20. Phytoliriomyza izayoi Kato sp. nov.

Figs 40, 41

Material examined.

Holotype: Japan: 1♂ (MK-AG-a402), Ashiu, Nantan, Kyoto Pref. (35.3261°N, 135.7239°E, 450 m asl), 8-V-2007 collected on thallus of Conocephalum orientalis, NSMT-I-Dip 32003. Paratypes: Japan: 1♀ (MK-AG-a262), Ashiu, Nantan, Kyoto Pref., 28-XI-1999 (as larva on C. orientalis), emerged on 17-IV-2000, NSMT-I-Dip 32004; 1♀ (MK-AG-520), Renge-onsen, Itoigawa, Niigata Pref., 14-VII-2009 (as larva on C. salebrosum), emerged on 5-V-2010, NSMT-I-Dip 32005; 1♂ (MK-AG-595), Mt. Hakusan, Hakusan, Ishikawa Pref., 3-V-2013 (as larva C. orientalis), emerged on 18-V-2013 NSMT-I-Dip 32006; 1♂1♀ (MK-AG-a249, 524), Nekata, Hamakita, Hamamatsu, Shizuoka Pref., 2-IV-2011 (as larva on C. orientalis), emerged on 18-20-IV-2011, NSMT-I-Dip 32007, 32007; 1♀ (MK-AG-574), Naiku, Oe, Fukuchiyama, Kyoto Pref., 17-III-2013 (as larva on C. orientalis), emerged on 5-IV-2013, NSMT-I-Dip 32009; 1♀ (MK-AG-624), Muramatsu, Iwakura, Sakyo-ku, Kyoto Pref., 5-IV-2019 (as larva on C. orientalis), emerged on 22-IV-2019, NSMT-I-Dip 32010; 1♀ (MK-AG-a392), Mt. Daimanji, Oki Is. Shimane Pref., 22-XI-2010 (as larva on C. orientalis), emerged on 7-IV-2011, NSMT-I-Dip 32011; 1♀ (MK-AG-587), Gakuen-ji, Bessho, Izumo, Shimane Pref., 11-I-2010 (as larva on C. orientalis), emerged on 14-IV-2011, NSMT-I-Dip 32012; 1♂ (MK-AG-a225), Koyadaira, Tokushima Pref., 22-IV-2019 (as larva on C. orientalis); emerged on 5-V-2019, NSMT-I-Dip 32013.

Other material.

Japan: On Conocephalum salebrosum: 1♂1♀, Renge-onsen, Itoigawa, Niigata Pref., 2-X-2011 (as larva), emerged on 29-IV-2012; 1♀, Sarukura, Hakuba, Nagano Pref., 9-VI-2013 (as larva), emerged on 28-VI-2013.

On Conocephalum orientalis: 5♀, Shokan-zawa, Mashike, Hokkaido, 4-X-2011 (as larva), emerged on 29-IV-6-V-2012; 1♂, Mt. Nanakura, Noshiro, Akita Pref., 14-X-2012 (as larva), emerged on 11-IV-2012; 1♂, Mt. Kiyosumi, Kamogawa, Chiba Pref., 24-I-2012 (as larva), emerged on 20-IV-2012; 5♂10♀, Nekata, Hamakita, Hamamatsu, Shizuoka Pref., 8-III-2012 (as larva), emerged on 27-III-26-IV-2012; 1♀, Takeda-gawa, Maruoka, Sakai, Fukui Pref., 18-III-2014 (as larva), emerged on 18-IV-2014; 3♂2♀, Akka, Iwaizumi, Iwate Pref., 20-II-2011 (as larva), emerged on 24-III-4-IV-2011; 2♂2♀, Suizu, Tsuruga, Fukui Pref., 11-III-2012 (as larva), emerged on 1-12-IV-2012; 3♂3♀, Seryo, Sakyo-ku, Kyoto Pref., 6-IV-2010 (as larva), emerged on 26-IV-12-V-2010; 2♂3♀, Naiku, Oe, Fukuchiyama, Kyoto Pref., 17-III-2013 (as larva), emerged on 4-18-IV-2013; 3♂6♀, Kibune, Sakyo-ku, Kyoto Pref., 6-IV-2010 (as larva), emerged on 20-IV-2010; 1♂2♀, Muramatsu, Iwakura, Sakyo-ku, Kyoto Pref., 28-IV-2015 (as larva), emerged on 10-18-IV-2015; 1♀, Mt. Kanpu, Ino, Agawa, Kochi Pref., 10-X-2016 (as larva), emerged on 30-II-2016.

