Stenotarsus oblongulus Gorham

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 : 33-35

Stenotarsus oblongulus Gorham

( Figs. 31–32 , 49 , 69 , 81 , 104 , 173 , 198 , 228 –229, 266 )

Stenotarsus oblongulus Gorham, 1890: 138 . Blackwelder 1945: 440, Strohecker 1953: 55; Shockley et al. 2009a: 84.

Diagnosis. This species is most similar to S. sallaei in the long oval body and pronotum with basal pores small and slightly elongate. Stenotarsus oblongulus can be separated from all other species in the region by the following combination of characters: body often contrastly colored, with pronotum and elytra red with large black markings ( Fig. 31 ); terminal antennomere with a small angle on margin ( Fig. 69 ); metatibia continuously widening apically, weakly curved ( Fig. 173 ); and by the abdominal ventrite I of males without protuberances.

Description of males. Body 4.7–5.0 mm long, long oval ( Figs. 31–32 ), weakly convex ( Fig. 49 ), 1.76–2.00X as long as wide, 2.95–3.20X as long as high. Uniformly reddish brown except antennomeres 7–11 black, 5–6 infuscated ( Fig. 32 ), or contrastly colored ( Fig. 31 ): head orange-red with mouthparts infuscate, antenna with antennomeres 3–7 gradually infuscate, segments 8–11 are black; pronotum with large semicircular or subquadrate black macula, hypomeron orange-red, pro and mesosternum weakly infuscate, scutellum orange-red to black, elytra red, each with large, oval, black macula, metasternum and metepisternum black, legs red or infuscate with trochanters, tibio-femoral joints and tarsi paler; abdomen orange-red with first ventrite mainly black. Densely covered with long, suberect, golden setae.

Head: Clypeus transverse, 2.2X wider than long. Terminal labial palpomere narrow, acuminate, narrowly truncate apically. Interocular distance 0.63X as wide as head. Antenna moderately long and slender ( Fig. 69 ), 0.44X as long as body; scape 0.2X as long as wide, 1.5X longer than pedicel; pedicel 1.3X longer than wide; third antennomere 1.7X as long as wide, 1.3X as long as pedicel; fourth and fifth subequal to third; sixth 1.6X as long as wide, 1.2X as long as pedicel; seventh 1.4X as long as wide, 1.3X as long as pedicel; eighth as long as wide, 1.1X longer than pedicel; antennal club 0.42X as long as total antennal length, with segments slightly asymmetrical; ninth antennomere weakly widened apically, 1.3X as long as wide, 2.2X as long as pedicel; tenth widened apically, as long as wide, 1.9X as long as pedicel; terminal antennomere slightly asymmetrical, almost continuously widened apically, with an angle on external margin near midlength, 2.3X as long as wide, 3.3X as long as pedicel. Prothorax: Pronotum widest at base, markedly transverse ( Figs. 81 , 104 ), 2.12–2.20X wider than long, 1.87–2.00X wider at base than at front angles, 2.11–2.25X wider than head. Sides convergent in basal half or 2/3, then slightly rounded to front angles. Front angles produced, right-angled. Hind angles briefly acute. Anterior margin narrow, not distinctly arcuate medially. Lateral margins weakly raised, comparatively narrow; width of margin at base less than 1/4 of the distance between basal pore and hind angle; area between marginal line and pronotal edge flat. Disc moderately convex, finely and closely punctate. Longitudinal sulci moderately deep and long, narrowing anteriorly, slightly convergent. Basal pores small, slightly elongate. Basal sulcus absent. Pronotal base lobed medially. Prosternal process wide at base, slightly widened posteriorly; as wide as longitudinal procoxal diameter apically.

Pterothorax: Scutellum triangular, moderately large, 1.76–1.85X wider than long, 0.16–0.19X as wide as pronotum. Elytra 3.15–3.45 mm long, 1.18X longer than wide, 3.7X longer and 1.44X wider than pronotum; long ovoid, widest at basal third, then roundly convergent to the rounded apex. Moderately densely punctate with foveolate punctures moderately large and deep, separated by 2.5–4.0 diameters, sparser and shallower apically and near scutellum. Humerus moderately prominent. Epipleuron moderately wide at base, 0.85X as wide as the intercoxal process of metaventrite. Mesoventrite deeply excavated in front, bearing small setose pores; mesoventral process slightly wider than longitudinal coxal diameter, without medial carinae. Metaventrite moderately convex, without modifications on anterior margin; with pair of small setose pores of approximately same diameter posterior to each mesocoxa. Metepisternum with small setose pore.

