Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This is a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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This topic is about the Mayfly Genus Caudatella
This Western genus is unimportant, but Caudatella heterocaudata and Caudatella hystrix are said to sometimes produce fishable hatches.Example specimens
Konchu on Oct 29, 2010October 29th, 2010, 1:36 pm EDT
The paper is in press now, so I can share an updated taxonomic synopsis of the "unimportant" genus Caudatella. Have fun.
Caudatella edmundsi (Allen, 1959)
Caudatella columbiella (McDunnough, 1935), comb. n.
= Ephemerella californica Allen and Edmunds, 1961, stat. n., syn. n.
Caudatella heterocaudata (McDunnough, 1929)
= Ephemerella circia Allen and Edmunds, 1961, stat. n., syn. n.
Caudatella hystrix (Traver, 1934)
= Ephemerella spinosa Mayo, 1952
= Ephemerella cascadia Allen and Edmunds, 1961
Caudatella jacobi (McDunnough, 1939)
= Ephemerella orestes Allen and Edmunds, 1961
Caudatella edmundsi (Allen, 1959)
Caudatella columbiella (McDunnough, 1935), comb. n.
= Ephemerella californica Allen and Edmunds, 1961, stat. n., syn. n.
Caudatella heterocaudata (McDunnough, 1929)
= Ephemerella circia Allen and Edmunds, 1961, stat. n., syn. n.
Caudatella hystrix (Traver, 1934)
= Ephemerella spinosa Mayo, 1952
= Ephemerella cascadia Allen and Edmunds, 1961
Caudatella jacobi (McDunnough, 1939)
= Ephemerella orestes Allen and Edmunds, 1961
Taxon on Oct 29, 2010October 29th, 2010, 3:18 pm EDT
Luke-
From your posting, it appears that what was previously Caudatella heterocaudata and its (3) subspecies are now Caudatella heterocaudata (with no subspecies), and (new species), Caudatella columbiella. Is that correct?
From your posting, it appears that what was previously Caudatella heterocaudata and its (3) subspecies are now Caudatella heterocaudata (with no subspecies), and (new species), Caudatella columbiella. Is that correct?
Konchu on Oct 30, 2010October 30th, 2010, 2:48 am EDT
columbiella was an old species that was synonymized with heterocaudata; i think it is a separate species
circia, californica and heterocaudata were all subspecies of heterocaudata
it turns out that californica is the same thing as columbiella
circia does not hold up as a nominal entity under most current philosophies. at the time it was described, the authors acknowledged that it probably interbred with other variants of heterocaudata, and the defining characters varied even in the population at the type locale. so, it should be considered the same species as heterocaudata
circia, californica and heterocaudata were all subspecies of heterocaudata
it turns out that californica is the same thing as columbiella
circia does not hold up as a nominal entity under most current philosophies. at the time it was described, the authors acknowledged that it probably interbred with other variants of heterocaudata, and the defining characters varied even in the population at the type locale. so, it should be considered the same species as heterocaudata
Taxon on Oct 30, 2010October 30th, 2010, 10:42 am EDT
Thanks, Luke.
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