Melanagromyza hieracii Eiseman & Lonsdale, 2021

Eiseman, Charles S., Lonsdale, Owen, Linden, John Van Der, Feldman, Tracy S. & Palmer, Michael W., 2021, Thirteen new species of Agromyzidae (Diptera) from the United States, with new host and distribution records for 32 additional species, Zootaxa 4931 (1), pp. 1-68 : 9-10

Melanagromyza hieracii Eiseman & Lonsdale , spec. nov.

( Figs. 9–12 , 61 , 99–104 )

Holotype. USA. IOWA: Allamakee Co., Fish Farm Mounds WMA, 30.ix.2017, em. spring 2018, J. van der Linden, ex Hieracium scabrum , # CSE4669 , CNC1144040 (1♁).

Etymology. The specific epithet refers to the host plant genus, Hieracium L.

Host. Asteraceae : Hieracium scabrum Michx.

Larval biology. ( Fig. 61 ) The larva bores in the pith of the stem, forming a linear gallery.

Puparium. ( Fig. 12 ) Straw-colored, formed at the end of the larval gallery; rear spiracular horns pronounced, blackish, curved and pointed.

Phenology and voltinism. The holotype emerged after overwintering from a puparium collected on 30 September. All other puparia found at that time in stems of H. scabrum were already empty. Assuming these represented the same species, this suggests either that Melanagromyza hieracii has more than one generation or that adults may be capable of overwintering.

Distribution. USA: IA.

Adult description. Wing length 2.7 mm (♁). Female unknown. Length of ultimate section of vein M 4 divided by penultimate section: 0.7. Eye height divided by gena height: 4.5. First flagellomere small, rounded. Ocellar triangle largely obscured by detritus, appearing to reach past posterior ori. Anterior half of gena slightly angled upwards. Cheek not evident. Clypeus rounded. Eye and head longest above midpoint. Thorax subshining. Body in relatively poor condition; partially collapsed, some setae missing.

Chaetotaxy: Four gracile ori strongly incurved (nearly flat on frons), two strong ors; setae long. Several rows of scattered orbital setulae, as long as eye hairs, erect (inner setulae) to reclinate (outer). Ocellar setae possibly missing, bases obscured. Eye hairs sparse and scattered on dorsal half with dense dorsomedial patch. Anterior of two dorsocentral setae missing, sockets large. Acrostichal setulae in ten irregular rows. Katepisternum with one additional subdominant seta. Mid tibia with two posteromedial setae.

Coloration: ( Figs. 9–11 ) Setae dark brown. Body dark brown, including halter; notum faintly green metallic; abdomen green metallic with blue tint; wing veins brown. Calypter margin and hairs yellow.

Genitalia: ( Figs. 99–104 ) Epandrium with posteroventral spine. Surstylus fused to anteroventral margin of epandrium, relatively narrow and produced with slight posterodistal extension; distal margin with irregular rows of tubercle-like setae. Cercus large and well-developed. Hypandrium broadly rounded basally, with long narrow apical apodeme; inner lobe U-shaped with minute setulae. Phallophorus swollen ventrally, base much narrowed. Basiphallus U-shaped (right side irregularly sclerotized in dissected male), with short gap between apex and mesophallus. Mesophallus swollen cylindrical, narrowest at point of insertion to distiphallus, which is relatively posterobasal. Distiphallus short, globular, with short ventromedial swelling into which mesophallus inserts; basal section mostly made up of posteriorly convergent tubules flanking mesophallus; ventral plate subquadrate, distal margin slightly flared laterally; dorsal chamber shifted distally, widest subapically, with one pair of minutely spinulose internal pads; tubular process narrow, distal half exposed, sinuate when viewed laterally. Ejaculatory apodeme with short dark stem with long lateromedial process; blade narrow with medial rib, margin along one side narrow and irregular (broken?), other side wider and rounded with margin clear; sperm pump with dark transverse bar upcurved at ends.

Comments. This is the first record of a North American Melanagromyza from Hieracium . The European M. oligophaga Spencer includes H. umbellatum L. among its hosts ( Spencer 1990).

Externally, Melanagromyza hieracii is not unlike many other congeners with a metallic green shine (weak on the thorax and with a blue tint on the abdomen), a white calypter, two dorsocentrals and a shallow orbital plate. The key in Spencer & Steyskal (1986) will bring the species to M. longensis Spencer / M. virginiensis Spencer , but unlike these species, it has four ori. The phallus is unlike those of these two species in that the dorsal chamber of the distiphallus is parallel-sided, the lateral margins of the distiphallus are very strongly flared apically, the medial tubule is pronounced and long, far exceeding the apex of the short dorsal chamber, and the mesophallus is strongly shifted basally on the distiphallus. The combination of these phallic features, especially the flared distolateral margins of the distiphallus and the basally shifted mesophallus, is quite unusual for the genus.

Also see comments for Melanagromyza urticae .

Figures

FIGURES 1–12. Figures 1–4: Melanagromyza arnoglossi Eiseman & Lonsdale, spec. nov.; 1: holotype, dorsal; 2: same, head; 3: same, lateral; 4: puparium. Figures 5–8: M. gentianivora Eiseman & Lonsdale, spec. nov.; 5: paratype, dorsal; 6: same, head; 7: same, lateral; 8: puparium. Figures 9–12: M. hieracii Eiseman & Lonsdale, spec. nov.; 9: holotype, dorsal; 10: same, head; 11: same, lateral; 12: puparium.

FIGURES 59–72. Mines and other feeding damage of Agromyzinae on host plants: 59: Agromyza aristata Malloch on Celtis laevigata; 60: Melanagromyza arnoglossi Eiseman & Lonsdale, spec. nov. on Arnoglossum sp.; 61: M. hieracii Eiseman & Lonsdale, spec. nov. on Hieracium scabrum; 62: M. minimoides Spencer on Rudbeckia lacinata; 63: same, section of flower head with puparia inside; 64: Ophiomyia abutilivora Spencer on Abutilon theophrasti; 65: same; 66: Melanagromyza verbenivora Eiseman & Lonsdale, spec. nov. on Verbena stricta, spiral gallery in stem with resulting leaf wilting; 67: same, affected seedhead; 68: Ophiomyia carolinensis Spencer on Symphyotrichum patens; 69: O. cf. frosti Spencer on Lactuca (puparium at upper right); 70: O. rugula Eiseman & Lonsdale, spec. nov. on Baccharis halimifolia; 71: same; 72: same, backlit, showing empty puparium.

FIGURES 99–104. Melanagromyza hieracii Eiseman & Lonsdale, spec. nov., male genitalia; 99: external components, left lateral; 100: same, ventral; 101: hypandrium to epiphallus, ventral; 102: ejaculatory apodeme; 103: phallus, left lateral; 104: same, ventral.