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3. Litobrancha recurvata

Collected a couple of these last week. Pretty cool mayfly if you ask me!

Great photos, Eric. Wow, what a hairy faced critter. I don't remember seeing an ephemerid before whose tusks were so completely covered.

BTW - I agree with your ID. It's quite ironic that the only things on this guy's face that aren't hairy (antennae) are significant characters that connote Litobrancha.:)

I really like all of the burrowers. Do you have any idea what the evolutionary benefit the single gill
on the first abdominal segment would be? I often wonder about that, just like the single gills on some of the Heptageniids.

Good question. I suppose a good place to start would be to find out the advantages of single vs. forked gills and vice versa. I believe that the plate-like ones of baetids and ephemerellids are more for ventilating the surface area of the body where oxygen can be adsorbed as opposed to actually functioning as pure respiratory organs. I think they also provide the vital function of salt absorption so important to freshwater creatures. If I remember right, assuming the oxygen is high enough with a little water movement, studies have shown that baetids can survive quite well with all their gills removed. The feathery forked gills of ephemerids on the other hand are purely respiratory organs, so maybe Litobrancha's preferred habitat meets their oxygen needs without the fully forked 1st gill. But it may be that like many vestigial animal characters, the answers still elude us. Finally, what the heck do I know? I'm in way over my head here, so take what I've said with a grain of salt. I have a tough enough time just trying to ID these buggers.:)

BTW - how did you collect it?

That seems reasonable to me, obviously the habitats seem to dictate gill structure to a large extent. But when you look at the gils of an Ephemerellid, Baetid, Heptageniid (any that are not fringed) they seem to be very much like a balloon. So do they function as a respiratory organ as well as a mechanical ventilation system? I seem to think that I may have known more about this at one time...I've got high mileage...





Collected by hand, I didn't have much time I was giving a demonstration to a group and had about 15 minutes to try and find some of the buggers. The stream had changed drastically since I was there last year due to flooding, and in areas where each handful of silt would give me a half dozen or so of these guys in the past, the substrate had changed and the habitat was not right. I did manage to find one place and got two and then I had to go. I may be able to get back, and I also know of at least two other streams with substantial populations.