Key to the species of Stenotarsus from México, Guatemala and Belize

[Note: Stenotarsus orbicularis Gerstaecker is not included in the key since neither the type nor any other unambiguously identified specimens were available for study]

1. Elytra with foveolate punctures arranged in longitudinal striae, lacking in apical third (Figs. 123, 125); pronotum with longitudinal sulci rather deeply and widely excavated, long, reaching almost middle of pronotum (Figs. 109, 113); mesoventrite with carinae defining three subtriangular areas (Fig. 138); median lobe curved and twisted (Figs. 234–235, 240–241).......... 2

– Elytra with foveolate punctures sparse, not forming longitudinal striae (Figs. 115–122, 124); pronotum with longitudinal sulci moderately impressed, narrow, short, hardly reaching middle of pronotum, sometimes greatly reduced or almost absent (Figs. 90–108, 110–112, 114); mesoventrite without carinae (Fig. 137); median lobe curved in ventral view, linear or weakly sinuate in lateral view (Figs. 200–233, 236–239, 242–243)........................................................... 3

2. Foveolate punctures of elytra small, diameter 2X the diameter of setiferous punctures (Fig. 123); antennae black, with scape light brown; pronotum (Fig. 109) with lateral margins moderately wide (width slightly less than 1/4 of the distance between midpoint of basal pore and hind angle), front angles moderately produced; longitudinal sulci moderately wide............................................................................................ Stenotarsus rulfoi sp. nov.

– Foveolate punctures of elytra large, diameter 4X the diameter of setiferous punctures (Fig. 125); antennae black, with first three or four antennomeres light brown; pronotum (Fig. 113) with lateral margins wide (width slightly less than 1/3 of the distance between midpoint of basal pore and hind angle), front angles markedly produced; longitudinal sulci distinctly wide....................................................................................... S. spiropenis sp. nov.

3. Basal pores of pronotum large, oblique (Figs. 79, 98); metaventrite with one large setose pore posterior to each mesocoxa, its width almost half width of mesocoxa (Fig. 141)............................................ S. marginalis Arrow

– Basal pores of pronotum small to moderately large, variable in shape (Figs. 80–83, 91–97, 100–105, 107–108, 110–112, 114); metaventrite with pair of small setose pores posterior to each mesocoxa, width of each one approximately a third of width of mesocoxa (Fig. 142).................................................................................... 4

4. Antennomeres 2–8 moniliform, as long as wide; club slightly longer than rest of antenna, its articles elongate, almost parallel sided (Figs. 54, 63; 71)................................................................................. 5

– Antennomeres 2–8 elongate, distinctly longer than wide (Figs. 55–62, 64–70; 72–78); club shorter than rest of antenna, its articles widened apically.................................................................................. 7

5. Pronotum (Fig. 90) with lateral margins lacking tooth at midlength, with longitudinal sulci comparatively long and deeply marked; median lobe distinctly broadened apically in ventral view (Fig. 201)........................ S. cortesi sp. nov.

– Pronotum (Figs. 99, 106) with lateral margins bearing small tooth at midlength, with longitudinal sulci comparatively short and feeble; median lobe weakly widened apically in ventral view (Figs. 219, 233).................................. 6

6. Pronotum and elytra red, each with a large, central, black macula (Fig. 24); median lobe strongly widened apically, in lateral view (Fig. 218)................................................................ S. mesoamericanus sp. nov.

– Pronotum and elytra entirely reddish brown (Fig. 34); median lobe weakly widened apically, in lateral view (Fig. 232)..................................................................................... S. parallelicornis sp. nov.

7. Metatrochanter and metafemur with unusually long and sparse setae, their length 0.3–0.5X length of the metafemur (Fig. 144); metatibia stout and slightly sinuate, more conspicuously in males (Figs. 144, 159, 184); body size 3.4–3.9 mm, completely dark brown except black antennal club (Fig. 15)............................................. S. exiguus Gorham

– Metatrochanter and metafemur densely covered with normal, comparatively short, decumbent setae, their length much smaller than 0.3X length of metafemur; metatibia linear or rarely slightly curved, bent medially and rather narrow (e.g. Figs. 145–149); body size and color variable............................................................................. 8

8. Scutellum semicircular (Fig. 135); elytral epipleuron distinctly wide at base, 1.2X wider than anterior border of intercoxal process of metaventrite; male metatrochanter with a small sharp spine (Figs. 148, 174); median lobe with an accessory process (Figs. 231).............................................................................. S. ovali s Arrow

– Scutellum triangular (Figs. 134); elytral epipleuron narrow to moderately wide at base, as wide or narrower than anterior bor- der of intercoxal process of metaventrite; metatrochanters unarmed in both sexes; median lobe without accessory process... 9

