Tetraneura (Tetraneurella) ovaliformis Watanabe, Sano & Akimoto 2022, sp. nov.
Creators: name: Watanabe, Tomoko
name: Lee, Wonhoon
name: Sano, Masakazu
name: Murakami, Keisuke
name: Akimoto, Shin-Ichi
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Aphididae
Tetraneura
Tetraneura ovaliformis

description: Tetraneura (Tetraneurella) ovaliformis Watanabe, Sano & Akimoto, sp. nov.
Tetraneura sp. O.: Akimoto 1995; Akimoto & Yamaguchi 1994, 1997: Tomisawa & Akimoto 2004; Muramatsu & Akimoto 2014, 2016
Fundatrix first instar nymph: Body elliptical, becoming thinner posteriorly, 0.62−0.71 (on average 0.65) mm long, 0.26−0.34 (0.30) mm wide on abdominal segment II, 0.39−0.46 (0.43) times as wide as long (Figure 4A). All tergites sclerotized strongly, except for the posterior part of each segment. No wax gland plates present. Eyes each with 3 ommatidia. Capitated setae present on antennae, legs, and whole body dorsally.
Antennae short, 5-segmented, smooth and not imbricated, 0.12−0.14 (0.13) mm long, 0.20 (0.20) times as long as body, 0.75−0.89 (0.81) times hind femorotrochanter length (Figure 4D). Antennal segment V as long as or slightly shorter than segment IV; processus terminalis indistinguishable. Antennal segment IV square-shaped, rather wider to the apex. Antennal segment III short, 1/5−1/4 length of segment IV. Primary rhinarium projecting as a horn with the tip not pointed, 0.009−0.016 (0.012) mm long on segment IV and 0.010−0.015 (0.012) mm long on segment V; that on segment V with 2−4 circular accessory rhinaria on the base. Segment V with 6−7 setae, of which the basal one is the longest with a conspicuously capitate tip, 0.031−0.059 (0.048) mm long. Antennal segment IV with 4−5 setae.
Head and prothorax completely fused. Head and prothorax with 5−7 pairs of setae dorsally, 1 pair on the vertex, 1−2 pair(s) ventrally and 2 pairs laterally. Meso- and metanotum each with 1 spinal pair, 1 pleural pair and 2 lateral pairs of setae. Dorsal and lateral setae on head and thorax capitated. Rostrum reaching hind coxae; ultimate rostral segment rather slender, 0.09−0.11 (0.10) mm long, 0.50−0.64 (0.57) times as long as hind femorotrochanter, with 12 setae. Legs smooth; fore femorotrochanter 0.11−0.14 (0.13) mm long, fore tibia 0.083−0.107 (0.097) mm long, hind femorotrochanter 0.15−0.19 (0.17) mm long and hind tibia 0.13−0.18 (0.16) mm long. Tarsal segment I completely fused with segment II, with an unsclerotized spot basally. One pair of dorsoapical setae on tarsus thick and capitate, 0.065−0.087 (0.074) mm long on hind legs. One pair of ventrobasal setae on tarsus tapering but not pointed, 0.058−0.076 (0.064) mm long on hind legs. One pair of empodial setae capitate, slightly longer than the claws. Spiracles with round rims, not projecting, 0.008−0.011 (0.010) mm in diameter.
Abdominal tergites I−VI each with 1 spinal and 1 lateral pair of setae; tergite I with 1 pleural pair additionally; tergites II−IV sometimes with 1 pleural pair additionally. Tergite VII with 1 spinal and 1 lateral pair of setae; tergite VIII and cauda each with 1 pair of spinal setae. Cauda with 4 setae ventrally. Spinal setae on tergite V 0.011−0.015 (0.013) mm long. Lateral setae on tergite II 0.015−0.024 (0.020) mm long, on VI 0.021−0.035 (0.029) mm long, on VII 0.033−0.043 (0.037) mm long. Dorsal and lateral setae on abdominal segments capitate.
