Phytoliriomyza megacerotis 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

38. Phytoliriomyza megacerotis Kato sp. nov.

Figs 72 , 73

Material examined.

Holotype: Japan: 1♂ (MK-AG-a417), Kotonotaki, Susami, Wakayama Pref. (33.5639°N, 135.5437°E, 200 m asl), 24-III-2020 (as larva), emerged on 1-V-2020, NSMT-I-Dip 32114. Paratypes: Japan: 1♂2♀ (MK-AG-a479, a480, a14), same data as holotype, emerged on 30-IV-2-V-2020, NSMT-I-Dip 32115-32117; 1♀ (MK-AG-146), Tashiro, Kinko, Kimotsuki, Kagoshima Pref., 22-III-2015 (as larva), emerged on 1-V-2015, NSMT-I-Dip 32118; 1♂1♀ (MK-AG-154, a15), Yasukawa-keikoku, Tanabe, Wakayama Pref., 31-VII-2015 (as larva), emerged on 3-IX-2015, NSMT-I-Dip 32119-32120.

Other material.

Japan: 8♂9♀, Kotonotaki, Susami, Wakayama Pref., 24-III-2020 (as larva), emerged on 31-I-2-V-2020; 16♂28♀, Yasukawa-keikoku, Tanabe, Wakayama Pref., 31-VII-2015 (as larva), emerged on 25-VIII-2-IX-2020; 1♀, Wadagawa-kyo, Kumanogawa, Shingu, Wakayama Pref., 7-VII-2021 (as larva), emerged on 18-VIII-2021; 9♂25♀, Tashiro, Kinko, Kimotsuki, Kagoshima Pref., 22-III-2015 (as larva), emerged on 30-IV-30-IV-10-V-2020; 1♀, Isso, Yaku Is., Kumage, Kagoshima Pref., 29-III-2017 (as larva), emerged on 12-V-2021.

Diagnosis.

A small species (wing length 1.2-1.4 mm) having a pruinose gray scutum and scutellum, black 1st flagellomere, black maxillary palpus, dark gray halteres, and dark gray legs. Male epandrium inner-basally with a comb comprising five or six fused long tubercle-like setae; surstylus with a comb comprising five or six fused long tubercle-like setae. Larva mines the thallus of a riparian hornwort, Megaceros flagellaris .

Description.

Adult male (Fig. 72A-E ).

Head: Head dark yellow, with ocellar tubercle dark brown, and back of head dark brown excluding margins (Fig. 72C ). Antenna porrect; first flagellomere black, pedicel and scape brown (Fig. 72B ). Arista subbasal, brown, pubescent. Frons brownish yellow, with reflective pruinosity. Clypeus narrow, brown with apical half yellow; slightly protruding. Face, gena, parafacial and postgena dark yellow (Fig. 72C ). Proboscis normal, light yellow; palpus dark brown, cylindrical. Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 72B ). Orbital setulae minute and proclinate, in a single row.

Thorax: Thorax pruinose, dark gray. Scutum pruinose, dark brown; scutellum pruinose, brown; subscutellum light yellow (Fig. 72D ). Mediotergite subshiny, dark brown, anatergite and katatergite brown (Fig. 72E ). Pleuron largely dark yellow; postpronotal lobe with anterior brown patch; propleuron with a small brown patch on anterior corner; notopleuron yellowish brown; anepisternum dark yellow with lower-half yellowish brown; anepimeron with anterior brown patch; katepisternum and meron with large brown patches on venter (Fig. 72B ). Haltere brown. Calypter margin and hairs gray. Leg segments dark brown; tibia and tarsus darker (Fig. 72A ); distal half of coxa and basal half of femur of foreleg pale yellow frontally (Fig. 72C ). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 72D ). Acrostichal setae two or three pairs in two rows. Wing: Wing length 1.2 mm, costa reaching M1 (Fig. 72A ). Length of ultimate section of vein M4 divided by penultimate section 1.6-1.8.

