Phytoliriomyza helva 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

28. Phytoliriomyza helva Kato sp. nov.

Figs 52 , 53

Material examined.

Holotype: Japan: 1♂ (MK-AG-a540), Mitsumine, Chichibu, Saitama Pref. (35.9299°N, 138.9171°E, 630 m asl), 26-III-2021 (as larva on C. purpureorubrum ), emerged on 17-V-2021, NSMT-I-Dip 32057. Paratypes: Japan: 1♀ (MK-AG-a541), same data as holotype, NSMT-I-Dip 32058. 2♂2♀ (MK-AG-a406, a471, a318, a470), Eniwa-keikoku, Eniwa, Hokkaido, 2-V-2021 (as larva on C. salebrosum ), emerged on 10-15-VI-2021, NSMT-I-Dip 32059-32062.

Other material.

Japan: On Conocephalum salebrosum : 1♂, Mt. Horoiwa, Saroma, Tokoro, Hokkaido, 1-X-2016 (as larva), emerged on 4-V-2016; 1♂, Usuzuka, Fujinomiya, Funbe, Hiroo, Hokkaido Pref., 27-VIII-2014 (as larva), emerged on 16-V-2014.

On Conocephalum purpureorubrum : 1♂1♀, Iwaobetsu, Shari, Hokkaido, 1-V-2021 (as larva), emerged on 11-15-VI-2021; 1♀, Samani-dam, Samani, Hokkaido, 30-IV-2021 (as larva), emerged on 15-VI-2021.

Diagnosis.

A medium-sized yellow species (wing length 1.8-2.1 mm) having a pruinose light yellow scutum and scutellum, a yellow 1st flagellomere, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-laterally with an extended, apically flattened tubercle-like seta, and inner-basally with a comb comprising three or four long fused tubercle-like setae. Larva mines the thallus of Conocephalum salebrosum and C. purpureorubrum .

Description.

Adult male (Fig. 52A-E ).

Head: Head yellow, with back of head dark brown excluding margins (Fig. 52C ). Antenna porrect, first flagellomere, pedicel and scape yellow (Fig. 52B ). Arista subbasal, black but basally yellow, pubescent. Clypeus, face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus yellow, cylindrical (Fig. 52C ). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 52D ). Orbital setulae minute and erect, in a single row.

Thorax: Thorax pruinose. Scutum entirely light yellow (Fig. 52D ). Scutellum, subscutellum, mediotergite, anatergite, and katatergite yellow (Fig. 52E ). Pleuron entirely yellow (Fig. 52B ). Haltere yellow. Calypter margin and hairs gray. Leg segments entirely yellow; tibia and tarsus darker. Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 52D ). Acrostichal setulae five or six pairs in two irregular rows. Wing: Wing length 2.0 mm, costa reaching M1 (Fig. 52A ). Length of ultimate section of vein M4 divided by penultimate section 1.1-1.3.

Abdomen: Abdomen dorsally subshiny yellow; epandrium brown (Fig. 52E ). Genitalia: (Fig. 52G-J ) Epandrium rounded apically;inner-lateral surface with an elongated tubercle-like seta, whose tip is slightly spread and flattened; inner-basal surface with a comb comprising 3-5 fused long tubercle-like setae (rarely unfused in part) and a row of two short tubercle-like setae immediately outward from the comb (Fig. 52I ). Surstylus rounded, directed inwards, setose apically, with one long tubercle-like seta on posterior margin (Fig. 52I ). Cercus narrow, setose. Subepandrial sclerite V-shaped, with bilobed dorsal plate and a pair of pale plate-like arms (Fig. 52I ). Hypandrium slightly sclerotized along outer margin (Fig. 52G ). Postgonite bare, goose barnacle-shaped, rounded apically (Fig. 52G ). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 52G, H ). Basiphallus with broad plate on left side and lightly sclerotized anterodorsal margin (Fig. 52G, H ). Hypophallus hood-shaped, membranous covered with microtrichia ventrally; lateral margins lightly sclerotized; medially with a pair of fused narrow sclerites (Fig. 52H ). Paraphallus pale membranous, undefined (Fig. 52H ). Mesophallus dark, cylindrical, as long as distiphallus. Distiphallus comprising one pair of stout tubules; basal half composed of dark sclerite and weaker medial region; distal half cylindrical, pigmented; widening toward inflated, truncated apex (Fig. 52H ). Ejaculatory apodeme pale, with fan-shaped blade and broad stalk; base wide to one side; sperm pump clear (Fig. 52J ).

Female (Figs 52F , 53E ). Similar to male, but slightly larger and frons wider. Wing length 2.1 mm. Postabdomen: (Fig. 53A, B ) Oviscape dark brown, setigerous (Fig. 53A ). Tergite 10 trifurcate, laterally uniting narrow pleural sclerites (Fig. 53B ). Each cercus with two stout, apical, trichoid sensilla, 1/3 length of cercus (Fig. 53B ). Spermathecae orbicular (Fig. 53A ).

Variation.

The number of tubercle-like setae in a comb of the male epandrium varied from 3 to 5 among localities, with the individuals from northern localities having fewer tubercle-like setae. Pigmentation pattern in distiphallus and morphology of paraphallus also differed between Hokkaido and Honshu populations.

Etymology.

The specific name (helvus = pale yellow) refers to pale yellow body and antennae of this species.

Japanese name.

Usuki-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. 53D ).

Biological notes.

The habitats of this species are stream banks and mesic slopes in cool temperate deciduous forests dominated by Quercus crispula and Ulmus davidiana (Fig. 53C ). This species is sympatric with P. luteola at some localities. Our rearing records suggest that it is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Hokkaido, Honshu (Fig. 50 ). Co-occurs with P. luteola .

Remarks.

This species resembles P. pallidofasciata and P. luteola in having wholly yellow body; it is distinguished from them by the color of the 1st flagellomere (yellow in P. helva ; black in the latter).

Figures

Figure 50. Locality records of three Phytoliriomyza species associated with Conocephalum spp.: P. pallidofasciata, P. luteola and P. helva.

Figure 52. Phytoliriomyza helva sp. nov. A-E holotype male A habitus B dorsal C frontal D dorsal E posterior F paratype female (MK-AG-a 541), frontal G-J male genitalia G whole genitalia, ventral H phallic complex, lateral I epandrium, ventral J ejaculatory apodeme, lateral.

Figure 53. Female morphology and larval / adult ecology of Phytoliriomyza helva sp. nov. A, B female postabdomen A oviscape and spermatheca B tergite 10 C habitat at Eniwa D mined thallus of Conocephalum salebrosum E live fly at Eniwa.