Penthetria (Loew, 1868)

Fitzgerald, Scott J., 2021, Penthetria Meigen (Diptera: Bibionidae): Revision of the New World species and world catalog, Zootaxa 4926 (4), pp. 451-500 : 460-461

publication ID	https://doi.org/ 10.11646/zootaxa.4926.4.1
publication LSID	lsid:zoobank.org:pub:3ADD4A2B-A3F9-4379-A8FE-39DD867531F7
DOI	https://doi.org/10.5281/zenodo.4546074
persistent identifier	https://treatment.plazi.org/id/A157FD05-FFB4-4B4F-FF2F-FA52FA0520D3
treatment provided by	Plazi
scientific name	Penthetria
status

Treatment

Key to the species of New World Penthetria View in CoL View at ENA

Based on males (eyes holoptic). Females (eyes dichoptic) of some of these species are presently unknown ( P. dolichopeza ) or indistinguishable. To improve the efficiency of the identification process of specimens from USA and Canada proceed directly to couplet six (though females from USA / Canada are presently indistinguishable, they may be separated with relative confidence based on geographic distribution in areas where species appear to be allopatric (see distribution of species in Maps 2 View MAP 2 & 3 View MAP 3 )).

1 Ventromedian lobes of posterior margin of gonocoxites strongly developed ( Fig. 34 View FIGURES 33–35 , 45 View FIGURES 42–45 , vml) with ventromedian cleft often slightly deeper or more narrow in appearance due to stronger flanking lobes ( Fig. 34 View FIGURES 33–35 inset); gonostylus relatively slender in posterior view ( Fig. 35 View FIGURES 33–35 ) and apically acute; posterior margin of tergite nine with relatively shallow cleft, usually about one-third depth of tergite; tergite nine never deeply emarginate (over one-half length of tergite), shelf-like posteriorly ( Fig. 10 View FIGURES 9–11 ), or with a field of densely-set, short, black, spine-like setae on posteroventral edge of tergite ( Fig. 5 View FIGURES 4–6 , sls); female with tergite nine well developed and strongly lobate posterolaterally ( Fig. 54 View FIGURES 54–57 ), cerci with second (ultimate) segment relatively short, and posteromedian lobes of sternite eight relatively broad ( Fig. 55 View FIGURES 54–57 ); South America..................... P. neonigrita Fitzgerald View in CoL n. sp.

- Ventromedian lobes of posterior margin of gonocoxites weakly ( Fig. 11 View FIGURES 9–11 , vml) to moderately ( Figs. 20 View FIGURES 16–20 & 25 View FIGURES 24–29 , vml) developed, sometimes entirely absent ( Fig. 15 View FIGURES 14–15 ); posteromedian cleft usually shallower and broader ( Fig. 20 View FIGURES 16–20 , vmc) or entirely absent; gonostylus variable, but not slender in posterior view unless tergite nine deeply emarginate or gonostylus apically notched; tergite nine variable; female terminalia not with the above combination of characters; Canada to Central America.............. 2

2 Gonostylus glossy, shining, with long hairs basally, but only minute sparse hairs beyond base ( Figs. 4–6 View FIGURES 4–6 , 9–11 View FIGURES 9–11 ); tergite nine with posteromedian emargination deep, extending at least half, but usually more, the length of the tergite ( Figs. 4–5 View FIGURES 4–6 , 9 View FIGURES 9–11 ) and posteroventral edge bearing a field of densely-set, short, black, spine-like setae sharply contrasting typical setae on remainder of tergite ( Fig. 5 View FIGURES 4–6 , sls; can be difficult to see in undissected specimens); tergite nine sometimes shelf-like posteroventrally ( Fig. 10 View FIGURES 9–11 ); apex of gonostylus broadly rounded ( Figs. 9–11 View FIGURES 9–11 ) or coming to a narrow rounded point ( Fig. 5 View FIGURES 4–6 ), never apically truncate or notched ( Figs 16–20 View FIGURES 16–20 ); females with second (ultimate) segment of cerci elongate and posteromedian lobes of sternite eight relatively narrow ( Figs. 46–48 View FIGURES 46–49 ); in both sexes vein R 2+3 sometimes with a basal appendix ( Fig. 2 View FIGURES 2–3 , ba); Mexico and Central America............................................................................................ 3

- Gonostylus with long hairs basally as well as beyond base (e.g., Figs. 7–8 View FIGURES 7–8 ); tergite nine without posteromedian emargination or with emargination more shallow and most often extending one-fifth to one-third the length of the tergite, but sometimes slightly over one-half the length of the tergite; vein R 2+3 without a basal appendix (e.g., Figs. 21 View FIGURES 21–22 , 23 View FIGURE 23 ); tergite nine never shelf-like or with posteroventral edge with a field of densely-set, short, black, spine-like setae sharply contrasting typical setae on remainder of tergite; gonostylus variable; females with second (ultimate) segment of cerci shorter and posteromedian lobes of sternite eight broader ( Figs. 49–53 View FIGURES 46–49 View FIGURES 50–53 , 56 View FIGURES 54–57 ) (females of these species indistinguishable except some by geographic range); widespread...... 4