Legs: moderately long and slender ( Fig. 173 ). Trochanters simple. Meso- and metafemora moderately widened at midlength, unarmed; metafemur as long as mesofemur, bearing moderately long decumbent setae. Meso- and metatibiae moderately slender; metatibia as long as metafemur, 0.28–0.30X as long as elytra, widening apically, weakly curved, unarmed. Metatarsus 0.61–0.65X as long as metatibia; second tarsomere produced and lobed, 2.5X as wide apically as fourth tarsomere at midlength ( Fig. 198 ).

Abdomen: ventrite I slightly shorter than metaventrite and ventrites II–V combined, with moderately coarse foveolate punctation, without protuberances. Ventrite V slightly longer than IV, with apex truncate. Ventrite VI rounded apically. Tergite VIII truncate. Median lobe moderately long and narrow, narrowing in apical half with an apical crest, in ventral view ( Fig. 229 ); strongly widening in apical half, in lateral view ( Fig. 228 ). Tegmen with rather large submembranous tegminal plate ( Fig. 198 ).

Description of females. Body 4.80–5.05 mm long, 1.74–2.10X as long as wide, 3.0–3.2X as long as high. Antenna 0.42–0.43X as long as body. Pronotum 2.20–2.29X wider than long, 1.92–1.98X wider at base than at front angles, 2.15–2.28X wider than head. Elytra 3.25–3.56 mm long, 1.15–1.43X longer than wide, 3.60–4.00X longer and 1.26–1.41X wider than pronotum. Metatibia 0.28–0.32X longer than elytra. Metatarsus 0.49–0.54X as long as metatibia. Ovipositor with proctiger acuminate, coxites wide, without styli.

Sexual dimorphism. Females have slightly shorter antennae.

Variation. There are two basic color patterns in this species: a uniformly reddish brown form and a red colored form with large black maculae on elytra and pronotum. Some contrastly colored specimens have legs and antennae black, and pronotum almost completely black.

Material examined. Type. Holotype (female): Holotype [round, red bordered label] / type [round, orange bordered label] / Capetillo, Guatemala, G.C. Champion / Sp. figured / Sten. oblongulus Gorham [h] / B.C.A., Col., VII, Stenotarsus [p] oblongulus Gorh. [h] (NHM).

Other material. Trece Aguas, 7.4.0 6, Guate / Alta V. Paz, Guatemala / Barber & Scwarz Coll. / Stenotarsus distinguendus Arrow / Stenotarsus sallaei Gorh. ? / Stenotarsus distinguendus Arrow , dt. Stroh (1 male: NMNH); Mexico, Chiapas, Aguacatenan / P. Hubbell, VII.1975 (1 female: NMNH); Chiapas Mex, L. Hotzen ’19, Pacific Slope Cordilleras, 800–1000 (1 female: NMNH); México, Oaxaca, Candelaria, Loxicha, Finca La Media Luna, 26- VIII-2003, Alt. 550 m, Q. Santiago y L. Delgado / Stenotarsus sp. 14, E. Arriaga-Varela det. 2006 (3 males: IEXA); Juquila 15 / Mexico Coll. Flohr / augustulus Gerst. / not angustulus det. H.F. Strohecker (1 female: MNB); Cordoba, Mex / NLHKrauss, 1955 / Stenotarsus spp. (1 female: NMNH); [illegible] / Stenotarsus sp. prope . oblongulus Gorh. , det. H.F. Strohecker (1 male: MNB); S. Juan de la Punta 6 / claviger Gerst. (1 female: MNB). Distribution: GUATEMALA: Alta Verapaz, Quetzaltenango; MEXICO: Chiapas, Oaxaca, Veracruz ( Fig. 266 ).

Biological Notes. Altitudinal range: 550–1,000 m. Period of activity: July–August. Remarks. This is the first record of this species from México.

Figures

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 43 – 49. 43 – 47. Habitus in ventral view of Stenotarsus spp. 48 – 49 Habitus in lateral view of Stenotarsus spp. 43) S. guatemalae; 44) S. kafkai; 45) S. nigricans; 46) S. militaris; 47) S. thoracicus; 48) S. incisus; 49) S. oblongulus.

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 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 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 196 – 199. Aedeagus of Stenotarsus spp. 196) S. globosus, S. raramuri, S. rubrocinctus, S. shockleyi; 197) S. militaris; 198) S. oblongulus; 199) S. spiropenis.

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 266 – 267. Distributional maps of Stenotarsus spp. 266) S. oblongulus (C), S. spiropenis (S), S. rulfoi (T); 267) S. sallaei (C). Yellow circles (C), red squares (S), blue triangles (T)