Triozidus ukogi ( Shinji, 1940 ), 2025

Liao, Yi-Chang, Inoue, Hiromitsu & Percy, Diana M., 2025, The psyllid genus Triozidus Li, 1994 stat. rev. sensu novo (Hemiptera: Psylloidea: Triozidae) in East Asia is redefined with the addition of two new species from Taiwan inducing galls on the leaflet petiolules of Eleutherococcus trifoliatus (Araliaceae), Zootaxa 5727 (1), pp. 113-139 : 126-128

Triozidus ukogi ( Shinji, 1940) comb. nov.

( Figs 8–11 )

Trioza ukogi Shinji, 1940: 66 .

Heterotrioza ( Dyspersa) ukogi : Klimaszewski (1973: 248).

Heterotrioza ukogi : Kwon & Kwon (2020: 221); Cho et al. (2022: 72) .

Lunatrioza ukogi Kwon, Suh & Kwon, 2022 : nomen nudum [conference poster, not a published work in the sense of the International Code of Zoological Nomenclature].

Material examined. JAPAN • 6♂ 7♀; Honshu, Tochigi Pref., Utsunomiya City, Kamikuwajima-machi ; 36.525 N, 139.949 E, 92 m; 28 Oct 2014; Rikio Sonobe leg.; Eleutherococcus spinosus (leaf petiole and petiolule galls); HIC, NHCU, dry, slide mounted and in ethanol . 29 immatures; same data but 10 Oct 2023; NHCU, slide mounted and in ethanol . 18♂ 7♀; Honshu, Tochigi Pref., Utsunomiya City, Shimotokami-cho ; 36.527 N, 139.846 E, 100 m; 16 Oct. 2015; Rikio Sonobe leg.; Eleutherococcus spinosus (leaf petiole and petiolule galls); HIC, dry mounted and in ethanol . 46 immatures, same data but 10 Oct. 2023; HIC, in ethanol . 1♂; Honshu, Tochigi Pref., Utsunomiya City, Nagaoka-cho ; 36.593 N, 139.881 E, 150 m; 13 Oct. 2015; Rikio Sonobe leg.; Eleutherococcus spinosus ; HIC, in ethanol .

Description. Adult ( Figs 8A , 9 , 10 ). Coloration. Body color yellowish.Antennae yellow with apices of segments 4 to 6 dark brown, and entire segments 7 to 10 black. Compound eyes dark brown. Ocelli orange. Legs brown. Forewing pale yellow, transparent, with pale brown patch around clavus. Hindwing transparent, except clavus brown.

Structure. Body medium-sized, length from anterior head margin to tip of folded forewing 4.8–5.1 mm, female generally larger ( Fig. 8A ); covered in short fine setae. Head ( Fig. 9A ) slightly narrower than thorax. Vertex width 1.7 x length, with short pubescence. Genal processes prominent, length along mid-line 0.8 x vertex length, divergent, conical, subacute at apex, medium-long pubescence. Antenna ( Fig. 9A ) length approximately 1.5 x head width, antennal segment 3 approximately double length of segment 4, relative length of flagellar segments as 1.0: 0.5: 0.3: 0.3: 0.3: 0.3: 0.2: 0.2; two unequal terminal setae: longer seta 1.1 x, and short truncate seta 0.2 x, segment 10 length. Thorax moderately arched dorsally, minutely pubescent. Hind leg ( Fig. 9D ) metatibia length 1.0–1.1 x head width. Forewing broad ( Fig. 9B ), length 5.7 x head width, and 2.5 x width, widest slightly distal to the middle; wing apex subacute; vein Rs very long, sinuous and curved to apical margin; vein M evenly curved with bifurcation anterior to line connecting apices of veins Rs and Cu 1a; cell m 1 slightly larger than cell cu 1; vein Cu 1a evenly curved, vein Cu 1b more or less straight; veins minutely pubescent. Hindwing ( Fig. 9C ) 0.7 x as long and 0.5 x as wide as forewing.

Male terminalia ( Fig. 10A–C ). Proctiger short, with slight posterior lobes reaching maximum expansion in the basal half, covered in long setae except for basal third laterally ( Fig. 10A ). Subgenital plate subglobular, with medium long setae laterally; posterior dorsal margin slightly convex. Paramere ( Fig. 10B ) longer than proctiger; in profile more or less parallel sided and straight, irregularly narrowing to apex which is acute and directed inward and rearward; inner face beset with long setae. Distal aedeagus segment ( Fig. 10C ) distinctly shorter than paramere ( Fig. 16 ), markedly curved medially with broad semi-circle projections, apical portion inflated into a broadly curved hook with bluntly rounded apex; sclerotized end tube of ductus ejaculatorius short, slightly sinuous. Female terminalia ( Fig. 10D ) cuneate, slender; proctiger narrowing in apical fourth with acute apex, dorsal margin straight, only slightly longer than subgenital plate, with long setae in the apical half, anal ring length one fourth proctiger length, consisting of a single row of pores. Subgenital plate, in profile, triangular, apex acute, beset with long hairs laterally and ventrally. Ovipositor dorsal valvulae cuneate, ventral valvulae straight apparently without serrations apically.

