16. Phytoliriomyza aratriformis Kato sp. nov.

Fig. 32

Material examined.

Holotype: Japan: 1♂ (MK-AG-a311), Tazukawa-keikoku, Katsuura, Tokushima Pref. (33.8952°N, 134.4608°E, 270 m asl), 30-III-2021 (as larva), emerged on 23-IV-2021, NSMT-I-Dip 31981. Paratypes: Japan: 1♂ (MK-AG-a463), type locality, 11-X-2016 (as larva), emerged on?-IV-2017, NSMT-I-Dip 31982; 1♀ (MK-AG-427), Nakatsugawa-keikoku, Chichibu, Kyoto Pref., 14-XI-2010 (as larva), emerged on 4-V-2011, NSMT-I-Dip 31983; 1♀ (MK-AG-a17), Kanna-gawa, Nakatsugawa, Chichibu, Saitama Pref., 14-XI-2010 (as larva), emerged on 14-IV-2021, NSMT-I-Dip 31984; 1♂ (MK-AG-a346), Naiku, Oe, Fukuchiyama, Kyoto Pref., 19-V-2010 (as larva), emerged on 20-VI-2021, NSMT-I-Dip 31985.

Other material.

Japan: 1♂, Ryugakyo, Yamashiro, Miyoshi, Tokushima Pref., 21-IV-2014 (as larva), emerged on 2-V-2014.

Diagnosis.

A medium-sized yellow species (wing length 1.9-2.3 mm) having a subshiny brown scutum with an obscure oval yellow pattern extending from the mid-posterior margin to the scutellum, a yellow 1st flagellomere, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-laterally with a long hypertrophied, ventrally curved arm that apically bears a dark, apically bifid tubercle-like seta. Larva mines the thallus of Reboulia hemisphaerica orientalis .

Description.

Adult male (Fig. 32A-D).

Head: Head light yellow, with ocellar tubercle dark brown, frons yellowish brown, back of head dark brown excluding margins (Fig. 32C). Antenna porrect, first flagellomere black, pedicel and scape brown (Fig. 32B). Arista subbasal, black, pubescent. Clypeus, face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus brown, cylindrical (Fig. 32C). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 32B). Orbital setulae minute and erect, in a single row.

Thorax: Thorax pruinose. Scutum pruinose gray, with a small yellow patch along midposterior margin (Fig. 32D). Scutellum light yellow with lateral corner brown, subscutellum light yellow. Mediotergite and anatergite brown, katatergite light yellow. Pleuron yellow with brownish patches on venter of propleuron, anepisternum, katepisternum, anepimeron, and meron (Fig. 32B). Haltere yellow but light yellow basally. Calypter margin and hairs gray. Leg segments brownish, basal half of femur paler (Fig. 32A). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 32D). Acrostichal setulae seven or eight pairs in two rows. Wing: Wing length 2.2 mm, costa reaching M1 (Fig. 32A). Length of ultimate section of vein M4 divided by penultimate section 1.3.

Abdomen: Abdomen dorsally subshiny brown; epandrium dark brown (Fig. 32A). Genitalia: (Fig. 32K-O) Epandrium rounded apically; inner-anterior margin with two short tubercle-like setae; inner-lateral surface with a basally enlarged, extremely extended/thickened, ventrally curved arm, bearing a dark bifid tubercle-like seta borne (Fig. 32H). Surstylus narrow, extended, curved inwards, setose apically (Fig. 32H). Cercus narrow, setose. Subepandrial sclerite consisting of one pair of flat plate-like, basally fused, dorsal sclerites, and one pair of pale plate-like, separated, ventral lobes (Fig. 32H). Hypandrium slightly sclerotized along outer margin (Fig. 32F). Postgonite bare, goose barnacle-shaped, and cleft apically; dorsal lobe pointed apically (Fig. 32J). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 32H). Basiphallus with a pair of broad lateral lobes (Fig. 32F). Hypophallus broad, membranous, and bilaterally asymmetrical; right lateral margin well sclerotized, left lateral margin basally sclerotized; medially with a pair of fused linear sclerites (Fig. 32F, I). Paraphallus 4-winged, with posterior margin lightly sclerotized; paraphalli diverging, angled anteroventrally, jointed basally (Fig. 32H, I). Mesophallus dark, cylindrical, widest subbasally, as long as distiphallus (Fig. 32H). Distiphallus comprising one pair of stout tubules; basal half with pigmented and weaker medial regions; distal half cylindrical, dorsally pigmented, widening toward truncated shortly flared unpigmented apex (Fig. 32I).

Female (Fig. 32E, M). Similar to male, but slightly larger, and dorsal abdomen paler (Fig. 32E). Wing length 2.3 mm. Postabdomen: (Fig. 32K, L) Oviscape dark brown, setigerous (Fig. 32K). Tergite 10 trifurcate, laterally uniting narrow pleural sclerites (Fig. 32L). Each cercus with two stout, apical, trichoid sensilla, 1/3 length of cercus (Fig. 32L). Spermathecae orbicular (Fig. 32K).

Etymology.

The specific name (aratriformis = plow-shaped) refers to the plow-shaped tubercle-like seta on the male epandrium.

Japanese name.

Karasuki-jingasagoke-hamoguribae.

Host plant.

Reboulia hemisphaerica orientalis ( Aytoniaceae).

Mine.

Larva constructs linear mine in the thallus, and pupate in the mine (Fig. 32O).

Biological notes.

The habitats of this species are rocky cliffs in warm temperate evergreen forests (Fig. 32N). This species is rare, sympatric with P. argentifasciata and P. falcata in some localities. Our rearing records suggest that it is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Honshu, Shikoku, Tsushima Island (Fig. 31).

Remarks.

This species resembles P. arcus, P. plagiochasmatos and P. falcata in having a pair of brown lateral bands and a pale yellow mark on the scutum, but is distinguished from all of these species by the small, ill-defined yellow mark on the scutum (the mark larger and well-defined in the other species), and by the presence of a stout, curved, plow-shaped tubercle-like seta on the subdistal margin of the male epandrium.