Aenetus maiasinus Beaver & Moore & Grehan & Velasco-Castrillón & Stevens 2020, sp. nov.

Aenetus maiasinus Beaver & Moore, sp. nov.

(Figs 5–6, 15–17, 20, 23)

Type specimens: Holotype ♂, ANIC.

Type locality: Maia Cove, Kimberley Region, Western Australia, Australia.

Etymology. This species is named for the collection locality of the holotype, with the suffix – sinus a Latin noun that translates to ‘bay’ or ‘cove’. A noun in the nominative singular case.

Type material. HOLOTYPE. (in ANIC): ♂. Maia Cove, Kimberley, WA, December 2017, J & A. Koeyers, 14°12’52.081”S, 126°7’6.431”E, ID no. KCS 18—2083 / dissection no. EPB-ANIC-021 / ANIC 31-071240.

Distribution. Known only from Maia Cove, northern Western Australia (Fig. 56).

Diagnosis. This is the only member of the Hepialidae presently recorded from the tropical north of Western Australia. Aenetus maiasinus sp. nov. is a distinctive pale species which can be differentiated from A. thermistis externally by the hindwing entirely white compared with broad swathes of pink and blue along the costal, tornal and inner margin of the hindwing in A. thermistis. The forewings are paler than either A. thermistis or A. simonseni, and the medial line is straighter than in either species. Sternite eight of A. maiasinus sp. nov. has the anterior edge truncate unlike either species, and has only a single central tooth on the posterior margin, unlike A. simonseni which has three. Aenetus maiasinus sp. nov. further differs from either species in male genitalia; the apodemal vinculum is proportionally broader with lateral margin slightly convex, unlike A. thermistis which is straight, or A. simonseni which is slightly concave. The paired posterior projections are shorter than in A. thermistis, but more pronounced than in A. simonseni. The saccus is significantly broader with the sulcus set closer to the margin of the apodemal vinculum than in either of A. thermistis or A. simonseni. The intermediate plate of A. maiasinus sp. nov. is rectangular, similar to A. thermistis, however has a single lateral ridge that A. thermistis lacks. The most significant differences are present in the valvae, where in A. maiasinus sp. nov. the apical spine is proportionally shorter than the middle and basal spines, somewhat similar to the condition in A. thermistis but the basal spine nearest to sacculus is more curved, and the sacculus is shorter.

Description. Male (Figs 5–6). Forewing length: 30 mm, hindwing 23 mm, expanse: 62 mm. Head: Antennae as long as head and slender, filiform, pale brown, covered with fine sensilla chaetica, flagellum without scales; scape globular, pedicel ovoid, 25–30 flagellomeres. Eyes prominent, larger than head capsule, almost meeting dorsally. Scales on frons and vertex dense and olive green. Labial palpi three segmented, palpomeres rectangular, basal two subequal, distal shortest, rectangular with apex blunt.

Thorax: Pro- and mesothorax dorsally and ventrally covered in fine olive green to cream scales and interspersed with orange scales on ventral surface. Legs olive green with brown scales at proximal end of femur, tibia and tarsus; epiphysis triangular, apex rounded, less than ¼ length of femur; hind leg with ochreous metatibial tuft of long androconial scales. Arolium u-shaped.

Wings: Forewing: broad and triangular. Costa slightly concave centrally and convex towards apex. Apex point- ed, wing margin straight at apex, outer margin-tornus area rounded with gently curved tornus. Wing venation classically hepialine. Hindwing: broad, triangular with pointed apex, tornus rounded. Dorsal forewing ground colour light cream with an even, slightly curved transverse band along medial line from costa to CuA2. Basal side of line paler cream, fading into ground colour, proximal olive green lowlights between CuA2 and Rs3. Faint mottled patterns of alternating lighter and darker cream colours across wing surface, extensive near outer wing margin. Pale orange and cream piliform scales around jugum. Costa light olive green with five dark brown bars, final bar distal to medial line. Costal-discal area light olive green. Ventral surface overall mottled cream with pale orange piliform scales medially and basally. Patch of green scales present at margin between costa and tornus. Areas with pale orange scales are lustrous iridescent. Hindwing dorsal surface white, costa, tornus and anterior margin cream. Inner margin with orange piliform scales anteriorly. Posterior discal cell narrowly triangular, narrowing towards base, final discal cell narrower, triangular, basally covered with white piliform scales. Ventral with entirely yellowish-green, with whitish-blue scales in discal area.

Abdomen: Long, narrow, basally covered in white scales. Sternite eight (Fig 23) roughly sub-ovoid with anterior edge truncate, posterior edge unsclerotized, with short central tooth and pronounced lateral corners.

Genitalia (Figs 15–17): Apodemal vinculum broad, slightly wider than long in posteroventral view, lateral margin slightly convex, with paired posterior projections subtle and sub-rounded. Saccus sub-triangular, broad, flattened distally. Intermediate plate sub-rectangular, single lateral ridge. Basal rim of pseudotegumen narrow, sub-triangular, dorso- and distoposterior margins of pseudotegumen smooth, sub-rounded and lightly sclerotized. Twin processes reduced, blunt, pitched back towards basal rim. Ventral pseudoteguminal arm present, narrow and pointed, becoming membranous. Valva (Fig. 20) lightly sclerotised, with three heavily sclerotised large spines, valva narrower at proximal end, with subglobular sacculus. Viewed posteroventrally, valvae curve away from pseudotegumen. Tip of valva ends as apical spine tapering to sharp point, pointing ventrally in habitus away from abdomen. When viewed laterally (Fig. 17) this spine is positioned at near right angle, with tip straight. Apical spine smallest; mid spine, curved, tip pointing anteriorly, inner edge with small indentation; basal spine nearest to sacculus shorter than middle spine, hooked, oriented well away from sacculus. Long, fine setae present on tip of dorsal surface, shorter setae present between spines and along inner lateral margin. Juxta broad, flattened and U-shaped. Truellum membranous.

Female. Unknown.

Biology and phenology. Larval biology unknown. The specimen was collected in December, indicating that the species likely has a northern wet season flight period not unlike other members of the ‘ tegulatus’ complex.

Remarks. The dissection is affected by mould which interfered with visibility of some features and imaging but clear diagnostic differences are nevertheless observable, particularly in the valva and apodemal vinculum. The species may be found to be more widespread in the high rainfall area of the Kimberley region, as the presumed habi- tat of monsoon rainforest totals up to 7000 ha in scattered, isolated patches across 170,000 square km (Kenneally 2018). Lepidoptera are rarely collected from this region due to its general inaccessibility, which likely explains the absence of available material in major institutions. The single specimen was collected on a boat anchored at the cove (J. Koeyers pers. comm).