Neoperla dashahena Du, 2005: 51.

Adult habitus: General body colour brown. The head is pale yellow with two ocelli. The ocelli are black, surrounded by a quadrate brown area. An inverted brown triangle is present centrally on the frons (Fig. 1A); Pronotum is light brown and trapezoidal in shape; Abdominal segments and cerci pale brown.

Figure 1.  

Neoperla dashahena Du, 2005 from Guizhou, male. A head and pronotum, dorsal view; B abdomen, dorsal view; C abdomen, lateral view.

Male: The middle posterior part of tergite 7 has square or quadrate areas that are slightly raised, the posterior margin of which is sclerotised and has a small sensilla basiconica patch. As specimens of this species have been preserved in alcohol for nearly 20 years, lateral sclerotised areas give the impression of a broad, shallow arc. Tergite 8 bears a recurved tongue-like process with small spines at the distal margin. Hemitergal processes of tergite 10 up-curved, extending backwards to the central process of tergite 9, tip rounded. (Fig. 1B-C).

The medial pair of spinule-covered projections appear to be part of the penis base. The endophallus starts distal of these lobes. The connected distal patch of spinules is located anti-apically on the endophallus. (Fig. 2B-C and Fig. 3A). Larger spinule patch on the dorsal surface of the middle part of the everted endophallus (Fig. 2A and Fig. 3B), with a row of small spines on the ventral surface of the proximal endophallus (Fig. 2C and Fig. 3C).

Figure 2.  

Neoperla dashahena Du, 2005 from Guizhou, male. A penis base and everted endophallus, dorsal view; B penis base and everted endophallus, lateral view; C penis base and everted endophallus, ventral view.

Figure 3.  

Neoperla dashahena Du, 2005 from Guizhou, male. A ventral surface of anti-apical endophallus, ventral view; B apical half of everted endophallus, dorsal view; C apex of everted endophallus, ventral view.

China (Guizhou).

Neoperla dashahena was originally assigned to the montivaga species group (Zwick 1983, Zwick 1986) with the penis having incomplete sclerotisation in the ventral aspect. Zwick (2023) recently made this grouping obsolete and erected two subgenera, Neoperla (Borneella) and Neoperla (Formosita) Klapálek.

Due to the presence of paired, ventral spiny lobes at the apex of the penis base, we now assign N. dashahena to the N. (Formosita) lushana-group. The penis of N. dashahena is most similar to Neoperla latamaculata Du, 2005 and Neoperla yaoshana Li, Wang & Lu, 2011. In N. dashahena, a larger spinule patch exists on the dorsal surface of the everted endophallus, with a row of small spines on the ventral surface of the endophallus. In N. latamaculata, the dorsal surface of the everted endophallus has a "V"-shaped spinules patch. In N. yaoshana, the apical half of the everted endophallus bears a field of fine dorsal and ventral spinules separated by a lateral membranous area.

Neoperla bituberculata Du, 2000: 1.

Adult habitus: General body colour brown. Head mostly yellowish-brown, with a black marking covering an ocellar triangle; Compound eyes black; Pronotum disc brown, mid-line darker, margins pale (Fig. 4A).

Figure 4.  

Neoperla bituberculata Du, 2005 from Guizhou, male. A head and pronotum, dorsal view; B abdomen, dorsal view; C abdomen, dorsal view.

Male: The anterior edge of tergite 7 is concave in the middle and forms a "Y"-shape with one projecting sclerite. In the posterior part of the tergite, there is a raised process that slightly bifurcates to form a median ridge covered by many small sensilla basiconica. Tergite 8 has a tongue-shaped upcurved process, with many sensilla basiconica at the distal margin. Hemitergal processes of tergite 10 sclerotiszed and finger-like, a subapical protrusion is present (Fig. 4B–C).

Penis base well sclerotised and its dorsal surface near the tip has small spines (Fig. 5). The everted endophallus curves ventrally, with a tube-like inner sclerite apically. The entire endophallus is densely covered with slender golden-brown spines.

Figure 5.  

Neoperla bituberculata Du, 2005 from Guizhou, male. Penis base and everted endophallus, lateral view.

China (Guizhou).

This species is similar to Neoperla infuscata Wu, 1935, but their everted endophallus are quite different. In N. bituberculata, there are many golden-brown spines on the endophallus, while in N. infuscata, the endophallus bears only a few small spines. In addition, the tergite 7 of the N. bituberculata has two small lobes, which is also used for the etymology for this species.

Javanita costalis Navás, 1932: 925. Secondary homonym of Formosina costalis Klapálek (Zwick 1988)

Neoperla mnong Stark, 1987: 48. Holotype ♂ (California Academy of Sciences). Di Linh, Vietnam

Neoperla angustilobata Zwick, 1988: 404. Holotype ♀ (Muséum National d’Histoire Naturelle), New Synonymy

 China (Guizhou, Hunan, Jiangxi, Guangdong, Guangxi); Vietnam; Thailand.

Stark and Sivec (2008) mentioned that N. mnong was first described as Javanita costalis (Navas 1932) from a female specimen and later described as a new species from a male specimen (Stark 1987). Due to their similar penis, N. mnong, N. han Stark, 1987, N. furcostyla Li & Qin, 2013, N. forcipata Yang and Yang, 1992 and N. yao Stark, 1987 were classified into the diehli subgroup (Wang et al. 2013). Subsequently, these species were assigned to the N. (Formosita) diehli complex (group) (Zwick 2023). It needs to be corrected as the penis of N. mnong was misidentified as N. dao Stark & Sivec, 2008 in Zwick (2023), on page 116, figure 67. The diehli complex (group) is primarily distributed in low-latitude regions of East Asia to South Asia, including southern China (Guangdong, Guangxi, Yunnan, Hainan etc.) to areas spanning Vietnam, Thailand and Indonesia.

This article records for the first time the distribution of this species in Guizhou, Hunan and Jiangxi Provinces of China, covering most of the southern region of China to Vietnam, indicating that it is a species that is widely distributed in coastal areas of Southeast Asia (Fig. 6). In China, this species is primarily concentrated in the Nanling Mountains, but records from Guizhou and Hunan suggest that it may also occur in adjacent inland provinces to the west (or north) of the Nanling Mountains. In the future, more widespread species or new distribution records of the diehli complex (group) may be reported. We provide additional illustrations (Figs 7, 8) to aid in the recognition of this species.

Figure 6.  

The distribution of Neoperla mnong Stark, 1987. The white squares indicate the collection places. China: 1. Hunan, Huitong; 2. Guizhou, Leishan; 3. Jiangxi, Longnan; 4. Guangdong, Shixing; 5. Guangxi, Jinxiu; 6. Guangdong, Conghua; Vietnam: 7. Con Cuong; 8. Pleiku; 9. An Khe; 10. Dak Son; 11. Di Linh; 12. Thailand, Chanthaburia.

Figure 7.  

Neoperla mnong Stark, 1987, male. A head and pronotum, dorsal view; B abdomen, dorsal view.

Figure 8.  

Neoperla mnong Stark, 1987, male. A penis with partly everted endophallus, lateral view; B penis base and everted endophallus, lateral view.