Isoperla irregularis
Creators: name: Verdone, Chris J.
name: Kondratieff, Boris
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Perlodidae
Isoperla
Isoperla irregularis

description: The following couplets to the keys to males, females, and ova are taken directly from Szczytko &amp; Kondratieff (2015). New couplets are given to include the new species. <b>Males</b> 11 Dorsal head pattern pale, usually without dark brown bands or brown markings connecting ocelli (Figs. 14.1, 12.1) …………………….…… 12 11’Dorsal head pattern with dark brown bands connecting ocelli (Figs. 17.1, 20.1, 33.1) ……... 13 12 Vesicle 3X as long as wide, set in a deep U-shaped depression ¾ as long as length of vesicle (Fig. 14.2); paraprocts lightly sclerotized, bluntly pointed apically, not deflected ventraapically (Fig. 14.4), aedeagus with erect posteromesal sclerotized unicorn-shaped rod (Figs. 14.6, 14.7); head pattern occasionally with thin dark brown bands connecting ocelli distribution–widespread–eastern and midwestern North America ……………………………. <i>I. dicala</i> 12’Not as above …………………………………... 12a 12a Posteromedial sclerotized structure of the aedeagus composed of a thin sclerite bearing 10 short spines and setae (Figs. 6-8); paraprocts broadly triangular extending only slightly over the posterior margin of tergum 10 (Figs. 3, 7, 8) ………………………………………... <i>I. evanescens</i> 12a’ Posteromedial sclerotized structure lobe-like, deflected ventrally with scattered concentrations of stout sharp spinulae (figs. 12.6, 12.10, 2.11, Szczytko &amp; Kondratieff 2015); paraprocts lightly sclerotized, elongate, sharply pointed apically, extending over ca. ¼-½ length of tergum 10 (figs. 12.3,12.5, Szczytko &amp; Kondratieff 2015) …………………...….. <i>I. decepta</i> Females 1 Head without a dark pigment pattern, usually without dark brown bands or brown markings connecting ocelli (Figs. 12.1, 14.1) …………….. 2 1’ Dorsal head pattern with discernible dark brown bands connecting ocelli (Figs. 42.1, 6.1)... 3 2 Subgenital plate broadly triangular, extending ½ length of 9 th sternum; usually with posteromedian nipple (Fig. 14.5); distribution– widespread, eastern North America through midwestern US ……………………..……. <i>I. dicala</i> 2’ Subgenital plate evenly rounded to broadly triangular extending over &amp;frac13; or &amp;frac23; length of 9 th sternum (fig. 12.4, Szczytko &amp; Kondratieff 2015; Fig. 9) …………………………………………… 2a 2a Subgenital plate evenly rounded extending over &amp;frac13; length of 9 th sternum (fig. 12.4, Szczytko &amp; Kondratieff 2015) ………………………. <i>I. decepta</i> 2a’ Subgenital plate broadly triangular, extending over &amp;frac23; length of 9 th sternum (Fig. 9) ………………………………………... <i>I. evanescens</i> Eggs 1 Collar absent (Figs. 12.18, 22.13, 35.13) ……….. 2 1’ Collar present (Figs. 28.14, 36.9, 41.13, 58.15) …6 2 Chorion covered with raised reticulate thickened ridges, some not connected, eclosion line absent, inter-reticulate punctations absent (figs. 35.13, 35.14 Szczytko &amp; Kondratieff 2015)...... <i>I. nana</i> 2’ Not as above …………………………………… 2a 2a Inter-reticulate punctations present (Fig. 14) ………………………………………... <i>I. evanescens</i> 2a’Chorion without raised reticulate thickened ridges, eclosion line present or absent (figs. 12.18, 22.13, 22.14 Szczytko &amp; Kondratieff 2015) …………………………………………………….. 3 3 Cross section triangular, eclosion line wide, smooth (Figs. 22.13, 22.15) …...……. <i>I. irregularis</i> 3’ Cross section not triangular, either round or concave, eclosion line absent (Figs. 12.18, 23.21, 57.15) ……………………………………………... 4 <b>Biological Notes.</b> There is no information about the biology or life cycle of <i>I. evanescens</i>. Based on the above records, the emergence period appears to be from early May to mid-June and, as with most eastern <i>Isoperla</i>, a univoltine life cycle is presumed. The type locality, Wolf Creek (Fig. 20), has a diverse stonefly fauna. Other adult stoneflies collected with the new species at the type locality were <i>Acroneuria abnormis</i> (Newman, 1838), <i>A. kosztarabi</i> Kondratieff &amp; Kirchner, 1993, <i>Agnetina capitata</i> (Pictet, 1841), <i>A. flavescens</i> (Walsh, 1862), <i>Amphinemura delosa</i> (Ricker, 1952), <i>A. nigritta</i> (Provancher, 1876), <i>A. wui</i> (Claassen, 1936), <i>Diploperla morgani</i> Kondratieff &amp; Voshell, 1979, <i>I. dicala</i> Frison, 1942, <i>I. montana</i> (Banks, 1898), <i>I. signata</i> (Banks, 1902), <i>Leuctra alexanderi</i> Hanson, 1941, <i>L. duplicata</i> Claassen, 1923, <i>Neoperla occipitalis</i> (Pictet, 1841), <i>Paragnetina media</i> (Walker, 1852), <i>Perlesta decipiens</i> (Walsh, 1862), <i>P. puttmanni</i> Kondratieff &amp; Kirchner, 2003, and <i>P. teaysia</i> Kirchner and Kondratieff, 1997.
description: Published as part of <i>Verdone, Chris J. &amp; Kondratieff, Boris, 2016, A New Species Of Isoperla Banks (Plecoptera: Perlodidae) From The Appalachian Mountains, Virginia &amp; West Virginia, U. S. A., pp. 74-85 in Illiesia 12 (13)</i> on pages 83-85, DOI: 10.5281/zenodo.4752829
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