Diduga nantouensis Bayarsaikhan & Bae, 2021

Bayarsaikhan, Ulziijargal, Heppner, John B., Kwon, Hyung-Wook & Bae, Yang-Seop, 2021, Review of the genus Diduga Moore (Lepidoptera, Erebidae, Arctiinae) of Taiwan with descriptions of two new species, Zootaxa 5032 (2), pp. 216-224 : 219-223

Diduga nantouensis Bayarsaikhan & Bae , sp. n.

( Figs 2 , 4 , 6 , 8 , 9 )

Type materials. Holotype: 1 ♂, Taiwan, Nantou Co., Yu-Chi, Wu-Cheng Hwa-Lung, Ca 600m, 18–19.XI.1997 (YS Bae & KT Park), Gen. Slide No. INU-1910 T (Coll. INU) . Paratypes. (42 ♂, 11 ♀) Taiwan : 1 ♀, same with holotype, Gen. Slide No. INU-1909 T ; 1 ♂, 1 ♀, Wulai (550m), Taipei Co., 1–2.VII.1996 (KT Park et HK Lee) , Gen. Slide No. INU-1912 T (female), 1913 T (male) (Coll. INU) . 1 ♂, Nantou Co., Lushan-spa , 29.VII.1985 (Y. Kishida leg.), Gen. Slide No. CYKJ-10031 T (Coll. Y. Kishida) . 5 ♂, 1♀, Ilan Co., Mingshyr Rec. Area (1250m), 9–10.VII.1996 (JBH & HYW), adult photos 14582m , 14583f, Gen. Slide No. JBH- 3909m ; 1 ♂, Hsinchu Co., Kuangwu (2000m), 18–25.VIII.1988 (JBH & HYW), Gen. Slide No. JBH- 3917m ; 16 ♂, 2 ♀, Kaohsiung Co., Shanpin For Sta. (750m), near Liukuei, 16–23.III.1990 (JBH & HYW), adult photo 14596m , Gen. Slide No. JBH- 3901m ; 1 ♀, same site, 4–7.XI.1984 (JBH & HYW), adult photo 14597f; 1 ♀, Kaohsiung Co., Tienchih (2210m), 24.X.1984 (JBH & HYW), Gen. Slide Co. JBH-3940f ; 1 ♂, 1 ♀, Taichung Co., Kukuan (700m), 6.VII.1985 (JBH & HYW), adult photo 14603m ; 5 ♂, Taipei Co., Fushan (650m), 4–11.IV.1990, (JBH & HYW), adult photo 14607m ; 1 ♂, Taipei Co., Wulai (200m), 17–19. VI.1985 (JBH & HYW), adult photo 14606m , Gen. Slide No. JBH- 3908m ; 1 ♂, Taoyuan Co., Upper Palin (1500m), 7–9.VII.1985 (JBH & HYW) (Coll. Dr. Heppner) ; 1 ♂, 2 ♀, Pingtung Co., Kenting Park (255m), 9–15.III.1990 (JBH & HYW) ; 2 ♂, same site, 23–28.IV.1989 (JBH & HYW); 7 ♂, 1 ♀, same site, 29–31.VIII.1983 (JBH & HYW), adult photos 14580m and 14581f, Gen Slide No. JBH- 3906m (Coll. Dr. Heppner).

Diagnosis. The wing pattern of this species is hardly distinguishable from many others of the genus Diduga . The male genitalia structure of the new species is similar to D. nigridentata ( Bayarsaikhan & Bae, 2019: fig. 13) and D. simianshana (Zhao & Han, 2020a: fig. 14), but can be distinguished from the latter by the larger, rounded apical prominence of left valva (half size of left valva), with a stout, straight, blunted subapical spine in upper angle and a short (half size of the upper large spine), thin lower angle’s process without apical spine, and a large, almost straight left basal projection of costal margin; in the right valva, an arch-shaped prominence (2x smaller than left valva’s) of upper angle with a stout, weakly bent, blunted spine and stout, short finger-shaped process (about 4x shorter than bent spine) in basal area of bent spine, and a short, thin lower angle’s process with a slender apical spine, which is the almost same length with upper angle’s bent spine, and a large right basal projection of costal margin slightly waved. In D. nigridentata , the irregularly truncated apical prominence of the left valva is at least 4x shorter than valva, with a slender, weakly bent, sharply pointed subapical spine in upper angle and a short, slender lower angle’s process with a slightly bent, slender apical spine (length of process and spine half of a large upper spine), and a large left basal projection of costal margin strongly angled apically, and the apical area of costal margin in left valva strongly sclerotized; in right valva, a stout, finger-shaped costal process of the upper angle of valva with a slender, weakly waved, sharply pointed subapical spine inwardly, and a short, thin lower angle’s process with a slender, curved apical spine (it is shorter than upper angle’s spine), and a rounded, small (almost 3x shorter than left valva’s) prominence between upper and lower processes, and a large right basal projection of costal margin strongly angled. In D. simianshana , both valvae without rounded apical prominence, but two apical spines, which are the almost same size to short, slender lower angle’s process with a slightly bent, slender apical spine, and two basal projections of costal margin longer than tegumen. The male abdomen has a simple lyre-like dorsal apodeme on the pregenital segment ( Fig 8 ), contrasting with a very complicated ventral structure in D. taiwana sp. n. ( Fig 7 ). The female pregenital sternite has a strongly sclerotized band across the margin of the sternite ( Fig 9 ), leading laterally on each side to a sclerotized pouch on the intersegmental membrane, contrasting with the unstructured sternite found in females of D. tiawana sp. n.

