Phytomyza hydrophyllivora, Eiseman & Lonsdale, 2018

Eiseman, Charles S. & Lonsdale, Owen, 2018, New state and host records for Agromyzidae (Diptera) in the United States, with the description of thirty new species, Zootaxa 4479 (1), pp. 1-156 : 75-76

Phytomyza hydrophyllivora spec. nov.

( Figs. 46–47 , 190–191 , 338–342 )

Holotype. OHIO: Delaware Co., Sunbury, Monkey Hollow Rd. , 2.viii.2016, em . 25.viii.2016, C.S. Eiseman, ex Hydrophyllum canadense , #CSE2938, CNC654472 (1♂).

Paratypes. MASSACHUSETTS: Berkshire Co., Tyringham , 11.ix.2015, em . 19.iv.2016, C.S. Eiseman, ex

Hydrophyllum virginianum , #CSE2405, CNC634807 (1♂ [illustrated, not fully developed]); TENNESSEE: Davidson Co., Oak Hill, Radnor Lake , 36.061386, -86.802539, 22.viii.2017, em . 21.ix.2017, C.S. Eiseman, ex Hydrophyllum canadense , #CSE4299, CNC939957 (1♂).

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

Hosts. Boraginaceae : Hydrophyllum canadense L., H. virginianum L.

Leaf mine. ( Figs. 190–191 ) Upper surface; greenish to pale brown; initially narrow and linear, expanding to a blotch that occupies most or all of a Hydrophyllum virginianum leaf segment. Feeding lines are sometimes present. Black frass is scattered throughout in small grains and irregular lumps. On H. canadense , the larva cuts a crescentshaped exit slit in the lower epidermis.

Puparium. ( Fig. 46 ) The puparia of our three reared specimens were yellow to yellowish-brown and were found protruding from their mines. The one on Hydrophyllum virginianum was loosely attached to the tip of a leaf serration, with approximately the posterior eighth still inserted between the leaf epidermises ( Fig. 191 ). In the H. canadense mine from Ohio, slightly less than the posterior half of the puparium was concealed by the leaf flap produced by the cutting of the exit slit, and in the one from Tennessee, about a third of the puparium was exposed. We have just once found a mine on H. virginianum in Massachusetts containing a larva; this formed a yellow puparium within the mine but no adult ever emerged. In Ohio we have found numerous mines on H. canadense with a yellow to brown puparium formed entirely within the leaf, on the lower surface (but still with an exit slit cut by the larva). Collections of these have yielded 22 parasitoid wasps ( Eulophidae and Braconidae ) and no flies.

Distribution. USA: MA, OH, TN. Spencer & Steyskal’s (1986) unidentified leaf mine #10, from Wisconsin, appears to represent this species.

Adult description. Wing length 2.1mm (♂). Female unknown. Eye height divided by gena height: 9.1. First flagellomere small and rounded, with small, ill-defined anteromedial tuft of slightly longer hairs. Notum pruinose. Vein dm-cu absent.

Chaetotaxy: Two ors (posterior seta ½–4/5 length anterior ors), two ori (anterior seta approximately 4/5 length).

Coloration: ( Fig. 47 ) Setae dark brown. Head brown, slightly darker on orbital plate, especially to eye margin, and slightly darker in posterolateral region of frons around vertical setae; ocellar spot slightly larger than tubercle, ovate/semicircular, largely confluent with posterior margin of frons; back of head, clypeus, palpus, antenna and face dark brown. Body faintly brownish pruinose, denser and more coppery on thorax, especially on scutum and scutellum, which bear broad bluish patches; postpronotum, notopleuron and supra-alar region paler with yellowish patches. Calypter white, hairs light brown. Haltere white. Legs dark brown with apices of femora narrowly light yellow, with spot on apex of fore femur as long as wide, and tibiae and tarsi light yellow to yellow.

Genitalia: ( Figs. 338–342 ) Surstylus small, rounded, with inner-marginal setae; posterior margin of epandrium with small, flat plate projecting medial to surstylus. Hypandrium thick, broadly rounded. Postgonite simple, with one medial seta and one distal socket. Phallophorus flanked by one pair of pale, broad, flat band-like sclerites; dorsally fused to right sclerite of basiphallus. Basiphallus composed of two sclerites, each medially broadened and with dark sclerotized strip; left sclerite with apical swelling, base wrapped around shaft. Hypophallus with one pair of dark lateral sclerites that are several times longer than wide, basally narrowed and curved anteriorly; each half produces a thin sheet subapically, these fusing medially to form a narrow membranous anteromedial process; with thick, convoluted ventromedial tubule that is lightly sclerotized medially and flagellate apically. Paraphallus dark, as long as basal arm of hypophallus, and apically tapered and fused to ventromedial surface of mesophallus. Mesophallus twice as thick as duct, cylindrical, pigmented, with ventromedial carina; fused to distiphallus. Distiphallus divided into two narrow tubules partially joined at base that are diverging and slightly downturned; inner-medial surface with slightly raised plate.

Comments. See comments for Phytomyza confusa .

Figures

FIGURES 44–50. Figures 44–45. Phytomyza hatfieldae spec. nov.; 44: puparia; 45: adult female. Figures 46–47: P. hydrophyllivora spec. nov.; 46: puparium; 47: adult male. Figure 48: P. loewii Hendel, puparium. Figures 49–50: P. palustris spec. nov. 49: adult male; 50: empty puparium.

FIGURES 189–199. leaf mines; 189: Phytomyza hatfieldae spec. nov. in Osmorhiza claytonii; 190: P. hydrophyllivora spec. nov. in Hydrophyllum canadense; 191: P. hydrophyllivora in Hydrophyllum virginianum (yellow puparium at tip of leaf serration, upper right); 192: P. linnaeae (Griffiths) in Linnaea borealis (transmitted light); 193: P. loewii Hendel in Clematis virginiana; 194: P. minuscula Goureau in Thalictrum pubescens; 195: P. omlandi Scheffer & Lonsdale in Gelsemium sempervirens; 196: P. palmeri spec. nov. in Symphoricarpos orbiculatus (transmitted light; puparium at upper left); 197: P. palustris spec. nov. in Micranthes pensylvanica; 198: same, five brown puparia in blisters on lower leaf surface (whitish object along left side of midrib is a coniopterygid cocoon); 199: P. penstemonis Spencer in Penstemon digitalis.

FIGURES 338–342. Phytomyza hydrophyllivora spec. nov., male genitalia; 338: external components, posterior; 339: postgonite, left lateral; 340: hypandrium, ventral; 341: phallus, ventral; 342: phallus, left lateral.