Allocapnia PYGMAEA
Creators: name: Stark, Bill P.
name: Kondratieff, Boris C.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Plecoptera
Capniidae
Allocapnia

description: <i>ALLOCAPNIA PYGMAEA</i> GROUP Ross &amp; Ricker (1971) recognized six species (<i>A. aurora</i> Ricker 1952; <i>A. indianae</i> Ricker 1952; <i>A. nivicola</i> (Fitch 1847); <i>A. ohioensis</i> Ross &amp; Ricker 1964; <i>A. pygmaea</i> (Burmeister 1839); <i>A. smithi</i> Ross &amp; Ricker 1971) in the <i>A. pygmaea</i> group. There have been no subsequent changes to this species list. In this group the apical and basal segments of the male epiproct are usually subequal in length, and at least the distal half of the apical segment is armed with a patch of wave-like spikes. On the epiproct lower limb the notch delineating the apical spoon is absent or much reduced. Abdominal terga 7-8 typically bear dorsal processes, although the 7 th tergal process may be obscure or absent (e.g. <i>A. aurora, A. pygmaea</i>). The 8 th tergal process is notched and may bear a mesal tooth giving the process a trilobed appearance. Ross &amp; Ricker placed the <i>A. pygmaea</i> group as the sister group to the <i>A. rickeri</i> group. <i>Allocapnia pygmaea</i> is considered the most primitive member of the complex and <i>A. smithi</i> and <i>A. nivicola</i> are considered the most derived members of the group. The sister group hypotheses proposed by Ross &amp; Ricker (1971) for this group were based primarily on variations of the tergal processes, and we find no suitable characters on the epiproct to suggest modifications be made to these hypotheses. Males of four species in the group (<i>A. indianae, A. nivicola, A. ohioensis, A. smithi</i>) share trilobed processes on tergum 8 (Figs. 53, 59, 66, 77), whereas <i>A. aurora</i> and <i>A. pygmaea</i> share bilobed processes (Figs. 47-48, 71- 72). Two of the species, <i>A. indianae</i> and <i>A. ohioensis</i> also share trilobed processes on tergum 7; this latter condition is considered by Ross &amp; Ricker as the primitive one for tergum 7 structure “…because this [trilobed process] could have arisen as a single homeotic mutant…” and later become modified to a simpler arcuate structure in the ancestral form giving rise to <i>A. nivicola</i> (Fig. 58) and <i>A. smithi.</i>
description: Published as part of <i>Stark, Bill P. &amp; Kondratieff, Boris C., 2012, Epiproct And Dorsal Process Structure In The Allocapnia Forbesi Frison, A. Pygmaea (Burmeister), And A. Rickeri Frison Species Groups (Plecoptera: Capniidae), And Inclusion Of A. Minima (Newport) In A New Species Group, pp. 45-77 in Illiesia 8 (5)</i> on page 57, DOI: 10.5281/zenodo.4760725
description: {"references": ["Ross, H. H. &amp; W. E. Ricker. 1971. The classification, evolution, and dispersal of the winter stonefly genus Allocapnia. Illinois Biological Monographs 45: University of Illinois Press, Urbana, Illinois. 166 pp.", "Ricker, W. E. 1952. Systematic studies in Plecoptera. Indiana University Publications, Science Series No. 18. Indiana University Press, Bloomington, Indiana. 200 pp.", "Fitch, A. 1847. Winter insects of eastern New York. American Journal of Agriculture and Science, 5: 274 - 284.", "Ross, H. H. &amp; W. E. Ricker, 1964. New species of winter stoneflies, genus Allocapnia (Plecoptera, Capniidae). Transactions of the Illinois Academy of Science, 57: 88 - 93.", "Burmeister, H. C. C. 1839. Handbuch der Entomologie. Zweiter Band, Zweite Abtheilung, xii + 755 - 1050. Berlin: Theod. Chr. Friedr. Enslin."]}