Metura aristocosma Beaver 2020, comb. n.
Creators: name: Beaver, Ethan P.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Lepidoptera
Psychidae
Metura
Metura aristocosma

description: Metura aristocosma (Lower, 1908) comb. n.
(Figs 2 A–B, 3E–F, 4G–H, 6A, 7C, 7H)
= Oiketicus aristocosma Lower, 1908: pp. 112. Nielsen et al. 1996: pp. 35.
Holotype: ♂, with associated larval bag (Fig. 6A) and pupa, ‘ Oiketicus aristocosma Low. Type. / Kuranda, Qld, Aust., F.P. Dodd / SAMA no. 31-017604’ in SAMA (Fig. 2 A–B, 3E–F).
Type locality: Kuranda, Queensland, Australia.
Additional material examined: 10 specimens (4 imago ♂, 6 larval bags). SAMA: 2 ♂ Kuranda, Qld, Aust., Jan 1907 (one with Feb 1908), F.P. Dodd / SAMA no. 31-017605 and 31-017606, latter with Dissection ID EPB-021. 1 larval bag in AM: Daintree, Qld, Nov. 1970, R. Laid, AM K264362. 1 larva and bag in EPBC: (in ethanol) 16 Feb 2019, Speewah area, N Qld, Aust., M. Connors, on Rhodamnia sp. in rainforest. 1 in ANIC: 1 ♂ and associated larval bag, 15 March 2007, Top of the Range, 19 Butler Drive, Kuranda, Qld, Aust., 335 m, D.C.F. Rentz. 3 larval bags in (NBCN): Andai, Papua, 1903. 2 additional larval bags, no data.
Diagnosis. Metura aristocosma is the largest of this genus with a wingspan of 63 mm, and is readily distinguished by the absence of a foretibial epiphysis. Male Metura aristocosma have the mesoscutum entirely black, a feature shared only with M. oceanica, and M. phyllosacca. Metura oceanica has a triangular patch of orange scales at the dorso-anterior aspect of the abdomen, which in M. aristocosma is entirely black. Metura aristocosma may be distinguished from M. phyllosacca by comparison of head and patagium scale colouration. In M. aristocosma the frons is entirely yellow, while in M. phyllosacca it is mixed with dark brown scales. Additionally, the patagium of M. aristocosma has a broad patch of black scales medially, which in M. phyllosacca is reduced and less distinctive. Sternite VIII is distinct from all species in that the lateral margins are straight. The genitalia also differ from both M. oceanica and M. phyllosacca by uncus shape, which is distinctly more triangular in those species. Additionally, the saccus is evenly tapering in those species whereas it broadens sharply towards the vinculum in M. aristocosma. The vesica of the phallus in M. aristocosma is elongate and in this way is similar to M. phyllosacca however it is less strongly recurved and less heavily spined. The mature larva is distinctive, the black markings present on the head and pronotal shield of M. oceanica and M. elongatus are greatly reduced in this species, which has a mostly cream-coloured shield with yellow highlights towards the posterior edge, and black lines that extend only marginally beyond the spiracle, less than ½ the length of the shield. Young individuals lack the yellow highlights, and are predominately cream and black. The larval bag is distinctive and unlike any known in this genus, it is comprised of short fragments of sticks and excised leaf veins, with no bare areas of silk visible, and has a ‘brush-like’ appearance. The mature bag is the longest in this genus, 203–245 mm, and 27 mm width (Fig. 6A).
Redescription. Male. (Fig. 2 A–B, 3E–F) Forewing length 26 mm, hindwing 15 mm, expanse 63 mm.
Head. Scape club like, broad, rounded at posterior apex, anterior apex ½ width of posterior. Pedicel flattened, disc-like. Scape and pedicel clothed with yellow scales. Antennae bipectinate, apex filiform, 48 flagellomeres, ochreous scales on first 1/4 dorsal flagellomeres, setose, rami 8x width of flag at widest. Frons round, yellow, vertex yellow. Labial palps greatly reduced, two segmented, both subequal rectangular, apex triangular.
Thorax. Patagium and tegula yellow, patagium centrally with black triangular marking, mesoscutum black interspersed with grey medially, mesoscutellum black. Ventral as for dorsal. Forelimb femur yellow-ochreous, tibia and tarsus black, mid- and hindlegs black. When cleared all heavily sclerotised (Fig. 5H), all tibiae with rounded node at ventral anterior apex. Foreleg without epiphysis, femur ventrally convex distally, straight basally. Mid and hindleg without tibial spurs. Forewing elongate, triangular; costa concave medially, gently convex toward pointed apex, termen convex medially, inner margin straight posteriorly, convex anteriorly. Hindwing costa slightly convex, apex pointed, termen convex, inner margin greatly expanded, convex, triangular at 3A. Both forewing and hindwing surface black, distal ends of all veins lightly scaled, transparent. Underside similar.
