Acalypta alutacea, Souma, 2025

Souma, Jun, 2025, A new species and two new records of the moss-feeding lace bug genus Acalypta (Hemiptera, Heteroptera, Tingidae) from Hokkaido, northern Japan, with an illustrated key to the Japanese species of the genus, ZooKeys 1229, pp. 107-132 : 107-132

Acalypta alutacea sp. nov.

Figs 1 A, B , 3 A – D , 5 A , 7 A – D , 9 A , 11 A , 13 A, B , 14 A, B , 15 A Japanese name: Kushiromaru-gunbai

Acalypta sp.: Nakatani (2016: 50) (distribution); Nakatani (2018: 48) (distribution).

Material examined.

Holotype, Japan • brachypterous ♂; Hokkaido, Kushiro-gun, Kushiro-cho, Beppo ; 27 Jun. 2024; J. Souma leg.; SIHU . Paratypes, Japan • 1 brachypterous ♂ 4 brachypterous ♀♀; same data as for holotype; SIHU • 1 brachypterous ♂ 1 brachypterous ♀; “ 春採湖北岸 ” [= Hokkaido, Kushiro-shi, Shunkodai, North shore of Harutori Lake ]; 8 Jul. 2015; M. Nakatani leg.; SIHU. Two specimens collected in 2015 were recorded as “ Acalypta sp. ” in a previous study ( Nakatani 2016) .

Diagnosis.

Acalypta alutacea sp. nov. is recognized among the other species of Acalypta based on a combination of the following characteristics: brachypterous morph only known; hemelytron without dark spots (Fig. 1 A, B ); antenniferous tubercle obtuse, curved inward (Figs 3 A – D , 13 A, B ); basal part of antennal segment III not thickened; rostrum reaching anterior part of abdominal sternite II (Fig. 5 A ); pronotum 3 / 4 times as long as maximum width across paranota; pronotal disc as long as calli; punctures on pronotal disc smaller than areolae of posterior process; posterior part of hood usually triangular; lateral carina of pronotum absent or reduced, shorter than hood, without or with a single minute areola; calli smooth; paranotum as wide as hood, not narrowed posteriorly, with 3–4 rows of areolae throughout its length; anterolateral angle of paranotum rounded, not or weakly protruding anteriorly, not reaching mid-level of compound eye; posterolateral angle of paranotum protruding posteriorly; posterior process strongly protruding posteriorly, as long as hood; costal area of hemelytron with 2–3 rows of areolae in basal part, a single row in middle part, and 1–2 rows in apical part (Fig. 7 A – D ); discoidal area expanded beyond apical fourth of hemelytron, wider than subcostal area; Cu (cubitus) vein distinct throughout its length; abdomen pale brown in female (Fig. 11 A ); and pygophore roundly inflated (Fig. 14 A ).

Description.

Brachypterous male. Frontal spine of head, pronotum except for calli, hemelytron, and sternal laminae pale brown; antenniferous tubercle, antennal segments I to III, ventral surface of thorax except for sternal laminae, and legs brown; most parts of head, antennal segment IV, calli, and abdomen dark brown; paranotum and hemelytron sometimes irregularly dark in very small sections, without dark spots; areolae of pronotum and hemelytron transparent; compound eyes dark red; pubescence on body yellowish (Figs 1 A , 3 A, B , 5 A , 7 A, B , 9 A ).

Body ovate; pubescence on most parts of body distinctly shorter than radius of compound eye (Figs 1 A , 3 A, B , 5 A , 9 A ). Head covered with minute pubescence; pair of frontal spines separated at apices, reaching apex of clypeus; antenniferous tubercle obtuse, curved inward, shorter than frontal spine; vertex and clypeus smooth. Compound eye round in dorsal view. Antenna densely covered with minute pubescence in segments I to III and long pubescence in segment IV; pubescence on segment IV longer than pubescence on other parts of body; segment I cylindrical, shorter than segment IV; segment II conical, shortest amongst antennal segments; segment III linear, longest amongst antennal segments, not thickened in basal part; segment IV fusiform. Bucculae closed at anterior ends, with 3 rows of areolae at highest part. Rostrum reaching anterior part of abdominal sternite II.

