Aulagromyza tridentata (Loew)

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

Aulagromyza tridentata (Loew)

Figs 89 , 442-445

Agromyza tridentata Loew, 1858: 76. Hendel 1932: 295.

Paraphytomyza tridentata . Spencer 1972: 67, 1976: 323.

Aulagromyza tridentata . von Tschirnhaus 1991: 305; Scheffer et al. 2007: 771; Papp and Černý 2016: 349.

Description

(Fig. 89 ). Wing length 1.6 mm (♂), 2.2 mm (♀). Vein dm-m absent. Eye height divided by gena height: 1.8-2.1. Gena very high and broadly rounded. Fronto-orbital plate projecting, but not as prominent as broad, rounded parafacial and cheek. Ocellar triangle slightly larger than tubercle, weakly defined, corners rounded. Vein M1+2 spectral and close to wing apex, M4 and CuA+CuP similarly weak. Body with faint greyish pruinosity that is slightly denser on thorax.

Chaetotaxy: Two ori; two ors (possibly three ors and one ori). Postocellar and ocellar setae well-developed. Orbital setulae few, minute, slightly reclinate. Four dorsocentrals; one presutural, length decreasing anteriorly. Four rows of acrostichal setulae, becoming two irregular rows posteriorly.

Colouration: Setae light yellow to slightly brownish, with notal setae brown to black in female and sometimes browner posteriorly on notum in male. Body predominantly lemon yellow; ocellar tubercle brown; small brown spots sometimes present lateral to vertical setae; back of head with broad brown stripe extending from foramen; mediotergite and sometimes anterior region of anatergite brown; scutum with medial stripe ending before posterior dorsocentral, fused anteriorly (examined European specimen) or completely to one pair of posteriorly narrowing intra-alar stripes that reach neither anterior nor posterior margins; pleuron with small light greyish brown spots ventrally on katatergite and meron. Halter yellow. Calypter white. Wing veins light yellow.

Genitalia: (Figs 442-445 ) Epandrium pale and broad. Surstylus large, broadly rounded and twisted so that setulose inner face visible posteriorly. Subepandrial sclerite subrectangular, flat, weakly sclerotised and bare. Hypandrium small, thin, and broadly rounded; inner lobe with two setae. Postgonite large, broad, and thick with flat dorsum, inner-posterior ridge, long posterobasal extension, and pointed apical process on inner face. Phallophorus fused to base of single plate of basiphallus, which is membranous on right margin and bifid apically. Distiphallus membranous and flagellate; paraphallus distinct, narrow, and medially curved. Ejaculatory apodeme small and pale past base and with apex clear.

Host.

Salicaceae - Salix sp.

Distribution.

USA: CO, DE*, MD*. Europe, extending eastward to Kazakh Republic.

Type material.

Holotype: Poland. Poznan area (ST?, ZIL). [Not examined]

Material examined.

GERMANY. Berlin, Dahlem , 19.v.1953, mine an Salix alba , No. 5941, CNC165187 (1♂, CNC) . USA. DE: Bridgeville , 14.vii.1960, willow, P. Burbutis (2♂ 2♀ [with mined leaf], USNM), Bridgeville, 15.vi.1960, willow leaf miner, P.Burbutis (1♂, USNM), MD: Montgomery Co., Colesville, 26.vi.1977, Malaise trap, W.W. Wirth (1♀, USNM) .

Comments.

This is the second record of Aulagromyza tridentata in the United States, with Scheffer et al. (2007) rearing material from Salix in Colorado. European specimens of A. tridentata differ in having the notal patch more conspicuously divided into bands. These uncommon Salicaeae-feeding Aulagromyza differ from Nearctic congeners in being lemon-yellow with pale setae, and are likely to be mistaken for paler Phytoliriomyza or a species of Liriomyza . The only other previous Nearctic records of this group were Ontario specimens of A. populicola (Walker) reared from Populus deltoides in Ottawa ( Frick 1959; Spencer 1969) and two females from Oklahoma reared from the same species ( Eiseman and Lonsdale 2018). Aulagromyza populicola is a vittate species highly similar in appearance to A. tridentata , but it has the scutal pattern brownish orange (not darker brown), and the phallus is more extensively sclerotised and structured apically ( Spencer 1976: figs 579, 580).

The identity of this species was determined by comparison to a description and illustrations of Aulagromyza tridentata presented by Spencer (1976). A similar description for A. tridentata appears in Papp and Černý (2016), but the genitalic illustration does not match; an illustration approximating the expected genitalic morphology for this species is provided for the species A. populicola (Walker). The genitalic and external morphology of A. populicola was verified from a series collected in Ottawa that was reported in Spencer (1969).

Figures

Figures 84 - 91. Amauromyza flavifrons (Meigen), head 84 anterior 85 lateral 86, 87 Amauromyza karli (Hendel), head 86 dorsal 87 lateral 88 Aulagromyza nitida (Malloch), male, lateral 89 Aulagromyza tridentata (Loew), male, lateral 90, 91 Calycomyza enceliae Spencer, male, on bush sunflower (R. Hemberger - California, Irvine).

Figures 442 - 445. Aulagromyza tridentata (Loew), male genitalia 442 hypandrium and postgonite, ventral 443 external genitalia, anterior (subepandrial sclerite shaded) 444 hypandrial complex, left lateral 445 phallus, ventral.