Abdomen. Black on all tergites, intersclerite membrane yellow-ochreous scaled, some yellow-ochreous scales on posterior tergite margins at abdomen apex. Ventral anteriorly black on first two sternites, remainder yellow. Sternite VIII broad (Fig. 4M), paired anterior apophyses irregularly angular at apex, anterior margin deeply concave, posterior-lateral corners at right angles
Genitalia. (Fig. 4 G–H). Saccus narrow, elongate, posterior margin narrow ‘V’ shaped, heavily sclerotised towards vinculum. Vinculum with vincular arms straight, parallel on inner margin with saccus, outer margin concave towards tegumen. Tegumen outer margin slightly concave. Uncus broad, wider than high, posterior apex weakly convex, bifurcate, setose on dorsal aspect, obtuse angle where lateral corners meet posterior. Transitellar arms weakly sclerotised, anterior margin straight, posterior convex. Valvae broad, apexes bifurcate to two lobes, ventral lobe shorter, hooked, short spines at apex, inner dorsal margin setose with many short spines, sacculus round, heavily spined at apex, otherwise smooth. Phallus elongate, ventrally concave, dorsally convex, ductus ejaculatorius heavily spined, vesica extensive, ventrally recurved, spined, dorsal aspect rounded.
Female. Unknown.
Larva. Figure 7C. Head cream coloured, unmarked. Pronotal shield of thorax cream, yellow highlights posteriorly, posterior margin black, spiracle black, black line laterally from posterior margin to just beyond the spiracle, <½ the length of shield, second black line closer to median, ½ length of first line. Anterior margin with black spot centrally. Meso- and metathorax black, with three ovoid yellow markings laterally. Thoracic legs black, heavily sclerotised.
Larval Bag. Figs 6A, 7H. 203–245 mm length, 27 mm width. Light caramel brown, densely adorned with short fragments of twigs and excised leaf veins, with no bare areas of silk visible, ‘brush-like’. Posterior aperture with several small 4–10 mm fragments of leaf foliage.
Distribution. Figure 9A. Known from the Wet Tropics region of far-north Queensland, Australia, such as from Kuranda, Atherton, Cairns, Speewah, Smithfield, Julatten, Jourama, Paluma, as well as from the Eastern Highlands of Papua New Guinea, such as from near Kabifua, (D. Fischer pers. comm.) and Bulolo (Dobunaba & Schneider 1999) and from Indonesia, West Papua: Andai. These disparate sightings may indicate a wide distribution in the highlands of New Guinea, which is under-sampled for most moths including Psychidae.
Biology and phenology. Metura aristocosma is known from Syzygium, Eucalyptus, Xanthostemon, Rhodamnia (Myrtaceae), Breynia (Phyllanthaceae), Banksia, and Grevillea and is likely polyphagous in a similar way to M. oceanica and M. elongatus. This species is known from tropical rainforest (Fig. 10D) and rainforest edge, particularly disturbed areas, however will also occur in tropical dry forest. The larva of M. aristocosma constructs the distinctive, brush-like larval bag by selecting a short section of a fresh twig which is carefully split longitudinally into fine, narrow filaments of wood pulp, an apical end of which is sown into the bag near the anterior aperture. Gradually larger filaments and sections of twig are added as the larva increases in size. Small portions of leaves and leaf veins are present at the posterior aperture of known larval bags, possibly indicating that the early instar case design is temporarily leafy as in young M. elongatus. Adult male specimens are very rare in collections, however larvae are more commonly (if irregularly) encountered (M. Connors pers. obs.). The adults are known from January and March. All known specimens appear to have been reared and it is unknown if the species is attracted to light.
Remarks. The species was originally placed in Oiketicus in Lower’s original description (Lower, 1908) however was correctly excluded from this genus by Nielsen et al. 1996 as ‘unplaced species in Psychidae’. The species conforms to the diagnosis provided herein for Metura, and for this reason is here transferred. The wings of the holotype (Fig 2 A–B) are worn, as such the wing description is based on a specimen also collected by Dodd in SAMA which has the body worn but is the only specimen the wings intact (SAMA no. 31-017605). A specimen with the larval bag 245 mm in length is known (J. Hasenpusch pers. comm), which is the largest known example of a larval bag constructed by any species in the family Psychidae. The larval bags are sometimes used as decoration in ceremonial dress and in net bags (bilum) by the Kainantu-Goroka language-group peoples near Goroka, PNG (D. Fischer pers. comm).
description: Published as part of Beaver, Ethan P., 2020, Revision of the genus Metura (Lepidoptera: Psychidae) with description of two new species, pp. 188-210 in Zootaxa 4861 (2) on pages 199-202, DOI: 10.11646/zootaxa.4861.2.2, http://zenodo.org/record/4414734