Neoperla mesostyla, Wang, Hong-Liang, Wang, Guo-Quan & Li, Wei-Hai, 2013

Wang, Hong-Liang, Wang, Guo-Quan & Li, Wei-Hai, 2013, Two new species in the subfamily Perlinae (Plecoptera, Perlidae) from China, ZooKeys 313, pp. 81-90 : 84-87

Neoperla mesostyla sp. n. Figs 4-5

Type material.

Holotype: male, China: Guangxi autonomous region, Mt. Jiuwanshan, Jiuren Station next to Rongjiang River, 950-1150 m, 25.0673N, 109.2563E, light trap, 3 Aug. 2003, Zhang Li-Li. Paratype: 1 male, same data as holotype.

Male.

Forewing length ca. 14.8 mm. General body color brown. Distance between ocelli nearly as wide as diameter of ocellus. Head slightly wider than pronotum, with a small triangular interocellar patch and another black triangular patch on frons (Fig. 4A); compound eyes dark; antennae dark brown. Pronotum pale brown with darker anterior and median stripes (Fig. 4A); wing membrane pale brown, veins dark; legs yellowish brown, distal fourth of femora, basal fifth of tibiae and tarsi darker (Fig. 4C).

Terminalia.

Process of tergum 7 forming a large subquadrate plateau, mostly covered with dense sensilla basiconica patches but with few sensilla basiconica at margins (Fig. 4B). Tergum 8 with an upcurved tongue-shaped process, with sparse ventral tiny spines. Tergum 9 without sensilla basiconica patches. Hemitergal lobes slender and curved laterally near midlength (Fig. 4B). Aedeagal tube plump (length 3 × width at basal bulb), ventrally with a mesal bifurcate lobe bearing a basal common stem, dorsal surface heavily sclerotized, the pigmentation slightly expanded mesolaterally, membranous sac 1.5 × as long as tube and gradually curved ventrad to form a loop; sharp to stout small spines occur along dorsal surface toward apex (Figs 4D, E, 5).

Zwick & Sivec defined the bulb side of the tube as being ventral, however, the sac of the new species forms a loop so that the spines of apical half of the dorsal surface are actually ventrally directed; we herein discuss dorsal or ventral surfaces of the sac as if it were straight, as such in Neoperla flagellata Li & Murányi ( Li et al. 2012) and Neoperla monacha Stark & Sivec ( Stark and Sivec 2008).

Female.

Unknown.

Etymology.

The specific epithet refers to the mesal position of the bifurcate lobe on the ventral surface of the aedeagal tube.

Distribution.

China (Guangxi).

Diagnosis.

The new species appears to belong to a well differentiated subgroup of the montivaga species group ( Zwick 1983) that has as tube characteristics a dark, elongate sclerite dorsally and a bilobed, mostly membranous process ventrally ( Zwick and Sivec 1985). Based on these features, several other species could also be assigned to this diehli subgroup: Neoperla han Stark, Neoperla mnong Stark, Neoperla furcostyla Li & Qin, Neoperla forcipata Yang & Yang and Neoperla yao Stark.

The new species is characterized by the aedeagal tube being short (≤3 × width of bulb) and the ventral, bifurcate process being midlength on the tube. Additionally, the apical half of the sac is clothed with heavy spinules on the dorsal surface. Neoperla diehli has an elongate slender aedeagal tube (length ≥4 × tube width), the ventral processes originate at the apex of the tube, and the heavy spinules are restricted to the tip of the sac (see Fig. 21 in Zwick and Sivec 1985). Neoperla mesostyla is easily distinguishable from other members of the group by its very long sac and relatively short Y-lobe. Neoperla han Stark and Neoperla yao Stark have elongate Y-lobes (Figs 6, 10 in Stark 1987); Neoperla mnong Stark, Neoperla furcostyla Li & Qin, and Neoperla forcipata Yang & Yang have a short or very short aedeagal sac (Fig. 7 in Stark 1987; Figs 2B, C in Li et al. 2013).