Stenotarsus marginalis Arrow

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 : 24-25

Stenotarsus marginalis Arrow

(Figs. 23, 62, 79, 98, 141, 166, 216–217, 260)

Stenotarsus marginalis Arrow, 1920: 50 . Blackwelder 1945: 440; Strohecker 1953: 54; Shockley et al. 2009a: 83. Stenotarsus maculicollis Gorham, 1890: 141 (not Gerstaecker 1858: 333).

Diagnosis. This species is easily recognizable among all other species from the region by the markedly large, oblique basal pores on the pronotum ( Figs. 79 , 98 ), and the metaventrite with only one large setose pore posterior to each mesocoxa ( Fig. 141 ).

Description of males. Body 4.15 mm long, moderately long oval and convex ( Fig. 230 ), 1.9X as long as wide, 2.65X as long as high. Contrastly colored with antennae red with club black, head red, pronotum black, broadly margined laterally by red, elytra black, each margined by red stripe, venter red. Densely covered with comparatively long, suberect, coppery setae.

Head: Clypeus transverse, 2.0X wider than long. Terminal labial palpomere narrow, acuminate, narrowly truncate apically. Interocular distance 0.71X as wide as head. Antenna moderately long and rather stout ( Fig. 62 ), 0.41X as long as body; scape 1.2X as long as wide, 1.7X longer than pedicel; pedicel 0.8X longer than wide; third antennomere 0.9X as long as wide, 1X as long as pedicel; fourth to seventh subequal to third; eighth 0.8X as long as wide, 1.1X longer than pedicel; antennal club 0.48X as long as total antennal length, with segments almost symmetrical; ninth antennomere weakly widened apically, as long as wide, 1.9X as long as pedicel; tenth widened apically, 0.9X as long as wide, 2.1X as long as pedicel; terminal antennomere slightly asymmetrical, widest after midlength, 1.6X as long as wide, 4.2X as long as pedicel.

Prothorax: Pronotum ( Fig. 98 ) widest at base, markedly transverse, 2.35X wider than long, 1.9X wider at base than at front angles, 2.15X wider than head. Sides weakly convergent in basal half, then weakly rounded to front angles. Front angles produced, right-angled, weakly rounded at tip. Hind angles slightly acute. Anterior margin narrow, not arcuate medially. Lateral margins distinctly raised and wide, weakly narrowing near base; width of margin at base less than 1/2 of the distance between basal pore and hind angle; area between marginal line and pronotal edge flat to slightly concave. Disc moderately convex, finely and closely punctate. Longitudinal sulci very short and feeble. Basal pores remarkably large, elongate and oblique. Basal sulcus impressed, lacking at center. Pronotal base weakly lobed, nearly straight near scutellum. Prosternal process narrow at base, weakly widened posteriorly; as wide as 0.6X longitudinal procoxal diameter apically.

Pterothorax: Scutellum triangular, small, 1.3X wider than long, 0.14X as wide as pronotum. Elytra 2.63 mm long, 1.2X longer than wide, 3.35X longer and 1.18X wider than pronotum; ovoid, widest near basal third, then roundly converging to rounded apex; moderately densely punctate with foveolate punctures comparatively large and deep, separated by 1.5–3.5 diameters, sparser and shallower apically. Humerus weakly prominent. Epipleuron at base 0.8X as wide as intercoxal process of metaventrite. Mesoventrite deeply excavated in front; bearing small setose pores laterally; mesoventral process as wide as longitudinal coxal diameter, without medial carinae. Metaventrite markedly convex, without modifications near the anterior margin; with distinctly large setose pore posterior to each mesocoxa ( Fig. 141 ). Metepisternum with small setose pore.

Legs: moderately short and stout ( Fig. 166 ). Trochanters simple. Meso- and metafemora moderately stout, slightly widest at midlength, unarmed; metafemur slightly curved, as long as mesofemur, bearing moderately long decumbent setae. Meso- and metatibiae moderately stout; metatibia scarcely shorter than metafemur, 0.33X as long as elytra; weakly and gradually widened apically, linear, medial margin unarmed. Metatarsus 0.63X as long as metatibia; second tarsomere produced, as wide apically as fourth tarsomere at midlength.

Abdomen: ventrite I slightly shorter than metaventrite and as long as ventrites II–V combined, with sparse large foveolate punctation, without protuberances. Ventrite V markedly longer than IV, with apex briefly truncate. Ventrite VI rounded apically. Tergite VIII truncate. Median lobe narrow, curved, very weakly widened apically, in ventral ( Fig. 217 ) and lateral views ( Fig. 216 ). Tegmen with moderately large submembranous tegminal plate.

Description of female. Female unknown.

Sexual dimorphism. Unknown.

Material examined. Type. Holotype (male): Holotype [round, red bordered label] / Type H. T. [round, red bordered label] / Zapote, Guatemala, G.C. Champion / Stenotarsus maculicollis Gerstaecker [h] / B.C.A., VII, Stenotarsus [p] maculicollis Gerst. [h] / Sp. figured / Stenotarsus marginalis Arrow [h] (NHM).

Distribution. GUATEMALA: Quetzaltenango ( Fig. 260 ).

Remarks. This species was reported by Arriaga-Varela et al. (2007) from México. However, this record was based on a misidentification of specimens described here as Stenotarsus incisus sp. nov.

Figures

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 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 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 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 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 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 260 – 262. Distributional maps of Stenotarsus spp. 260) S. guatemalae (C), S. marginalis (S); 261) S. kafkai (C), S. mexicanus (S), S. nigricans (T); 262) S. latipes (C), S. shockleyi (S). Yellow circles (C), red squares (S), blue triangles (T).