Abdomen: Abdomen dorsally subshiny brown; epandrium brown (Fig. 72E ). Genitalia: (Fig. 72G-J ) Epandrium rounded apically; distal margin with several long setae; inner-basal margin with a comb comprising five or six fused dark long tubercle-like setae (Fig. 72H ). Surstylus rounded, apically with a comb comprising five or six fused dark long tubercle-like setae (Fig. 72H ). Cercus narrow, setose. Subepandrial sclerite dark, with a pair of pale, elongated, fused, plate-like dorsal lobes (Fig. 72H ). Hypandrium thin, sclerotized along outer margin (Fig. 72G ). Postgonite bare, goose barnacle-shaped, cleft apically (Fig. 72G ). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 72J ). Basiphallus membranous, with dorsal surface sclerotized. Hypophallus small, with a pair of asymmetrical narrow sclerites; the left one is longer than the right one (Fig. 72G, J ). Paraphallus absent. Mesophallus cylindrical, with a pair of dorsolateral sclerites (Fig. 72J ). Distiphallus comprising one pair of tubules; the tubules adjoining only at the base, tapering toward tip, with outer-lateral sides pigmented, extending up to half point of phallapodeme, becoming paler apically (Fig. 72J ). Ejaculatory apodeme brownish, spatula-shaped with short, broad stalk; base dark and wide to one side; sperm pump clear (Fig. 72I ).

Female (Fig. 72F ). Similar to male, but larger, frons wider. Wing length 1.4 mm. Postabdomen: (Fig. 72K, L ) Oviscape dark brown, setigerous (Fig. 72K ). Tergite 10 cruciform, laterally uniting narrow pleural sclerites (Fig. 72L ). Each cercus with two stout, apical, trichoid sensilla, 1/2 length of cercus (Fig. 72L ). Spermathecae semi-orbicular, with truncate proximal ends (Fig. 72K ).

Immatures. (Fig. 73D ) Puparium internal, slender, brown, and slightly flattened, with posterior 1/3 tapering.

Etymology.

The specific name refers to the host plant genus Megaceros .

Japanese name.

Ananashitsunogoke-hamoguribae.

Host plant.

Megaceros flagellaris ( Dendrocerotaceae ).

Mine.

Larvae construct linear-blotch mines in the thallus, and pupate in and rarely out of the mines (Fig. 73C-E ).

Biological notes.

The habitats of this species are watersides along river banks or near water fall in warm temperate evergreen forests dominated by Castanopsis sieboldii (Fig. 73B ), and is unique in that the host hornworts are always wet due to splashed water (Fig. 73A ). Our rearing records suggest that this species is at least bivoltine, with adults emerging in May and August.

Distribution.

Japan: Honshu, Kyushu and Yaku Island (Fig. 71 ).

Remarks.

This species resembles P. suetsugui and P. ricciae in having a wholly dark scutum and dark maxillary palpus, but is distinguished from them by the color of the pedicel and scape of the antenna (dark in P. megacerotis ; yellow in P. suetsugui and P. ricciae ).

Figures

Figure 71. Locality records of three Phytoliriomyza species associated with hornworts: P. foliocerotis, P. megacerotis and P. phaeocerotis.

Figure 72. Phytoliriomyza megacerotis sp. nov. A-E holotype male A habitus B lateral C frontal D dorsal E posterior F paratype female (MK-AG-a 14), dorsal G-J male genitalia (G at type locality H, I at Tashiro J at Yasukawa-keikoku) G whole genitalia, ventral H epandrium, ventral I ejaculatory apodeme, lateral J phallic complex, lateral K, L female postabdomen K oviscape and spermatheca L tergite 10.

Figure 73. Larval ecology of Phytoliriomyza megacerotis sp. nov. A, B habitats (A at type locality B at Yakushima) C-E mined thalli of Megaceros flagellaris C, D at type locality E at Tashiro. An arrow indicates internal puparium.