9. Lateral margins of pronotum scarcely raised, very narrow, about as wide as a sixth of distance between basal pore and hind angle, (Fig. 96); meso- and metatibiae wide, flattened, strongly curved in males (Figs. 146, 166, 170); body brown with antennae black except scape, or scape and pedicel wich are brown, legs uniformly brown or femur brown and tibiae and tarsi black (Figs. 21, 28)........................................................................................ 10

– Lateral margins of pronotum raised, comparatively wide, as wide or wider than a fifth of distance between basal pore and hind angle (Figs. 92–95, 97, 100–104, 107–108, 110–112); mesotibia always linear, metatibia most often linear (Figs. 161–163, 168–169, 171–173, 178, 181–183), if weakly bent or curved in males of some species then distinctly narrow (Figs. 160, 165); body coloration variable; if body completely brown, then antennae have at least first four articles brown and others are black.................................................................................................... 11

10. Tibiae and tarsi reddish brown (Fig. 21); metatibia broad, markedly curved (Fig. 146), with medial row of tubercles in male

(Fig. 164); median lobe widened at basal third in ventral view (Figs. 213)............................ S. latipes Arrow – Tibiae and tarsi dark fuscous or black (Fig. 28); metatibia moderately wide and curved, without tubercles on medial face (Fig. 170); median lobe (Figs. 223) narrow at basal third in ventral view.............................. S. molgorae sp. nov.

11. Pronotum with basal pores moderately large, reniform, markedly oblique; basal sulcus present, complete or occasionally lacking medially (Figs. 92–95, 100–101, 105, 107–108, 111, 114).................................................. 12

– Pronotum with basal pores comparatively small, rounded or elongate, rarely oblique; basal sulcus indistinct or absent (Figs. 93–94, 97, 102, 104, 110, 112).......................................................................... 20

12. Antennomeres 4–7 thin, about 2X as long as wide; antennomere 9 2.2X wider than 8 (Fig. 59); pronotum with lateral margins comparatively narrow (Fig. 95); elytra with setae relatively short and decumbent; head black............ S. kafkai sp. nov.

– Antennomeres 4–7 comparatively stout, 1.7X as long as wide or shorter; antennomere 9 about 1.8X wider than 8 (56, 64–65, 68, 72, 75, 78); pronotum with lateral margins comparatively wide (Figs. 92, 100–101, 103, 107–108, 111, 114); elytra with setae comparatively long and suberect; head red or brown..................................................... 13

13. Ventrite V of females markedly emarginate medially (Fig. 189); pronotum with basal sulcus complete (Fig. 101); antenna with terminal antennomere short, subovate (Fig. 65), 1.4X as long as wide, 3.5X as long as pedicel; median lobe constricted apically, in lateral view (Fig. 220)....................................................... S. militaris Gerstaecker

– Ventrite V of females truncate (Figs. 187, 191); pronotum with basal sulcus complete, or vanishing medially (Figs. 92, 100, 103, 107–108, 111, 114); antenna with terminal antennomere elongate, oval or subrectangular (Figs. 56, 64, 68, 72, 75, 78), about or longer than 1.4X as long as wide and 3.5X as long as pedicel; median lobe not distinctly constricted apically, in lateral view............................................................................................... 14

14. Legs long and slender, (Figs. 145, 160; 176–177) slightly less pronounced in females (Fig. 185); male metafemur with a tooth basally (Figs. 150–153), metatibia slightly bent medially at apical third, with a row of small tubercles; metaventrite of males with a transverse, densely punctate concavity, at anterior margin between mesocoxae (Figs. 88–89); median lobe gradually widening apically, in lateral view (Fig. 204), gradually narrowing apically, in ventral view, slightly flexed laterally with a small apical crest (Fig. 205)................................................................................. 15

– Legs moderately long and slender, unarmed (Figs. 168, 172, 183); metatibia linear; metaventrite without cavities or other modifications near anterior margin in both sexes; median lobe not as above, wider apically or slightly sinuate, in lateral view (210– 211, 226–227, 242–243)............................................................................... 18

15. Prosternal process narrow at base, scarcely widened apically (Fig. 131); body size 5.1–5.4 mm (Fig. 39); tooth of male metafemur scarcely developed (Fig. 153)........................................................ S. shockleyi sp. nov.

– Prosternal process moderately narrow at base, strongly widened apically (Fig. 127); body size 5.4–7.9 mm; tooth on male metafemur moderately to well developed (Fig. 150–152)..................................................... 16

16. Tooth on male metafemur widely truncate (Fig. 151); foveolate punctures on elytra comparatively large and deep (Fig. 122); body size 6.9–7.9 mm, 1.80–1.83X as long as wide; elytra completely reddish brown (Figs. 35)........ S. raramuri p. nov.