Exule first instar nymph: Body rather elongate, posteriorly broadly rounded, mostly membranous with wax grand plates on the whole body except posterior abdominal segments, 0.84−0.88 (on average 0.87) mm long and 0.40−0.46 (0.43) mm wide, 0.47−0.52 (0.50) times as wide as long; eyes indistinct, with 3 ommatidia (Figure 5A).
Antennae short, 5-segmented, 0.32 (0.32) mm long, 0.37−0.38 (0.37) times as long as body, 1.31−1.38 (1.35) times as long as hind femorotrochanter. The length of antennal segment I 0.047 −0.049 (0.048) mm, II 0.056 −0.061 (0.059), III 0.024 −0.038 (0.030), IV 0.108 −0.130 (0.119), and V 0.045 −0.054 (0.049). Antennal segments I−III not imbricated and smooth, but segments IV and V imbricated with transverse rows of spinules. Segment I with 3−4 setae, II with 3−5, III with 0−2, IV with 10−18 and V with 6−7. Segment II cylindrical. Segment III thicker apically. Segment IV imbricated, cylindrical, slightly thicker apically, with 19−21 transverse rows of spinules, which are dense on the apical half. Primary rhinarium on segment IV with 1 oval opening, the outer circumference of which is ciliated with 2 tongue-like projections. Segment V wholly with transverse rows of spinules, with an undeveloped processus terminalis, the apex of which is truncated obliquely. Primary rhinarium on segment V with 2 openings, the outer circumferences are ciliated with 1−3 tongue-like projections.
Suture on head visible; antennal tubercles not developed; vertex nearly flat. Head with 5 pairs of setae dorsally, 1 pair on the vertex, 2−3 pairs ventrally. Rostrum reaching over the hind coxae; ultimate segment convergent almost straightly, 0.11−0.12 (0.11) mm long, 0.43−0.50 (0.45) times as long as hind femorotrochanter, with 14−16 setae.
Femorotrochanters, tibiae and tarsi smooth (Figures 5D, G). Fore femorotrochanters 0.20−0.21 (0.20) mm long and fore tibiae 0.18−0.19 (0.18) mm long. Hind femorotrochanters 0.24−0.26 (0.24) mm long, 0.34−0.42 (0.37) times as wide as long. Hind tibiae 0.24−0.26 (0.24) mm long. Tarsal segments I and II completely united without a slit. Hind tarsi 0.053 −0.060 (0.056) mm long; hind claws 0.074 −0.082 (0.079) mm long, 1.34−1.52 (1.41) times as long as hind tarsal length.
Body setae acute. Each thoracic segment pleurally with 2 pairs of setae. Each of abdominal segments I−VII pleurally with 1 pairs of setae. Mesonotum, metanotum and abdominal tergites I−VI spinally with 3 pairs of setae. Tergite VII with 1 or 2 pairs of spinal setae. Lengths of spinal setae on abdominal tergite III 0.034 −0.047 (0.040) mm long. Wax gland plates present on head, thoracic segments, and abdominal segments I−VII; head ventrally with 2 pairs of wax gland plates, which are nearly circular; prothorax with 1 pair pleurally; mesothorax and metathorax respectively with 2−3 small and inconspicuous pairs; abdominal segments I−VII respectively with 2−4 pairs, which are inconspicuous and circular or long oval (Figure 5K). Abdominal sternites III−VII respectively with 2−3 setae. Cauda dorsally with 1 pair of setae spinally, 1 pair laterally, and 1 longer pair ventrally.
Emigrant adult: Body 1.75−2.00 (1.84) mm long, without wax gland plates (Figure 6A). Head and thorax dark brown; antennae and legs brown. Wings wholly shaded in brown, slightly darker along veins.
