﻿Taxonomic review of the genus Ammathella Volynkin, 2019 with descriptions of three new species from southeastern Xizang, China (Lepidoptera, Erebidae, Arctiinae, Lithosiini)

﻿Abstract A brief taxonomic review of the lithosiinid genus Ammathella Volynkin, 2019 is presented. Three new species of the genus Ammathella Volynkin, 2019 are described from Motuo County, southeast Xizang: A.longicornuta S.-Y. Huang, Yin & Volynkin, sp. nov., A.lhoba S.-Y. Huang, Yin & Volynkin, sp. nov., and A.monpa S.-Y. Huang, Yin & Volynkin, sp. nov. A key to the species of the genus is provided. Adults and genitalia of both sexes are illustrated.

Ammathella gesar is the only member of the genus currently known to the Chinese fauna, and its type locality is Pailong Village located at the northern slope of the Himalaya in Xizang. However, in the course of identifying the Lithosiini housed in the Tibet Agricultural and Animal Husbandry University, was found a series of specimens of Ammathella from Beibeng and Bononggong (also well-known as 80K) villages in Motuo County, located at the southern slope of the Himalaya. The examination of the male and female genitalia of these individuals revealed that they belong to three species new to science, which are described below. Based on our past studies and new discoveries, the genus is briefly reviewed and a key to the genus is also provided.

Materials and methods
The specimens examined are deposited in the following institutional collections: Tibet Agricultural and Animal Husbandry University (TAAHU), Linzhi, Xizang, China; South China Agricultural University (SCAU), Guangzhou, China, and Museum Witt Munich in the the Bavarian State Collection of Zoology (Museum Witt München / Zoologische Staatssammlung, München, MWM/ZSM), Munich, Germany. The moths were collected at night using light traps. Photographs of the adults of the new species were taken using a Sony DSC-RX100 v1.00 camera, a Canon 5DIII camera, and a Nikon D3100 camera with AF-S Nikkor 18-55 mm lens. The abdomens of the specimens were removed and macerated in 10% NaOH or 8% KOH solution for the examination of genitalia. Photographs of the genitalia of Ammathella gesar were taken under a Keyence VHX-5000 digital microscope. The genitalia of A. longicornuta, A. lhoba, and A. monpa were imaged using a Nikon SMZ18 photograph system, and those of other taxa were taken by a Nikon D3100 camera with AF-S Nikkor 18-55 mm lens attached to a microscope with an LMscope adapter. All pictures were processed using Adobe Photoshop CS5 software. The terminology for adults and genitalia morphology follows Volynkin et al. (2019) and Huang et al. (2020).

Genus Ammathella Volynkin, 2019
Ammatho ( Diagnosis. Externally, species of the genus display a wing pattern typical of members of the Asura/Miltochrista generic complex and consisting of a dull yellowish ground color of the forewing with reddish lengthwise streaks and blackish transverse lines, reminiscent of the genera Sarbine, Processine, Ammatho, and Moorasura Volynkin & Huang, 2019. In male genitalia, Ammathella is characterized by the narrow and elongated valva, the weakly sclerotized medial costal process which is short, swollen and strongly broadened basally, and the small and apically rounded distal costal process. The phallus vesica of Ammathella is rather unique within the genus in bearing a cluster of strong and short cornuti on its ventral side. The female genitalia of Ammathella are characterized by the densely spinulose corpus bursae and the relatively short and sclerotized appendix bursae positioned postero-ventrally and directed posteriorly (Volynkin et al. 2019;Huang et al. 2020).
