Lethe langsongyuni, Huang & Wang & Fan, 2019

Huang, Si-Yao, Wang, Min & Fan, Xiao-Ling, 2019, A new species of the genus Lethe Hübner, 1819 from Yunnan, China (Lepidoptera, Nymphalidae, Satyrinae), Zootaxa 4700 (4), pp. 464-470 : 465-469

Lethe langsongyuni sp. nov.

( Figs. 1–4 , 15 )

Type material. Holotype: male, altitude 2700 m, 18. VII. 2018, Weixi County, Diqing Tibetan Autonomous Prefecture, Yunnan Province, P. R. China, leg. Shi-fang Mo & Zhi-peng Miu ( SCAU) . Paratype: 1 male, 12. VII. 2009, Pantiange Town , Weixi County, Diqing Tibetan Autonomous Prefecture, Yunnan Province, P. R. China, leg. Hongliang Shi ( CHH) ; 1 male, 1.VIII. 2018, altitude 2700 m, Badi Town , Weixi County, Diqing Tibetan Autonomous Prefecture, Yunnan Province, P. R. China, leg. Hao Huang ( CHH) .

Diagnosis. L. langsongyuni sp. nov. is more closely related to L. liae Huang, 2002 ( Figs. 5–6 , 16 ), L. proxima Leech, 1892 ( Figs. 7–8 , 17 ) and L. umedai albofasciata Huang, 2002 ( Figs. 9–10 , 18 ) than to the other members of trimacula -group, but it can be distinguished from all these three species in having postdiscal band on the forewing under side narrow and smoothly curved outwards in space 3 and the pale zone between the postdiscal band and subapical ocellus unicolor, wider and more confluent at outer margin.

Description. Male. Length of forewing 27–30 mm (27 mm in holotype). Body as in the ground plan of the trimacula -group. Upper side of forewing ground color brown; subapical zone with a large black ocellus, which is ringed by creamy white and pupillated by a white dot; a vestigial pale band anterior to the ocellus extending from costa to space 2, curving near in space 3. Under side of forewing ground color grayish brown; two black transverse lines crossing the discoidal cell, with one in the middle and another one at end of it; postdiscal band narrow, extending from costa to vein 2, curving at the middle of space 3; subapical ocellus smaller than upper side; two arrowshaped white patches presenting beyond the ocellus. Hindwing upperside ground color as forewing; two prominent ocelli presenting in postdiscal zone in spaces 2–3, with trace of ocelli in space 1 and 4. Under side of hindwing ground color brown dusted by white scales; subbasal and discal zone with irregular zigzag black lines; end of discoidal cell dusted by black; postdiscal zone with seven ocelli from space 1 to 7.

Male genitalia. Tegumen simple. Uncus rather long, swollen at the middle and gradually narrowing towards tip. Gnathos long and slender, even in width. Saccus nearly as long as tegumen, slightly shorter than gnathos. Valva long, broad at base and gradually narrowing towards tip, ending with a narrow and sharp apex. Aedeagus moderately long, with its dorsal wall pointed at tip and several small teeth presenting at its ventral side in lateral view.

Female. Unknown at present.

Distribution. Currently this new species is only known from Weixi County located in northwestern Yunnan Province, southwestern China.

Etymology. The specific name langsongyuni is dedicated to Dr. Song-yun Lang (Beibei, Chongqing, China) who is an expert in Nymphalidae of China.

Remarks. L. langsongyuni sp. nov. can be distinguished from L. proxima , L. liae and L. umedai albofasciata by combination of the following characters: 1) under side of forewing with postdiscal band much narrower than L. proxima , similar to that in L. liae and L. umedai albofasciata ; 2) under side of forewing with postdiscal band gently curving outwardly in space 3 as in L. proxima , while that curving inwardly in space 3 in L. liae and L. umedai albofasciata ; 3) the pale zone right between the postdiscal band and subapical ocellus being unicolor, wider, mistier and more confluent at outer margin, while that in L. liae and L. umedai albofasciata much narrower, clearer and more zigzag at outer margin and that in L. proxima white near the costa and gradually becoming pale yellow towards tornus; 4) in male genitalia uncus swollen before the middle point as in L. proxima , while even in width in L. liae and swollen right at the middle point in L. umedai albofasciata ; 5) valva much shorter than that in L. proxima , similar to that in L. liae and L. umedai albofasciata ; 6) tip of valva in dorsal view longer, similar to L. liae and L. umedai albofasciata , while that in L. proxima shorter. From L. trimacula Leech, 1890 ( Figs. 11–12 , 19 ), L. langsongyuni sp. nov. can be easily distinguished in having the postdiscal band narrow and gently curving outwards in space 3 on forewing under side (postdiscal band broad and shifting inwards in space 3 in L. trimacula ) and pale zone between the postdiscal band and subapical ocellus wider, mistier and more confluent at outer margin (pale zone narrower and more clearly defined in L. trimacula ). From L. butleri Leech, 1889 ( Figs. 13–14 , 20 ), L. langsongyuni sp. nov. can be simply distinguished by the subapical twin ocelli on hindwing underside (single ocellus in L. butleri ).

