Rytietia uncinata Diškus, Xu & Dai, 2023

Stonis, Jonas R., Diškus, Arūnas, Remeikis, Andrius, Orlovskytė, Svetlana, Solis, Alma, Paulavičiūtė, Brigita, Xu, Jiasheng & Dai, Xiaohua, 2023, Genera of Tischeriidae (Lepidoptera): a review of the global fauna, with descriptions of new taxa, Zootaxa 5333 (1), pp. 1-131 : 65-66

Rytietia uncinata Diškus, Xu & Dai , sp. nov.

urn:lsid:zoobank.org:act:6E9527F6-581B-4849-8840-74260093D6B3

( Figs 276–280 , 284, 285, 287–290 , 294, 296–302 .)

Type material. Holotype: Ô, VIETNAM: Lao Cai Province, Sapa, 22°21’44”N, 103°46’47”E, elevation 1850 m, feeding larva on Fissistigma chloroneurum (Hand.-Mazz.) Tsiang (see Remarks), 20.ii.2015, ex pupa iv.2015, field card no. 5202, leg. A. Diškus, genitalia slide no. AD1011 ( MfN) . Paratypes: 9 Ô, 4 ♀ , same label data as holotype, genitalia slides nos AD896 Ô (from adult in pupal skin), AD1012 ♀ ( MfN); 1 Ô, 1♀ , same label data data ( GNU).

Diagnosis. Externally, this new species is characterized by a distinct forewing pattern with a dark apical area; it makes R. uncinata sp. nov. immediately recognizable among all other Tischeriidae , except for the externally sometimes indistinguishable R. chongyiensis Xu & Dai , sp. nov. (described below). In the male genitalia, the combination of a one-lobed valva and extremely long basal projections of the phallus distinguish R. uncinata from all known Tischeriidae species. This species is also distinctive because of the elaborated juxta with two large apical lobes, each bearing a well-thickened but short spine. For differentiation of the male genitalia of R. uncinata from those of the related R. chongyiensis , see diagnosis of R. chongyiensis . In the female genitalia, R. uncinata is characterized by the extremely large ovipositor lobes and unique, distinctly reticulate antrum (in R. chongyiensis , antrum is non-reticulate or indistincly reticulate).

R. uncinata and R. chongyiensis also differ in their geographical distribution, different host plants, and shape of the leaf mines (see diagnosis of R. chongyiensis ).

DNA barcode. We barcoded one specimen of the type series, but not the holotype; the sequence is available in the GenBank database under accession number OQ413572.

Description. Male ( Figs 276, 278–280 ). Forewing length 3.9–4.1 mm; wingspan 8.4–9.0 mm (n = 10). Head: palpi and frons yellow ochre; pecten long, yellow-ochre; frontal tuft grey, golden shiny, yellow distally; collar yellow-ochre, comprised of lamellar scales; antenna slightly or distinctly longer than one half the length of forewing; flagellum grey, golden glossy or irregularly annulated with dark grey scales; basal part of flagellum usually golden cream. Tegula, thorax, and forewing intense yellow-ochre; apical area of forewing densely covered with dark grey-brown or black-brown scales; fringe blackish grey, pale grey to ochre cream on tornus; fringe line distinctive, comprised of black scales; forewing underside dark grey-brown, except for black special scales along costal margin on forewing base; no androconia. Hindwing dark brown-grey to black-grey on upper side and underside; fringe grey to ochreous grey. Legs yellow-ochre, covered with dark grey-brown scales on upper side. Abdomen grey-brown with some purple iridescence on upper side, yellow-ochre on underside; genital plates large, yellow-ochre; anal tufts long, mostly dorsal, pale grey to ochreous-yellow or golden cream.

Female ( Fig. 277 ). Forewing length 3.8–4.3 mm; wingspan 8.5–9.4 mm (n = 5). Similar to male, but frontal tuft dark grey-brown, golden yellow distally; collar sometimes grey-brown proximally; tegula and thorax speckled with grey-brown scales; basal half of forewing sometimes sparsely speckled with small dark scales. Otherwise, identical with male.