Fifth instar immature ( Fig. 11 ). Coloration. General color yellow. Forewing pad and thorax also yellow. Body ( Fig. 11A ) length 1.3 x width. Body surface, including margin of head, wing pads ( Fig. 11C ), caudal plate and legs covered with sparsely distributed medium-short to long simple setae. Antenna ( Fig. 11E ) relative length of antennal segments 3 to 8 as 1.0: 0.7: 0.3: 0.6: 0.4: 1.8. Legs ( Fig. 11A–B ) as for generic description. Forewing pad length 2.7 x width, and 2.5–2.7 x antenna length. Caudal plate length 0.8 x width. Circumanal ring ( Fig. 11D ) peanut-shaped (medial constriction from anterior and posterior), width 0.3 x caudal plate width; outer ring composed of a single narrow row of elongate pores, inner ring composed of elongate pores.

Host plant. Eleutherococcus spinosus in Japan ( Shinji, 1940); several other Eleutherococcus spp. ( E.divaricatus , E. sieboldianus , E. nodiflorus ) have been mentioned for South Korea ( Kwon 1983; Kwon & Kwon 2020) but both hosts and distribution records remain doubtful (see Cho et al. 2017) or need to be confirmed.

Biology. Induces multi-chambered, spindle-shaped galls on the leaf petiole, petiolules and rarely on young twigs ( Shinji 1940; Miyatake 1996).

Distribution. Japan ( Shinji 1940; Miyatake 1996), South Korea (according to Kwon & Kwon 2020, but needs confirmation; see Cho et al. 2017).

Comment. We only examined material from Japan. Occurrences reported for South Korea were partly misidentification of Triozidus stackelbergi (see Cho et al. 2017; Kwon & Kwon 2020). Kwon & Kwon (2020) list this species as a pest on medicinal Eleutherococcus spp. in South Korea.

Genetic resources. Adult sequences of COI were all slightly divergent, three haplotypes: PQ817987– PQ817989.

Figures

FIGURE 8. Triozidus ukogi adults, immature and galls on Eleutherococcus spinosus. A, adults (male above), female (lateral and dorsal views, below) (images: Yorio Miyatake); B, immature within gall chamber (above) detail of immature (below); C, closed “spindle-shaped” gall on the petiole; D, petiolule gall. Scale bar in A 1 mm.

FIGURE 9. Adult Triozidus ukogi comb. nov. A, head and antennae; B, forewing; C, hindwing; D, hind leg. Scale bars: 0.1 mm (A, D); 1 mm (B, C).

FIGURE 10. Terminalia of Triozidus ukogi comb. nov. A, male terminalia (lateral view); B, paramere (inner surface); C, distal portion of aedeagus showing medial broadly semicircular projections (arrowed); D, female terminalia (lateral view). Scale bars: 0.1 mm.

FIGURE 11. Fifth instar immature of Triozidus ukogi comb. nov. A, habitus; B, tarsal arolium showing asymmetric development of tarsal claws (vestigial claw arrowed); C, forewing pad marginal simple setae; D circumanal ring showing single narrow row of elongate pores (inset); E antenna. Scale bars: 0.1 mm.

FIGURE 16. Phylogenetic placement of Triozidus in family Triozidae is indicated by a black square representing a subgroup within Group B (see Percy et al. 2018), the related genera are expanded on in the text. An asterix indicates the placement of the type species of Heterotrioza, H. chenopodii in Group D, and Trioza, T. urticae in Group M, and Dyspersa sensu Cho et al. (2022) in Group A. Configuration of the three Triozidus taxa to one another based on the 714 bp COI fragment data (unique haplotypes only) is shown, with T. burckhardti placement indicated based on the backbone analysis (see text); taxon placements within Triozidus are uncertain in both analyses due to short internal branches and low to moderate bootstrap support, with a slightly different taxon configuration recovered in the ML backbone constraint analysis (see text). Illustrations of forewing, paramere and aedeagus are shown for all six Triozidus species to indicate comparative sizes; an asterisk by T. ceratophorus and T. eleutherococci indicates the illustrations are redrawn with reference to Li (2011) and Konovalova (1980, 1988) respectively, and in these cases paramere and aedeagus may not be to scale, plus the apex of the aedeagus is partly obscured in the illustration for T. eleutherococci. The annotation of the mitogenome of T. yangorum is graphically represented at top right.