Phytomyza salviarum, Eiseman & Lonsdale, 2019

Eiseman, Charles S. & Lonsdale, Owen, 2019, New State and Host Records for Agromyzidae (Diptera) in the United States, with the Description of Ten New Species, Zootaxa 4661 (1), pp. 1-39 : 20-21

Phytomyza salviarum spec. nov.

( Figs. 32, 33 , 63 , 110–115 )

Holotype. TEXAS: Edwards Co., 1.3 mi NW of Camp Wood, 16.iii.2017, em. 28.iii–3.iv.2017, C.S. Eiseman, ex Salvia ballotiflora , #CSE3315, CNC941268 (1³).

Paratypes. Same data as holotype, CNC941262–941267 (4³, 3♀) ; same except ex Salvia farinacea , em. 30.iii.2017, #CSE3335, CNC941271 (1³).

Etymology. The specific epithet combines the genus of the host plants, Salvia L., with the genitive plural ending - arum.

Hosts. Lamiaceae : Salvia ballotiflora Benth. , S. farinacea Benth. ; a mine on S. roemeriana Scheele containing an empty puparium was found at the type locality.

Leaf mine. ( Fig. 63 ) A serpentine linear mine on the upper surface; brown with narrow whitish margins, becoming greenish at the end as it transitions to the lower surface. The black frass is deposited in grains and strips.

Puparium. ( Fig. 33 ) Whitish; formed within the leaf, on the lower surface, with the anterior spiracles projecting through the epidermis.

Distribution. USA: TX.

Adult description. Wing length 2.0– 2.1 mm (³), 2.2–2.3 mm (♀). Crossvein dm-cu absent. Eye height divided by gena height: 3.5–4.4. First flagellomere small, rounded. Orbital plate slightly prominent anteriorly (lateral view). Ocellar triangle rounded, small, not much larger than tubercle. Cheek narrow, not prominent. Body with light pruinosity that is denser and grayer on notum.

Chaetotaxy: Two ors, one ori; ori and anterior ors closely spaced near anterior margin of frons. Few orbital setulae. Four dorsocentral setae, decreasing in length anteriorly, with fourth seta close to third and approximately ¼ length of first. Acrostichal seta absent. Acrostichal setulae in four irregular rows to level of second dorsocentral.

Coloration: ( Fig. 32 ) Setae black. Head mostly light yellow; antenna, ocellar triangle, posterior margin of frons, posterolateral corner of frons to base of inner vertical seta, back of head, clypeus and palpus dark brown; dark brownish-black stripe across front of head that includes lunule, anterolateral corner of frons to level of ori and dorsal half of face and parafacial. Thorax dark brown with dense gray pruinosity that has bluish tinted regions and coppery region posteromedially on scutum and scutellum; scutum with lateral light yellow stripe that is narrower postsuturally and excludes dark spot on postpronotum; anepisternum with dorsal light yellow stripe that is ¼ height of sclerite anteriorly and 1/3 height posteriorly. Wing veins brown with base of costa and stem vein light yellow. Calypter margin and hairs light yellow. Legs paler brown than thorax, apex of fore femur narrowly light yellow and base of fore and mid tibiae narrowly light yellow. Abdomen paler brown than thorax; lateral margin of tergites 1–6 light yellow with stripe visible dorsally.

Genitalia: ( Figs. 110–115 ) Epandrium with eight short, tubercle-like setae along inner posteroventral margin; inner-medial margin with flat, ventrally pointed process positioned anterolateral to cercus. Surstylus rounded, fused to epandrium, inner surface bare centrally. Cercus with one pair of longer apical setae. Hypandrium thin, narrowly U-shaped, with narrow inner lobe bearing one seta. Pregonite well-developed, slightly upcurved and darker apically; dorsal arm band-like, embedded in membrane, with medial fossa. Phallophorus shallow ventrally, twisted, with long dorsal plate-like extension wrapping around right surface of shaft. Basiphallus with paired sclerites long, narrow, right sclerite wrapping dorsally at base. Hypophallus composed of one pair of flat, apically converging bands that are twisted near apex. Paraphallus fused to apex of basiphallus, directed apically; length three times width at middle, narrowing to base, slightly truncated apically with anterodorsal sclerotized patch extending from margin; confluent with apical membranous sac with small, irregular ventromedial sclerotized spot. Mesophallus not evident. Distiphallus with main branch receiving duct angled ventrally, almost resting between arms of hypophallus, shape linear with apex slightly paler, flattened and widened; base projecting dorsally as strongly curved, T-shaped plate positioned between paraphalli. Ejaculatory apodeme small, blade minute, one side of stem better sclerotized; sperm sac small with minute sclerotized patch; base of duct nearly as wide as sac.

Comments. Phytomyza salviarum is sister to P. verbenae Eiseman & Lonsdale , a species of uncertain placement that also feeds on a host in the order Lamiales : Verbena (Verbenaceae) . The tubercle-like setae on the posteromedial margin of the epandrium and the underlying pointed lobe are unique. Also characteristic are the following: a light yellow head with a black antenna and transverse black stripe on the lunule and face, a dark abdomen that is widely light yellow laterally, two long apical setae on the male cercus, a band-like dorsal arm on the pregonite, and a highly derived phallus—the phallophorus is reduced on the ventral margin and strongly produced along the right lateral surface of the shaft; the plates of the basiphallus are medially bowed; the hypophallus has one pair of sclerites that are converging and apically flattened; the paraphallus is small, linear, fused to the basiphallus and with an illdefined sclerotized extension on the large, empty apical membranous chamber; the distiphallus is narrow, directed distoventrally, apically flared and with a curved dorsobasal T-shaped plate-like extension above the insertion point of the ejaculatory duct.

Phytomyza verbenae differs from its sister taxon in being slightly larger (2.3 mm ³, 2.7 mm ♀), and in the fol- lowing characters: there are two ori, the female first flagellomere is enlarged, there is a setula-like fifth dorsocentral anteriorly, the phallophorus is fused to the right plate of the basiphallus, the apex of the lateral sclerite of the hypophallus is broadly swollen and rounded, the paraphallus is quadrate with the distal sclerotization irregular and pitted, and the apical membranous lobe on the phallus is narrower.

Figures

FIGURES 27–33. Figs. 27–28: Phytomyza mimuli (Spencer); 27: adult male; 28: puparium. Fig. 29: P. nemophilae spec. nov., male. Figs. 30–31: P. prava Spencer; 30: adult female; 31: puparium. Figs. 32–33: P. salviarum spec. nov.; 32: adult female; 33: empty puparium removed from leaf mine.

FIGURES 57–63. leaf mines: 57: Phytomyza davisii (Walton), on Ranunculus recurvatus (mines containing feeding larvae); 58: the same mines, complete and vacated; 59: P. mimuli (Spencer), on Phacelia crenulata (reflected light); 60: same (transmitted light); 61: P. nemophilae spec. nov., on Nemophila parviflora; 62: P. prava Spencer, on Anemone canadensis; 63: P. salviarum spec. nov., on Salvia ballotiflora.

FIGURES 110–115. Phytomyza salviarum spec. nov., male genitalia; 110: external components, posterior; 111: postgonite, left lateral; 112: hypandrium, ventral; 113: ejaculatory apodeme; 114: phallus, ventral; 115: phallus, left lateral.