Amathusia travancorica Kunte, 2024

Kunte, Krushnamegh & Basu, Dipendra Nath, 2024, Two new taxa of brush-footed butterflies (Lepidoptera: Nymphalidae) from the Western Ghats biodiversity hotspot, southern India, Zootaxa 5543 (3), pp. 343-367 : 346-355

Amathusia travancorica Kunte sp. nov.

Holotype ( Fig. 1 ): Voucher code IBC-PW981 . ♂. Thenmala FRH , near Shendurney WLS , Kollam District, Kerala, India (lat-long: 8.9594 N, 77.0626 E). Approx. 90 m asl. Raised from caterpillar on a Licuala palm ( Arecaceae ) on 2012/12/19, eclosed and preserved on 2013/01/14. Collected by Krushnamegh Kunte. Preserved dry, pinned, with thoracic muscle tissue and two legs (mid- and hind-leg on the right side) preserved in 100% molecular-grade ethanol. Deposited in the Biodiversity Lab Research Collections at NCBS.

Description ( Fig. 1 ):

Forewing length: 50 mm. Length of antenna: 22 mm. Head brown above; palps white; eyes pale brown with vertical dark bands (eyes turn dark brown upon preservation). Antennae pale reddish-brown. Proboscis brown. Thorax and abdomen brown above, white on thorax and pale yellow on abdomen below. Abdomen with tufts of long, dense scales on the side, which are longest (7-8 mm) on segments 9–12, almost black above, yellow below. Legs pale brown.

Wings broad. Forewing termen straight, not concave; dorsum straight. Hindwing very broad and rounded except the tornus, which is produced into a lobe. Three tufts of long, black scent scales: (a) along v1b, (b) in an adjoining fold in interspace 1c, and (c) between v7 and v8.

Dorsal side: Forewings pale rusty-brown, without markings, but markings from the ventral side are visible faintly through the wings; i.e., markings from the ventral side may show through on the dorsal side. Hindwings pale rusty-brown, same as the forewing; dorsum area that covers the abdomen is white. Tornal lobe with two small, white-bordered black spots on either side.

Ventral side: pale yellowish-brown with dark brown and white bands spanning across forewing and hindwing, similar to other members of the genus: three dark bands at the wing bases and in the discal cell, alternating with white bands; a pale broad band just beyond the discal cells; a white-bordered dark brown, broad band from FW costa to the large post-discal eyespot on HW (this band is the darkest), followed by a very broad pale brown band and a paler yellowish-brown submarginal band. The terminal margin is dark brown with a pale line on it. There are two large eyespots, one in interspace 2, and the other in interspace 6. Tornal lobe has two small, white-bordered black spots on either side, similar to the upper side.

Paratypes, and intraspecific variation ( Fig. 1–3 )

♂: voucher code IBC- PW982 . Forewing length: 49 mm. Length of antenna: 21 mm.

♀: voucher code IBC-PS668 . Forewing length: 50 mm. Length of antenna: 22 mm. Although the designation of allotype is not regulated but it is allowed by ICZN Rules, this paratype may be considered an allotype of the species.

♀: voucher code IBC-PW976 . Forewing length: 49 mm. Length of antenna: 22 mm.

Collection and preservation protocols, collection locality and other details same as the holotype, except that: (a) IBC- PW982 caterpillar collected on 2012/12/18, and mid- and hind-leg on the left side of the adult preserved in ethanol, (b) IBC-PS668 eclosed on 2013/01/17, and both pairs of mid- and hindlegs preserved in ethanol, and (c) IBC-PW976 both mid-legs and left hindleg preserved in ethanol.

The male paratype (IBC- PW982) is very similar to the holotype, with no significant differences in morphology or markings. Both female paratypes have ventral sides similar to the holotype but their discal bands are much darker chocolate-brown. Their dorsal sides are similar to each other, but differ from that of males as follows: (a) Bands from ventral side appear on the dorsal side more prominently, (b) there is a broad, diffused yellow patch from costa till interspace 4, which is separated by a dark brown band from another narrow, yellow submarginal band that spans from interspaces 1b to 5.

