Melanagromyza rutella, 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 rutella sp. nov.

Figs 293-296

Description.

Wing length 2.5-2.7 mm (♂), 2.4-2.8 mm (♀). Length of ultimate section of vein M4 divided by penultimate section: 0.6-0.7. Eye height divided by gena height: 2.1-5.9. Clypeus broadly rounded. Ocellar triangle and fronto-orbital plate subshiny. First flagellomere narrow, not broadly rounded below. Fronto-orbital plate and parafacial projecting with portion visible laterally 1/2 height of first flagellomere; fronto-orbital plate well-developed, setae inset. Ocellar triangle subshiny to matt, sometimes appearing to end at posterior ori, but if anterior margin ill-defined, then appearing to continue to lunule. Gena rounded, highest behind midpoint of eye.

Chaetotaxy: Three ori (four on one side of IN male); two ors. Orbital setulae short, in up to four irregular rows, erect to reclinate. Eye pilose dorsomedially. Two dorsocentral setae. Acrostichal setulae in eight to ten irregular rows. Mid tibia with one or (more commonly) two posteromedial setae.

Colouration: Body, including halter, dark brown in base colour. Notum greenish (faded anteriorly); femora sometimes also slightly reflective. Calypter margin and hairs white. Abdomen with greenish shine, sometimes becoming slightly coppery/reddish.

Genitalia: (Figs 293-296 ) Posterodorsal margin of epandrium slightly produced; posteroventral spine well-developed. Surstylus 1/2 height of epandrium, with up to three rows of tubercle-like setae along inner distal margin. Basiphallus short, U-shaped, and extending slightly past base of distiphallus. Base of mesophallus extending past that of distiphallus; distiphallus with paired ventrolateral tubules shallowly raised from base of distiphallus, or prominent, separate and strongly looped (as illustrated); with dorsoapical margin strongly flared laterally; venter with strong divided carina. Ejaculatory apodeme well-developed with base dark, becoming paler distally on stem; blade large, spade/diamond-shaped, weakly sclerotised but with defined medial rib and strong marginal band (less so laterally) well-defined.

Host.

Unknown.

Distribution.

USA: IN, VA.

Etymology.

L. rutrum for spade, shovel, referring to the shape of the large ejaculatory apodeme.

Type material.

Holotype: USA. VA: Fairfax Co., Great Falls Park, quarry, 38°59.1'N, 77°14.8'W, Malaise trap, D.R. Smith, 24.iv-2.v.2007 (1♂, USNM).

Paratypes: USA. IN: La Fayette, 11.v.1916, J.M. Aldrich (1♂ 2♀, USNM), VA: Same collection as holotype (1♂ 2♀, USNM; 2♀, CNC), 3-10.v.2007 (3♀, USNM).

Comments.

Melanagromyza rutella is dark (i.e., without a slightly paler gena, shoulders, etc.) with a white calypter and three ori on both sides of the frons. The gena is also often relatively high, the blade of the ejaculatory apodeme is nearly diamond-shaped, the distiphallus is stout and strongly flared apically, the ventrolateral tubules of the phallus are distinct and sometimes broadly looped, and the distiphallus has a single internal rectangular pad with numerous transverse rows of small spines.

There is a resemblance to Melanagromyza urticae Eiseman and Lonsdale ( Eiseman et al. 2021: figs 16-19, 111-116), especially with regards to the male genitalia, but this other Iowa species has two ori, three ors, the surstylus is not produced slightly posteriorly, the mesophallus is inserted almost basally on the distiphallus (the ventrolateral tubules are more pronounced in M. rutella ), the dorsal chamber of the distiphallus is stouter and almost parallel-sided in ventral view (not constricted medially) and higher in lateral view, and the tubule emerging from the dorsal chamber apically is longer.

Figures

Figures 293 - 296. Melanagromyza rutella Lonsdale, sp. nov. 293 phallus, ventral 294 phallus, left lateral 295 ejaculatory apodeme 296 external components, left lateral.