On Conocephalum purpureorubrum: 1♀, Mt. Kiyosumi, Kamogawa, Chiba Pref., 14-IV-2010 (as larva), emerged on 2-V-2010; 1♀, Shirabiso-toge, Kamimura, Iida, Nagano Pref., 14-X-2011 (as larva), emerged on 28-IV-2011; 1♂, Kibune, Sakyo-ku, Kyoto Pref., 94-IV-2012 (as larva), emerged on 24-V-2012.

Diagnosis.

A large yellow species (wing length 2.4-2.5 mm) having a pruinose yellow scutum with a medial and a pair of dark brown lateral stripes, a yellow scutellum with dark lateral corners, black 1st flagellomere, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-distally with a long tubercle-like seta, and inner-basally with a comb consisting of 9-12 long fused tubercle-like setae. Larva mines the thallus of Conocephalum salebrosum and C. orientalis .

Description.

Adult male (Fig. 40A-D).

Head: Head entirely yellow including ocellar tubercle and back of head (Fig. 40C). Antenna porrect, first flagellomere black, pedicel and scape brown (Fig. 40B). Arista subbasal, pubescent. Face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus yellow, cylindrical (Fig. 40C). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 40B). Orbital setulae minute and erect, in a single row.

Thorax: Thorax subshiny. Scutum yellow with a black medial stripe on anterior 2/3, one pair of black suborbicular presutural patches confluent with the medial stripe, and a pair of wide black bands (i.e., fused complex of intra-alar and supra-alar stripes) on anterior 7/8, which is confluent with the presutural patches (Fig. 40D). Scutellum yellow with lateral margins brown (Fig. 40A, B). Subscutellum yellow. Mediotergite brown, but katatergite yellow, anatergite yellow with distal brown patch (Fig. 40B). Pleuron yellow with brown patches on propleuron centrally and on distal margins of notopleuron, anepisternum, katepisternum and meron (Fig. 40C). Haltere yellow. Calypter margin and hairs gray. Leg segments yellow; tibia and tarsus darker (Fig. 40A). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 40D). Acrostichal setulae in two rows. Wing: Wing length 2.4 mm, costa reaching M1 (Fig. 40A). Length of ultimate section of vein M4 divided by penultimate section 0.87.

Abdomen: Abdomen dorsally subshiny grayish yellow; epandrium dark brown (Fig. 40B). Genitalia: (Fig. 40G, K) Epandrium rounded apically; posterior end of inner margin with one tubercle-like seta; inner-anterior surface with a comb comprising 9-12 fused long tubercle-like setae (rarely unfused in part) and an irregular row of several (3-5) small tubercle-like setae immediately outward from the comb (Fig. 40J). Surstylus rounded, directed inwards, setose apically, with one (rarely 2 or 3) long tubercle-like seta on posterior margin (Fig. 40J). Cercus narrow, setose. Subepandrial sclerite V-shaped in a posterior view, dorsal lobe with one seta (Fig. 40J). Hypandrium slightly sclerotized along outer margin (Fig. 40G). Postgonite bare, goose barnacle-shaped, and cleft apically (Fig. 40H). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 40H, K). Basiphallus with dark broad lateral plate on left side and sclerotized anterodorsal margin (Fig. 40H). Hypophallus broad, membranous, and bilaterally asymmetrical; with a dark narrow sclerite on right side; medially with a pair of fused linear sclerites (Fig. 40K). Mesophallus dark, cylindrical, widest subbasally, 3/5 length of distiphallus, tapering distally (Fig. 40K). Distiphallus comprising one pair of stout tubules basally parallel to each other; basal half composed of ventral dark cuneiform sclerite and weaker medial region; distal half cylindrical, dorsally pigmented; with truncated, shortly flared unpigmented apex (Fig. 40H, K). Ejaculatory apodeme pale brown, fan-shaped with short broad stalk and clear sperm pump (Fig. 40I).