Antennae 6-segmented, 0.65−0.72 (0.68) mm long, 0.36−0.38 (0.37) times as long as body, 0.98−1.08 (1.04) times as long as hind tibia (Figure 6D). Antennal segments III−VI pigmented thinly; segment V and VI imbricated with numerous transverse rows of spinules. Segment IV sparsely with spinules between secondary rhinaria in some individuals. Segments I−III not imbricated and smooth. Antennal segment III variable in length, 0.23−0.29 (0.25) mm long, 0.72−0.81 (0.75) times the length of IV, V and VI combined. Segment IV rather oval in profile, 0.43−0.46 (0.44) times as wide as long. Segment V 0.16−0.19 (0.17) mm long, 0.61−0.78 (0.69) times as long as segment III, 0.17−0.22 (0.19) times as wide as long at the middle point. Segment VI 0.38−0.47 (0.42) times as wide as long, thickest at the middle point, with a depression at the primary rhinarium, which is elongated transversely; segment VI wholly with spinules arranged in 14−15 transverse rows, without secondary rhinaria (Figure 6G). Secondary rhinaria present on segments III−V, narrow, slightly projecting, microscopically represented as blight lines on dark pigmented background, covering usually 2/3 or the whole circle of the segments from the ventral side. Antennal setae on segments III−V very short and scarce, present on the dorsal side; the longest seta on segment V 0.013 −0.017 (0.015) mm long; segment III with 1−2, IV with 0−2, V with 3−4 and VI with 4−5 setae, of which 3 are present apically and 1−2 on the basal half.
Suture on head invisible; antennal tubercles not developed; vertex nearly flat. Head dorsally with 4−5 and ventrally with 6−11 pairs of setae, respectively; of them, 3−7 pairs of ventral setae situated near the base of clypeus. Rostrum short, not reaching the middle point between the coxae of fore and middle legs. Ultimate rostral segment short, with gently convex margins and 6 pairs of short setae, 0.078 −0.103 (0.086) mm long, 0.50−0.58 (0.53) times as long as the second segment of hind tarsi (Figure 6J). Femorotrochanter not imbricated and smooth; hind femorotrochanter 0.43−0.54 (0.48) mm long, 0.69−0.76 (0.72) times as long as hind tibia. Tibiae slightly spinulose at the terminal; hind tibia 0.60−0.74 (0.65) mm long. Tarsi with numerous spinules neatly arranged in transverse rows; first tarsal chaetotaxy 3:3:3; second segment of hind tarsus 0.15−0.18 (0.16) mm long; empodial setae almost the same length as claws (Figure 6M). Abdomen wholly membranous, with short setae. Cornicles absent. Genital plate slightly brown-pigmented, with 30−44 (35.4) setae (Figure 6P). Cauda semicircular, with 2 setae. Fore wings with unbranched media; the veins rather broad, not conspicuously bordered. Hind wings only with 1 inconspicuous oblique vein.
Sexupara adult: Since the sexupara is morphologically close to the emigrant in many respects, the characters that differ between the two morphs and are indispensable for identification will be referred to.
Body 1.80–2.07 (1.95) mm long. Wax gland plates present on the whole body except the posterior segments of abdomen (Figure 7A).
Antennae 6-segmented, 0.78–0.94 (0.86) mm long, 0.43–0.46 (0.44) times as long as body, 1.12–1.13 (1.12) times as long as hind tibia (Figure 7D). Antennal segments III–VI pigmented thinly; segments V and VI imbricated with numerous transverse rows of spinules; segment IV sparsely with spinules between secondary rhinaria; segments I–III not imbricated and smooth; segment III 0.28–0.39 (0.33) mm long, 1.32 times as long as that of the emigrant, 0.70–0.93 (0.84) times as long as segments IV, V and VI combined; segment IV rather oval in outline, 0.45–0.59 (0.51) times as wide as long; segment V cylindrical, 0.20–0.25 (0.23) mm long, 0.14–0.20 (0.16) times as wide as long, 0.60–0.80 (0.69) times as long as segment III; segment VI 0.063–0.076 (0.071) mm long, 0.39–0.48 (0.44) times as wide as long, with the middle thickest; segment VI with spinules arranged in 15–16 transverse rows, without secondary rhinaria. Primary rhinarium present on segment VI, tongue-like, elongate transversely with ciliated rims (Figure 7G). Secondary rhinaria present on the segments III–V, 0.002–0.005 (0.003) mm wide, slightly projecting, microscopically represented as the blight lines on dark pigmented background, covering usually 1/2 to the whole circumference from the ventral side, more numerous than in emigrant. Antennal setae short and scarce, present on the dorsal surface, 0.014–0.019 (0.016) mm long on segment V.
