Aenetus trigonogrammus 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 : 460-461

Aenetus trigonogrammus Beaver & Moore , sp. nov.

( Figs 30 , 34–36, 40, 42 , 62 )

Type specimens: Holotype ♂, ANIC . Paratypes: 1 ♂ UQIC .

Type locality: Fig Tree Creek, 27.5 km SW of Gin Gin, Queensland, Australia.

Etymology. The name trigonogrammus is derived from Greek trigono (triangle) and grammi (line) in reference to the triangular white marking on the male forewing, where the white medial line meets the dorsum. A noun in the nominative singular case.

Type material. HOLOTYPE. (in ANIC): ♂. Fig Tree Creek (Perry River), 27.5 km SW of Gin Gin, Qld, 25°13’14”S, 151°51’01”E, 27 October 2011, P.J. and Q.A. Hendry / ANIC 31-071241 .

PARATYPES. 1 ♂ ( UQIC). Toowoomba , Queensland, Australia, E.J. Dumigan, 25 January 1960 / Dissected by E.P. Beaver, dissection no. UQIC-EPB-01’ (in UQIC) .

Distribution. South-eastern Queensland ( Fig. 57 ), where the type specimen was collected 27.4 km SW of Gin Gin. and a further specimen from Toowoomba.

Diagnosis. Along with the similar ‘splendens’ group species found in Queensland— A. lewinii ( Figs 31 , 63 ), A. ligniveren ( Fig. 33 ), and A. splendens ( Fig. 32 )—the male of A. trigonogrammus sp. nov. is distinguished from of the other Queensland Aenetus species such as A. edwardsi Simonsen , A. eximia , A. mirabilis Rothschild , A. scotti , A. ramsayi (Scott) , and A. thermistis by the presence of a narrow white submarginal band from costa to tornus and baso-tornal patches of white on the forewing. The male of A. trigonogrammus is distinguished externally from the other ‘ splendens’ species by the white triangular patch along the dorsum at the posterior terminus of the submarginal line, and by having the basal triangular marking entirely white. The genitalia are superficially similar only to A. lewinii ( Figs 37–39, 41, 43 ), but may be distinguished particularly by the pseudotegumen shape, which in A. trigonogrammus sp. nov. is large and rounded, whereas in A. lewinii it is smaller relative to the basal rim, and subtriangular. The valvae are similar to that of A. lewinii , however, they are less strongly sclerotised, and broader centrally, with the area distal to the sacculus narrower. The eighth sternite has sharper anterio-lateral corners while the apodemal vinculum is broader and with paired anterior projections however the anterior end in A. lewinii is variable with respect to the presence or absence of paired anterior projections in some specimens. The intermediate plate is not fused with the basal rim of the pseudotegumen, whereas in A. lewinii it is.

Description. Male ( Fig. 30 ) Forewing length: 24–27 mm, hindwing 18–21 mm, expanse: 50–55 mm. Head: Antennae longer than head and slender, filiform, densely ciliated, pale brown, 33 flagellomeres, scape cuboid, pedicel flattened ovoid. Eyes prominent, same height as head capsule, almost meeting dorsally. Scales on frons and vertex dense and white. Labial palpi three segmented, basal two palpomeres rectangular, apical elliptical, middle longest, apical palpomere shortest.

Thorax: Pro- and mesothorax dorsally and ventrally covered in white scales and interspersed with olive green and scales on ventral surface; dorsal prothorax white, base of wing green, posterior end white in lateral view. Legs white and olive green, with long white piliform scales proximally from middle of tibia and tarsus; dark brown longitudinal line along length of mesotibia; epiphysis short, broad, apex pointed; hind leg white with ochreous metatibial tuft of androconial scales. Arolium elliptical.

Wings: Forewing broad and triangular. Costa slightly concave centrally and convex towards apex. Apex point- ed. Wing venation hepialine. Hindwing broad, subtriangular, tornus rounded. Forewing dorsal ground colour olive green, darker green lines in discal area; an uneven muted white band along medial line from costa to tornus, where it widens to a white triangle; a second triangle on anal margin in discal area, characteristic of the splendens group of species, filled white. A short, separate white basal line is present from dorsum near jugum, extending to CuA 2 in the basal area, fusing with discal triangle at CuA2. Costa white, becoming light green at apex. Tornus distal to medial line suffused with whitish-grey scales between M3 and just beyond CuA2. Ventral hindwing dorsal surface white, margin at apex light green, margin elsewhere faint bluish green; basal area covered with white piliform scales. Ventral surface as above except basal area bluish-green.

Abdomen: long, narrow, white piliform scales dorsally and ventrally. Ventral apex with aqua blue scales. White forked tuft of piliform scales at apex. Sternite eight ( Fig. 42 ) sub-square except strongly concave posterior margin.

