Zographetus dzonguensis, Karmakar & Lepcha & Basu & Kunte, 2021

Karmakar, Tarun, Lepcha, Sonam Wangchuk, Basu, Dipendra Nath & Kunte, Krushnamegh, 2021, A new species of Zographetus Watson, 1893 (Lepidoptera: Hesperiidae) from Sikkim, eastern Himalaya, India, Zootaxa 5072 (4), pp. 373-379 : 374-377

Zographetus dzonguensis sp. nov. Kunte, Karmakar & Lepcha

( Figs. 1‒3 )

Holotype ( Fig. 1 ): Voucher code IBC-BM771. ♂. The type locality is Namprikdang village , North Sikkim District, Sikkim, India (27.518403, 88.531640). Approx. 870 m asl. Collected by Sonam Wangchuk Lepcha on 3 Sept. 2021, with permission from the local panchayat (village council) and the Dept. of Forest , Environment and Wildlife Management , Govt. of Sikkim. Preserved dry, pinned, deposited in the Biodiversity Lab Research Collections at NCBS.

Paratypes: Voucher codes IBC-BM770 ( Fig. 1 , adult, pinned and preserved dry; Fig. 2 , genitalia) and IBC-BM772 (preserved in 100% molecular-grade ethanol; Fig. 2 , genitalia) . ♂. Collection data same as the holotype .

Description of the male holotype ( Fig. 1 ): Forewing length: 13 mm. Length of antenna: 8 mm. Head and thorax covered with yellow scales; abdomen ventrally ringed with yellow and black or dark brown, with the tip black. Legs yellow. Antennae black, with a pale midshaft, especially on the underside.

Dorsal side: Forewings dark brown, covered sparsely in ochreous scales. A medium-sized white spot at the lower angle of the cell-end; a larger white spot in CuA1 just below the cell-end spot; and a narrower, more elongated white spot from near the origin of v. CuA 1 in M3. These three spots are adjacent to each other, separated by dark veins. Another smaller white spot in M1. Pale orange-yellow hair tuft along the basal half of the dorsum. Hindwings unmarked.

Ventral side: Forewing dark brown, the basal 2/3 rd of costa and subapical area covered in bright yellow scales. The distal 1/3 rd of costa is narrowly chocolate brown, termen is more broadly bordered chocolate-brown. White spots around the cell similar to dorsal side. Hindwing bright yellow. A large, irregular chocolate-brown spot at cellend. Two smaller chocolate-brown spots in the centre of spaces CuA1 and M3. An even smaller, obscure brown spot at the origin of v. Sc. Wing borders more broadly chocolate-brown at the tornus compared to that on the forewing, tapering towards apex. Cilia paler yellow. The pinned specimen has much of the yellow scales on forewing and those on hindwing costa lost during collection of the specimen.

Description of the paratypes, and intraspecific variation ( Fig. 1 , 3 ): The two paratypes collected, and other specimens photographed in nature, were very similarly patterned to the holotype. The subtle variation was in the form of the size of chocolate-brown spots and borders on the underside: (a) on hindwing, chocolate-brown spots in spaces M3, CuA1 and, when present, in CuA2, being variable in size, (b) the size and shape of the chocolatebrown cell-end spot on hindwing, and (c) variation in the width of the chocolate-brown terminal margin on both the wings.

Male genitalia: Paratypes (IBC-BM770 and IBC-BM772, Fig. 2 ): Tegumen dorso-ventrally broad and dorsal outline almost flat. Uncus long, slender, and the narrow distal tip curved downward. Major sub-uncal processes are absent, which is a characteristic of the genus Zographetus . Saccus is slender in the lateral view, and the rounded tip of saccus is gradually bent upward. Valva undulated along the dorsal margin, ending in a costal process. The costal process is triangular, and the rounded distal tip is produced upward above dorsal margin of corona in the lateral view. Corona is smooth and rounded at the distal and ventral edges, whereas the dorsal margin is serrated with a hump-shaped harpe near the inner margin. Aedeagus consists of a proximal subzonal sheath, which is narrow proximally and broad near the annulus. Subzonal sheath is almost 1.5× longer than the distal suprazonal sheath. Juxta is U-shaped and broad.

Female: Unknown.

Diagnosis: Externally, Z. dzonguensis sp. nov. is very similar to Z. pangi and Z. hainanensis . The main differences are in the shape of the cell spot and spot in M3 on the forewing, and underside colouration of the hindwing. In Z. dzonguensis sp. nov., the spot at the base of space M3 is sharply pointed at the inner edge and conspicuously more elongated compared with Z. pangi and Z. hainanensis . On the forewing of Z. pangi , the spots at cell-end and in CuA1 are larger. On the underside of hindwing, all chocolate-brown spots are larger in both Z. pangi and Z. hainanensis compared with Z. dzonguensis sp. nov.