3 Ninth tergum almost completely divided into two plates by posterior emargination ( Fig. 9 View FIGURES 9–11 ); posterior, inner (ventral) surface of ninth tergite developed into a pair of broad flat shelves when viewed posteriorly ( Fig. 10 View FIGURES 9–11 ); gonostylus broad and broadly rounded apically ( Figs. 9–11 View FIGURES 9–11 ); R 2+3 usually without, but sometimes with a basal appendix; female with sternite ten truncate/broadly rounded posteriorly? (as in Fig. 49 View FIGURES 46–49 ; sternite 10 not visible in Fig. 48 View FIGURES 46–49 as it is partly telescoped within preceding segments) (but see notes on this character in “Remarks” under P. appendicula View in CoL ).................................. P. distincta Hardy View in CoL

- Ninth tergum not so deeply cleft ( Fig. 4 View FIGURES 4–6 ); posterior, inner (ventral) surface of ninth tergite not developed (or at most only very weakly developed) into a pair of broad flat shelves when viewed posteriorly ( Fig. 5 View FIGURES 4–6 ); gonostylus not as broad ( Fig. 5 View FIGURES 4–6 ); R 2+3 usually, but not always, with a basal appendix ( Fig. 2 View FIGURES 2–3 ); female ( Fig. 3 View FIGURES 2–3 ) with sternite ten tapered posteriorly to a rounded point? ( Fig. 47 View FIGURES 46–49 ) (but see notes on this character in “Remarks”)..................................... P. appendicula Hardy View in CoL

4 Hind basitarsus, parallel-sided, very slender elongate (hind tibia only about 2.5 times as long as basitarsus; Fig. 12 View FIGURES 12–13 , hb); gonostylus short and stout with a distinct anteroapical thorn ( Figs. 14–15 View FIGURES 14–15 ); gonocoxite dorsally with an apical, medially-directed lobe just anterior to the gonostylar socket ( Fig. 14 View FIGURES 14–15 , dal); ventromedian lobes of gonocoxites absent ( Fig. 15 View FIGURES 14–15 ); southern Mexico, Costa Rica................................................................. P. dolichopeza Fitzgerald View in CoL n. sp.

- Hind basitarsus usually robust to slightly swollen and sausage-shaped, sometimes more slender, but never slender and greatly elongated ( Figs. 23 View FIGURE 23 , 30–31 View FIGURES 30–32 , hb); gonostylus not as above; gonocoxite dorsally without an apical medially-directed lobe just anterior to the gonostylar socket; ventromedian lobes of gonocoxites variable; widespread........................... 5

5 In dorsal and ventral views, divergent horn-like lobes of paramere more strongly projecting caudally and ventrally, often appearing apical (even though really more subapical in position) ( Figs. 24–26 View FIGURES 24–29 , dlp), sometimes divergent lobes slightly less projecting ( Figs. 28–29 View FIGURES 24–29 ) making them barely visible or barely not visible in a strictly dorsal view, but in the latter case at least apex (most posterior aspect) of paramere slightly laterally compressed into a ridge so that apex appears more narrow (as an apical nubbin) in dorsal view rather than broadly rounded ( Fig. 29 View FIGURES 24–29 ); apex of gonostylus ( Figs. 24–26, 28–29 View FIGURES 24–29 ) usually broadly rounded or broadly rounded and culminating in an obtuse point medially, sometimes apically slightly truncate, but never with an apical notch; tergite nine uncleft or relatively shallowly cleft (up to about one-third its length) ( Fig. 24 View FIGURES 24–29 ); Mexico and Central America............................................................................ P. mexicana (Hardy) View in CoL

- Divergent horn-like lobes of paramere not visible in dorsal view. In ventral view, divergent horn-like lobes less developed, not strongly projecting or appearing apical, but more collar-like and more confluent with posteroventral edge of paramere ( Figs. 8 View FIGURES 7–8 & 20 View FIGURES 16–20 , dlp); apex (most posterior aspect) of paramere rounded, dome-like in dorsal view, not laterally compressed into a narrow ridge/nubbin, and often with a minute notch ( Figs. 7 View FIGURES 7–8 & as in 16 & 20, p); gonostylus variable; Canada to Central America.. 6

6 Apex of gonostylus minutely truncate or with a small notch (the anterodorsal side of the notch often developed into a small point) ( Figs. 16–20 View FIGURES 16–20 , 36–39); Canada, northwestern USA and USA east of the Rocky Mountains....................... 7

- Gonostylus apically broadly rounded or broadly rounded and culminating in an obtuse median point ( Figs. 7–8 View FIGURES 7–8 ) or, in some Mexican and Central American specimens gonostylus very slightly truncate apically (as in Fig. 19 View FIGURES 16–20 ); Southern Arizona, USA south to Central America....................................................... P. arizonensis Fitzgerald View in CoL n. sp.

7 In posterior view, gonostylus more robust ( Fig. 40 View FIGURES 38–41 ); in dorsal view, paramere more broadly rounded, less diamond-shaped ( Fig. 38 View FIGURES 38–41 , p); USA & Canada east of the Rocky Mountains.......................................... P. heteroptera (Say) View in CoL

- In posterior view, gonostylus more slender ( Fig. 41 View FIGURES 38–41 ); in dorsal view, paramere more diamond-shaped ( Fig. 39 View FIGURES 38–41 , p); northwestern USA, widespread in Canada........................................................ P. yakima Fitzgerald View in CoL n. sp.