Aenetus simonseni Beaver & Moore, 2020

Beaver, Ethan P., Moore, Michael D., Grehan, John R., Velasco-Castrillón, Alejandro & Stevens, Mark I., 2020, Four new species of Splendid Ghost Moths (Lepidoptera: Hepialidae:) from Australia and Papua New Guinea, Zootaxa 4809 (3), pp. 449-474 : 452-455

Aenetus simonseni Beaver & Moore , sp. nov.

( Figs 1–2 , 7 , 9–11, 18, 21 , 24–26 , 59–61 )

Type specimens: Holotype ♂, ANIC . Paratypes, 10 ♂, 8 ♀, SAMA, ANIC, MAGNT, DALC, UQIC, AKC .

Type locality: East Point, near Darwin, Northern Territory, Australia.

Etymology. This species is named in honour of Danish entomologist Dr Thomas J. Simonsen, in recognition of his recent work on the Australian Hepialidae . A noun in the genitive case.

Type material. HOLOTYPE, (in ANIC) ♂ East Point , Northern Territory, Australia, 03 December 2018, 12°24’26.4”S 130°49’27.4”E, coll. N. Volpe / Spec. No. 19030 leg removed for tissue storage MD Moore / Dissection no. EPB-010 / ANIC 31-071235 .

PARATYPES: 18 in total. 3 ♀, 1 ♂ ( ANIC) : 1 ♀, Rimbija Island , Wessel Islands, NT, 11.01S 136.45E, 17 Janu- ary 1977, E. D. Edwards / Dissection no. EPB-ANIC-18 / ANIC 31-071236 . 1 ♂ with the same data except the date 11 January 1977 / dissection no. EPB-ANIC-022 / ANIC 31-071237 . 1 ♀ [very poor condition, extreme scale loss] Black Point , Cobourg Peninsula, NT, 11.09S 132.09E, 30 Jan 1977 E.D. Edwards / Dissection ID. EBB-ANIC-5 / ANIC 31-071238 . 1 ♀ Howard Springs, NT, 10 Nov 1972, I.F.B Common / Genitalia slide H873 / ANIC 31 -

071239. 1 ♂ ( SAMA) : ♂ Groote Island , Northern Territory, November 1921, coll. N. B. Tindale / E. S. Nielsen gen slide no. 2405 / SAMA Database No. 31-016391 . 1 ♂ Holmes Jungle , 8 ml. NE of Darwin, NT, 130°56E, 12°24S, 6 December 1972, T . Weir, / 2152 ( MAGNT) . 1 ♂ 3 ♀ ( UQIC): Darwin , NT, E.J. Dumigan, 03-07 February 1964 . 2 ♂, 1 ♀ ( DALC) : 1♂ East Point, Darwin , NT bred/larva, 25 November 2002, D. A. Lane, / LM-112 / Leg Taken MD Moore spec. no. 19321. A further 1 ♂, same data except 29 December 2002 . 1 ♀ Darwin , NT, 21 February 1964, E.J. Dumigan. ( MV) ; 1 ♂ Batchelor , NT, G.F. Hill / T-22494 . 1 ♂ P. Darwin , NT, Oct 1908, F.P. Dodd / T-22493 . 3 ♂ ( AKC) ; 1 ♂ Kakadu NP, Noorlangi Rock , NT, 12°51’37”S 132°49’07”E, larva: 30 March 2009, e.l. 1-15. Dec. 2009, leg. A. Kallies / 398 / MDM specimen number 20022. 1 ♂, same data except 399, MDM specimen number 20023. 1 ♀ same data except 400, MDM specimen number 20024.

Distribution. Aenetus simonseni sp. nov. is widely distributed over the coastal higher-rainfall areas of the Top- End of the Northern Territory ( Fig. 56 ).

