Mesonemoura yulongana Li & Yang

Li, Weihai & Yang, Ding, 2009, A new species of the genus Mesonemoura (Plecoptera: Nemouridae) and a key to the males of species known from China, Zootaxa 2231, pp. 62-68 : 65-67

Mesonemoura yulongana Li & Yang , sp. nov.

( Figs. 1–7 )

Diagnosis. This species is characterized by the ninth tergum being produced into a mid-posterior, asymmetric protrusion fringed with 10 or more stout, black spines ( Fig. 1 ) and by the flagellum of the epiproct being long and curved, enlarging apically to form a tongue-like lobe flanked by a bifurcate apex ( Figs. 1, 2 , 6 ).

Male. Forewing length 5.7–5.9 mm (n=7), hindwing length 4.6–4.8 mm. Head, appendages, antennae shades of brown. Thorax dark brown; legs pale brown to brown except distal half of femora which are banded dark brown ( Fig. 3 ); wing membranes hyaline, veins brown. Abdomen including hypoproct brown; hairs on abdomen mostly pale. The body darker in older specimens.

Terminalia. Tergum nine weakly sclerotized, with a subtriangular median indentation at anterior margin and a semicircular mid-posterior protrusion fringed with 10 or more stout, black spines ( Figs. 1 & 5 ). Sternum nine with hypoproct wide and subquadrate basally, then distinctly tapering medially toward tubular tip, vesicle claviform and slightly swollen subapically ( Fig. 4 ). Tergum ten sclerotized except posterolateral margin being heavily sclerotized with a narrow median longitudinal slit originating from anterior margin of tergum ten which is extended in a concavity below epiproct ( Fig. 1 ). Cercus one-segmented, slightly sclerotized, longer than wide, with a darkly sclerotized apically mark in older specimens ( Figs. 1 & 4 ). Epiproct has strongly sclerotized lateral bands at base, bearing a long, curved flagellum which is broad at base, narrowed medially, and enlarged apically to form a tongue-like lobe flanked by a bifurcate apex ( Figs. 1, 2 , 5 & 6 ). Paraprocts bear a darkly sclerotized basal margin, divided into three lobes: outer lobe mostly sclerotized with a dark lateral band extended medially to a bulbous tip that exceeds the length of the median lobe; median lobe broad at base with a sclerotized quadrate area adjacent to inner lobe; inner lobe narrow, darkly sclerotized, about as Female. Unknown.

Nymph. Unknown.

Ecological notes. The species was collected from a single, minimally disturbed, cool-water stream that drained into Lanyue Lake. There adults were found on small stones at the water’s edge. This stream originates from a spring, fed by snow melt from Mt.Yulong. Flow of the stream was reduced to a trickle by long-term drought.

Type Material. Holotype: male ( HIST), China: Yunnan, Lijiang, Mt. Yulong, Baishui stream of Lanyuegu Valley, 2800 m, 27o21΄N, 100o10΄E, 2009. IV. 9, Weihai Li. Paratypes: 4 males ( HIST), same data as holotype; 2 males, same data but leg. Pengyan Xu ( CAU).

Distribution. China (Yunnan).

Etymology. The epithet refers to the type locality of the new species, Mt. Yulong.

Remarks. The new species is similar to M. sbordonii Fochetti and Sezzi from Yunnan in the general shape of the epiproct, but it may be separated from the latter by the presense of the enlarged tongue-shaped lobe on the epiproct and the by the asymmetric, spined posterior margin of tergum 9. The epiproct of M. sbordonii has a bifurcate tip but no apical lobe, while the posterior margin of tergum 9 is not produced medially and lacks dark spines ( Fochetti and Sezzi 2000).

Figures

FIGURES 1 – 3. Mesonemoura yulongana sp. nov. (male). 1. Terminalia, dorsal view. 2. Epiproct, lateral view. 3. Femur of hind leg, lateral view.

FIGURES 4 – 7. Mesonemoura yulongana sp. nov. (male). 4. Terminalia, ventral view. 5. Terminalia, lateral view. 6. Epiproct, dorsal view. 7. Right paraproct, caudal view.