Description. External morphology of adults. Forewing length 7.5-14 mm in males and 9.5-14 mm in females. Antenna long, weakly ciliate in both sexes. Sexual dimorphism limited: female with broader forewing and paler abdomen. Head and thorax coloration varying from pale orange to reddish-orange, tegula with blackish spot medially. Forewing broad, triangular with rounded apex. Forewing ground color varying from pale orange to orange-red with yellow streaks on veins and yellow irregular spot in discal area; markings dark brown. Costal margin edged with black scales. Basal spot small and round. Antemedial area with dark brown streak on costa (except A. shingwa), in certain species with two spots subbasally. Transverse lines dilated medially and anteriorly. Antemedial line smoothly convex outwards anterio-medially. Medial line sinuous, X-like fused with antemedial line in cell. Medial area between medial and postmedial lines with irregular spot in cell. Postmedial line smoothly convex outwards anteriomedially, in most species touching medial line at costa. Veins in postmedial area with lengthwise dark brown streaks and intense yellow suffusion. Terminal line blackishbrown, thin with short triangular denticles on veins. Cilia blackish-brown. Hindwing ground color pale pinkish-red or ochreous, paler subbasally and deeper or with blackish suffusion subapically. Cilia blackish around apex and pinkish or ochreous, scattered with black medially and at tornus. Abdomen covered with pale pinkish or ochreous hair-like scales, in males, with admixture of blackish scales in distal half or third.
Genitalia. Male. Uncus long and slender, smoothly down curved, distally tapered and apically pointed. Tuba analis moderately broad (ca 1/3 of tegumen length) with thin and weakly sclerotised scaphium and setose subscaphium. Tegumen triangular, moderately sclerotised. Vinculum shorter than tegumen, robust, V-or U-shaped. Valva elongate and relatively narrow. Costa with swollen and apically rounded medial process (vestigial in A. longicornuta sp. nov.) and narrow and apically rounded distal process (broad in A. longicornuta sp. nov.). Membranous lobe of valva large and broad. Sacculus well-sclerotized, dorsally setose in certain species. Distal saccular process short and narrow, rounded or pointed apically, up curved (but directed distally in A. longicornuta sp. nov.). Juxta broad, plate-like with medial membranous commissure, in certain species also with apical process. Phallus moderately broad, tubular, more or less straight or in a somewhat S-like curve. Vesica broad with large sack-like or conical subbasal diverticulum in certain species bearing small cluster of cornuti distally or laterally. Medial diverticulum large, semiglobular, bearing broad cluster of numerous short cornuti. Ventro-lateral medial diverticulum with cluster of small and short cornuti of various sizes and shapes. Ventral diverticulum elongate, covered with numerous small cornuti or spinules. Basal plate of vesica ejaculatorius short and narrow. Female. Papilla analis trapezoid with rounded corners. Apophyses long and thin, more or less equal in length. Ostium broad. Antrum broad and heavily sclerotized, in certain species bearing subostial ligula. Ductus bursae broad and very short, with sclerotized posterior and membranous anterior sections. Corpus bursae large, sack-like, densely covered with numerous spinules medially and posteriorly. Anterior section of corpus bursae densely covered with spinulose scobination, with round or elliptical signum (absent in A. longicornuta sp. nov.). Appendix bursae small, sclerotized, elliptical or conical, positioned postero-ventrally.
Distribution. Species of the genus are known from northeast India, northern Myanmar and southwestern China (Xizang) (Volynkin 2018;Volynkin et al. 2019;Huang et al. 2020).  Diagnosis. Length of forewing 11.4-11.9 mm (n = 5, 11.5 mm in holotype) in males and 12.6-13.1 mm (n = 3) in females. Ammathella longicornuta sp. nov. is externally reminiscent of A. gesar (Figs 11,12,25,26) and A. garo (Figs 13,14,27,33) but is distinguished by the male tip of abdomen, which is pinkish and covered with much lesser blackish hair-like scales than in the similar congeners, and the obsolete submarginal dull yellowish spots on the forewing (whereas they are prominent in A. gesar and A. garo). In the male genitalia, A. longicornuta sp. nov. is distinguished from the two similar congeners by the combination of the following characters. (1) The juxta lacks a medial process, similar to A. gesar, while the juxta of A. garo bears a long conical process. (2) The medial costal process is minute while it is large and prominent in A. gesar and A. garo. (3) The distal costal process is situated more distally than in A. gesar and A. garo, and is much broader and shorter, whereas it is lobe-like and markedly narrower in the congeners.