This species is very similar to D. hanoiensis ( Bayarsaikhan & Bae, 2019: fig. 16) and D. simianshana (Zhao & Han, 2020a: fig. 14) in features of the female genitalia, but can be distinguished from the latter by the irregularly triangular lamella antevaginalis rather than those three species; the more triangular, sclerotized sublateral projection of 8th abdominal and a dentate, lateral spur of 7th abdominal segment rather than those three species; and the membranous proximal half of ovoid corpus bursae with dense spinulose rather than those three species. In D. hanoiensis , the lamella antevaginalis irregularly rectangular; the sublateral projection of the 8th abdominal arched with subapical spine and lateral spur of weakly serrated 7th abdominal segment (more rectangular than new species), and the membranous proximal half of ovoid corpus bursae without dense spinulose. In D. simianshana , the lamella antevaginalis triangular; and the globular corpus bursae with ring-shaped signum medially.

Description. Adult ( Figs 2a, 2b ). Length of forewing 6–6.5 mm in males (n=43), 6–7 mm in females (n=11). Head, patagium and tegula deep yellow. Thorax dark brown. Forewing ground color dark brown, with broad, deep yellow costal margin, which inner margin of deep yellow costal margin edged by pale narrow band wholly; with row of small, dark brown dots or patches from basal of costa to tornus; cilia deep yellow. Hindwing ground color pales gray-brown; cilia pale gray-brown. Abdomen brown dorsally and deep yellow ventrally, with deep yellow anal tuft in male and 6th abdominal segment of female with a strongly modified pregenital in female. Male genitalia ( Fig 4 ). Uncus slender, almost 90° bent to inward, with a hook-shaped, small apical spine. Tegumen is weakly sclerotized, triangular in apical half, and roundly broad in basal half. Valva stout, asymmetric, with asymmetrical apical processes: in left valva, rounded apical prominence weakly sclerotized (almost half size of valva), with a straight upper spine (almost same length with apical prominence) stout, blunted and a short (half size of the upper large spine), thin, spine shaped lower process weakly sclerotized; in right valva, an arch-shaped prominence (2x smaller than left valva’s) of upper angle with a stout, weakly bent, blunted spine and stout, short finger-shaped process (about 4x shorter than bent spine) in basal area of the bent spine, and a short, thin lower angle’s process with a slender apical spine, which is almost same length with upper angle’s bent spine; a large, strongly sclerotized basal projections of valva asymmetric, right one more stout apex and weakly curved, apex of both projections covered with small spines. Juxta sclerotized, tubular. Saccus broadly U-shaped. Aedeagus slender strongly bent apically and vesica with one stout, spine-shaped cornutus and one bundle of short spines. Abdomen with median apodeme structure of lyre-like shape on pre-genital tergite ( Fig 8 ) and directed anteriorly as twin thin arms with slightly recurved apices. Female genitalia ( Fig 6 ). Papillae anales are weakly covered with setae. Slender apophysis posterioris about 2 times longer than broader apophysis anterioris. Ostial plate weakly sclerotized, with two slender (2/3 length of sublateral projection of 8th abdominal) apical spines. The lamella antevaginalis irregularly triangular, weakly sclerotized, proximal edge indented. Ductus bursae narrow, tube-shaped, slightly waved, weakly sclerotized whole of length, with short spines in an irregular, elliptical plate in cervix of bursae. Corpus bursae ovoid, membranous, with dense spinulose in proximal half. Abdomen with a modified pouch on the pregenital sternum on each side of the intersgemental membrane ( Fig 9 ).

Etymology. The species is named for the type locality, Nantou County of Central Taiwan,

Figures

FIGURE 9. Female pregenital abdomen of Diduga nantouensis sp. n., showing ventral lateral pouches. 9a. 4–5th abdominal segment (JBH–3940f, Tienchih, Kaohsiung Co., Taiwan). 9b. 1–4th abdominal segment (INU–1912m, Wulai (550m), Taipei Co., Taiwan).

FIGURES 1–2. Adults of genus Diduga spp. from Taiwan. 1a. D. taiwana sp. n., male (holotype, INU–1908Taiwan). 1b. ditto, female (paratype, INU–1907Taiwan). 2a. D. nantouensis sp. n., male (holotype, INU–1910Taiwan). 2b. ditto, female (paratype, INU–1912Taiwan).

FIGURES 3–4. Male genitalia of genus Diduga spp. from Taiwan. 3. D. taiwana sp. n. (holotype, INU–1908Taiwan). 4. D. nantouensis sp. n. (holotype, INU–1910Taiwan).

FIGURES 5–6. Female genitalia of genus Diduga spp. from Taiwan. 5. D. taiwana sp. n. (paratype, INU–1907Taiwan). 6. D. nantouensis sp. n. (paratype, INU–1912Taiwan).

FIGURES 7–8. Male pregenital abdomen of genus Diduga spp. from Taiwan. 7. D. taiwana sp. n. (JBH–3902m, Chingshan, Taichiung Co., Taiwan). 8. D. nantouensis sp. n. (JBH–3901m, Shanpin For. Sta., Kaohsiung Co., Taiwan).