Phytoliriomyza nigroflava Kato, 2022

Kato, Makoto, Yamamori, Luna & Imada, Yume, 2022, Diversity underfoot of agromyzids (Agromyzidae, Diptera) mining thalli of liverworts and hornworts, ZooKeys 1133, pp. 1-164 : 1

24. Phytoliriomyza nigroflava Kato sp. nov.

Fig. 46 , 47

Material examined.

Holotype: Japan: 1♂ (MK-AG-a300), Yuni-ishikari-gawa, Soun-kyo, Kamikawa, Hokkaido (43.640°N, 143.048°E, 820 m asl), 31-V-2021 (as larva), emerged on 3-VII-2021, NSMT-I-Dip 32031. Paratypes: Japan: 1♂1♀ (MK-AG-a467, a22), Yuni-ishikari-gawa, Soun-kyo, Kamikawa, Hokkaido, 1-VI-2020 (as larva), emerged on 8-12-VII-2020, NSMT-I-Dip 32032, 32033; 2♂ (MK-AG- a301, a468), Shirabiso-toge, Kamimura, Iida, Nagano Pref., 17-IV-2021 (as larva), emerged on 22-V-2021, NSMT-I-Dip 32034, 32035; 1♂1♀ (MK-AG-a469, a302), Sarukura, Hakuba, Nagano Pref., 11-V-2021 (as larva), emerged on 21-24-VI-2021, NSMT-I-Dip 32036, 32037.

Other material.

Japan: 7♂12♀, Soun-kyo, Kamikawa, Hokkaido, 31-V-2021 (as larva), emerged on 11-22-VII-2021; 2♂4♀, Aizankei, Kamikawa, Hokkaido, 4-X-2011 (as larva), emerged on 26-V-2-VI-2011; 2♂6♀, Yuni-ishikari-gawa, Soun-kyo, Kamikawa, Hokkaido, 1-VI-2020 (as larva), emerged on 5-14-VII-2020; 10♂4♀, Nozuka-toge, Urakawa, Hokkaido, 30-IV-2011 (as larva), emerged on 5-18-VI-2021; 1♂2♀, Mt. Tengu, Jozan-kei, Minami-ku, Sapporo, Hokkaido, 2-V-2021 (as larva), emerged on 7-10-VI-2021; 2♂1♀, Jozan-kei, Minami-ku, Sapporo, Hokkaido, 2-V-2021 (as larva), emerged on 7-19-VI-2021; 1♂, Horoman-kyo, Samani, Hokkaido, 30-IV-2021 (as larva), emerged on 19-VI-2021.

Diagnosis.

A medium-sized yellow species (wing length 2.2-2.3 mm) uniquely having sexual dimorphism in color of the 1st flagellomere: male yellow, female black. The adult has a pruinose yellow scutum with a medial and two pairs of black stripes, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-laterally with a long tubercle-like seta, and inner-basally with a comb comprising 6-8 long fused tubercle-like setae. Larva mines the thallus of Conocephalum salebrosum .

Description.

Adult male (Fig. 46A-C ).

Head: Head yellow, with ocellar tubercle pale brown and back of head dark brown excluding margins (Fig. 46C ). Antenna porrect, first flagellomere yellow, pedicel and scape brown (Fig. 46A ). Arista subbasal, black, pubescent. Clypeus, face, gena, parafacial and postgena yellow (Fig. 46C ). Proboscis normal, yellow; palpus yellow, cylindrical (Fig. 46C ). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 46B ). Orbital setulae minute and erect, in a single row.

Thorax: Thorax subshiny. Scutum yellow with medial black stripe on anterior 2/3, with a pair of narrow black supra-alar stripes and a pair of wider black intra-alar stripes, which adjoin a pair of lateral presutural black ovoid spots (Fig. 46B ). Scutellum and subscutellum yellow. Mediotergite brown, katatergite yellow, and anatergite yellow with venter brown (Fig. 46A ). Pleuron yellow with postpronotal lobe faintly brown anteriorly, venter of katepisternum and meron brown (Fig. 46A ). Haltere yellow. Calypter margin and hairs gray. Leg segments entirely yellow; tibia and tarsus darker (Fig. 46A ). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 46B ). Acrostichal setulae 8-10 pairs in two irregular rows. Wing: Wing length 2.2 mm, costa reaching M1 (Fig. 46A ). Length of ultimate section of vein M4 divided by penultimate section 1.1-1.2.

