Phytoliriomyza calcicola 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

10. Phytoliriomyza calcicola Kato sp. nov.

Figs 18 , 19

Material examined.

Holotype: Japan: 1♂ (MK-AG-a265), Todai-shiraiwa, Ina, Nagano Pref. (35.7723°N, 138.1620°E, 1140 m asl), 30-IV-2011 (as larva), emerged on 24-V-2011, NSMT-I-Dip 31943. Paratypes: Japan: 1♀ (MK-AG-a459), same data as holotype emerged on 2-VI-2011, NSMT-I-Dip 31944; 1♀ (MK-AG-a222), Ozasu, Ogano, Chichibu, Saitama Pref., 10-IX-2017 (as larva), emerged on 13-X-2017, NSMT-I-Dip 31945.

Other material.

Japan: 1♀, Narahara, Ueno, Tano, Gunnma Pref., 18-IV-2021 (as larva), emerged on 1-VI-2021; 1♀1♂, Ozasu, Ogano, Chichibu, Saitama Pref., 10-IX-2017 (as larva), emerged on 9-13-X-2017; 1♀, Irisawai, Oshika, Nagano Pref., 29-IV-2011 (as larva), emerged on 22-V-2011.

Diagnosis.

A medium-sized yellow species (wing length 1.6-1.7 mm) having subshiny yellow scutum with two pairs of lateral stripes, yellow 1st flagellomere, yellow maxillary palpus, yellow halteres, and yellow legs. Male epandrium inner-subdistally with a hypertrophied arm which bears an enlarged tubercle-like seta; inner-basally with a hypertrophied arm which bears a comb comprising five or six fused tubercle-like setae. Larva mines the thallus of Plagiochasma pterospermum .

Description.

Adult male (Fig. 18A-D ).

Head: Head light yellow, with ocellar tubercle brown, back of head dark brown (Fig. 18C ). Antenna porrect, first flagellomere, pedicel and scape yellow (Fig. 18B ). Arista subbasal, black pubescent. Clypeus, face, gena, parafacial and postgena yellow. Proboscis normal, yellow; palpus yellow, cylindrical (Fig. 18C ). Chaetotaxy: Front orbitals three pairs; one ori directed inward; two ors directed upward (Fig. 18B ). Orbital setulae minute and erect, in a single row.

Thorax: Thorax subshiny. Scutum yellow with medial black stripe on anterior 2/3, with a pair of narrow black supra-alar stripes and a pair of wider. Black intra-alar stripes, which adjoin a pair of lateral presutural black ovoid spots (Fig. 18D ). Mediotergite brown, and anatergite and katatergite yellow. Pleuron largely yellow, anepisternum and anepimeron with small brown patches, venters of katepisternum and meron brown (Fig. 18B ). Haltere yellow, with upper surface grayish. Calypter margin and hairs gray. Leg segments yellow; tibia and tarsus darker (Fig. 18A ). Chaetotaxy: Scutum with 1+3 dorsocentrals, shortened anteriorly (Fig. 18D ). Acrostichal setulae seven pairs in two rows. Wing: Wing length 1.7 mm, costa reaching M1 (Fig. 18A ). Length of ultimate section of vein M4 divided by penultimate section 0.95.

Abdomen: Abdomen dorsally subshiny yellow (Fig. 18B ). Genitalia: (Fig. 18I, J ) Epandrium dark brown, rounded apically; inner-distal margin with a basally enlarged, slightly flattened hypertrophied arm, which bears a dark laterally enlarged tubercle-like seta; inner-anterior surface also with a basally enlarged, slightly flattened, hypertrophied arm, on which with a comb comprising five or six fused tubercle-like setae (Fig. 18G ). Surstylus plate-like, extruded ventrally, bare, with one long tubercle-like seta apically (Fig. 18G ). Cercus narrow, setose. Subepandrial sclerite V-shaped in posterior view, with a pair of setae medially (Fig. 18G ). Hypandrium slightly sclerotized along outer margin. Postgonite bare and goose barnacle-shaped with incurved pointed apex (Fig. 18H ). Phallophorus with deep incision below, articulated with phallapodeme, fused to epiphallus (Fig. 18H ). Basiphallus shorter than mesophallus. Hypophallus broad, membranous, with a dark narrow sclerite medially, and with a pair of diverging, ventrally incurved narrow sclerites (Fig. 18H ). Paraphallus absent. Mesophallus dorsoventrally flattened tubular, parallel-sided; twofold longer than distiphallus; basal half and distal 1/5 pigmented (Fig. 18H ). Distiphallus comprising one pair of tubules; basal half unpigmented; distal half cylindrical, pigmented, with truncated, unpigmented apex (Fig. 18H ).

Female (Fig. 18E-F ). Similar to male, but slightly larger and frons wider. Wing length 1.6 mm. Postabdomen: (Fig. 19A, B ) Oviscape dark brown, setigerous (Fig. 19A ). Tergite 10 trifurcate, laterally uniting narrow pleural sclerites. (Fig. 19B ) Each cercus with two stout, apical, trichoid sensilla, ¾ length of cercus (Fig. 19B ). Spermathecae orbicular.

Etymology.

The specific name (calcis = limestone) refers to the fact that this species is associated with the host liverwort growing only on limestone.

Japanese name.

Kurosuji-tsubozenigoke-hamoguribae.

Host plant.

Plagiochasma pterospermum ( Aytoniaceae ).

Mine.

Larvae construct radiate mines in the thallus and pupate in the mines (Fig. 19D ).

Biological notes.

The habitats of this species are limestone outcrops in temperate deciduous forests, where the host liverworts grow (Fig. 19C ). This species is one of the rarest species in liverwort-associated species, and was sympatric with P. arcus or P. plagiochasmatos in some localities. Our rearing records suggest that this species is univoltine, and that adults emerge from overwintered pupae in spring.

Distribution.

Japan: Honshu (Fig. 16 ). Recorded only from limestone areas in Chichibu Mountains and Akaishi Mountain Range.

Remarks.

This species has several unique characteristics in male genitalia: a flattened stout tubercle-like seta on distal margin of epandrium; a comb of tubercle-like setae borne on enlarged projection of inner surface of epandrium; thin, bare surstylus; short distiphallus unpigmented at basal half. The unique characteristics suggest distant relation of this species from other liverwort-associated species. This species resembles P. nigroflava and P. brunofasciata in having two pairs of dark stripes on dorsal scutum; it is distinguished from them by the dark haltere (haltere yellow in P. nigroflava and P. brunofasciata ).

Species associated with Asterella

Figures

Figure 16. Locality records of three Phytoliriomyza species associated with Plagiochasma spp.: P. arcus, P. plagiochasmatos and P. calcicola.

Figure 18. Phytoliriomyza calcicola sp. nov. A-D holotype male A habitus B lateral C frontal D dorsal E, F paratype female (MK-AG-a 222) E dorsal F posterior G, H male genitalia G epandrium H phallic complex in lateral view I live female fly.

Figure 19. Female morphology and larval / adult ecology of Phytoliriomyza calcicola sp. nov. A, B female postabdomen A oviscape and spermatheca B tergite 10 C habitat at type locality D mined thallus of Plagiochasma pterospermum.