Physatocheila nigrintegerrima, Souma, 2019

Souma, Jun, 2019, Physatocheila nigrintegerrima sp. nov. from Japan: a first fruit-feeder of the genus (Hemiptera: Heteroptera: Tingidae), Zootaxa 4638 (2), pp. 264-272 : 265-270

Physatocheila nigrintegerrima sp. nov.

( Fig. 1 A–D, 2A–E, 3A–B, 4A)

Type series. HOLOTYPE (macropterous ♂), JAPAN: Honshu : Niigata-ken , Nagaoka-shi , Suyoshi-machi, Magihanzogana-rindo, 253 m alt., 37.416139N 138.914694E, 20.v.2016, leg. G. Mashima ( TUA) . PARATYPES (macropterous 10 ♂♂ 8 ♀♀), JAPAN: Honshu: as holotype but 17.vii.2017 (4 ♂♂ 4 ♀♀, TUA) ; Iwate-ken, Ichinoseki-shi, Hanaizumi-cho , Wakutsu , 38.790889N 141.185083E, 25.vii.2018, leg. J. Souma (4 ♂♂ 3 ♀♀, TUA) ; Tochigi pref., Nikko , Chű-gű-shi, 3.vi.2014, leg. S. Maehara (1 ♀, TUA) ; Tochigi pref., Motegi, Mt. Kamakura , 22.iv.2015, leg. S. Maehara (1 ♂, TUA) ; S-Echigo, Noo , 27.iii.1983, leg. K. Baba (1 ♂, NSMT) .

Diagnosis. Recognized among other species of Physatocheila by a combination of the following characters: body approximately 3.7 mm long from head to apex of hemelytron ( Fig. 1 A–D); general color black; a pair of fron- tal spines on head reaching behind tip of tylus, touching each other at apices ( Fig. 2 A–B); median spine on head slightly reflexed upward, reaching level far remote from bases of frontal spines; a pair of occipital spines on head resting on vertex except apices, reaching middle of compound eyes; rostrum approximately 0.7 times as long as antennae, reaching anterior part of metasternum ( Fig. 2C ); lateral carinae of pronotum close to each other in anterior part, concealed by paranota at anterior end; each paranotum widened posteriorly, with 7 rows of areolae at widest part, approximately 2 times as long as its width; outer margin of paranotum gently curved outward throughout its length; and costal area of hemelytron slightly narrower than subcostal area at widest part of each, with 2 rows of areolae throughout its length.

Description. Macropterous, male. General color black; antennal segment III and tibiae dark brown; transverse fascia behind pronotal disk obscure; a pair of triangular spots on apical part of discoidal area fuscous; pubescence on body yellowish ( Fig. 1 A–B).

Body long-oval in shape, covered with minute pubescence, 2.5 times as long as maximum width across hemelytra ( Fig. 1A ). Head ( Fig. 2 A–C) stout, shorter than its maximum width across compound eyes, with five cephalic spines; a pair of frontal spines touching each other at apices, reaching behind tip of tylus; median spine shortest among cephalic spines, slightly reflexed upward, reaching level far remote from bases of frontal spines; a pair of occipital spines slightly curved inward, resting on vertex except apices, reaching middle of compound eyes; antenniferous tubercles obtuse, slightly curved inward; juga smooth on surface. Compound eyes prominent laterally, round in dorsal view. Antennae ( Fig. 1A ) smooth on surface; segments I close to each other at their base, approximately 2 times as long as its width; segment II cone-shaped, 1.4 times as long as its maximum width; segment III longest among antennal segments, 1.9 times as long as maximum width of head across compound eyes; segment IV fusiform, widest a little beyond middle, irregularly covered with long pubescence; ratios of lengths from segments I to IV as 1.3: 1.0: 6.8: 3.3. Bucculae short, approximately 3 times as long as their maximum height, touching each other at anterior ends, uneven, without distinct areolae. Rostrum approximately 0.7 times as long as antennae, reaching anterior part of metasternum.

Pronotum ( Fig. 1A ) strongly convex in anterior part, tricarinate, 1.6 times as long as maximum width across paranota. Pronotal disk coarsely punctate. Hood roof-shaped, lower than pronotum at highest part; anterior margin obtusely protruded forward, only concealing basal part of vertex. Pronotal carinae low, ridge-shaped, with a single row of minute areolae throughout their length; median carina straight, extending to apex of posterior process, lower than hood at maximum height; lateral carinae close to each other in apical part, concealed by paranota at anterior end, as high as median carina. Calli coarsely punctate. Paranotum reflexed, expanding inward, widened posteriorly, with 7 rows of areolae at widest part, approximately 2 times as long as its maximum width, incompletely covering pronotal disk in anterior part, not touching median carina, not bulged upward throughout its length, not forming a cyst; outer margin gently curved outward throughout its length, resting on pronotal disk throughout its length. Posterior process triangular, 0.8 times as wide as its length.