Apart from these sexually dimorphic differences, all the types differ to a very small degree from each other, presenting a uniform phenotype in the Western Ghats. Seasonal variation, if any occurs, has not yet been recorded.

Genitalia: Male (IBC-PW982, Fig. 2a–e ): Tips of the uncus relatively slender, long, diverging at a small angle but their two sides are deeply cleft up to the base, and the tip is strongly arched near the joint with tegumen. In lateral view, valve broad, gently sloping, ending in a narrow point, with long hair at the lower margin. Phallus (aedeagus) long, narrow, prominently curving upward for the distal 1/3 length.

Diagnosis ( Fig. 3–4 ): Amathusia travancorica sp. nov. has a distinctive phenotype compared to all other SE Asian and Andamanese Amathusia . A combination of four main characters readily and consistently differentiates A. travancorica sp. nov. from related taxa ( Fig. 4 , in which numbered pointers correspond to the following numbered characters): (1) FW termen straight in both sexes, not concave (prominently concave in A. friderici , A. phidippus and all other SE Asian species, especially in P. masina ); (2) HW termen conspicuously more convex, and not prominently produced leading up to the tornal lobe (HW termen straighter and tornus prominently elongated and produced in A. friderici , A. phidippus , A. masina and A. perakana ); (3) In male, UPF is uniform pale rusty-brown, without any yellow markings (very prominent yellow subapical band almost joining the submarginal yellow band in A. friderici , A. binghami and A. schoenbergi ; pale submarginal band showing through more prominently in A. phidippus ), and (4) In female, UPF yellow markings are more faint and diffused (yellow markings very prominent and more clearly delineated in A. friderici and A. phidippus ).

Additional diagnostic characters of A. travancorica sp. nov. are: (a) UNH has two large eyespots (two large spots and a smaller spot in between the two large spots in A. andamanensis ), (b) UNF outer edge of the large dark discal band smooth (conspicuously jagged in A. ochraceofusca and A. schoenbergi ).

The male genitalia of A. travancorica sp. nov. may be distinguished from all other Indo-Malayan Amathusia by their slender, long tips of the uncus, which diverge from each other at a small angle but they are deeply cleft up to the base ( Fig. 2e ). In contrast, uncus tips of other Amathusia diverge from each other at a much greater angle and therefore their tips are widely separated; those in andamanensis are relatively broader and shorter, those in friderici and masina are bent outward at the tip and more widely separated at the base, and those in phidippus are not deeply cleft up to the base ( Fig. 2f ) ( Aoki et al. 1982; Corbet et al. 2020; Eliot 1964; Uémura 1986). Additionally, the long, narrow phallus in A. travancorica sp. nov. is prominently curved upward for the distal 1/3 length, whereas phallus in A. phidippus and schoenbergi is nearly straight and curved upward gently only for the distal 1/4 length, that in binghami , ochraceofusca and perakana prominently bent upward at half length (it is also much more robust in perakana ), and the tip is much broader in masina ( Aoki et al. 1982) .

Several authors have earlier described the placement and colour of hair-pencils at v1b, interspace 1c, and between v7 and v8 among Amathusia species, in addition to the hair pencils on the side of abdomen ( Eliot 1964). We have observed that the size and colour of these hair-pencils are variable among individuals within each species. Younger individuals have larger hair-pencils, and older individuals have much smaller hair-pencils, sometimes having lost all the long scales. The colour is usually variable, ranging from pale brown to black. All these variations have been observed among individuals of A. travancorica sp. nov., including the type specimens described above. If there are consistent species-level differences among Amathusia species, then they need to be characterized carefully and reliably before they may be used as diagnostic, especially between A. travancorica sp. nov., A. friderici and A. phidippus . In museum specimens these hair-pencils are often damaged during pinning, or those inside wing folds are difficult to evert, as also observed earlier by Eliot (1964).

