Ophiomyia osmorhizae, 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 : 7-8

Ophiomyia osmorhizae spec. nov.

( Figs. 5 , 82–86 )

Holotype. IOWA: Winneshiek Co., Falcon Springs Wildlife Management Area , early spring 2017, em. 1.v.2017, J. van der Linden, ex Osmorhiza , #CSE3775, CNC1144021 (1³).

Paratype. Same data as holotype except em. 9.v.2017, #CSE3776, CNC940113 (1♀) .

Etymology. The specific epithet refers to the host plant, Osmorhiza Raf.

Host. Apiaceae : Osmorhiza Raf.

Larval biology. The larva forms a linear stem mine, causing evident discoloration when the plant is alive but not discernible in dead, overwintered stems.

Puparium. ( Fig. 5 ) Black; formed just beneath the stem epidermis. Linden (2017) reports that puparia are consistently found just below the first branches.

Distribution. USA: IA.

Adult description. Wing length 2.1 mm (³), 2.2 mm (♀). Length of ultimate section of vein CuA 1 divided by penultimate section: 0.9. Eye height divided by gena height: 6.4–7.5. Eye slightly oblique, but still relatively round. Arista short pubescent. Ocellar triangle nearly reaching level of posterior ori. Ocellar plate narrow. Facial carina well-developed, medially with subshining, ovate bulb; carina above bulb as wide as bulb, with wide medial groove continuing onto lunule. Lunule height subequal to width of carina dorsally. Genal process nearly as long as high, forming an approximate 60° angle; anterior point slightly produced, narrow. Clypeus with arms bowed inwards anteriorly, meeting at small subquadrate anteromedial extension that is shallowly concave anteriorly and with one pair of minute anterolateral points. Male holotype head partially collapsed.

Chaetotaxy: Three ors in male, two in female; two ori; setae slightly decreasing in length anteriorly. Postvertical and ocellar setae subequal to posterior ors. Two dorsocentral setae, anterior seta slightly shorter. Acrostichal setulae in eight rows. Male fasciculus well-developed, strongly upcurved. Mid tibia without medial setae.

Coloration: Setae black. Body dark brown, including halter. Ocellar triangle and ocellar plate paler brown. Calypter, including margin, light brown; hairs dark brown. Abdomen without metallic shine.

Genitalia: ( Figs. 82–86 ) Epandrium well-developed, fused to anteriorly angled surstylus. Surstylus small, rounded, subquadrate, with several irregular rows of tubercle-like setae on inner surface. Hypandrium subtriangular with pointed inner-basal process, and slightly produced, rounded apex. Phallophorus with base darker and shorter; apex higher, paler and laterally compressed. Basiphallus with short, very ill-defined left lateral arm that is basally fused to longer, apically truncated right lateral arm that nearly reaches level of mesophallus. Mesophallus narrow, cylindrical, inserted ventromedially into larger distiphallus; base of mesophallus approximately level with base of distiphallus. Distiphallus relatively large and complex in structure, with boundary between basal and distal sections not evident when viewed laterally, but relatively well-bounded by transverse sclerotization past mesophallus when seen ventrally; distiphallus as a whole broadly open dorsally, forming an irregular bowl with margin bordered by minute bumps, and internally with dark irregular textured tube directed distally, one broad apically curved shelf emerging medially, and several small, curved floating sclerites positioned basomedially; basal section broadest medially where internal surface is densely covered by minute spinules, including one larger tuft on right lateral surface; sides with one pair of broad, bulging pouches with minute irregular texturing; apex of basal section narrower and rounded; distal section of distiphallus narrower, slightly curved to left, broadest basally, weakly differentiated into two halves ventrally with shallow bumps and points on inner surface. Ejaculatory apodeme with strongly arched base, dark short stem with small process to one side, and pale blade with dark medial rib and irregular distal sclerotizations; sperm pump with dark transverse bar.

Comments. The phallus of Ophiomyia osmorhizae is distinct, being large with strong internal processes, texturing and ridges, and should not be confused with that of other taxa. This species will key to O. delecta Spencer / O. asymmetrica Spencer in Spencer & Steyskal (1986) , but the genitalia will readily differentiate it.

This is the first record of an Ophiomyia from Osmorhiza .

Figures

FIGURES 1–5. Figs. 1–2: Agromyza princei spec. nov.; 1: adult male; 2: puparium. Figs. 3–4: Ophiomyia antennariae spec. nov.; 3: adult male; 4: puparium. Fig. 5: Ophiomyia osmorhizae spec. nov., puparia.

FIGURES 82–86. Ophiomyia osmorhizae spec. nov., male genitalia; 82: external components, left lateral; 83: hypandrium and postgonite, ventral; 84: ejaculatory apodeme; 85: phallus, ventral; 86: phallus, left lateral.