– Tooth on male metafemur with apex narrowly blunt or acute (Fig. 150, 152); foveolate punctures on elytra rather small and shallow (Fig. 117); body size 5.4–7.4 mm, 1.56–1.75X as long as wide; elytron red with large black macula, or completely brown (Figs. 16–17, 36)................................................................................ 17

17. Tooth on male metafemur large, pointed (Fig. 152); body size 5.4–6.6 mm (Fig. 36); antenna red with antennomeres 7–11 black; legs red; pronotum red with large triangular macula not surpassing pores at base; elytron red with large, central, black macula, macula always reaching apical third.......................................... S. rubrocinctus Gerstaecker

– Tooth on male metafemur moderately large, blunt or rounded apically (Fig. 150); body size 6.4–7.4 mm (Fig. 16–17); antenna black or with antennomeres 1–6 red, brown or infuscate; legs black, brown or red; body completely brown or contrastly colored: pronotum uniformly black or with angles red, black part sometimes subtriangular, surpassing basal pores at base; elytron uniformly reddish-brown or red with large, central, black macula, macula sometimes hardly reaching apical third..................................................................................... S. globosus Guérin-Méneville

18. Terminal antennomere elongate, 1.7X as long as wide, 4.4X longer than pedicel (Fig. 64); median lobe distinctly thin (Figs. 210–211).......................................................................... S. mexicanus sp. nov.

– Terminal antennomere moderately elongate, 1.4–1.5X as long as wide, 3.5–3.7X longer than pedicel (Figs. 68, 69); median lobe moderately broad (Figs. 226–227, 242–243)........................................................... 19

19. Pronotum with basal pores small, basal sulcus incomplete, lateral margins wide, width 1/3 of distance between midpoint of basal pore and hind angle (Fig. 114); median lobe rather linear, narrowing apically, in lateral view (Fig. 242); elytron orangered with large, black macula (Fig. 42).................................................... S. thoracicus Gorham

– Pronotum with basal sulcus complete, basal pores moderately large, lateral margins comparatively narrow, width 1/4 of distance between midpoint of basal pore and hind angle (Fig. 103); median lobe sinuate, same width throughout (Fig. 226); elytron uniformly brown (Fig. 30)....................................................... S. nigricans Gorham

20. Tarsomere 2 of all legs narrow, not widened distally, at most 1.3X wider than tarsomere 4 at midlength (Fig. 155)........ 21

– Tarsomere 2 of all legs widened distally, at least 2.0X wider apically than tarsomere 4 at midlength (Figs. 157).......... 23

21. Base of pronotum clearly emarginate near scutellum (Fig. 97); antenna distinctly long, 0.40–0.45X as long as body in females, 0.45–0.50X in males, terminal antennomere elongate (Fig. H8); median lobe strongly widened apically, in lateral view (Fig. 214)............................................................................. S. lemniscatus Gorham

– Base of pronotum rounded or truncate near scutellum (Figs. 94, 103); antenna short, 0.33–0.38X as long as body in both sexes, terminal antennomere short to moderately long oval (Figs. 58, 67); median lobe of same width throughout, in lateral view (Fig. 224) or slightly narrowing apically (Fig. 208).............................................................. 22

22. Base of pronotum rounded (Fig. 94); terminal antennomere parallel sided (Fig. 58); pronotum and elytra contrastly colored (Fig. 19); metaventrite of males with a deep longitudinal pit or incision near anterior margin (Fig. 84); median lobe moderately

broad, in ventral view, somewhat constricted after midlength (Fig. 209)............................. S. incisus sp. nov. – Base of pronotum truncate near scutellum (Fig. 102); terminal antennomere oval (Fig. 67); pronotum and elytra uniformly colored (Fig. 29); metaventrite of males without an excision near anterior margin (Fig. 85); median lobe very narrow throughout its length, in ventral view............................................................ S. monterrosoi sp. nov.

23. Body small (3.0 mm), short oval (Fig. 40), 1.7X longer than wide; elytra ovoid; lateral margins of pronotum wide (Fig. 112); median lobe of same width throughout, in lateral view (Fig. 238)................................. S. smithi Gorham

– Body moderately large (3.60–5.05 mm), long oval (Figs. 18, 31–32, 38); lateral margins of pronotum narrow (Figs. 93, 104, 109); median lobe of different width throughout its length, in lateral view (Figs. 206, 228, 236)....................... 24

24. Terminal antennomere with an angle on lateral margin near midlength (Fig. 69); pronotum and elytra uniformly brown (Fig. 32) or red-orange, each with large, black macula (Fig. 31); median lobe moderately wide, in ventral view (Fig. 229)......................................................................................... S. oblongulus Gorham

– Terminal antennomere without protuberance on lateral margin (Figs. 57, 74); pronotum and elytra always uniformly brown (Figs. 18, 38); median lobe narrow, in ventral view (Figs. 207, 237)............................................. 25

25. Metatibia slightly curved, almost parallel in basal half, then widened at 3/4 (Fig. 149); ventrite I of male abdomen with small, conical protuberance (Fig. 186)........................................................... S. sallaei Gorham

– Metatibia gradually widened apically (Fig. 161); ventrite I of male abdomen without protuberance.... S. guatemalae Arrow