Stenotarsus

Arriaga-Varela, Emmanuel, Zaragoza-Caballero, Santiago, Tomaszewska, Wioletta & Navarrete-Heredia, Jose Luis, 2013, Preliminary review of the genus Stenotarsus Perty (Coleoptera: Endomychidae) from México, Guatemala and Belize, with descriptions of twelve new species, Zootaxa 3645 (1), pp. 1-79 : 9-11

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

Figures

FIGURES 115 – 125. Surface of elytron of Stenotarsus spp. 115) S. cortesi; 116) S. exiguus; 117) S. globosus; 118) S. kafkai; 119) S. lemniscatus; 120) S. ovalis; 121) S. militaris; 122) S. raramuri; 123) S. rulfoi; 124) S. shockleyi; 125) S. spiropenis.

FIGURES 105 – 114. Pronotum of Stenotarsus spp. 105) S. ovalis; 106) S. parallelicornis; 107) S. raramuri; 108) S. rubrocinctus; 109). S. rulfoi; 110) S. sallaei; 111) S. shockleyi; 112) S. smithi; 113) S. spiropenis; 114) S. thoracicus.

FIGURES 126 – 143. Thoracic structures of Stenotarsus spp. 126 – 133. Prosternal process. 134 – 136. Scutellum. 137 – 138. Mesoventrite. 139 – 140. Metepisternum. 141 – 143. Anterolateral part of metaventrite. 126) S. cortesi; 127) S. globosus, S. rubrocinctus; 128) S. meosamericanus; 129) S. oblongulus; 130) S. ovalis; 131) S. shockleyi; 132) S. spiropenis; 133) S. thoracicus; 134) S. globosus; 135) S. ovalis; 136) S. spiropenis; 137) S. nigricans; 138) S. spiropenis; 139) S. ovalis; 140) S. spiropenis; 141) S. marginalis; 142) S. nigricans; 143) S. spiropenis. PC. Procoxal cavity. PR. Procoxal rest. SP. Setose pore. MC. Mesocoxal cavity.

FIGURES 224 – 243. Lateral and ventral view of median lobe of edeagus of Stenotarsus spp. 224 – 225) S. monterrosoi; 226 – 227) S. nigricans; 228 – 229) S. oblongulus; 230 – 231) S. ovalis; 232 – 233) S. parallelicornis; 234 – 235) S. rulfoi; 236 – 237) S. sallaei; 238 – 239) S. smithi; 240 – 241) S. spiropenis; 242 – 243) S. thoracicus.

FIGURES 90 – 104. Pronotum of Stenotarsus spp. 90) S. cortesi; 91) S. exiguus; 92) S. globosus; 93) S. guatemalae; 94) S. incisus; 95) S. kafkai; 96) S. latipes, S. molgorae; 97) S. lemniscatus; 98) S. marginalis; 99) S. mesoamericanus; 100) S. mexicanus; 101) S. militaris; 102) S. monterrosoi; 103) S. nigricans; 104) S. oblongulus.

FIGURES 200 – 223. Lateral and ventral view of median lobe of edeagus of Stenotarsus spp. 200 – 201) S. cortesi; 202 – 203) S. exiguus; 204 – 205) S. globosus, S. raramuri, S. rubrocinctus, S. shockleyi; 206 – 207) S. guatemalae; 208 – 209) S. incisus; 210 – 211) S. kafkai, S. mexicanus; 212 – 213) S. latipes; 214 – 215) S. lemniscatus; 216 – 217) S. marginalis; 218 – 219) S. mesoamericanus; 220 – 221) S. militaris; 222 – 223) S. molgorae.

FIGURES 79 – 89. 79 – 83. Pronotum of Stenotarsus spp. 84 – 89. Intercoxal process of male metaventrite of Stenotarsus spp. 79) S. marginalis; 80) S. mexicanus; 81) S. oblongulus; 82) S. o valis; 83) S. spiropenis; 84) S. incisus; 85) S. monterrosoi; 86) S. oblongulus; 87) S. ovalis; 88) S. rubrocinctus; 89) S. shockleyi.

FIGURES 54 – 71. Right antennae of Stenotarsus spp. 54) S. cortesi; 55) S. exiguus; 56) S. globosus, S. rubrocinctus; 57) S. guatemalae; 58) S. incisus; 59) S. kafkai; 60) S. latipes; 61) S. lemniscatus; 62) S. marginalis; 63) S. mesoamericanus; 64) S. mexicanus; 65) S. militaris; 66) S. molgorae; 67) S. monterrosoi; 68) S. nigricans; 69) S. oblongulus; 70) S. ovalis; 71) S. parallelicornis.

FIGURES 26 – 37. Habitus in dorsal view of Stenotarsus spp. Scale bar = 1 mm. 26 – 27) S. militaris; 28) S. molgorae; 29) S. monterrosoi; 30) S. nigricans; 31 – 32) S. oblongulus; 33) S. ovalis; 34) S. parallelicornis; 35) S. raramurii: 36) S. rubrocinctus; 37) S. rulfoi.

FIGURES 144 – 157. Structure of hind legs of Stenotarsus spp. 144 – 149 Hind leg. 150 – 153. Base of male metafemur. 154 – 157. Metatarsus. 144) S. exiguus; 145) S. globosus; 146) S. latipes; 147) S. nigricans; 148) S. spiropenis; 149) S. ovalis; 150) S. globosus; 151) S. raramuri; 152) S. rubrocinctus; 153) S. shockleyi; 154) S. globosus; 155) S. incisus; 156) S. spiropenis; 157) S. oblongulus.

FIGURES 158 – 173. Hind legs of male Stenotarsus spp. 158) S. cortesi; 159) S. exiguus; 160) S. globosus; 161) S. guatemalae; 162) S. incisus; 163) S. kafkai; 164) S. latipes; 165) S. lemniscatus; 166) S. marginalis; 167) S. mesoamericanus; 168) S. mexicanus; 169) S. militaris; 170) S. molgorae; 171) S. monterrosoi; 172) S. nigricans; 173) S. oblongulus.

FIGURES 174 – 185. 174 – 183. Hind legs of male Stenotarsus spp. 184 – 185. Hind legs of female Stenotarsus spp. 174) S. ovalis; 175) S. parallelicornis; 176) S. raramuri; 177) S. rubrocinctus; 178) S. rulfoi; 179) S. sallaei; 180) S. shockleyi; 181) S. smithi; 182) S. spiropenis; 183) S. thoracicus; 184) S. exiguus; 185) S. globosus.

FIGURES 186 – 195. Abdmonal structures of Stenotarsus spp. 186. Lateral view of abdomen of male S. sallaei. 187 – 191. Abdomen of female Stenotarsus spp. 192 – 195. Tergite VIII of female Stenotarsus spp. 187) S. globosus; 188) S. incisus; 189) S. militaris; 190) S. monterrosoi; 191) S. nigricans; 192) S. lemniscatus; 193) S. monterrosoi; 194) S. militaris; 195) S. nigricans.

FIGURES 72 – 78. Right antennae of Stenotarsus spp. 72) S. raramuri; 73) S. rulfoi; 74) S. sallaei; 75) S. shockleyi; 76) S. smithi; 77) S. spiropenis; 78) S. thoracicus.

FIGURES 38 – 42. Habitus in dorsal view of Stenotarsus spp. Scale bar = 1 mm .. 38) S. sallaei; 39) S. shockleyi; 40) S. smithi; 41) S. spiropenis: 42) S. thoracicus.