Melanagromyza palmeri, 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 : 17-18

Melanagromyza palmeri spec. nov.

( Figs. 234–239 )

Holotype. OKLAHOMA: Payne Co., Mehan , 36.014339° N, 96.996744° W, 18.ix.2016, em. 7.x.2016, M.W. Palmer, ex Helianthus annuus , #CSE3143, CNC668291 (1♂) .

Etymology. This species is named for Michael W. Palmer, botanist, who reared the type specimen as well as a number of other specimens used in this study.

Host. Asteraceae : Helianthus annuus L.

Larval biology. The larva is a stem borer or possibly a root borer. The adult emerged in a bag containing stems, which included a portion of the taproot, collected in a failed attempt to rear larger stem-boring larvae (probably coleopteran or lepidopteran). No feeding trace of the larva was observed (M. Palmer, in litt.).

Distribution. USA: OK.

Adult description. Wing length 2.5mm (♂). Female unknown. Length of ultimate section of vein CuA1 divided by penultimate section: 0.7. Eye height divided by gena height: 5.4. First flagellomere rounded, small, slightly shorter than high. Arista pubescent. Orbital plate slightly visible anteriorly, prominently bulging and downturned between widely spaced anterior and posterior ori. Facial carina present, shallow. Lunule nearly as wide as high. Ocellar triangle longer than wide, reaching level of anterior ors. Orbital plate widest at level of of anterior ors, 0.3 times width of frons. Narrow cheek visible.

Chaetotaxy: Two ors, two ori; postitoned along inner margin of orbital plate; setae missing from specimen, excluding strongly inclinate anterior ori, which is distantly spaced anteriorly from remaining dorsomedially clustered fronto-orbitals, typical of M. virens species group. Orbital setulae in several scattered rows, erect to lateroclinate; not longer than eye setulae, which are sparsely arranged except for dense dorsomedial cluster. Ocellar seta thinner than, and approximately 4/5 length of postvertical seta. Apparently two pairs of dorsocentral setae (only first seta on left side remaining). Approximately ten rows of acrostichal setulae. Apical scutellar setae short, apex not exceeding that of lateral scutellar. Fore femur with row of long posterodorsal setae. Anepisternum with enlarged setae posteriorly. Katepisternum with strong dorsal setae comparable in length to standard single seta. Mid tibia with two lateromedial setae.

Coloration: Setae black. Body dark brown; notum and abdomen with metallic green shine with coppery tint; calypter white.

Genitalia: ( Figs. 234–239 ) Epandrium with posteroventral spine. Surstylus fused to epandrium, small, triangular, with several rows of tubercle-like setae along inner-distal and posterior margins, with apical tubercles long, narrow, posteriorly directed. Hypandrium stout, subtriangular, with long terminal apodeme. Phallophorus broad, short. Basiphallus U-shaped, short, base and irregular apex of approximately equal distance from phallophorus and distiphallus (respectively). Mesophallus tubular, lightly pigmented, inserted ventromedially into distiphallus. Distiphallus stout, well-developed, sides (seen ventrally) subparallel with midpoint slightly bulging; in lateral view, basal section large, nearly as high as long and as long as dark, flattened distal section; with spinulose inner process; with one pair of stout ventrolateral tubules flanking mesophallus. Ejaculatory apodeme welldeveloped with blade weakly sclerotized excluding medial rib, laterobasal process strong; sperm pump with strong transverse sclerite ventrally that partially extends along duct base.

Comments. Melanagromyza palmeri belongs to the M. virens species group, most obviously evidenced by the frons, where a strong anterior bulge widely separates the anterior ori from the remaining posteromedially clustered fronto-orbitals. Furthermore, similar to some species in the group, the surstylus also has longer apical tubercle-like setae. To differentiate this new species from others in the species group, examination of the male genitalia is required for diagnosis: the surstylus is small and triangular with several dense rows of tubercle-like setae along the inner-distal margin with the apical setae slightly longer and posteriorly-directed ( Fig. 235 ); the base of the mesophallus ends past the base of the distiphallus; the distiphallus is thick and stout, and in profile the basal section is as high as long and as long as the pointed distal section; in ventral view, the sides of the distiphallus are subparallel with the middle bulging ( Figs. 238, 239 ).

Two stem-boring Melanagromyza species have previously been reared from Helianthus annuus : M. cunctanoides Blanchard , known only from Argentina, and M. splendida Frick , which occurs in both North and South America ( Spencer 1990; Shi & Gaimari 2015). Spencer (1981) listed a female of M. viridis (Frost) reared from “ Helianthus stems” in California, but all other data indicate that this species feeds in seed heads, including specimens reared from H. debilis Nutt. in Florida ( Spencer & Stegmaier 1973). A fourth species, M. minimoides Spencer , has been reared from seed heads of H. annuus in California ( Shi & Gaimari 2015).

Figures

FIGURES 234–239. Melanagromyza palmeri spec. nov., male genitalia; 234: hypandrium, metepiphallus, ventral; 235: external components, ventral; 236: same, left lateral; 237: ejaculatory apodeme; 238: phallus, ventral; 239: phallus, left lateral.