Phytomyza crassiseta Zetterstedt, 1860

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

Phytomyza crassiseta Zetterstedt

Figs 134 , 766-770

Phytomyza crassiseta Zetterstedt, 1860: 6469. Melander 1913: 271; Hendel 1935: 387; Frick 1959: 427; Block 1969: 357; Spencer 1976: 408, 1990: 224; Spencer and Steyskal 1986b: 185; Glesener and Tilman 1978: 662; Černý 2018: 132; Scheffer and Lonsdale 2018: 88; Eiseman and Lonsdale 2018: 71; Papp and Černý 2020: 335; Černý et al. 2020: 216.

Phytomyza veronicae Brischke, 1881: 271 [preoccupied by Kaltenbach]. Hendel 1935 [synonymy].

Description

(Fig. 134 ). Wing length 2.1 mm (European ♂), 2.3 mm (WA ♂), 1.6-2.3 mm (♀). Vein dm-m absent. Eye height divided by gena height: 1.9-4.0. Arista laterally flattened, tapered on apical 1/2. First flagellomere slightly longer than high, broadly rounded apically, profile sometimes slightly subrectangular; hairs slightly longer than average, relatively dense. Fronto-orbital plate projecting anteriorly, and parafacial narrow but sometimes also prominent when viewed laterally. Ocellar triangle slightly larger than tubercle, sometimes subcircular. Cheek pronounced.

Chaetotaxy: One ori in female, two in male; two ors. Ocellar and postocellar setae fine and sometimes longer than fronto-orbitals. Four dorsocentrals, decreasing in length anteriorly. Two sparse rows of acrostichal setulae anteriorly. Intra-alar setulae strongly reduced to one or a few setulae anteriorly.

Colouration: Body with faint greyish pruinosity evident on pigmented regions, which is denser on thorax, especially on dorsum. Head light yellow with frons sometimes slightly darker; clypeus, palpus and first flagellomere dark brown; scape, pedicel, ocellar triangle, back of head, posteroventral margin of gena and posterolateral corner of frons lateral to base of inner vertical seta brown; fronto-orbital plate with faint, fine whitish pruinosity that appears grey on an angle (as in some Phytoliriomyza ); fronto-orbital plate with minute to large spots around bases of fronto-orbitals that are sometimes connected to faint brownish grey line along eye margin that uncommonly extends from dark posterolateral corner of frons. Thorax dark brown with grey pruinosity. Halter white. Calypter entirely yellowish white. Legs mostly dark brown, with apex of femora yellow for length greater than width of femur apex, and fore coxa variably yellow, but always with at least apex yellow and base dark. Abdomen brown; side of tergites yellow in female.

Genitalia: (Figs 766-770 ) Epandrium rounded, fused to small, setose surstylus. Cercus small, outer-dorsal margin ill-defined. Hypandrium broadly rounded with wide apical apodeme; inner lobe discrete, with two setae, connected via weak lateral sclerotisation and oblique distal band. Postgonite well-developed with strong apical arch. Basiphallus with two ill-defined, dextrally twisted bands that are each weakly defined and dorsally fused, forming a broad transverse apical plate. Hypophallus membranous, small, concave. Paraphalli lateral, asymmetrical, right sclerite largely desclerotised except at base, and left sclerite large, weakly sclerotised and clavate with basal stem abruptly narrowed; with one pair of darker inner accessory sclerites that flank mesophallus and are connected to distiphallus ventrally by membrane. Mesophallus (interpreted as thicker basal section of distiphallus connected to narrower ejaculatory duct) not readily differentiated from distiphallus, tubular, clear. Distiphallus tubular, mostly clear, slightly flared at opening, with band-like medial sclerotisation with ventral suture and narrow basomedial stem.

Hosts.

Plantaginaceae - Hebe ( Spencer and Steyskal 1986b), Veronica ( Benavent-Corai et al. 2005).

Distribution.

Canada. ON*, QC (leaf mine). USA: CA, ID, IN*, MA, MD, ME (leaf mines), NC, NJ*, NY, PA, VA, WA, WV. Argentina, Chile, Europe, Japan, Turkey, Russia ( Papp and Černý 2020).

Type material.

Holotype [ Phytomyza crassiseta ]: Sweden. Skane: Kingsmarken, Lake Ringsjon (HT ♀, ZIL). [Not examined]

Holotype [ Phytomyza veronicae ]: Poland. Gdansk [as “Danzig”] (type data unknown). [Not examined]

Material examined.

