Anthomyza neglecta, Collin, 1944

Roháćek, Jindřich & Barber, Kevin N., 2016, Nearctic Anthomyzidae: a monograph of Anthomyza and allied genera (Diptera), Acta Entomologica Musei Nationalis Pragae (suppl.) 56, pp. 1-412 : 229-231

The Anthomyza neglecta group

The Anthomyza neglecta group was established by ROHÁĆEK (2006a, 2009a) for three Palaearctic species, viz. A. neglecta Collin, 1944 , A. paraneglecta Elberg, 1968 and A. orineglecta Roháček, 2006 . In the Nearctic Region, four additional species belonging to this group have been found, including Anthomyza variegata ( Loew, 1863) and three new species described below, viz. A. dichroa sp. nov., A. gibbiger sp. nov. and A. orthogibbus sp. nov. However, although all the above-named species are distinctly related, the inclusion of the Nearctic species required redennition of the taxonomic limits of the A. neglecta group, because not all added species share all characters used by ROHÁĆEK (2006a: 129) to diagnose the group. The expanded A. neglecta group can be best diagnosed by the following (most of them obviously apomorphic) characters: (1) white pilosity of the 1st antennal nagellomere long; (2) pregonite simplined and with a very reduced posterior process; (3) postgonite usually with 1 lateral seta; (4) saccus of distiphallus shortened; (5) nlum robust, not attenuated apically but ending in a curved digitiform terminal process; (6) female T7+S7 forming a compact conical sclerite with anterolateroventral (often pouch-like) lobes; (7) annular sclerite in female genital chamber small and asymmetrically bent; (8) spermathecae with shallow terminal impression.

The A. neglecta group was also connrmed as monophyletic (although with only European species included) by analyses of molecular data (ROHÁĆEK et al. 2009; ROHÁĆEK & TÓTHOVÁ 2014). Its relationship to other groups of Anthomyza has not been recognized with certainty. Two separate analyses of morphological ( ROHÁĆEK 2009a: Fig. 141 ) and molecular data (ROHÁĆEK et al. 2009: Fig. 2 ) placed it as a sister group to an E. Palaearctic clade including A. ssavosterna Sueyoshi & Roháček, 2003 and the sister pair A. bellatrix Roháček, 1984 + A. trifurca Sueyoshi & Roháček, 2003 , while the molecular analysis of ROHÁĆEK & TÓTHOVÁ (2014: Fig. 1 ) postulated it to have a common ancestor with the A. collini group.

Inasmuch as three of the Nearctic species ( A. variegata , A. gibbiger , A. orthogibbus ) have relatively simple, nat and not or weakly medially bent gonostyli (plesiomorphic, those of A. variegata of the most ancestral type), it is possible that all Palaearctic species ( A. neglecta , A. paraneglecta , A. orineglecta ) which have strongly curved gonostyli could be derived later and probably from the ancestor of the A. variegata + A. dichroa sister pair (probable synapomorphies: very long ciliation of 1st nagellomere; 1 pair of internal sclerites in female genital chamber). They (together with A. variegata and A. dichroa ) also lack the distinctive synapomorphies of the other Nearctic sister pair ( A. gibbiger + A. orthogibbus ), see below.

Another hypothesis (preferred here) presupposes that all four Nearctic species are derived from a common ancestor (possible synapomorphies: aedeagal part of folding apparatus with armature reduced to small tubercles; female T7+S7 dorsomedially shortened and weakened to interrupted; internal sclerites of female genital chamber weakly sclerotized) so forming the sister group to a branch with Palaearctic species ( A. neglecta , A. paraneglecta , A. orineglecta ). The latter three species can be clustered on the basis of the following synapomorphies: caudal process of transandrium with spinulae reduced and female genital chamber with annular sclerite situated ventrally under the paired internal sclerites.

Key to identincation of the Nearctic species of the Anthomyza neglecta group

1 Antenna with strikingly long ciliation of 1st nagellomere ( Fig. 395 ). Head about as long as high and eyes more broadly ovoid ( Figs 381 , 404 ). Wing broader ( Figs 437, 438 ). Caudal process of transandrium (simple dorsally) and basal membrane densely prickly spinulose ( Figs 387, 388 ). Female T7+S7 dorsally posteromedially membranous, with posterior dark stripe interrupted in the middle ( Figs 394 , 413 ). ............... 2

– Antenna with somewhat shorter ciliation of 1st nagellomere. Head distinctly longer than high and eyes more elongately ovoid ( Figs 383 , 420 ). Wing narrower ( Figs 439, 440 ). Caudal process of transandrium with peculiar dorsal hump-like projection and basal membrane shortly spinulose ( Figs 423, 425, 426 ). Female T7+S7 dorsally complete, with posterior dark stripe continuous ( Figs 431 , 450 ). .............................. 3

