Phytoliriomyza pulchella Spencer, 1986

Lonsdale, Owen, 2021, Manual of North American Agromyzidae (Diptera, Schizophora), with revision of the fauna of the " Delmarva " states, ZooKeys 1051, pp. 1-481 : 1

Phytoliriomyza pulchella Spencer

Figs 717-722

Phytobia (Praspedomyza) clara (Melander). Misidentification, in part. Frick 1959: 394.

Pteridomyza hilarella . Misidentification, in part. Spencer 1969: 200 (synonymy of Pteridomyza clara ).

Phytoliriomyza clara (Melander). Misidentification, in part. Spencer and Steyskal 1986b: 159.

Phytoliriomyza pulchella Spencer in Spencer and Steyskal 1986b: 304.

Description.

Wing length 1.5-1.6 mm (♂), 1.8-1.9 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 1.2-2.0. Eye height divided by gena height: 1.9-2.7. Eye bare. Vein r-m near distal 1/3 of cell dm. Frons soft medially.

Chaetotaxy: Two ori with anterior seta reduced to (rarely) absent; two ors. Orbital setulae minute, erect to reclinate, sometimes indistinct, in one row. Postocellar and ocellar setae well-developed, not much longer than tubercle. Four dorsocentrals, one presutural, decreasing in length anteriorly. Acrostichal setulae in four sparse rows. Setae sometimes appearing slightly to very conspicuously thin.

Colouration: Setae dark with orbital setulae, vibrissa and genal and subgenal setae yellow in male, yellow to brownish or brown in female. Head mostly light yellow, whitish below antenna; ocellar tubercle and posterolateral margin of frons (including base of vertical setae) brown with faint stripe sometimes extending to base of posterior fronto-orbital; back of head brown above foramen; female first flagellomere with orange to brownish tint that fades at base. Notum dark brown, covered with short, relatively dense greyish pruinosity; lateral margin of scutum with yellow stripe that is narrower postsuturally, and with brown spot on notopleuron (minute) and postpronotum. Metanotum brown with most of katatergite yellow anteriorly. Pleuron light yellow with most of katepisternum (not reaching base of seta) and meron brown. Halter entirely white. Calypter margin and hairs brown. Legs light yellow with tarsi darker apically. Abdominal tergites brown with lateral margin yellow.

Genitalia: (Figs 717-722 ) Epandrium with irregular row of long tubercle-like setae along posterior margin. Surstylus small and rounded with comb of long tubercle-like setae on inner surface of posterior margin; longer, pointed tubercles on shallow inner-basal process. Subepandrial sclerite U-shaped with one pair of medial setae, irregular lateral sclerotisations and one pair of thin ventral lobes. Hypandrium thin and narrowly arched, with several setae on long inner lobe. Basiphallus dark, not much longer than wide, positioned distally, separate from phallophorus. Mesophallus not evident. Hypophallus long and dark with membranous apex. Distiphallus a single pale tubule along most of length with base dark and heavily sclerotised ventrally; apex bifid, with tubules narrower and strongly divergent. Ejaculatory apodeme large and well-sclerotised stem short and base wide to one side; sperm pump clear.

Hosts.

Unknown - possibly the bracken fern Pteridium aquilinum ( Spencer and Steyskal 1986b), upon which its putative sister species Phytoliriomyza clara is found. Adults have been swept from ferns in Ontario.

Distribution.

Canada: NB*, NL*, NS*, ON, PE*, QC. USA: FL*, MD*, MI*, NH*, NY, VA*.

Type material.

Holotype: USA. NY: Long Island, Farmingdale, 2.vi.1935, Blanton and Borders (HT ♂, CUIC). [Not examined]

Material examined.