Diagnosis. This is the only Aenetus species and the only member of the Hepialidae known from Top-End NT. Males of A. simonseni sp. nov. can be distinguished from A. thermistis ( Figs 3–4 , 8 , 12–14, 19, 22 , 27–29 ) of eastern Queensland by the blue or blue-white hindwings in contrast to broad swathes of pink along the costal, tornal and inner margin of the hindwing (not so obvious in faded or old specimens). The forewings are generally more aqua-green than A. thermistis but this is subject to variation. In the forewing, the anterior edge of the medial line is whiter and posterior edge a darker more defined green. The valvae of the male genitalia are proportionately larger and the apical, medial and basal hooks are more evenly spaced, with the apex flattened. A thickened portion of the sacculus is nearly confluent with the basal hook, while in A. thermistis this is represented only as a small knob. There are also differences in general proportions and shape of the vinculum, where the lateral margin is more incurved and posterior projections shorter. The intermediate plate has 2-3 deep grooves on the dorsal edge while it is smooth in A. thermistis . Pseudoteguminal twin processes are shorter, projected farther back on the basal rim. The disto-posterior margin of the pseudotegumen is broader, and rounder. Sternite 8 in A. simonseni sp. nov. is almost twice the size of that of A. thermistis , and with the sclerotised region more extensive, posterior projection shorter and flanked by a small dentation before the postero-lateral corners, which are pointed in this species but rounded in A. thermistis . Females are also externally similar to A. thermistis , however, A. simonseni sp. nov. has more numerous brown scales on the legs, while the wings are generally ‘cleaner’ and the spots in the centre of the medial area are smaller—however these are features subject to variation and the most reliable method is dissection of the genitalia, where the antevaginal lamella differ significantly particularly in the medial area with three indentations on the posterior margin, whereas there are only two in A. thermistis , which has the apex flattened. Lateral lobes are smooth, while in A. thermistis they have two indentations. The bursa copulatrix is distinct, with the diverticulum comparatively shorter than in A. thermistis , and the apex of the corpus bursae, though broad, is less round than in A. thermistis . Aenetus simonseni sp. nov. can be distinguished from Aenetus nr. tegulatus as examined from Indonesia and the Torres Strait, Qld (sensu Grehan et al. 2018; see methods) by female genitalia, where in A. nr. tegulatus the medial area of the antevaginal lamella is broad and with two indentations, closer to that of A. thermistis , and the bursa copulatrix is distinct, with the diverticulum narrower, pointed at the apex and closer to equal in length to the corpus bursae, which is further rounded at the apex. Males of A. simonseni sp. nov. are somewhat similar to A. eximia (Scott) but are distinguished by eighth sternite shape, which is smooth-sided and not anteriorly dentate, and by general proportions and shape of the valva, in which A. eximia has the medial hook longer. The two species also differ by the presence of brown scales on the legs and FW costa of A. simonseni sp. nov.. Aenetus sumatraensis Grehan, Witt & Ignatev, 2018 and A. nr. tegulatus lack scales on the dorsal surface of the antenna, present in both sexes of A. simonseni sp. nov. and A. thermistis . Differences between A. simonseni sp. nov. and A. maiasinus sp. nov. are covered under that species.

Description. Male ( Figs 1–2 ). Forewing length: 32–36 mm, hindwing 29–32 mm, expanse: 71–76 mm (n = 7). Head: Antennae as long as head and slender, filiform, pale brown, covered with fine sensilla chaetica, short flattened scales from pedicel to mid flagellum, scape rectangular, pedicel globular, 31 flagellomeres. Eyes prominent, larger than head capsule, larger than in female, almost meeting dorsally. Scales on frons and vertex dense and dark green. Labial palp three segmented, palpomeres rectangular, middle longest, apical shortest.

Thorax: Pro and mesothorax dorsally and ventrally covered in fine pale green to blueish-green scales and interspersed with pink scales on ventral surface. Legs dark green with brown scales at proximal end of femur, tibia and tarsi, epiphysis sub-triangular, less than ¼ length of tibia; hind leg with ochreous metatibial tuft of long androconial scales. Arolium rounded.

