Melanagromyza eoflacensis, Lonsdale, 2021

Lonsdale, Owen, 2021, Manual of North American Agromyzidae (Diptera, Schizophora), with revision of the fauna of the " Delmarva " states, ZooKeys 1051, pp. 1-481 : 1

Melanagromyza eoflacensis sp. nov.

Figs 277-280

Description.

Wing length 2.6-2.7 mm (♂). Length of ultimate section of vein M4 divided by penultimate section: 0.6-0.9. Eye height divided by gena height: 5.3. Clypeus broadly rounded. Ocellar triangle and fronto-orbital plate subshiny to slightly matt with triangle reaching level of mid ori or nearly reaching lunule (tapering anteriorly), and fronto-orbital plate slightly visible laterally. Gena rounded, highest behind midpoint of eye.

Chaetotaxy: Three ori (sometimes four on one side); two ors. Orbital setulae in two irregular rows, erect to reclinate. Eye pilose dorsomedially, hairs relatively dense. Two dorsocentral setae. Acrostichal setulae in eight irregular rows. Mid tibia with one posteromedial seta (shorter than width of tibia).

Colouration: Body, including halter, dark brown in base colour. Gena, parafacial, distal margin of pedicel and inner-distal margin of fronto-orbital plate paler. Notum faintly greenish (faded anteriorly), and femora sometimes also slightly reflective. Calypter margin and hairs white. Abdomen with bluish (MD-Bethseda), greenish (IN, PA) or coppery shine (MD-Plummers Isl.).

Genitalia: (Figs 277-280 ) Epandrium with small posterodistal spine. Metepiphallus with ventral surface dark and with short serrated ridge; lateral margin strongly ridged and nearly separate. Proepiphallus narrow and V-shaped with medial desclerotisation. Hypandrium stout, subtriangular and with small apical process. Basiphallus short and U-shaped; space between basiphallus and distiphallus separated by slightly less than height of basiphallus (slightly more in Lewiston, PA male, illustrated here). Base of mesophallus slightly exceeding that of distiphallus. Distiphallus with spinulose pad along inner-dorsal margin; with thicker basal section ending in bulge before much narrowed apical 1/2; base of distiphallus in IN male straighter and slightly narrower. Ejaculatory apodeme similar to that of M. subvirens , with distal margin darker in holotype.

Etymology.

The specific name indicates similarity to M. osoflacensis Spencer, while indicating is relative eastern distribution (eos - Gr. for east).

Host.

Unknown.

Distribution.

USA: IN, MD, PA, VA.

Type material.

Holotype: USA. MD: Montgomery Co., Bethseda, 3.vi.1972, G. Steyskal (1♂, USNM).

Paratype: USA. IN: LaFayette, 10.v.1915, swept from grass, J.M. Aldrich (1♂, USNM), MD: Plummers Isl., 20.iv.1921, H.S. Barber (1♂, USNM), PA: Lewiston, 7.vi.1940, A.L. Melander (1♂, USNM).

Additional material examined.

USA. VA: Blacksburg , 2100', 1.vi.1962, J.G. Chillcott (1♂ [only wing and genitalia remaining], CNC) .

Comments.

Melanagromyza eoflacensis can be partially diagnosed by a single posteromedial seta on the mid tibia (not two), but similar species ( M. angelicae , M. osoflacensis , M. panacis , M. subvirens, M. brunkei ) may be easily misidentified as this taxon, particularly if one or both of the mid tibiae are damaged. As such, the genitalia should always be examined for verification. The phallus of M. eoflacensis is distinct in having a space between the basiphallus and distiphallus that is nearly equal to the height of the basiphallus, the mesophallus only slightly projects past the base of the distiphallus, and seen laterally, the distiphallus has a thick dorsobasal section ending in a pronounced bulge before it abruptly narrows (similar to the state seen in M. angelicae ).

The terminalia of Melanagromyza angelicae (Figs 257-260 ) differ in having a much longer distance between the basiphallus and the base of the distiphallus. Melanagromyza subvirens (Figs 301-304 ) differs in having a ring-like basiphallus and a flared membranous carina anterodorsally, and the wing is slightly larger. The phalli of M. osoflacensis and M. panacis ( Spencer and Steyskal 1986b: figs 35, 36) are more similar, but the former species has very little space between the basiphallus (with posteromedial notch) and the more gradually tapered distiphallus, the fronto-orbital plate is slightly more pronounced and the ocellar triangle is shinier; the latter species has a slightly longer distance between the basiphallus and the base of the distiphallus and it is stouter-bodied but with a similar wing length (2.5-2.8 mm) and the posterior two ori are more closely spaced. The abdomen in these species is also always shiny green, with that of M. subvirens sometimes also bluish. Also see comments for M. brunkei .

The genitalic illustration of this species was erroneously provided for Melanagromyza osoflacensis Spencer in Shi and Gaimari (2015), provided by the present author, at a period when he was not aware of the identity of this new species.

The Virginia male is only tentatively included as most of the body is missing (only one wing is left on the pin) and the genitalia are preserved on a mini-prep slide on an angle that does not allow for fully confident identification, but it appears to agree with the above description.

Figures

Figures 277 - 280. Melanagromyza eoflacensis sp. nov., male genitalia 277 external components, left lateral 278 hypandrium, ventral 279 hypandrial complex, left lateral 280 phallus and proepiphallus, ventral.

Figures 257 - 260. Melanagromyza angelicae (Frost), male genitalia 257 phallus and proepiphallus, ventral 258 hypandrial complex, left lateral 259 external components, left lateral 260 hypandrium, ventral.

Figures 301 - 304. Melanagromyza subvirens (Malloch), male genitalia 301 hypandrium, ventral 302 external components, left lateral 303 hypandrial complex, left lateral 304 phallus and proepiphallus, ventral.