Revision of the family Metarbelidae (Lepidoptera) of the Oriental Region. V. Genus Marcopoloia Yakovlev & Zolotuhin gen. nov. from the Taiwan Island and Indo-Burma biodiversity hotspot

In the fifth part of the revision on the Asian Metarbelidae we describe the new genus Marcopoloia Yakovlev & Zolotuhin, gen. nov. (type species, by original designation: Arbela discipuncta Wileman, 1915). The male and female of Marcopoloia discipuncta (Wileman, 1915) comb. nov. are redescribed; four new species Marcopoloia leloi Yakovlev & Zolotuhin, sp. nov. (type locality: C. Vietnam, Gia Lai Prov., Kon Ka Kinh NP), Marcopoloia nangmai Yakovlev & Zolotuhin, sp. nov. (type locality: Thailand, Changwat Nan, 20 km N of Bo Luang), Marcopoloia siniaevi Yakovlev & Zolotuhin, sp. nov. (type locality: Mynmar (Burma), 40 km N Myitkyina, Chanc Kand village), and Marcopoloia thaica Yakovlev & Zolotuhin, sp. nov. (type locality: Thailand, Changwat Nan, 30 km E of Pua) are described. A new synonym is established: Arbela discipuncta Wileman, 1915, syn. nov. = Arbela baibarana Matsumura, 1927.


Introduction
In the fifth part of our revision on the Oriental Metarbelidae (Yakovlev & Zolotuhin 2020;2021a−c) we examine a complex of specimens with an expressed sexual dimorphism, widely spread in Taiwan and Indochina (Myanmar, Thailand and Laos). Arbela discipuncta Wileman, 1915, was described on a unique female from Kanshirei (currently, Guanziling Hot Spring). It is noteworthy that the author of the first description mistakenly identified the type specimen as "one rather worn male specimen" (Wileman 1915). Matsumura (1927) described Arbela baibarana Matsumura, 1927, on a female from Taiwan (Horisha). Moreover, Matsumura as well as Wileman identified the holotype as a male "one male specimen was collected on the 22nd of April, 1926, by R. SAITO and K. KIKUCHI" (Matsumura 1927). In the modern collections from Taiwan we found females, analogous to the holotypes of Arbela discipuncta and Arbela baibarana together with a small number of males, very different in appearance from the females (the ratio of females and males in the collection MWM = 55:3). Similar males of other species from Myanmar, Thailand and Vietnam were also found in MWM. The description of the new genus and four new species is given below.

Material and methods
The materials for the study were the adult Metarbelidae specimens deposited in various collections: NHMUK -National Museum of Natural History (formerly: The Natural History Museum, London, U.K.); MWM -Museum Witt (Munich, Germany); ZMSU -Zoological Museum of Sapporo University (Sapporo, Japan). The male and female genitalia were mounted in euparal on slides following Lafontaine and Mikkola (1987) and examined with an Olympus SZX16 microscope. The images were taken with the digital camera CMOS 20.7 megapixels and processed using Corel Photo-Paint 2017 software.
Male genitalia. Uncus long, with parallel edges, apically rounded, not extended, with shallow notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, with two harpes on saccular edge; juxta robust with short slightly acute lateral processes; saccus tiny with poorly expressed notch on top; phallus shorter than valve, thin, with very robust semicircular cup-like basal process and small (sometimes, spiky) cornutus.
Female (known only for the type species of the genus) slightly bigger than male, color lighter. Antenna bipectinate, setae shorter than in male. Fore wing brown with rounded discal spot, postdiscally with poorly expressed bands. Hind wing without pattern.

Diagnosis.
The new genus differs from the known genera of Oriental Metarbelidae in the following characters: -the expressed sexual dimorphism (in this characteristic, it is close to Orgyarbela Yakovlev & Zolotuhin, 2020); -the narrow long uncus without expressed extension on top (in this, it is close to Squamura Heylaerts, 1890); -the very extended cup-like basal process on the phallus, which is an apomorphic feature of the new genus.
Composition. The genus includes five species: Marcopoloia discipuncta (Wileman, 1915)  Redescription. Male. Length of fore wing 11.5−13 mm. Antenna bipectinate, setae twice longer than antenna rod diameter. Tip of abdomen with bundle of long modified scales. Fore wing brown, with small black spot in discal cell, poorly expressed pattern of strokes along costal edge, marginal area mottled (darkbrown on veins, ocher between veins), fringe mottled (dark-brown on veins, ocher between veins). Hind wing dark-brown, anal angle brown, fringe ocher.
Male genitalia. Uncus long, with parallel edges, apically rounded, small shallow notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, crescent long harpe in basal third on saccular edge of valve, short thin rod-like harpe on saccular edge in medium third; juxta robust with short slightly acute lateral processes; saccus tiny, with poorly expressed notch on top; phallus shorter than valve, thin, with very wide semicircular cup-like basal process; spiky cornutus in vesica.
Female. Length of fore wing 14−15 mm. Antenna bipectinate, setae shorter than in male. Fore wing from brown to ocher, with round discal spot, poorly expressed bands postdiscally. Hind wing brown, without pattern, fringe ocher.
Female genitaliasee generic description.

