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Alex C.

Michigan Hatch Charts Wrong?

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Why do Michigan hatch charts have the dark hendrickson coming off starting in mid/late April and then the regular hendrickson coming off in mid May? They've got their scientific names right, subvaria in April, then rotunda in late mid/late May, but they have subvaria as the dark hendrickson, and rotunda as the light hendrickson.

 

Isn't subvaria the light hendrickson, and rotunda the dark?

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OLB-

 

The Ephemerella subvaria female dun is called a Dark Hendrickson, and the male dun is called a Red Quill.

The Ephemerella invaria (formerly E. rotunda) duns of both species are called a Light Hendrickson.

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thanks Taxon, I thought that invaria and rotunda were seperate species? One(can't remember which) being a little smaller than the other?

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thanks Taxon, I thought that invaria and rotunda were seperate species? One(can't remember which) being a little smaller than the other?

 

OLB-

 

You are right. Ephemerella invaria and E. rotunda were considered different species at the time some of the classic flyfishing entomology books were written. However, as taxonomists continue to learn more, taxonomic classification changes are inevitable. This results in splitting what was considered a single species into more than one, combining what were considered separate species into a single species, assigning a species to a different genus, creating a new genus, creating a new families from what were considered subfamiles, and endless variations on this theme.

 

The fact is, there can be consistent physical differences between insects of what are considered to be a single species, even in a given location, and can sometimes be readily noticeable, particularly in the larval (nymphal) life stage. Several examples come readily to mind. One would be the various middle tail configurations of the (old) species that were combined into Baetis tricaudatus. Another is the various horn configurations of the (old) species that were combined into Drunella lata.

 

Keeping up with taxonomic classification changes for aquatic insects can be quite a challenge. It’s my hope that my website provides the flyfisher (who is interested) with help in doing so.

 

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I see, who decides that species should be seperated or merged?

OLB-

 

Based on extensive reasearch, systematists (or taxonomists) propose taxonomic classification changes, probably to peer-group review organizations. I don’t know any details of how that works, nor who participates in the process.

 

However, I believe that Dr. W. P. McCafferty, Department of Entomology, Purdue University (and Mayfly Central), has been one of the leading systematists for N. American mayfly species, and that hundreds of others are engaged in this field of research.

 

EDIT

 

To illustrate my point, here is a list of those credited with species names for N. American Mayflies the past five years:

 

Jacobus & McCafferty

Randolph & McCafferty

Wiersema, Nelson, Kuehnl

McCafferty & Lenat

Sun, Webb & McCafferty

Waltz

Burian

McCafferty & Davis

Nieto & Dominguez

Randolph & McCafferty

Randolph & McCafferty

Wiersema, McCafferty & Baumgardner

Alba-Tercedor & McCafferty

McCafferty

McCafferty

Randolph & McCafferty

Wiersema & Baumgardner

Wiersema & Burian

Wiersema & Long

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Didn't the 2 species used to be grouped into one a long time ago? then they seperated them? ANd now remerged them? :blink:

 

OLB-

 

If you're referring to Ephemerella subvaria and E. invaria, the answer would be no. However, if you're referring to Ephemerella invaria and E. rotunda, the answer would be a qualified yes, and this is the reason:

 

Originally, Walker identified a species (in 1853), which was thought to be in genus Baetis, and named it invaria.

 

Fifty eight years later (in 1911), Morgan identified a species, which was thought to be in genus Ephemerella, and named it rotunda.

 

Fairly recently, probably since 1985, someone, likely McCafferty (and/or some of his colleagues at Mayfly Central) sorted this all out, and concluded that what Walker named Baetis invaria, and what Morgan named Ephemerella rotunda, were the same species.

 

It was further concluded that: the species Banks (in 1914) named Chitonophora vernalis and Ephemerella vernalis; the species Needham (in 1924) named Ephemerella feminina (misspelled femenina) and Ephemerella fratercula; the species Traver (in 1932) named Ephemerella inconstans; the species Brenner (in 1946) named Ephemerella choctawhatchee; the species Allen & Edmonds (in 1965) named Ephemerella simila; the species McCafferty (in 1985) named Ephemerella floripara were all the same species, that it should be called invaria because it was first identified by Walker, and it belonged in genus Ephemerella, therefore should be listed as Ephemerella invaria (Walker), 1853.

 

 

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Good Day,

 

Hehehehe... some one once told me it would be like separating blondes and brunettes into separate species. There is the physical difference, but the DNA stucture is the same.

 

Steelie

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