please

billporter1456 · Post by **billporter1456** » Thu Jul 24, 2014 4:26 am

I don't know if this little video is sufficient for anyone to ID this critter. I first thought it was Halteria, but I haven't seen Halteria retract or fold up cilia the way this guy did at 1'32" of the video.

https://www.youtube.com/watch?v=y9g-a0klkPE

Bruce Taylor · Post by **Bruce Taylor** » Thu Jul 24, 2014 5:13 am

Yes, Halteria, probably H. grandinella. These guys are fast.

http://www.ncbi.nlm.nih.gov/pubmed/15754357

billporter1456 · Post by **billporter1456** » Thu Jul 24, 2014 5:26 am

Bruce Taylor wrote:Yes, Halteria, probably H. grandinella. These guys are fast. http://www.ncbi.nlm.nih.gov/pubmed/15754357

Thanks, Bruce! You and Carlos (in his reply under the YouTube video) agree that its Halteria, and that's more than sufficient for me. Is the disappearance of the cilia at 1'32" of the video typical of the genus? Or of grandinella in particular? I've seen lots of Halteria in my samples but hadn't run across this particular variety.

microthings · Post by **microthings** » Thu Jul 24, 2014 6:35 am

wow, fast!! Can't help with ID's but i like the video!

Bruce Taylor · Post by **Bruce Taylor** » Thu Jul 24, 2014 7:00 am

billporter1456 wrote:Is the disappearance of the cilia at 1'32" of the video typical of the genus?

It could be that the cilia (oral polykinetids, in this case) are moving too fast to be recorded. When reversing direction, Halteria flap their membranelles about 230-290 times per second!

More fun facts from Ueyama et al.:

H. grandinella has a cell size of about 20 µm but the backward swimming speed reaches 2 mm/s. Therefore, the ratio of velocity to cell size is in the order of 100, much larger than for other organisms

billporter1456 · Post by **billporter1456** » Thu Jul 24, 2014 10:44 am

Bruce Taylor wrote: More fun facts from Ueyama et al.:

H. grandinella has a cell size of about 20 µm but the backward swimming speed reaches 2 mm/s. Therefore, the ratio of velocity to cell size is in the order of 100, much larger than for other organisms

So if I, at 6 feet tall, could move at a speed of 100 times my body length, I could move 600 feet per second. That's equivalent to over 400 miles per hour! (Unless my math is wrong, which happens with increasing frequency.) Clearly, Halteria moves faster, for its size, than any mammal. It seems ironic to me that Halteria's name begins with, "Halt!"