Etymology

Scientific name: We name Amathusia travancorica sp. nov. after its endemic distributional range in the southern Travancore region of Kerala.

English name: We propose the English name ‘Travancore Palmking’ for Amathusia travancorica sp. nov. based on its endemism to the southern Travancore region.

Historical Records: Marshall and de Nicéville (1882), Moore (1896), Talbot (1947), and d’Abrera (1985) did not mention the Western Ghats populations of Amathusia . Evans (1932) listed A. phidippus friderici in “S. India ”, and Wynter-Blyth (1957) as A. phidippus in “Travancore”, but neither mentioned specific locations. These two mentions appear to be based on three specimens collected from near Thiruvananthapuram, presumably in the 1920s, but we have been unable to locate these specimens (they may have been destroyed in an unknown museum in the Thiruvananthapuram area). NHMUK has a single female from Kottayam, Kerala, collected in 1952, but this location is apparently not published in scientific literature (see further details in Materials and Methods). More recently, C. Susanth, B. V. Premkrishnan and R. Murukesh recorded two individuals, one each from Palode (a small village situated 35 km from Thiruvananthapuram) and Kattilappara, Shendurney WLS (https://web.archive.org/ web/20080213063439/http://susanthsbirdsandbutterflies.blog.com/1770510/), in 2000/07 and 2002/05. Mathew and Pulikkal described the early stages and a small population of A. phidippus from Thenmala ( Mathew & Pulikkal 2009). Likewise, Bhakare and Ogale specify the occurrence of A. phidippus friderici in “Southern Western Ghats” ( Bhakare & Ogale 2018). There are no specimens in the McGuire Centre for Lepidoptera and Biodiversity, MCZ, or the Smithsonian National Museum of Natural History.

Species Biology and other Notes

Distribution: Although the species has been reported broadly from “S. India ” and “Travancore”, the species is not at all widespread. Only four confirmed locations are known ( Fig. 6 ): Thenmala (type locality) and Kattilappara (both in Shendurney WLS), Palode (Nedumangad Taluk, Thiruvananthapuram District) and Kottayam (Kottayam District, the Sharman location; see Materials and Methods). All four locations are in Kerala. This narrows the distributional range to southern Travancore, although the species may likely be found in other low-lying evergreen forest patches of Travancore in southern Kerala. In any case, the species appears to be endemic to Kerala.

Status, habitat, and habits: Amathusia travancorica sp. nov. has been described as ‘Very rare’ ( Wynter-Blyth 1957) and ‘Rare’ ( Evans 1932). All the above historical records appear to be based on less than a dozen sightings in nature and fewer specimens than that ever collected and deposited in research collections. Thus, the species appears to be truly very rare. Published sightings were from densely shaded parts of low-lying evergreen forests, sometimes at forest edges. All the known sightings are below 500 m asl. Hence, the species appears to be a forest specialist, with a high conservation value due to its narrow distribution and rarity ( Kunte 2008).

Known habits of Amathusia are based largely on descriptions of A. phidippus in SE Asia, although in historical literature they have been loosely applied to the Western Ghats populations as well, and these agree closely with our own observations in the field. The species is known to be strictly crepuscular, spending the day resting in shaded areas. If disturbed during this time, the butterflies fly only a short distance and settle again, often in more shaded and inaccessible areas. Around sunset they start flying in relatively open areas under closed or partial forest canopy, often flying along the same routes for hours. They may venture in coconut plantations near forests in search of mates and larval host plants (palms; see below). They normally fly relatively slowly and in a bobbing manner to dodge obstructing dense vegetation among which they fly. However, they are capable of flying rapidly if disturbed and efficiently navigate dense vegetation owing to their broad wings, slight flicks of which can help butterflies change course. They settle down to feed on fermenting fruits, tree sap, and droppings of mammalian carnivores as well as herbivores. Similar to other Amathusiini , they have not been observed feeding on flower nectar. They come to light rarely. One individual recorded by Susanth and team had come to a veranda light in a forest guest house after the rains, and the second—a female—was fluttering by a rattan straggler apparently to lay eggs.

