Oxycanus ephemerous Beaver & Moore, 2020

Beaver, Ethan P., Moore, Michael D., Velasco-Castrillón, Alejandro & Stevens, Mark I., 2020, Three new ghost moths of the genus Oxycanus Walker, 1856 from Australia (Lepidoptera: Hepialidae), Zootaxa 4732 (3), pp. 351-374 : 353-355

Oxycanus ephemerous Beaver & Moore , sp. nov.

( Figs 1A , 3 K–L, 4A–C, 7A, 10A)

Type specimens: Holotype male, SAMA . Paratypes, 2 males, SAMA .

Type locality: Inman Valley, Fleurieu Peninsula, SA, Australia.

Etymology. The specific name (Greek εφήμεΡΟΣ) refers to the ephemeral nature of the adult insect, which is known to fly for a brief period at a specific time of the year, in very few locations.

Type material. HOLOTYPE, male; ( SAMA). ♂, 20 May 2018, Inman Valley , Fleurieu Peninsula, South Aus- tralia, 35°29’01.0”S, 138°26’12.2”E, 180m elevation, coll. S. Eden, pres. E. P. Beaver, / Spec. No. 1862 leg removed for tissue storage MD Moore. / SAMA Database No. 31-019818.

PARATYPES, 2 males; ( SAMA) 2 ♂, Amer. River , K.I. 20 May 1952, F. M. Angel / SAMA database no. 31- 019191 / Dissection ID 31-019191-EPB; second male with SAMA database no. 31-019190.

Distribution. Known from Inman Valley, Fleurieu Peninsula; and from American River, Kangaroo Island, South Australia ( Figs 11 , 14 ).

Diagnosis. This species is similar to Oxycanus subvaria ( Figs 1B ; 3 I–J; 4D–F, 7B, 8A & D). However, it differs primarily in the shape and proportions of the male genitalia. In particular the vinculum is narrower and more square, and the saccus is much broader, rounded and shorter in O. ephemerous sp. nov. than in O. subvaria . In addition, the pseudotegumen is differently shaped in the new species. In O. ephemerous sp. nov. the ventral pseudoteguminal arms are distinctly shorter and the basal rim is less rounded and not as sclerotized as in O. subvaria . Both species have sternite 8 fused with the saccus ( Fig. 8A & D for O. subvaria Fig. 7A for O. ephemerous sp. nov.). The antennal rami of O. subvaria are equal to the width of the flagellomere in the middle of the antennae, while the rami of O. ephemerous sp. nov. are longer than the width of the flagellomere ( Fig. 3K & L ). The only other Oxycanus species to occur nearby to the known localities of O. ephemerous sp. nov. is O. niphadias (Meyrick) from the Southern Lofty Ranges. However, this species has longer antennal rami, at least 3x the width of the flagellomere, and distinctly different genitalia. The pseudotegumen in Oxycanus niphadias has a single central tooth, lacking invagination, and the S8 is pocket-like and depressed well into the vinculum. These structural differences are obvious enough to be observed in specimens without dissection or a microscope. The distributions of the widespread O. occidentalis Tindale, 1935 and O. ephemerous sp. nov. may overlap at the Kangaroo Island location, however, the larger (FW: 30 mm) O. occidentalis is closely allied to O. niphadias (see discussion) except for the presence of 2–5 enlarged spines on the pseudotegumen and extensive white patterns in the medial and sub-marginal areas of the forewing.

Description. Male. ( Fig. 1A ) Head: labial palpus three segmented, short, less than half length of head, directed forwards, second palpomere longer than first, third palpomere shortest, sub-orbicular, covered in dark grey scales. Antennae ( Figs 3 K–L) 7 mm, 43 flagellomeres, pale yellow, quadripectinate, each flagellomere with pair of broad, flattened rami oppositely-situated. Length of central primary rami almost twice width of flagellomere while proximal and distal primary rami are shorter and flattened. Primary rami ciliated, hairs longer distally. Ventral surface with short ridge adjoining thickened proximal bar, also heavily ciliated. Scape cylindrical, pedicel ovoid, flattened. Eyes larger than head capsule, widely separate. Scales on frons and vertex dense and dark brown.