Suture on head invisible; antennal tubercles not developed; vertex nearly flat. Head dorsally and ventrally with 6 pairs of setae, respectively; of them, 4 pairs of ventral setae situated near the base of clypeus. Median ocellus and 1 pair of wax gland plates situated posteriorly to the ocellus, forming a triangle (Figure 7J). Ultimate rostral segment 0.10–0.11 (0.10) mm long with 7 pairs of setae, convergent with almost straight margins, 0.60–0.67 (0.64) times as long as the second segment of hind tarsus, 1.20 times as long as that of the emigrant (Figure 8A). Pronotum with 2 pairs of wax plates spinally and 1 pair of them pleurally; metanotum and mesonotum each with 1 pair of them spinally. Femorotrochanter and tibia slightly longer than those of the emigrant. First tarsal chaetotaxy 3:3:3. The second segment of hind tarsus slightly shorter than that of the emigrant; second segment of hind tarsus 0.21–0.22 (0.21) times as long as hind tibia (in emigrant, the proportion is 0.24–0.27 (0.25)). Abdominal tergites membranous without sclerites (Figure 7A). Wax gland plates present on the first to seventh abdominal tergites, 1 pair spinally, 1 pair marginally, and sometimes 1 pair of small ones pleurally; round or oval in the outline, with variation in the size, consisting of 1–50 (23) minute round facets (Figure 8G, J). Cornicles present on the pleural and posterior positions of the fifth abdominal tergite, 0.039 –0.053 (0.045) mm in diameter, with slightly projecting rim, which is sclerotized slightly (Figure 8M). The first to sixth abdominal tergites with 6–10 short setae, respectively; the seventh tergite with 6–8 long setae. The second to sixth abdominal sternites with 16–20 short setae, respectively. Dorsal, abdominal setae 0.017 –0.034 (0.023) mm long on segment III spinally, 0.074 –0.109 (0.087) mm long on segment VIII pleurally. Genital plates slightly brown-pigmented, with 13–23 (16.7) setae on each of the right and left sides (Figure 8P).
Host plant: Primary host: Ulmus davidiana var. japonica. Secondary host: Setaria spp. and other gramineous species.
Paratypes: Fundatrix first instar nymph: 30 exs, Sapporo, Hokkaido, V.1994, on U. davidiana var. japonica, S. Akimoto; 4 exs, Teshikaga, Hokkaido, 27.VII.1985, on U. davidiana var. japonica, S. Akimoto. Emigrant adult: 8 exs, Sapporo, Hokkaido, 20.VI.1984, on U. davidiana var. japonica, S. Akimoto; 12 exs, Sapporo, Hokkaido, 17.VI.2000, on U. davidiana var. japonica, M. Sano. Exule first instar nymph: 1 ex., Sapporo, Hokkaido, 14.IX.1985, on grass roots, S. Akimoto; 4 exs, Hirosaki, Aomori, 30.IX.1983, on grass roots, S. Akimoto; 1 ex, Hirosaki, Aomori, 29.IX.1983, on grass roots, S. Akimoto. Sexupara adult: 10 exs, Sapporo, Hokkaido, 15.X.1985, on U. davidiana var. japonica, S. Akimoto.
Holotype: Emigrant adult: Hokkaido Univ., Sapporo, Japan, 20.VI.1984, on U. davidiana var. japonica, S. Akimoto leg. The holotype and other specimens examined are deposited in The Hokkaido University Museum, Sapporo, Japan.
Distribution: Japan (Hokkaido, Aomori).
Etymology: from globular shape of the gall.
description: Published as part of Watanabe, Tomoko, Lee, Wonhoon, Sano, Masakazu, Murakami, Keisuke & Akimoto, Shin-Ichi, 2022, Taxonomic revision of the Tetraneura akinire species group (Insecta, Aphididae, Eriosomatinae), with description of a new species and a correction of a nomenclatural confusion, pp. 162-186 in Zootaxa 5183 (1) on pages 172-177, DOI: 10.11646/zootaxa.5183.1.14, http://zenodo.org/record/7070086