Phytoliriomyza tsukuyomi 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

3. Phytoliriomyza tsukuyomi Kato sp. nov.

Fig. 5

Material examined.

Holotype: Japan: 1♂ (MK-AG-a397), Matsubara-ko, Koumi, Nagano Pref. (36.053896°N, 138.461847°E, 1110 m asl), 12-V-2021 (as larva), emerged on 18-VI-2021, NSMT-I-Dip 31897. Paratypes: Japan: 1♂1♀ (MK-AG-a455, a443), same data as holotype, emerged on 17-22-VI-2021, NSMT-I-Dip 31898, 31899; 1♂1♀ (MK-AG-a521, a528), Ikawa-toge, Aoi-ku, Shisuoka Pref., 26-V-2021 (as larva), emerged on 31-V-2-VI-2021, NSMT-I-Dip 31900, 31901; 1♂ (MK-AG-a577), Tokuzo-ji, Yana, Kisarazu, Chiba Pref., 1-XI-2021 (as larva), emerged on 3-XII-2021, NSMT-I-Dip 31902.

Other material.

Japan: 1♂1♀, Ikawa-toge, Aoi-ku, Shizuoka Pref., 26-V-2021 (as larva), emerged on 31-V-2-VI-2021; 1♂, Tokuzo-ji, Yana, Kisarazu, Chiba Pref., I-XI-2021 (as larva), emerged on 3-XII-2021.

Diagnosis.

A medium-sized species (wing length 1.6-1.7 mm) having pruinose dark gray scutum, light yellow scutellum, black 1st flagellomere, dark maxillary palpus, dark halteres, and dark legs. Male epandrium inner-basally with a comb of four unfused tubercle-like setae, and inner-laterally with a comb of three or four fused, long, tubercle-like setae; surstylus bilobed and hypertrophied dorsal arm with one tubercle-like seta. Larva mines the thallus of Marchantia polymorpha .

Description.

Adult male (Fig. 5A-E ).

Head: Head light yellow, with ocellar tubercle brown, frons light yellow, back of head dark brown (Fig. 5C ). Antenna porrect, first flagellomere black, pedicel and scape light yellow. Arista subbasal, black, pubescent. Clypeus, face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus brownish gray, cylindrical. Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 5D ). Orbital setulae minute and erect, in a single row.

Thorax: Thorax pruinose. Scutum pruinose bluish gray with a medial black band and a pair of lateral black bands (Fig. 5D ). Scutellum pale yellow with lateral corner dark brown. Subscutellum dark brown with anterior margin pale yellow. Mediotergite, anatergite, and katatergite brown. Pleuron largely yellow; postpronotal lobe with anterior brown spot; notopleuron with brown spot on venter; anepisternum and anepimeron with brown venters; katepisternum an meron with dark brown patches on venter (Fig. 5B ). Haltere gray, with grayish yellow stalk. Calypter margin and hairs gray. Leg segments brownish gray; tarsus darker. Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 5D ). Acrostichal setulae six or seven pairs in two rows. Wing: Wing length 1.7 mm, costa reaching M1 (Fig. 5A ). Length of ultimate section of vein M4 divided by penultimate section 1.9.

Abdomen: Abdomen dorsally subshiny brown; epandrium dark brown (Fig. 5E ). Genitalia: (Fig. 5G-J ) Epandrium rounded apically; inner-lateral margin with a large round arm having three or four unfused tubercle-like setae apically; inner-anterior surface with a large arm having a hand-shaped comb comprising four basally fused long tubercle-like setae apically, and one tubercle-like seta immediately inward from the protrusion (Fig. 5I ). Surstylus lobate, setose apically; inner-basally with a long, S-curved, hypertrophied, columnar arm, bearing one long tubercle-like seta apically (Fig. 5I ). Cercus narrow, setose, with a strong seta apically (Fig. 5I ). Subepandrial sclerite consisting of one pair of lateral plates (one seta each subapically on inner surface) forming (Fig. 5I ). Hypandrium slightly sclerotized along outer margin (Fig. 5G ). Postgonite bare, goose barnacle-shaped and cleft apically; upper lobe pointed apically (Fig. 5H ). Phallophorus with deep incision below (Fig. 5G ), articulated with phallapodeme, fused to epiphallus (Fig. 5H ). Basiphallus with a narrow plate on left side; dorsally lightly sclerotized; shorter than mesophallus. Hypophallus broad, membranous, ventral side covered with microtrichia, medially with a pair of short fused linear sclerites (Fig. 5G, H ). Paraphalli lobe-like, membranous; posterior margin slightly sclerotized (Fig. 5G, H ). Mesophallus dark, cylindrical, widest subbasally, slightly longer than distiphallus (Fig. 5H ). Distiphallus comprising one pair of stout tubules; basal half composed of ventral dark triangular sclerite and weaker medial region; distal half cylindrical, dorsally pigmented, with truncated, unpigmented apex (Fig. 5H ). Ejaculatory apodeme fan-shaped, blade pale with clear margin, with sclerotized stalk, broad asymmetric base, and clear sperm pump (Fig. 5J ).

Female (Fig. 5F-I ). Similar to male, but slightly larger and frons narrower (Fig. 5F ). Wing length 1.7 mm. Postabdomen: (Fig. 5K, L ) Oviscape dark brown, setigerous (Fig. 5K ). Tergite 10 cruciform, laterally uniting narrow pleural sclerites (Fig. 5L ). Each cercus with two stout, apical, trichoid sensilla, 1/3 length of cercus. Spermathecae orbicular (Fig. 5K ).

Etymology.

The specific name tsukuyomi is a Japanese word meaning brightness of moonlight, and refers to the bright yellow scutellum.

Japanese name.

Tsukuyomi-zenigoke-hamoguribae.

Host plant.

Marchantia polymorpha ( Marchantiaceae ).

Mine.

Larvae mine the thallus of the host plant and pupate in the mines. The mines are not apparent from the outside.

Biological notes.

The host plants from which this species emerged, grow on mesic soils on levee of paddy fields and along roads in natural beech forests (Fig. 5T ). Our rearing records suggest that this species is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Honshu (Fig. 2 ).

Remarks.

This species resembles P. alpicola in color pattern of the scutum (entirely dark mesothorax and uniformly pale scutellum); it is distinguished from the latter by the yellow pedicel and scape of the antenna (pedicel and scape of P. alpicola are brown), yellow maxillary palpus (dark gray in P. alpicola ), and number and arrangement of tubercle-like setae in a comb on the male epandrium (4 hand-shaped in P. tsukuyomi ; 6 fused in P. alpicola ).

Figures

Figure 2. Locality records of three Phytoliriomyza species associated with Marchantia spp.: P. dorsata, P. igniculus, P. tsukuyomi, P. marchantiae and P. nubatama.

Figure 5. Phytoliriomyza tsukuyomi sp. nov. A-E holotype male A habitus, B lateral C frontal D dorsal E posterior F paratype female (MK-AG-a 442) G-J male genitalia G whole genitalia, ventral H phallus complex, lateral I epandrium J ejaculatory apodeme, lateral K, L female postabdomen K oviscape and spermatheca L tergite 10 M mined thallus of Marchantia polymorpha.