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C. Riley Nelson
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taxon links [up-->]Arcynopterygini [down<--]Plecoptera Interpreting the tree
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This tree diagram shows the relationships between several groups of organisms.

The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

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Tree from Stark and Szczytko (1984).
Containing group: Plecoptera


Perlodidae is one of the largest families of Plecoptera with over 250 species divided between the nearctic, palearctic, and oriental regions. The nymphs are distinctive in often having contrasting patterns of light and dark coloration as well as having gills which are unbranched (or absent). They are predators in the streams where they occur.. They occur in the entire range or lotic environments, from small streams to large rivers.

There has been a tendency to split the genera of Perlodidae such that they contain few species. Monotypic genera abound. Contrast this with the very large genus Isoperla, which may well consist of over 200 species when all species have been described.


Synapomorphies for Peltoperlidae: 1, body stout, head prognathous, cockroach-like nymphal body form; 2, male cercal segments fused; 3, nymphal coxae with flap-like lobe.

Discussion of Phylogenetic Relationships

Different authors have divided up the family Perlodidae into various subfamilies and assigned the genera in a variety of ways. Stark & Szczytko (1984) sorted out these classifications and produced the one given above using characters of adults, nymphs, and eggs.


The Perlodidae have a high proportion of genera with one or few species. The classification in this list follows that of Stark & Szczytko (1984) and the numbers of species as shown by Zwick (1973) with a few additions, especially in Arcynopterygini (Stark & Szczytko 1988). There have been many additions since Zwick (1973) that have been missed. Please contact Riley Nelson so those additions can be made.



Nelson, C. H. 1996. Placement of Helopicus rickeri Stark in Hydroperla Frison (Plecoptera: Perlodidae) with the description of the adult female, nymph, and egg and a cladistic analysis of Hydroperla. Proc. Entomol. Soc. Washington 98: 237-244.

Stark, B. P. and S. W. Szczytko. Egg morphology and classification of Perlodinae (Plecoptera: Perlodidae). Ann. Limnol. 20: 99-104.

Zwick, P. 1973. Insecta: Plecoptera. Phylogenetisches System und Katalog. Das Tierreich 94. Walter de Gruyter and Co., Berlin. 465 pp.

Title Illustrations
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Scientific Name Hydroperla crosbyi, Diura knowltoni
Location Texas (Hydroperla crosbyi), Colorado (Diura knowltoni)
Specimen Condition Live Specimen
Copyright © 1996
About This Page

C. Riley Nelson
Brigham Young University, Provo, Utah, USA

All Rights Reserved.

Citing this page:

Nelson, C. Riley. 1996. Perlodidae. Version 01 January 1996 (under construction). http://tolweb.org/Perlodidae/13952/1996.01.01 in The Tree of Life Web Project, http://tolweb.org/

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Each ToL branch page provides a synopsis of the characteristics of a group of organisms representing a branch of the Tree of Life. The major distinction between a branch and a leaf of the Tree of Life is that each branch can be further subdivided into descendent branches, that is, subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

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