Diarsia zillii, Gyulai & Saldaitis, 2019

Gyulai, Peter & Saldaitis, Aidas, 2019, Notes on the genus Diarsia with the description of seven new species from China (Lepidoptera: Noctuidae), Ecologica Montenegrina 22, pp. 128-151 : 147-148

Diarsia zillii sp. n.

( Figs 31 , 63 )

Type material. Holotype: male ( Fig. 31 ) China, Sichuan, road Yaan / Kangding, Erlang Shan Mt. , H – 2161 m, N29°51’, E102°18’, 12.VI.2009, I.– A. Floriani & Saldaitis leg, slide GYP 2385 (coll. PGM, later to be deposited in the HNHM).

Diagnosis. The new species ( Fig. 31 ) is a specialty, representing a distinct lineage. The male genitalia structure of the new species resembling to some species of the chalcea group, however the vesica structure indicates some affinities to those of the basistriga–cerastioides–tincta species group, particularly to the D. griseithorax . It is remarkably dissimilar in the external features from all the congeneric taxa of the chalcea species group by the greyish ground colour with slight whitish suffusion in the forewings (which is red, reddish brown all but one in the chalcea species group), and more similar to the D. griseithorax ( Fig. 32 ), although the male genitalia structure is apparently matches in most sections with those of the chalcea species group. The separation of the D. zillii from the D. griseithorax is very easy, since the new one is larger (34 mm versus 30 mm), having greyish forewings with whitish suffusion in the basal and medial area and the stigmata are finely whitish outlined; while in the D. griseithorax forewings are more unicolorous, without the whitish suffusion, but with reddish hoe. Additionally, the new species has much darker hindwing. In the male genitalia, the new species ( Fig. 63 ), shows shared features with the D. mandarinella ( Fig. 57 ) and D. dichroa ( Fig. 58 ), indicated particularly by the huge ampulla and high juxta. The best distinctive key features are the somewhat longer, almost evenly slender uncus; much higher, huge juxta, with two asymmetric dorsal extensions; larger, longer, falcate harpe; huge ampulla, distally with rough configuration and the narrower neck of cucullus. The differences are more surprisingly larger in the aedeagus and vesica structure, by the absence of the ventral thorn in the aedeagus and the very different and unique, significantly larger, dorsally also elongate vesica structure, with the asymmetrically huge fields of dense setae and ventrally with an elongate, scythe–like, strongly sclerotized bar. D. zillii conspicuously differs from the externally somewhat similar D. griseithorax ( Fig. 64 ) by the considerably higher, huge juxta, with two asymmetric dorsal extensions; longer, falcate harpe and the absence of clasper; huge ampulla, narrower neck of cucullus, huge, elongate vesica structure, with unevenly situated dorsal fields of dense setae and the presence of the ventral scythe–like, strongly sclerotized bar. Female genitalia is unknown.

Description. A medium sized species, wingspan 34 mm. Antenna of the male is thin, filiform. Ground colour of head and thorax vesture and of the forewings is unicolorous slate grey with whitish suffusion in the basal and medial area in the forewings; only in the subapex visible a diffuse, darkened patch. The wing pattern is also greyish, but well discernible, since the basal–, ante– and postmedial lines are defined with double, dark brown, fine lines; the antemedial line somewhat zigzag, oblique toward the inner costa, the postmedial line arched; the subterminal line almost straight, thin ochre line with slight brown ghost in the inner side. Orbicular and reniform stigmata are light grey, incompletely whitish outlined. Hindwings are unicolorous brown with pale pinkish cilia; discal spot conspicuous, lunular, a dark brown fine arch. Male genitalia. The most typical features of the male clasping apparatus ( Fig. 63 ) are as follows: relatively long, distally slightly tapering uncus; huge juxta, with two dorsal, asymmetric bilateral extensions and deep medial incision between them; large, strong, distally curved ampulla, with rough configuration; long, falcate, distally tapering, apically pointed harpe; ventro–laterally broaden, convex valva with weak “neck” of the large cucullus bearing a streak of strong, long spiculi; slightly curved aedeagus, with longitudinal sclerotized bars distally and ribbon–like, strongly sclerotized, long serrate–dentate bar of the carina extending onto the basal section of vesica; huge, elongate vesica structure, with a large dorsal extended field of dense setae and the presence of a long ventral, scythe–like, strongly sclerotized bar.

Biology and distribution. The new species is known only from the Erlang Shan Mountains at the eastern edge of the Tibetan plateau in the Chinese Sichuan province. Single male was collected at ultraviolet light in mid of June at altitude ranging 2100 m. The new species was collected in virgin mixed forest habitat dominated by various broad–leaved trees such as oaks ( Quercus dentata Thunberg , Quercus glauca Thunberg ), poplars ( Populus cathayana Rehder , Populus simonii Carrière ), elm ( Ulmus parvifolia Jacquin ), rhododendrons ( Rhododendron brachycarpum G. Don , Rhododendron dauricum Linnaeus ), and bamboos ( Phyllostachys ssp., Borinda ssp., Fargesia spp. ).

Etymology. The new species is dedicated in honour to Alberto Zilli, well known noctuidologist, curator of the Noctuidae collection in the Natural History Museum London.

Figures

Figures 25–32. Diarsia spp. adults. 25. D. sciurus sp.n., holotype, male, China, Sichuan(PGM); 26. D. sciurus sp.n., paratype, male, China, Sichuan(AFM); 27. D. sciurus sp. n., paratype, male, China, Sichuan, (PGM); 28. D. sciurus sp.n., paratype, male, China, Sichuan (ASV); 29. D. sciurus sp. n., paratype, female, China, Sichuan (ASV); 30. D. gozmanyi, holotype, male, Vietnam, Fansipan (HNHM); 31. D. zillii sp.n., holotype, male, China, Sichuan (PGM); 32. D. griseithorax, male, Nepal, Kanchenjunga (PGM).

Figures 63-66. Diarsia spp. male genitalia. 63. D. zillii sp.n., holotype, China, Sichuan, GYP 2385 (PGM); 64. D. griseithorax Nepal, Kanchenjunga, slide Hreblay, 12374 (PGM); 65. D. griseocilia sp. n., holotype, China, N Yunnan GYP 4997 (PGM); 66. D. griseocilia sp. n., paratype, China, N Yunnan GYP 4942 (ASV).

Figures 54-58. Diarsia spp. male genitalia. 55. D. reserva sp. n., holotype, China, Yunnan, GYP 5022 (PGM); 56. D. reserva sp. n., paratype, China, Yunnan, GYP 2604 (PGM); 57. D. mandarinella, China, W Sichuan, GYP 4164 (PGM); 58. D. dichroa, China, Yunnan, RL 8935 (PGM).