Canada. ON: Wellington Co., Smith Property Trail nr. Arkell, 43°33'N, 80°11'W, 23.vi.2015, O. Lonsdale, CNC441143 (1♀, CNC), Halton, Norval, 5.vi.2008, on Veronica spicata , D. Cheung (1♀, photo voucher - Fig. 134 ). Chile. Estero la Jaula Curico, 1600 m, Nothofagus, i.1964, L. Pena, CNC480097 (1♀, CNC), Piscicultura Aconcagua, 1600 m, 11.xi.1963, L. Pena, CNC480096 (1♀, CNC). England. Chippenham Fen, Cambs., 20.ix.1958, [K.A. Spencer], CNC480093 (1♂, CNC), [illegible] Head, S Devon, 7.ix.1954, [K.A. Spencer], Veronica em. 29.ix.1954, CNC480094 (1♀, CNC). Germany. Saxony-Anhalt: Tilleda, Sud Kyffhausse, x.1962, I. Michel, mine an Veronica "Z No. 1962 Hering: Z, CNC480095 (2♀, CNC). USA. ID: Collins, A.L. Melander (1♀, USNM), IN: Lafayette, J.M. Aldrich, 10.vi.1915 (1♀, USNM), 6.vii.1915 (1♀, USNM), Michigan City, 29.vi.1915, J.M. Aldrich (1♀, USNM), MA: Franklin Co., Sunderland, Falls Rd., 13.vii.2012, em. 23.vii.2012, C.S. Eiseman, ex Veronica officinalis (1♀ [with puparium], CNC), Hampshire Co., Pelham, 88 Arnold St., 25.vi.2014, C.S. Eiseman, ex. Veronica chamaedrys em. 2-16.vii.2014, #CSE1148, CNC384850-384862 (13♀, CNC), MD: Glen Echo, 29.v.1919, J.M. Aldrich (1♀, USNM), Montgomery Co., Colesville, 14.vi.1976, Malaise trap, W.W. Wirth (2♀, USNM), Bethseda, G.C. Steyskal, 3.vi.1972 (1♀, USNM), 16.vii.1967 (1♀, USNM), 4mi SW of Ashton, 25.iv.1987, G.F. and J.F. Hevel (1♀, USNM), Forest Glen, 25.vi.1967, W.W. Wirth (1♀, USNM), P.G. Co., Camp Springs, G.F. Hevel, Malaise trap, 9.vii.1979 (1♀, USNM), 8.vii.1979 (2♀, USNM), 16.vii.1979 (1♀, USNM), Carroll Co., Eldersburg, 2.vi.1985, W.E. Steiner and J.E. Lowry (1♀, USNM), NC: Chatham Co., Haywood, 5.vi.1986, G.C. Steyskal (3♀, USNM), Macon Co., Highlands, Lake Ravenel, Malaise trap, W.W. Wirth, 14.vi.1986 (1♀, USNM), 19.vi.1986 (1♀, USNM), Durham Co., Durham, Pelham Rd., 20.iv.2016, T.S. Feldman, Veronica peregrine , em. 14-16.v.2016, #CSE2461, CNC634800-634803 (4♀, CNC), Scotland Co., Laurinburg, St. Andrews University, 2.v.2016, T.S. Feldman, Veronica arvensis , em. 17.v.2016, #CSE2468, CNC634782 (1♀, CNC), Durham Co., Durham, Duke University, 23.v.2016, T.S. Feldman, Veronica persica , em. 29.v-3.vi.2016, #CSE2517, CNC654295-654302 (8♀, CNC), NJ: Morristown, 9.iv.1922, A.H. Sturtevant (1♀, USNM), NY: Bear Mt., 8.vi.1918, A.H. Sturtevant (1♀, USNM), PA: Dubois, 3.ix.1927, A.L. Melander (1♀, USNM), VA: Glencarlyn, 30.v.1925, J.R. Malloch (1♀, USNM), Arlington, 18.v.1982, F.C. and B.J. Thompson (1♀, USNM), Alexandria, 11.vi.1952, W.W. Wirth (1♀, USNM), Pulaski, 7.v.1979, G. Steyskal (2♀, USNM), Fairfax Co., Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, 10-17.v.2007, D.R. Smith (1♀, USNM), WA: Mt. Constitution, 22.vii.1909 (1♀, USNM), Chehalis, 25.viii.1911, A.L. Melander (1♀, USNM).

Comments.

The laterally flattened arista and unusual genitalia of Phytomyza crassiseta readily differentiate it from other Delmarva species, but diagnosis elsewhere is more difficult where similar characters occur in a number of related species that require further study to refine diagnostic characters. These include the Quebec species P. pedicularicaulis Spencer (on Pedicularis , Orobanchaceae ) ( Spencer 1969: figs 477, 478) and the British Columbian species P. superba Spencer (host unknown) ( Spencer 1969: figs 515, 516). Other related species, including the Palearctic Phytomyza affinis Fallén, the Albertan P. banffensis Spencer, and a number of more southern Nearctic species (Spencer and Steyskal 1986), are superficially quite similar but have a filamentous arista.

Collection records show males of Phytomyza crassiseta to be very rarely encountered in the New World (an English male is illustrated here), where the species has likely been introduced, with females suspected to reproduce parthenogenetically ( Spencer and Steyskal 1986b). In Europe, males are also uncommon towards the north, but are found in numbers equal to those of females in the Mediterranean region ( Glesener and Tilman 1978). The cytology of this species was examined by Block (1969), who noted that the only other known parthenogenetic species in the family was P. plantaginis .

Figures

Figures 131 - 138. 131 Phytomyza (Napomyza) lateralis Fallen, female and puparium 132 Phytomyza compta (Spencer), male holotype, lateral 133 Phytomyza nervosa Loew, lateral, with detail of proclinate orbital setulae (arrow) 134 Phytomyza crassiseta Zetterstedt, female (D. Cheung - Ontario) 135 Phytomyza sp., female (S. A. Marshall - Hornings Mills) 136 Phytomyza sp., female (B. Dupree - Georgia, Atlanta) 137 Phytomyza sp., female (K. Hall - Washington, Lacey) 138 Phytomyza bicolor Coquillett, female on Caltha palustris (S. A. Marshall - Ontario, Spring Creek).

Figures 766 - 770. Phytomyza crassiseta Zetterstedt, male genitalia 766 external genitalia, posterior 767 hypandrium, ventral 768 postgonite, lateral 769 phallus, ventral 770 phallus, left lateral.