Sinacroneuria bicornuata, Stark & Sivec, 2008

Stark, Bill P. & Sivec, Ignac, 2008, Studies On Sinacroneuria Yang & Yang (Plecoptera: Perlidae) With Description Of New Species From China And Vietnam, Illiesia 4 (15), pp. 150-153 : 152-153

Sinacroneuria bicornuata sp. n.

( Figs. 5-6 )

Material examined. Holotype ♂ (pinned) from China, Szechuan [Sichuan] Province, Mt. Omei [Emei Shan], July 1936, D.C. Graham ( USNM).

Adult habitus. Triocellate. General color pattern pale brown but details obscured due to specimen condition. Ocellar triangle covered with dark pigment but most of head apparently pale brown. Wings pale, veins yellow brown. Femora yellow brown, tibiae slightly darker.

Male. Forewing length 21 mm. Tergum 9 produced along posterior margin into a small lobe projecting over base of tergum 10; lobe densely armed with prominent sensilla basiconica. Tergum 10 with sensilla basiconica patches separated by posterior incursion of U-shaped membranous area ( Fig. 5 ). Paraproct tips small, acute and darkly sclerotized. Hammer present on sternum 9. Aedeagus armed with massive Y-shaped sclerite with long projecting horns and short stem; lateral aspect of apical aedeagal section with narrow supporting sclerites. Basal section of aedeagus membranous but armed with a band of brown, setal spines across ventrobasal area ( Fig. 6 ).

Female. Unknown.

Larva. Unknown.

Etymology. The species name is based on the prominent aedeagal horns.

Diagnosis. This species appears to be distinct from others on the basis of the large horn-like aedeagal sclerite with short Y-stem, the basal, aedeagal, setal spine patch, and the small, projecting mesal lobe on tergum 9. The holotype specimen bears a determination label of “ Acroneuria yiui (Wu) ” by Nathan Banks, but that species lacks the lobe on tergum 9 ( Wu 1935; Yang & Yang 1998), and the aedeagus lacks the Y-shaped sclerite of this species ( Yang & Yang 1998). The type specimen was previously studied by the senior author in 1974 and at that time, the aedeagus was fully everted and drawn but a decision was made to wait for fresh material before publication. Now, more than 34 years later, we proceed in order to continue the documentation of the diverse and interesting Asian stonefly fauna.

Figures

Figs. 5-6. Sinacroneuria bicornuata. 5. Male terminalia, 6. Aedeagus, ventral aspect.