Thorax: pro- and mesothorax dorsally and ventrally covered in dark brown scales and interspersed with cinnamon brown scales on dorsal surface, with greater suffusion of cinnamon brown on ventral surface. Wings: FW length 22–24 mm, expanse 45–48 mm, broad, triangular. Costa slightly concave centrally, convex towards apex. Wing venation oxycanine ( Fig. 10A ), vein 2A absent. HW 17–18 mm, triangular at apex, narrower, tornus rounded, vein CuP partly membranous. Dorsal FW ground colour mix of grey and buff scales, dark brown at costa, basal area; fringe grey; dark brown scales on all veins. Three yellow-cream spots present basally, within discal cells, in triangular configuration, indistinct in worn or faded specimens. Some specimens with four irregular cream marginal and sub-marginal bands from Rs2 to CuA 2, with brown scales between and adjacent to these bands. Ventral surface as for dorsal, veins highlighted with short, grey scales, cells between veins sparsely covered with long grey hair-like scales, pale cream markings absent. Darker scales at apex and margin. Lighter brown piliform scales present along costa and basal area, scales cinnamon brown basally. HW dorsal surface brown, darker brown at apex, sparsely scaled and semi-translucent within discal area. Costa and veins with pale cinnamon brown scales, scales on veins less elongate. Wing margin light cinnamon brown, fringe dark brown. Basal area and fringe along dorsum with long light cinnamon piliform scales, tending towards orange or blush red in fresh specimens. HW ventral surface as dorsal, except with dark brown margin, dark brown scales over wing veins. Fringe buff-grey, sparsely covered in longer hair-like scales. Legs dark brown dorsally and ventrally, grey on tarsus ventral surface, femur and tibia with brown piliform scales ventrally, broadly triangular, short epiphysis on fore-tibia, aerolium present.

Abdomen: narrow, tapering, tergites at proximal end with blush-red piliform scales when fresh, gradually merging with shorter brown and cinnamon brown scales towards distal end. Rounded tuft of blush-red piliform scales on final tergite. Ventral surface dark brown. Sternum 8 broad and rectangular, posteriorly becoming membranous, junction with saccus indistinct.

Genitalia ( Figs 4 A–C, 7A, diss. no. 31-019191, paratype male). Disto-posterior arm of saccus broad, and concave, trapezoidal, at right angles to sternite 8. Disto-posterior arm of vinculum narrow. Intermediate plate narrow, rectangular, free. Pseudotegumen: basal rim narrow, globular; dorso-posterior and disto-posterior margins narrow in postero-ventral view highly sclerotized. Dorso-distal twin processes short, apex rounded. Ventro and disto-posterior margin of pseudotegumen in lateral or 3-quarter views are a large, curved axe-head shape, with a deep invagination present just before ventral pseudoteguminal arms, both of which are short and fused with proximal points very short and free. Juxta broad, subrectangular, bilobate at anterior margin. Trulleum trapezoidal, semi-transparent. Valvae: elongate and lobate, flattened laterally, rounded apically, wider distally, sacculus short and oval, internal surface densely covered with long curved setae. Apex of valvae in line with dorso-posterior margin of pseudotegumen. Apodemal vinculum broad and short, posterior margin rounded. Fusion of sternum 8 and saccus forming a continuous structure. Para-anal sclerite absent.

Female. Unknown.

Habitat. Oxycanus ephemerous sp. nov. is known only from South Australia, from the Fleurieu Peninsula and Kangaroo Island bioregion (Inman Valley and American River respectively). The Inman Valley site is mainly farmland with some low Eucalyptus woodland and a shrub/heath and sedge understory, near a seasonal creek (S. Eden pers. obs.). Both these locations fall within an area of annual rainfall of 400–600 mm, among the wettest parts of the state. Similar conditions and habitats exist on the central-western part of Kangaroo Island and on the Eyre Peninsula and Yorke Peninsula, however, the species is not recorded from those locations. Oxycanus ephemerous sp. nov. occurs in a distinctly drier habitat compared to that of the similar O. subvaria , a species which occurs primarily in tall Eucalyptus wet forest, rainforest, montane wet forest, and sub-alpine woodland ( Edwards & Green 2011; Kallies et al. 2015) in eastern Victoria, central-coastal and south-eastern NSW and Tasmania in areas of rainfall above 800–1000 mm annually.

