Nagiella tristalis Matsui & Naka, 2021

Matsui, Yuki, Naka, Hideshi & Jinbo, Utsugi, 2021, DNA barcoding and morphology reveal a new cryptic species of Nagiella (Lepidoptera, Crambidae, Spilomelinae) from Japan, ZooKeys 1023, pp. 171-192 : 171

Nagiella tristalis Matsui & Naka sp. nov. Figures 2A, B , 3A-C , 6A-C

Type material.

Holotype. ♂, Japan: Sourokubara, Tottori City , Tottori Pref., 35.46°N, 134.11°E, 110 m, 7 Nov. 2019 (F1 emerged), Y. Matsui leg. , preserved in National Museum of Nature and Science, NSMT-I-L-75637. Paratypes. 2♀ 3♂, Same locality as holotype, 5 Mar. 2018, 6 Apr. 2018, 4 May 2018, 13 Sep. 2018 (emerged), H. Naka, and Y. Matsui leg. ; 1♀ 3♂, Setagura, Tottori City , Tottori Pref., 35.47°N, 134.12°E, 45 m, 7-22 Mar. 2019 (emerged), 23 Sep. 2019 (F1 emerged), H. Naka leg. ; 2♀, Uemachi, Tottori City , Tottori Pref., 35.50°N, 134.24°E, 40 m, 5 and 10 Feb. 2019 (emerged), Y. Matsui leg. ; 1♀, Mt Honjin-yama, Tottori City , Tottori Pref., 35.51°N, 134.26°E, 110 m, 24 Jun. 2012, Y. Matsui leg. ; 1♂, Tokumaru, Yazu Town , Tottori Pref., 35.37°N, 134.34°E, 145 m, 20 Aug. 2014, H. Naka leg. Other specimens. 1♀, Mt Takao, Tokyo To , 19 Jul. 1960, T. Ebato leg. (NSMT-I-L-75536) ; 1♂, Nashimoto , Shizuoka Pref., 23 May 1953, T. Ebato leg. (NSMT-I-L-75538) ; 1♂, ditto, 5 Jun. 1959, T. Ebato leg. (NSMT-I-L-75537) ; 1♂, ditto, 10 Jun. 1961, T. Ebato leg. (NSMT-I-L-75539) ; 2♂, ditto, 24 Aug. 1966, T. Ebato leg. (NSMT-I-L-75534, 75535) ; 1♀, Kuragari-Valley, Nukata Town , Aichi Pref., 26 Jun. 1993, A. Sasaki leg. (NSMT-I-L-75593) ; 1♂, Sugano, Tokuyama City , Yamaguchi Pref., 27 Jun. 1993, T. Ikenoue leg. (NSMT-I-L-75594) ; 1♀, Shimomyo, Aira Town , Kagoshima Pref., 28 May 1992, Y. Yanagita leg. (NSMT-I-L-75596) ; 1♀, Kamitsuru, Izumi City , Kagoshima Pref., 14 Jul. 1992, Y. Yanagita leg. (NSMT-I-L-75595) ; 1♂, Mt Ishizukadake , I. Yakushima, Kagoshima Pref., 5 Aug. 1958, B. T. leg. (NSMT-I-L-75607) ; 1♂, Nagata, I. Yakushima , Kagoshima Pref., 3 Oct. 2006, M. Owada and T. Fukuda leg. (NSMT-I-L-75606) ; 1♀, Chuo-rindo, Uken, I. Amamiohshima , Kagoshima Pref., 13 Oct. 1988, M. Owada leg. (NSMT-I-L-75541) ; 3♂, ditto, 22 Apr. 2009, M. Owada leg. (NSMT-I-L-75609 to 75611) ; 1♀, Kinsakubaru, Naze, I. Amamiohshima , Kagoshima Pref., 11 Oct. 1988, M. Owada leg. (NSMT-I-L-75542) ; 1♂, Mt Yuwan-dake , I. Amamiohshima, Kagoshima Pref., 12 Oct. 1988, M. Owada leg. (NSMT-I-L-75543) ; 1♀, Naze, I. Amamiohshima , Kagoshima Pref., 25 Jun. 1968, Y. Kishida leg. (NSMT-I-L-75540) ; 1♂, Shinokawa, Setouchi, I. Amamiohshima , Kagoshima Pref., 21 Apr. 2009, M. Owada leg. (NSMT-I-L-75608) ; 1♂, Mikyo, I. Tokunoshima , Kagoshima Pref., 31 Oct. 1992, M. Owada leg. (NSMT-I-L-75544) ; 1♂, Gogayama , I. Okinawajima, Okinawa Pref., 30 Mar. 1974, T. Naito leg. (NSMT-I-L-75612) ; 1♀, Seifuautaki, Chinen-son , I. Okinawajima, Okinawa Pref., 16 Aug. 1980, R. Sato leg. (NSMT-I-L-75613) ; 1♂, same data as for preceding (NSMT-I-L-75614) ; 1♀, Ôkuni-bashi, Kunigami-son, I. Okinawajima , Okinawa Pref., 21 Apr. 2001, A. Sasaki leg. (NSMT-I-L-75615).

