Neolygus autumnus, Yasunaga, 2024

Yasunaga, Tomohide, 2024, New species of the plant bug genus Neolygus Knight from Japan, Taiwan and Thailand (Hemiptera: Heteroptera: Miridae: Mirini), Zootaxa 5446 (4), pp. 451-487 : 454-462

publication ID

https://doi.org/ 10.11646/zootaxa.5446.4.1

publication LSID

lsid:zoobank.org:pub:C204C80E-332C-4537-A6BA-1FC372BD6783

DOI

https://doi.org/10.5281/zenodo.11121623

persistent identifier

https://treatment.plazi.org/id/6C640C52-B30B-FFBE-78AF-FF2BFA7FFD37

treatment provided by

Plazi

scientific name

Neolygus autumnus
status

sp. nov.

Neolygus autumnus n. sp.

Figs. 1A–B View FIGURE 1 , 4A–C View FIGURE 4 , 6A–F View FIGURE 6 , 13A–I View FIGURE 13 , 14A–F View FIGURE 14

Material examined. Holotype (♂). JAPAN: Kyushu, Miyazaki Pref., Takachiho Town, Gokasho-Kogen , Mt. Sobosan , 32.81, 131.27, 21 Sep 1994, S. Ide ( NWHS) ( AMNH _ PBI 00378765 About AMNH ) . Paratypes: JAPAN: Honshu : Kyoto Pref., Fukuchiyama City, Ooe Town, Senjogadake , Mt. Ooeyama , 35.46, 135.12, Hydrangea paniculata , 17 Sep 1984, M. Tomokuni ( NSMT) . Kyushu : same data as for holotype, 2♂ ( TYCN) ; Fukuoka Pref., Soeda Town, Mt. Hikosan , 33.4820, 130.9089, 27 Aug 1935, T. Esaki, 1♀ ( KUEC) GoogleMaps ; Kumamoto Pref., Izumi Village [= current Yatsushiro City, Izumi Town], Mt. Hakucho ( Shiratori ), 1200–1300 m alt., 32.480, 131.005, on flowers of Hydrangea paniculata , 6–7 Aug 1988, T. Yasunaga, 3♂ 2♀ ( TYCN) GoogleMaps ; same data, except for date 1 Aug 2003, 2♂ 3♀ ( TYCN) GoogleMaps ; Oita Pref., Takeda City, Mts. Kuju, Daisen-rindo (trail), 33.11, 131.26, on flowers of Hydrangea paniculata , 1 Aug 1988, Y. Abe, 3♂ 2♀ ( TYCN) . Shikoku : Ehime / Kochi Pref., Jiyoshi Pass , 900–1000 m alt. 33.4720, 132.9399, 6 Aug 1993, T. Yasunaga, 1♀ ( TYCN) GoogleMaps ; Ehime / Kochi Pref., Onogahara , 33.473, 132.885, 5 Aug 1993, T. Yasunaga, 1♂ ( TYCN) GoogleMaps ; Kochi Pref., Hongawa Village [= current ‘Ino Township’], Teragawa , 33.756, 133.168, 24 Jul 1996, T. Yasunaga, 1♂ 1♀ ( TYCN) GoogleMaps .

Diagnosis. Based on similar color pattern, genitalic structures and host association, this new species is most closely related to N. honshuensis (Linnavuori) , from which N. autumnus n. sp. can be distinguished by the following characters: Smaller size and shorter appendages ( Table 1 View TABLE 1 ); basic coloration relatively milky pale green in fresh specimens ( Fig. 1A–B View FIGURE 1 ); labium longer than metafemur; smaller peritreme on scent efferent system ( Fig. 13D View FIGURE 13 ); apical protuberances of both parameres weaker ( Figs. 6A–D View FIGURE 6 , 13N–O View FIGURE 13 ); vesical spiculum shorter, less curved apically and ventral sclerite narrower ( Figs. 6E View FIGURE 6 , 14A, D View FIGURE 14 ); posterior wall with narrower lateral lobe and spinules on interramal sclerite rather sparsely distributed ( Fig. 14B, E View FIGURE 14 ).

