Chinoperla nigrifrons ( Banks, 1939 )

Mo, Rao-Rao, Liu, Rui-Jun, Wang, Guo-Quan, Li, Wei-Hai & Murányi, Dávid, 2021, Review of the genus Chinoperla Zwick, 1980 (Plecoptera: Perlidae: Perlinae) from China, European Journal of Taxonomy 775, pp. 62-85 : 71-77

Chinoperla nigrifrons ( Banks, 1939)

Figs 6–10

Ochthopetina nigrifrons Banks, 1939: 449 , fig. 73 (original description).

Sinoperla furcomacula Wu, 1973: 110 , figs 91–93 (original description).

Ochthopetina nigrifrons – Illies 1966: 274 (catalog).

Chinoperla furcomacula – Zwick & Sivec 1980: 130 (transferred from Sinoperla). — Zwick 1982: 168 (synopsis). — Sivec et al. 1988: 54 (provisionally possible conspecifity with C. nigrifrons ). — Sivec & Zwick 1989: 14 (three theories about possible synonymy or distinctiveness with C. nigrifrons ).

Chinoperla nigrifrons – Sivec et al. 1988: 54 (transferred from Ochthopetina, provisionally possible conspecifity with C. furcomacula ). — Sivec & Zwick 1989: 14, fig. 3a, c–e (redescription of male with uneverted aedeagus and female based on types). — Du et al. 1999: 62 (catalog). — Yang & Li 2018: 36 (catalog).

Diagnosis

Head with a heart-shaped dark brown patch and a subtriangular dark brown spot. Male tergum 9 with a trumpet-shaped median sclerite. Hemitergal processes medially indented in lateral view. Aedeagal tube with a T-shaped sclerotized dorsal marking. Aedeagal sac dorsoapically with a low membranous median lobe; ventrobasally with a large patch of spinules; ventroapically with one long and one shorter spine, or the two of equal length; apically with a long straight spine and a large membranous lobe; laterally with dense large, curved spines arranged on each side. Posterior margin of female sternum 8 slightly produced, forming a small subtriangular subgenital plate with an apical notch.

Material examined

Holotype CHINA • ♂; “ Hainan, Ta Han ” [Hainan Province, Qiongzhong Li and Miao Autonomous County, located in Limushan Town ]; 23 Jun. 1935; L. Gressitt leg.; MCZ Type 22693.

Paratypes CHINA • 1 ♀; same locality data as for holotype; 2 Aug. 1935; L. Gressitt leg.; MCZ • 1 ♀; same locality data as for holotype; 13 Jul. 1935; L. Gressitt leg.; MCZ .

Other material

CHINA • 1 ♂, 1 ♀ (holotype and paratype of S. furcomacula ); “ Kwangtung , Hainan , Tung-shih ” [Hainan Province belonging to Guangdong at that time, Wuzhishan City, Tongshen Town ]; alt. 350 m; 27 May 1960; IZCAS • 2 ♂♂; Hainan Province, Baisha Li Autonomous County, Mount Yinggeling ; 19°14′0.24″ N, 109°26′27.96″ E; alt. 430 m; 1 Apr. 2013; Yu-Yu Wang and Yun-Lan Jiang leg.; HIST .

Redescription

Male

ADULT HABITUS ( Figs 6A–B , 8C , 9A ). General color brown. Forewing length 7.7–8.0 mm, hindwing length 6.7–7.1 mm. Head brownish, with a dark brown heart-shaped spot, but specimens from Mount Yinggeling with a long brown band located on the occiput, and with a subtriangular dark brown spot in front of M-line; biocellate, ocelli about 3 diameters apart of each other, slightly closer to each other than to the compound eye; antennae brown. Pronotum trapezoidal, brown with paler lateral margin and with darker, distinct rugosities; anterior corners pointed but posterior corners obtuse. Legs generally brown, proximal part of femora mostly lighter; wings subhyaline and brownish, veins brown, Sc of forewing short, typical of the genus ( Fig. 8C ); cerci brownish.

ABDOMEN ( Figs 6C–E , 8A–B , 9B–E ). Sterna 3–5 with hair brushes. Dark median sclerite of tergum 9 trumpet-shaped, about half as long as the segment, heavily sclerotized, distinctly forked distally with two sharp points. Hemitergal processes slender, about 2.5× as long as basal width, distinctly narrowing subapically; medially indented in lateral view; basal callus fully covered by sensilla basiconica.

AEDEAGUS ( Figs 7 , 10 ). Aedeagal tube partially sclerotized dorsally, forming a distinctly T-shaped marking on the holotype ( Fig. 7A–B ), but marking in specimens from Mount Yinggeling indistinct, well seen only in lateral view ( Fig.10A–B ). Fully everted sac as long as the tube, curved dorsad; ventroapical and dorsoapical surface heart-shaped in specimens from Mount Yinggeling ( Fig. 10 ), less definite in the holotype ( Fig. 7 ); dorsoapical surface with a small bulgy membranous median lobe; a single large spine about as long as ¼ aedeagus length, and a large membranous lobe medially at apex, slightly directed dorsally; ventral surface with a large basal patch of spinule, and one long and one shorter subapical spines ( Fig. 7 ) but in fresh specimens from Mount Yinggeling the two of approximately equal length ( Fig. 10 ); lateroapical part with dense, large and curved spines arranged on each side.

Distribution

China: Hainan Province, found in three counties.