Genitalia ( Figs 34–36 ). Apodemal vinculum broad and short, with paired anterior projections rounded. Saccus uniformly sub-triangular, broad. Intermediate plate laterally compressed, free, with anterior indentation near sacculus. Basal rim of pseudotegumen broad, high in lateral view, disto- and ventroposterior margins of pseudotegumen broad, rounded, lightly serrate. Ventral pseudoteguminal arm sclerotised. Valva ( Fig 40 ) large, broad at proximal end, with long, blunt sacculus. Viewed posteroventrally, valvae curve laterally away from pseudotegumen. Apex of valva rounded, sub-apical area tapering to a sharp point, pointing vertically away from abdomen. When viewed laterally the apical spine is positioned almost horizontally with tip curving slightly ventrally. A large curving hook from distal sacculus points vertically down and is more curved than the sub-apical spine. Fine setae sparsely present between basal hook and apex, with denser patch of hairs between sacculus and hook. Juxta flattened and U-shaped. Truellum membranous.

Variation. Variable number of darker green lines within the light green baso-discal area; extent of white suffusion beyond medial line. The paratype is smaller than the holotype, with forewing length 24 mm.

Female. Unknown.

Biology and phenology. Larval biology unknown. The holotype ( Figs 30 , 62 ) was collected at light during rainfall (P. Hendry pers. comm.). The site is mostly subtropical Eucalyptus woodland with mixed understorey and dry vine thicket at the edge of a seasonal creek ( Fig 65 ). Aenetus species, particularly those in the splendens group of species, are often associated with host plants growing in close proximity to creek-lines, in riparian vegetation ( Beaver 2019b). The two known specimens are from late October to late January.

Remarks. The authors (EPB & MDM) visited southern Queensland in late 2019 but failed to locate further specimens of this species, which is expected to be highly localised. Only two specimens are known from what is a heavily cleared and populous area of Australia. Southern Queensland has a significantly high level of Hepialidae diversity for Australia ( Simonsen 2018), — generally within rainforests or wet forest environments which makes the discovery of this new species unexpected. Aenetus trigonogrammus sp. nov. is allopatric to all other splendens - group species at the northern site near Gin Gin, however further south at Toowoomba it would appear to overlap in the general vicinity with A. splendens , A. lewinii and A. ligniveren ( Simonsen 2018) . The first author has taken each species in a distinct habitat, and rarely together, suggesting that their range at the local-scale may be closely tied to habitat preference: A. splendens in subtropical rainforest and rainforest edge, A. lewinii in coastal wallum swamp and open Melaleuca-Banksia woodland with a diverse heath layer ( Beaver & Grehan 2018), and A. ligniveren in temperate woodland or Eucalyptus wet forest ( Beaver 2019b). The main exception being that A. splendens will occasionally occur in temperate woodland very near to A. ligniveren if rainforest elements are present in the general vicinity. Specimens of those three species were recorded from the Burdekin River, north Queensland by Simonsen (2018) who remarked that the locality data for these specimens was likely incorrect. Although this may be the case for A. ligniveren and A. splendens , a further male specimen of A. lewinii is in the SAMA collection and labelled from Cairns, far north Queensland. The species is also present in central Queensland at the Blackdown Tableland ( Simonsen 2018) and so may be found to be further sympatric with A. trigonogrammus sp. nov. in southern Queensland.

Figures

FIGURE 65. Dry subtropical Eucalyptus woodland and riparian-associated habitat of Aenetus trigonogrammus sp. nov. from near Gin Gin, Qld. The holotype was taken to light at the shed in centre left. Figure courtesy of P. Hendry.

FIGURE 30–33. Male ‘splendens group’ Aenetus spp. that occur in southern Queensland (all dorsal); 30, A. trigonogrammus sp. nov., holotype; 31, A. lewinii, Brisbane, QLD; 32, A. splendens, Brisbane, QLD; 33, A. ligniveren, Koorine, SA. Scale bar: 10 mm.

FIGURE 34–43. Male Aenetus spp. genitalia, ventral, dorsal, lateral. 34–36, A. trigonogrammus sp. nov. paratype, dissection ID UQIC-EPB-01; 37–39, A. lewinii, Lennox Head, NSW, dissection ID EPB-001; 40–41, valvae; 40, A. trigonogrammus sp. nov. paratype; 41, A. lewinii; 42–43, sternite eight; 42, A. trigonogrammus sp. nov. paratype, 43, A. lewinii. Scale bars: 34, 37: 1 mm; 40–43: 500 μm.

FIGURE 62–63. Live habitus of male Aenetus spp., 62, holotype A. trigonogrammus sp. nov. at light sheet; 63, reared A. lewinii, Lennox Head, NSW. Fig. 62 courtesy of P. Hendry.

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..