Description. Body oval, rather small in size ( Figs. 1A View FIGURE 1 , 4A–B View FIGURE 4 ); dorsum pale green, tinged with milky white in fresh specimens ( Fig. 1A View FIGURE 1 ), with uniformly distributed, pale, simple, reclining setae ( Fig. 13A–B View FIGURE 13 ); general coloration fading to brownish in dry-preserved specimens ( Fig. 4B–C View FIGURE 4 ). Head shining; vertex relatively narrow, with distinct basal transverse carina that is thicker than pronotal collar ( Fig. 13A View FIGURE 13 ); apex of clypeus always fuscous ( Fig. 1B View FIGURE 1 ). Antenna pale brown, in fresh specimens tinged with red; segments III and IV darker. Labium shiny pale brown, rather long, reaching or slightly exceeding apex of metacoxa ( Fig. 4C View FIGURE 4 ). Pronotum immaculate; scent efferent system creamy yellow, with narrow peritreme ( Fig. 13D View FIGURE 13 ); mesoscutum widely darkened. Hemelytral dark macula variable; clavus sometimes widely darkened ( Fig. 1A View FIGURE 1 , 4A View FIGURE 4 ); dark macula on apical part of corium usually small ( Fig. 4A–B View FIGURE 4 ) but widened in some specimens ( Fig. 1A View FIGURE 1 ); membrane pale smoky brown, with pale veins. All coxae and legs pale; apical part of metafemur usually with two brown rings; apex of each tarsomere III darkened; meta-tarsomere II slightly longer than III ( Fig. 13E View FIGURE 13 ); pretarsal structure as in Fig. 13F View FIGURE 13 . Ventral side of abdomen uniformly pale.

Male genitalia ( Figs. 6A–E View FIGURE 6 , 13G–I View FIGURE 13 , 14A, D View FIGURE 14 ): Parameres with rather small apical protuberances ( Fig. 6A–D View FIGURE 6 ); right paramere with rather short, sharply pointed hypophysis ( Fig. 6B, D View FIGURE 6 ); vesica with spiculum weakly curved apically and ventral sclerite rather narrow ( Figs. 6E View FIGURE 6 , 14A, D View FIGURE 14 ).

Female genitalia ( Figs. 6F View FIGURE 6 , 14B–C, E–F View FIGURE 14 ): Sclerotized rings thick-rimmed, elongate, mesially contiguous to each other ( Fig. 6F View FIGURE 6 ); posterior wall as in Fig. 14B, E View FIGURE 14 ; spinules on interramal sclerite rather sparsely distributed and restricted anteriad; lateral lobe rather narrow.

Measurements: See Table 1 View TABLE 1 .

Etymology. From Latin adjective, autumnus [= autumn], referring to emergence of this new species mainly from late summer to early autumn.

Distribution. Japan (SW. Honshu, Shikoku and Kyushu).

Biology. The breeding host was confirmed as Hydrangea paniculata Sieb. ( Hydrangeaceae ), on which teneral adults and late instar immature forms were observed. This new species ( Fig. 1A–B View FIGURE 1 ) and N. honshuensis (Linnavuori) ( Fig. 1C–D View FIGURE 1 ) were sometimes collected at same sites in southern Japan, but N. autumnus n. sp. (from late July to early October) emerges later than N. honshuensis (from mid-June to mid-August).

Remarks. Because of great similarity in external appearance, the present new species has in the past been regarded as a small variant or 2nd generation of its sibling, N. honshuensis (e.g. Yasunaga 1991b, 2001). However, subsequent observations revealed that the adults of both species coexisted in August. In addition, N. autumnus n. sp. is separable from N. honshuensis by the characters mentioned in above diagnosis. Speciation pattern of these sibling species may be derived from seasonal (allochronic) segregation.

The Japanese fauna of Neolygus is now revealed to include 39 valid species.As discussed above, several species are known only by the males (for most of the species, female specimens in all likelihood available but yet to be determined). Therefore, a definitive key to species is currently under construction and exact identification of many congeners is relied only upon observation of the male parameres and vesica (illustrations available in Kerzhner 1988; Yasunaga 1991a, b, 1992, 1999, 2001, 2023; Yasunaga & Schwartz 2005; Yamamoto & Yasunaga 2020; Noguchi et al. 2023).

