New species and records of the stonefly genus Neoperla (Plecoptera, Perlidae) from Jinhuacha Nature Reserve, Guangxi of China

Abstract Two new Neoperla species (Neoperla mesospina, Neoperla latispina) are described from the adult male stage from the Jinhuacha Nature Reserve, Guangxi of China. The new species are compared with similar taxa. Taxonomic remarks are also provided for N. transversprojecta Du & Sivec and N. yao Stark. The latter species is newly recorded for Guangxi.


Material and methods
The specimens used in this study were collected by light trap. Types and other examined material are deposited in the Insect Collection of Henan Institute of Science and Technology (HIST), Xinxiang, and the Entomological Museum of China Agricultural University (CAU), Beijing. They were examined with the aid of a Motic SMZ 168 microscope and the color illustrations were captured using digitalized software Motic Images Advanced 3.2. All specimens were kept in 75% ethanol. Aedeagi were everted using the cold maceration technique of Zwick (1983). Terminology follows that of Sivec et al. (1988). All the scale lines in the figures stand for 0.5 mm. Male. Forewing length 12.6 mm. Distance between ocelli about 1.5× as wide as diameter of the ocellus. Head pale yellow, slightly wider than pronotum, with a black area covering ocelli which extends forward to contacting a quadrate black stigma on frons (Fig. 1a); compound eyes black and antennae dark except scape pale; maxillary palpi brownish. Pronotum with obscure rugosities and pale lateral margins, meso-and metathorax mostly brown (Fig. 1a); wing membrane subhyaline, veins brown; legs dark brown with femora pale brown, but distal fourth of foreleg femora dark brown (Fig. 1e).

Neoperla latispina
Terminalia. The posterior margin of tergum 7 with a trapezoidal sclerotized area extended into a rounded quadrate process covered with distal sensilla basiconica (Fig. 1b).  Tergum 8 with two median weak humps covered by sensilla basiconica (Figs 1b). Tergum 9 with two patches of sensilla basiconica. Hemitergal processes of tergum 10 sclerotized, with rod-like base and sharp apex (Fig. 1b). Aedeagal tube membranous with a weak basodorsal sclerite, apically with a pair of separate dorsal spinous lobes covered by small spines connected with two lateral spinous bands, in lateral view the lobes plump and nipple like (Figs 1c-d, 2). Aedeagal sac slightly longer than tube, essentially straight along with tube in outline; two spinulose dorsal patches present at slightly swollen base, single ventral lobe without spines, located near midlength of sac, a pair of mesolateral protrusions rounded, covered by large spines and two nearby elevated dorsal lobes triangular in lateral view covered with tiny spines; distal portion of sac with two rows of large spines which extend laterally below the apical fine spinules (Fig. 2).
Female. Unknown. Etymology. The specific epithet refers to the lateral spinous patch of aedeagal sac. Distribution. China (Guangxi). Diagnosis and remarks. Neoperla latispina belongs to oculata species complex defined by Zwick (1986) in the montivaga species group (Zwick 1983) which includes species bearing a similar T7 lobe and several lobes, protrusions or finger shaped extensions of the aedeagal sac (see figs 1-2 and figs 51-63 in Zwick 1986 for comparison). This species shares dorsal lobe characteristics of the aedeagal tube with N. securifera Zwick 1986and N. multilobata Zwick 1986(figs 57 & 59 in Zwick 1986. Neoperla latispina also shares a straight outline of the extruded aedeagus with N. multilobata whereas the sac of N. securifera stands at right angle to tube. However, the dorsal lobes of aedeagal tube in N. latispina are paired but that of N. multilobata is single. Additionally, N. latispina bears only single ventral lobe near midlength while N. multilobata has spinous ventrobasal and ventrodistal lobes ( fig. 59 in Zwick 1986). Male. Forewing length 11.1-11.3 mm. Distance between ocelli about as wide as diameter of the ocellus. Head mostly yellow brown, lateral margins and frons pale, a subquadrate dark area covering ocelli, slightly wider than pronotum; antennae brown; compound eyes dark; mouthparts brown (Fig. 3a). Thorax brownish with darker median stripe and scattered rugosities, legs brown; wings pale. Abdomen brownish yellow.

Neoperla mesospina
Terminalia. Tergum 7 with an elevated trapezoidal median process at posterior margin, which is covered by many tiny sensilla basiconica. Process of tergum 8 moderately sclerotized, recurved backward and tougue-shaped, lateral marings with tiny spines. Tergum 9 without sensilla patches. Hemitergal processes of tergum 10 strongly sclerotized and with slightly curved apex (Figs 3a, b). Aedeagal tube long and slender, relatively straight and moderately sclerotized, medially with a nipple-like process in ventral surface; everted sac strongly curved ventrad as a loop, about half as long as tube, irregular rows of small to median sized spines present along dorsal and lateral surfaces from medial portion to apex of the sac (Figs 3d & 4).
Female. Unknown. Etymology. The specific epithet refers to the location of the nipple-like process on the aedeagal tube.

Diagnosis and remarks.
The new species seems closely related to N. dao Stark & Sivec, 2008, a recently described species from Vinh Phu Province of Vietnam. They are very similar in head pattern, general features of male terminalia and the aedeagal tube. However, the new species can be easily separated from N. dao Stark & Sivec by the relatively long (about half as long as tube) and strongly curved aedeagal sac in lateral view. In N. dao Stark & Sivec, the sac is very short, somewhat straight and triangular in outline ( fig. 22 in Stark and Sivec 2008). There are no other Chinese species of Neoperla that appear related to N. mesospina.

Distribution. China (Guangxi).
Remarks. This species was originally described by Du and Sivec (2004). 2 males were available to the present study and only the tip of sac shows a slight difference with original drawing ( fig. 4 in Du and Sivec 2004). The dorsal patch of subapical spines in the present material seems prominent than as in original drawing.  Stark, 1987 http://species-id.net/wiki/Neoperla_yao Fig. 6 Neoperla yao Stark, 1987 Remarks. This species was originally described by Stark (1987) from Vietnam and China based on three males (two from Vietnam, one from China), its female was recently associated (Stark and Sivec 2008). One male was available to the present study and the tip of sac seems slightly hooked with sharper apex that appears somewhat blunt in original drawing ( fig. 6 in Stark 1987).

Concluding remarks
Previous studies on the genus Neoperla from Guangxi include Wu (1948), who described Neoperla curvispina and N. rotunda from Mountain Yaoshan. Subsequently Yang and Yang (1990) described Neoperla wui from Jinxiu, and Du (1998) reported the presence of Neoperla mnong Stark, 1987 from Guangxi. Du and Sivec (2004) summarized the stonefly fauna from Mountain Shiwandashan in Guangxi, describing three new Neoperla species and adding two other records. Recently, two new species were added from Guangxi by Li et al. (2013b) and Wang et al. (2013). However, there was still no record of the genus Neoperla or other stoneflies in previous studies on the insect fauna of the Jinhuacha Nature Reserve. In this study, two additional new species are described and a new record for Guangxi is recorded. Therefore, there are up to 14 known Neoperla species from Guangxi presently.