Species content of the genus Ammathella
(4) The distal saccular process is directed distally whereas it is up curved in A. gesar and A. garo. (5) In the phallus vesica, the subbasal diverticulum bears a small cluster of cornuti apically (absent in A. gesar and A. garo). (6) The semiglobular medial diverticulum bears a broad cluster consisting of several large and long cornuti basally and numerous smaller cornuti ventro-distally, while in A. gesar and A. garo, the cornuti in the semiglobular medial diverticulum are more or less equal in size. (7) The ventro-basal elongate diverticulum of A. longicornuta sp. nov. is longer than in A. garo, while it is absent in A. gesar. Since the female of A. gesar is unknown, the female genitalia of A. longicornuta sp. nov. are compared only to A. garo, from which the new species differs in the shorter and broader ductus bursae, and the lack of a signum bursae, which is present in A. garo.
Etymology. The specific epithet longicornuta refers to the presence of long and large cornuti on the surface of the semiglobular medial diverticulum in vesica of male genitalia.
Distribution. Currently known only from the type locality in Motuo County, southeastern Xizang, China. Diagnosis. Length of forewing 12.2-12.8 mm (n = 3, 12.6 mm in holotype) in males and 13.8-14 mm (n = 2) in females. Externally, Ammathella lhoba sp. nov. is similar to A. gesar (Figs 11,12,25,26) and A. midzhan (Figs 15,16,28,29,34) but is distinguished by the tip of the male abdomen with a markedly sparser admixture of blackish hair-like scales. Additionally, compared to A. midzhan, the new species is significantly larger in size (the forewing length is 12.2-12.8 mm in male and 13.8-14 mm in female vs 7.5-8 and 9.5 mm respectively in A. midzhan). In the male genitalia, A. lhoba sp. nov. is more similar to A. midzhan than to A. gesar by sharing the similar phallus and vesica structure. However, A. lhoba sp. nov. differs from A. midzhan in the combination of the following characters. (1) The medial costal process is slightly shorter and smaller.
(2) The cluster of cornuti on the subbasal diverticulum is larger and bearing granulation basally, while it is smaller and lacks granulation in A. midzhan. (3) The cluster of cornuti on the semiglobular medial diverticulum is larger and the cornuti are smaller and shorter. (4) The ventral medial diverticulum is covered with more cornuti of smaller size while in A. midzhan, while those cornuti are fewer and larger. In the female genitalia, A. lhoba sp. nov. differs from A. midzhan in the anterior section of the corpus bursae densely covered by spinules whereas it is thoroughly membranous in the congener.
Etymology. The specific epithet lhoba refers to the local Lhoba people in Motuo County.
Distribution. Currently known from two localities in Motuo County, southeastern Xizang, China. Diagnosis. Length of forewing 10.6-11.8 mm (n = 4, 10.6 mm in holotype). Ammathella monpa sp. nov. is externally very similar to A. gesar (Figs 11,12,25,26) and a reliable identification requires the examination of the genitalia structures. Compared to another similar species, A. garo (Figs 13,14,27,33), the new species has hindwing cilia black from apex to vein CuA 2 , while it is pinkish, scattered with black, from apex to tornus in A. garo. In the male genitalia, A. monpa sp. nov. is distinguished from the two similar congeners by the combination of the following characters. (1) The juxta is much narrower and smaller. (2) The medial process of juxta is short, round, and covered with spinules thoroughly, whereas the juxta of A. garo bears a long conical medial process, and that of A. gesar lacks a process. (3) The distal costal process is situated more distally from the medial costal process, similar to that in A. garo, while it is situated closer to the medial costal process in A. gesar. (4) The distal costal process is longer than in A. gesar and A. garo. (5) The distal saccular process is apically rounded, similar to A. garo, while it is apically pointed in A. gesar. (6) The phallus is slender and straight, similar to A. gesar, while forms an S-like curve in A. garo. (7) In the phallus vesica of A. monpa sp. nov., the subbasal diverticulum is larger than in A. gesar and A. garo. Additionally, the cornuti on the ventral medial diverticulum of the new species are larger than in A. gesar and more similar to those in A. garo.