As a key to Japanese species provided by Yasunaga (1992) is no longer usable, however, I herein suggest the following key that would aid in identification of species or approximate grouping. The present key is constructed principally for male specimens (species shown in couplets 1–4 applicable to both sexes). For unequivocal identification of the species appearing in couplets 19–24, observation (or dissection) of the genitalia is required († species currently represented only by male): † N. angustivertex (for figures of male genitalia, cf. Yasunaga 2023), † N. chichibumontis n. sp. ( Fig. 7A–D View FIGURE 7 ), N. flavoviridis (cf. Yasunaga 1991c), N. hoberlandti ( Yasunaga 1991b, 2023), † N. kawasawai (Yasunaga 2023) , N. makiharai ( Yasunaga 1992) , † N. nozakii ( Fig. 7E–F View FIGURE 7 ; Yasunaga 2023), † N. tomokunii ( Yasunaga 1991c) and N. lobatus (immaculate variant, Fig. 3D View FIGURE 3 ; Yasunaga 1991b).

1. Dorsum widely fuscous, reddish or yellow-orange, lacking greenish tinge......................................... 2

- Basic coloration on dorsum greenish (or fading to pale brown in dry-preserved specimens)........................... 4

2. Body ovoid; hemelytron widely orange-scarlet with dark maculae posteriad................................. N. roseus View in CoL

- Body elongate ovoid; hemelytron almost uniformly fuscous (only cuneus sometimes reddish)......................... 3

3. Antennomeres I and II dark brown; femora usually dark brown, without reddish tinge......................... N. ryoma View in CoL

- Antennomeres I and II pale brown; femora red or orange-brown...................................... N. miyamotoi View in CoL

4. Antennomere I usually fuscous; vernal species restricted to a hackberry, Celtis sinensis View in CoL ....................... N. tosanus

- Antennal segment I always pale brown (pale green or yellowish green in fresh specimens)........................... 5

5. Male antennomere III as long as or longer than basal width of pronotum; male metatibia> 4 mm [if male antennomere III long enough, then metatibia <3.8 mm (= N. nakatanii View in CoL , part)]....................................................... 6

- Male antennomere III obviously shorter than basal width of pronotum; male metatibia <3.8 mm ...................... 7

6. Body elongate, slender, subparallel-sided; base of antennomere II with a dark annulation ( Fig. 3M View FIGURE 3 ); labium longer, surpassing apex of mesocoxa; pronotal disk and apical part of corium with dark maculae or spots; associated mainly with alders, Alnus spp. ( Betulaceae View in CoL ).............................................................................. N. longiusculus View in CoL

- Body elongate oval; basal part of antennomere II pale brown, not darkened; labium shorter, not exceeding apex of mesocoxa; pronotum and corium almost immaculate (apex of corium narrowly or faintly darkened); restricted to Araliaceae View in CoL broadleaf trees, Chengiopanax sciadophylloides View in CoL and Eleutherococcus senticosus View in CoL ................................. N. majusculus View in CoL

7. Smallest species in Japan, with body length 3.9–4.3 mm [color pattern variable ( Fig. 3E–F View FIGURE 3 ); if body length <4.5 mm and dorsum uniformly pale, then antennomere II shorter than labium = N. makiharai View in CoL (part)]...................... N. pteleinus View in CoL

- Body longer than 4.5 mm (mostly> 4.8 mm)............................................................... 8

8. Dorsum usually tinged with white or ivory; pronotum with a pair of dark spots on disk.............................. 9

- Dorsum green, pale green, or yellowish green, not tinged with white (but sometimes with orange tinge); pronotum sometimes widely darkened or with dark maculae which, however, are not forming clear paired spots.......................... 10

9. Body oval; antennomere IV longer than I; paired dark spots on pronotum narrow, rectangular; restricted to silverberries, Elaegnus broadleaf trees ( Rosaceae View in CoL )............................................................... N. elaegni View in CoL

- Body elongate oval; antennomere IV shorter than I; pronotum with a pair of dark, semi-circular or triangular spots on disk; associated with a walnut, Juglans mandshurica View in CoL ( Juglandaceae View in CoL )........................... N. juglandis View in CoL [part ( Fig. 3K View FIGURE 3 )]

10. Body ovoid, relatively stout (cf. Fig. 3J View FIGURE 3 ); clypeus entirely pale, without darkened apex; male antennomere II as long as or shorter than basal width of pronotum..................................................................... 11

- Body elongate-oval or elongate; if body ovoid and rather stout, then apical part of clypeus infuscate; male antennomere II longer than basal width of pronotum..................................................................... 13

11. Dorsum widely pale green; apex of corium narrowly darkened; currently known only from Kyushu............. N. obesus View in CoL