Remarks

We carefully compared the type specimens of O. nigrifrons deposited in MCZ with the illustrations in Sivec & Zwick (1989). The head pattern, direction of antennae and shape of the pronotum of the female paratype collected on 13 July 1935 are consistent with those illustrated in Sivec & Zwick (1989: fig. 3a, d–e). The figures of the terminalia and vagina also refer to the same female paratype, because the second female paratype collected on 2 August 1935 had not been dissected, and its sternum 9 is more narrow. The figure of the male terminalia in Sivec & Zwick (1989: fig. 3b) shows a shallow apical notch of the median sclerite of tergum 9, and tapering and curving hemitergal processes without a straight apical half. These characters are consistent with those in the male paratype, that is not conspecific with the holotype and has been reassigned to C. changjiangensis sp. nov. above ( Fig. 3B–E ). However, the small basal sclerite in the aedeagus of the holotype ( Fig. 7B ) corresponds to that illustrated in Sivec & Zwick (1989: fig. 3c). Therefore, we believe that the half-everted aedeagus of the holotype, the terminalia of the male paratype ( C. changjiangensis sp. nov.), and the head, pronotum, sterna 7–9 and vagina of the female paratype of Chinoperla nigrifrons were redescribed by Sivec & Zwick (1989). Color photographs and illustrations of the male holotype are provided in the present study ( Figs 6–7 ). The characteristics of both female paratypes agree well with the description and illustrations provided by Sivec & Zwick (1989).

We checked the types of S. furcomacula in IZCAS, but the aedeagus of S. furcomacula with the holotype label was difficult to fully evert due to the poor condition of the specimen. Based on the original description and redescription of C. nigrifrons in the present study, we believe that the holotype of S. furcomacula is conspecific with the holotype of O. nigrifrons , and is therefore a junior synonym of C. nigrifrons ( Banks 1939; Wu 1973; Sivec et al. 1988; Sivec & Zwick 1989). The two recently collected males from Hainan Province examined in this study agree well with the type specimens in general characteristics such as head pattern, lateral aspect of the hemitergal lobes, and armatures of the aedeagus. However, these fresh specimens from Mount Yinggeling show slight differences in the head pattern and aedeagus, as they have a long brown posterior band on the head, and the two ventroapical spines of the aedeagal sac are straight and nearly equal in length. We believe this brown occipital band disappears in fully aged adults, such as the holotype. Similar differences were documented in the case of Kamimuria guangxia Li & Wang, 2013 and Neoperla lihuae Li & Murányi, 2014 ( Wang et al. 2013; Li et al. 2014). The differences in the aedeagal armatures can be regarded as intraspecific differences. We provide illustrations of the fully everted sac of the C. nigrifrons holotype and the fresh adults to allow a reliable identification for future studies ( Figs 7 , 10 ).

Unfortunately, the paratype female of S. furcomacula in IZCAS is badly damaged and difficult to study. According to the original description and figures of S. furcomacula ( Wu 1973: fig. 93), the terminalia of the paratype female distinctly differ from those of C. nigrifrons by the unmodified subgenital plate. Sivec & Zwick (1989) drew up three possibilities for the specific identity of this female; we support the third, which suggests that the paratype female may not be conspecific with the holotype of S. furcomacula . Further specimens from Hainan are needed to confirm the identity of the female.

Figures

Fig. 6. Chinoperla nigrifrons (Banks, 1939), ♂, holotype (MCZ Type 22693). A. Adult habitus, dorsal view. B. Head and pronotum, dorsal view. C. Terminalia, dorsal view. D. Cleared terminalia, dorsal view. E. Cleared terminalia, lateral view. Abbreviations: see Material and methods. Scale bars: A = 1.0 mm; B–E = 0.5 mm.

Fig. 7. Chinoperla nigrifrons (Banks, 1939), ♂, holotype (MCZ Type 22693). A. Aedeagus, dorsal view. B. Aedeagus, lateral view. C. Aedeagal sac, ventral view. D. Apex of aedeagal sac, oblique ventral view. Abbreviations: see Material and methods. Scale bars = 0.25 mm.

Fig. 8. Chinoperla nigrifrons (Banks, 1939). A–B. ♂, holotype of C. furcomacula (Wu, 1973) (IZCAS). A. Cleared terminalia, dorsal view. B. Cleared terminalia, lateral view. — C. ♂ from Mount Yinggeling (HIST), forewing. Abbreviations: see Material and methods. Scale bars = 0.5 mm.

Fig. 9. Chinoperla nigrifrons (Banks, 1939), ♂ from Mount Yinggeling (HIST). A. Head and pronotum, dorsal view. B. Terminalia, dorsal view.C. Cleared terminalia, dorsal view. D. Cleared terminalia, lateral view. E. Cleared terminalia, oblique lateral view. Abbreviations: see Material and methods. Scale bars = 0.5 mm.

Fig. 10. Chinoperla nigrifrons (Banks, 1939), ♂ from Mount Yinggeling (HIST). A. Aedeagus, lateral view. B. Aedeagus, dorsal view. C. Aedeagus, ventral view. Abbreviations: see Material and methods. Scale bars = 0.25 mm.

Fig. 3. Chinoperla changjiangensis sp. nov., ♂, paratype of C. nigrifrons (Banks, 1939) (MCZ). A. Adult habitus, dorsal view. B. Head, dorsal view. C. Pronotum, dorsal view. D. Cleared terminalia, dorsal view. E. Cleared terminalia, lateral view. F. Aedeagus, dorsal view. Abbreviations: see Material and methods. Scale bars: A = 1.0 mm; B–F = 0.5 mm.