Sadoletus melasmus, Ban, 2018

Ban, Teruaki, 2018, The lygaeoid bug family Heterogastridae (Hemiptera: Heteroptera: Lygaeoidea) from Laos and Thailand, with descriptions of three new species, Zootaxa 4446 (1), pp. 51-67 : 57-60

Sadoletus melasmus sp. nov.

( Figs. 8–9 , 15 , 18 , 25–29 )

Type Materials. Holotype: ♀, THAILAND: 12°40'14“–30“N, 101°24'50“–52”E, alt. 452–552 m, Near Rayong, Rayong Prov., 17.III.2015, Teruaki Ban (TUA) . Paratypes: THAILAND: 1 ♂ 2 ♀, 12°49'14.5“N, 102°07'40.6”E, alt. 66 m, Krathing Country Resort, Chanthaburi Prov., 14.III.2015, Teruaki Ban (TUA) ; 1 ♂ 2 ♀, same locality, 15.III.2015, Teruaki Ban (TUA).

Diagnosis. Recognized among congeners of Sadoletus by the following characters: Head, anterior lobe of pronotum, basal half of scutellum and apical third of corium black ( Figs. 8, 9 ); labium exceeding posterior margin of prothorax ( Fig. 15 ); posterior lobe of pronotum pale yellow, with submedian longitudinal band and 2 dark brown spots at lateral angle ( Figs. 8, 9 ); corium white in basal two-thirds and blackened in apical third, with black spots around inner angle of corium and claval commissure ( Figs. 8, 9 ); clavus white; femora and tibiae yellow and white, with brown or yellow annulations, metafemur and metatibia with brown annulations ( Figs. 8, 9 ); abdominal sternum black; ovipositor strongly curved laterally ( Fig. 18 ); posterior margin of pygophore and cuplike sclerite fused together ( Fig. 25 ); paramere sickle-shaped at apex ( Fig. 26 ).

Description. Female (holotype): Venter almost black. Short decumbent setae on body silvery. Punctures on pronotum, scutellum, and corium dark brown. Head ( Fig. 9 ) black. Clypeus pale yellow. Antenna generally brownish yellow, apical three quarters of segment IV tinged with dark brown. Labium dark brown; segment III and basal three quarters of segment IV brownish yellow. Pronotum ( Fig. 9 ) black in anterior lobe and pale brownish yellow in posterior lobe, posterior lobe with longitudinal pale stripe along meson and 2 dark brown longitudinal band and 2 dark brown markings at around lateral angle. Venter of mesothorax and metathorax black; peritreme brown. Scutellum ( Fig. 9 ) black in basal half and brown in apical half. Apical half of scutellum with pale longitudinal stripe along meson. Corium ( Fig. 9 ) white in basal two-thirds and black in remaining part; black circular spot at inner angle; clavus white, with longitudinal black stripe along claval commissure; hemelytral membrane hyaline, with oval brownish spot at middle. Coxae dark brown; trochanters, femora and tibiae pale yellow; metafemur and metatibia with brown annulations; tarsomere I pale yellow, tarsomeres II and III pale brown. Abdomen ( Fig. 15 ) black; each laterotergite entirely reddish brown.

Body ( Fig. 9 ) 3.1 times as long as width across humeri. Head ( Fig. 9 ) 1.7 times as wide as its length, covered with both rough and fine punctures; tylus tumid upwards; clypeus weakly projecting anteriad; juga with decumbent setae. Eyes occupying nearly half area of head in lateral view, not reaching anterior margin of pronotum. Antennae covered with suberect setae; proportional lengths of segments I to IV 1.0: 1.7: 1.6: 2.4. Labium slightly exceeding posterior margin of prothorax, not reaching mesocoxae; proportional lengths of segments I to IV 1.4: 1.4: 1.1: 1.0.

Pronotum ( Fig. 9 ) a little more than 1.4 times as wide as its length, nearly trapezoidal, lacking collar, covered with dense punctures, and with lateral margin of anterior lobe weakly serrate; posterior lobe 1.4 times as long as anterior lobe, slightly more convex than anterior lobe; posterior margin almost straight. Venter of prothorax, mesepisterna and metepisterna covered with decumbent setae. Scutellum ( Fig. 9 ) triangular, weakly tumid transversely in basal half, covered with long suberect setae. Hemelytra ( Fig. 9 ) exceeding apex of abdomen; apical margin of corium as long as claval suture. Profemur moderately expanded, armed with a spine ventrally at about apical third; tibiae and tarsi sparsely covered with long erect setae.

Abdomen wider than hemelytral width; sternum covered with decumbent setae. Ovipositor ( Fig. 18 ) strongly curved laterally, reaching posterior margin of sternite VI, approximate oviposital length 0.4 mm; the two hemiventrites of the medially completely bisected sternite VII are short, therefore posterior margins of sternites III–V straight, posterior margin of sternite VI weakly sinuate ( Fig. 18 ).