Flight period: Sightings of A. travancorica sp. nov. have been infrequent and sporadic. Hence, its flight period and voltinism are poorly understood, although it is expected to be multi-voltine.

Larval host plants and early stages: Cocos nucifera and Licuala ( Arecaceae ) are commonly recorded as larval host plants of A. travancorica sp. nov., along with Calamus thwaitesii that is recorded less frequently ( Nitin et al. 2018). Susanth et al. (on the blog post cited above) suggest that the species may feed on rattan palms in dense forests. It is possible that the species feeds on almost any available palm in its habitat. Leaves of the exotic, ornamental palm Dypsis lutescens were readily accepted by caterpillars, on which the lifecycle was completed in captivity ( Mathew & Pulikkal 2009). The early stages are documented in detail ( Mathew & Pulikkal 2009), and also illustrated here with additional images showing close-ups of caterpillar head and different views of the pupa that have not been illustrated in previous literature ( Fig. 5 ).

Sympatric Amathusia : No other Amathusia occurs in the Western Ghats. The only other Indian species, Amathusia andamanensis Fruhstorfer, 1899 , is endemic to the Andaman Islands ( d’Abrera 1985; Evans 1932; Talbot 1947).

Further information will be made available on the species page of the Butterflies of India website (https://www. ifoundbutterflies.org/ Amathusia ) as additional observations accumulate.

Figures

FIGURE 1. Type specimens of Amathusia travancorica sp. nov. A millimetre scale is at the bottom. Photographs: Dipendra Nath Basu and Krushnamegh Kunte.

FIGURE 2. Male genitalia of Amathusia travancorica sp. nov. (paratype, IBC-PW982). a: lateral view of genital capsule or armature showing the inside of the left valve (right valve removed), b: dorsal view of genital capsule, c: outside of the right valve, d: Phallus (aedeagus), e: dorsal view of the tip of uncus, along with its shape tracing, and f: shape tracings of dorsal view of other Indo-Malayan Amathusia. Photographs: Dipendra Nath Basu and Ujwala Pawar. Genitalia tracings are redrawn from Uémura (1986), except that of A. travancorica sp. nov. (this study).

FIGURE 3. Comparison of Amathusia travancorica sp. nov. with other similar Amathusia (see Materials and Methods for specimen details). A millimetre scale is at the bottom. Photographs: Krushnamegh Kunte and Gaurav Agavekar.

FIGURE 4. Diagnostic characters of Amathusia travancorica sp. nov., marked on digitally enhanced images from which wing-wear has been removed to illustrate the distinctive phenotype of the species. The new species is compared with two species whose names have been applied to the Western Ghats populations in the past. Numbers point to distinctive characters: 1: forewing termen, 2: hindwing termen and tornus area, 3: yellow markings on forewing of male, 4: yellow markings on forewing of female (further details in the text). Images are not to scale. Photographs: Krushnamegh Kunte, Dipendra Nath Basu and Gaurav Agavekar.

FIGURE 5. Early stages of Amathusia travancorica sp. nov. a–h: 5th instar caterpillar. 2012/12/23 (a, b: lateral view; d, h: dorsal view; c (frontal) and e (lateral) close-up of the head; f: close-up of abdominal proleg; g: close-up of processes at the tip of the abdomen); i–l: pupa. 2013/01/15 (i: ventral view; j: dorsal view; k: close-up of the head and thorax in dorsal view; l: lateral view); m–o: pupa just before eclosion (2013/01/17); p: eclosed female resting on the pupal case (2013/01/17). Thenmala FRH, Shendurney WLS, Kerala. Photographs: Krushnamegh Kunte.

FIGURE 6. Distributional range map of Amathusia travancorica sp. nov. Map: Krushnamegh Kunte.