Abdomen: Abdomen dorsally subshiny yellow; epandrium brown (Fig. 46A ). Genitalia: (Fig. 46H-L ) Epandrium rounded apically; inner-lateral surface with a long tubercle-like seta; inner-anterior surface with a comb comprising 6-8 fused long tubercle-like setae and an irregular row of several (2-4) small tubercle-like setae immediately outward from the comb (Fig. 46I ). Surstylus rounded, directed inwards, setose apically, with one (rarely 2) long tubercle-like seta on posterior margin (Fig. 46I ). Cercus narrow, setose. Subepandrial sclerite V-shaped in posterior view; dorsal lobe with one seta (Fig. 46I ). Hypandrium slightly sclerotized along outer margin (Fig. 46H ). Postgonite bare, goose barnacle-shaped, pointed and cleft apically (Fig. 46L ). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 46H ). Basiphallus with pale broad lateral plate on left side and lightly sclerotized dorsal margin (Fig. 46H ). Hypophallus hood-shaped, membranous; lateral margins lightly sclerotized; medially with a pair of dark fused sclerites incurved ventrally, which have small lateral transparent wings (Fig. 46H, I ). Mesophallus dark, cylindrical, widest basally, as long as distiphallus (Fig. 46I ). Distiphallus comprising one pair of stout tubules; basal half composed of ventral dark subtriangular sclerite and weaker medial region; distal half cylindrical, dorsally pigmented, constricted subdistally; with truncated, unpigmented apex (Fig. 46I ). Ejaculatory apodeme pale brown, with hammerhead-shaped blade and broad stalk; base wide to one side; sperm pump clear (Fig. 46K ).

Female (Fig. 46D-G ). Similar to male, but larger, first flagellomere black with yellowish base; pedicel and scape yellow (Fig. 46F ). Wing length 2.32 mm. Postabdomen: (Fig. 47A, B ) Oviscape dark brown, setigerous (Fig. 47A ). Tergite 10 trifurcate, laterally uniting narrow pleural sclerites (Fig. 47B ). Each cercus with two stout, apical, trichoid sensilla, 1/3 length of cercus (Fig. 47B ). Spermathecae semi-orbicular, with truncate proximal ends (Fig. 47A ).

Variation.

The color of the lateral stripes on the scutum varies among populations, with specimens in the southern population having darker stripes. The number of tubercle-like setae in a comb in male genitalia varies from 5 to 7 among localities.

Etymology.

The specific name (nigra = black, flava = yellow) refers to heterosexually different colors of flagellomere: precisely, the male and female of this species have a yellow and a black flagellomere, respectively.

Japanese name.

Murasame-jagoke-hamoguribae.

Host plants.

Conocephalum salebrosum and C. purpureorubrum ( Conocephalaceae ).

Mine.

Larvae construct linear mines in the thallus in early instars, later entering the midrib, and pupate in the mines (Fig. 47E-H ).

Biological notes.

The habitats of this species are mesic slopes in subalpine coniferous forests dominated by Abies spp., Picea spp. And Betula spp. (Fig. 47C, D ). Our rearing records suggest that this species is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Hokkaido, Honshu (Fig. 45 ). The distribution is restricted in cool-temperate subalpine forests in high altitudes.

Remarks.

This species is unique in that male and female respectively has yellow and black 1st flagellomere of antenna; intersexual color dimorphism in 1st flagellomere was observed only in this species among the studied species. This species resembles P. brunofasciata and P. pallidofasciata in having two pairs of dark lateral stripes on scutum and similar genitalia; it is distinguished from them by the color of the two pairs of dark lateral stripes (black in P. nigroflava ; brown in P. brunofasciata ; pale brown in P. pallidofasciata ). It also resembles P. bifasciata in having black stripes on scutum; it is distinguished from the latter by the morphology of surstylus of male genitalia (rounded in P. nigroflava ; elongated in P. bifasciata ) and the number of the black stripes (two pairs in P. nigroflava ; one pair in P. bifasciata ).

Figures

Figure 45. Locality records of three Phytoliriomyza species associated with Conocephalum spp.: P. caliginosa, P. ugetsu, P. nigroflava and P. brunofasciata.

Figure 46. Phytoliriomyza nigroflava sp. nov. A-C holotype male A habitus B dorsal C frontal D-G paratype female (MK-AG-a 22) D habitus E dorsal F frontal G posterior H-K male genitalia H whole genitalia, ventral I epandrium, ventral J phallic complex, lateral K ejaculatory apodeme, lateral B postgonite.

Figure 47. Female morphology and larval ecology of Phytoliriomyza nigroflava sp. nov. A, B female postabdomen A oviscape and spermatheca B tergite 10 C, D habitat (C type locality D at Shirabiso-toge) E-H mined thalli of Conocephalum salebrosum at type locality. Arrows in G and H shows internal puparia.