Drunella grandis

Moved

Moved from Drunella.

… Tim Loh, 1 April, 2009 - 8:28pm

Second look

Upon more careful inspection, I'm noticing long dorsal abdominal spines (look toward the rear of abdomen), dorsal thoracic tubercles, and what appear to be hornlike tubercles on top of the head (look at left eye). These would seem to place this nymph in the grandis/spinifera group (of Drunella) rather than in the coloradensis/flavilinea group. (Cf. "grandis" image here for a clearer picture of the traits of that group. You can enlarge by clicking on that image.)

… Lloyd Gonzales, 30 March, 2009 - 1:11pm

New images

confirm your observations. Any way to choose between grandis and spinifera?

… Arlo Pelegrin, 1 April, 2009 - 4:42pm

Nice!

From what I understand, the tubercles on the head of spinifera are supposed to be pointed, and the last two pairs of abdominal spines are much (2X-4X) longer than the preceding ones. I would surmise that this is probably one of the grandis subspecies--D. g. grandis, D. g. ingens, or D. g. flavitincta.

… Lloyd Gonzales, 1 April, 2009 - 5:00pm

Check the abdominal spines

in the 4th picture in the series. The last 2 pairs are much longer than the preceding ones. Does this change your analysis?

… Arlo Pelegrin, 1 April, 2009 - 5:23pm

No...

I believe the last pairs of spines are longer than the preceding spines in all species/subspecies in this group. The others are just not as long as in spinifera.

… Lloyd Gonzales, 1 April, 2009 - 5:51pm

Moved

Moved from Spiny Crawler Mayflies.

… Arlo Pelegrin, 27 March, 2009 - 12:54am

Drunella, but not doddsii

D. doddsii has femora of more equal width and lacks the projection on the forefemur. It's difficult to know from the photo, but this might be coloradensis.

… Lloyd Gonzales, 26 March, 2009 - 3:24pm