Wings: Forewing: broad and triangular. Costa slightly concave centrally and convex towards apex. Apex point- ed, wing margin slightly concave toward apex, rounded with gently curved tornus. Wing venation classically hepialine ( Dumbleton 1966). Hindwing: broad, triangular with pointed apex, tornus rounded. Dorsal forewing ground colour light green or aqua-green with an uneven transverse band along medial line from costa to tornus, between inner margin at Rs2 and A1. Basal-side of line white, proximal dark green lowlights between veins Rs2 and CuA2. Faint mottled patterns of alternating lighter and darker green across wing surface, extensive near outer wing margin. Scales fading from light green to aqua-green towards tornus, light pink piliform scales around jugum. Costa light green with five dark brown bars, final bar distal to medial line. Ventral surface ground color pink with pink-ochreous piliform scales centrally and basally. Patch of green scales present at outer margin between Rs4 and M3. Entire surface with lustrous iridescent shine not present on dorsal. Hindwing dorsal surface blueish-white to white, pale blue in fresh specimens, costa and anterior margin marked a mottled green. Fringe dark green. Tornus mottled green; inner margin with pink piliform scales anteriorly. Apex acutely pointed. Posterior discal cell narrowly triangular, narrowing towards base, final discal cell rounded. Basal area covered with white or blue piliform scales. Ventral surface with costa and medial area yellowish-green fading to blue towards tornus, tornus and inner margin pink and clothed with pink piliform scales into basal area. Apex pink-tipped.

Abdomen: Long, narrow, basally covered in red-pink scales, sometimes white, green at apex. Sternite eight ( Fig 21 ) rectangular, anterior corners rounded, posterior margin heavily sclerotized, with short central tooth, very short and weakly sclerotised projections midway between posterior corners and central tooth.

Genitalia ( Figs 9–11 ): Apodemal vinculum broad, wider than high in posteroventral view, lateral margin incurved sharply, with paired posterior projections sub-rounded and smooth. Saccus sub-triangular, broad, flattened distally. Intermediate plate ovoid, with three deep grooves ventrally. Basal rim of pseudotegumen narrow, sub-triangular with ‘m’ shaped lateral ridge, dorso- and distoposterior margins of pseudotegumen smooth, rounded and lightly sclerotized. Twin processes greatly reduced, broad, triangular, pitched back towards intermediate plate. Ventral pseudoteguminal arm present, narrow and pointed, becoming membranous. Valvae ( Fig. 18 ) large, softly sclerotized, with three large spines, heavier sclerotisation on spines, valva narrower at proximal end, with sub-square sacculus. Viewed posteroventrally, valvae curve away from pseudotegumen. Tip of valva ends as spine tapering to sharp point, oriented vertically away from abdomen. In lateral view ( Fig. 11 ) this spine is positioned at near right angle, with tip straight. Largest spine from middle of valva, curved, tip pointing anteriorly, inner edge with small bump. Third spine shortest, curved almost confluent with sacculus margin. Long, fine setae on tip of dorsal surface, shorter setae present between spines and along inner lateral margin. Juxta broad, flattened and U-shaped. Trulleum membranous.

Variation. Exact position and shape of medial line on forewing, extent of pink scales on anterior half of abdomen, extent of brown scales on forelegs as well as the width of the brown spots along costa is variable. General ground colour ranges from grass green to greyish blue, with living specimens often appearing brighter than museum specimens where fading may occur..

Female. ( Fig. 7 ) Forewing length: 31–42 mm, hindwing: 28–33 mm, expanse: 72–84 mm (n = 7). Head: Antennae slightly longer than head to mesothorax, slender, filiform, pale brown, dorsally scaled to middle, scape rectangular, pedicel globular, 28 flagellomeres. Eyes prominent, of roughly same height as head capsule, wider set than in male. Scales on frons and vertex dense and light green, obscuring base of antenna. Labial palps three segmented, basal two palpomeres rectangular, apical rounded, middle longest, apical palpomere shortest.