Etymology.

The specific epithet refers to the darker wing color in comparison to that of N. inferior , and the habitat of this species is a shaded place.

Diagnosis.

This new species is similar to N. inferior and N. quadrimaculalis , also distributed in Japan, but it can be distinguished by the following characters: length of forewing 12.0-13.0 mm; vertex with erect, dull-orange scales; subdiscal white spot of forewing rounded, small, and blurry; base of discal cell of hindwing identical to ground color; dorsal margin of valva of male genitalia slightly incurved subapically; anterior apophysis of female genitalia straight and narrow; signum of female genitalia nearly elliptical, larger than in N. inferior (diameter 0.09-0.14 mm). This species is also similar to N. occultalis and N. bispina distributed in China, but N. occultalis has the following differences: subdiscal white spot of forewing narrowed or elongated, tuba analis of male genitalia sclerotized, gnathos of male genitalia elongated and narrow at the base; N. bispina exhibits the following differences: gnathos of male genitalia absent, phallus of male genitalia with a hook-shaped cornutus, corpus bursae of female genitalia with two thorn-like signa. From N. hortulatoides , the new species can be easily distinguished by the wing maculation.

Description

(Fig. 2A, B ). Head: frons brownish grey, smooth. Vertex with erect, dull-orange scales. Labial palpus upturned, dorso-laterally dark brown, ventro-mesally pale white. Antenna dark brown; flagellum filiform with golden cilia ca 1/4 the diameter of flagellum in male.

Thorax and abdomen: dorsally brownish grey; patagium and tegula with ochreous brown. Ventrally milky white.

Wings: length of forewing 12.0-13.0 mm. Ground color of both wings brownish grey, with a large comma-shaped white spot at end of discal cell (the bases of R 5 to M3), that of the hindwing somewhat small; cilia concolorous with ground color; postmedial line obscure. Subdiscal white spot of forewing rounded, small and blurry. Base of discal cell of hindwing concolorous with ground color.

Male genitalia (Fig. 3A-C ): uncus short, subtrapezoid, blunt on posterior margin. Gnathos nearly triangular, short and small, apex blunt. Tuba analis elongate, not sclerotized, length ca 0.6 times that of valva. Transtilla subtriangular, completely connected medially. Saccus short, anterior margin rounded. Valva somewhat narrow, length ca 3.3 times that of width, dorsal margin slightly incurved subapically; costa more or less inflated with several setae at apex; clasper large, down curved, the apex blunt. Phallus cylindrical, without cornutus.

Female genitalia (Fig. 6A-C ): ovipositor lobe oblong, setose. Anterior apophysis ca 2 times length of posterior apophysis, narrow, almost straight, with triangular expansion near base. Antrum trapezoid, sclerotized at collar. Ductus bursae almost equal in length to corpus bursae, membranous with wrinkles, slightly narrowed at posterior end. Corpus bursae pear-shaped, membranous; signum nearly elliptical, sparsely covered with denticles.

Biology.

In Honshu, Japan, adults are found in May to September, and they are considered bivoltine. They appear to be hardly attracted to light. Larvae feed on Rubus buergeri and the middle instar larvae overwinter in its leaves.

Distribution.

Japan: Honshu (Tokyo, Shizuoka, Aichi, Tottori, Yamaguchi), Kyushu (Kagoshima), Ryukyu Islands (Yakushima, Amamioshima, Tokunoshima, Okinawajima) .

Remarks.

The shapes of the uncus and gnathos show intraspecific variations, i.e., in several specimens, the posterior margin of the uncus is slightly notched medially, and the projection of the gnathos is smaller than that shown on Figure 3B . Also, in N. inferior , the shape of the gnathos varies similarly as in N. tristalis . Therefore, these characters are unsuitable for diagnosis of N. tristalis and N. inferior . Similarly, Ullah et al. (2017) proposed the shape of the claspers as a diagnostic character for distinguishing between N. occultalis and N. quadrimaculalis , but we could not find any clear difference among N. tristalis , N. inferior , and N. quadrimaculalis , because of the overlap in intraspecific variations.

Figures

Figure 2. Nagiella adults, dorsal view A N. tristalis sp. nov. male B N. tristalis sp. nov. female C N. inferior male D N. inferior female E N. quadrimaculalis male F N. quadrimaculalis female. Scale bars: 5 mm.

Figure 3. Male genitalia of Nagiella tristalis sp. nov. A whole genitalia B gnathos, magnified view C apex of valva, magnified view.

Figure 6. Female genitalia of Nagiella tristalis sp. nov. A whole genitalia B anterior apophysis, magnified view C signum, magnified view.