Pronotum (Figs 3 A, B , 13 A, B ) glabrous, 3 / 4 times as long as maximum width across paranota. Pronotal disc coarsely punctate, as long as calli; punctures smaller than areolae of posterior process. Hood roof-shaped, shorter than median carina of pronotum, wider than vertex at widest part, not covering compound eye, with 5 rows of areolae at highest part; posterior part usually triangular. Median carina straight, extending to apex of posterior process, with a single row of areolae throughout its length. Lateral carina absent or reduced, shorter than hood, without or with a single minute areola. Calli smooth. Paranotum horizontally expanding outward, as wide as hood, not narrowed posteriorly, with 3–4 rows of areolae throughout its length; anterolateral angle rounded, not or weakly protruding anteriorly, not reaching mid-level of compound eye; posterolateral angle protruding posteriorly. Posterior process triangular, obtuse at apex, strongly protruding posteriorly, as long as hood.

Hemelytron (Fig. 7 A, B ) glabrous, extending beyond apex of abdomen; apex close to the other at rest; costal area with 2–3 rows of areolae in basal part, a single row in middle part, and 1–2 rows in apical part; subcostal area with 4 rows of areolae at widest part; discoidal area expanded beyond apical fourth of hemelytron, wider than subcostal area, with 4–5 rows of areolae at widest part; sutural area with 3 rows of areolae at widest part; hypocostal lamina with a single row of areolae throughout its length; Sc (subcosta), Hc (hypocosta), R + M (fused radius and media) and Cu (cubitus) veins distinct throughout their respective length.

Thoracic pleura (Fig. 5 A ) smooth in anterior part, coarsely punctate in posterior part. Ostiolar peritreme reduced. Mesosternum narrower than metasternum. Sternal laminae lower than buccula, open in both anterior and posterior ends; metasternal lamina as high as mesosternal lamina. Legs (Fig. 1 A ) smooth, covered with minute pubescence; femora thickest at middle.

Abdomen ovate in dorsal and ventral views, glabrous except for terminalia, smooth. Pygophore (Figs 9 A , 14 A ) roundly inflated, semicircular in ventral view, covered with minute pubescence; anterior margin concave in middle part. Paramere (Fig. 14 B ) slender, expanded in middle part, gently curved inward, covered with minute pubescence in middle part of outer and inner margins.

Measurements (n = 3). Body length with hemelytra 2.30–2.60 mm; maximum width across hemelytra 1.30–1.50 mm; length of antennal segments I to IV 0.15 mm, 0.10 mm, 0.70–0.80 mm, and 0.20–0.25 mm, respectively; pronotal length 0.70–0.80 mm; pronotal width across paranota 1.10–1.20 mm; hemelytral length 1.65–1.85 mm; maximum width of hemelytron 0.70–0.80 mm.

Brachypterous female. General habitus very similar to that of male (Figs 1 B , 3 C, D , 7 C, D , 11 A ) except for the following characters: abdomen pale brown; body usually longer and wider than in male; antennal segment III shorter than in male; and apical part of abdomen pentagonal in ventral view.

Measurements (n = 5). Body length with hemelytra 2.60–2.80 mm; maximum width across hemelytra 1.65–1.80 mm; length of antennal segments I to IV 0.15 mm, 0.10 mm, 0.60 mm, and 0.20 mm, respectively; pronotal length 0.80–0.90 mm; pronotal width across paranota 1.20–1.30 mm; hemelytral length 1.90–2.00 mm; maximum width of hemelytron 0.85–0.95 mm.

Remarks.