2(1) Arista long ciliate ( Fig. 395 ). Scutellum often with 1–3 small erect setulae between apical sc ( Fig. 398 ). Gonostylus ( Figs 391 , 400 ) nat, of elongately oval outline, micropubescent on most of its outer side. Medandrium dorsally narrowed and with distinct corners ( Fig. 385 ). Female T7+S7 larger, dorsally very shortened and dorsomedially membranous (interrupted, Fig. 394 ), ventrally without anterior ledge-like stripe ( Fig. 393 ), and with large pouch-like anteroventrolateral lobes and brown posterior dorsolateral band larger ( Fig. 392 ). ............................................ A. variegata ( Loew, 1863)

– Arista with cilia shorter. Scutellum always without additional setulae between apical sc. Gonostylus slender and strongly curved medially ( Fig. 406 ), with micropubescence on outer side reduced ( Fig. 412 ). Medandrium dorsally broad and with corners rounded ( Fig. 406 ). Female T7+S7 smaller, dorsomedially only posteriorly membranous (interrupted, Fig. 413 ), with pouch-like anteroventrolateral lobes smaller but ventrally with distinct anterior transverse ledge-like stripe ( Fig. 415 ) and brown posterior dorsolateral band smaller ( Fig. 413 ). ...................................................... A. dichroa sp. nov.

3(2) Male with ctenidial spine on f 1 long, markedly longer than maximum width of t 1. Gonostylus short and broad, posteroproximally dilated and with apex truncate ( Fig. 429 ). Female 1st nagellomere entirely yellow or with outer side brownish-darkened. Female T7+S7, in lateral view, shorter, projecting anteroventrally and with more or less distinct ventral dome-like bulge ( Fig. 431a , arrows); T6 sometimes without posterior dark stripe or with only faint darkening ( Fig. 431 ); posterior stripes tending to become less distinct on more anterior tergites; T7+S7 usually with posterior dark stripe shorter and T8 short ( Fig. 431 ). ............................................................................ A. gibbiger sp. nov.

– Male with ctenidial spine small, as long as or shorter than maximum width of t 1. Gonostylus elongate, narrow, gradually tapered towards bidentate apex ( Fig. 448 ). Female 1st nagellomere always with outer side brownish-darkened. Female T7+S7, in lateral view, longer, projecting more angularly anteromedially and not bulging ventrally ( Fig. 450a , arrows); T6 always with posterior dark stripe distinct ( Fig. 450 ); posterior stripes often remaining strong on all tergites; T7+S7 usually with posterior dark stripe longer and T8 long ( Fig. 450 ). ........................................................... A. orthogibbus sp. nov.

Figures

Figs 139–145. Arganthomyza bivittata Roháček & Barber, 2013, paratype female (Canada: Ontario). 139 – female genital chamber and apex of postabdomen, laterally; 140 – spermatheca; 141, 142 – ventral receptacle, whole laterally (141) and apex ventrally (142); 143 – spermatheca; 144 – internal sclerites, laterally; 145 – the same, ventrally. Scales = 0.1 mm (Fig. 139) and 0.05 mm (others). For abbreviations see p. 11. Adapted from ROHÁĆEK & BARBER (2013: Figs 93–99).

Figs 2–3. Nearctic species of the genus Anthomyza. 2 – A. shewelli sp. nov., a pair (male on left) on leaf of Carex sp. (Canada:Ontario:Dubreuilville, Magpie River), body length ca.2.4 mm (male) and 3.1 mm (female); 3 –A.mcalpinei sp. nov., living male, laterally (Canada:Ontario:Sault Ste. Marie, Finn Hill), body length ca.2.8 mm. Photo by J. Roháček.

Fig. 1. Anthomyza dichroa sp. nov., male, general habitus (Canada: Ontario: Sault Ste. Marie, Bristol Place Park), body length ca. 2.5 mm. Based on photograph by J. Roháček.

Figs 392–395. Anthomyza variegata (Loew, 1863), female (Canada: Ontario).392 – postabdomen, laterally; 393 – the same, ventrally; 394 – the same, dorsally; 395 – antenna, dark form, laterally. Scales = 0.2 mm.

Figs 381–384. Primary types of the Nearctic species of the Anthomyza neglecta group. 381 – A. variegata (Loew, 1863), lectotype male, laterally and type labels, body length 2.50 mm; 382 – A. dichroa sp. nov., holotype male, laterally, body length 2.74 mm; 383 – A. gibbiger sp. nov., holotype male, laterally, body length 2.78 mm; 384 – A. orthogibbus sp. nov., holotype male, laterally, body length 2.62 mm. Photo by J. Roháček.

Figs 401–405.Living Anthomyza dichroa sp. nov. and its habitat.401 – A. dichroa sp. nov., male, dark form, dorsally, body length ca. 2.5 mm; 402 – same specimen, laterally (Canada: Ontario: Sault Ste. Marie, Bristol Place Park); 403 – marshy area bordering a small lake S of Rocky Island lake (Canada: Ontario), habitat of A. dichroa; 404 – A. dichroa sp. nov., male head of pale form sublaterally; 405 – the same, dark form (both from Canada: Ontario). Photo by J. Roháček (Figs 401–403) and M. Deml (Figs 404, 405).