Thorax: Pro- and mesothorax dorsally and ventrally covered in fine light green scales. Patch of dark grey to brown scales at base of wing. Fore and mid legs covered with dense light green scales, grey to dark brown on tarsus and anterior apex of tibia. Hind legs light brown, reduced. Foretibia with narrow, triangular epiphysis. Arolium rounded.

Wings: Forewing: broad and triangular. Costa slightly concave centrally and convex towards apex. Wing venation classically hepialine. Hindwing: broad, subtriangular, tornus rounded. Dorsal forewing ground colour light green with darker green mottled pattern consisting of darker green lines of irregular length and angle on all areas of wing surface between Rs1 and 2A. Two to three cinnamon brown to dark grey spots in centre of wing along medial line between Rs4 and M3, a smaller spot between CuA2 and 1A along the same line, and sometimes at end of CuP distal to discal cell. Margins with small cinnamon or dark grey spots between Rs1 and CuA2, fringe dark brown, light grey-brown at tornus, irregular cinnamon streak between CuA2 and jugum. Costa green with up to 10 cinnamon brown to dark grey spots from discal to medial area, fading to green at apex. Ventral surface cinnamon pink, costa as in dorsal, piliform scales basally, entire surface with lustrous iridescent shine. hindwing dorsal surface uniformly cinnamon pink, unmarked. Ventral surface rust brown, piliform scales basally lustrous as in male.

Abdomen: Elongate, broad, segments covered in dense pinkish red scales basally, light green distally, with moderately long piliform scale-tufts at apex.

Genitalia ( Figs 24–26 ). Dorsal plates broad and high, lightly sclerotised, widest medially, distal ends straight, setose proximally. Subanal plates short, narrow, horizontally oriented. Antevaginal lamella large, setose in two main disjunct patches on posterior margin, three indentations on posterior margin, central indentation with longer setae. Lateral lobes smooth. Ductus bursae elongate and narrow, with diverticulum long, ovoid, apex flattened, corpus bursae wider distally, sub-ovoid.

Variation: Like all other species in the A. tegulatus group, A. simonseni females have two distinct colour forms, one with the forewings, thorax, legs and abdomen apex grass green ( Fig. 8 ), and the other colour form with these areas a dark rusty-brown ( Figs 59, 61 ). The green colour form is more common in collections, and is the basis for the description.

Biology and phenology. Adult flight time is associated with the wet season, where adult emergence occurs during or just after rainfall from the 25 th of November to the 30 th of January. The species has been taken at light in monsoon rainforests particularly near swamps, creeks, in riparian or coastal situations ( Fig. 64 ) and larvae have been reared from the stems of Grewia breviflora Benth. (Tiliaceae) (David A. Lane pers. comm).

Remarks. This species is known only from the northern coastal regions and this may reflect a higher rainfall requirement as suggested by Simonsen (2018: plate 48B). The species is generally widespread in the top-end of the Northern Territory, where monsoon rainforest can be found in discrete patches within a vast area of 500,000 km 2 that are concentrated and most floristically diverse in the northern coastal regions ( Russell-Smith and Lee 1992) where rainfall is highest. The general dearth of specimens likely reflects an absence of targeted collection rather than a true absence, as Australian members of this genus are usually uncommon at light and synchronise a short flight time with specific weather events.