Female (Fig. 40E, F). Similar to male, but larger, frons wider. Wing length 2.3 mm. Postabdomen: (Fig. 41A, B) Oviscape dark brown, setigerous (Fig. 41A). Tergite 10 cruciform, laterally uniting narrow pleural sclerites (Fig. 41B). Each cercus with two stout, apical, trichoid sensilla, ¼ length of cercus (Fig. 41B). Spermathecae semi-orbicular, with truncate proximal ends (Fig. 41A).

Variation.

The number of tubercle-like setae in a comb in the male genitalia varied from 9 to 12. Although the number varied among individuals within a population and even between left and right sides of the epandrium in an individual, and the number was generally greater in western Honshu and Shikoku than in northern regions.

Etymology.

The specific name izayoi is a Japanese word meaning 16th moon, and refers to the non-circular yellow pattern of scutum.

Japanese name.

Izayoi-jagoke-hamoguribae.

Host plants.

Conocephalum salebrosum, C. orientalis and C. purpureorubrum ( Conocephalaceae).

Mine.

(Fig. 41G-I) Larvae construct linear mines in the thallus in early instars, later entering the midrib, and pupate in the mines.

Biological notes.

The habitats of this species are stream banks and mesic slopes in temperate deciduous forests dominated by Fagus crenata, Quercus crispula and Cryptomeria japonica (Fig. 41D-F). It is sympatric with P. luteola and P. conocephali in some localities. Our rearing records suggest that this species is univoltine, and that adults emerge from overwintered pupae in spring. The female’s oviposition behavior on C. orientalis thalli was observed on 1 July 2021 in a beech forest at Renge-Onsen.

Distribution.

Japan: Hokkaido, Honshu, Shikoku (Fig. 39).

Remarks.

This species resembles P. islandica and P. bornholmensis; it is distinguished from them based on the following characters: lateral black bands terminate before reaching scutellum (lateral black bands confluent with scutellum in the latter two); male epandrium with a comb of 9-12 tubercle-like setae (6 in P. islandica, 8 in P. bornholmensis); male epandrium with one tubercle-like seta on middle inner surface (1-2 on middle inner margin in P. islandica; three on inner margin in P. bornholmensis); basal half of distiphallus curved outward and with weaker medial region (basal half of distiphallus curved outward and without weaker medial region in P. islandica; angular and with weaker medial region in P. bornholmensis). This species also resembles P. admirabilis recorded from Nepal; it is distinguished from the latter based on the following characters: halteres yellow (black in the latter); male genitalia lack paraphallus (paraphallus present in the latter); surstylus with one tubercle-like seta (without tubercle-like seta in the latter); ejaculatory apodeme with a short broad stalk (with a slender stalk in the latter).

Among the Japanese species, P. izayoi resembles P. luna, P. chichibuensis, and P. caliginosa in size and in having a pair of dark broad lateral bands on the scutum; it is distinguished from P. luna by the dark-sided scutellum (scutellum only yellow in P. luna), from P. chichibuensis and P. caliginosa by the dark lateral bands not confluent with medial stripe (lateral bands confluent with medial stripe in the other species) and by the tubercle-like setae borne on the distal margin of the male epandrium (tubercle-like setae borne on inner surface of epandrium in the others).