Ephemeroptera: Baetidae of Gunnison County, Colorado
Introduction to the Mayfly genus AcentrellaBengtsson, 1912
Minature Blue Winged Olive, Small Minnow Mayflies, Minute Graywinged Brown
Updated 27 Jan 2010
On this website:
Regarding the nymphs, both species lack a "thumb" on their labial palp which separates them from Baetis. They both have long setae on the backs of their legs as you can see in the photo below. A. insignificans has hind wing pads while A. turbida does not.
Bengtsson,S 1912 Neue Ephemeriden aus Schweden. Entomologisk Tidskrift 33:107-117.
Jacobus,LM and McCafferty,WP 2006 A new species of Acentrella Bengtsson (Ephemeroptera: Baetidae) from Great Smoky Mountains National Park, USA. Aquatic Insects 28:101-111. PDF
They describe a new species (Acentrella barbarae) and provide a key to the larvae of the seven North American Acentrella species.
Lugo-Ortiz,CR; McCafferty,WP 1998 A new North American genus of Baetidae (Ephemeroptera) and key to Baetis complex genera. Entomological News 109 5, 345-353. PDF
Waltz,RD 1994 Field recognition of adult Acentrella and Heterocloeon (Ephemeroptera: Baetidae). Great Lakes Entomologist 26(4):321-323.
The author shows that adult Acentrella and Heterocloeon have an anterior process on their mesothorax. This is distinctive for these two genera. Or in plain english, Acentrella adults have a bump on their back just in front of their wings, which is not present in any other local adult mayflies.
Waltz RD; McCafferty WP. 1987. Systematics of Pseudocloeon, Acentrella, Baetiella, and Liebebiella, new genus (Ephemeroptera: Baetidae). Journal of the New York Entomological Society 95:553-568.
Wang,TQ; McCafferty,wp 1996 New diagnostic characters for the mayfly family Baetidae (Ephemeroptera). Entomological News 107 2, 207-212. PDF
" The growing good of the world is partly dependent on unhistoric acts; and that things are not so ill with you and me as they might have been, is half owing to the number who lived faithfully a hidden life, and rest in unvisited tombs." -- George Eliot