Canada. NB: Kouchibouguac N.P. Forest, 46°50'N, 64°55'W, edge, 30.vii-8.viii.2013, O. Lonsdale, CNC316814 (1♀, CNC), NL: St. John's , Agric. Exp. Sta., 30.vii.1967, J.F. McAlpine, CNC391939 (1♂, CNC), NS: CBHNt. Pk., Mackenzie Mt. , 13.vii.1984, PG640848 , CNC479976-479979 (1♂, 3♀, CNC), ON: Griffith, 7mi east, 9.vii.1991, J.R. Vockeroth, CNC479975 (1♂, CNC), Simcoe, 14.vi.1939, G.E. Shewell, CNC391934-391936 (3♀, CNC), Bruce Co., Sauble Falls, ferns in clearing, 28.vii.1977, W. Maddison (2♂ 1♀, ROM), Simcoe, 14.vi.1939, G.E. Shewell, CNC391934-391936 (3♀, CNC), PE: Charlottetown, vii.1967, N.L.H. Krauss (2♀, USNM), QC: Cap Rouge, 7.vii.1953, R. Lambert, CNC391933 (1♂, CNC), Gatineau Pk., 13 km N of Eardley, 24.vi.1988, H.C. Walther, CNC479973, CNC479974 (1♂, 1♀, CNC), Lac Brule, 7.viii.1951, O. Peck, CNC391938 (1♀, CNC) . USA. FL: Mount Pleasant , 1.v.1952, O. Peck, CNC391937 (1♀, CNC), Orange Park, 25.iii.1952, O. Peck, CNC391940 (1♂, CNC), MD: Colesville, 4.vi.1977, W.W. Wirth (1♂, USNM), MI: Hunt Ck., Exp. Sta., nr. Lewiston, 20.vii.1942, C.W. Sabrosky (1♀, USNM), Cadillac, 15.vi.1941, C.W. Sabrosky (1♀, USNM), Hart, 19.vi.1939, C.W. Sabrosky (1?, USNM), Traverse City, 17.vi.1943, C. Sabrosky (1♀, USNM), NH: White Mts., Stinson lake, 23.vii.1961, W.W. Wirth (1♀, USNM), VA: Shenandoah, 14.vi.1982, H. Goulet, big meadows (1♂, USNM) .

Comments.

The similar species Phytoliriomyza pulchella (North America), P. clara (USA) and P. hilarella (Europe) are rediagnosed below. Differences are still comparatively slight, and definitions should be reapproached when more numerous specimens from a broader geographic range are available.

The geographical distribution of Phytoliriomyza clara is uncertain, but at present there is no evidence that it occurs in the Delmarva states. Spencer and Steyskal (1986b) restate Frick’s distribution of California, Washington, Michigan, Tennessee, Maine, and Ontario, and then add Maryland, New Mexico, and Arizona. Of the material examined by Frick, only the type series of Agromyza citreiformis Malloch (= P. clara ) from California can be found, as well as non-type material from Ontario, Michigan, and Maryland, which are here re-identified as P. pulchella . The Ontario and Quebec specimens from the CNC examined by Spencer (1969) as Pteridomyza hilarella are also here determined to be P. pulchella . Oregon* is here added to the distribution of P. clara - otherwise only confidently known from California and Washington. Data are as follows: USA. OR: Curry Co., Cape Blanco, 29.vi.1972, G. Steyskal (4♂, USNM). Locating the remaining specimens examined by Frick will be important in clarifying whether or not this species occurs further to the east. Females from New Brunswick (Kouchibouguac, 1♀, CNC), Nova Scotia (Cape Breton, Glasgow Lake, 2♀, CNC) and British Columbia (Pacific Rim N.P., 1♀, CNC) have a brown first flagellomere and appear to fit the new description of P. clara provided here, but are only tentatively identified as they are mostly in poor condition and lack the additional diagnostic male genitalic features. Melander’s holotype of P. clara at the USNM is largely destroyed, currently represented by only a crumpled wing embedded in glue, part of a leg, and Spencer’s genitalic dissection.

All Canadian specimens of Phytoliriomyza hilarella reported by Spencer (1969) are here determined to be P. pulchella , restricting P. hilarella to Europe. Phytoliriomyza hilarella can be diagnosed as follows: setae dark brown with only orbital setulae sometimes brown; scutum sometimes without yellow lateral regions, being entirely brown; acrostichal setulae sometimes in two to three scattered rows; brownish stripe extending from posterior margin of frons along fronto-orbital plate to anterior ors, but sometimes to anterior or posterior ors along inner margin of fronto-orbital plate; distiphallus strongly sinuate with short apical curve ( Spencer 1976: fig. 532).

Phytoliriomyza clara differs from P. pulchella as follows: male wing length 1.8-2.0 mm; setae not thinner; always one ori (never two); oral setae dark brown (never yellow to brown); first flagellomere pale; hypophallus slightly longer, darker and apically split; phallus slightly longer, more curved and with light pigment on apical cup (Fig. 716 ).

Figures

Figures 717 - 726. Phytoliriomyza pulchella Spencer, male genitalia 717 external genitalia, ventral (subepandrial sclerite shaded) 718 external genitalia, anterior 719 external genitalia, left lateral 720 hypandrium and postgonite, ventral 721 hypandrial complex, left lateral 722 phallus, ventral 723 - 726 P. robiniae (Valley), male genitalia 723 external genitalia, anterior view (broken on slide mount; subepandrial sclerite shaded) 724 ejaculatory apodeme 725 phallus, left lateral 726 postgonite, lateral.

Figures 711 - 716. Phytoliriomyza pilosella Spencer, male genitalia 711 external genitalia, ventral (subepandrial sclerite shaded) 712 external genitalia, left lateral 713 hypandrium and postgonite, ventral 714 hypandrial complex, left lateral 715 phallus, ventral 716 P. clara (Melander), phallus, ventral.