Friday, January 11, 2013

"Lumpers" and "Splitters" and the breakup of the Limnephilidae (Northern case-maker) family

(The Limnephilid [Northern case-maker] Pycnopsyche gentilis.)

When I first got into this business and worked with the local group that monitors streams, the director told me that entomologists are a bunch of "lumpers" and "splitters."  Some take several genera, lump them together and give them a family name; others do just the reverse, they split up established families into separate groups.  Actually, the two actions go hand in hand: families are split into groups of genera, groups from which new families are then created.

We've seen a good example of "splitting" and "lumping" in the caddisfly work we've been doing this winter.  In 1977, the Limnephilidae family consisted of 52 genera: it was the largest family of the caddisfly groups.  The genera on which we've recently focussed a lot of attention -- Neophylax, Apatania, and Goera -- were 3 of those 52.  (See Glenn B. Wiggins, Larvae of the North American Caddisfly Genera (Trichoptera), 1977,  pp. 179 - 287.)    That's no longer true.  

1. Neophylax is now one of five genera in the newly created  Uenoidae family: four of those five genera were former Limnephilids -- Farula, Neothremma, Neophylax, and Oligophlebodes.

2. Apatania is now one of five genera in the newly created Apataniidae family: all five genera were former Limnephilids -- Allomyia, Apatania, Manophylax, Moselyana, and Pedomoecus.

3. Goera is now one of four genera in the newly created Goeridae family: all four genera were former Limnephilids -- Goera, Goeracea, Goerita, and Lepania.

And there's a fourth new caddisfly family made up of former Limnephilids -- Rossianidae -- which consists of Goereilla and Rossiana.  But those are genera we will not run into -- they are only found in the West.

The Limnephilidae family, now consisting of 39 genera, is still a very large group.  But, with entomologists, you never know if the "splitting" and "lumping" is over.  Up until now, the splitting and lumping has been done for morphological reasons.  But DNA is the new way to go, and who knows where that will lead?

1. Family Uenoidae, genus Neophylax: Neophylax consimilis

2. Family Apataniidae, genus Apatania: Apatania incerta

3. Family Goeridae, genus Goera: Goera fuscula (?)  (photos used with permission)

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