Spermatheca (paratypes) as in Fig. 29 .

Male (paratypes): Male resembles female in general appearance. Body ( Fig. 8 ) evidently narrower; coloration of posterior lobe of pronotum and each leg paler than female; pygophore ( Fig. 25 ) nearly spherical in dorsal view, covered with suberect setae; dorsal sinus of posterior aperture one quarter as wide at middle as pygophore, without collar along anterior margin; posterior margin of pygophore and cuplike sclerite fused together; paramere ( Fig. 26 ) robust, twisted at basal third, sickle-shaped at apex, covered with several erect setae, sensory processes projecting laterally; phallosoma ( Figs. 27, 28 ) nearly twice as long as its width in ventral view, wrinkled at apical margin.

Measurements [♂ (n=2) / ♀ (n=5), value for holotype female in parentheses]. Body length 4.55–4.6 / 4.61– 5.2 (4.97); body height between coxae and dorsum 1.15–1.2 / 1.18–1.38 (1.3); head length 0.7–0.75 / 0.7–0.83 (0.75), head width across eyes 1.25–1.3 / 1.23–1.38 (1.31); length of antennal segments I–IV respectively 0.33– 0.34 / 0.31–0.35 (0.34), 0.59–0.63 / 0.52–0.65 (0.58), 0.58–0.59 / 0.5–0.6 (0.53), 0.85–0.86 / 0.76–0.88 (0.81); length of rostral segments I–IV respectively 0.41–0.43 / 0.41–0.43 (0.42), 0.43–0.44 / 0.44–0.45 (0.44), 0.33–0.35 / 0.31–0.35 (0.35), 0.3–0.31 / 0.29–0.33 (0.31); mesal pronotal length 1.08–1.13 / 1.06–1.31 (1.18); posterior pronotal width 1.38–1.4 / 1.41–1.73 (1.59); mesal scutellal length 0.74–0.76 / 0.76–0.96 (0.81); basal scutellal width 0.74–0.78 / 0.76–1.0 (0.88); hemelytral length 2.85–2.9 / 2.96–3.38 (3.25); maximum width across hemelytra 1.35–1.43 / 1.44–1.73 (1.53).

Distribution. Thailand (Chanthaburi Prov., Rayong Prov.).

Etymology. The species epithet is the Greek adjective “ melasmus ” (meaning black spot) referring to characteristic black to dark brown spot at inner angle of corium.

Remarks. This new species is most similar in general appearance to S. bakeri Bergroth , S. montanellus Bergroth and S. ryukyuensis Ban et Ishikawa, but it can be distinguished from the latter by a combination of the following characters: Body length more than 4.5 mm (in S. montanellus , 3.0 mm); antennal segment II less than twice as long as segment I (vs. antennal segment II more than twice as long as segment I); labium slightly exceeding posterior margin of prothorax, not reaching mesocoxae (vs. at least reaching mesocoxae); posterior lobe of pronotum pale brownish yellow (in S. montanellus , dark brown); coxae black (in S. ryukyuensis , coxae brown); ground color of femora and tibiae pale yellow (vs. femora and tibiae yellowish brown); apical third of corium black in both sexes (in S. ryukyuensis , apical third of corium white in female); hemelytra with dark markings at inner angle of corium and hemelytral membrane (vs. hemelytra lacking dark marking at inner angle of corium and hemelytral membrane); abdominal sterna black (in S. bakeri abdominal sterna reddish brown).

Biological notes. The specimens were collected from trees of Ficus sp. in mountainous forests and the open forest adjacent to a resort hotel, with several other heterogastrid and rhyparochromid species.

Figures

FIGURES 6–9. Habitus of Heterogastridae species from Laos and Thailand. 6–7, Sadoletus laosensis sp. nov., male (6), holotype, female (7); 8–9, S. melasmus sp. nov., male (8), holotype, female (9). Scales: 1.0 mm.

FIGURES 14–16. Females of each new Sadoletus species, ventral view. 14, Sadoletus laosensis sp. nov.; 15, S. melasmus sp. nov.; 16, S. subpellucidus sp. nov. Scales: 1.0 mm.

FIGURES 17–19. Abdominal sternite VI and ovipositer of each new Sadoletus species, ventral view. 17, Sadoletus laosensis sp. nov.; 18, S. melasmus sp. nov.; 19, S. subpellucidus sp. nov. Scales: 1.0 mm.

FIGURES 25–29. Sadoletus melasmus sp. nov. 25, Pygophore, dorsal view (setae omitted from left half); 26, left paramere, dorsal view; 27–28, phallus (endosoma not everted), ventral (27) and lateral (28) views; 29, spermatheca. Scales: 0.1 mm.