Though specimens have been photographed mating ( Figs 59–61 ), courtship behaviour has not been observed. The presence of meta-tibial androconial scales of the male, along with the distinctive saccharine scent discernible from living or fresh male specimens suggests that pheromones play a part in the mate attraction or courtship of Aenetus species ( Common 1990). Scales with lustrous iridescence are present on entire ventral surface of the forewing and hindwing of A. thermistis males and females, but both wings only in the female of A. simonseni while these scales are restricted to the forewing of the male. Comparatively large eyes may indicate a high visual acuity, this coupled with the dimorphism of iridescent scales on both sexes but particularly so in the female could suggest that a component of their courtship is visual as well as chemical. The Eurasian Hepialus humuli (Linnaeus) also have iridescent scales on the wings, as well as hind tibial androconia in the males, and employ a visual courtship strategy ( Anderson et al. 1998). Further dedicated study into the behaviour of Aenetus in general is required to document their courtship behaviour. Interspecific variation in eye size and degree of dimorphism, as well as variation in androconia extent (with the latter present in both sexes of A. montanus Tindale, 1953 and A. ombraloma ( Lower, 1902)) may suggest some level of interspecific variation in courtship behaviour.

Figures

FIGURE 64. Riparian-associated monsoon rainforest habitat of Aenetus simonseni sp. nov. from Adelaide River, NT. Figure courtesy of N. Volpe.

FIGURE 1–6. Adult male Aenetus spp: 1–2, A. simonseni sp. nov., holotype, 1, dorsal; 2, ventral; 3–4, A. thermistis, Atherton, QLD, 3, dorsal; 4, ventral; 5–6, A. maiasinus sp. nov., holotype, 5, dorsal, 6, ventral. Scale bars: 10 mm.

FIGURE 7–8. Adult female Aenetus spp. (all dorsal): 7, Aenetus simonseni sp. nov. paratype; 8, A. thermistis, Kuranda, QLD. Scale bars: 10 mm.

FIGURE 9–23. Male Aenetus genitalia; ventral, dorsal, lateral; 9–11, A. simonseni sp. nov. holotype, dissection ID EPB-010; 12–14, A. thermistis dissection ID 31-016384-EPB; 15–17, A. maiasinus sp. nov. holotype, dissection ID EPB-ANIC-021; 18– 20, valvae, 18, A. simonseni sp. nov. holotype; 19, A. thermistis, 20, A. maiasinus sp. nov. holotype; 21–23, sternite eight; 21, A. simonseni sp. nov. holotype; 22, A. thermistis; 23, A. maiasinus sp. nov. holotype; scale bars: 9, 12, 15, 21–23: 1 mm; 18–20: 500 μm. Abbreviations: brp—basal rim of pseudotegumen. ip—intermediate plate. jx—juxta. pt—pseudotegumen. sc—saccus. scu—sacculus. tp—twin processes of pseudotegumen. tr—trulleum. vi—vinculum. vl—valva.

FIGURE 24–29. Female genitalia of Aenetus spp, 24–26, A. simonseni sp. nov. paratypes; 24–25, dissection ID EPB-ANIC- 05; 26, dissection ID EPB-ANIC-18; 27–29, A. thermistis dissection ID 31-016407-EPB. Scale bars: 1 mm. Abbreviations: cb—corpus bursae. db—ductus bursa. div—diverticulum. dp—dorsal plate. lal—lateral area of antevaginal lamella. mal—medial area of antevaginal lamella. sub—subanal plate.

FIGURE 59–61. Mating pair of Aenetus simonseni sp. nov. from East Point, NT, 29 December 2018; 59, female (brown colour form) above, male below; 60, close-up anterior view of the male; 61, female, backlit. Fig. 59 courtesy of N. Volpe; Figs. 60–61, courtesy of C. Henderson.

FIGURE 56–57. Distribution records of Aenetus spp.; 56, the tegulatus complex in Australia, Papua New Guinea, Timor-Leste and south-eastern Indonesia, with A. simonseni sp. nov. (pink circle), A. maiasinus sp. nov. (white crossed circle), A. thermistis (black circle), A. tegulatus from Ambon Island (dark grey crossed circle) and at least one undetermined A. tegulatus complex species (light grey circle) sensu Grehan et al. 2018, modified from Grehan et al. 2018; 57, map of the Australian state of Queensland with recorded localities of A. trigonogrammus sp. nov..