Diagnosis.
Most close to M. leloi, from which it differs in the poorly modified, small harpes and poorly expressed pattern on the fore wing.

Distribution. Taiwan. Probably distributed in the South-Eastern China (Fujian Province) and Southern
Korea (Huang et al. 1990;Park et al. 2006). Huang et al. (1990) writes "the metarbelid Arbela baibarana [Squamura discipuncta] infesting Casuarina trees", using data on the Fujian Province in China. The discovery of the female of Metarbelidae "Squamura sp." in South Korea (Daecheong Island) (Park et al. 2006) was very interesting. Probably, both reports (judging by the distribution) refer exactly to M. discipuncta (Wileman, 1915), but the finds confirmed by the factual material and photos, according to GBIF (Lin 2021;Lin & Shih 2021), are only from Taiwan. Description. Male. Length of fore wing 10 mm. Antenna bipectinate, setae twice longer than antenna rod diameter. Tip of abdomen with bundle of long modified scales. Fore wing brown, with small black spot in discal cell, small black spots along costal and hing edge of wing, marginal area ocher, fringe mottled (darkbrown on veins, ocher between veins). Hind wing dark-brown, anal angle brown, marginal area ocher, fringe ocher, base of fringe brown. Male genitalia. Uncus long, with parallel edges, apically rounded, slightly extended, small semicircular notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, with long finger-like harpe on saccular edge in basal third and shorter finger-like harpe on saccular edge in medium third; juxta robust, with short, slightly acute lateral processes; saccus tiny with poorly expressed notch on top; phallus shorter than valve, thin, with very wide semicircular cup-like basal process, vesica with spiky cornutus.
Diagnosis. Most close to M. discipuncta, from which it differs in the bigger finger-like harpes and the mottled pattern on the fore wing.

Distribution. Central Vietnam.
Etymology. The new species is named after Lê Lợi (1384-1433), a Vietnamese rebel leader who founded the Later Lê dynasty and became the first emperor of the restored kingdom of Đại Việt after it had been conquered by the Ming dynasty. Description. Male. Length of fore wing 12.5 mm. Antenna bipectinate, setae twice longer than antenna rod diameter. Tip of abdomen with bundle of long modified scales. Fore wing dark-brown, with poorly expressed brown portions discally and postdiscally, marginal area and fringe mottled (dark-brown on veins, ocher between veins). Hind wing dark-brown, anal angle brown, marginal area and fringe mottled (darkbrown on veins, ocher between veins). Male genitalia. Uncus long, with parallel edges, apically rounded, with long triangular notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, thick curved harpe with mastoid apex in basal third of saccular edge, small mastoid harpe in medium third of saccular edge; juxta robust, with short, slightly acute lateral processes; saccus tiny, with poorly expressed notch on top; phallus shorter than valve, thin, with very wide semicircular cup-like basal process, strongly curved in medium third, with long rod-like cornutus.

Diagnosis.
Clearly differs from other species of the genus in the long triangular notch on the top of the uncus, the poorly expressed harpes and the phallus strongly curved in medium third.

Distribution. Northern Thailand.
Etymology. The new species is named after the Nang Maifemale fairies of Thai mythology. Description. Male. Length of fore wing 13.5 mm. Antenna bipectinate, setae twice longer than antenna rod diameter. Tip of abdomen with bundle of long modified scales. Fore wing brown, with poorly expressed dark-brown pattern, marginal area ocher, fringe mottled (dark-brown on veins, ocher between veins). Hind wing dark-brown, anal angle brown, marginal area and fringe mottled (dark-brown on veins, ocher between veins). Male genitalia. Uncus long, with parallel edges, apically rounded, slightly extended, shallow semicircular notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, with thick semicircular harpe in basal third of saccular edge and small semicircular harpe in medium third; juxta robust, with short, slightly acute lateral processes; saccus tiny, with poorly expressed notch on top; phallus shorter than valve, thin, with very wide semicircular cup-like basal process, slightly curved in medium third, rod-like cornutus in vesica.

Diagnosis.
The new species differs from the known species of the genus in the mottled pattern on the fore wing and in the thick semicircular harpe in the basal third of the valve. Description. Male. Length of fore wing 11 mm. Antenna bipectinate, setae twice longer than antenna rod diameter. Tip of abdomen with bundle of long modified scales. Fore wing light-brown, with poorly expressed dark-brown pattern of strokes and blurred bands throughout all wing, marginal area and fringe mottled (dark-brown on veins, ocher between veins). Hind wing dark-brown, marginal area and fringe ocher. Male genitalia. Uncus long, with parallel edges, apically rounded, slightly extended, with shallow semicircular notch on top; subscaphium long, funnel-like; gnathos arms thin, gnathos poorly expressed; valve short, rounded, with long finger-like harpe in basal third of saccular edge and shorter finger-like harpe in medium third; juxta robust, with short slightly acute lateral processes; saccus tiny, with poorly expressed notch on top; phallus shorter than valve, thin, with very wide semicircular cup-like basal process, spiky cornutus in vesica.
Female unknown.

Diagnosis.
In the genital structure, the species is close to M. nangmai, from which it differs in the contrast light-brown fore wing. In the male genitalia, the uncus is significantly thicker than in M. nangmai.