Among all the species of Acalypta , A. alutacea sp. nov. strongly resembles A. carinata and A. platycheila (Fieber, 1844) in terms of its general habitus. However, based on a comparison between the type materials of the new species and the non-types and descriptions ( Péricart 1978, 1983) of A. carinata and A. platycheila , five main characteristics were recognized to easily differentiate A. alutacea sp. nov. from A. carinata and A. platycheila (Figs 1 A – D , 3 A – G , 7 A – G , 13 A – D ): posterior part of pronotal hood usually triangular (usually semicircular in A. platycheila ); lateral carinae absent or reduced, shorter than hood, without or with a single minute areola (developed, as long as hood, with a single row of areolae in A. carinata and A. platycheila ); calli smooth (rough in A. platycheila ); anterolateral angle of paranotum not or weakly protruding anteriorly, not reaching mid-level of compound eye (strongly protruding anteriorly, reaching mid-level of compound eye in A. carinata and A. platycheila ); and costal area of hemelytron with 2–3 rows of areolae in basal part, a single row in middle part, and 1–2 rows in apical part (with usually a single row throughout its length and sometimes 2 rows in basal part in A. platycheila ). Morphological differences between the new species and the eight other Japanese species besides A. carinata are presented in the identification key below.

Distribution.

Japan (Hokkaido) (Fig. 17 ) ( Nakatani 2016, 2018).

Etymology.

The species epithet is the Latin adjective “ alutaceus ”, referring to the pale brown body color.

Host plant.

Six individuals of Acalypta alutacea sp. nov. were collected from indeterminate mosses growing on the forest floor; at least one of these mosses could be a host plant for the new species.

Bionomics.

Acalypta alutacea sp. nov. inhabits the forest floor of deciduous broad-leaved forests in Hokkaido, which has a cool temperate climate.

Adults were collected in June and July ( Nakatani 2016, 2018) but nymphs were not collected.

Figures

Figure 1. Dorsal habitus of four Acalypta species from Japan. A A. alutacea sp. nov., brachypterous male B A. alutacea sp. nov., female C A. carinata, brachypterous male D A. carinata, brachypterous female E A. cooleyi, brachypterous male F A. cooleyi, macropterous male G A. gracilis, brachypterous male.

Figure 3. Pronota of four Acalypta species from Japan. A, B A. alutacea sp. nov., brachypterous males C, D A. alutacea sp. nov., brachypterous females E A. carinata, brachypterous male F, G A. carinata, brachypterous females H A. cooleyi, brachypterous male I A. cooleyi, macropterous male J A. gracilis, brachypterous male.

Figure 5. Rostra of six Acalypta species from Japan. A A. alutacea sp. nov. B A. carinata C A. cooleyi D A. gracilis E A. hirashimai F A. marginata.

Figure 7. Hemelytra of four Acalypta species from Japan. A, B A. alutacea sp. nov., brachypterous males C, D A. alutacea sp. nov., brachypterous females E A. carinata, brachypterous male F, G A. carinata, brachypterous females H A. cooleyi, brachypterous male I A. cooleyi, macropterous male J A. gracilis, brachypterous male.

Figure 9. Male terminalia of six Acalypta species from Japan. A A. alutacea sp. nov. B A. carinata C A. cooleyi D A. gracilis E A. hirashimai F A. marginata.

Figure 11. Female terminalia of six Acalypta species from Japan. A A. alutacea sp. nov. B A. carinata C A. cooleyi D A. gracilis E A. hirashimai F A. marginata.

Figure 13. Line drawings of pronota of two Acalypta species from Japan, dorsal view. A, B A. alutacea sp. nov. C, D A. carinata. Abbreviations: ca, calli; ho, hood; lc, lateral carina; mc, median carina; pa, paranotum; pd, pronotal disc; pp, posterior process.

Figure 14. Line drawings of male genitalia of A. alutacea sp. nov., dorsal view. A pygophore B paramere.

Figure 15. Living individuals of six Acalypta species from Japan. A A. alutacea sp. nov., brachypterous morph B, C A. carinata, brachypterous morphs D A. carinata, fifth instar nymph E A. cooleyi, brachypterous morph F A. cooleyi, macropterous morph G A. gracilis, brachypterous morph H A. hirashimai, brachypterous morph I A. marginata, brachypterous morph.

Figure 17. Collection sites of three Acalypta species from Japan used in present study.