Remarks. The two species Oxycanus ephemerous sp. nov. and O. subvaria have allopatric distributions separated by approximatelty 630 km between Inman Valley and Melbourne. Oxycanus niphadias is the only other Oxycanus species currently identified as a South Australian endemic. Three specimens from the Grampians, VIC, in the Melbourne Museum listed as O. niphadias ( Kallies et al. 2015) were examined by the authors from photographs (provided by J. Schubert) along with a specimen from Halls Gap, VIC in SAMA and all are considered to be O. occidentalis Tindale , the first records for this species from Victoria. Oxycanus occidentalis also occurs in south-west WA ( Tindale 1935) and in South Australia on the Eyre Peninsula, Riverland and Kangaroo Island (M. Hura, A. Kallies pers. comm. and MDM pers. obs.). All three O. ephemerous sp. nov. specimens were collected on the 20 th of May in both 1952 and 2018, following rainfall the day before ( Australian Bureau of Meteorology 2019). The larval biology of O. ephemerous sp. nov. is unknown. A concerted effort was made by the authors to locate additional specimens of O. ephemerous sp. nov. and O. niphadias in April and May of 2018 and 2019 without success. The apparently restricted distribution and localised nature of the records raises concerns in a conservation setting, as both species, but particularly O. niphadias , may be threatened with extinction due to urbanisation and loss of habitat. Further work is required to determine the conservation status of these species.

Figures

FIGURE 1 (A–F). Adult male Oxycanus species: A, Oxycanus ephemerous sp. nov. holotype, ©SAMA; B, Oxycanus subvaria lectotype; C, Oxycanus flavoplumosus sp. nov. holotype, photo by T. Simonsen, ©Trustees of the NHM; D, E, O. flavoplumosus sp. nov. paratypes, ©SAMA; F, O. byrsa, courtesy of J. Schubert. Scales 10 mm.

FIGURE 3 (A–L) Antennae of male Oxycanus spp. A, B, O. byrsa; C, D, O. flavoplumosus sp. nov; E, F, O. determinata; G, H, O. petalous sp. nov.; I, J, O. subvaria; K, L, O. ephemerous sp. nov. Abbreviations: br—bar. ra—primary rami. ri—ridge. Scale bar in A–C is 500 µm; D is 200 µm; E, F is 500µm; G is 150µm H, I is 250 µm; J is 250 µm; K is 500 µm; L is 250 µm.

FIGURE 4 (A–F) Oxycanus spp. male genitalia.A–C O. ephemerous sp. nov. dissection ID 31-019191-EPB; D–F O. subvaria dissection ID 31-019120-EPB. Abbreviations: brp—basal rim of pseudotegumen. dpa—disto-posterior arm of vinculum. dsadisto-posterior arm of saccus. ip—intermediate plate. jx—juxta. pst—pseudotegumen. sc—saccus. scc—sacculus. s8—sternite 8. tp—twin process of pseudotegumen. tr—trulleum. v—apodemal vinculum. va—valva. vpa—ventral pseudoteguminal arms, ©SAMA.

FIGURE 7 (A–F) Oxycanus spp. male genitalia, 3-quarter view. A, O. ephemerous sp. nov. dissection ID 31-019191-EPB; B, O. subvaria dissection ID 31-019120-EPB; C, O. determinata dissection ID 31-018441-EPB; D, O. flavoplumosus sp. nov. dissection ID 31-018762-EPB; E, O. byrsa dissection ID 31-018407-EPB; F, O. petalous sp. nov. dissection ID EPB-ANIC-1, ©SAMA.

FIGURE 8 (A–F) Oxycanus spp. male S8. A, O. subvaria dissection ID 31-019120-EPB; B, O. byrsa dissection ID 31-018407- EPB; C, O. petalous sp. nov. dissection ID EPB-ANIC-1; D, lateral view of S8 and saccus connection of O. subvaria dissection ID 31-019120-EPB; E, O. flavoplumosus sp. nov. dissection ID 31-018762-EPB; F, O. determinata dissection ID 31-018441- EPB, ©SAMA.

FIGURE 10 (A–C) Oxycanus spp. male wing venation, forewing and hindwing. A, Oxycanus ephemerous sp. nov.; B, Oxycanus flavoplumosus sp. nov.; C, Oxycanus petalous sp. nov.

FIGURE 11. Distribution records of three new Oxycanus species: grey circle—Oxycanus petalous sp. nov.; filled circle—Oxycanus ephemerous sp. nov.; empty circle—Oxycanus flavoplumosus sp. nov.

FIGURE 14. Inman Valley, Fleurieu Peninsula, South Australia. Highly degraded habitat of Oxycanus ephemerous sp. n., ©Ethan P. Beaver.