Pectinivalva (Casanovula) minotaurus Hoare

Hoare, Robert J. B. & Nieukerken, Erik J. van, 2013, Phylogeny and host-plant relationships of the Australian Myrtaceae leafmining moth genus Pectinivalva (Lepidoptera, Nepticulidae), with new subgenera and species, ZooKeys 278, pp. 1-64 : 27-29

Pectinivalva (Casanovula) minotaurus Hoare sp. n.

Material examined.

Holotype. ♂, 27.36S 151.59E, Leslie St., Toowoomba, Qld, emg. 19.ii.1996, Lophostemon confertus , R.J.B. Hoare, I.F.B. Common. Paratypes. 2♂, 6♀, same data as holotype, emg. 2.-27.ii., 1.iii.1996, slide 11325 (anic); 11♂, 17♀, same locality, emg. 2.i.-2.ii.2001, Lophostemon confertus , R.J.B. Hoare, C. van den Berg, genitalia slides CvdB110, EvN 3539, 3547 (rmnh); 3♀, 27.33S, 151.59E, Prince Henry Heights, Toowoomba, Queensland, emg. 15, 18.ii.1986, Lophostemon confertus , I.F.B. Common, slide 10209 (anic); 1♂, 1♀, Brisbane, Queensland, emg. 30.xii.1957, Lophostemon suaveolens , I.F.B. Common, slides 11507, 11582 (anic); 1♂, Goodna, [Queensland], 8.iv.1906, [A.J. Turner], slide 11506 (anic).

Description.

Male (Fig. 8). Wingspan 4.7-5.5 mm. Head capsule (Figs 27-30): labial palpi 3-segmented; segment 2 reduced, maxillary palpi with ratio of segments from base approximately 0.3: 0.8: 0.6: 1.7: 1.0; interocular index 0.57; vertex with a pair of sclerotized crests. Frontal tuft ferruginous; collar ferruginous; eyecaps white, posteriorly leaden; antennae with flagellomeres in basal ½ greatly dilated and flattened, tapering beyond this, shining lead-grey, yellowish beneath, ca. 43-48 segments. Thorax and tegulae dark fuscous with purplish reflections. Forewing to ½ dark fuscous with bluish and purplish reflections; beyond this dark fuscous with bronzy reflections; a shining pale golden fascia at 2/3, apex of wing at base of cilia with purplish reflections; cilia grey beyond a line of fuscous-tipped scales, pale brownish around apex. Hindwing grey, unmodified; cilia grey. Abdomen with T2-3 shining brassy golden, remaining tergites shining dark lead en with green and violet reflections; T4 laterally with contiguous groups of androconial scales of two types: inner scales scallop-shaped, finely ridged; outer scales calyx-shaped, coarsely ribbed; T5 with similar area of androconia consisting entirely of scallop-shaped scales (Figs 37, 38), these showing as velvet black crescents on abdomen in situ.

Female (Fig. 9). Wingspan 4.7-5.8 mm. Similar to male, but antennae not dilated at base, ca 21-24 segments; abdomen entirely leaden with brassy reflections.

Male genitalia (Figs 46-48, 62, 63). Capsule ca. 360-375 μm. Anterior extension of vinculum reduced to curved lateral struts, i.e. vinculum anteriorly H-shaped. Uncus subtriangular, bilobed, with a compact tuft of setae arising from dorsal side of each lobe near tip. Gnathos with elongate central element and short lateral arms. Valva (Fig. 47) ca. 235 μm, squarish, caudal margin very straight; pectinifer consisting of ca. 29 narrow elements. Transtilla absent. Aedeagus (Figs 48, 63) 545 μm, with single broad, blunt apical process. Vesica with numerous close-set spine-like cornuti in several groups.

Female genitalia (Fig. 75, 86-88). Total length 800-880 μm. T9 with ca 9 setae on each side. Apophyses anteriores reduced to rounded stubs; apophyses posteriores narrow, much longer than anteriores. Lateral sclerotizations of vestibulum narrow, bent inwards, tips squared off. Ductus spermathecae with 1 ½ convolutions. Posterior part of corpus bursae very convoluted; anterior part with many coarse pectinations in right half; left half with a few fine pectinations only; no further sclerotizations in corpus.

Larva. Green. Head (Fig. 106) parallel-sided; length of head ca. 250 μm; width ca. 215 μm. Thorax: prothoracic sternite as in Fig. 111. Chaetotaxy as described for subgenus; T2 with 11 pairs of setae (L3 present), A10 probably with 3 pairs (but 1 pair possibly lost in slide examined). Anal rods distinctly forked posteriorly.

Biology.

Host plants: Lophostemon confertus (R.Br.) Peter G.Wilson & J.T.Waterh.and Lophostemon suaveolens (Sol. ex Gaertn.) Peter G.Wilson & J.T.Waterh. ( Myrtaceae ). Egg: invariably on upperside of leaf. Mine (Fig. 118): commences as very long narrow gallery with black linear frass, leaving narrow clear margins, broadens rather abruptly into an irregular wide gallery or elongate blotch, sometimes with gallery parts, with central line of black frass or in the case of the blotch, frass concentrated on one or both sides; exit-hole on underside, an almost circular hole. Cocoon (Fig. 125): dark reddish brown. Occupied mines have been collected on 6 and 17 July and 15 August. A male pupa (pharate adult) is shown in Figs 126, 127.

Diagnosis.

Very similar externally to Pectinivalva (Casanovula) brevipalpa in both sexes; diagnostic characters are listed under that species.

Distribution.

Southern Queensland.

DNA barcode.

RMNH.INS.23539, Genbank KC292478 and RMNH.INS.23547, Genbank KC292477, both identical.

Derivation.

The species is named after the famous beast of Greek mythology, the Minotaur. The name (a noun in apposition) refers to the extraordinarily expanded and flattened male antennae, which are likened to the Minotaur’s horns.

Remarks.

The antennae of the male are the most strongly modified of any known species of Nepticulidae . Although many male-specific head structures in other insects are utilized in male-male competitive interactions over mates (e.g. the lateral cephalic projections of Phytalmia spp, Tephritidae ( Moulds 1977)), such direct competition is unknown in Lepidoptera , and the antennae of minotaurus are more likely to function in close-range courtship, along with the androconial scales on the male abdomen. Similar widened flagellomeres are known from the genus Thisizima Walker, 1864 in Tineidae ( Yang et al. 2012). The androconial scales are also remarkable, two distinct types being present in contiguous patches on the abdominal dorsum.