Zographetus dzonguensis sp. nov. is easily distinguished from the Indian congeners by largely bright yellow wings on the underside, with only narrow chocolate brown borders on both wings. In Z. satwa and Z. ogygia , underside of hindwing is much more heavily marked with chocolate-brown, with purple sheen ( Z. satwa ) or spots ( Z. ogygia ) on the outer half of the wing ( Kunte et al. 2021).

Zographetus dzonguensis sp. nov. is distinguished based on the male genitalia from Z. pangi and Z. hainanensis as follows: in Z. dzonguensis sp. nov., tegumen and uncus are almost equal in length, whereas in Z. pangi and Z. hainanensis uncus is longer than the tegumen ( Fan et al. 2007). The dorsal outline of tegumen is relatively flat in Z. dzonguensis sp. nov., whereas it is prominently more convex in Z. pangi and Z. hainanensis . In the lateral view, vinculum is more acutely curved, and saccus is distinctly bent upward in Z. dzonguensis sp. nov. compared to the other two species.

Absence of sub-uncal processes, and presence of distinct costal process and serrated dorsal margin of corona, are common in all the three species.

The three taxa compared here, Z. dzonguensis sp. nov., Z. pangi and Z. hainanensis , have largely similar colouration, spotting pattern and the male genitalia. However, they are distinguished by subtle and constant differences, similar in degree to the previously described species in this group ( Fan et al. 2007). Unfortunately, these geographically non-overlapping taxa are nowhere common and therefore the collected series are limited, and the comparative molecular data are unavailable. Therefore, it is difficult at present to further comment on their systematic positions at species and subspecies levels. We have not yet been able to generate sufficient molecular data on the three species to resolve these matters, which should be taken up in the future.

Etymology: The new species is named after the type locality of Dzongu in Sikkim. This is a stronghold of the Lepcha—the people of Sikkim —to whom the description of this species is dedicated.

Proposed English name: We propose the English name ‘Chocolate-bordered Flitter’ for this species based on the chocolate-coloured termens of both the wings on the ventral side.

Distribution: The species is known so far only from the type locality of Dzongu in North Sikkim District. We expect it to be more widely distributed in other parts of Sikkim and adjoining Nepal, northern West Bengal, Bhutan, Arunachal Pradesh and south-eastern Tibet, at similar elevations.

Status, habitat, and habits: Based on the current limited experience, the species appears to be very local and seasonal, occurring below 1,000 m asl in mixed evergreen and semi-evergreen broad-leafed forests of North Sikkim District. So far as known, it is active on sunny days from early morning to mid-day. It has largely been observed feeding on bird droppings in shaded stream-beds ( Fig. 3 ).

Flight period: The first sightings of this species were in August 2016. Recent sightings were from the last week of August to mid-September 2020 and 2021. Based on this limited information, the species appears to be univoltine in Sikkim.

Larval host plants and early stages: Unknown. The only known larval host plant recorded for Zographetus in India appears to be Aganope thyrsiflora (Fabaceae) , for Zographetus ogygia ogygia (Hewitson, [1866]) ( Nitin et al. 2018) . Zographetus dzonguensis sp. nov. is expected to feed on related plant genera and species.

Sympatric Zographetus: We have not yet seen any other species of Zographetus at the type locality.

As more information on this species accumulates, it will be made available on the species page of the Butterflies of India website (https://www.ifoundbutterflies.org/zographetus-dzonguensis).

Figures

FIGURE 1. Type specimens of Zographetus dzonguensis sp. nov. A millimetre scale is at the bottom.

FIGURE 2. Male genitalia of paratypes of Zographetus dzonguensis sp. nov. A. lateral view of genital capsule, B. valva, C. aedeagus, D. dorsal view of genital capsule, E. ventral view of genital capsule, F. juxta. In IBC-BM770, ‘A’ shows the outside of the right valve, and ‘B’ shows inside of the left valve (left valve was separated from the genital capsule and then photographed). In IBC-BM772, ‘A’ shows inside of the left valve, and ‘B’ shows outside of the right valve (right valve was separated from the genital capsule and then photographed).

FIGURE 3. Zographetus dzonguensis sp. nov. in life.All individuals were photographed at Namprikdang playground, Dzongu, North Sikkim District, Sikkim, India in August-September 2020 and 2021. Photographs © Sonam Wangchuk Lepcha.