Male genitalia ( Figs 284, 285, 287–290 ) with capsule 790–805 µm long, 420–470 µm wide. Uncus comprised of two large lobes. Socii medium small, paired, membranous. Valva ca. 550 µm long, without a lateral “arm” or dorsal lobe. Anellus absent. Juxta large, 180–190 µm long, 120–150 µm wide, elaborated, with two large apical lobes, each bearing a well-thickened but very short spine. Vinculum large, rounded distally. Phallus 275–285 µm long, rod-like, with extremely long lateral projections basally.

Female genitalia ( Figs 294, 296, 297 ) ca. 1860 µm long. Ovipositor lobes unusually large, rounded, densely covered with peg-like setae; second pair of ovipositor lobes three times smaller, with numerous long setae. Posterior apophyses much longer than anterior apophyses, widened at tips; prela comprised of three pairs of rod-like projections; transverse processes of prela unusually wide. Antrum unique, angular and reticulate. Corpus bursae relatively long, oval-shaped, without distinctive pectination. Ductus spermathecae short, with about three small and one large coils, and small, elongated vesicle.

Bionomics ( Figs 298–302 ). Host plant is Fissistigma chloroneurum (Hand.-Mazz.) Tsiang (see Remarks) ( Fig. 299 ). Larvae mine leaves in February. Leaf mine is irregular but elongated, slender, often with lateral corridors, and with no frass. A nidus is inconspicuous. Adults occur in April. Otherwise, biology is unknown.

Distribution. This species is known from a single locality in northern Vietnam, near the border with China (Lao Cai Province: Sapa, Fig. 298 ), at the elevation about 1850 m.

Etymology. The species name is derived from Latin unicatus (hooked), in reference to the elaborated juxta with well-thickened spines in the male genitalia.

Remarks. The host plant, Fissistigma chloroneurum (Hand.-Mazz.) Tsiang, was identified solely on the basis of photographs taken in the field; no herbarium samples were preserved. F. chloroneurum is known to be a liana. However, according to the collector, the host was a tree. Therefore, the first two authors of this monograph are not fully certain about the accuracy of the host plant identification. If the host plant is identified correctly, then Fissistigma -feeding R. uncinata and R. chongyiensis Xu & Dai , sp. nov. (described below) provide a new host plant family, Annonaceae , for global Tischeriidae .

Figures

FIGURES 276–283. Adults of Rytietia spp. 276, R. uncinata Diškus, Xu & Dai, sp. nov., general view without abdomen, male holotype; 277, same, with abdomen, female paratype; 278–280, same, details of head, male paratypes (MfN); 281, R. chongyiensis Xu & Dai, sp. nov., right side, male paratype; 282, same, apex of forewing, male paratype; 283, same, general view, female paratype (GNU)

FIGURES 284–288. Male genitalia of Rytietia spp. 284, 285, R. uncinata Diškus, Xu & Dai, sp. nov., northern Vietnam, holotype, genitalia slide no. AD1011, capsule with phallus and juxta removed (MfN); 286, R. chongyiensis Xu & Dai, sp. nov., China, holotype, genitalia slide no. LIU0094, uncus and tegumen (GNU); 287, R. uncinata, holotype, genitalia slide no. AD1011, juxta; 288, same, phallus (MfN)

FIGURES 289–293. Male genitalia of Rytietia spp. 289, R. uncinata Diškus, Xu & Dai, sp. nov., northern Vietnam, paratype, genitalia slide no. AD896, capsule with phallus and juxta removed (a fresh mount in glycerol, not covered with a cover slip); 290, same, phallus and juxta (MfN); 291, R. chongyiensis Xu & Dai, sp. nov., China, holotype, genitalia slide no. LIU0094, juxta, phallus and valva; 292, 293, same, paratype, genitalia slide no. LIU0099, juxta and phallus (GNU)

FIGURES 294–297. Details of female genitalia of Rytietia spp. 294, 296, 297, R. uncinata Diškus, Xu & Dai, sp. nov., northern Vietnam, paratype, genitalia slide no. AD1012 (MfN); 295, R. chongyiensis Xu & Dai, sp. nov., China, paratype, genitalia slide no. LIU0097, apophyses (GNU)

FIGURES 298–305. Bionomics of Rytietia spp. 298, R. uncinata Diškus, Xu & Dai, sp. nov., northern Vietnam, Lao Cai Province, Sapa, at the elevation about 1850 m, habitat; 299, same, host plant (see Remarks); 300–302, same, leaf mines; 303– 305, R. chongyiensis Xu & Dai, sp. nov., China, leaf mines