Perlomyia excavata, Sivec & Stark, 2012

Sivec, Ignac & Stark, Bill P., 2012, The Genus Perlomyia Banks In Taiwan (Plecoptera: Leuctridae), Illiesia 8 (11), pp. 119-124 : 122

Perlomyia excavata sp. n.

( Figs. 5-8 )

Material examined. Holotype ♂, paratypes 4♂, Taiwan: Kaohsiung County, E Tientzu, 2400 m, 23°15’24’’N, 120°54’51’’E, 29 March1996, I. Sivec, B. Horvat, ( PMSL). Additional paratypes: Taiwan: Hualien County, Tzuen, Taroko National Park, 1890 m, 24°11’35’’N, 121°23’43’’E, 13 April 1996, I. Sivec, B. Horvat, 1♀ ( PMSL). Kaohsiung County, E Tientzu, 2450 m, 23°15’15’’N, 120°55’52’’E, 30 March 1996, I. Sivec, B. Horvat, 2♂, 2♀ ( PMSL); E Tientzu, 2450- 2500 m, 23°15’25’’N, 120°54’42’’E, 23 October 1996, I. Sivec, 4♂, 1♀ ( PMSL), 2♂, 1♀ ( BPS); Hsinan shan, 2200 m, 23°04’24’’N, 120°50’28’’E, 31 March 1996, I. Sivec, B. Horvat, 1♀ ( PMSL). Taichung County, Wulin, Sheipa National Park , 1820 m, 24°22’56’’N, 121°18’43’’E, 28 October1996, I. Sivec, 2♂, 2♀ ( PMSL). Taitung County, W Hsiangyang, 2580 m, 23°15’48’’N, 120°59’27’’E, 30 March 1996, I. Sivec, B. Horvat, 1♀ ( PMSL).

Adult habitus. General color dark brown to black, typical of genus.

Male. Forewing length 7 mm. Epiproct long, slender in dorsal aspect and hook shaped in lateral aspect ( Figs. 5, 7 ). Tergum 9 notched along posterior margin, forming a prominent U-shaped cleft which extends nearly to the anterior margin of the segment; posterolateral margins of notch produced into slender finger-shaped processes. Small knobs absent from tergum 10. Cerci bearing a prominent basal lobe with rounded distal margin visible in dorsal aspect, and a small subapical spine. Paraprocts fused into a broad, thick process bearing a slender, retractable, sclerotized rod ( Fig. 7 ). Apex of sternum 9 produced into a triangular, upwardly curved structure ( Figs. 6- 7 ). Vesicle longer than wide ( Fig. 6 ).

Female. Forewing length 8 mm. Sternum 7 produced into a rounded plate which overlaps the base of sternum 8 ( Fig. 8 ). Mesal, rectangular sclerites of sternum 8 narrowly divided by membrane; mesal sclerites extend slightly beyond base of sternum 9; lateral wing-like sclerites somewhat foot shaped and attached to anterolateral margins of mesal sclerites.

Larva. Undescribed.

Etymology. The species name refers to the U-shaped, excavated area of tergum 9 of the male.

Diagnosis. This is the only known Perlomyia species in which the male 9 th tergum exhibits a U-shaped cleft, similar to that found in males of the eastern Nearctic genus Zealeuctra ( Ricker & Ross 1969) . A similar structure also occurs on tergum 7 for Leuctra fusca (Linnaeus) ( Zhiltzova 2003a) . As noted above the female is similar to P. angulata among Taiwanese species, but is distinguished by the location of the attachment points between sclerites on sternum 8.

Figures

Figs. 5-8. Perlomyia excavata. 5. Male abdominal terga 7-10. 6. Male abdominal sterna 7-10. 7. Male abdominal segments 9-10, lateral aspect. 8. Female abdominal sterna 6-10.