31. Phytoliriomyza lanternaria Kato sp. nov.

Fig. 58

Material examined.

Holotype: Japan: 1♂ (MK-AG-a290), Hachijo Is., Tokyo Pref. (33.1114°N, 139.8271°E, 190 m asl), 17-II-2012 (as larva on C. orientalis), emerged on 23-IV-2013, NSMT-I-Dip 32071. Paratypes: Japan: 1♂2♀ (MK-AG-a5, a430, 730), same data as holotype, emerged on 8-IV-2-V-2013, NSMT-I-Dip 32072-32074; 1♀ (MK-AG-a473), Anbo, Yaku Is., Kumage, Kagoshima Pref., 30-III-2017 (as larva on C. orientalis), emerged on 15-VII-2017, NSMT-I-Dip 32075.

Other material.

Japan: On Conocephalum orientalis: 2♂, Mt. Horoiwa, Saroma, Tokoro, Hokkaido, 1-V-2021 (as larva), emerged on 7-VI-2021; 1♀, Namari-kawa, Yakumo, Futami, Hokkaido, 2-VI-2021 (as larva), emerged on 16-VI-2016; 3♂9♀, Hachijo Is., Tokyo Pref., 17-II-2012 (as larva), emerged on 8-IV-2-V-2012; 1♀, Fuchigasawa, Kimitsu, Chiba Pref., 13-V-2008 (as larva), emerged on 31-V-2013.

Diagnosis.

A medium-sized dark species (wing length 1.8-1.9 mm) having pruinose dark gray scutum with mid-posterior yellow margin, yellow scutellum with dark lateral corners, black 1st flagellomere, dark maxillary palpus, dark halteres, and yellowish brown legs. Male epandrium inner-laterally with a long ventrally directed tubercle-like seta, and inner-basally with a siku-shaped comb comprising seven fused tubercle-like setae.

Larva mines the thallus of Conocephalum orientalis .

Description.

Adult male (Fig. 58A-D).

Head: Head light yellow, with ocellar tubercle dark brown, frons yellowish brown, back of head dark brown excluding margins (Fig. 58C). Antenna porrect, first flagellomere black, pedicel and scape brown (Fig. 58B). Arista subbasal, black, pubescent. Clypeus, face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus brown, cylindrical (Fig. 58C). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 58B). Orbital setulae minute and erect, in a single row.

Thorax: Thorax pruinose. Scutum pruinose gray, with a small yellow patch along midposterior margin (Fig. 58D). Scutellum light yellow with lateral corner brown, subscutellum light yellow. Mediotergite and anatergite brown, katatergite light yellow (Fig. 58B). Pleuron yellow with brownish patches on venter of propleuron, anepisternum, katepisternum, anepimeron, and meron (Fig. 58C). Haltere yellow but light yellow basally. Calypter margin and hairs gray. Leg segments brownish, basal half of femur paler (Fig. 58A). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 58B). Acrostichal setulae five or six pairs in two rows. Wing: Wing length 2.2 mm, costa reaching M1 (Fig. 58A). Length of ultimate section of vein M4 divided by penultimate section 1.3.

Abdomen: Abdomen dorsally subshiny brown; epandrium dark brown (Fig. 58B). Genitalia: (Fig. 58F-I) Epandrium rounded apically; inner-lateral surface with a long, anteriorly directed, tubercle-like seta; inner-anterior surface with a siku-shaped comb comprising seven fused tubercle-like setae, which are reduced in length toward base of surstylus (Fig. 58H, I). Surstylus rounded, curved inwards, setose subapically, with one long tubercle-like seta apically (Fig. 58H). Cercus narrow, setose. Subepandrial sclerite with a pair of plate-like arms, each having a posterior lobe with trilobed projection and ventrally projected lateral plates (Fig. 58H). Hypandrium slightly sclerotized along outer margin (Fig. 58F). Postgonite bare, goose barnacle-shaped, pointed apically (Fig. 58F). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 58F, G). Basiphallus with pale broad plate-like sclerite on left side (Fig. 58F). Hypophallus broad, membranous covered with microtrichia ventrally; lateral margins lightly sclerotized; medially with a pair of fused, narrow, ventrally incurved sclerites (Fig. 58F, G). Paraphallus pale, membranous, and wing-like; posterior margins lightly sclerotized; paraphalli diverging, angled anteroventrally, jointed basally (Fig. 58F, G). Mesophallus dark, cylindrical, widest subbasally, as long as distiphallus (Fig. 58G). Distiphallus comprising one pair of stout tubules basally parallel to each other; basal half composed of ventral dark subtriangular sclerite and weaker medial region; distal half cylindrical, dorsally pigmented, widening toward truncated, flared apex (Fig. 58G). Ejaculatory apodeme pale brown, fan-shaped with short broad stalk and clear sperm pump (Fig. 58F).

Female (Fig. 58E, O). Similar to male, but slightly larger and frons wider. Wing length 2.3 mm. Postabdomen: (Fig. 58J, K) Oviscape dark brown, setigerous (Fig. 58J). Tergite 10 cruciform, laterally uniting narrow pleural sclerites (Fig. 58K). Each cercus with two stout, apical, trichoid sensilla, 1/3 length of cercus (Fig. 58K). Spermathecae orbicular (Fig. 58J).

Variation.

Color pattern of scutum and subscutellum varied among localities. In specimens from Hachijo Island, the subscutellum had a large lateral dark corner.

Etymology.

The specific name (lanterna = lantern) refers to the faint yellow spot on the scutellum, which reminds us of a lantern light.

Japanese name.

Tomoshibi-jagoke-hamoguribae.

Host plants.

Conocephalum orientalis ( Conocephalaceae) growing on mesic soils in various types of forests.

Mine.

Larvae construct linear mines in the thallus in early instars, later entering the midrib, and pupate in the mines (Fig. 58M, N).

Biological notes.

The habitats of this species are stream banks and mesic slopes in warm temperate evergreen forests dominated by Castanopsis cuspidata and cool temperate deciduous forests dominated by Quercus crispula (Fig. 58L). It is sympatric with P. luteola and P. conocephali at some localities. Our rearing records suggest that this species is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Hokkaido, Honshu, Hachijo Island, and Yaku Island (Fig. 55).

Remarks.

This species resembles P. marchantiae, P. rebouliae, and P. conocephali in having a small yellow mark lying between the posterior scutum and subscutellum, but is distinguished from them by its larger size (wing length ≥ 1.9 mm in P. lanternaria;&nbsp;<&nbsp;1.8&nbsp;mm in the other species). It is also distinguished from P. marchantiae and P. rebouliae by the absence of a tubercle-like seta on the surstylus of the male epandrium, and from P. conocephali by the number of tubercle-like setae in a comb of the male epandrium (7 in P. lanternaria; 5-6 in P. conocephali). This species resembles P. alpicola in the color patterns of the scutum, but is distinguished from the latter by its gray scutum (scutum darker in P. alpicola), dark-sided scutellum (scutum dark only on a marginal narrow lateral area in P. alpicola), and number and arrangement of tubercle-like setae on the male epandrium (a siku-shaped comb composed of seven differently sized setae in P. lanternaria; a comb composed of six equally long setae in P. alpicola).