Figs 437–440. Wings of the Nearctic species of the Anthomyza neglecta group. 437 – A. variegata (Loew, 1863) male, wing length 2.4 mm (USA:Tennessee); 438 – A.dichroa sp.nov., male, wing length 2.5 mm (Canada:Ontario); 439 – A. gibbiger sp. nov., male, wing length 2.3 mm (Canada: Ontario); 440 – A. orthogibbus sp. nov., male, wing length 2.5 mm (Canada: Ontario). Photo by K. N. Barber.

Figs 385–391. Anthomyza variegata (Loew, 1863), male (Canada: Ontario). 385 – external genitalia, caudally; 386 – the same, laterally; 387 – hypandrial complex, laterally; 388 – transandrium, caudally; 389 – apex of nlum, subventrally; 390 – aedeagal complex, laterally; 391 – gonostylus, laterocaudally (widest extension). Scales = 0.05 mm (Fig. 389) and 0.1 mm (others).

Figs 413–418. Anthomyza dichroa sp. nov., paratype female (Canada: Ontario). 413 – postabdomen, dorsally; 414 – ventral receptacle,lateroventrally; 415 – postabdomen, ventrally; 416 – spermathecae; 417 – female internal sclerites, ventrally; 418 – female genital chamber and apex of postabdomen, laterally (8th segment with micropubescence omitted). Scales = 0.2 mm (Figs 413, 415), 0.05 mm (Fig. 416) and 0.1 mm (others).

Figs 419–421. Living Anthomyza gibbiger sp. nov. and its habitat. 419 – A. gibbiger sp. nov., male, pale form, dorsally, body length ca. 2.6 mm; 420 – same specimen, laterally (Canada: Ontario: Sault Ste. Marie, Finn Hill); 421 – wet meadow at Sault Ste. Marie (Finn Hill), habitat of three species of the A. neglecta group, viz. A. gibbiger, A. orthogibbus and A. dichroa. Photo by J. Roháček.

Figs 422–429.Anthomyza gibbiger sp. nov., paratype male (Canada: Ontario).422 – external genitalia, caudally; 423 – transandrium, dorsally; 424 – external genitalia, laterally; 425 – hypandrial complex, laterally; 426 – transandrium, caudally; 427 – aedeagal complex, laterally; 428 – apex of nlum, subventrally; 429 – gonostylus, laterocaudally (widest extension). Scales = 0.05 mm (Fig. 428) and 0.1 mm (others).

Figs 430–436. Anthomyza gibbiger sp. nov., paratype female (Canada: Ontario). 430 – spermatheca; 431 – postabdomen, dorsally; 431a – lateral outline of T7+S7; 432 – postabdomen, ventrally; 433 – female internal sclerites, laterally; 434 – the same, ventrally; 435 – spermatheca; 436 – distal part of female genital chamber, laterally. Scales = 0.2 mm (Figs 431, 431a, 432), 0.05 mm (Figs 430, 435) and 0.1 mm (others).

Figs 449–455. Anthomyza orthogibbus sp. nov., paratype female (Canada: Ontario). 449 – spermatheca; 450 – postabdomen, dorsally; 450a – lateral outline of T7+S7; 451 – postabdomen, ventrally; 452 – female internal sclerites, laterally; 453 – the same, ventrally; 454 – spermatheca; 455 – distal part of female genital chamber, laterally. Scales = 0.05 mm (Figs 449, 454), 0.2 mm (Figs 450, 450a, 451) and 0.1 mm (others).

Figs 396–400.Anthomyza variegata (Loew, 1863), female (Canada: Ontario) and male (USA: District of Columbia). 396 – female genital chamber and apex of female postabdomen, laterally; 397 – female genital chamber, ventrally; 398 – female scutellum, dorsally; 399 – spermathecae; 400 – male gonostylus, laterocaudally (widest exension, micropubescence omitted).Scales = 0.1 mm (Figs 396–398) and 0.05 mm (Figs 399, 400).For abbreviations see p. 11.

Figs 406–412. Anthomyza dichroa sp. nov., paratype male (Canada: Ontario). 406 – external genitalia, caudally; 407 – the same, laterally; 408 – hypandrial complex, laterally; 409 – transandrium, caudally; 410 – apex of nlum, subventrally; 411 – aedeagal complex, laterally; 412 – gonostylus, laterocaudally (widest extension). Scales = 0.05 mm (Fig. 410) and 0.1 mm (others).

Figs 441–448. Anthomyza orthogibbus sp. nov., paratype male (Canada: Ontario). 441 – external genitalia, caudally; 442 – transandrium, dorsally; 443 – external genitalia, laterally; 444 – hypandrial complex, laterally; 445 – transandrium, caudally; 446 – aedeagal complex, laterally; 447 – apex of nlum, subventrally; 448 – gonostylus, lateroventrocaudally, widest extension. Scales = 0.05 mm (Fig. 447) and 0.1 mm (others).