- Clavus and apical (more than 1/4) part of corium dark brown; northern Japan..................................... 12

12. Dorsum yellowish green; apical dark macula on corium rather squared..................................... N. acelis

- Dorsum tinged with pale orange; dark macula on corium triangular or semi-circular.......................... N. ichitai View in CoL

13. Dorsum almost uniformly pale green or yellowish green as in Fig. 3A–B View FIGURE 3 [fading to pale or stramineous brown in dry-preserved specimens ( Fig. 4G–H View FIGURE 4 )]; only apex of clypeus darkened in some species........................................ 14

- Dorsum somewhere (particularly on apex or apical part of corium) with dark spots and/or maculae.................... 25

14. Apex or apical part of clypeus infuscate.................................................................. 15

- Clypeus entirely pale, not darkened...................................................................... 18

15. Body larger (basal width of male pronotum> 2 mm)..................................... N. juglandis View in CoL (pale variant)

- Body smaller (basal width of male pronotum <1.8 mm)...................................................... 16

16. Labium as long as or longer than metafemur......................... N. lobatus View in CoL (pale variant with dark apex of clypeus)

- Labium shorter than metafemur......................................................................... 17

17. Male vertex wider, 0.33–0.35 times as wide as head width across eyes in dorsal view.............. N. hasegawai ( Fig. 4I View FIGURE 4 )

- Male vertex narrower, less than 0.29 times as wide as head width including eyes....................... N. tiliicola View in CoL [part]

18. Vertex very narrow, 0.20 times as wide as head width across eyes in dorsal view........................ N. yamatoensis View in CoL

- Vertex ≥ 0.22 times as wide as head width across eyes....................................................... 19

19. Antennomere III more than 1.4 times as long as head width across eyes, about as long as basal width of pronotum................................................................................................... N. nakatanii View in CoL

- Antennomere III less than 1.3 times as long as head width across eyes, shorter than basal width of pronotum............ 20

20. Antennomere II shorter than labium or metafemur.................................................. N. makiharai View in CoL

- Antennomere II usually longer than labium or metafemur.................................................... 21

21. Length of antennomere II shorter than twice of head width across eyes; antennomere III shorter than head width across eyes................... N. flavoviridis View in CoL ( Fig. 3A View FIGURE 3 ), N. lobatus View in CoL (pale variant, Fig. 3D View FIGURE 3 ), N. nozakii [part], N. tomokunii View in CoL or N. zhugei View in CoL

- Length of antennomere II greater than twice of head width across eyes; antennomere III longer than head width across eyes22

22. Antennomere II longer than twice length of I.............................................................. 23

- Antennomere II shorter than twice length of I.............................................................. 24

23. Vertex wider than an eye in dorsal view.......................................................... N. kawasawai View in CoL

- Vertex narrower than an eye in dorsal view..................................................... N. angustivertex

24. Male genitalia as in Fig. 7A–D......................................................... N View FIGURE 7 . chichibumontis n. sp.

- Male genitalia as in Fig. 7E–F.................................................................... N View FIGURE 7 . nozakii

25. Pronotal disk widely dark brown or reddish brown ( Fig. 3C, E, G, I View FIGURE 3 )............................................ 26

- Pronotum pale, almost immaculate (e.g., Fig. 3A View FIGURE 3 ), or posterior part narrowly darkened (e.g., Fig. 3H View FIGURE 3 )................. 28

26. Antennomere III as long as or shorter than head width across eyes.................... N. lobatus View in CoL (dark variant, Fig. 3C View FIGURE 3 )

- Antennomere III obviously longer than head width across eyes................................................ 27

27. Vertex wider, 0.35–0.42 times as wide as head width across eyes in dorsal view ( Fig. 3I View FIGURE 3 )....................... N. esakii View in CoL

- Vertex narrower, 0.32–0.33 times as wide as head width across eyes................ N. nipponicus View in CoL (dark variant, Fig. 3G View FIGURE 3 )

28. Pronotum narrowly (less than posterior half) darkened along posterior margin (cf. Fig. 3H View FIGURE 3 ).......................... 29

- Pronotum uniformly pale, immaculate.................................................................... 30

29. Body smaller, less than 5 mm; labium as long as basal width of pronotum; scutellum castaneous ( Fig. 5A View FIGURE 5 ); currently known only from Okinawa Island of the Ryukyus..................................................... N. yonanus n. sp.