The female is unknown. Etymology. The specific epithet monpa refers to the local Monpa people in Motuo County.
Distribution. Currently known only from the type locality in Motuo County, southeastern Xizang, China.  Diagnosis. Length of forewing 11.5-14 mm. Ammathella gesar is externally very similar to A. monpa sp. nov. and A. lhoba sp. nov., and a reliable identification requires the examination of the genitalia structures. Males of A. gesar and A. lhoba sp. nov. can be distinguished from each other by the distal half of the abdomen, which has a markedly denser admixture of blackish scales in A. gesar. The male genitalia of A. gesar are most similar to those of A. monpa sp. nov., but the genital capsule differs in the longer and broader juxta without a medial process, the shorter distal costal process, and the apically pointed distal saccular process (it is distally thicker and apically rounded in A. monpa sp. nov.). Compared to A. monpa sp. nov., the phallus of A. gesar is slightly narrower, the subbasal diverticulum of the vesica is smaller and distally narrower, and the cornuti on the ventral medial diverticulum are markedly smaller.
The female is unknown. Distribution. Known only from the type locality in Linzhi County, southeastern Xizang, China.
Ammathella garo (Volynkin, 2018) Figs 13, 14, 27, 33 Barsine garo Volynkin, 2018, Far Eastern Entomologist 358: 6, figs 3, 4, 22, 34  Diagnosis. The forewing length is 10-10.5 mm in males and 10-11 mm in females. Ammathella garo is externally similar to A. midzhan but differs in the markedly larger size, the more reddish forewing ground color, and the pinkish hindwings. The male genital capsule of A. garo is distinguished from that of A. midzhan by the narrower tuba analis, the presence of a long conical medial process of the juxta, the somewhat smaller medial costal process, the smaller dorsal subapical costal process, and the more robust distal saccular process. The phallus of A. garo is longer (in proportion to the size of the genital capsule) than in A. midzhan. The phallus vesica of A. garo differs from that of A. midzhan in the narrower, conical subbasal diverticulum lacking a cluster of cornuti, and the longer and narrower cornuti of both clusters. In the female genitalia, A. garo differs from A. midzhan in the larger lateral ostial ligula, the narrower and markedly longer antrum, the weaker sclerotized appendix bursae, and the weaker spinulose scobination of the corpus bursae.
Distribution. Known from northeastern India (Meghalaya) (Volynkin 2018 Diagnosis. The forewing length is 11.5 mm in males and 12.5-13.5 mm in females. Ammathella shingwa is externally reminiscent of A. gesar, A. lhoba, and A. monpa but is clearly different by the ochreous abdomen, the markedly narrower reddish pattern elements on the forewing, the thinner postmedial line, and the yellowish hindwing only slightly suffused with pink scales in the submarginal area, whereas in the similar congeners, the abdomen is pinkish with admixture of blackish scales distally, the reddish pattern elements are broad, and the hindwing is pinkish. The male genitalia of A. shingwa are most similar to those of A. midzhan and A. lhoba due to sharing similar short phallus. However, the species can easily be distinguished from A. midzhan and the externally similar congeners by the distally dilated valva with a longer and broader trapezoid basal section of the sacculus and the vesica lacking a medial semiglobular diverticulum with a cluster of cornuti and thoroughly covered with granulation. The female genitalia of A. shingwa differ from those of the congeners in the broader antrum, the broader corpus bursae with a smaller signum, and the larger and more heavily sclerotised appendix bursae. Distribution. Known from northern Myanmar (Kachin State).