Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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Identification: Key to Genera of Perlidae Nymphs, Couplet 1
Identification: Key to Genera of Perlidae Nymphs, Couplet 1
Adapted from Merritt R.W., Cummins, K.W., and Berg, M.B. (2019)
| Option 1 | Option 2 |
|---|---|
Occiput with a transverse row of regularly spaced spinules or distinctly elevated ridge 
| Occiput either without spinules, except possibly laterally near the eyes 
or else with a sinuate, irregularly spaced spinule row 
|
| Remaining genera: Agnetina, Claassenia, Neoperla, and Paragnetina | Remaining genera: Acroneuria, Anacroneuria, Attaneuria, Beloneuria, Calineuria, Doroneuria, Eccoptura, Hansonoperla, Hesperoperla, Perlesta, and Perlinella |
5 Example Specimens | 5 Example Specimens
This striking golden stonefly is the first of its species I've had the chance to photograph.
I'm not aware of any way to tell the two species of Doroneuria apart as nymphs, so this one is classified to species based on location alone. Doroneuria baumanni is found in the Cascades and in Washington, and the other species is not known here yet.
This is a difficult one. It keys convincingly to either Calineuria or Doroneuria. There is no mesal longitudinal row of silky hairs on thorax and abdominal dorsum, in either my pictures or anything I can see up close under the microscope. Lacking those hairs should indicate Calineuria. But abdominal sternum 7 has an incomplete posterior setal fringe, which would indicate Doroneuria, although the key says "usually" on that characteristic. For now I'm going with Calineuria, but it's far from certain. Maybe it's a younger Doroneuria and they don't grow that row of hairs until they're older. The markings on the head, especially the shape of the bright spot around the posterior ocelli, match online images of Calineuria californica better than Doroneuria.
|
| Go to Couplet 2 | Go to Couplet 5 |
Adapted from Merritt R.W., Cummins, K.W., and Berg, M.B. (2019)
The current couplet is highlighted with darker colors and a icon, and couplets leading to this point have a icon.
Couplet 1 (You are here)
Leads to Couplet 2:
- Occiput with a transverse row of regularly spaced spinules or distinctly elevated ridge
Couplet 2
Leads to Couplet 5:
- Occiput either without spinules, except possibly laterally near the eyes or else with a sinuate, irregularly spaced spinule row
Couplet 5
Leads to Claassenia
(Claassenia sabulosa):
(Claassenia sabulosa):
- Abdominal terga with more than 5 intercalary bristles
- Western North America
Leads to Couplet 4:
- Abdominal terga with no more than 4 intercalary bristles
- Eastern North America
Couplet 4
Leads to Agnetina:
- Posterior spinule fringe of abdominal sternum 7 complete
- Cerci without a long setal fringe
Leads to Paragnetina:
- Posterior spinule fringe of abdominal sternum 7 incomplete
- Cerci with at least a few long silky setae
Leads to Couplet 6:
- Occipital spinules in a sinuate, irregularly spaced row, more or less complete behind posterior ocelli
Couplet 6
Leads to Couplet 10:
- No distinct occipital spinule row or a few scattered spinules may be present near the postocular setal fringe (sf 16.106)
Couplet 10
Leads to Hesperoperla:
- Abdominal terga with
- Western North America
Leads to Couplet 7:
- Abdominal terga with >5 intercalary bristles
Couplet 7
Leads to Attaneuria:
- Pronotum laterally fringed with a complete, close-set row of long setae (sf 16.114)
- Posterior fringe of abdominal terga with numerous long setae whose length is 3/4 or more the length of abdominal segments
- Eastern North America Uncommon
Attaneuria
Leads to Couplet 8:
- Pronotum fringed laterally with short setae, not so closely set
- Posterior fringe of abdominal terga mostly of short setae whose length is about 1/4 the length of abdominal segments
Couplet 8
Leads to Perlesta:
- Cerci without a dorsal fringe of long silky setae
- Abdomen of most species speckled (dark pigment at bases of intercalary setae)
- Primarily Eastern North America
- common
Leads to Couplet 9:
- Cerci with prominent dorsal fringe of long, silky setae
- Abdominal terga not speckled
- Western North America
Couplet 9
Leads to Doroneuria:
- Dorsum of thorax and abdomen with a mesal, longitudinal row of long, fine, silky setae (best seen in lateral view)
- Abdominal sternum 7 usually with incomplete posterior fringe
Leads to Calineuria
(Calineuria californica):
(Calineuria californica):
- No mesal longitudinal row of silky hairs on thorax and abdominal dorsum
- Abdominal sternum 7 usually with a complete posterior fringe
Leads to Couplet 11:
- Postocular fringe reduced to 1-3 long setae (sf 16.107)
- Pronotal fringe of 2-3 setae at corners
- Eyes set forward on head
Couplet 11
Leads to Couplet 12:
- Postocular fringe with a close-set row of several thick spinules
- Pronotal fringe well developed, consisting of a close-set row of spinules or setae, occasionally incomplete laterally
Couplet 12
Leads to Perlinella:
- Femora and tibia with dorsal (outer) and ventral (inner) fringes of long silky setae
- Eastern North America
Perlinella
Leads to Hansonoperla:
- Femora and tibia with only dorsal (outer) fringe of lonk, silky setae
- Eastern North America
- Rare
Hansonoperla
Leads to Anacroneuria:
- Two ocelli
- Lateral pronotal fringe complete
- Arizona and Texas
Anacroneuria
Leads to Couplet 13:
- Three ocelli
- Lateral pronotal fringe incomplete
Couplet 13
Leads to Eccoptura
(Eccoptura xanthenes):
(Eccoptura xanthenes):
- Head with large area of yellow in front of median ocellus (sf 16.106)
- Eastern North America, Appalachian Mountains and foothills
Eccoptura
(Eccoptura xanthenes)
(Eccoptura xanthenes)
Leads to Couplet 14:
- Head mostly brown, usually with yellow M-shaped mark in front of median ocellus
Couplet 14
Leads to Acroneuria:
- Cerci with fringe of long, silky setae, sometimes reduced, but at least on basal segments (sf 16.119)
- Pronotal flange wider at posterior angles than along lateral margins
- Widespread
Leads to Beloneuria:
- Cerci without basal fringe of silky setae
- Pronotal flange narrow throughout
- Eastern North America, Southern Appalachians or Piedmont
Beloneuria
Start a Discussion of this Couplet
References
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.