Hemelytron ( Fig. 1 A–B) narrow, 3.5 times as long as its maximum width, considerably extending beyond apex of abdomen; maximum width across hemelytra 1.2 times as much as maximum width across paranota; anterior margin gently curved outward; costal area distinct, slightly narrower than subcostal area at widest part of each, slightly reflexed upward in basal part, with 2 rows of areolae throughout its length; subcostal area subhorizontal, 0.3 times as wide as discoidal area at middle of hemelytron, with 3 rows of areolae throughout its length; discoidal area flat, distinctly expanding beyond middle of hemelytron, with 7 rows of areolae at widest part; sutural area well-developed, with 10 rows of areolae at widest part; boundary veins strongly carinate; hypocostal laminae as high as width of costal area at middle of hemelytron, with a single row of areolae throughout its length.

Thoracic pleura coarsely and evenly punctate ( Fig. 1B ). Ostioles well-developed, long-oval-shaped, not widened outward. Metasternum as wide as mesosternum. Sternal laminae nearly parallel to each other, apparently lower than bucculae, open in both anterior and posterior ends; mesosternal laminae as high as metasternal laminae. Legs smooth on surface; femora thickest at middle ( Fig. 1A ).

Abdomen ellipsoidal, 1.4 times as long as its maximum width; sternites IV to VIII each with a transverse furrow throughout their width. Pygophore ( Figs. 2D , 3A ) compressed dorsoventrally, hexagonal in dorsal view, strongly concave at anterior margin of dorsum, triangularly elevated at center of venter, smooth on surface, irregularly punc- tate in middle part of dorsum. Parameres ( Fig. 3 A–B) thick and long, strongly expanded in middle part, strongly curved inward in apical part; outer and inner margins covered with pubescence in middle part; suspensory arms of parameres completely visible in dorsal view.

Measurements (holotype). Body length with hemelytra 3.7 mm; maximum width across hemelytra 1.5 mm; pronotal width across paranota 1.2 mm.

Macropterous, female. General appearance very similar to that of male except for the following characters: abdomen with ovipositor at apical part ( Fig. 2E ); abdominal sternites IV to VII each with a transverse furrow throughout their width; ovipositor armed with well-developed ovivalvula at base; apical margin of abdomen round, weakly concave at apex.

Variations in both sexes (holotype and 18 paratypes). Body length from 3.7 to 3.8 mm; maximum width across hemelytra from 1.5 to 1.6 mm; pronotal width across paranota from 1.2 to 1.3 mm.

Brachypterous morph unknown in both sexes.

Remarks. Many Physatocheila species were diagnosed by several researchers based on the differences of the morphological characters such as the shape of the cephalic spines, the length of rostrum, the shape of the pronotal carinae, and the areolae of hemelytron (e.g. Osborn & Drake 1917; Drake 1942; China 1952; Golub 1977; Péricart 1983, etc.). These characters are also available and useful for the identification of the Japanese species. In addition, the width of the costal area of hemelytron relative to the subcostal area is also considered a good character for identification among at least the Japanese species.

Among other Japanese species of Physatocheila ( Fig. 5 A–E), this new species relates to P. distinguenda in the key provided by Yamada & Tomokuni (2012), and both species are very similar to each other in their morphological characters. However, based on a direct comparison of the type material of the new species with a number of specimens of P. distinguenda from Japan, the following characters are recognized to readily differentiate P. nigrintegerrima sp. nov. from P. distinguenda : general color black ( Fig. 1 A–D); a pair of frontal spines on head reaching behind tip of tylus ( Fig. 2 A–B); median spine on head reaching level far remote from bases of frontal spines; a pair of occipital spines on head reaching middle of compound eyes; rostrum reaching anterior part of metasternum ( Fig. 2C ); and costal area slightly narrower than subcostal area at widest part of each. On the other hand, P. distinguenda has the following features: general color brown ( Fig. 5A ); a pair of frontal spines on head reaching beyond tip of tylus; median spine on head reaching beyond bases of frontal spines; a pair of occipital spines on head reaching anterior margin of compound eyes; rostrum reaching posterior margin of abdominal sternite II; and costal area wider than subcostal area at widest part of each.