So far, four taxa, L. langsongyuni sp. nov., L. proxima Leech, 1892 , L. liae Huang, 2002 and L. umedai albofasciata Huang, 2002 , are allopatric with one another ( Fig. 21 ). Although the external and genitalic features of L. langsongyuni sp. nov. possess some characters similar to those found in L. liae Huang, 2002 , L. proxima Leech, 1892 and L. umedai albofasciata Huang, 2002 , respectively, none of these species has been reported in Weixi County or adjacent area before, suggesting that the existence of L. langsongyuni sp. nov. is definitely not the result of interspecific hybridization. Moreover, the concentration of sympatric species in the same group in southwestern China provinces is frequently seen in other species group of the genus Lethe , such as L. manzorum -group, L. minerva - group and L. baladeva -group ( Lang, 2017), and based on our observation, some of them even fly together at the same time, and no hybrid offspring in these groups has ever been found, meaning all the members of these groups have already evolved into different species which cannot produce reproductive offspring between any two of them. Similarly, L. proxima Leech, 1892 , L. trimacula Leech, 1890 and L. umedai Koiwaya, 1998 might theoretically meet each other in somewhere in Sichuan Province and Chongqing City as indicated by Lang (2017), but no hybrid offspring has ever been encountered in these two sites, which indicates that the members within trimacula -group also have already differentiated into distinct species though their external and genitalic feature are still very similar, and this conclusion is also applicable to L. langsongyuni sp. nov.

Within the whole trimacula -group, L. butleri Leech, 1889 is rather unique for the following characters: 1) both wings rather short and stout; 2) forewing under side with postdiscal band shifting outwards near costa; 3) hindwing under side subapical ocellus single; 4) hindwing under side postdiscal band not zigzag, and 5) male genitalia with valva tip forming a large hook bending inwards. These characters are not found in other species in this group and other congeners, which suggests that its true systematic position requires further study.

Figures

FIGURE 21. Distribution map of Lethe trimacula-group studied in the present work. Distribution records are taken from Koiwaya (1998), Huang (2002), Lang (2017) as well as the results of this work.

FIGURES 1–8. Adults of Lethe trimacula-group. 1–2, L. langsongyuni sp. nov., holotype, Weixi (SCAU); 3–4, L. langsongyuni sp. nov., paratype, Badi, Weixi, by courtesy of Mr. Hao Huang (CHH); 5–6, L. liae Huang, holotype, Qiqi, Nujiang, by courtesy of Mr. Hao Huang (CQEC); 7–8, L. proxima Leech, Mt. Erlang, Tianquan (SCAU); 1, 3, 5, 7: upper side; 2, 4, 6,8: under side. Scale=1 cm.

FIGURES 15–20. Male genitalia of Lethe trimacula-group 15, L. langsongyuni sp. nov., holotype; 16, L. liae Huang, holotype, by courtesy of Mr. Hao Huang; 17, L. proxima Leech; 18, L. umedai albofasciata; SATY0512, by courtesy of Dr. Song-yun Lang; 19, L. trimacula Leech; 20, L. butleri Leech. a=genitalia capsule in lateral view with left valva removed (figs. 13–14, 16) or right valva removed (fig. 15); b=aedeagus in lateral view; c=aedeagus in dorsal view; d=tip of left valva in dorsal view; scale=1 mm.

FIGURES 9–14. Adults of Lethe trimacula-group 9–10, L. umedai albofasciata, Xiongdang, Dulongjiang, SATY0512, by courtesy of Dr. Song-yun Lang (CLSY); 11–12, L. trimacula, Yingjing, Sichuan (SCAU); 13–14, L. butleri, Qingyuan, Zhejiang (SCAU); 9, 11, 13: upper side; 10, 12, 14: under side. Scale=1 cm.