- Body longer than 5.5 mm; labium longer than basal width of pronotum; scutellum pale; cryophilic species associated with deciduous broadleaf trees or shrubs in Hokkaido and Honshu (north of Kanto area) [some specimens (with posteriorly darkened pronotum) of N. honshuensis View in CoL may run to this couplet, but its labium is as long as or shorter than basal width of pronotum]............................................................................................ N. nipponicus View in CoL

30. Length of antennomere II nearly equal to twice as long as III; membrane with noticeable brown spots ( Fig. 3N View FIGURE 3 ); associated with alders, birches and willows in north of central Honshu............................................... N. nemoralis View in CoL

- Antennomere II obviously shorter than twice length of III; membrane with less spotted pattern....................... 31

31. Apex of clypeus narrowly or faintly darkened, or entirely pale................................................. 32

- More than apical 1/5 of clypeus clearly darkened........................................................... 36

32. Body length less than 5.2 mm; antennomere II as long as or shorter than labium................................... 33

- Body longer than 5.4 mm; antennomere II obviously longer than labium......................................... 34

33. Metafemur as long as antennomere II; restricted to Hokkaido (currently known from urbanized zone of Sapporo area) and associated with Tilia spp. ......................................................................... N. vityazi View in CoL

- Metafemur longer than antennomere II; Hydrangea panuculata in western Japan................ N. autumnus n. sp. [part]

34. Clavus usually more or less darkened; apical part of corium with noticeable fuscous, ovoid or semi-circular macula ( Fig. 1C View FIGURE 1 ); most commonly found among Japanese congeners................................................ N. honshuensis View in CoL

- Clavus always pale; apical part of corium with brown, narrow macula or small spot ( Fig. 1A, C View FIGURE 1 ); distribution restricted... 35

35. Antennomere II longer than metafemur; apex of corium with a small, dark, circular or semicircular spot; currently known only from central Hokkaido and associated with Syringa reticulata View in CoL .......................................... N. flaviceps View in CoL

- Antennomere II as long as metafemur; apex of corium narrowly darkened ( Fig. 3L View FIGURE 3 ; often faintly brown in dry-preserved specimens); associated with a horse-chestnut, Aesculus turbinata View in CoL in southwestern Japan....................... N. similis View in CoL

36. Antennomere II as long as or longer than metafemur............................................. N. tiliicola View in CoL [part]

- Antennomere II shorter than metafemur.................................................................. 37

37. Apical fuscous macula on corium relatively large and clear (cf. Figs. IE, 4D)..................................... 38

- Apex of corium narrowly and/or faintly darkened (cf. Fig. 2A, E, G View FIGURE 2 )............................................ 39

38. Vertex narrower, 0.22 (0.33–0.34 in female) times as wide as head width across eyes; currently know only from warm temperate Goto Islands in Nagasaki Prefecture ..................................................... N. chikanoshima n. sp.

- Vertex wider, 0.30–0.33 (0.34–0.37 in female) times as wide as head width across eyes; associated with blackbelly, Morus australis View in CoL , in temperate and cold temperate deciduous forest zones................................... N. hakusanensis View in CoL

39. Antennomere II as long as basal width of pronotum; restricted to Ryukyu Islands and known to associated with flower-buds and inflorescence of a broadleaf, Trema orientalis View in CoL ( Cannabaceae View in CoL )................................ N. tokaraensis View in CoL ( Fig. 2G View FIGURE 2 )

- Antennomere II obviously longer than basal width of pronotum................................................ 40

40. Dorsum usually tinged with olive-orange and metafemur sometimes reddish in fresh (or live) individuals; antennomere II more than 3 times as long as IV; thermophilic species propagating mainly on an evergreen Fagaceae View in CoL broadleaf, Castanopsis sieboldii View in CoL in warm temperate and subtropical climatic zones of southwestern Japan including the Ryukyu Islands...... N. kyushuensis View in CoL

- Dorsum and metafemur pale green or yellowish green in fresh specimens; antennomere II less than 3 times as long as IV; inhabiting deciduous forests in temperate and cold temperate zones....................................... N. tiliicola View in CoL

AMNH

American Museum of Natural History

NSMT

National Science Museum (Natural History)

KUEC

Kyushu University Entomology Collection

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Hemiptera

Family

Miridae

Genus

Neolygus

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