This new species resembles P. brevirostris Osborn & Drake, 1916 , P. major Osborn & Drake, 1917 , P. plexa (Say, 1832) and P. variegata Parshley, 1916 in general appearance, but is distinguished from them by the following characters: general color black ( Fig. 1 A–D); a pair of frontal spines on head reaching behind tip of tylus ( Fig. 2 A–B); median spine on head reaching level far remote from bases of frontal spines; a pair of occipital spines on head reaching middle of compound eyes; lateral carinae of pronotum close to each other in anterior part; and costal area slightly narrower than subcostal area at widest part of each.

Some previous records of P. distinguenda from Japan could correspond to this new species. At least, the photograph of the specimen provided by Nakano (2016) certainly shows this new species. However, P. distinguenda is undoubtedly distributed in Japan, being recorded by Takeya (1930, 1951), Maehara (2010), Yamada & Tomokuni (2012), and Yano (2014).

Distribution. Japan (eastern Honshu).

Etymology. The species epithet is the Latin adjective niger (meaning black) and integerrimus (meaning most entire), referring to the feature of a black body.

Host-plant. Japanese raisin tree, Hovenia dulcis Thunb. (Rhamnaceae) ( Fig. 4B ) was confirmed as a host-plant for the new species by Gô Mashima and me independently. This new species is the first documented species feeding on plants of the family Rhamnaceae in the genus Physatocheila , whereas host-plant of other congeners have been known to belong to various plants of 11 families such as Betulaceae , Cupressaceae , Ericaceae , Fagaceae , Juglandaceae , Oleaceae , Pinaceae , Rosaceae , Salicaceae , Sapindaceae , and Urticaceae (cf. Baba 1925; Takeya 1953; Drake & Ruhoff 1965a; Putshkov 1969, 1974; Golub 1977; Tomokuni 1979; Péricart 1983; Deckert & Göllner-Scheiding 2006; Rintala & Rinne 2011; Yamada & Tomokuni 2012; Maehara 2014).

An indeterminate tingid collected from H. dulcis by Hara (2004) may refer to this new species.

Biology. Most of the type specimens of this new species were collected from unripe fruits of the host tree, Hovenia dulcis in July by Gô Mashima and me independently, suggesting that it appears to feed on the fruits. Physatocheila nigrintegerrima sp. nov. is the first documented fruit-feeder of the genus. Some of the specimens were attracted by artificial light in May (Mashima pers. comm.) and were found on the edge of a lake shore in June (Maehara pers. comm.).

In Japan, an acanthosomatid bug, Acanthosoma firmatum (Walker, 1868) has also been known to feed on the fruits and peduncles of H. dulcis ( Hayashi 1987; Yasunaga et al. 2018). To the best of my knowledge, however, P. nigrintegerrima sp. nov. and A. firmatum have never been observed simultaneously. Thus, habitat segregation may occur between the two heteropterans.

Figures

FIGURE 1.A–D. Habitus images of dried specimens of Physatocheila nigrintegerrima sp. nov., dorsal and lateral views: macropterous male from Niigata, Honshu, Japan (A–B) and macropterous female from Iwate, Honshu, Japan (C–D). Scale bar: 1.0 mm.

FIGURE 2. A–E. Cephalic structures of Physatocheila nigrintegerrima sp. nov., dorsal, lateral, and ventral views (A–C). Abdominal end of P. nigrintegerrima sp. nov., ventral view: male (D) and female (E). Abbreviations: fs, frontal spine; ms, median spine; os, occipital spine; ov, ovivalvula. Scale bars: 0.2 mm.

FIGURE 3. A–B. Male terminalia of Physatocheila nigrintegerrima sp. nov., dorsal view: pygophore excluding pubescence on suspensory arms of parameres (A) and paramere (B). Scale bars: 0.1 mm.

FIGURE 4. A–B. Habitus image of a living female for Physatocheila nigrintegerrima sp. nov. (photograph taken indoors), from Iwate, Honshu, Japan (A). Host-plant (Hovenia dulcis Thunb.) of P. nigrintegerrima sp. nov. at Iwate, Honshu, Japan (B).

FIGURE 5. A–E. Five Physatocheila species from Japan: P. distinguenda (A); P. fieberi (B); P. miyatakei (C); P. orientis (D); P. veteris (E). Scale bar: 1.0 mm.